[binutils-gdb.git] / gdb / remote.c

/* Remote target communications for serial-line targets in custom GDB protocol

   Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997,
   1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
   Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

/* See the GDB User Guide for details of the GDB remote protocol.  */

#include "defs.h"
#include "gdb_string.h"
#include <ctype.h>
#include <fcntl.h>
#include "inferior.h"
#include "bfd.h"
#include "symfile.h"
#include "exceptions.h"
#include "target.h"
/*#include "terminal.h" */
#include "gdbcmd.h"
#include "objfiles.h"
#include "gdb-stabs.h"
#include "gdbthread.h"
#include "remote.h"
#include "regcache.h"
#include "value.h"
#include "gdb_assert.h"
#include "observer.h"
#include "solib.h"
#include "cli/cli-decode.h"
#include "cli/cli-setshow.h"
#include "target-descriptions.h"

#include <ctype.h>
#include <sys/time.h>

#include "event-loop.h"
#include "event-top.h"
#include "inf-loop.h"

#include <signal.h>
#include "serial.h"

#include "gdbcore.h" /* for exec_bfd */

#include "remote-fileio.h"
#include "gdb/fileio.h"
#include "gdb_stat.h"

#include "memory-map.h"

/* The size to align memory write packets, when practical.  The protocol
   does not guarantee any alignment, and gdb will generate short
   writes and unaligned writes, but even as a best-effort attempt this
   can improve bulk transfers.  For instance, if a write is misaligned
   relative to the target's data bus, the stub may need to make an extra
   round trip fetching data from the target.  This doesn't make a
   huge difference, but it's easy to do, so we try to be helpful.

   The alignment chosen is arbitrary; usually data bus width is
   important here, not the possibly larger cache line size.  */
enum { REMOTE_ALIGN_WRITES = 16 };

/* Prototypes for local functions.  */
static void cleanup_sigint_signal_handler (void *dummy);
static void initialize_sigint_signal_handler (void);
static int getpkt_sane (char **buf, long *sizeof_buf, int forever);
static int getpkt_or_notif_sane (char **buf, long *sizeof_buf,
                                 int forever);

static void handle_remote_sigint (int);
static void handle_remote_sigint_twice (int);
static void async_remote_interrupt (gdb_client_data);
void async_remote_interrupt_twice (gdb_client_data);

static void remote_files_info (struct target_ops *ignore);

static void remote_prepare_to_store (struct regcache *regcache);

static void remote_fetch_registers (struct regcache *regcache, int regno);

static void remote_resume (ptid_t ptid, int step,
                           enum target_signal siggnal);
static void remote_open (char *name, int from_tty);

static void extended_remote_open (char *name, int from_tty);

static void remote_open_1 (char *, int, struct target_ops *, int extended_p);

static void remote_close (int quitting);

static void remote_store_registers (struct regcache *regcache, int regno);

static void remote_mourn (struct target_ops *ops);

static void extended_remote_restart (void);

static void extended_remote_mourn (struct target_ops *);

static void remote_mourn_1 (struct target_ops *);

static void remote_send (char **buf, long *sizeof_buf_p);

static int readchar (int timeout);

static ptid_t remote_wait (ptid_t ptid,
                           struct target_waitstatus *status);

static void remote_kill (void);

static int tohex (int nib);

static int remote_can_async_p (void);

static int remote_is_async_p (void);

static void remote_async (void (*callback) (enum inferior_event_type event_type,
                                            void *context), void *context);

static int remote_async_mask (int new_mask);

static void remote_detach (struct target_ops *ops, char *args, int from_tty);

static void remote_interrupt (int signo);

static void remote_interrupt_twice (int signo);

static void interrupt_query (void);

static void set_general_thread (struct ptid ptid);
static void set_continue_thread (struct ptid ptid);

static int remote_thread_alive (ptid_t);

static void get_offsets (void);

static void skip_frame (void);

static long read_frame (char **buf_p, long *sizeof_buf);

static int hexnumlen (ULONGEST num);

static void init_remote_ops (void);

static void init_extended_remote_ops (void);

static void remote_stop (ptid_t);

static int ishex (int ch, int *val);

static int stubhex (int ch);

static int hexnumstr (char *, ULONGEST);

static int hexnumnstr (char *, ULONGEST, int);

static CORE_ADDR remote_address_masked (CORE_ADDR);

static void print_packet (char *);

static unsigned long crc32 (unsigned char *, int, unsigned int);

static void compare_sections_command (char *, int);

static void packet_command (char *, int);

static int stub_unpack_int (char *buff, int fieldlength);

static ptid_t remote_current_thread (ptid_t oldptid);

static void remote_find_new_threads (void);

static void record_currthread (ptid_t currthread);

static int fromhex (int a);

static int hex2bin (const char *hex, gdb_byte *bin, int count);

static int bin2hex (const gdb_byte *bin, char *hex, int count);

static int putpkt_binary (char *buf, int cnt);

static void check_binary_download (CORE_ADDR addr);

struct packet_config;

static void show_packet_config_cmd (struct packet_config *config);

static void update_packet_config (struct packet_config *config);

static void set_remote_protocol_packet_cmd (char *args, int from_tty,
                                            struct cmd_list_element *c);

static void show_remote_protocol_packet_cmd (struct ui_file *file,
                                             int from_tty,
                                             struct cmd_list_element *c,
                                             const char *value);

static char *write_ptid (char *buf, const char *endbuf, ptid_t ptid);
static ptid_t read_ptid (char *buf, char **obuf);

static void remote_query_supported (void);

static void remote_check_symbols (struct objfile *objfile);

void _initialize_remote (void);

struct stop_reply;
static struct stop_reply *stop_reply_xmalloc (void);
static void stop_reply_xfree (struct stop_reply *);
static void do_stop_reply_xfree (void *arg);
static void remote_parse_stop_reply (char *buf, struct stop_reply *);
static void push_stop_reply (struct stop_reply *);
static void remote_get_pending_stop_replies (void);
static void discard_pending_stop_replies (int pid);
static int peek_stop_reply (ptid_t ptid);

static void remote_async_inferior_event_handler (gdb_client_data);
static void remote_async_get_pending_events_handler (gdb_client_data);

static void remote_terminal_ours (void);

/* The non-stop remote protocol provisions for one pending stop reply.
   This is where we keep it until it is acknowledged.  */

static struct stop_reply *pending_stop_reply = NULL;

/* For "remote".  */

static struct cmd_list_element *remote_cmdlist;

/* For "set remote" and "show remote".  */

static struct cmd_list_element *remote_set_cmdlist;
static struct cmd_list_element *remote_show_cmdlist;

/* Description of the remote protocol state for the currently
   connected target.  This is per-target state, and independent of the
   selected architecture.  */

struct remote_state
{
  /* A buffer to use for incoming packets, and its current size.  The
     buffer is grown dynamically for larger incoming packets.
     Outgoing packets may also be constructed in this buffer.
     BUF_SIZE is always at least REMOTE_PACKET_SIZE;
     REMOTE_PACKET_SIZE should be used to limit the length of outgoing
     packets.  */
  char *buf;
  long buf_size;

  /* If we negotiated packet size explicitly (and thus can bypass
     heuristics for the largest packet size that will not overflow
     a buffer in the stub), this will be set to that packet size.
     Otherwise zero, meaning to use the guessed size.  */
  long explicit_packet_size;

  /* remote_wait is normally called when the target is running and
     waits for a stop reply packet.  But sometimes we need to call it
     when the target is already stopped.  We can send a "?" packet
     and have remote_wait read the response.  Or, if we already have
     the response, we can stash it in BUF and tell remote_wait to
     skip calling getpkt.  This flag is set when BUF contains a
     stop reply packet and the target is not waiting.  */
  int cached_wait_status;

  /* True, if in no ack mode.  That is, neither GDB nor the stub will
     expect acks from each other.  The connection is assumed to be
     reliable.  */
  int noack_mode;

  /* True if we're connected in extended remote mode.  */
  int extended;

  /* True if the stub reported support for multi-process
     extensions.  */
  int multi_process_aware;

  /* True if we resumed the target and we're waiting for the target to
     stop.  In the mean time, we can't start another command/query.
     The remote server wouldn't be ready to process it, so we'd
     timeout waiting for a reply that would never come and eventually
     we'd close the connection.  This can happen in asynchronous mode
     because we allow GDB commands while the target is running.  */
  int waiting_for_stop_reply;

  /* True if the stub reports support for non-stop mode.  */
  int non_stop_aware;

  /* True if the stub reports support for vCont;t.  */
  int support_vCont_t;
};

/* Returns true if the multi-process extensions are in effect.  */
static int
remote_multi_process_p (struct remote_state *rs)
{
  return rs->extended && rs->multi_process_aware;
}

/* This data could be associated with a target, but we do not always
   have access to the current target when we need it, so for now it is
   static.  This will be fine for as long as only one target is in use
   at a time.  */
static struct remote_state remote_state;

static struct remote_state *
get_remote_state_raw (void)
{
  return &remote_state;
}

/* Description of the remote protocol for a given architecture.  */

struct packet_reg
{
  long offset; /* Offset into G packet.  */
  long regnum; /* GDB's internal register number.  */
  LONGEST pnum; /* Remote protocol register number.  */
  int in_g_packet; /* Always part of G packet.  */
  /* long size in bytes;  == register_size (target_gdbarch, regnum);
     at present.  */
  /* char *name; == gdbarch_register_name (target_gdbarch, regnum);
     at present.  */
};

struct remote_arch_state
{
  /* Description of the remote protocol registers.  */
  long sizeof_g_packet;

  /* Description of the remote protocol registers indexed by REGNUM
     (making an array gdbarch_num_regs in size).  */
  struct packet_reg *regs;

  /* This is the size (in chars) of the first response to the ``g''
     packet.  It is used as a heuristic when determining the maximum
     size of memory-read and memory-write packets.  A target will
     typically only reserve a buffer large enough to hold the ``g''
     packet.  The size does not include packet overhead (headers and
     trailers).  */
  long actual_register_packet_size;

  /* This is the maximum size (in chars) of a non read/write packet.
     It is also used as a cap on the size of read/write packets.  */
  long remote_packet_size;
};


/* Handle for retreving the remote protocol data from gdbarch.  */
static struct gdbarch_data *remote_gdbarch_data_handle;

static struct remote_arch_state *
get_remote_arch_state (void)
{
  return gdbarch_data (target_gdbarch, remote_gdbarch_data_handle);
}

/* Fetch the global remote target state.  */

static struct remote_state *
get_remote_state (void)
{
  /* Make sure that the remote architecture state has been
     initialized, because doing so might reallocate rs->buf.  Any
     function which calls getpkt also needs to be mindful of changes
     to rs->buf, but this call limits the number of places which run
     into trouble.  */
  get_remote_arch_state ();

  return get_remote_state_raw ();
}

static int
compare_pnums (const void *lhs_, const void *rhs_)
{
  const struct packet_reg * const *lhs = lhs_;
  const struct packet_reg * const *rhs = rhs_;

  if ((*lhs)->pnum < (*rhs)->pnum)
    return -1;
  else if ((*lhs)->pnum == (*rhs)->pnum)
    return 0;
  else
    return 1;
}

static void *
init_remote_state (struct gdbarch *gdbarch)
{
  int regnum, num_remote_regs, offset;
  struct remote_state *rs = get_remote_state_raw ();
  struct remote_arch_state *rsa;
  struct packet_reg **remote_regs;

  rsa = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct remote_arch_state);

  /* Use the architecture to build a regnum<->pnum table, which will be
     1:1 unless a feature set specifies otherwise.  */
  rsa->regs = GDBARCH_OBSTACK_CALLOC (gdbarch,
                                      gdbarch_num_regs (gdbarch),
                                      struct packet_reg);
  for (regnum = 0; regnum < gdbarch_num_regs (gdbarch); regnum++)
    {
      struct packet_reg *r = &rsa->regs[regnum];

      if (register_size (gdbarch, regnum) == 0)
        /* Do not try to fetch zero-sized (placeholder) registers.  */
        r->pnum = -1;
      else
        r->pnum = gdbarch_remote_register_number (gdbarch, regnum);

      r->regnum = regnum;
    }

  /* Define the g/G packet format as the contents of each register
     with a remote protocol number, in order of ascending protocol
     number.  */

  remote_regs = alloca (gdbarch_num_regs (gdbarch)
                          * sizeof (struct packet_reg *));
  for (num_remote_regs = 0, regnum = 0;
       regnum < gdbarch_num_regs (gdbarch);
       regnum++)
    if (rsa->regs[regnum].pnum != -1)
      remote_regs[num_remote_regs++] = &rsa->regs[regnum];

  qsort (remote_regs, num_remote_regs, sizeof (struct packet_reg *),
         compare_pnums);

  for (regnum = 0, offset = 0; regnum < num_remote_regs; regnum++)
    {
      remote_regs[regnum]->in_g_packet = 1;
      remote_regs[regnum]->offset = offset;
      offset += register_size (gdbarch, remote_regs[regnum]->regnum);
    }

  /* Record the maximum possible size of the g packet - it may turn out
     to be smaller.  */
  rsa->sizeof_g_packet = offset;

  /* Default maximum number of characters in a packet body. Many
     remote stubs have a hardwired buffer size of 400 bytes
     (c.f. BUFMAX in m68k-stub.c and i386-stub.c).  BUFMAX-1 is used
     as the maximum packet-size to ensure that the packet and an extra
     NUL character can always fit in the buffer.  This stops GDB
     trashing stubs that try to squeeze an extra NUL into what is
     already a full buffer (As of 1999-12-04 that was most stubs).  */
  rsa->remote_packet_size = 400 - 1;

  /* This one is filled in when a ``g'' packet is received.  */
  rsa->actual_register_packet_size = 0;

  /* Should rsa->sizeof_g_packet needs more space than the
     default, adjust the size accordingly. Remember that each byte is
     encoded as two characters. 32 is the overhead for the packet
     header / footer. NOTE: cagney/1999-10-26: I suspect that 8
     (``$NN:G...#NN'') is a better guess, the below has been padded a
     little.  */
  if (rsa->sizeof_g_packet > ((rsa->remote_packet_size - 32) / 2))
    rsa->remote_packet_size = (rsa->sizeof_g_packet * 2 + 32);

  /* Make sure that the packet buffer is plenty big enough for
     this architecture.  */
  if (rs->buf_size < rsa->remote_packet_size)
    {
      rs->buf_size = 2 * rsa->remote_packet_size;
      rs->buf = xrealloc (rs->buf, rs->buf_size);
    }

  return rsa;
}

/* Return the current allowed size of a remote packet.  This is
   inferred from the current architecture, and should be used to
   limit the length of outgoing packets.  */
static long
get_remote_packet_size (void)
{
  struct remote_state *rs = get_remote_state ();
  struct remote_arch_state *rsa = get_remote_arch_state ();

  if (rs->explicit_packet_size)
    return rs->explicit_packet_size;

  return rsa->remote_packet_size;
}

static struct packet_reg *
packet_reg_from_regnum (struct remote_arch_state *rsa, long regnum)
{
  if (regnum < 0 && regnum >= gdbarch_num_regs (target_gdbarch))
    return NULL;
  else
    {
      struct packet_reg *r = &rsa->regs[regnum];
      gdb_assert (r->regnum == regnum);
      return r;
    }
}

static struct packet_reg *
packet_reg_from_pnum (struct remote_arch_state *rsa, LONGEST pnum)
{
  int i;
  for (i = 0; i < gdbarch_num_regs (target_gdbarch); i++)
    {
      struct packet_reg *r = &rsa->regs[i];
      if (r->pnum == pnum)
        return r;
    }
  return NULL;
}

/* FIXME: graces/2002-08-08: These variables should eventually be
   bound to an instance of the target object (as in gdbarch-tdep()),
   when such a thing exists.  */

/* This is set to the data address of the access causing the target
   to stop for a watchpoint.  */
static CORE_ADDR remote_watch_data_address;

/* This is non-zero if target stopped for a watchpoint.  */
static int remote_stopped_by_watchpoint_p;

static struct target_ops remote_ops;

static struct target_ops extended_remote_ops;

static int remote_async_mask_value = 1;

/* FIXME: cagney/1999-09-23: Even though getpkt was called with
   ``forever'' still use the normal timeout mechanism.  This is
   currently used by the ASYNC code to guarentee that target reads
   during the initial connect always time-out.  Once getpkt has been
   modified to return a timeout indication and, in turn
   remote_wait()/wait_for_inferior() have gained a timeout parameter
   this can go away.  */
static int wait_forever_enabled_p = 1;


/* This variable chooses whether to send a ^C or a break when the user
   requests program interruption.  Although ^C is usually what remote
   systems expect, and that is the default here, sometimes a break is
   preferable instead.  */

static int remote_break;

/* Descriptor for I/O to remote machine.  Initialize it to NULL so that
   remote_open knows that we don't have a file open when the program
   starts.  */
static struct serial *remote_desc = NULL;

/* This variable sets the number of bits in an address that are to be
   sent in a memory ("M" or "m") packet.  Normally, after stripping
   leading zeros, the entire address would be sent. This variable
   restricts the address to REMOTE_ADDRESS_SIZE bits.  HISTORY: The
   initial implementation of remote.c restricted the address sent in
   memory packets to ``host::sizeof long'' bytes - (typically 32
   bits).  Consequently, for 64 bit targets, the upper 32 bits of an
   address was never sent.  Since fixing this bug may cause a break in
   some remote targets this variable is principly provided to
   facilitate backward compatibility.  */

static int remote_address_size;

/* Temporary to track who currently owns the terminal.  See
   remote_terminal_* for more details.  */

static int remote_async_terminal_ours_p;

/* The executable file to use for "run" on the remote side.  */

static char *remote_exec_file = "";

\f
/* User configurable variables for the number of characters in a
   memory read/write packet.  MIN (rsa->remote_packet_size,
   rsa->sizeof_g_packet) is the default.  Some targets need smaller
   values (fifo overruns, et.al.) and some users need larger values
   (speed up transfers).  The variables ``preferred_*'' (the user
   request), ``current_*'' (what was actually set) and ``forced_*''
   (Positive - a soft limit, negative - a hard limit).  */

struct memory_packet_config
{
  char *name;
  long size;
  int fixed_p;
};

/* Compute the current size of a read/write packet.  Since this makes
   use of ``actual_register_packet_size'' the computation is dynamic.  */

static long
get_memory_packet_size (struct memory_packet_config *config)
{
  struct remote_state *rs = get_remote_state ();
  struct remote_arch_state *rsa = get_remote_arch_state ();

  /* NOTE: The somewhat arbitrary 16k comes from the knowledge (folk
     law?) that some hosts don't cope very well with large alloca()
     calls.  Eventually the alloca() code will be replaced by calls to
     xmalloc() and make_cleanups() allowing this restriction to either
     be lifted or removed.  */
#ifndef MAX_REMOTE_PACKET_SIZE
#define MAX_REMOTE_PACKET_SIZE 16384
#endif
  /* NOTE: 20 ensures we can write at least one byte.  */
#ifndef MIN_REMOTE_PACKET_SIZE
#define MIN_REMOTE_PACKET_SIZE 20
#endif
  long what_they_get;
  if (config->fixed_p)
    {
      if (config->size <= 0)
        what_they_get = MAX_REMOTE_PACKET_SIZE;
      else
        what_they_get = config->size;
    }
  else
    {
      what_they_get = get_remote_packet_size ();
      /* Limit the packet to the size specified by the user.  */
      if (config->size > 0
          && what_they_get > config->size)
        what_they_get = config->size;

      /* Limit it to the size of the targets ``g'' response unless we have
         permission from the stub to use a larger packet size.  */
      if (rs->explicit_packet_size == 0
          && rsa->actual_register_packet_size > 0
          && what_they_get > rsa->actual_register_packet_size)
        what_they_get = rsa->actual_register_packet_size;
    }
  if (what_they_get > MAX_REMOTE_PACKET_SIZE)
    what_they_get = MAX_REMOTE_PACKET_SIZE;
  if (what_they_get < MIN_REMOTE_PACKET_SIZE)
    what_they_get = MIN_REMOTE_PACKET_SIZE;

  /* Make sure there is room in the global buffer for this packet
     (including its trailing NUL byte).  */
  if (rs->buf_size < what_they_get + 1)
    {
      rs->buf_size = 2 * what_they_get;
      rs->buf = xrealloc (rs->buf, 2 * what_they_get);
    }

  return what_they_get;
}

/* Update the size of a read/write packet. If they user wants
   something really big then do a sanity check.  */

static void
set_memory_packet_size (char *args, struct memory_packet_config *config)
{
  int fixed_p = config->fixed_p;
  long size = config->size;
  if (args == NULL)
    error (_("Argument required (integer, `fixed' or `limited')."));
  else if (strcmp (args, "hard") == 0
      || strcmp (args, "fixed") == 0)
    fixed_p = 1;
  else if (strcmp (args, "soft") == 0
           || strcmp (args, "limit") == 0)
    fixed_p = 0;
  else
    {
      char *end;
      size = strtoul (args, &end, 0);
      if (args == end)
        error (_("Invalid %s (bad syntax)."), config->name);
#if 0
      /* Instead of explicitly capping the size of a packet to
         MAX_REMOTE_PACKET_SIZE or dissallowing it, the user is
         instead allowed to set the size to something arbitrarily
         large.  */
      if (size > MAX_REMOTE_PACKET_SIZE)
        error (_("Invalid %s (too large)."), config->name);
#endif
    }
  /* Extra checks?  */
  if (fixed_p && !config->fixed_p)
    {
      if (! query (_("The target may not be able to correctly handle a %s\n"
                   "of %ld bytes. Change the packet size? "),
                   config->name, size))
        error (_("Packet size not changed."));
    }
  /* Update the config.  */
  config->fixed_p = fixed_p;
  config->size = size;
}

static void
show_memory_packet_size (struct memory_packet_config *config)
{
  printf_filtered (_("The %s is %ld. "), config->name, config->size);
  if (config->fixed_p)
    printf_filtered (_("Packets are fixed at %ld bytes.\n"),
                     get_memory_packet_size (config));
  else
    printf_filtered (_("Packets are limited to %ld bytes.\n"),
                     get_memory_packet_size (config));
}

static struct memory_packet_config memory_write_packet_config =
{
  "memory-write-packet-size",
};

static void
set_memory_write_packet_size (char *args, int from_tty)
{
  set_memory_packet_size (args, &memory_write_packet_config);
}

static void
show_memory_write_packet_size (char *args, int from_tty)
{
  show_memory_packet_size (&memory_write_packet_config);
}

static long
get_memory_write_packet_size (void)
{
  return get_memory_packet_size (&memory_write_packet_config);
}

static struct memory_packet_config memory_read_packet_config =
{
  "memory-read-packet-size",
};

static void
set_memory_read_packet_size (char *args, int from_tty)
{
  set_memory_packet_size (args, &memory_read_packet_config);
}

static void
show_memory_read_packet_size (char *args, int from_tty)
{
  show_memory_packet_size (&memory_read_packet_config);
}

static long
get_memory_read_packet_size (void)
{
  long size = get_memory_packet_size (&memory_read_packet_config);
  /* FIXME: cagney/1999-11-07: Functions like getpkt() need to get an
     extra buffer size argument before the memory read size can be
     increased beyond this.  */
  if (size > get_remote_packet_size ())
    size = get_remote_packet_size ();
  return size;
}

\f
/* Generic configuration support for packets the stub optionally
   supports. Allows the user to specify the use of the packet as well
   as allowing GDB to auto-detect support in the remote stub.  */

enum packet_support
  {
    PACKET_SUPPORT_UNKNOWN = 0,
    PACKET_ENABLE,
    PACKET_DISABLE
  };

struct packet_config
  {
    const char *name;
    const char *title;
    enum auto_boolean detect;
    enum packet_support support;
  };

/* Analyze a packet's return value and update the packet config
   accordingly.  */

enum packet_result
{
  PACKET_ERROR,
  PACKET_OK,
  PACKET_UNKNOWN
};

static void
update_packet_config (struct packet_config *config)
{
  switch (config->detect)
    {
    case AUTO_BOOLEAN_TRUE:
      config->support = PACKET_ENABLE;
      break;
    case AUTO_BOOLEAN_FALSE:
      config->support = PACKET_DISABLE;
      break;
    case AUTO_BOOLEAN_AUTO:
      config->support = PACKET_SUPPORT_UNKNOWN;
      break;
    }
}

static void
show_packet_config_cmd (struct packet_config *config)
{
  char *support = "internal-error";
  switch (config->support)
    {
    case PACKET_ENABLE:
      support = "enabled";
      break;
    case PACKET_DISABLE:
      support = "disabled";
      break;
    case PACKET_SUPPORT_UNKNOWN:
      support = "unknown";
      break;
    }
  switch (config->detect)
    {
    case AUTO_BOOLEAN_AUTO:
      printf_filtered (_("Support for the `%s' packet is auto-detected, currently %s.\n"),
                       config->name, support);
      break;
    case AUTO_BOOLEAN_TRUE:
    case AUTO_BOOLEAN_FALSE:
      printf_filtered (_("Support for the `%s' packet is currently %s.\n"),
                       config->name, support);
      break;
    }
}

static void
add_packet_config_cmd (struct packet_config *config, const char *name,
                       const char *title, int legacy)
{
  char *set_doc;
  char *show_doc;
  char *cmd_name;

  config->name = name;
  config->title = title;
  config->detect = AUTO_BOOLEAN_AUTO;
  config->support = PACKET_SUPPORT_UNKNOWN;
  set_doc = xstrprintf ("Set use of remote protocol `%s' (%s) packet",
                        name, title);
  show_doc = xstrprintf ("Show current use of remote protocol `%s' (%s) packet",
                         name, title);
  /* set/show TITLE-packet {auto,on,off} */
  cmd_name = xstrprintf ("%s-packet", title);
  add_setshow_auto_boolean_cmd (cmd_name, class_obscure,
                                &config->detect, set_doc, show_doc, NULL, /* help_doc */
                                set_remote_protocol_packet_cmd,
                                show_remote_protocol_packet_cmd,
                                &remote_set_cmdlist, &remote_show_cmdlist);
  /* set/show remote NAME-packet {auto,on,off} -- legacy.  */
  if (legacy)
    {
      char *legacy_name;
      legacy_name = xstrprintf ("%s-packet", name);
      add_alias_cmd (legacy_name, cmd_name, class_obscure, 0,
                     &remote_set_cmdlist);
      add_alias_cmd (legacy_name, cmd_name, class_obscure, 0,
                     &remote_show_cmdlist);
    }
}

static enum packet_result
packet_check_result (const char *buf)
{
  if (buf[0] != '\0')
    {
      /* The stub recognized the packet request.  Check that the
         operation succeeded.  */
      if (buf[0] == 'E'
          && isxdigit (buf[1]) && isxdigit (buf[2])
          && buf[3] == '\0')
        /* "Enn"  - definitly an error.  */
        return PACKET_ERROR;

      /* Always treat "E." as an error.  This will be used for
         more verbose error messages, such as E.memtypes.  */
      if (buf[0] == 'E' && buf[1] == '.')
        return PACKET_ERROR;

      /* The packet may or may not be OK.  Just assume it is.  */
      return PACKET_OK;
    }
  else
    /* The stub does not support the packet.  */
    return PACKET_UNKNOWN;
}

static enum packet_result
packet_ok (const char *buf, struct packet_config *config)
{
  enum packet_result result;

  result = packet_check_result (buf);
  switch (result)
    {
    case PACKET_OK:
    case PACKET_ERROR:
      /* The stub recognized the packet request.  */
      switch (config->support)
        {
        case PACKET_SUPPORT_UNKNOWN:
          if (remote_debug)
            fprintf_unfiltered (gdb_stdlog,
                                    "Packet %s (%s) is supported\n",
                                    config->name, config->title);
          config->support = PACKET_ENABLE;
          break;
        case PACKET_DISABLE:
          internal_error (__FILE__, __LINE__,
                          _("packet_ok: attempt to use a disabled packet"));
          break;
        case PACKET_ENABLE:
          break;
        }
      break;
    case PACKET_UNKNOWN:
      /* The stub does not support the packet.  */
      switch (config->support)
        {
        case PACKET_ENABLE:
          if (config->detect == AUTO_BOOLEAN_AUTO)
            /* If the stub previously indicated that the packet was
               supported then there is a protocol error..  */
            error (_("Protocol error: %s (%s) conflicting enabled responses."),
                   config->name, config->title);
          else
            /* The user set it wrong.  */
            error (_("Enabled packet %s (%s) not recognized by stub"),
                   config->name, config->title);
          break;
        case PACKET_SUPPORT_UNKNOWN:
          if (remote_debug)
            fprintf_unfiltered (gdb_stdlog,
                                "Packet %s (%s) is NOT supported\n",
                                config->name, config->title);
          config->support = PACKET_DISABLE;
          break;
        case PACKET_DISABLE:
          break;
        }
      break;
    }

  return result;
}

enum {
  PACKET_vCont = 0,
  PACKET_X,
  PACKET_qSymbol,
  PACKET_P,
  PACKET_p,
  PACKET_Z0,
  PACKET_Z1,
  PACKET_Z2,
  PACKET_Z3,
  PACKET_Z4,
  PACKET_vFile_open,
  PACKET_vFile_pread,
  PACKET_vFile_pwrite,
  PACKET_vFile_close,
  PACKET_vFile_unlink,
  PACKET_qXfer_auxv,
  PACKET_qXfer_features,
  PACKET_qXfer_libraries,
  PACKET_qXfer_memory_map,
  PACKET_qXfer_spu_read,
  PACKET_qXfer_spu_write,
  PACKET_qGetTLSAddr,
  PACKET_qSupported,
  PACKET_QPassSignals,
  PACKET_qSearch_memory,
  PACKET_vAttach,
  PACKET_vRun,
  PACKET_QStartNoAckMode,
  PACKET_vKill,
  PACKET_MAX
};

static struct packet_config remote_protocol_packets[PACKET_MAX];

static void
set_remote_protocol_packet_cmd (char *args, int from_tty,
                                struct cmd_list_element *c)
{
  struct packet_config *packet;

  for (packet = remote_protocol_packets;
       packet < &remote_protocol_packets[PACKET_MAX];
       packet++)
    {
      if (&packet->detect == c->var)
        {
          update_packet_config (packet);
          return;
        }
    }
  internal_error (__FILE__, __LINE__, "Could not find config for %s",
                  c->name);
}

static void
show_remote_protocol_packet_cmd (struct ui_file *file, int from_tty,
                                 struct cmd_list_element *c,
                                 const char *value)
{
  struct packet_config *packet;

  for (packet = remote_protocol_packets;
       packet < &remote_protocol_packets[PACKET_MAX];
       packet++)
    {
      if (&packet->detect == c->var)
        {
          show_packet_config_cmd (packet);
          return;
        }
    }
  internal_error (__FILE__, __LINE__, "Could not find config for %s",
                  c->name);
}

/* Should we try one of the 'Z' requests?  */

enum Z_packet_type
{
  Z_PACKET_SOFTWARE_BP,
  Z_PACKET_HARDWARE_BP,
  Z_PACKET_WRITE_WP,
  Z_PACKET_READ_WP,
  Z_PACKET_ACCESS_WP,
  NR_Z_PACKET_TYPES
};

/* For compatibility with older distributions.  Provide a ``set remote
   Z-packet ...'' command that updates all the Z packet types.  */

static enum auto_boolean remote_Z_packet_detect;

static void
set_remote_protocol_Z_packet_cmd (char *args, int from_tty,
                                  struct cmd_list_element *c)
{
  int i;
  for (i = 0; i < NR_Z_PACKET_TYPES; i++)
    {
      remote_protocol_packets[PACKET_Z0 + i].detect = remote_Z_packet_detect;
      update_packet_config (&remote_protocol_packets[PACKET_Z0 + i]);
    }
}

static void
show_remote_protocol_Z_packet_cmd (struct ui_file *file, int from_tty,
                                   struct cmd_list_element *c,
                                   const char *value)
{
  int i;
  for (i = 0; i < NR_Z_PACKET_TYPES; i++)
    {
      show_packet_config_cmd (&remote_protocol_packets[PACKET_Z0 + i]);
    }
}

/* Should we try the 'ThreadInfo' query packet?

   This variable (NOT available to the user: auto-detect only!)
   determines whether GDB will use the new, simpler "ThreadInfo"
   query or the older, more complex syntax for thread queries.
   This is an auto-detect variable (set to true at each connect,
   and set to false when the target fails to recognize it).  */

static int use_threadinfo_query;
static int use_threadextra_query;

/* Tokens for use by the asynchronous signal handlers for SIGINT.  */
static struct async_signal_handler *sigint_remote_twice_token;
static struct async_signal_handler *sigint_remote_token;

\f
/* Asynchronous signal handle registered as event loop source for
   when we have pending events ready to be passed to the core.  */

static struct async_event_handler *remote_async_inferior_event_token;

/* Asynchronous signal handle registered as event loop source for when
   the remote sent us a %Stop notification.  The registered callback
   will do a vStopped sequence to pull the rest of the events out of
   the remote side into our event queue.  */

static struct async_event_handler *remote_async_get_pending_events_token;
\f

static ptid_t magic_null_ptid;
static ptid_t not_sent_ptid;
static ptid_t any_thread_ptid;

/* These are the threads which we last sent to the remote system.  The
   TID member will be -1 for all or -2 for not sent yet.  */

static ptid_t general_thread;
static ptid_t continue_thread;

static void
notice_new_inferiors (ptid_t currthread)
{
  /* If this is a new thread, add it to GDB's thread list.
     If we leave it up to WFI to do this, bad things will happen.  */

  if (in_thread_list (currthread) && is_exited (currthread))
    {
      /* We're seeing an event on a thread id we knew had exited.
         This has to be a new thread reusing the old id.  Add it.  */
      add_thread (currthread);
      return;
    }

  if (!in_thread_list (currthread))
    {
      if (ptid_equal (pid_to_ptid (ptid_get_pid (currthread)), inferior_ptid))
        {
          /* inferior_ptid has no thread member yet.  This can happen
             with the vAttach -> remote_wait,"TAAthread:" path if the
             stub doesn't support qC.  This is the first stop reported
             after an attach, so this is the main thread.  Update the
             ptid in the thread list.  */
          thread_change_ptid (inferior_ptid, currthread);
          return;
        }

      if (ptid_equal (magic_null_ptid, inferior_ptid))
        {
          /* inferior_ptid is not set yet.  This can happen with the
             vRun -> remote_wait,"TAAthread:" path if the stub
             doesn't support qC.  This is the first stop reported
             after an attach, so this is the main thread.  Update the
             ptid in the thread list.  */
          thread_change_ptid (inferior_ptid, currthread);
          return;
        }

      /* When connecting to a target remote, or to a target
         extended-remote which already was debugging an inferior, we
         may not know about it yet.  Add it before adding its child
         thread, so notifications are emitted in a sensible order.  */
      if (!in_inferior_list (ptid_get_pid (currthread)))
        add_inferior (ptid_get_pid (currthread));

      /* This is really a new thread.  Add it.  */
      add_thread (currthread);
    }
}

/* Call this function as a result of
   1) A halt indication (T packet) containing a thread id
   2) A direct query of currthread
   3) Successful execution of set thread
 */

static void
record_currthread (ptid_t currthread)
{
  general_thread = currthread;

  if (ptid_equal (currthread, minus_one_ptid))
    /* We're just invalidating the local thread mirror.  */
    return;

  notice_new_inferiors (currthread);
}

static char *last_pass_packet;

/* If 'QPassSignals' is supported, tell the remote stub what signals
   it can simply pass through to the inferior without reporting.  */

static void
remote_pass_signals (void)
{
  if (remote_protocol_packets[PACKET_QPassSignals].support != PACKET_DISABLE)
    {
      char *pass_packet, *p;
      int numsigs = (int) TARGET_SIGNAL_LAST;
      int count = 0, i;

      gdb_assert (numsigs < 256);
      for (i = 0; i < numsigs; i++)
        {
          if (signal_stop_state (i) == 0
              && signal_print_state (i) == 0
              && signal_pass_state (i) == 1)
            count++;
        }
      pass_packet = xmalloc (count * 3 + strlen ("QPassSignals:") + 1);
      strcpy (pass_packet, "QPassSignals:");
      p = pass_packet + strlen (pass_packet);
      for (i = 0; i < numsigs; i++)
        {
          if (signal_stop_state (i) == 0
              && signal_print_state (i) == 0
              && signal_pass_state (i) == 1)
            {
              if (i >= 16)
                *p++ = tohex (i >> 4);
              *p++ = tohex (i & 15);
              if (count)
                *p++ = ';';
              else
                break;
              count--;
            }
        }
      *p = 0;
      if (!last_pass_packet || strcmp (last_pass_packet, pass_packet))
        {
          struct remote_state *rs = get_remote_state ();
          char *buf = rs->buf;

          putpkt (pass_packet);
          getpkt (&rs->buf, &rs->buf_size, 0);
          packet_ok (buf, &remote_protocol_packets[PACKET_QPassSignals]);
          if (last_pass_packet)
            xfree (last_pass_packet);
          last_pass_packet = pass_packet;
        }
      else
        xfree (pass_packet);
    }
}

/* If PTID is MAGIC_NULL_PTID, don't set any thread.  If PTID is
   MINUS_ONE_PTID, set the thread to -1, so the stub returns the
   thread.  If GEN is set, set the general thread, if not, then set
   the step/continue thread.  */
static void
set_thread (struct ptid ptid, int gen)
{
  struct remote_state *rs = get_remote_state ();
  ptid_t state = gen ? general_thread : continue_thread;
  char *buf = rs->buf;
  char *endbuf = rs->buf + get_remote_packet_size ();

  if (ptid_equal (state, ptid))
    return;

  *buf++ = 'H';
  *buf++ = gen ? 'g' : 'c';
  if (ptid_equal (ptid, magic_null_ptid))
    xsnprintf (buf, endbuf - buf, "0");
  else if (ptid_equal (ptid, any_thread_ptid))
    xsnprintf (buf, endbuf - buf, "0");
  else if (ptid_equal (ptid, minus_one_ptid))
    xsnprintf (buf, endbuf - buf, "-1");
  else
    write_ptid (buf, endbuf, ptid);
  putpkt (rs->buf);
  getpkt (&rs->buf, &rs->buf_size, 0);
  if (gen)
    general_thread = ptid;
  else
    continue_thread = ptid;
}

static void
set_general_thread (struct ptid ptid)
{
  set_thread (ptid, 1);
}

static void
set_continue_thread (struct ptid ptid)
{
  set_thread (ptid, 0);
}

/* Change the remote current process.  Which thread within the process
   ends up selected isn't important, as long as it is the same process
   as what INFERIOR_PTID points to.

   This comes from that fact that there is no explicit notion of
   "selected process" in the protocol.  The selected process for
   general operations is the process the selected general thread
   belongs to.  */

static void
set_general_process (void)
{
  struct remote_state *rs = get_remote_state ();

  /* If the remote can't handle multiple processes, don't bother.  */
  if (!remote_multi_process_p (rs))
    return;

  /* We only need to change the remote current thread if it's pointing
     at some other process.  */
  if (ptid_get_pid (general_thread) != ptid_get_pid (inferior_ptid))
    set_general_thread (inferior_ptid);
}

\f
/*  Return nonzero if the thread PTID is still alive on the remote
    system.  */

static int
remote_thread_alive (ptid_t ptid)
{
  struct remote_state *rs = get_remote_state ();
  int tid = ptid_get_tid (ptid);
  char *p, *endp;

  if (ptid_equal (ptid, magic_null_ptid))
    /* The main thread is always alive.  */
    return 1;

  if (ptid_get_pid (ptid) != 0 && ptid_get_tid (ptid) == 0)
    /* The main thread is always alive.  This can happen after a
       vAttach, if the remote side doesn't support
       multi-threading.  */
    return 1;

  p = rs->buf;
  endp = rs->buf + get_remote_packet_size ();

  *p++ = 'T';
  write_ptid (p, endp, ptid);

  putpkt (rs->buf);
  getpkt (&rs->buf, &rs->buf_size, 0);
  return (rs->buf[0] == 'O' && rs->buf[1] == 'K');
}

/* About these extended threadlist and threadinfo packets.  They are
   variable length packets but, the fields within them are often fixed
   length.  They are redundent enough to send over UDP as is the
   remote protocol in general.  There is a matching unit test module
   in libstub.  */

#define OPAQUETHREADBYTES 8

/* a 64 bit opaque identifier */
typedef unsigned char threadref[OPAQUETHREADBYTES];

/* WARNING: This threadref data structure comes from the remote O.S.,
   libstub protocol encoding, and remote.c. it is not particularly
   changable.  */

/* Right now, the internal structure is int. We want it to be bigger.
   Plan to fix this.
 */

typedef int gdb_threadref;      /* Internal GDB thread reference.  */

/* gdb_ext_thread_info is an internal GDB data structure which is
   equivalent to the reply of the remote threadinfo packet.  */

struct gdb_ext_thread_info
  {
    threadref threadid;         /* External form of thread reference.  */
    int active;                 /* Has state interesting to GDB?
                                   regs, stack.  */
    char display[256];          /* Brief state display, name,
                                   blocked/suspended.  */
    char shortname[32];         /* To be used to name threads.  */
    char more_display[256];     /* Long info, statistics, queue depth,
                                   whatever.  */
  };

/* The volume of remote transfers can be limited by submitting
   a mask containing bits specifying the desired information.
   Use a union of these values as the 'selection' parameter to
   get_thread_info. FIXME: Make these TAG names more thread specific.
 */

#define TAG_THREADID 1
#define TAG_EXISTS 2
#define TAG_DISPLAY 4
#define TAG_THREADNAME 8
#define TAG_MOREDISPLAY 16

#define BUF_THREAD_ID_SIZE (OPAQUETHREADBYTES * 2)

char *unpack_varlen_hex (char *buff, ULONGEST *result);

static char *unpack_nibble (char *buf, int *val);

static char *pack_nibble (char *buf, int nibble);

static char *pack_hex_byte (char *pkt, int /* unsigned char */ byte);

static char *unpack_byte (char *buf, int *value);

static char *pack_int (char *buf, int value);

static char *unpack_int (char *buf, int *value);

static char *unpack_string (char *src, char *dest, int length);

static char *pack_threadid (char *pkt, threadref *id);

static char *unpack_threadid (char *inbuf, threadref *id);

void int_to_threadref (threadref *id, int value);

static int threadref_to_int (threadref *ref);

static void copy_threadref (threadref *dest, threadref *src);

static int threadmatch (threadref *dest, threadref *src);

static char *pack_threadinfo_request (char *pkt, int mode,
                                      threadref *id);

static int remote_unpack_thread_info_response (char *pkt,
                                               threadref *expectedref,
                                               struct gdb_ext_thread_info
                                               *info);


static int remote_get_threadinfo (threadref *threadid,
                                  int fieldset, /*TAG mask */
                                  struct gdb_ext_thread_info *info);

static char *pack_threadlist_request (char *pkt, int startflag,
                                      int threadcount,
                                      threadref *nextthread);

static int parse_threadlist_response (char *pkt,
                                      int result_limit,
                                      threadref *original_echo,
                                      threadref *resultlist,
                                      int *doneflag);

static int remote_get_threadlist (int startflag,
                                  threadref *nextthread,
                                  int result_limit,
                                  int *done,
                                  int *result_count,
                                  threadref *threadlist);

typedef int (*rmt_thread_action) (threadref *ref, void *context);

static int remote_threadlist_iterator (rmt_thread_action stepfunction,
                                       void *context, int looplimit);

static int remote_newthread_step (threadref *ref, void *context);


/* Write a PTID to BUF.  ENDBUF points to one-passed-the-end of the
   buffer we're allowed to write to.  Returns
   BUF+CHARACTERS_WRITTEN.  */

static char *
write_ptid (char *buf, const char *endbuf, ptid_t ptid)
{
  int pid, tid;
  struct remote_state *rs = get_remote_state ();

  if (remote_multi_process_p (rs))
    {
      pid = ptid_get_pid (ptid);
      if (pid < 0)
        buf += xsnprintf (buf, endbuf - buf, "p-%x.", -pid);
      else
        buf += xsnprintf (buf, endbuf - buf, "p%x.", pid);
    }
  tid = ptid_get_tid (ptid);
  if (tid < 0)
    buf += xsnprintf (buf, endbuf - buf, "-%x", -tid);
  else
    buf += xsnprintf (buf, endbuf - buf, "%x", tid);

  return buf;
}

/* Extract a PTID from BUF.  If non-null, OBUF is set to the to one
   passed the last parsed char.  Returns null_ptid on error.  */

static ptid_t
read_ptid (char *buf, char **obuf)
{
  char *p = buf;
  char *pp;
  ULONGEST pid = 0, tid = 0;
  ptid_t ptid;

  if (*p == 'p')
    {
      /* Multi-process ptid.  */
      pp = unpack_varlen_hex (p + 1, &pid);
      if (*pp != '.')
        error (_("invalid remote ptid: %s\n"), p);

      p = pp;
      pp = unpack_varlen_hex (p + 1, &tid);
      if (obuf)
        *obuf = pp;
      return ptid_build (pid, 0, tid);
    }

  /* No multi-process.  Just a tid.  */
  pp = unpack_varlen_hex (p, &tid);

  /* Since the stub is not sending a process id, then default to
     what's in inferior_ptid.  */
  pid = ptid_get_pid (inferior_ptid);

  if (obuf)
    *obuf = pp;
  return ptid_build (pid, 0, tid);
}

/* Encode 64 bits in 16 chars of hex.  */

static const char hexchars[] = "0123456789abcdef";

static int
ishex (int ch, int *val)
{
  if ((ch >= 'a') && (ch <= 'f'))
    {
      *val = ch - 'a' + 10;
      return 1;
    }
  if ((ch >= 'A') && (ch <= 'F'))
    {
      *val = ch - 'A' + 10;
      return 1;
    }
  if ((ch >= '0') && (ch <= '9'))
    {
      *val = ch - '0';
      return 1;
    }
  return 0;
}

static int
stubhex (int ch)
{
  if (ch >= 'a' && ch <= 'f')
    return ch - 'a' + 10;
  if (ch >= '0' && ch <= '9')
    return ch - '0';
  if (ch >= 'A' && ch <= 'F')
    return ch - 'A' + 10;
  return -1;
}

static int
stub_unpack_int (char *buff, int fieldlength)
{
  int nibble;
  int retval = 0;

  while (fieldlength)
    {
      nibble = stubhex (*buff++);
      retval |= nibble;
      fieldlength--;
      if (fieldlength)
        retval = retval << 4;
    }
  return retval;
}

char *
unpack_varlen_hex (char *buff,  /* packet to parse */
                   ULONGEST *result)
{
  int nibble;
  ULONGEST retval = 0;

  while (ishex (*buff, &nibble))
    {
      buff++;
      retval = retval << 4;
      retval |= nibble & 0x0f;
    }
  *result = retval;
  return buff;
}

static char *
unpack_nibble (char *buf, int *val)
{
  *val = fromhex (*buf++);
  return buf;
}

static char *
pack_nibble (char *buf, int nibble)
{
  *buf++ = hexchars[(nibble & 0x0f)];
  return buf;
}

static char *
pack_hex_byte (char *pkt, int byte)
{
  *pkt++ = hexchars[(byte >> 4) & 0xf];
  *pkt++ = hexchars[(byte & 0xf)];
  return pkt;
}

static char *
unpack_byte (char *buf, int *value)
{
  *value = stub_unpack_int (buf, 2);
  return buf + 2;
}

static char *
pack_int (char *buf, int value)
{
  buf = pack_hex_byte (buf, (value >> 24) & 0xff);
  buf = pack_hex_byte (buf, (value >> 16) & 0xff);
  buf = pack_hex_byte (buf, (value >> 8) & 0x0ff);
  buf = pack_hex_byte (buf, (value & 0xff));
  return buf;
}

static char *
unpack_int (char *buf, int *value)
{
  *value = stub_unpack_int (buf, 8);
  return buf + 8;
}

#if 0                   /* Currently unused, uncomment when needed.  */
static char *pack_string (char *pkt, char *string);

static char *
pack_string (char *pkt, char *string)
{
  char ch;
  int len;

  len = strlen (string);
  if (len > 200)
    len = 200;          /* Bigger than most GDB packets, junk???  */
  pkt = pack_hex_byte (pkt, len);
  while (len-- > 0)
    {
      ch = *string++;
      if ((ch == '\0') || (ch == '#'))
        ch = '*';               /* Protect encapsulation.  */
      *pkt++ = ch;
    }
  return pkt;
}
#endif /* 0 (unused) */

static char *
unpack_string (char *src, char *dest, int length)
{
  while (length--)
    *dest++ = *src++;
  *dest = '\0';
  return src;
}

static char *
pack_threadid (char *pkt, threadref *id)
{
  char *limit;
  unsigned char *altid;

  altid = (unsigned char *) id;
  limit = pkt + BUF_THREAD_ID_SIZE;
  while (pkt < limit)
    pkt = pack_hex_byte (pkt, *altid++);
  return pkt;
}


static char *
unpack_threadid (char *inbuf, threadref *id)
{
  char *altref;
  char *limit = inbuf + BUF_THREAD_ID_SIZE;
  int x, y;

  altref = (char *) id;

  while (inbuf < limit)
    {
      x = stubhex (*inbuf++);
      y = stubhex (*inbuf++);
      *altref++ = (x << 4) | y;
    }
  return inbuf;
}

/* Externally, threadrefs are 64 bits but internally, they are still
   ints. This is due to a mismatch of specifications.  We would like
   to use 64bit thread references internally.  This is an adapter
   function.  */

void
int_to_threadref (threadref *id, int value)
{
  unsigned char *scan;

  scan = (unsigned char *) id;
  {
    int i = 4;
    while (i--)
      *scan++ = 0;
  }
  *scan++ = (value >> 24) & 0xff;
  *scan++ = (value >> 16) & 0xff;
  *scan++ = (value >> 8) & 0xff;
  *scan++ = (value & 0xff);
}

static int
threadref_to_int (threadref *ref)
{
  int i, value = 0;
  unsigned char *scan;

  scan = *ref;
  scan += 4;
  i = 4;
  while (i-- > 0)
    value = (value << 8) | ((*scan++) & 0xff);
  return value;
}

static void
copy_threadref (threadref *dest, threadref *src)
{
  int i;
  unsigned char *csrc, *cdest;

  csrc = (unsigned char *) src;
  cdest = (unsigned char *) dest;
  i = 8;
  while (i--)
    *cdest++ = *csrc++;
}

static int
threadmatch (threadref *dest, threadref *src)
{
  /* Things are broken right now, so just assume we got a match.  */
#if 0
  unsigned char *srcp, *destp;
  int i, result;
  srcp = (char *) src;
  destp = (char *) dest;

  result = 1;
  while (i-- > 0)
    result &= (*srcp++ == *destp++) ? 1 : 0;
  return result;
#endif
  return 1;
}

/*
   threadid:1,        # always request threadid
   context_exists:2,
   display:4,
   unique_name:8,
   more_display:16
 */

/* Encoding:  'Q':8,'P':8,mask:32,threadid:64 */

static char *
pack_threadinfo_request (char *pkt, int mode, threadref *id)
{
  *pkt++ = 'q';                         /* Info Query */
  *pkt++ = 'P';                         /* process or thread info */
  pkt = pack_int (pkt, mode);           /* mode */
  pkt = pack_threadid (pkt, id);        /* threadid */
  *pkt = '\0';                          /* terminate */
  return pkt;
}

/* These values tag the fields in a thread info response packet.  */
/* Tagging the fields allows us to request specific fields and to
   add more fields as time goes by.  */

#define TAG_THREADID 1          /* Echo the thread identifier.  */
#define TAG_EXISTS 2            /* Is this process defined enough to
                                   fetch registers and its stack?  */
#define TAG_DISPLAY 4           /* A short thing maybe to put on a window */
#define TAG_THREADNAME 8        /* string, maps 1-to-1 with a thread is.  */
#define TAG_MOREDISPLAY 16      /* Whatever the kernel wants to say about
                                   the process.  */

static int
remote_unpack_thread_info_response (char *pkt, threadref *expectedref,
                                    struct gdb_ext_thread_info *info)
{
  struct remote_state *rs = get_remote_state ();
  int mask, length;
  int tag;
  threadref ref;
  char *limit = pkt + rs->buf_size; /* Plausible parsing limit.  */
  int retval = 1;

  /* info->threadid = 0; FIXME: implement zero_threadref.  */
  info->active = 0;
  info->display[0] = '\0';
  info->shortname[0] = '\0';
  info->more_display[0] = '\0';

  /* Assume the characters indicating the packet type have been
     stripped.  */
  pkt = unpack_int (pkt, &mask);        /* arg mask */
  pkt = unpack_threadid (pkt, &ref);

  if (mask == 0)
    warning (_("Incomplete response to threadinfo request."));
  if (!threadmatch (&ref, expectedref))
    {                   /* This is an answer to a different request.  */
      warning (_("ERROR RMT Thread info mismatch."));
      return 0;
    }
  copy_threadref (&info->threadid, &ref);

  /* Loop on tagged fields , try to bail if somthing goes wrong.  */

  /* Packets are terminated with nulls.  */
  while ((pkt < limit) && mask && *pkt)
    {
      pkt = unpack_int (pkt, &tag);     /* tag */
      pkt = unpack_byte (pkt, &length); /* length */
      if (!(tag & mask))                /* Tags out of synch with mask.  */
        {
          warning (_("ERROR RMT: threadinfo tag mismatch."));
          retval = 0;
          break;
        }
      if (tag == TAG_THREADID)
        {
          if (length != 16)
            {
              warning (_("ERROR RMT: length of threadid is not 16."));
              retval = 0;
              break;
            }
          pkt = unpack_threadid (pkt, &ref);
          mask = mask & ~TAG_THREADID;
          continue;
        }
      if (tag == TAG_EXISTS)
        {
          info->active = stub_unpack_int (pkt, length);
          pkt += length;
          mask = mask & ~(TAG_EXISTS);
          if (length > 8)
            {
              warning (_("ERROR RMT: 'exists' length too long."));
              retval = 0;
              break;
            }
          continue;
        }
      if (tag == TAG_THREADNAME)
        {
          pkt = unpack_string (pkt, &info->shortname[0], length);
          mask = mask & ~TAG_THREADNAME;
          continue;
        }
      if (tag == TAG_DISPLAY)
        {
          pkt = unpack_string (pkt, &info->display[0], length);
          mask = mask & ~TAG_DISPLAY;
          continue;
        }
      if (tag == TAG_MOREDISPLAY)
        {
          pkt = unpack_string (pkt, &info->more_display[0], length);
          mask = mask & ~TAG_MOREDISPLAY;
          continue;
        }
      warning (_("ERROR RMT: unknown thread info tag."));
      break;                    /* Not a tag we know about.  */
    }
  return retval;
}

static int
remote_get_threadinfo (threadref *threadid, int fieldset,       /* TAG mask */
                       struct gdb_ext_thread_info *info)
{
  struct remote_state *rs = get_remote_state ();
  int result;

  pack_threadinfo_request (rs->buf, fieldset, threadid);
  putpkt (rs->buf);
  getpkt (&rs->buf, &rs->buf_size, 0);

  if (rs->buf[0] == '\0')
    return 0;

  result = remote_unpack_thread_info_response (rs->buf + 2,
                                               threadid, info);
  return result;
}

/*    Format: i'Q':8,i"L":8,initflag:8,batchsize:16,lastthreadid:32   */

static char *
pack_threadlist_request (char *pkt, int startflag, int threadcount,
                         threadref *nextthread)
{
  *pkt++ = 'q';                 /* info query packet */
  *pkt++ = 'L';                 /* Process LIST or threadLIST request */
  pkt = pack_nibble (pkt, startflag);           /* initflag 1 bytes */
  pkt = pack_hex_byte (pkt, threadcount);       /* threadcount 2 bytes */
  pkt = pack_threadid (pkt, nextthread);        /* 64 bit thread identifier */
  *pkt = '\0';
  return pkt;
}

/* Encoding:   'q':8,'M':8,count:16,done:8,argthreadid:64,(threadid:64)* */

static int
parse_threadlist_response (char *pkt, int result_limit,
                           threadref *original_echo, threadref *resultlist,
                           int *doneflag)
{
  struct remote_state *rs = get_remote_state ();
  char *limit;
  int count, resultcount, done;

  resultcount = 0;
  /* Assume the 'q' and 'M chars have been stripped.  */
  limit = pkt + (rs->buf_size - BUF_THREAD_ID_SIZE);
  /* done parse past here */
  pkt = unpack_byte (pkt, &count);      /* count field */
  pkt = unpack_nibble (pkt, &done);
  /* The first threadid is the argument threadid.  */
  pkt = unpack_threadid (pkt, original_echo);   /* should match query packet */
  while ((count-- > 0) && (pkt < limit))
    {
      pkt = unpack_threadid (pkt, resultlist++);
      if (resultcount++ >= result_limit)
        break;
    }
  if (doneflag)
    *doneflag = done;
  return resultcount;
}

static int
remote_get_threadlist (int startflag, threadref *nextthread, int result_limit,
                       int *done, int *result_count, threadref *threadlist)
{
  struct remote_state *rs = get_remote_state ();
  static threadref echo_nextthread;
  int result = 1;

  /* Trancate result limit to be smaller than the packet size.  */
  if ((((result_limit + 1) * BUF_THREAD_ID_SIZE) + 10) >= get_remote_packet_size ())
    result_limit = (get_remote_packet_size () / BUF_THREAD_ID_SIZE) - 2;

  pack_threadlist_request (rs->buf, startflag, result_limit, nextthread);
  putpkt (rs->buf);
  getpkt (&rs->buf, &rs->buf_size, 0);

  if (*rs->buf == '\0')
    *result_count = 0;
  else
    *result_count =
      parse_threadlist_response (rs->buf + 2, result_limit, &echo_nextthread,
                                 threadlist, done);

  if (!threadmatch (&echo_nextthread, nextthread))
    {
      /* FIXME: This is a good reason to drop the packet.  */
      /* Possably, there is a duplicate response.  */
      /* Possabilities :
         retransmit immediatly - race conditions
         retransmit after timeout - yes
         exit
         wait for packet, then exit
       */
      warning (_("HMM: threadlist did not echo arg thread, dropping it."));
      return 0;                 /* I choose simply exiting.  */
    }
  if (*result_count <= 0)
    {
      if (*done != 1)
        {
          warning (_("RMT ERROR : failed to get remote thread list."));
          result = 0;
        }
      return result;            /* break; */
    }
  if (*result_count > result_limit)
    {
      *result_count = 0;
      warning (_("RMT ERROR: threadlist response longer than requested."));
      return 0;
    }
  return result;
}

/* This is the interface between remote and threads, remotes upper
   interface.  */

/* remote_find_new_threads retrieves the thread list and for each
   thread in the list, looks up the thread in GDB's internal list,
   adding the thread if it does not already exist.  This involves
   getting partial thread lists from the remote target so, polling the
   quit_flag is required.  */


/* About this many threadisds fit in a packet.  */

#define MAXTHREADLISTRESULTS 32

static int
remote_threadlist_iterator (rmt_thread_action stepfunction, void *context,
                            int looplimit)
{
  int done, i, result_count;
  int startflag = 1;
  int result = 1;
  int loopcount = 0;
  static threadref nextthread;
  static threadref resultthreadlist[MAXTHREADLISTRESULTS];

  done = 0;
  while (!done)
    {
      if (loopcount++ > looplimit)
        {
          result = 0;
          warning (_("Remote fetch threadlist -infinite loop-."));
          break;
        }
      if (!remote_get_threadlist (startflag, &nextthread, MAXTHREADLISTRESULTS,
                                  &done, &result_count, resultthreadlist))
        {
          result = 0;
          break;
        }
      /* Clear for later iterations.  */
      startflag = 0;
      /* Setup to resume next batch of thread references, set nextthread.  */
      if (result_count >= 1)
        copy_threadref (&nextthread, &resultthreadlist[result_count - 1]);
      i = 0;
      while (result_count--)
        if (!(result = (*stepfunction) (&resultthreadlist[i++], context)))
          break;
    }
  return result;
}

static int
remote_newthread_step (threadref *ref, void *context)
{
  int pid = ptid_get_pid (inferior_ptid);
  ptid_t ptid = ptid_build (pid, 0, threadref_to_int (ref));

  if (!in_thread_list (ptid))
    add_thread (ptid);
  return 1;                     /* continue iterator */
}

#define CRAZY_MAX_THREADS 1000

static ptid_t
remote_current_thread (ptid_t oldpid)
{
  struct remote_state *rs = get_remote_state ();
  char *p = rs->buf;
  int tid;
  int pid;

  putpkt ("qC");
  getpkt (&rs->buf, &rs->buf_size, 0);
  if (rs->buf[0] == 'Q' && rs->buf[1] == 'C')
    return read_ptid (&rs->buf[2], NULL);
  else
    return oldpid;
}

/* Find new threads for info threads command.
 * Original version, using John Metzler's thread protocol.
 */

static void
remote_find_new_threads (void)
{
  remote_threadlist_iterator (remote_newthread_step, 0,
                              CRAZY_MAX_THREADS);
}

/*
 * Find all threads for info threads command.
 * Uses new thread protocol contributed by Cisco.
 * Falls back and attempts to use the older method (above)
 * if the target doesn't respond to the new method.
 */

static void
remote_threads_info (void)
{
  struct remote_state *rs = get_remote_state ();
  char *bufp;
  ptid_t new_thread;

  if (remote_desc == 0)         /* paranoia */
    error (_("Command can only be used when connected to the remote target."));

  if (use_threadinfo_query)
    {
      putpkt ("qfThreadInfo");
      getpkt (&rs->buf, &rs->buf_size, 0);
      bufp = rs->buf;
      if (bufp[0] != '\0')              /* q packet recognized */
        {
          while (*bufp++ == 'm')        /* reply contains one or more TID */
            {
              do
                {
                  new_thread = read_ptid (bufp, &bufp);
                  if (!ptid_equal (new_thread, null_ptid)
                      && (!in_thread_list (new_thread)
                          || is_exited (new_thread)))
                    {
                      /* When connected to a multi-process aware stub,
                         "info threads" may show up threads of
                         inferiors we didn't know about yet.  Add them
                         now, and before adding any of its child
                         threads, so notifications are emitted in a
                         sensible order.  */
                      if (!in_inferior_list (ptid_get_pid (new_thread)))
                        add_inferior (ptid_get_pid (new_thread));

                      add_thread (new_thread);

                      /* In non-stop mode, we assume new found threads
                         are running until we proven otherwise with a
                         stop reply.  In all-stop, we can only get
                         here if all threads are stopped.  */
                      set_executing (new_thread, non_stop ? 1 : 0);
                      set_running (new_thread, non_stop ? 1 : 0);
                    }
                }
              while (*bufp++ == ',');   /* comma-separated list */
              putpkt ("qsThreadInfo");
              getpkt (&rs->buf, &rs->buf_size, 0);
              bufp = rs->buf;
            }
          return;       /* done */
        }
    }

  /* Only qfThreadInfo is supported in non-stop mode.  */
  if (non_stop)
    return;

  /* Else fall back to old method based on jmetzler protocol.  */
  use_threadinfo_query = 0;
  remote_find_new_threads ();
  return;
}

/*
 * Collect a descriptive string about the given thread.
 * The target may say anything it wants to about the thread
 * (typically info about its blocked / runnable state, name, etc.).
 * This string will appear in the info threads display.
 *
 * Optional: targets are not required to implement this function.
 */

static char *
remote_threads_extra_info (struct thread_info *tp)
{
  struct remote_state *rs = get_remote_state ();
  int result;
  int set;
  threadref id;
  struct gdb_ext_thread_info threadinfo;
  static char display_buf[100]; /* arbitrary...  */
  int n = 0;                    /* position in display_buf */

  if (remote_desc == 0)         /* paranoia */
    internal_error (__FILE__, __LINE__,
                    _("remote_threads_extra_info"));

  if (ptid_equal (tp->ptid, magic_null_ptid)
      || (ptid_get_pid (tp->ptid) != 0 && ptid_get_tid (tp->ptid) == 0))
    /* This is the main thread which was added by GDB.  The remote
       server doesn't know about it.  */
    return NULL;

  if (use_threadextra_query)
    {
      char *b = rs->buf;
      char *endb = rs->buf + get_remote_packet_size ();

      xsnprintf (b, endb - b, "qThreadExtraInfo,");
      b += strlen (b);
      write_ptid (b, endb, tp->ptid);

      putpkt (rs->buf);
      getpkt (&rs->buf, &rs->buf_size, 0);
      if (rs->buf[0] != 0)
        {
          n = min (strlen (rs->buf) / 2, sizeof (display_buf));
          result = hex2bin (rs->buf, (gdb_byte *) display_buf, n);
          display_buf [result] = '\0';
          return display_buf;
        }
    }

  /* If the above query fails, fall back to the old method.  */
  use_threadextra_query = 0;
  set = TAG_THREADID | TAG_EXISTS | TAG_THREADNAME
    | TAG_MOREDISPLAY | TAG_DISPLAY;
  int_to_threadref (&id, ptid_get_tid (tp->ptid));
  if (remote_get_threadinfo (&id, set, &threadinfo))
    if (threadinfo.active)
      {
        if (*threadinfo.shortname)
          n += xsnprintf (&display_buf[0], sizeof (display_buf) - n,
                          " Name: %s,", threadinfo.shortname);
        if (*threadinfo.display)
          n += xsnprintf (&display_buf[n], sizeof (display_buf) - n,
                          " State: %s,", threadinfo.display);
        if (*threadinfo.more_display)
          n += xsnprintf (&display_buf[n], sizeof (display_buf) - n,
                          " Priority: %s", threadinfo.more_display);

        if (n > 0)
          {
            /* For purely cosmetic reasons, clear up trailing commas.  */
            if (',' == display_buf[n-1])
              display_buf[n-1] = ' ';
            return display_buf;
          }
      }
  return NULL;
}
\f

/* Restart the remote side; this is an extended protocol operation.  */

static void
extended_remote_restart (void)
{
  struct remote_state *rs = get_remote_state ();

  /* Send the restart command; for reasons I don't understand the
     remote side really expects a number after the "R".  */
  xsnprintf (rs->buf, get_remote_packet_size (), "R%x", 0);
  putpkt (rs->buf);

  remote_fileio_reset ();
}
\f
/* Clean up connection to a remote debugger.  */

static void
remote_close (int quitting)
{
  if (remote_desc == NULL)
    return; /* already closed */

  /* Make sure we leave stdin registered in the event loop, and we
     don't leave the async SIGINT signal handler installed.  */
  remote_terminal_ours ();

  serial_close (remote_desc);
  remote_desc = NULL;

  /* We don't have a connection to the remote stub anymore.  Get rid
     of all the inferiors and their threads we were controlling.  */
  discard_all_inferiors ();

  /* We're no longer interested in any of these events.  */
  discard_pending_stop_replies (-1);

  if (remote_async_inferior_event_token)
    delete_async_event_handler (&remote_async_inferior_event_token);
  if (remote_async_get_pending_events_token)
    delete_async_event_handler (&remote_async_get_pending_events_token);

  generic_mourn_inferior ();
}

/* Query the remote side for the text, data and bss offsets.  */

static void
get_offsets (void)
{
  struct remote_state *rs = get_remote_state ();
  char *buf;
  char *ptr;
  int lose, num_segments = 0, do_sections, do_segments;
  CORE_ADDR text_addr, data_addr, bss_addr, segments[2];
  struct section_offsets *offs;
  struct symfile_segment_data *data;

  if (symfile_objfile == NULL)
    return;

  putpkt ("qOffsets");
  getpkt (&rs->buf, &rs->buf_size, 0);
  buf = rs->buf;

  if (buf[0] == '\000')
    return;                     /* Return silently.  Stub doesn't support
                                   this command.  */
  if (buf[0] == 'E')
    {
      warning (_("Remote failure reply: %s"), buf);
      return;
    }

  /* Pick up each field in turn.  This used to be done with scanf, but
     scanf will make trouble if CORE_ADDR size doesn't match
     conversion directives correctly.  The following code will work
     with any size of CORE_ADDR.  */
  text_addr = data_addr = bss_addr = 0;
  ptr = buf;
  lose = 0;

  if (strncmp (ptr, "Text=", 5) == 0)
    {
      ptr += 5;
      /* Don't use strtol, could lose on big values.  */
      while (*ptr && *ptr != ';')
        text_addr = (text_addr << 4) + fromhex (*ptr++);

      if (strncmp (ptr, ";Data=", 6) == 0)
        {
          ptr += 6;
          while (*ptr && *ptr != ';')
            data_addr = (data_addr << 4) + fromhex (*ptr++);
        }
      else
        lose = 1;

      if (!lose && strncmp (ptr, ";Bss=", 5) == 0)
        {
          ptr += 5;
          while (*ptr && *ptr != ';')
            bss_addr = (bss_addr << 4) + fromhex (*ptr++);

          if (bss_addr != data_addr)
            warning (_("Target reported unsupported offsets: %s"), buf);
        }
      else
        lose = 1;
    }
  else if (strncmp (ptr, "TextSeg=", 8) == 0)
    {
      ptr += 8;
      /* Don't use strtol, could lose on big values.  */
      while (*ptr && *ptr != ';')
        text_addr = (text_addr << 4) + fromhex (*ptr++);
      num_segments = 1;

      if (strncmp (ptr, ";DataSeg=", 9) == 0)
        {
          ptr += 9;
          while (*ptr && *ptr != ';')
            data_addr = (data_addr << 4) + fromhex (*ptr++);
          num_segments++;
        }
    }
  else
    lose = 1;

  if (lose)
    error (_("Malformed response to offset query, %s"), buf);
  else if (*ptr != '\0')
    warning (_("Target reported unsupported offsets: %s"), buf);

  offs = ((struct section_offsets *)
          alloca (SIZEOF_N_SECTION_OFFSETS (symfile_objfile->num_sections)));
  memcpy (offs, symfile_objfile->section_offsets,
          SIZEOF_N_SECTION_OFFSETS (symfile_objfile->num_sections));

  data = get_symfile_segment_data (symfile_objfile->obfd);
  do_segments = (data != NULL);
  do_sections = num_segments == 0;

  if (num_segments > 0)
    {
      segments[0] = text_addr;
      segments[1] = data_addr;
    }
  /* If we have two segments, we can still try to relocate everything
     by assuming that the .text and .data offsets apply to the whole
     text and data segments.  Convert the offsets given in the packet
     to base addresses for symfile_map_offsets_to_segments.  */
  else if (data && data->num_segments == 2)
    {
      segments[0] = data->segment_bases[0] + text_addr;
      segments[1] = data->segment_bases[1] + data_addr;
      num_segments = 2;
    }
  /* If the object file has only one segment, assume that it is text
     rather than data; main programs with no writable data are rare,
     but programs with no code are useless.  Of course the code might
     have ended up in the data segment... to detect that we would need
     the permissions here.  */
  else if (data && data->num_segments == 1)
    {
      segments[0] = data->segment_bases[0] + text_addr;
      num_segments = 1;
    }
  /* There's no way to relocate by segment.  */
  else
    do_segments = 0;

  if (do_segments)
    {
      int ret = symfile_map_offsets_to_segments (symfile_objfile->obfd, data,
                                                 offs, num_segments, segments);

      if (ret == 0 && !do_sections)
        error (_("Can not handle qOffsets TextSeg response with this symbol file"));

      if (ret > 0)
        do_sections = 0;
    }

  if (data)
    free_symfile_segment_data (data);

  if (do_sections)
    {
      offs->offsets[SECT_OFF_TEXT (symfile_objfile)] = text_addr;

      /* This is a temporary kludge to force data and bss to use the same offsets
         because that's what nlmconv does now.  The real solution requires changes
         to the stub and remote.c that I don't have time to do right now.  */

      offs->offsets[SECT_OFF_DATA (symfile_objfile)] = data_addr;
      offs->offsets[SECT_OFF_BSS (symfile_objfile)] = data_addr;
    }

  objfile_relocate (symfile_objfile, offs);
}

/* Callback for iterate_over_threads.  Set the STOP_REQUESTED flags in
   threads we know are stopped already.  This is used during the
   initial remote connection in non-stop mode --- threads that are
   reported as already being stopped are left stopped.  */

static int
set_stop_requested_callback (struct thread_info *thread, void *data)
{
  /* If we have a stop reply for this thread, it must be stopped.  */
  if (peek_stop_reply (thread->ptid))
    set_stop_requested (thread->ptid, 1);

  return 0;
}

/* Stub for catch_exception.  */

struct start_remote_args
{
  int from_tty;

  /* The current target.  */
  struct target_ops *target;

  /* Non-zero if this is an extended-remote target.  */
  int extended_p;
};

static void
remote_start_remote (struct ui_out *uiout, void *opaque)
{
  struct start_remote_args *args = opaque;
  struct remote_state *rs = get_remote_state ();
  struct packet_config *noack_config;
  char *wait_status = NULL;

  immediate_quit++;             /* Allow user to interrupt it.  */

  /* Ack any packet which the remote side has already sent.  */
  serial_write (remote_desc, "+", 1);

  /* The first packet we send to the target is the optional "supported
     packets" request.  If the target can answer this, it will tell us
     which later probes to skip.  */
  remote_query_supported ();

  /* Next, we possibly activate noack mode.

     If the QStartNoAckMode packet configuration is set to AUTO,
     enable noack mode if the stub reported a wish for it with
     qSupported.

     If set to TRUE, then enable noack mode even if the stub didn't
     report it in qSupported.  If the stub doesn't reply OK, the
     session ends with an error.

     If FALSE, then don't activate noack mode, regardless of what the
     stub claimed should be the default with qSupported.  */

  noack_config = &remote_protocol_packets[PACKET_QStartNoAckMode];

  if (noack_config->detect == AUTO_BOOLEAN_TRUE
      || (noack_config->detect == AUTO_BOOLEAN_AUTO
          && noack_config->support == PACKET_ENABLE))
    {
      putpkt ("QStartNoAckMode");
      getpkt (&rs->buf, &rs->buf_size, 0);
      if (packet_ok (rs->buf, noack_config) == PACKET_OK)
        rs->noack_mode = 1;
    }

  if (args->extended_p)
    {
      /* Tell the remote that we are using the extended protocol.  */
      putpkt ("!");
      getpkt (&rs->buf, &rs->buf_size, 0);
    }

  /* On OSs where the list of libraries is global to all
     processes, we fetch them early.  */
  if (gdbarch_has_global_solist (target_gdbarch))
    solib_add (NULL, args->from_tty, args->target, auto_solib_add);

  /* Next, if the target can specify a description, read it.  We do
     this before anything involving memory or registers.  */
  target_find_description ();

  if (non_stop)
    {
      if (!rs->non_stop_aware)
        error (_("Non-stop mode requested, but remote does not support non-stop"));

      putpkt ("QNonStop:1");
      getpkt (&rs->buf, &rs->buf_size, 0);

      if (strcmp (rs->buf, "OK") != 0)
        error ("Remote refused setting non-stop mode with: %s", rs->buf);

      /* Find about threads and processes the stub is already
         controlling.  We default to adding them in the running state.
         The '?' query below will then tell us about which threads are
         stopped.  */

      /* If we're not using the multi-process extensions, there's no
         way to know the pid of the reported threads; use the magic
         number.  */
      if (!remote_multi_process_p (rs))
        inferior_ptid = magic_null_ptid;

      remote_threads_info ();
    }
  else if (rs->non_stop_aware)
    {
      /* Don't assume that the stub can operate in all-stop mode.
         Request it explicitely.  */
      putpkt ("QNonStop:0");
      getpkt (&rs->buf, &rs->buf_size, 0);

      if (strcmp (rs->buf, "OK") != 0)
        error ("Remote refused setting all-stop mode with: %s", rs->buf);
    }

  /* Check whether the target is running now.  */
  putpkt ("?");
  getpkt (&rs->buf, &rs->buf_size, 0);

  if (!non_stop)
    {
      if (rs->buf[0] == 'W' || rs->buf[0] == 'X')
        {
          if (args->extended_p)
            {
              /* We're connected, but not running.  Drop out before we
                 call start_remote.  */
              target_mark_exited (args->target);
              return;
            }
          else
            error (_("The target is not running (try extended-remote?)"));
        }
      else
        {
          if (args->extended_p)
            target_mark_running (args->target);

          /* Save the reply for later.  */
          wait_status = alloca (strlen (rs->buf) + 1);
          strcpy (wait_status, rs->buf);
        }

      /* Let the stub know that we want it to return the thread.  */
      set_continue_thread (minus_one_ptid);

      /* Without this, some commands which require an active target
         (such as kill) won't work.  This variable serves (at least)
         double duty as both the pid of the target process (if it has
         such), and as a flag indicating that a target is active.
         These functions should be split out into seperate variables,
         especially since GDB will someday have a notion of debugging
         several processes.  */
      inferior_ptid = magic_null_ptid;

      /* Now, if we have thread information, update inferior_ptid.  */
      inferior_ptid = remote_current_thread (inferior_ptid);

      add_inferior (ptid_get_pid (inferior_ptid));

      /* Always add the main thread.  */
      add_thread_silent (inferior_ptid);

      get_offsets ();           /* Get text, data & bss offsets.  */

      /* Use the previously fetched status.  */
      gdb_assert (wait_status != NULL);
      strcpy (rs->buf, wait_status);
      rs->cached_wait_status = 1;

      immediate_quit--;
      start_remote (args->from_tty); /* Initialize gdb process mechanisms.  */
    }
  else
    {
      /* In non-stop, we will either get an "OK", meaning that there
         are no stopped threads at this time; or, a regular stop
         reply.  In the latter case, there may be more than one thread
         stopped --- we pull them all out using the vStopped
         mechanism.  */
      if (strcmp (rs->buf, "OK") != 0)
        {
          struct stop_reply *stop_reply;
          struct cleanup *old_chain;

          stop_reply = stop_reply_xmalloc ();
          old_chain = make_cleanup (do_stop_reply_xfree, stop_reply);

          remote_parse_stop_reply (rs->buf, stop_reply);
          discard_cleanups (old_chain);

          /* get_pending_stop_replies acks this one, and gets the rest
             out.  */
          pending_stop_reply = stop_reply;
          remote_get_pending_stop_replies ();

          /* Make sure that threads that were stopped remain
             stopped.  */
          iterate_over_threads (set_stop_requested_callback, NULL);
        }

      if (target_can_async_p ())
        target_async (inferior_event_handler, 0);

      if (thread_count () == 0)
        {
          if (args->extended_p)
            {
              /* We're connected, but not running.  Drop out before we
                 call start_remote.  */
              target_mark_exited (args->target);
              return;
            }
          else
            error (_("The target is not running (try extended-remote?)"));
        }

      if (args->extended_p)
        target_mark_running (args->target);

      /* Let the stub know that we want it to return the thread.  */

      /* Force the stub to choose a thread.  */
      set_general_thread (null_ptid);

      /* Query it.  */
      inferior_ptid = remote_current_thread (minus_one_ptid);
      if (ptid_equal (inferior_ptid, minus_one_ptid))
        error (_("remote didn't report the current thread in non-stop mode"));

      get_offsets ();           /* Get text, data & bss offsets.  */

      /* In non-stop mode, any cached wait status will be stored in
         the stop reply queue.  */
      gdb_assert (wait_status == NULL);
    }

  /* If we connected to a live target, do some additional setup.  */
  if (target_has_execution)
    {
      if (exec_bfd)     /* No use without an exec file.  */
        remote_check_symbols (symfile_objfile);
    }

  /* If code is shared between processes, then breakpoints are global
     too; Insert them now.  */
  if (gdbarch_has_global_solist (target_gdbarch)
      && breakpoints_always_inserted_mode ())
    insert_breakpoints ();
}

/* Open a connection to a remote debugger.
   NAME is the filename used for communication.  */

static void
remote_open (char *name, int from_tty)
{
  remote_open_1 (name, from_tty, &remote_ops, 0);
}

/* Open a connection to a remote debugger using the extended
   remote gdb protocol.  NAME is the filename used for communication.  */

static void
extended_remote_open (char *name, int from_tty)
{
  remote_open_1 (name, from_tty, &extended_remote_ops, 1 /*extended_p */);
}

/* Generic code for opening a connection to a remote target.  */

static void
init_all_packet_configs (void)
{
  int i;
  for (i = 0; i < PACKET_MAX; i++)
    update_packet_config (&remote_protocol_packets[i]);
}

/* Symbol look-up.  */

static void
remote_check_symbols (struct objfile *objfile)
{
  struct remote_state *rs = get_remote_state ();
  char *msg, *reply, *tmp;
  struct minimal_symbol *sym;
  int end;

  if (remote_protocol_packets[PACKET_qSymbol].support == PACKET_DISABLE)
    return;

  /* Make sure the remote is pointing at the right process.  */
  set_general_process ();

  /* Allocate a message buffer.  We can't reuse the input buffer in RS,
     because we need both at the same time.  */
  msg = alloca (get_remote_packet_size ());

  /* Invite target to request symbol lookups.  */

  putpkt ("qSymbol::");
  getpkt (&rs->buf, &rs->buf_size, 0);
  packet_ok (rs->buf, &remote_protocol_packets[PACKET_qSymbol]);
  reply = rs->buf;

  while (strncmp (reply, "qSymbol:", 8) == 0)
    {
      tmp = &reply[8];
      end = hex2bin (tmp, (gdb_byte *) msg, strlen (tmp) / 2);
      msg[end] = '\0';
      sym = lookup_minimal_symbol (msg, NULL, NULL);
      if (sym == NULL)
        xsnprintf (msg, get_remote_packet_size (), "qSymbol::%s", &reply[8]);
      else
        {
          CORE_ADDR sym_addr = SYMBOL_VALUE_ADDRESS (sym);

          /* If this is a function address, return the start of code
             instead of any data function descriptor.  */
          sym_addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch,
                                                         sym_addr,
                                                         &current_target);

          xsnprintf (msg, get_remote_packet_size (), "qSymbol:%s:%s",
                     paddr_nz (sym_addr), &reply[8]);
        }
  
      putpkt (msg);
      getpkt (&rs->buf, &rs->buf_size, 0);
      reply = rs->buf;
    }
}

static struct serial *
remote_serial_open (char *name)
{
  static int udp_warning = 0;

  /* FIXME: Parsing NAME here is a hack.  But we want to warn here instead
     of in ser-tcp.c, because it is the remote protocol assuming that the
     serial connection is reliable and not the serial connection promising
     to be.  */
  if (!udp_warning && strncmp (name, "udp:", 4) == 0)
    {
      warning (_("\
The remote protocol may be unreliable over UDP.\n\
Some events may be lost, rendering further debugging impossible."));
      udp_warning = 1;
    }

  return serial_open (name);
}

/* This type describes each known response to the qSupported
   packet.  */
struct protocol_feature
{
  /* The name of this protocol feature.  */
  const char *name;

  /* The default for this protocol feature.  */
  enum packet_support default_support;

  /* The function to call when this feature is reported, or after
     qSupported processing if the feature is not supported.
     The first argument points to this structure.  The second
     argument indicates whether the packet requested support be
     enabled, disabled, or probed (or the default, if this function
     is being called at the end of processing and this feature was
     not reported).  The third argument may be NULL; if not NULL, it
     is a NUL-terminated string taken from the packet following
     this feature's name and an equals sign.  */
  void (*func) (const struct protocol_feature *, enum packet_support,
                const char *);

  /* The corresponding packet for this feature.  Only used if
     FUNC is remote_supported_packet.  */
  int packet;
};

static void
remote_supported_packet (const struct protocol_feature *feature,
                         enum packet_support support,
                         const char *argument)
{
  if (argument)
    {
      warning (_("Remote qSupported response supplied an unexpected value for"
                 " \"%s\"."), feature->name);
      return;
    }

  if (remote_protocol_packets[feature->packet].support
      == PACKET_SUPPORT_UNKNOWN)
    remote_protocol_packets[feature->packet].support = support;
}

static void
remote_packet_size (const struct protocol_feature *feature,
                    enum packet_support support, const char *value)
{
  struct remote_state *rs = get_remote_state ();

  int packet_size;
  char *value_end;

  if (support != PACKET_ENABLE)
    return;

  if (value == NULL || *value == '\0')
    {
      warning (_("Remote target reported \"%s\" without a size."),
               feature->name);
      return;
    }

  errno = 0;
  packet_size = strtol (value, &value_end, 16);
  if (errno != 0 || *value_end != '\0' || packet_size < 0)
    {
      warning (_("Remote target reported \"%s\" with a bad size: \"%s\"."),
               feature->name, value);
      return;
    }

  if (packet_size > MAX_REMOTE_PACKET_SIZE)
    {
      warning (_("limiting remote suggested packet size (%d bytes) to %d"),
               packet_size, MAX_REMOTE_PACKET_SIZE);
      packet_size = MAX_REMOTE_PACKET_SIZE;
    }

  /* Record the new maximum packet size.  */
  rs->explicit_packet_size = packet_size;
}

static void
remote_multi_process_feature (const struct protocol_feature *feature,
                              enum packet_support support, const char *value)
{
  struct remote_state *rs = get_remote_state ();
  rs->multi_process_aware = (support == PACKET_ENABLE);
}

static void
remote_non_stop_feature (const struct protocol_feature *feature,
                              enum packet_support support, const char *value)
{
  struct remote_state *rs = get_remote_state ();
  rs->non_stop_aware = (support == PACKET_ENABLE);
}

static struct protocol_feature remote_protocol_features[] = {
  { "PacketSize", PACKET_DISABLE, remote_packet_size, -1 },
  { "qXfer:auxv:read", PACKET_DISABLE, remote_supported_packet,
    PACKET_qXfer_auxv },
  { "qXfer:features:read", PACKET_DISABLE, remote_supported_packet,
    PACKET_qXfer_features },
  { "qXfer:libraries:read", PACKET_DISABLE, remote_supported_packet,
    PACKET_qXfer_libraries },
  { "qXfer:memory-map:read", PACKET_DISABLE, remote_supported_packet,
    PACKET_qXfer_memory_map },
  { "qXfer:spu:read", PACKET_DISABLE, remote_supported_packet,
    PACKET_qXfer_spu_read },
  { "qXfer:spu:write", PACKET_DISABLE, remote_supported_packet,
    PACKET_qXfer_spu_write },
  { "QPassSignals", PACKET_DISABLE, remote_supported_packet,
    PACKET_QPassSignals },
  { "QStartNoAckMode", PACKET_DISABLE, remote_supported_packet,
    PACKET_QStartNoAckMode },
  { "multiprocess", PACKET_DISABLE, remote_multi_process_feature, -1 },
  { "QNonStop", PACKET_DISABLE, remote_non_stop_feature, -1 },
};

static void
remote_query_supported (void)
{
  struct remote_state *rs = get_remote_state ();
  char *next;
  int i;
  unsigned char seen [ARRAY_SIZE (remote_protocol_features)];

  /* The packet support flags are handled differently for this packet
     than for most others.  We treat an error, a disabled packet, and
     an empty response identically: any features which must be reported
     to be used will be automatically disabled.  An empty buffer
     accomplishes this, since that is also the representation for a list
     containing no features.  */

  rs->buf[0] = 0;
  if (remote_protocol_packets[PACKET_qSupported].support != PACKET_DISABLE)
    {
      if (rs->extended)
        putpkt ("qSupported:multiprocess+");
      else
        putpkt ("qSupported");

      getpkt (&rs->buf, &rs->buf_size, 0);

      /* If an error occured, warn, but do not return - just reset the
         buffer to empty and go on to disable features.  */
      if (packet_ok (rs->buf, &remote_protocol_packets[PACKET_qSupported])
          == PACKET_ERROR)
        {
          warning (_("Remote failure reply: %s"), rs->buf);
          rs->buf[0] = 0;
        }
    }

  memset (seen, 0, sizeof (seen));

  next = rs->buf;
  while (*next)
    {
      enum packet_support is_supported;
      char *p, *end, *name_end, *value;

      /* First separate out this item from the rest of the packet.  If
         there's another item after this, we overwrite the separator
         (terminated strings are much easier to work with).  */
      p = next;
      end = strchr (p, ';');
      if (end == NULL)
        {
          end = p + strlen (p);
          next = end;
        }
      else
        {
          *end = '\0';
          next = end + 1;

          if (end == p)
            {
              warning (_("empty item in \"qSupported\" response"));
              continue;
            }
        }

      name_end = strchr (p, '=');
      if (name_end)
        {
          /* This is a name=value entry.  */
          is_supported = PACKET_ENABLE;
          value = name_end + 1;
          *name_end = '\0';
        }
      else
        {
          value = NULL;
          switch (end[-1])
            {
            case '+':
              is_supported = PACKET_ENABLE;
              break;

            case '-':
              is_supported = PACKET_DISABLE;
              break;

            case '?':
              is_supported = PACKET_SUPPORT_UNKNOWN;
              break;

            default:
              warning (_("unrecognized item \"%s\" in \"qSupported\" response"), p);
              continue;
            }
          end[-1] = '\0';
        }

      for (i = 0; i < ARRAY_SIZE (remote_protocol_features); i++)
        if (strcmp (remote_protocol_features[i].name, p) == 0)
          {
            const struct protocol_feature *feature;

            seen[i] = 1;
            feature = &remote_protocol_features[i];
            feature->func (feature, is_supported, value);
            break;
          }
    }

  /* If we increased the packet size, make sure to increase the global
     buffer size also.  We delay this until after parsing the entire
     qSupported packet, because this is the same buffer we were
     parsing.  */
  if (rs->buf_size < rs->explicit_packet_size)
    {
      rs->buf_size = rs->explicit_packet_size;
      rs->buf = xrealloc (rs->buf, rs->buf_size);
    }

  /* Handle the defaults for unmentioned features.  */
  for (i = 0; i < ARRAY_SIZE (remote_protocol_features); i++)
    if (!seen[i])
      {
        const struct protocol_feature *feature;

        feature = &remote_protocol_features[i];
        feature->func (feature, feature->default_support, NULL);
      }
}


static void
remote_open_1 (char *name, int from_tty, struct target_ops *target, int extended_p)
{
  struct remote_state *rs = get_remote_state ();

  if (name == 0)
    error (_("To open a remote debug connection, you need to specify what\n"
           "serial device is attached to the remote system\n"
           "(e.g. /dev/ttyS0, /dev/ttya, COM1, etc.)."));

  /* See FIXME above.  */
  if (!target_async_permitted)
    wait_forever_enabled_p = 1;

  /* If we're connected to a running target, target_preopen will kill it.
     But if we're connected to a target system with no running process,
     then we will still be connected when it returns.  Ask this question
     first, before target_preopen has a chance to kill anything.  */
  if (remote_desc != NULL && !target_has_execution)
    {
      if (!from_tty
          || query (_("Already connected to a remote target.  Disconnect? ")))
        pop_target ();
      else
        error (_("Still connected."));
    }

  target_preopen (from_tty);

  unpush_target (target);

  /* This time without a query.  If we were connected to an
     extended-remote target and target_preopen killed the running
     process, we may still be connected.  If we are starting "target
     remote" now, the extended-remote target will not have been
     removed by unpush_target.  */
  if (remote_desc != NULL && !target_has_execution)
    pop_target ();

  /* Make sure we send the passed signals list the next time we resume.  */
  xfree (last_pass_packet);
  last_pass_packet = NULL;

  remote_fileio_reset ();
  reopen_exec_file ();
  reread_symbols ();

  remote_desc = remote_serial_open (name);
  if (!remote_desc)
    perror_with_name (name);

  if (baud_rate != -1)
    {
      if (serial_setbaudrate (remote_desc, baud_rate))
        {
          /* The requested speed could not be set.  Error out to
             top level after closing remote_desc.  Take care to
             set remote_desc to NULL to avoid closing remote_desc
             more than once.  */
          serial_close (remote_desc);
          remote_desc = NULL;
          perror_with_name (name);
        }
    }

  serial_raw (remote_desc);

  /* If there is something sitting in the buffer we might take it as a
     response to a command, which would be bad.  */
  serial_flush_input (remote_desc);

  if (from_tty)
    {
      puts_filtered ("Remote debugging using ");
      puts_filtered (name);
      puts_filtered ("\n");
    }
  push_target (target);         /* Switch to using remote target now.  */

  /* Assume that the target is running, unless we learn otherwise.  */
  target_mark_running (target);

  /* Register extra event sources in the event loop.  */
  remote_async_inferior_event_token
    = create_async_event_handler (remote_async_inferior_event_handler,
                                  NULL);
  remote_async_get_pending_events_token
    = create_async_event_handler (remote_async_get_pending_events_handler,
                                  NULL);

  /* Reset the target state; these things will be queried either by
     remote_query_supported or as they are needed.  */
  init_all_packet_configs ();
  rs->cached_wait_status = 0;
  rs->explicit_packet_size = 0;
  rs->noack_mode = 0;
  rs->multi_process_aware = 0;
  rs->extended = extended_p;
  rs->non_stop_aware = 0;
  rs->waiting_for_stop_reply = 0;

  general_thread = not_sent_ptid;
  continue_thread = not_sent_ptid;

  /* Probe for ability to use "ThreadInfo" query, as required.  */
  use_threadinfo_query = 1;
  use_threadextra_query = 1;

  if (target_async_permitted)
    {
      /* With this target we start out by owning the terminal.  */
      remote_async_terminal_ours_p = 1;

      /* FIXME: cagney/1999-09-23: During the initial connection it is
         assumed that the target is already ready and able to respond to
         requests. Unfortunately remote_start_remote() eventually calls
         wait_for_inferior() with no timeout.  wait_forever_enabled_p gets
         around this. Eventually a mechanism that allows
         wait_for_inferior() to expect/get timeouts will be
         implemented.  */
      wait_forever_enabled_p = 0;
    }

  /* First delete any symbols previously loaded from shared libraries.  */
  no_shared_libraries (NULL, 0);

  /* Start afresh.  */
  init_thread_list ();

  /* Start the remote connection.  If error() or QUIT, discard this
     target (we'd otherwise be in an inconsistent state) and then
     propogate the error on up the exception chain.  This ensures that
     the caller doesn't stumble along blindly assuming that the
     function succeeded.  The CLI doesn't have this problem but other
     UI's, such as MI do.

     FIXME: cagney/2002-05-19: Instead of re-throwing the exception,
     this function should return an error indication letting the
     caller restore the previous state.  Unfortunately the command
     ``target remote'' is directly wired to this function making that
     impossible.  On a positive note, the CLI side of this problem has
     been fixed - the function set_cmd_context() makes it possible for
     all the ``target ....'' commands to share a common callback
     function.  See cli-dump.c.  */
  {
    struct gdb_exception ex;
    struct start_remote_args args;

    args.from_tty = from_tty;
    args.target = target;
    args.extended_p = extended_p;

    ex = catch_exception (uiout, remote_start_remote, &args, RETURN_MASK_ALL);
    if (ex.reason < 0)
      {
        /* Pop the partially set up target - unless something else did
           already before throwing the exception.  */
        if (remote_desc != NULL)
          pop_target ();
        if (target_async_permitted)
          wait_forever_enabled_p = 1;
        throw_exception (ex);
      }
  }

  if (target_async_permitted)
    wait_forever_enabled_p = 1;
}

/* This takes a program previously attached to and detaches it.  After
   this is done, GDB can be used to debug some other program.  We
   better not have left any breakpoints in the target program or it'll
   die when it hits one.  */

static void
remote_detach_1 (char *args, int from_tty, int extended)
{
  int pid = ptid_get_pid (inferior_ptid);
  struct remote_state *rs = get_remote_state ();

  if (args)
    error (_("Argument given to \"detach\" when remotely debugging."));

  if (!target_has_execution)
    error (_("No process to detach from."));

  /* Tell the remote target to detach.  */
  if (remote_multi_process_p (rs))
    sprintf (rs->buf, "D;%x", pid);
  else
    strcpy (rs->buf, "D");

  putpkt (rs->buf);
  getpkt (&rs->buf, &rs->buf_size, 0);

  if (rs->buf[0] == 'O' && rs->buf[1] == 'K')
    ;
  else if (rs->buf[0] == '\0')
    error (_("Remote doesn't know how to detach"));
  else
    error (_("Can't detach process."));

  if (from_tty)
    {
      if (remote_multi_process_p (rs))
        printf_filtered (_("Detached from remote %s.\n"),
                         target_pid_to_str (pid_to_ptid (pid)));
      else
        {
          if (extended)
            puts_filtered (_("Detached from remote process.\n"));
          else
            puts_filtered (_("Ending remote debugging.\n"));
        }
    }

  discard_pending_stop_replies (pid);
  detach_inferior (pid);
  target_mourn_inferior ();
}

static void
remote_detach (struct target_ops *ops, char *args, int from_tty)
{
  remote_detach_1 (args, from_tty, 0);
}

static void
extended_remote_detach (struct target_ops *ops, char *args, int from_tty)
{
  remote_detach_1 (args, from_tty, 1);
}

/* Same as remote_detach, but don't send the "D" packet; just disconnect.  */

static void
remote_disconnect (struct target_ops *target, char *args, int from_tty)
{
  if (args)
    error (_("Argument given to \"disconnect\" when remotely debugging."));

  /* Make sure we unpush even the extended remote targets; mourn
     won't do it.  So call remote_mourn_1 directly instead of
     target_mourn_inferior.  */
  remote_mourn_1 (target);

  if (from_tty)
    puts_filtered ("Ending remote debugging.\n");
}

/* Attach to the process specified by ARGS.  If FROM_TTY is non-zero,
   be chatty about it.  */

static void
extended_remote_attach_1 (struct target_ops *target, char *args, int from_tty)
{
  struct remote_state *rs = get_remote_state ();
  int pid;
  char *dummy;
  char *wait_status = NULL;
  struct inferior *inf;

  if (!args)
    error_no_arg (_("process-id to attach"));

  dummy = args;
  pid = strtol (args, &dummy, 0);
  /* Some targets don't set errno on errors, grrr!  */
  if (pid == 0 && args == dummy)
    error (_("Illegal process-id: %s."), args);

  if (remote_protocol_packets[PACKET_vAttach].support == PACKET_DISABLE)
    error (_("This target does not support attaching to a process"));

  sprintf (rs->buf, "vAttach;%x", pid);
  putpkt (rs->buf);
  getpkt (&rs->buf, &rs->buf_size, 0);

  if (packet_ok (rs->buf, &remote_protocol_packets[PACKET_vAttach]) == PACKET_OK)
    {
      if (from_tty)
        printf_unfiltered (_("Attached to %s\n"),
                           target_pid_to_str (pid_to_ptid (pid)));

      if (!non_stop)
        {
          /* Save the reply for later.  */
          wait_status = alloca (strlen (rs->buf) + 1);
          strcpy (wait_status, rs->buf);
        }
      else if (strcmp (rs->buf, "OK") != 0)
        error (_("Attaching to %s failed with: %s"),
               target_pid_to_str (pid_to_ptid (pid)),
               rs->buf);
    }
  else if (remote_protocol_packets[PACKET_vAttach].support == PACKET_DISABLE)
    error (_("This target does not support attaching to a process"));
  else
    error (_("Attaching to %s failed"),
           target_pid_to_str (pid_to_ptid (pid)));

  target_mark_running (target);
  inferior_ptid = pid_to_ptid (pid);

  /* Now, if we have thread information, update inferior_ptid.  */
  inferior_ptid = remote_current_thread (inferior_ptid);

  inf = add_inferior (pid);
  inf->attach_flag = 1;

  if (non_stop)
    /* Get list of threads.  */
    remote_threads_info ();
  else
    /* Add the main thread to the thread list.  */
    add_thread_silent (inferior_ptid);

  /* Next, if the target can specify a description, read it.  We do
     this before anything involving memory or registers.  */
  target_find_description ();

  if (!non_stop)
    {
      /* Use the previously fetched status.  */
      gdb_assert (wait_status != NULL);

      if (target_can_async_p ())
        {
          struct stop_reply *stop_reply;
          struct cleanup *old_chain;

          stop_reply = stop_reply_xmalloc ();
          old_chain = make_cleanup (do_stop_reply_xfree, stop_reply);
          remote_parse_stop_reply (wait_status, stop_reply);
          discard_cleanups (old_chain);
          push_stop_reply (stop_reply);

          target_async (inferior_event_handler, 0);
        }
      else
        {
          gdb_assert (wait_status != NULL);
          strcpy (rs->buf, wait_status);
          rs->cached_wait_status = 1;
        }
    }
  else
    gdb_assert (wait_status == NULL);
}

static void
extended_remote_attach (struct target_ops *ops, char *args, int from_tty)
{
  extended_remote_attach_1 (ops, args, from_tty);
}

/* Convert hex digit A to a number.  */

static int
fromhex (int a)
{
  if (a >= '0' && a <= '9')
    return a - '0';
  else if (a >= 'a' && a <= 'f')
    return a - 'a' + 10;
  else if (a >= 'A' && a <= 'F')
    return a - 'A' + 10;
  else
    error (_("Reply contains invalid hex digit %d"), a);
}

static int
hex2bin (const char *hex, gdb_byte *bin, int count)
{
  int i;

  for (i = 0; i < count; i++)
    {
      if (hex[0] == 0 || hex[1] == 0)
        {
          /* Hex string is short, or of uneven length.
             Return the count that has been converted so far.  */
          return i;
        }
      *bin++ = fromhex (hex[0]) * 16 + fromhex (hex[1]);
      hex += 2;
    }
  return i;
}

/* Convert number NIB to a hex digit.  */

static int
tohex (int nib)
{
  if (nib < 10)
    return '0' + nib;
  else
    return 'a' + nib - 10;
}

static int
bin2hex (const gdb_byte *bin, char *hex, int count)
{
  int i;
  /* May use a length, or a nul-terminated string as input.  */
  if (count == 0)
    count = strlen ((char *) bin);

  for (i = 0; i < count; i++)
    {
      *hex++ = tohex ((*bin >> 4) & 0xf);
      *hex++ = tohex (*bin++ & 0xf);
    }
  *hex = 0;
  return i;
}
\f
/* Check for the availability of vCont.  This function should also check
   the response.  */

static void
remote_vcont_probe (struct remote_state *rs)
{
  char *buf;

  strcpy (rs->buf, "vCont?");
  putpkt (rs->buf);
  getpkt (&rs->buf, &rs->buf_size, 0);
  buf = rs->buf;

  /* Make sure that the features we assume are supported.  */
  if (strncmp (buf, "vCont", 5) == 0)
    {
      char *p = &buf[5];
      int support_s, support_S, support_c, support_C;

      support_s = 0;
      support_S = 0;
      support_c = 0;
      support_C = 0;
      rs->support_vCont_t = 0;
      while (p && *p == ';')
        {
          p++;
          if (*p == 's' && (*(p + 1) == ';' || *(p + 1) == 0))
            support_s = 1;
          else if (*p == 'S' && (*(p + 1) == ';' || *(p + 1) == 0))
            support_S = 1;
          else if (*p == 'c' && (*(p + 1) == ';' || *(p + 1) == 0))
            support_c = 1;
          else if (*p == 'C' && (*(p + 1) == ';' || *(p + 1) == 0))
            support_C = 1;
          else if (*p == 't' && (*(p + 1) == ';' || *(p + 1) == 0))
            rs->support_vCont_t = 1;

          p = strchr (p, ';');
        }

      /* If s, S, c, and C are not all supported, we can't use vCont.  Clearing
         BUF will make packet_ok disable the packet.  */
      if (!support_s || !support_S || !support_c || !support_C)
        buf[0] = 0;
    }

  packet_ok (buf, &remote_protocol_packets[PACKET_vCont]);
}

/* Resume the remote inferior by using a "vCont" packet.  The thread
   to be resumed is PTID; STEP and SIGGNAL indicate whether the
   resumed thread should be single-stepped and/or signalled.  If PTID
   equals minus_one_ptid, then all threads are resumed; the thread to
   be stepped and/or signalled is given in the global INFERIOR_PTID.
   This function returns non-zero iff it resumes the inferior.

   This function issues a strict subset of all possible vCont commands at the
   moment.  */

static int
remote_vcont_resume (ptid_t ptid, int step, enum target_signal siggnal)
{
  struct remote_state *rs = get_remote_state ();
  char *p;
  char *endp;

  if (remote_protocol_packets[PACKET_vCont].support == PACKET_SUPPORT_UNKNOWN)
    remote_vcont_probe (rs);

  if (remote_protocol_packets[PACKET_vCont].support == PACKET_DISABLE)
    return 0;

  p = rs->buf;
  endp = rs->buf + get_remote_packet_size ();

  /* If we could generate a wider range of packets, we'd have to worry
     about overflowing BUF.  Should there be a generic
     "multi-part-packet" packet?  */

  if (ptid_equal (ptid, magic_null_ptid))
    {
      /* MAGIC_NULL_PTID means that we don't have any active threads,
         so we don't have any TID numbers the inferior will
         understand.  Make sure to only send forms that do not specify
         a TID.  */
      if (step && siggnal != TARGET_SIGNAL_0)
        xsnprintf (p, endp - p, "vCont;S%02x", siggnal);
      else if (step)
        xsnprintf (p, endp - p, "vCont;s");
      else if (siggnal != TARGET_SIGNAL_0)
        xsnprintf (p, endp - p, "vCont;C%02x", siggnal);
      else
        xsnprintf (p, endp - p, "vCont;c");
    }
  else if (ptid_equal (ptid, minus_one_ptid))
    {
      /* Resume all threads, with preference for INFERIOR_PTID.  */
      if (step && siggnal != TARGET_SIGNAL_0)
        {
          /* Step inferior_ptid with signal.  */
          p += xsnprintf (p, endp - p, "vCont;S%02x:", siggnal);
          p = write_ptid (p, endp, inferior_ptid);
          /* And continue others.  */
          p += xsnprintf (p, endp - p, ";c");
        }
      else if (step)
        {
          /* Step inferior_ptid.  */
          p += xsnprintf (p, endp - p, "vCont;s:");
          p = write_ptid (p, endp, inferior_ptid);
          /* And continue others.  */
          p += xsnprintf (p, endp - p, ";c");
        }
      else if (siggnal != TARGET_SIGNAL_0)
        {
          /* Continue inferior_ptid with signal.  */
          p += xsnprintf (p, endp - p, "vCont;C%02x:", siggnal);
          p = write_ptid (p, endp, inferior_ptid);
          /* And continue others.  */
          p += xsnprintf (p, endp - p, ";c");
        }
      else
        xsnprintf (p, endp - p, "vCont;c");
    }
  else
    {
      /* Scheduler locking; resume only PTID.  */
      if (step && siggnal != TARGET_SIGNAL_0)
        {
          /* Step ptid with signal.  */
          p += xsnprintf (p, endp - p, "vCont;S%02x:", siggnal);
          p = write_ptid (p, endp, ptid);
        }
      else if (step)
        {
          /* Step ptid.  */
          p += xsnprintf (p, endp - p, "vCont;s:");
          p = write_ptid (p, endp, ptid);
        }
      else if (siggnal != TARGET_SIGNAL_0)
        {
          /* Continue ptid with signal.  */
          p += xsnprintf (p, endp - p, "vCont;C%02x:", siggnal);
          p = write_ptid (p, endp, ptid);
        }
      else
        {
          /* Continue ptid.  */
          p += xsnprintf (p, endp - p, "vCont;c:");
          p = write_ptid (p, endp, ptid);
        }
    }

  gdb_assert (strlen (rs->buf) < get_remote_packet_size ());
  putpkt (rs->buf);

  if (non_stop)
    {
      /* In non-stop, the stub replies to vCont with "OK".  The stop
         reply will be reported asynchronously by means of a `%Stop'
         notification.  */
      getpkt (&rs->buf, &rs->buf_size, 0);
      if (strcmp (rs->buf, "OK") != 0)
        error (_("Unexpected vCont reply in non-stop mode: %s"), rs->buf);
    }

  return 1;
}

/* Tell the remote machine to resume.  */

static enum target_signal last_sent_signal = TARGET_SIGNAL_0;

static int last_sent_step;

static void
remote_resume (ptid_t ptid, int step, enum target_signal siggnal)
{
  struct remote_state *rs = get_remote_state ();
  char *buf;

  last_sent_signal = siggnal;
  last_sent_step = step;

  /* Update the inferior on signals to silently pass, if they've changed.  */
  remote_pass_signals ();

  /* The vCont packet doesn't need to specify threads via Hc.  */
  if (remote_vcont_resume (ptid, step, siggnal))
    goto done;

  /* All other supported resume packets do use Hc, so set the continue
     thread.  */
  if (ptid_equal (ptid, minus_one_ptid))
    set_continue_thread (any_thread_ptid);
  else
    set_continue_thread (ptid);

  buf = rs->buf;
  if (execution_direction == EXEC_REVERSE)
    {
      /* We don't pass signals to the target in reverse exec mode.  */
      if (info_verbose && siggnal != TARGET_SIGNAL_0)
        warning (" - Can't pass signal %d to target in reverse: ignored.\n",
                 siggnal);
      strcpy (buf, step ? "bs" : "bc");
    }
  else if (siggnal != TARGET_SIGNAL_0)
    {
      buf[0] = step ? 'S' : 'C';
      buf[1] = tohex (((int) siggnal >> 4) & 0xf);
      buf[2] = tohex (((int) siggnal) & 0xf);
      buf[3] = '\0';
    }
  else
    strcpy (buf, step ? "s" : "c");

  putpkt (buf);

 done:
  /* We are about to start executing the inferior, let's register it
     with the event loop. NOTE: this is the one place where all the
     execution commands end up. We could alternatively do this in each
     of the execution commands in infcmd.c.  */
  /* FIXME: ezannoni 1999-09-28: We may need to move this out of here
     into infcmd.c in order to allow inferior function calls to work
     NOT asynchronously.  */
  if (target_can_async_p ())
    target_async (inferior_event_handler, 0);

  /* We've just told the target to resume.  The remote server will
     wait for the inferior to stop, and then send a stop reply.  In
     the mean time, we can't start another command/query ourselves
     because the stub wouldn't be ready to process it.  This applies
     only to the base all-stop protocol, however.  In non-stop (which
     only supports vCont), the stub replies with an "OK", and is
     immediate able to process further serial input.  */
  if (!non_stop)
    rs->waiting_for_stop_reply = 1;
}
\f

/* Set up the signal handler for SIGINT, while the target is
   executing, ovewriting the 'regular' SIGINT signal handler.  */
static void
initialize_sigint_signal_handler (void)
{
  signal (SIGINT, handle_remote_sigint);
}

/* Signal handler for SIGINT, while the target is executing.  */
static void
handle_remote_sigint (int sig)
{
  signal (sig, handle_remote_sigint_twice);
  mark_async_signal_handler_wrapper (sigint_remote_token);
}

/* Signal handler for SIGINT, installed after SIGINT has already been
   sent once.  It will take effect the second time that the user sends
   a ^C.  */
static void
handle_remote_sigint_twice (int sig)
{
  signal (sig, handle_remote_sigint);
  mark_async_signal_handler_wrapper (sigint_remote_twice_token);
}

/* Perform the real interruption of the target execution, in response
   to a ^C.  */
static void
async_remote_interrupt (gdb_client_data arg)
{
  if (remote_debug)
    fprintf_unfiltered (gdb_stdlog, "remote_interrupt called\n");

  target_stop (inferior_ptid);
}

/* Perform interrupt, if the first attempt did not succeed. Just give
   up on the target alltogether.  */
void
async_remote_interrupt_twice (gdb_client_data arg)
{
  if (remote_debug)
    fprintf_unfiltered (gdb_stdlog, "remote_interrupt_twice called\n");

  interrupt_query ();
}

/* Reinstall the usual SIGINT handlers, after the target has
   stopped.  */
static void
cleanup_sigint_signal_handler (void *dummy)
{
  signal (SIGINT, handle_sigint);
}

/* Send ^C to target to halt it.  Target will respond, and send us a
   packet.  */
static void (*ofunc) (int);

/* The command line interface's stop routine. This function is installed
   as a signal handler for SIGINT. The first time a user requests a
   stop, we call remote_stop to send a break or ^C. If there is no
   response from the target (it didn't stop when the user requested it),
   we ask the user if he'd like to detach from the target.  */
static void
remote_interrupt (int signo)
{
  /* If this doesn't work, try more severe steps.  */
  signal (signo, remote_interrupt_twice);

  gdb_call_async_signal_handler (sigint_remote_token, 1);
}

/* The user typed ^C twice.  */

static void
remote_interrupt_twice (int signo)
{
  signal (signo, ofunc);
  gdb_call_async_signal_handler (sigint_remote_twice_token, 1);
  signal (signo, remote_interrupt);
}

/* Non-stop version of target_stop.  Uses `vCont;t' to stop a remote
   thread, all threads of a remote process, or all threads of all
   processes.  */

static void
remote_stop_ns (ptid_t ptid)
{
  struct remote_state *rs = get_remote_state ();
  char *p = rs->buf;
  char *endp = rs->buf + get_remote_packet_size ();
  struct stop_reply *reply, *next;

  if (remote_protocol_packets[PACKET_vCont].support == PACKET_SUPPORT_UNKNOWN)
    remote_vcont_probe (rs);

  if (!rs->support_vCont_t)
    error (_("Remote server does not support stopping threads"));

  if (ptid_equal (ptid, minus_one_ptid))
    p += xsnprintf (p, endp - p, "vCont;t");
  else
    {
      ptid_t nptid;

      /* Step inferior_ptid.  */
      p += xsnprintf (p, endp - p, "vCont;t:");

      if (ptid_is_pid (ptid))
          /* All (-1) threads of process.  */
        nptid = ptid_build (ptid_get_pid (ptid), 0, -1);
      else
        {
          /* Small optimization: if we already have a stop reply for
             this thread, no use in telling the stub we want this
             stopped.  */
          if (peek_stop_reply (ptid))
            return;

          nptid = ptid;
        }

      p = write_ptid (p, endp, nptid);
    }

  /* In non-stop, we get an immediate OK reply.  The stop reply will
     come in asynchronously by notification.  */
  putpkt (rs->buf);
  getpkt (&rs->buf, &rs->buf_size, 0);
  if (strcmp (rs->buf, "OK") != 0)
    error (_("Stopping %s failed: %s"), target_pid_to_str (ptid), rs->buf);
}

/* All-stop version of target_stop.  Sends a break or a ^C to stop the
   remote target.  It is undefined which thread of which process
   reports the stop.  */

static void
remote_stop_as (ptid_t ptid)
{
  struct remote_state *rs = get_remote_state ();

  /* If the inferior is stopped already, but the core didn't know
     about it yet, just ignore the request.  The cached wait status
     will be collected in remote_wait.  */
  if (rs->cached_wait_status)
    return;

  /* Send a break or a ^C, depending on user preference.  */

  if (remote_break)
    serial_send_break (remote_desc);
  else
    serial_write (remote_desc, "\003", 1);
}

/* This is the generic stop called via the target vector. When a target
   interrupt is requested, either by the command line or the GUI, we
   will eventually end up here.  */

static void
remote_stop (ptid_t ptid)
{
  if (remote_debug)
    fprintf_unfiltered (gdb_stdlog, "remote_stop called\n");

  if (non_stop)
    remote_stop_ns (ptid);
  else
    remote_stop_as (ptid);
}

/* Ask the user what to do when an interrupt is received.  */

static void
interrupt_query (void)
{
  target_terminal_ours ();

  if (target_can_async_p ())
    {
      signal (SIGINT, handle_sigint);
      deprecated_throw_reason (RETURN_QUIT);
    }
  else
    {
      if (query ("Interrupted while waiting for the program.\n\
Give up (and stop debugging it)? "))
        {
          pop_target ();
          deprecated_throw_reason (RETURN_QUIT);
        }
    }

  target_terminal_inferior ();
}

/* Enable/disable target terminal ownership.  Most targets can use
   terminal groups to control terminal ownership.  Remote targets are
   different in that explicit transfer of ownership to/from GDB/target
   is required.  */

static void
remote_terminal_inferior (void)
{
  if (!target_async_permitted)
    /* Nothing to do.  */
    return;

  /* FIXME: cagney/1999-09-27: Shouldn't need to test for
     sync_execution here.  This function should only be called when
     GDB is resuming the inferior in the forground.  A background
     resume (``run&'') should leave GDB in control of the terminal and
     consequently should not call this code.  */
  if (!sync_execution)
    return;
  /* FIXME: cagney/1999-09-27: Closely related to the above.  Make
     calls target_terminal_*() idenpotent. The event-loop GDB talking
     to an asynchronous target with a synchronous command calls this
     function from both event-top.c and infrun.c/infcmd.c.  Once GDB
     stops trying to transfer the terminal to the target when it
     shouldn't this guard can go away.  */
  if (!remote_async_terminal_ours_p)
    return;
  delete_file_handler (input_fd);
  remote_async_terminal_ours_p = 0;
  initialize_sigint_signal_handler ();
  /* NOTE: At this point we could also register our selves as the
     recipient of all input.  Any characters typed could then be
     passed on down to the target.  */
}

static void
remote_terminal_ours (void)
{
  if (!target_async_permitted)
    /* Nothing to do.  */
    return;

  /* See FIXME in remote_terminal_inferior.  */
  if (!sync_execution)
    return;
  /* See FIXME in remote_terminal_inferior.  */
  if (remote_async_terminal_ours_p)
    return;
  cleanup_sigint_signal_handler (NULL);
  add_file_handler (input_fd, stdin_event_handler, 0);
  remote_async_terminal_ours_p = 1;
}

void
remote_console_output (char *msg)
{
  char *p;

  for (p = msg; p[0] && p[1]; p += 2)
    {
      char tb[2];
      char c = fromhex (p[0]) * 16 + fromhex (p[1]);
      tb[0] = c;
      tb[1] = 0;
      fputs_unfiltered (tb, gdb_stdtarg);
    }
    gdb_flush (gdb_stdtarg);
  }

typedef struct cached_reg
{
  int num;
  gdb_byte data[MAX_REGISTER_SIZE];
} cached_reg_t;

DEF_VEC_O(cached_reg_t);

struct stop_reply
{
  struct stop_reply *next;

  ptid_t ptid;

  struct target_waitstatus ws;

  VEC(cached_reg_t) *regcache;

  int stopped_by_watchpoint_p;
  CORE_ADDR watch_data_address;

  int solibs_changed;
  int replay_event;
};

/* The list of already fetched and acknowledged stop events.  */
static struct stop_reply *stop_reply_queue;

static struct stop_reply *
stop_reply_xmalloc (void)
{
  struct stop_reply *r = XMALLOC (struct stop_reply);
  r->next = NULL;
  return r;
}

static void
stop_reply_xfree (struct stop_reply *r)
{
  if (r != NULL)
    {
      VEC_free (cached_reg_t, r->regcache);
      xfree (r);
    }
}

/* Discard all pending stop replies of inferior PID.  If PID is -1,
   discard everything.  */

static void
discard_pending_stop_replies (int pid)
{
  struct stop_reply *prev = NULL, *reply, *next;

  /* Discard the in-flight notification.  */
  if (pending_stop_reply != NULL
      && (pid == -1
          || ptid_get_pid (pending_stop_reply->ptid) == pid))
    {
      stop_reply_xfree (pending_stop_reply);
      pending_stop_reply = NULL;
    }

  /* Discard the stop replies we have already pulled with
     vStopped.  */
  for (reply = stop_reply_queue; reply; reply = next)
    {
      next = reply->next;
      if (pid == -1
          || ptid_get_pid (reply->ptid) == pid)
        {
          if (reply == stop_reply_queue)
            stop_reply_queue = reply->next;
          else
            prev->next = reply->next;

          stop_reply_xfree (reply);
        }
      else
        prev = reply;
    }
}

/* Cleanup wrapper.  */

static void
do_stop_reply_xfree (void *arg)
{
  struct stop_reply *r = arg;
  stop_reply_xfree (r);
}

/* Look for a queued stop reply belonging to PTID.  If one is found,
   remove it from the queue, and return it.  Returns NULL if none is
   found.  If there are still queued events left to process, tell the
   event loop to get back to target_wait soon.  */

static struct stop_reply *
queued_stop_reply (ptid_t ptid)
{
  struct stop_reply *it, *prev;
  struct stop_reply head;

  head.next = stop_reply_queue;
  prev = &head;

  it = head.next;

  if (!ptid_equal (ptid, minus_one_ptid))
    for (; it; prev = it, it = it->next)
      if (ptid_equal (ptid, it->ptid))
        break;

  if (it)
    {
      prev->next = it->next;
      it->next = NULL;
    }

  stop_reply_queue = head.next;

  if (stop_reply_queue)
    /* There's still at least an event left.  */
    mark_async_event_handler (remote_async_inferior_event_token);

  return it;
}

/* Push a fully parsed stop reply in the stop reply queue.  Since we
   know that we now have at least one queued event left to pass to the
   core side, tell the event loop to get back to target_wait soon.  */

static void
push_stop_reply (struct stop_reply *new_event)
{
  struct stop_reply *event;

  if (stop_reply_queue)
    {
      for (event = stop_reply_queue;
           event && event->next;
           event = event->next)
        ;

      event->next = new_event;
    }
  else
    stop_reply_queue = new_event;

  mark_async_event_handler (remote_async_inferior_event_token);
}

/* Returns true if we have a stop reply for PTID.  */

static int
peek_stop_reply (ptid_t ptid)
{
  struct stop_reply *it;

  for (it = stop_reply_queue; it; it = it->next)
    if (ptid_equal (ptid, it->ptid))
      {
        if (it->ws.kind == TARGET_WAITKIND_STOPPED)
          return 1;
      }

  return 0;
}

/* Parse the stop reply in BUF.  Either the function succeeds, and the
   result is stored in EVENT, or throws an error.  */

static void
remote_parse_stop_reply (char *buf, struct stop_reply *event)
{
  struct remote_arch_state *rsa = get_remote_arch_state ();
  ULONGEST addr;
  char *p;

  event->ptid = null_ptid;
  event->ws.kind = TARGET_WAITKIND_IGNORE;
  event->ws.value.integer = 0;
  event->solibs_changed = 0;
  event->replay_event = 0;
  event->stopped_by_watchpoint_p = 0;
  event->regcache = NULL;

  switch (buf[0])
    {
    case 'T':           /* Status with PC, SP, FP, ...  */
      {
        gdb_byte regs[MAX_REGISTER_SIZE];

        /* Expedited reply, containing Signal, {regno, reg} repeat.  */
        /*  format is:  'Tssn...:r...;n...:r...;n...:r...;#cc', where
           ss = signal number
           n... = register number
           r... = register contents
        */

        p = &buf[3];    /* after Txx */
        while (*p)
          {
            char *p1;
            char *p_temp;
            int fieldsize;
            LONGEST pnum = 0;

            /* If the packet contains a register number, save it in
               pnum and set p1 to point to the character following it.
               Otherwise p1 points to p.  */

            /* If this packet is an awatch packet, don't parse the 'a'
               as a register number.  */

            if (strncmp (p, "awatch", strlen("awatch")) != 0)
              {
                /* Read the ``P'' register number.  */
                pnum = strtol (p, &p_temp, 16);
                p1 = p_temp;
              }
            else
              p1 = p;

            if (p1 == p)        /* No register number present here.  */
              {
                p1 = strchr (p, ':');
                if (p1 == NULL)
                  error (_("Malformed packet(a) (missing colon): %s\n\
Packet: '%s'\n"),
                         p, buf);
                if (strncmp (p, "thread", p1 - p) == 0)
                  event->ptid = read_ptid (++p1, &p);
                else if ((strncmp (p, "watch", p1 - p) == 0)
                         || (strncmp (p, "rwatch", p1 - p) == 0)
                         || (strncmp (p, "awatch", p1 - p) == 0))
                  {
                    event->stopped_by_watchpoint_p = 1;
                    p = unpack_varlen_hex (++p1, &addr);
                    event->watch_data_address = (CORE_ADDR) addr;
                  }
                else if (strncmp (p, "library", p1 - p) == 0)
                  {
                    p1++;
                    p_temp = p1;
                    while (*p_temp && *p_temp != ';')
                      p_temp++;

                    event->solibs_changed = 1;
                    p = p_temp;
                  }
                else if (strncmp (p, "replaylog", p1 - p) == 0)
                  {
                    /* NO_HISTORY event.
                       p1 will indicate "begin" or "end", but
                       it makes no difference for now, so ignore it.  */
                    event->replay_event = 1;
                    p_temp = strchr (p1 + 1, ';');
                    if (p_temp)
                      p = p_temp;
                  }
                else
                  {
                    /* Silently skip unknown optional info.  */
                    p_temp = strchr (p1 + 1, ';');
                    if (p_temp)
                      p = p_temp;
                  }
              }
            else
              {
                struct packet_reg *reg = packet_reg_from_pnum (rsa, pnum);
                cached_reg_t cached_reg;

                cached_reg.num = reg->regnum;

                p = p1;

                if (*p != ':')
                  error (_("Malformed packet(b) (missing colon): %s\n\
Packet: '%s'\n"),
                         p, buf);
                ++p;

                if (reg == NULL)
                  error (_("Remote sent bad register number %s: %s\n\
Packet: '%s'\n"),
                         phex_nz (pnum, 0), p, buf);

                fieldsize = hex2bin (p, cached_reg.data,
                                     register_size (target_gdbarch,
                                                    reg->regnum));
                p += 2 * fieldsize;
                if (fieldsize < register_size (target_gdbarch,
                                               reg->regnum))
                  warning (_("Remote reply is too short: %s"), buf);

                VEC_safe_push (cached_reg_t, event->regcache, &cached_reg);
              }

            if (*p != ';')
              error (_("Remote register badly formatted: %s\nhere: %s"),
                     buf, p);
            ++p;
          }
      }
      /* fall through */
    case 'S':           /* Old style status, just signal only.  */
      if (event->solibs_changed)
        event->ws.kind = TARGET_WAITKIND_LOADED;
      else if (event->replay_event)
        event->ws.kind = TARGET_WAITKIND_NO_HISTORY;
      else
        {
          event->ws.kind = TARGET_WAITKIND_STOPPED;
          event->ws.value.sig = (enum target_signal)
            (((fromhex (buf[1])) << 4) + (fromhex (buf[2])));
        }
      break;
    case 'W':           /* Target exited.  */
    case 'X':
      {
        char *p;
        int pid;
        ULONGEST value;

        /* GDB used to accept only 2 hex chars here.  Stubs should
           only send more if they detect GDB supports multi-process
           support.  */
        p = unpack_varlen_hex (&buf[1], &value);

        if (buf[0] == 'W')
          {
            /* The remote process exited.  */
            event->ws.kind = TARGET_WAITKIND_EXITED;
            event->ws.value.integer = value;
          }
        else
          {
            /* The remote process exited with a signal.  */
            event->ws.kind = TARGET_WAITKIND_SIGNALLED;
            event->ws.value.sig = (enum target_signal) value;
          }

        /* If no process is specified, assume inferior_ptid.  */
        pid = ptid_get_pid (inferior_ptid);
        if (*p == '\0')
          ;
        else if (*p == ';')
          {
            p++;

            if (p == '\0')
              ;
            else if (strncmp (p,
                              "process:", sizeof ("process:") - 1) == 0)
              {
                ULONGEST upid;
                p += sizeof ("process:") - 1;
                unpack_varlen_hex (p, &upid);
                pid = upid;
              }
            else
              error (_("unknown stop reply packet: %s"), buf);
          }
        else
          error (_("unknown stop reply packet: %s"), buf);
        event->ptid = pid_to_ptid (pid);
      }
      break;
    }

  if (non_stop && ptid_equal (event->ptid, null_ptid))
    error (_("No process or thread specified in stop reply: %s"), buf);
}

/* When the stub wants to tell GDB about a new stop reply, it sends a
   stop notification (%Stop).  Those can come it at any time, hence,
   we have to make sure that any pending putpkt/getpkt sequence we're
   making is finished, before querying the stub for more events with
   vStopped.  E.g., if we started a vStopped sequence immediatelly
   upon receiving the %Stop notification, something like this could
   happen:

    1.1) --> Hg 1
    1.2) <-- OK
    1.3) --> g
    1.4) <-- %Stop
    1.5) --> vStopped
    1.6) <-- (registers reply to step #1.3)

   Obviously, the reply in step #1.6 would be unexpected to a vStopped
   query.

   To solve this, whenever we parse a %Stop notification sucessfully,
   we mark the REMOTE_ASYNC_GET_PENDING_EVENTS_TOKEN, and carry on
   doing whatever we were doing:

    2.1) --> Hg 1
    2.2) <-- OK
    2.3) --> g
    2.4) <-- %Stop
      <GDB marks the REMOTE_ASYNC_GET_PENDING_EVENTS_TOKEN>
    2.5) <-- (registers reply to step #2.3)

   Eventualy after step #2.5, we return to the event loop, which
   notices there's an event on the
   REMOTE_ASYNC_GET_PENDING_EVENTS_TOKEN event and calls the
   associated callback --- the function below.  At this point, we're
   always safe to start a vStopped sequence. :

    2.6) --> vStopped
    2.7) <-- T05 thread:2
    2.8) --> vStopped
    2.9) --> OK
*/

static void
remote_get_pending_stop_replies (void)
{
  struct remote_state *rs = get_remote_state ();
  int ret;

  if (pending_stop_reply)
    {
      /* acknowledge */
      putpkt ("vStopped");

      /* Now we can rely on it.  */
      push_stop_reply (pending_stop_reply);
      pending_stop_reply = NULL;

      while (1)
        {
          getpkt (&rs->buf, &rs->buf_size, 0);
          if (strcmp (rs->buf, "OK") == 0)
            break;
          else
            {
              struct cleanup *old_chain;
              struct stop_reply *stop_reply = stop_reply_xmalloc ();

              old_chain = make_cleanup (do_stop_reply_xfree, stop_reply);
              remote_parse_stop_reply (rs->buf, stop_reply);

              /* acknowledge */
              putpkt ("vStopped");

              if (stop_reply->ws.kind != TARGET_WAITKIND_IGNORE)
                {
                  /* Now we can rely on it.  */
                  discard_cleanups (old_chain);
                  push_stop_reply (stop_reply);
                }
              else
                /* We got an unknown stop reply.  */
                do_cleanups (old_chain);
            }
        }
    }
}


/* Called when it is decided that STOP_REPLY holds the info of the
   event that is to be returned to the core.  This function always
   destroys STOP_REPLY.  */

static ptid_t
process_stop_reply (struct stop_reply *stop_reply,
                    struct target_waitstatus *status)
{
  ptid_t ptid;

  *status = stop_reply->ws;
  ptid = stop_reply->ptid;

  /* If no thread/process was reported by the stub, assume the current
     inferior.  */
  if (ptid_equal (ptid, null_ptid))
    ptid = inferior_ptid;

  if (status->kind == TARGET_WAITKIND_EXITED
      || status->kind == TARGET_WAITKIND_SIGNALLED)
    {
      int pid = ptid_get_pid (ptid);
      delete_inferior (pid);
    }
  else
    notice_new_inferiors (ptid);

  /* Expedited registers.  */
  if (stop_reply->regcache)
    {
      cached_reg_t *reg;
      int ix;

      for (ix = 0;
           VEC_iterate(cached_reg_t, stop_reply->regcache, ix, reg);
           ix++)
        regcache_raw_supply (get_thread_regcache (ptid),
                             reg->num, reg->data);
      VEC_free (cached_reg_t, stop_reply->regcache);
    }

  remote_stopped_by_watchpoint_p = stop_reply->stopped_by_watchpoint_p;
  remote_watch_data_address = stop_reply->watch_data_address;

  stop_reply_xfree (stop_reply);
  return ptid;
}

/* The non-stop mode version of target_wait.  */

static ptid_t
remote_wait_ns (ptid_t ptid, struct target_waitstatus *status)
{
  struct remote_state *rs = get_remote_state ();
  struct remote_arch_state *rsa = get_remote_arch_state ();
  ptid_t event_ptid = null_ptid;
  struct stop_reply *stop_reply;
  int ret;

  /* If in non-stop mode, get out of getpkt even if a
     notification is received.  */

  ret = getpkt_or_notif_sane (&rs->buf, &rs->buf_size,
                              0 /* forever */);
  while (1)
    {
      if (ret != -1)
        switch (rs->buf[0])
          {
          case 'E':             /* Error of some sort.  */
            /* We're out of sync with the target now.  Did it continue
               or not?  We can't tell which thread it was in non-stop,
               so just ignore this.  */
            warning (_("Remote failure reply: %s"), rs->buf);
            break;
          case 'O':             /* Console output.  */
            remote_console_output (rs->buf + 1);
            break;
          default:
            warning (_("Invalid remote reply: %s"), rs->buf);
            break;
          }

      /* Acknowledge a pending stop reply that may have arrived in the
         mean time.  */
      if (pending_stop_reply != NULL)
        remote_get_pending_stop_replies ();

      /* If indeed we noticed a stop reply, we're done.  */
      stop_reply = queued_stop_reply (ptid);
      if (stop_reply != NULL)
        return process_stop_reply (stop_reply, status);

      /* Still no event.  If we're in asynchronous mode, then just
         return to the event loop.  */
      if (remote_is_async_p ())
        {
          status->kind = TARGET_WAITKIND_IGNORE;
          return minus_one_ptid;
        }

      /* Otherwise, asynchronous mode is masked, so do a blocking
         wait.  */
      ret = getpkt_or_notif_sane (&rs->buf, &rs->buf_size,
                                  1 /* forever */);
    }
}

/* Wait until the remote machine stops, then return, storing status in
   STATUS just as `wait' would.  */

static ptid_t
remote_wait_as (ptid_t ptid, struct target_waitstatus *status)
{
  struct remote_state *rs = get_remote_state ();
  struct remote_arch_state *rsa = get_remote_arch_state ();
  ptid_t event_ptid = null_ptid;
  ULONGEST addr;
  int solibs_changed = 0;
  char *buf, *p;
  struct stop_reply *stop_reply;

  status->kind = TARGET_WAITKIND_IGNORE;
  status->value.integer = 0;

  stop_reply = queued_stop_reply (ptid);
  if (stop_reply != NULL)
    return process_stop_reply (stop_reply, status);

  if (rs->cached_wait_status)
    /* Use the cached wait status, but only once.  */
    rs->cached_wait_status = 0;
  else
    {
      int ret;

      if (!target_is_async_p ())
        {
          ofunc = signal (SIGINT, remote_interrupt);
          /* If the user hit C-c before this packet, or between packets,
             pretend that it was hit right here.  */
          if (quit_flag)
            {
              quit_flag = 0;
              remote_interrupt (SIGINT);
            }
        }

      /* FIXME: cagney/1999-09-27: If we're in async mode we should
         _never_ wait for ever -> test on target_is_async_p().
         However, before we do that we need to ensure that the caller
         knows how to take the target into/out of async mode.  */
      ret = getpkt_sane (&rs->buf, &rs->buf_size, wait_forever_enabled_p);
      if (!target_is_async_p ())
        signal (SIGINT, ofunc);
    }

  buf = rs->buf;

  remote_stopped_by_watchpoint_p = 0;

  /* We got something.  */
  rs->waiting_for_stop_reply = 0;

  switch (buf[0])
    {
    case 'E':           /* Error of some sort.  */
      /* We're out of sync with the target now.  Did it continue or
         not?  Not is more likely, so report a stop.  */
      warning (_("Remote failure reply: %s"), buf);
      status->kind = TARGET_WAITKIND_STOPPED;
      status->value.sig = TARGET_SIGNAL_0;
      break;
    case 'F':           /* File-I/O request.  */
      remote_fileio_request (buf);
      break;
    case 'T': case 'S': case 'X': case 'W':
      {
        struct stop_reply *stop_reply;
        struct cleanup *old_chain;

        stop_reply = stop_reply_xmalloc ();
        old_chain = make_cleanup (do_stop_reply_xfree, stop_reply);
        remote_parse_stop_reply (buf, stop_reply);
        discard_cleanups (old_chain);
        event_ptid = process_stop_reply (stop_reply, status);
        break;
      }
    case 'O':           /* Console output.  */
      remote_console_output (buf + 1);

      /* The target didn't really stop; keep waiting.  */
      rs->waiting_for_stop_reply = 1;

      break;
    case '\0':
      if (last_sent_signal != TARGET_SIGNAL_0)
        {
          /* Zero length reply means that we tried 'S' or 'C' and the
             remote system doesn't support it.  */
          target_terminal_ours_for_output ();
          printf_filtered
            ("Can't send signals to this remote system.  %s not sent.\n",
             target_signal_to_name (last_sent_signal));
          last_sent_signal = TARGET_SIGNAL_0;
          target_terminal_inferior ();

          strcpy ((char *) buf, last_sent_step ? "s" : "c");
          putpkt ((char *) buf);

          /* We just told the target to resume, so a stop reply is in
             order.  */
          rs->waiting_for_stop_reply = 1;
          break;
        }
      /* else fallthrough */
    default:
      warning (_("Invalid remote reply: %s"), buf);
      /* Keep waiting.  */
      rs->waiting_for_stop_reply = 1;
      break;
    }

  if (status->kind == TARGET_WAITKIND_IGNORE)
    /* Nothing interesting happened.  */
    return minus_one_ptid;
  else if (status->kind != TARGET_WAITKIND_EXITED
           && status->kind != TARGET_WAITKIND_SIGNALLED)
    {
      if (!ptid_equal (event_ptid, null_ptid))
        record_currthread (event_ptid);
      else
        event_ptid = inferior_ptid;
    }
  else
    /* A process exit.  Invalidate our notion of current thread.  */
    record_currthread (minus_one_ptid);

  return event_ptid;
}

/* Wait until the remote machine stops, then return, storing status in
   STATUS just as `wait' would.  */

static ptid_t
remote_wait (ptid_t ptid, struct target_waitstatus *status)
{
  ptid_t event_ptid;

  if (non_stop)
    event_ptid = remote_wait_ns (ptid, status);
  else
    {
      /* In synchronous mode, keep waiting until the target stops.  In
         asynchronous mode, always return to the event loop.  */

      do
        {
          event_ptid = remote_wait_as (ptid, status);
        }
      while (status->kind == TARGET_WAITKIND_IGNORE
             && !target_can_async_p ());
    }

  if (target_can_async_p ())
    {
      /* If there are are events left in the queue tell the event loop
         to return here.  */
      if (stop_reply_queue)
        mark_async_event_handler (remote_async_inferior_event_token);
    }

  return event_ptid;
}

/* Fetch a single register using a 'p' packet.  */

static int
fetch_register_using_p (struct regcache *regcache, struct packet_reg *reg)
{
  struct remote_state *rs = get_remote_state ();
  char *buf, *p;
  char regp[MAX_REGISTER_SIZE];
  int i;

  if (remote_protocol_packets[PACKET_p].support == PACKET_DISABLE)
    return 0;

  if (reg->pnum == -1)
    return 0;

  p = rs->buf;
  *p++ = 'p';
  p += hexnumstr (p, reg->pnum);
  *p++ = '\0';
  remote_send (&rs->buf, &rs->buf_size);

  buf = rs->buf;

  switch (packet_ok (buf, &remote_protocol_packets[PACKET_p]))
    {
    case PACKET_OK:
      break;
    case PACKET_UNKNOWN:
      return 0;
    case PACKET_ERROR:
      error (_("Could not fetch register \"%s\""),
             gdbarch_register_name (get_regcache_arch (regcache), reg->regnum));
    }

  /* If this register is unfetchable, tell the regcache.  */
  if (buf[0] == 'x')
    {
      regcache_raw_supply (regcache, reg->regnum, NULL);
      return 1;
    }

  /* Otherwise, parse and supply the value.  */
  p = buf;
  i = 0;
  while (p[0] != 0)
    {
      if (p[1] == 0)
        error (_("fetch_register_using_p: early buf termination"));

      regp[i++] = fromhex (p[0]) * 16 + fromhex (p[1]);
      p += 2;
    }
  regcache_raw_supply (regcache, reg->regnum, regp);
  return 1;
}

/* Fetch the registers included in the target's 'g' packet.  */

static int
send_g_packet (void)
{
  struct remote_state *rs = get_remote_state ();
  int i, buf_len;
  char *p;
  char *regs;

  sprintf (rs->buf, "g");
  remote_send (&rs->buf, &rs->buf_size);

  /* We can get out of synch in various cases.  If the first character
     in the buffer is not a hex character, assume that has happened
     and try to fetch another packet to read.  */
  while ((rs->buf[0] < '0' || rs->buf[0] > '9')
         && (rs->buf[0] < 'A' || rs->buf[0] > 'F')
         && (rs->buf[0] < 'a' || rs->buf[0] > 'f')
         && rs->buf[0] != 'x')  /* New: unavailable register value.  */
    {
      if (remote_debug)
        fprintf_unfiltered (gdb_stdlog,
                            "Bad register packet; fetching a new packet\n");
      getpkt (&rs->buf, &rs->buf_size, 0);
    }

  buf_len = strlen (rs->buf);

  /* Sanity check the received packet.  */
  if (buf_len % 2 != 0)
    error (_("Remote 'g' packet reply is of odd length: %s"), rs->buf);

  return buf_len / 2;
}

static void
process_g_packet (struct regcache *regcache)
{
  struct gdbarch *gdbarch = get_regcache_arch (regcache);
  struct remote_state *rs = get_remote_state ();
  struct remote_arch_state *rsa = get_remote_arch_state ();
  int i, buf_len;
  char *p;
  char *regs;

  buf_len = strlen (rs->buf);

  /* Further sanity checks, with knowledge of the architecture.  */
  if (buf_len > 2 * rsa->sizeof_g_packet)
    error (_("Remote 'g' packet reply is too long: %s"), rs->buf);

  /* Save the size of the packet sent to us by the target.  It is used
     as a heuristic when determining the max size of packets that the
     target can safely receive.  */
  if (rsa->actual_register_packet_size == 0)
    rsa->actual_register_packet_size = buf_len;

  /* If this is smaller than we guessed the 'g' packet would be,
     update our records.  A 'g' reply that doesn't include a register's
     value implies either that the register is not available, or that
     the 'p' packet must be used.  */
  if (buf_len < 2 * rsa->sizeof_g_packet)
    {
      rsa->sizeof_g_packet = buf_len / 2;

      for (i = 0; i < gdbarch_num_regs (gdbarch); i++)
        {
          if (rsa->regs[i].pnum == -1)
            continue;

          if (rsa->regs[i].offset >= rsa->sizeof_g_packet)
            rsa->regs[i].in_g_packet = 0;
          else
            rsa->regs[i].in_g_packet = 1;
        }
    }

  regs = alloca (rsa->sizeof_g_packet);

  /* Unimplemented registers read as all bits zero.  */
  memset (regs, 0, rsa->sizeof_g_packet);

  /* Reply describes registers byte by byte, each byte encoded as two
     hex characters.  Suck them all up, then supply them to the
     register cacheing/storage mechanism.  */

  p = rs->buf;
  for (i = 0; i < rsa->sizeof_g_packet; i++)
    {
      if (p[0] == 0 || p[1] == 0)
        /* This shouldn't happen - we adjusted sizeof_g_packet above.  */
        internal_error (__FILE__, __LINE__,
                        "unexpected end of 'g' packet reply");

      if (p[0] == 'x' && p[1] == 'x')
        regs[i] = 0;            /* 'x' */
      else
        regs[i] = fromhex (p[0]) * 16 + fromhex (p[1]);
      p += 2;
    }

  {
    int i;
    for (i = 0; i < gdbarch_num_regs (gdbarch); i++)
      {
        struct packet_reg *r = &rsa->regs[i];
        if (r->in_g_packet)
          {
            if (r->offset * 2 >= strlen (rs->buf))
              /* This shouldn't happen - we adjusted in_g_packet above.  */
              internal_error (__FILE__, __LINE__,
                              "unexpected end of 'g' packet reply");
            else if (rs->buf[r->offset * 2] == 'x')
              {
                gdb_assert (r->offset * 2 < strlen (rs->buf));
                /* The register isn't available, mark it as such (at
                   the same time setting the value to zero).  */
                regcache_raw_supply (regcache, r->regnum, NULL);
              }
            else
              regcache_raw_supply (regcache, r->regnum,
                                   regs + r->offset);
          }
      }
  }
}

static void
fetch_registers_using_g (struct regcache *regcache)
{
  send_g_packet ();
  process_g_packet (regcache);
}

static void
remote_fetch_registers (struct regcache *regcache, int regnum)
{
  struct remote_state *rs = get_remote_state ();
  struct remote_arch_state *rsa = get_remote_arch_state ();
  int i;

  set_general_thread (inferior_ptid);

  if (regnum >= 0)
    {
      struct packet_reg *reg = packet_reg_from_regnum (rsa, regnum);
      gdb_assert (reg != NULL);

      /* If this register might be in the 'g' packet, try that first -
         we are likely to read more than one register.  If this is the
         first 'g' packet, we might be overly optimistic about its
         contents, so fall back to 'p'.  */
      if (reg->in_g_packet)
        {
          fetch_registers_using_g (regcache);
          if (reg->in_g_packet)
            return;
        }

      if (fetch_register_using_p (regcache, reg))
        return;

      /* This register is not available.  */
      regcache_raw_supply (regcache, reg->regnum, NULL);

      return;
    }

  fetch_registers_using_g (regcache);

  for (i = 0; i < gdbarch_num_regs (get_regcache_arch (regcache)); i++)
    if (!rsa->regs[i].in_g_packet)
      if (!fetch_register_using_p (regcache, &rsa->regs[i]))
        {
          /* This register is not available.  */
          regcache_raw_supply (regcache, i, NULL);
        }
}

/* Prepare to store registers.  Since we may send them all (using a
   'G' request), we have to read out the ones we don't want to change
   first.  */

static void
remote_prepare_to_store (struct regcache *regcache)
{
  struct remote_arch_state *rsa = get_remote_arch_state ();
  int i;
  gdb_byte buf[MAX_REGISTER_SIZE];

  /* Make sure the entire registers array is valid.  */
  switch (remote_protocol_packets[PACKET_P].support)
    {
    case PACKET_DISABLE:
    case PACKET_SUPPORT_UNKNOWN:
      /* Make sure all the necessary registers are cached.  */
      for (i = 0; i < gdbarch_num_regs (get_regcache_arch (regcache)); i++)
        if (rsa->regs[i].in_g_packet)
          regcache_raw_read (regcache, rsa->regs[i].regnum, buf);
      break;
    case PACKET_ENABLE:
      break;
    }
}

/* Helper: Attempt to store REGNUM using the P packet.  Return fail IFF
   packet was not recognized.  */

static int
store_register_using_P (const struct regcache *regcache, struct packet_reg *reg)
{
  struct gdbarch *gdbarch = get_regcache_arch (regcache);
  struct remote_state *rs = get_remote_state ();
  struct remote_arch_state *rsa = get_remote_arch_state ();
  /* Try storing a single register.  */
  char *buf = rs->buf;
  gdb_byte regp[MAX_REGISTER_SIZE];
  char *p;

  if (remote_protocol_packets[PACKET_P].support == PACKET_DISABLE)
    return 0;

  if (reg->pnum == -1)
    return 0;

  xsnprintf (buf, get_remote_packet_size (), "P%s=", phex_nz (reg->pnum, 0));
  p = buf + strlen (buf);
  regcache_raw_collect (regcache, reg->regnum, regp);
  bin2hex (regp, p, register_size (gdbarch, reg->regnum));
  remote_send (&rs->buf, &rs->buf_size);

  switch (packet_ok (rs->buf, &remote_protocol_packets[PACKET_P]))
    {
    case PACKET_OK:
      return 1;
    case PACKET_ERROR:
      error (_("Could not write register \"%s\""),
             gdbarch_register_name (gdbarch, reg->regnum));
    case PACKET_UNKNOWN:
      return 0;
    default:
      internal_error (__FILE__, __LINE__, _("Bad result from packet_ok"));
    }
}

/* Store register REGNUM, or all registers if REGNUM == -1, from the
   contents of the register cache buffer.  FIXME: ignores errors.  */

static void
store_registers_using_G (const struct regcache *regcache)
{
  struct remote_state *rs = get_remote_state ();
  struct remote_arch_state *rsa = get_remote_arch_state ();
  gdb_byte *regs;
  char *p;

  /* Extract all the registers in the regcache copying them into a
     local buffer.  */
  {
    int i;
    regs = alloca (rsa->sizeof_g_packet);
    memset (regs, 0, rsa->sizeof_g_packet);
    for (i = 0; i < gdbarch_num_regs (get_regcache_arch (regcache)); i++)
      {
        struct packet_reg *r = &rsa->regs[i];
        if (r->in_g_packet)
          regcache_raw_collect (regcache, r->regnum, regs + r->offset);
      }
  }

  /* Command describes registers byte by byte,
     each byte encoded as two hex characters.  */
  p = rs->buf;
  *p++ = 'G';
  /* remote_prepare_to_store insures that rsa->sizeof_g_packet gets
     updated.  */
  bin2hex (regs, p, rsa->sizeof_g_packet);
  remote_send (&rs->buf, &rs->buf_size);
}

/* Store register REGNUM, or all registers if REGNUM == -1, from the contents
   of the register cache buffer.  FIXME: ignores errors.  */

static void
remote_store_registers (struct regcache *regcache, int regnum)
{
  struct remote_state *rs = get_remote_state ();
  struct remote_arch_state *rsa = get_remote_arch_state ();
  int i;

  set_general_thread (inferior_ptid);

  if (regnum >= 0)
    {
      struct packet_reg *reg = packet_reg_from_regnum (rsa, regnum);
      gdb_assert (reg != NULL);

      /* Always prefer to store registers using the 'P' packet if
         possible; we often change only a small number of registers.
         Sometimes we change a larger number; we'd need help from a
         higher layer to know to use 'G'.  */
      if (store_register_using_P (regcache, reg))
        return;

      /* For now, don't complain if we have no way to write the
         register.  GDB loses track of unavailable registers too
         easily.  Some day, this may be an error.  We don't have
         any way to read the register, either... */
      if (!reg->in_g_packet)
        return;

      store_registers_using_G (regcache);
      return;
    }

  store_registers_using_G (regcache);

  for (i = 0; i < gdbarch_num_regs (get_regcache_arch (regcache)); i++)
    if (!rsa->regs[i].in_g_packet)
      if (!store_register_using_P (regcache, &rsa->regs[i]))
        /* See above for why we do not issue an error here.  */
        continue;
}
\f

/* Return the number of hex digits in num.  */

static int
hexnumlen (ULONGEST num)
{
  int i;

  for (i = 0; num != 0; i++)
    num >>= 4;

  return max (i, 1);
}

/* Set BUF to the minimum number of hex digits representing NUM.  */

static int
hexnumstr (char *buf, ULONGEST num)
{
  int len = hexnumlen (num);
  return hexnumnstr (buf, num, len);
}


/* Set BUF to the hex digits representing NUM, padded to WIDTH characters.  */

static int
hexnumnstr (char *buf, ULONGEST num, int width)
{
  int i;

  buf[width] = '\0';

  for (i = width - 1; i >= 0; i--)
    {
      buf[i] = "0123456789abcdef"[(num & 0xf)];
      num >>= 4;
    }

  return width;
}

/* Mask all but the least significant REMOTE_ADDRESS_SIZE bits.  */

static CORE_ADDR
remote_address_masked (CORE_ADDR addr)
{
  int address_size = remote_address_size;
  /* If "remoteaddresssize" was not set, default to target address size.  */
  if (!address_size)
    address_size = gdbarch_addr_bit (target_gdbarch);

  if (address_size > 0
      && address_size < (sizeof (ULONGEST) * 8))
    {
      /* Only create a mask when that mask can safely be constructed
         in a ULONGEST variable.  */
      ULONGEST mask = 1;
      mask = (mask << address_size) - 1;
      addr &= mask;
    }
  return addr;
}

/* Convert BUFFER, binary data at least LEN bytes long, into escaped
   binary data in OUT_BUF.  Set *OUT_LEN to the length of the data
   encoded in OUT_BUF, and return the number of bytes in OUT_BUF
   (which may be more than *OUT_LEN due to escape characters).  The
   total number of bytes in the output buffer will be at most
   OUT_MAXLEN.  */

static int
remote_escape_output (const gdb_byte *buffer, int len,
                      gdb_byte *out_buf, int *out_len,
                      int out_maxlen)
{
  int input_index, output_index;

  output_index = 0;
  for (input_index = 0; input_index < len; input_index++)
    {
      gdb_byte b = buffer[input_index];

      if (b == '$' || b == '#' || b == '}')
        {
          /* These must be escaped.  */
          if (output_index + 2 > out_maxlen)
            break;
          out_buf[output_index++] = '}';
          out_buf[output_index++] = b ^ 0x20;
        }
      else
        {
          if (output_index + 1 > out_maxlen)
            break;
          out_buf[output_index++] = b;
        }
    }

  *out_len = input_index;
  return output_index;
}

/* Convert BUFFER, escaped data LEN bytes long, into binary data
   in OUT_BUF.  Return the number of bytes written to OUT_BUF.
   Raise an error if the total number of bytes exceeds OUT_MAXLEN.

   This function reverses remote_escape_output.  It allows more
   escaped characters than that function does, in particular because
   '*' must be escaped to avoid the run-length encoding processing
   in reading packets.  */

static int
remote_unescape_input (const gdb_byte *buffer, int len,
                       gdb_byte *out_buf, int out_maxlen)
{
  int input_index, output_index;
  int escaped;

  output_index = 0;
  escaped = 0;
  for (input_index = 0; input_index < len; input_index++)
    {
      gdb_byte b = buffer[input_index];

      if (output_index + 1 > out_maxlen)
        {
          warning (_("Received too much data from remote target;"
                     " ignoring overflow."));
          return output_index;
        }

      if (escaped)
        {
          out_buf[output_index++] = b ^ 0x20;
          escaped = 0;
        }
      else if (b == '}')
        escaped = 1;
      else
        out_buf[output_index++] = b;
    }

  if (escaped)
    error (_("Unmatched escape character in target response."));

  return output_index;
}

/* Determine whether the remote target supports binary downloading.
   This is accomplished by sending a no-op memory write of zero length
   to the target at the specified address. It does not suffice to send
   the whole packet, since many stubs strip the eighth bit and
   subsequently compute a wrong checksum, which causes real havoc with
   remote_write_bytes.

   NOTE: This can still lose if the serial line is not eight-bit
   clean. In cases like this, the user should clear "remote
   X-packet".  */

static void
check_binary_download (CORE_ADDR addr)
{
  struct remote_state *rs = get_remote_state ();

  switch (remote_protocol_packets[PACKET_X].support)
    {
    case PACKET_DISABLE:
      break;
    case PACKET_ENABLE:
      break;
    case PACKET_SUPPORT_UNKNOWN:
      {
        char *p;

        p = rs->buf;
        *p++ = 'X';
        p += hexnumstr (p, (ULONGEST) addr);
        *p++ = ',';
        p += hexnumstr (p, (ULONGEST) 0);
        *p++ = ':';
        *p = '\0';

        putpkt_binary (rs->buf, (int) (p - rs->buf));
        getpkt (&rs->buf, &rs->buf_size, 0);

        if (rs->buf[0] == '\0')
          {
            if (remote_debug)
              fprintf_unfiltered (gdb_stdlog,
                                  "binary downloading NOT suppported by target\n");
            remote_protocol_packets[PACKET_X].support = PACKET_DISABLE;
          }
        else
          {
            if (remote_debug)
              fprintf_unfiltered (gdb_stdlog,
                                  "binary downloading suppported by target\n");
            remote_protocol_packets[PACKET_X].support = PACKET_ENABLE;
          }
        break;
      }
    }
}

/* Write memory data directly to the remote machine.
   This does not inform the data cache; the data cache uses this.
   HEADER is the starting part of the packet.
   MEMADDR is the address in the remote memory space.
   MYADDR is the address of the buffer in our space.
   LEN is the number of bytes.
   PACKET_FORMAT should be either 'X' or 'M', and indicates if we
   should send data as binary ('X'), or hex-encoded ('M').

   The function creates packet of the form
       <HEADER><ADDRESS>,<LENGTH>:<DATA>

   where encoding of <DATA> is termined by PACKET_FORMAT.

   If USE_LENGTH is 0, then the <LENGTH> field and the preceding comma
   are omitted.

   Returns the number of bytes transferred, or 0 (setting errno) for
   error.  Only transfer a single packet.  */

static int
remote_write_bytes_aux (const char *header, CORE_ADDR memaddr,
                        const gdb_byte *myaddr, int len,
                        char packet_format, int use_length)
{
  struct remote_state *rs = get_remote_state ();
  char *p;
  char *plen = NULL;
  int plenlen = 0;
  int todo;
  int nr_bytes;
  int payload_size;
  int payload_length;
  int header_length;

  if (packet_format != 'X' && packet_format != 'M')
    internal_error (__FILE__, __LINE__,
                    "remote_write_bytes_aux: bad packet format");

  if (len <= 0)
    return 0;

  payload_size = get_memory_write_packet_size ();

  /* The packet buffer will be large enough for the payload;
     get_memory_packet_size ensures this.  */
  rs->buf[0] = '\0';

  /* Compute the size of the actual payload by subtracting out the
     packet header and footer overhead: "$M<memaddr>,<len>:...#nn".
     */
  payload_size -= strlen ("$,:#NN");
  if (!use_length)
    /* The comma won't be used. */
    payload_size += 1;
  header_length = strlen (header);
  payload_size -= header_length;
  payload_size -= hexnumlen (memaddr);

  /* Construct the packet excluding the data: "<header><memaddr>,<len>:".  */

  strcat (rs->buf, header);
  p = rs->buf + strlen (header);

  /* Compute a best guess of the number of bytes actually transfered.  */
  if (packet_format == 'X')
    {
      /* Best guess at number of bytes that will fit.  */
      todo = min (len, payload_size);
      if (use_length)
        payload_size -= hexnumlen (todo);
      todo = min (todo, payload_size);
    }
  else
    {
      /* Num bytes that will fit.  */
      todo = min (len, payload_size / 2);
      if (use_length)
        payload_size -= hexnumlen (todo);
      todo = min (todo, payload_size / 2);
    }

  if (todo <= 0)
    internal_error (__FILE__, __LINE__,
                    _("minumum packet size too small to write data"));

  /* If we already need another packet, then try to align the end
     of this packet to a useful boundary.  */
  if (todo > 2 * REMOTE_ALIGN_WRITES && todo < len)
    todo = ((memaddr + todo) & ~(REMOTE_ALIGN_WRITES - 1)) - memaddr;

  /* Append "<memaddr>".  */
  memaddr = remote_address_masked (memaddr);
  p += hexnumstr (p, (ULONGEST) memaddr);

  if (use_length)
    {
      /* Append ",".  */
      *p++ = ',';

      /* Append <len>.  Retain the location/size of <len>.  It may need to
         be adjusted once the packet body has been created.  */
      plen = p;
      plenlen = hexnumstr (p, (ULONGEST) todo);
      p += plenlen;
    }

  /* Append ":".  */
  *p++ = ':';
  *p = '\0';

  /* Append the packet body.  */
  if (packet_format == 'X')
    {
      /* Binary mode.  Send target system values byte by byte, in
         increasing byte addresses.  Only escape certain critical
         characters.  */
      payload_length = remote_escape_output (myaddr, todo, p, &nr_bytes,
                                             payload_size);

      /* If not all TODO bytes fit, then we'll need another packet.  Make
         a second try to keep the end of the packet aligned.  Don't do
         this if the packet is tiny.  */
      if (nr_bytes < todo && nr_bytes > 2 * REMOTE_ALIGN_WRITES)
        {
          int new_nr_bytes;

          new_nr_bytes = (((memaddr + nr_bytes) & ~(REMOTE_ALIGN_WRITES - 1))
                          - memaddr);
          if (new_nr_bytes != nr_bytes)
            payload_length = remote_escape_output (myaddr, new_nr_bytes,
                                                   p, &nr_bytes,
                                                   payload_size);
        }

      p += payload_length;
      if (use_length && nr_bytes < todo)
        {
          /* Escape chars have filled up the buffer prematurely,
             and we have actually sent fewer bytes than planned.
             Fix-up the length field of the packet.  Use the same
             number of characters as before.  */
          plen += hexnumnstr (plen, (ULONGEST) nr_bytes, plenlen);
          *plen = ':';  /* overwrite \0 from hexnumnstr() */
        }
    }
  else
    {
      /* Normal mode: Send target system values byte by byte, in
         increasing byte addresses.  Each byte is encoded as a two hex
         value.  */
      nr_bytes = bin2hex (myaddr, p, todo);
      p += 2 * nr_bytes;
    }

  putpkt_binary (rs->buf, (int) (p - rs->buf));
  getpkt (&rs->buf, &rs->buf_size, 0);

  if (rs->buf[0] == 'E')
    {
      /* There is no correspondance between what the remote protocol
         uses for errors and errno codes.  We would like a cleaner way
         of representing errors (big enough to include errno codes,
         bfd_error codes, and others).  But for now just return EIO.  */
      errno = EIO;
      return 0;
    }

  /* Return NR_BYTES, not TODO, in case escape chars caused us to send
     fewer bytes than we'd planned.  */
  return nr_bytes;
}

/* Write memory data directly to the remote machine.
   This does not inform the data cache; the data cache uses this.
   MEMADDR is the address in the remote memory space.
   MYADDR is the address of the buffer in our space.
   LEN is the number of bytes.

   Returns number of bytes transferred, or 0 (setting errno) for
   error.  Only transfer a single packet.  */

int
remote_write_bytes (CORE_ADDR memaddr, const gdb_byte *myaddr, int len)
{
  char *packet_format = 0;

  /* Check whether the target supports binary download.  */
  check_binary_download (memaddr);

  switch (remote_protocol_packets[PACKET_X].support)
    {
    case PACKET_ENABLE:
      packet_format = "X";
      break;
    case PACKET_DISABLE:
      packet_format = "M";
      break;
    case PACKET_SUPPORT_UNKNOWN:
      internal_error (__FILE__, __LINE__,
                      _("remote_write_bytes: bad internal state"));
    default:
      internal_error (__FILE__, __LINE__, _("bad switch"));
    }

  return remote_write_bytes_aux (packet_format,
                                 memaddr, myaddr, len, packet_format[0], 1);
}

/* Read memory data directly from the remote machine.
   This does not use the data cache; the data cache uses this.
   MEMADDR is the address in the remote memory space.
   MYADDR is the address of the buffer in our space.
   LEN is the number of bytes.

   Returns number of bytes transferred, or 0 for error.  */

/* NOTE: cagney/1999-10-18: This function (and its siblings in other
   remote targets) shouldn't attempt to read the entire buffer.
   Instead it should read a single packet worth of data and then
   return the byte size of that packet to the caller.  The caller (its
   caller and its callers caller ;-) already contains code for
   handling partial reads.  */

int
remote_read_bytes (CORE_ADDR memaddr, gdb_byte *myaddr, int len)
{
  struct remote_state *rs = get_remote_state ();
  int max_buf_size;             /* Max size of packet output buffer.  */
  int origlen;

  if (len <= 0)
    return 0;

  max_buf_size = get_memory_read_packet_size ();
  /* The packet buffer will be large enough for the payload;
     get_memory_packet_size ensures this.  */

  origlen = len;
  while (len > 0)
    {
      char *p;
      int todo;
      int i;

      todo = min (len, max_buf_size / 2);       /* num bytes that will fit */

      /* construct "m"<memaddr>","<len>" */
      /* sprintf (rs->buf, "m%lx,%x", (unsigned long) memaddr, todo); */
      memaddr = remote_address_masked (memaddr);
      p = rs->buf;
      *p++ = 'm';
      p += hexnumstr (p, (ULONGEST) memaddr);
      *p++ = ',';
      p += hexnumstr (p, (ULONGEST) todo);
      *p = '\0';

      putpkt (rs->buf);
      getpkt (&rs->buf, &rs->buf_size, 0);

      if (rs->buf[0] == 'E'
          && isxdigit (rs->buf[1]) && isxdigit (rs->buf[2])
          && rs->buf[3] == '\0')
        {
          /* There is no correspondance between what the remote
             protocol uses for errors and errno codes.  We would like
             a cleaner way of representing errors (big enough to
             include errno codes, bfd_error codes, and others).  But
             for now just return EIO.  */
          errno = EIO;
          return 0;
        }

      /* Reply describes memory byte by byte,
         each byte encoded as two hex characters.  */

      p = rs->buf;
      if ((i = hex2bin (p, myaddr, todo)) < todo)
        {
          /* Reply is short.  This means that we were able to read
             only part of what we wanted to.  */
          return i + (origlen - len);
        }
      myaddr += todo;
      memaddr += todo;
      len -= todo;
    }
  return origlen;
}
\f

/* Remote notification handler.  */

static void
handle_notification (char *buf, size_t length)
{
  if (strncmp (buf, "Stop:", 5) == 0)
    {
      if (pending_stop_reply)
        /* We've already parsed the in-flight stop-reply, but the stub
           for some reason thought we didn't, possibly due to timeout
           on its side.  Just ignore it.  */
        ;
      else
        {
          struct cleanup *old_chain;
          struct stop_reply *reply = stop_reply_xmalloc ();
          old_chain = make_cleanup (do_stop_reply_xfree, reply);

          remote_parse_stop_reply (buf + 5, reply);

          discard_cleanups (old_chain);

          /* Be careful to only set it after parsing, since an error
             may be thrown then.  */
          pending_stop_reply = reply;

          /* Notify the event loop there's a stop reply to acknowledge
             and that there may be more events to fetch.  */
          mark_async_event_handler (remote_async_get_pending_events_token);
        }
    }
  else
    /* We ignore notifications we don't recognize, for compatibility
       with newer stubs.  */
    ;
}

\f
/* Read or write LEN bytes from inferior memory at MEMADDR,
   transferring to or from debugger address BUFFER.  Write to inferior
   if SHOULD_WRITE is nonzero.  Returns length of data written or
   read; 0 for error.  TARGET is unused.  */

static int
remote_xfer_memory (CORE_ADDR mem_addr, gdb_byte *buffer, int mem_len,
                    int should_write, struct mem_attrib *attrib,
                    struct target_ops *target)
{
  int res;

  set_general_thread (inferior_ptid);

  if (should_write)
    res = remote_write_bytes (mem_addr, buffer, mem_len);
  else
    res = remote_read_bytes (mem_addr, buffer, mem_len);

  return res;
}

/* Sends a packet with content determined by the printf format string
   FORMAT and the remaining arguments, then gets the reply.  Returns
   whether the packet was a success, a failure, or unknown.  */

enum packet_result
remote_send_printf (const char *format, ...)
{
  struct remote_state *rs = get_remote_state ();
  int max_size = get_remote_packet_size ();

  va_list ap;
  va_start (ap, format);

  rs->buf[0] = '\0';
  if (vsnprintf (rs->buf, max_size, format, ap) >= max_size)
    internal_error (__FILE__, __LINE__, "Too long remote packet.");

  if (putpkt (rs->buf) < 0)
    error (_("Communication problem with target."));

  rs->buf[0] = '\0';
  getpkt (&rs->buf, &rs->buf_size, 0);

  return packet_check_result (rs->buf);
}

static void
restore_remote_timeout (void *p)
{
  int value = *(int *)p;
  remote_timeout = value;
}

/* Flash writing can take quite some time.  We'll set
   effectively infinite timeout for flash operations.
   In future, we'll need to decide on a better approach.  */
static const int remote_flash_timeout = 1000;

static void
remote_flash_erase (struct target_ops *ops,
                    ULONGEST address, LONGEST length)
{
  int saved_remote_timeout = remote_timeout;
  enum packet_result ret;

  struct cleanup *back_to = make_cleanup (restore_remote_timeout,
                                          &saved_remote_timeout);
  remote_timeout = remote_flash_timeout;

  ret = remote_send_printf ("vFlashErase:%s,%s",
                            paddr (address),
                            phex (length, 4));
  switch (ret)
    {
    case PACKET_UNKNOWN:
      error (_("Remote target does not support flash erase"));
    case PACKET_ERROR:
      error (_("Error erasing flash with vFlashErase packet"));
    default:
      break;
    }

  do_cleanups (back_to);
}

static LONGEST
remote_flash_write (struct target_ops *ops,
                    ULONGEST address, LONGEST length,
                    const gdb_byte *data)
{
  int saved_remote_timeout = remote_timeout;
  int ret;
  struct cleanup *back_to = make_cleanup (restore_remote_timeout,
                                          &saved_remote_timeout);

  remote_timeout = remote_flash_timeout;
  ret = remote_write_bytes_aux ("vFlashWrite:", address, data, length, 'X', 0);
  do_cleanups (back_to);

  return ret;
}

static void
remote_flash_done (struct target_ops *ops)
{
  int saved_remote_timeout = remote_timeout;
  int ret;
  struct cleanup *back_to = make_cleanup (restore_remote_timeout,
                                          &saved_remote_timeout);

  remote_timeout = remote_flash_timeout;
  ret = remote_send_printf ("vFlashDone");
  do_cleanups (back_to);

  switch (ret)
    {
    case PACKET_UNKNOWN:
      error (_("Remote target does not support vFlashDone"));
    case PACKET_ERROR:
      error (_("Error finishing flash operation"));
    default:
      break;
    }
}

static void
remote_files_info (struct target_ops *ignore)
{
  puts_filtered ("Debugging a target over a serial line.\n");
}
\f
/* Stuff for dealing with the packets which are part of this protocol.
   See comment at top of file for details.  */

/* Read a single character from the remote end.  */

static int
readchar (int timeout)
{
  int ch;

  ch = serial_readchar (remote_desc, timeout);

  if (ch >= 0)
    return ch;

  switch ((enum serial_rc) ch)
    {
    case SERIAL_EOF:
      pop_target ();
      error (_("Remote connection closed"));
      /* no return */
    case SERIAL_ERROR:
      perror_with_name (_("Remote communication error"));
      /* no return */
    case SERIAL_TIMEOUT:
      break;
    }
  return ch;
}

/* Send the command in *BUF to the remote machine, and read the reply
   into *BUF.  Report an error if we get an error reply.  Resize
   *BUF using xrealloc if necessary to hold the result, and update
   *SIZEOF_BUF.  */

static void
remote_send (char **buf,
             long *sizeof_buf)
{
  putpkt (*buf);
  getpkt (buf, sizeof_buf, 0);

  if ((*buf)[0] == 'E')
    error (_("Remote failure reply: %s"), *buf);
}

/* Return a pointer to an xmalloc'ed string representing an escaped
   version of BUF, of len N.  E.g. \n is converted to \\n, \t to \\t,
   etc.  The caller is responsible for releasing the returned
   memory.  */

static char *
escape_buffer (const char *buf, int n)
{
  struct cleanup *old_chain;
  struct ui_file *stb;
  char *str;
  long length;

  stb = mem_fileopen ();
  old_chain = make_cleanup_ui_file_delete (stb);

  fputstrn_unfiltered (buf, n, 0, stb);
  str = ui_file_xstrdup (stb, &length);
  do_cleanups (old_chain);
  return str;
}

/* Display a null-terminated packet on stdout, for debugging, using C
   string notation.  */

static void
print_packet (char *buf)
{
  puts_filtered ("\"");
  fputstr_filtered (buf, '"', gdb_stdout);
  puts_filtered ("\"");
}

int
putpkt (char *buf)
{
  return putpkt_binary (buf, strlen (buf));
}

/* Send a packet to the remote machine, with error checking.  The data
   of the packet is in BUF.  The string in BUF can be at most
   get_remote_packet_size () - 5 to account for the $, # and checksum,
   and for a possible /0 if we are debugging (remote_debug) and want
   to print the sent packet as a string.  */

static int
putpkt_binary (char *buf, int cnt)
{
  struct remote_state *rs = get_remote_state ();
  int i;
  unsigned char csum = 0;
  char *buf2 = alloca (cnt + 6);

  int ch;
  int tcount = 0;
  char *p;

  /* Catch cases like trying to read memory or listing threads while
     we're waiting for a stop reply.  The remote server wouldn't be
     ready to handle this request, so we'd hang and timeout.  We don't
     have to worry about this in synchronous mode, because in that
     case it's not possible to issue a command while the target is
     running.  This is not a problem in non-stop mode, because in that
     case, the stub is always ready to process serial input.  */
  if (!non_stop && target_can_async_p () && rs->waiting_for_stop_reply)
    error (_("Cannot execute this command while the target is running."));

  /* We're sending out a new packet.  Make sure we don't look at a
     stale cached response.  */
  rs->cached_wait_status = 0;

  /* Copy the packet into buffer BUF2, encapsulating it
     and giving it a checksum.  */

  p = buf2;
  *p++ = '$';

  for (i = 0; i < cnt; i++)
    {
      csum += buf[i];
      *p++ = buf[i];
    }
  *p++ = '#';
  *p++ = tohex ((csum >> 4) & 0xf);
  *p++ = tohex (csum & 0xf);

  /* Send it over and over until we get a positive ack.  */

  while (1)
    {
      int started_error_output = 0;

      if (remote_debug)
        {
          struct cleanup *old_chain;
          char *str;

          *p = '\0';
          str = escape_buffer (buf2, p - buf2);
          old_chain = make_cleanup (xfree, str);
          fprintf_unfiltered (gdb_stdlog, "Sending packet: %s...", str);
          gdb_flush (gdb_stdlog);
          do_cleanups (old_chain);
        }
      if (serial_write (remote_desc, buf2, p - buf2))
        perror_with_name (_("putpkt: write failed"));

      /* If this is a no acks version of the remote protocol, send the
         packet and move on.  */
      if (rs->noack_mode)
        break;

      /* Read until either a timeout occurs (-2) or '+' is read.
         Handle any notification that arrives in the mean time.  */
      while (1)
        {
          ch = readchar (remote_timeout);

          if (remote_debug)
            {
              switch (ch)
                {
                case '+':
                case '-':
                case SERIAL_TIMEOUT:
                case '$':
                case '%':
                  if (started_error_output)
                    {
                      putchar_unfiltered ('\n');
                      started_error_output = 0;
                    }
                }
            }

          switch (ch)
            {
            case '+':
              if (remote_debug)
                fprintf_unfiltered (gdb_stdlog, "Ack\n");
              return 1;
            case '-':
              if (remote_debug)
                fprintf_unfiltered (gdb_stdlog, "Nak\n");
            case SERIAL_TIMEOUT:
              tcount++;
              if (tcount > 3)
                return 0;
              break;            /* Retransmit buffer.  */
            case '$':
              {
                if (remote_debug)
                  fprintf_unfiltered (gdb_stdlog,
                                      "Packet instead of Ack, ignoring it\n");
                /* It's probably an old response sent because an ACK
                   was lost.  Gobble up the packet and ack it so it
                   doesn't get retransmitted when we resend this
                   packet.  */
                skip_frame ();
                serial_write (remote_desc, "+", 1);
                continue;       /* Now, go look for +.  */
              }

            case '%':
              {
                int val;

                /* If we got a notification, handle it, and go back to looking
                   for an ack.  */
                /* We've found the start of a notification.  Now
                   collect the data.  */
                val = read_frame (&rs->buf, &rs->buf_size);
                if (val >= 0)
                  {
                    if (remote_debug)
                      {
                        struct cleanup *old_chain;
                        char *str;

                        str = escape_buffer (rs->buf, val);
                        old_chain = make_cleanup (xfree, str);
                        fprintf_unfiltered (gdb_stdlog,
                                            "  Notification received: %s\n",
                                            str);
                        do_cleanups (old_chain);
                      }
                    handle_notification (rs->buf, val);
                    /* We're in sync now, rewait for the ack.  */
                    tcount = 0;
                  }
                else
                  {
                    if (remote_debug)
                      {
                        if (!started_error_output)
                          {
                            started_error_output = 1;
                            fprintf_unfiltered (gdb_stdlog, "putpkt: Junk: ");
                          }
                        fputc_unfiltered (ch & 0177, gdb_stdlog);
                        fprintf_unfiltered (gdb_stdlog, "%s", rs->buf);
                      }
                  }
                continue;
              }
              /* fall-through */
            default:
              if (remote_debug)
                {
                  if (!started_error_output)
                    {
                      started_error_output = 1;
                      fprintf_unfiltered (gdb_stdlog, "putpkt: Junk: ");
                    }
                  fputc_unfiltered (ch & 0177, gdb_stdlog);
                }
              continue;
            }
          break;                /* Here to retransmit.  */
        }

#if 0
      /* This is wrong.  If doing a long backtrace, the user should be
         able to get out next time we call QUIT, without anything as
         violent as interrupt_query.  If we want to provide a way out of
         here without getting to the next QUIT, it should be based on
         hitting ^C twice as in remote_wait.  */
      if (quit_flag)
        {
          quit_flag = 0;
          interrupt_query ();
        }
#endif
    }
  return 0;
}

/* Come here after finding the start of a frame when we expected an
   ack.  Do our best to discard the rest of this packet.  */

static void
skip_frame (void)
{
  int c;

  while (1)
    {
      c = readchar (remote_timeout);
      switch (c)
        {
        case SERIAL_TIMEOUT:
          /* Nothing we can do.  */
          return;
        case '#':
          /* Discard the two bytes of checksum and stop.  */
          c = readchar (remote_timeout);
          if (c >= 0)
            c = readchar (remote_timeout);

          return;
        case '*':               /* Run length encoding.  */
          /* Discard the repeat count.  */
          c = readchar (remote_timeout);
          if (c < 0)
            return;
          break;
        default:
          /* A regular character.  */
          break;
        }
    }
}

/* Come here after finding the start of the frame.  Collect the rest
   into *BUF, verifying the checksum, length, and handling run-length
   compression.  NUL terminate the buffer.  If there is not enough room,
   expand *BUF using xrealloc.

   Returns -1 on error, number of characters in buffer (ignoring the
   trailing NULL) on success. (could be extended to return one of the
   SERIAL status indications).  */

static long
read_frame (char **buf_p,
            long *sizeof_buf)
{
  unsigned char csum;
  long bc;
  int c;
  char *buf = *buf_p;
  struct remote_state *rs = get_remote_state ();

  csum = 0;
  bc = 0;

  while (1)
    {
      c = readchar (remote_timeout);
      switch (c)
        {
        case SERIAL_TIMEOUT:
          if (remote_debug)
            fputs_filtered ("Timeout in mid-packet, retrying\n", gdb_stdlog);
          return -1;
        case '$':
          if (remote_debug)
            fputs_filtered ("Saw new packet start in middle of old one\n",
                            gdb_stdlog);
          return -1;            /* Start a new packet, count retries.  */
        case '#':
          {
            unsigned char pktcsum;
            int check_0 = 0;
            int check_1 = 0;

            buf[bc] = '\0';

            check_0 = readchar (remote_timeout);
            if (check_0 >= 0)
              check_1 = readchar (remote_timeout);

            if (check_0 == SERIAL_TIMEOUT || check_1 == SERIAL_TIMEOUT)
              {
                if (remote_debug)
                  fputs_filtered ("Timeout in checksum, retrying\n",
                                  gdb_stdlog);
                return -1;
              }
            else if (check_0 < 0 || check_1 < 0)
              {
                if (remote_debug)
                  fputs_filtered ("Communication error in checksum\n",
                                  gdb_stdlog);
                return -1;
              }

            /* Don't recompute the checksum; with no ack packets we
               don't have any way to indicate a packet retransmission
               is necessary.  */
            if (rs->noack_mode)
              return bc;

            pktcsum = (fromhex (check_0) << 4) | fromhex (check_1);
            if (csum == pktcsum)
              return bc;

            if (remote_debug)
              {
                struct cleanup *old_chain;
                char *str;

                str = escape_buffer (buf, bc);
                old_chain = make_cleanup (xfree, str);
                fprintf_unfiltered (gdb_stdlog,
                                    "\
Bad checksum, sentsum=0x%x, csum=0x%x, buf=%s\n",
                                    pktcsum, csum, str);
                do_cleanups (old_chain);
              }
            /* Number of characters in buffer ignoring trailing
               NULL.  */
            return -1;
          }
        case '*':               /* Run length encoding.  */
          {
            int repeat;
            csum += c;

            c = readchar (remote_timeout);
            csum += c;
            repeat = c - ' ' + 3;       /* Compute repeat count.  */

            /* The character before ``*'' is repeated.  */

            if (repeat > 0 && repeat <= 255 && bc > 0)
              {
                if (bc + repeat - 1 >= *sizeof_buf - 1)
                  {
                    /* Make some more room in the buffer.  */
                    *sizeof_buf += repeat;
                    *buf_p = xrealloc (*buf_p, *sizeof_buf);
                    buf = *buf_p;
                  }

                memset (&buf[bc], buf[bc - 1], repeat);
                bc += repeat;
                continue;
              }

            buf[bc] = '\0';
            printf_filtered (_("Invalid run length encoding: %s\n"), buf);
            return -1;
          }
        default:
          if (bc >= *sizeof_buf - 1)
            {
              /* Make some more room in the buffer.  */
              *sizeof_buf *= 2;
              *buf_p = xrealloc (*buf_p, *sizeof_buf);
              buf = *buf_p;
            }

          buf[bc++] = c;
          csum += c;
          continue;
        }
    }
}

/* Read a packet from the remote machine, with error checking, and
   store it in *BUF.  Resize *BUF using xrealloc if necessary to hold
   the result, and update *SIZEOF_BUF.  If FOREVER, wait forever
   rather than timing out; this is used (in synchronous mode) to wait
   for a target that is is executing user code to stop.  */
/* FIXME: ezannoni 2000-02-01 this wrapper is necessary so that we
   don't have to change all the calls to getpkt to deal with the
   return value, because at the moment I don't know what the right
   thing to do it for those.  */
void
getpkt (char **buf,
        long *sizeof_buf,
        int forever)
{
  int timed_out;

  timed_out = getpkt_sane (buf, sizeof_buf, forever);
}


/* Read a packet from the remote machine, with error checking, and
   store it in *BUF.  Resize *BUF using xrealloc if necessary to hold
   the result, and update *SIZEOF_BUF.  If FOREVER, wait forever
   rather than timing out; this is used (in synchronous mode) to wait
   for a target that is is executing user code to stop.  If FOREVER ==
   0, this function is allowed to time out gracefully and return an
   indication of this to the caller.  Otherwise return the number of
   bytes read.  If EXPECTING_NOTIF, consider receiving a notification
   enough reason to return to the caller.  */

static int
getpkt_or_notif_sane_1 (char **buf, long *sizeof_buf, int forever,
                        int expecting_notif)
{
  struct remote_state *rs = get_remote_state ();
  int c;
  int tries;
  int timeout;
  int val;

  /* We're reading a new response.  Make sure we don't look at a
     previously cached response.  */
  rs->cached_wait_status = 0;

  strcpy (*buf, "timeout");

  if (forever)
    timeout = watchdog > 0 ? watchdog : -1;
  else if (expecting_notif)
    timeout = 0; /* There should already be a char in the buffer.  If
                    not, bail out.  */
  else
    timeout = remote_timeout;

#define MAX_TRIES 3

  /* Process any number of notifications, and then return when
     we get a packet.  */
  for (;;)
    {
      /* If we get a timeout or bad checksm, retry up to MAX_TRIES
         times.  */
      for (tries = 1; tries <= MAX_TRIES; tries++)
        {
          /* This can loop forever if the remote side sends us
             characters continuously, but if it pauses, we'll get
             SERIAL_TIMEOUT from readchar because of timeout.  Then
             we'll count that as a retry.

             Note that even when forever is set, we will only wait
             forever prior to the start of a packet.  After that, we
             expect characters to arrive at a brisk pace.  They should
             show up within remote_timeout intervals.  */
          do
            c = readchar (timeout);
          while (c != SERIAL_TIMEOUT && c != '$' && c != '%');

          if (c == SERIAL_TIMEOUT)
            {
              if (expecting_notif)
                return -1; /* Don't complain, it's normal to not get
                              anything in this case.  */

              if (forever)      /* Watchdog went off?  Kill the target.  */
                {
                  QUIT;
                  pop_target ();
                  error (_("Watchdog timeout has expired.  Target detached."));
                }
              if (remote_debug)
                fputs_filtered ("Timed out.\n", gdb_stdlog);
            }
          else
            {
              /* We've found the start of a packet or notification.
                 Now collect the data.  */
              val = read_frame (buf, sizeof_buf);
              if (val >= 0)
                break;
            }

          serial_write (remote_desc, "-", 1);
        }

      if (tries > MAX_TRIES)
        {
          /* We have tried hard enough, and just can't receive the
             packet/notification.  Give up.  */
          printf_unfiltered (_("Ignoring packet error, continuing...\n"));

          /* Skip the ack char if we're in no-ack mode.  */
          if (!rs->noack_mode)
            serial_write (remote_desc, "+", 1);
          return -1;
        }

      /* If we got an ordinary packet, return that to our caller.  */
      if (c == '$')
        {
          if (remote_debug)
            {
             struct cleanup *old_chain;
             char *str;

             str = escape_buffer (*buf, val);
             old_chain = make_cleanup (xfree, str);
             fprintf_unfiltered (gdb_stdlog, "Packet received: %s\n", str);
             do_cleanups (old_chain);
            }

          /* Skip the ack char if we're in no-ack mode.  */
          if (!rs->noack_mode)
            serial_write (remote_desc, "+", 1);
          return val;
        }

       /* If we got a notification, handle it, and go back to looking
         for a packet.  */
      else
        {
          gdb_assert (c == '%');

          if (remote_debug)
            {
              struct cleanup *old_chain;
              char *str;

              str = escape_buffer (*buf, val);
              old_chain = make_cleanup (xfree, str);
              fprintf_unfiltered (gdb_stdlog,
                                  "  Notification received: %s\n",
                                  str);
              do_cleanups (old_chain);
            }

          handle_notification (*buf, val);

          /* Notifications require no acknowledgement.  */

          if (expecting_notif)
            return -1;
        }
    }
}

static int
getpkt_sane (char **buf, long *sizeof_buf, int forever)
{
  return getpkt_or_notif_sane_1 (buf, sizeof_buf, forever, 0);
}

static int
getpkt_or_notif_sane (char **buf, long *sizeof_buf, int forever)
{
  return getpkt_or_notif_sane_1 (buf, sizeof_buf, forever, 1);
}

\f
static void
remote_kill (void)
{
  /* Use catch_errors so the user can quit from gdb even when we
     aren't on speaking terms with the remote system.  */
  catch_errors ((catch_errors_ftype *) putpkt, "k", "", RETURN_MASK_ERROR);

  /* Don't wait for it to die.  I'm not really sure it matters whether
     we do or not.  For the existing stubs, kill is a noop.  */
  target_mourn_inferior ();
}

static int
remote_vkill (int pid, struct remote_state *rs)
{
  if (remote_protocol_packets[PACKET_vKill].support == PACKET_DISABLE)
    return -1;

  /* Tell the remote target to detach.  */
  sprintf (rs->buf, "vKill;%x", pid);
  putpkt (rs->buf);
  getpkt (&rs->buf, &rs->buf_size, 0);

  if (packet_ok (rs->buf,
                 &remote_protocol_packets[PACKET_vKill]) == PACKET_OK)
    return 0;
  else if (remote_protocol_packets[PACKET_vKill].support == PACKET_DISABLE)
    return -1;
  else
    return 1;
}

static void
extended_remote_kill (void)
{
  int res;
  int pid = ptid_get_pid (inferior_ptid);
  struct remote_state *rs = get_remote_state ();

  res = remote_vkill (pid, rs);
  if (res == -1 && !remote_multi_process_p (rs))
    {
      /* Don't try 'k' on a multi-process aware stub -- it has no way
         to specify the pid.  */

      putpkt ("k");
#if 0
      getpkt (&rs->buf, &rs->buf_size, 0);
      if (rs->buf[0] != 'O' || rs->buf[0] != 'K')
        res = 1;
#else
      /* Don't wait for it to die.  I'm not really sure it matters whether
         we do or not.  For the existing stubs, kill is a noop.  */
      res = 0;
#endif
    }

  if (res != 0)
    error (_("Can't kill process"));

  delete_inferior (pid);
  target_mourn_inferior ();
}

static void
remote_mourn (struct target_ops *ops)
{
  remote_mourn_1 (ops);
}

/* Worker function for remote_mourn.  */
static void
remote_mourn_1 (struct target_ops *target)
{
  unpush_target (target);

  /* remote_close takes care of cleaning up.  */
}

static int
select_new_thread_callback (struct thread_info *th, void* data)
{
  if (!is_exited (th->ptid))
    {
      switch_to_thread (th->ptid);
      printf_filtered (_("[Switching to %s]\n"),
                       target_pid_to_str (inferior_ptid));
      return 1;
    }
  return 0;
}

static void
extended_remote_mourn_1 (struct target_ops *target)
{
  struct remote_state *rs = get_remote_state ();

  /* In case we got here due to an error, but we're going to stay
     connected.  */
  rs->waiting_for_stop_reply = 0;

  /* We're no longer interested in these events.  */
  discard_pending_stop_replies (ptid_get_pid (inferior_ptid));

  /* Unlike "target remote", we do not want to unpush the target; then
     the next time the user says "run", we won't be connected.  */

  if (have_inferiors ())
    {
      extern void nullify_last_target_wait_ptid ();
      /* Multi-process case.  The current process has exited, but
         there are other processes to debug.  Switch to the first
         available.  */
      iterate_over_threads (select_new_thread_callback, NULL);
      nullify_last_target_wait_ptid ();
    }
  else
    {
      struct remote_state *rs = get_remote_state ();

      /* Call common code to mark the inferior as not running.  */
      generic_mourn_inferior ();
      if (!remote_multi_process_p (rs))
        {
          /* Check whether the target is running now - some remote stubs
             automatically restart after kill.  */
          putpkt ("?");
          getpkt (&rs->buf, &rs->buf_size, 0);

          if (rs->buf[0] == 'S' || rs->buf[0] == 'T')
            {
              /* Assume that the target has been restarted.  Set inferior_ptid
                 so that bits of core GDB realizes there's something here, e.g.,
                 so that the user can say "kill" again.  */
              inferior_ptid = magic_null_ptid;
            }
          else
            {
              /* Mark this (still pushed) target as not executable until we
                 restart it.  */
              target_mark_exited (target);
            }
        }
      else
        /* Always remove execution if this was the last process.  */
        target_mark_exited (target);
    }
}

static void
extended_remote_mourn (struct target_ops *ops)
{
  extended_remote_mourn_1 (ops);
}

static int
extended_remote_run (char *args)
{
  struct remote_state *rs = get_remote_state ();
  char *p;
  int len;

  /* If the user has disabled vRun support, or we have detected that
     support is not available, do not try it.  */
  if (remote_protocol_packets[PACKET_vRun].support == PACKET_DISABLE)
    return -1;

  strcpy (rs->buf, "vRun;");
  len = strlen (rs->buf);

  if (strlen (remote_exec_file) * 2 + len >= get_remote_packet_size ())
    error (_("Remote file name too long for run packet"));
  len += 2 * bin2hex ((gdb_byte *) remote_exec_file, rs->buf + len, 0);

  gdb_assert (args != NULL);
  if (*args)
    {
      struct cleanup *back_to;
      int i;
      char **argv;

      argv = gdb_buildargv (args);
      back_to = make_cleanup ((void (*) (void *)) freeargv, argv);
      for (i = 0; argv[i] != NULL; i++)
        {
          if (strlen (argv[i]) * 2 + 1 + len >= get_remote_packet_size ())
            error (_("Argument list too long for run packet"));
          rs->buf[len++] = ';';
          len += 2 * bin2hex ((gdb_byte *) argv[i], rs->buf + len, 0);
        }
      do_cleanups (back_to);
    }

  rs->buf[len++] = '\0';

  putpkt (rs->buf);
  getpkt (&rs->buf, &rs->buf_size, 0);

  if (packet_ok (rs->buf, &remote_protocol_packets[PACKET_vRun]) == PACKET_OK)
    {
      /* We have a wait response; we don't need it, though.  All is well.  */
      return 0;
    }
  else if (remote_protocol_packets[PACKET_vRun].support == PACKET_DISABLE)
    /* It wasn't disabled before, but it is now.  */
    return -1;
  else
    {
      if (remote_exec_file[0] == '\0')
        error (_("Running the default executable on the remote target failed; "
                 "try \"set remote exec-file\"?"));
      else
        error (_("Running \"%s\" on the remote target failed"),
               remote_exec_file);
    }
}

/* In the extended protocol we want to be able to do things like
   "run" and have them basically work as expected.  So we need
   a special create_inferior function.  We support changing the
   executable file and the command line arguments, but not the
   environment.  */

static void
extended_remote_create_inferior_1 (char *exec_file, char *args,
                                   char **env, int from_tty)
{
  /* If running asynchronously, register the target file descriptor
     with the event loop.  */
  if (target_can_async_p ())
    target_async (inferior_event_handler, 0);

  /* Now restart the remote server.  */
  if (extended_remote_run (args) == -1)
    {
      /* vRun was not supported.  Fail if we need it to do what the
         user requested.  */
      if (remote_exec_file[0])
        error (_("Remote target does not support \"set remote exec-file\""));
      if (args[0])
        error (_("Remote target does not support \"set args\" or run <ARGS>"));

      /* Fall back to "R".  */
      extended_remote_restart ();
    }

  /* Clean up from the last time we ran, before we mark the target
     running again.  This will mark breakpoints uninserted, and
     get_offsets may insert breakpoints.  */
  init_thread_list ();
  init_wait_for_inferior ();

  /* Now mark the inferior as running before we do anything else.  */
  inferior_ptid = magic_null_ptid;

  /* Now, if we have thread information, update inferior_ptid.  */
  inferior_ptid = remote_current_thread (inferior_ptid);

  add_inferior (ptid_get_pid (inferior_ptid));
  add_thread_silent (inferior_ptid);

  target_mark_running (&extended_remote_ops);

  /* Get updated offsets, if the stub uses qOffsets.  */
  get_offsets ();
}

static void
extended_remote_create_inferior (struct target_ops *ops, 
                                 char *exec_file, char *args,
                                 char **env, int from_tty)
{
  extended_remote_create_inferior_1 (exec_file, args, env, from_tty);
}
\f

/* Insert a breakpoint.  On targets that have software breakpoint
   support, we ask the remote target to do the work; on targets
   which don't, we insert a traditional memory breakpoint.  */

static int
remote_insert_breakpoint (struct bp_target_info *bp_tgt)
{
  /* Try the "Z" s/w breakpoint packet if it is not already disabled.
     If it succeeds, then set the support to PACKET_ENABLE.  If it
     fails, and the user has explicitly requested the Z support then
     report an error, otherwise, mark it disabled and go on.  */

  if (remote_protocol_packets[PACKET_Z0].support != PACKET_DISABLE)
    {
      CORE_ADDR addr = bp_tgt->placed_address;
      struct remote_state *rs;
      char *p;
      int bpsize;

      gdbarch_breakpoint_from_pc (target_gdbarch, &addr, &bpsize);

      rs = get_remote_state ();
      p = rs->buf;

      *(p++) = 'Z';
      *(p++) = '0';
      *(p++) = ',';
      addr = (ULONGEST) remote_address_masked (addr);
      p += hexnumstr (p, addr);
      sprintf (p, ",%d", bpsize);

      putpkt (rs->buf);
      getpkt (&rs->buf, &rs->buf_size, 0);

      switch (packet_ok (rs->buf, &remote_protocol_packets[PACKET_Z0]))
        {
        case PACKET_ERROR:
          return -1;
        case PACKET_OK:
          bp_tgt->placed_address = addr;
          bp_tgt->placed_size = bpsize;
          return 0;
        case PACKET_UNKNOWN:
          break;
        }
    }

  return memory_insert_breakpoint (bp_tgt);
}

static int
remote_remove_breakpoint (struct bp_target_info *bp_tgt)
{
  CORE_ADDR addr = bp_tgt->placed_address;
  struct remote_state *rs = get_remote_state ();
  int bp_size;

  if (remote_protocol_packets[PACKET_Z0].support != PACKET_DISABLE)
    {
      char *p = rs->buf;

      *(p++) = 'z';
      *(p++) = '0';
      *(p++) = ',';

      addr = (ULONGEST) remote_address_masked (bp_tgt->placed_address);
      p += hexnumstr (p, addr);
      sprintf (p, ",%d", bp_tgt->placed_size);

      putpkt (rs->buf);
      getpkt (&rs->buf, &rs->buf_size, 0);

      return (rs->buf[0] == 'E');
    }

  return memory_remove_breakpoint (bp_tgt);
}

static int
watchpoint_to_Z_packet (int type)
{
  switch (type)
    {
    case hw_write:
      return Z_PACKET_WRITE_WP;
      break;
    case hw_read:
      return Z_PACKET_READ_WP;
      break;
    case hw_access:
      return Z_PACKET_ACCESS_WP;
      break;
    default:
      internal_error (__FILE__, __LINE__,
                      _("hw_bp_to_z: bad watchpoint type %d"), type);
    }
}

static int
remote_insert_watchpoint (CORE_ADDR addr, int len, int type)
{
  struct remote_state *rs = get_remote_state ();
  char *p;
  enum Z_packet_type packet = watchpoint_to_Z_packet (type);

  if (remote_protocol_packets[PACKET_Z0 + packet].support == PACKET_DISABLE)
    return -1;

  sprintf (rs->buf, "Z%x,", packet);
  p = strchr (rs->buf, '\0');
  addr = remote_address_masked (addr);
  p += hexnumstr (p, (ULONGEST) addr);
  sprintf (p, ",%x", len);

  putpkt (rs->buf);
  getpkt (&rs->buf, &rs->buf_size, 0);

  switch (packet_ok (rs->buf, &remote_protocol_packets[PACKET_Z0 + packet]))
    {
    case PACKET_ERROR:
    case PACKET_UNKNOWN:
      return -1;
    case PACKET_OK:
      return 0;
    }
  internal_error (__FILE__, __LINE__,
                  _("remote_insert_watchpoint: reached end of function"));
}


static int
remote_remove_watchpoint (CORE_ADDR addr, int len, int type)
{
  struct remote_state *rs = get_remote_state ();
  char *p;
  enum Z_packet_type packet = watchpoint_to_Z_packet (type);

  if (remote_protocol_packets[PACKET_Z0 + packet].support == PACKET_DISABLE)
    return -1;

  sprintf (rs->buf, "z%x,", packet);
  p = strchr (rs->buf, '\0');
  addr = remote_address_masked (addr);
  p += hexnumstr (p, (ULONGEST) addr);
  sprintf (p, ",%x", len);
  putpkt (rs->buf);
  getpkt (&rs->buf, &rs->buf_size, 0);

  switch (packet_ok (rs->buf, &remote_protocol_packets[PACKET_Z0 + packet]))
    {
    case PACKET_ERROR:
    case PACKET_UNKNOWN:
      return -1;
    case PACKET_OK:
      return 0;
    }
  internal_error (__FILE__, __LINE__,
                  _("remote_remove_watchpoint: reached end of function"));
}


int remote_hw_watchpoint_limit = -1;
int remote_hw_breakpoint_limit = -1;

static int
remote_check_watch_resources (int type, int cnt, int ot)
{
  if (type == bp_hardware_breakpoint)
    {
      if (remote_hw_breakpoint_limit == 0)
        return 0;
      else if (remote_hw_breakpoint_limit < 0)
        return 1;
      else if (cnt <= remote_hw_breakpoint_limit)
        return 1;
    }
  else
    {
      if (remote_hw_watchpoint_limit == 0)
        return 0;
      else if (remote_hw_watchpoint_limit < 0)
        return 1;
      else if (ot)
        return -1;
      else if (cnt <= remote_hw_watchpoint_limit)
        return 1;
    }
  return -1;
}

static int
remote_stopped_by_watchpoint (void)
{
  return remote_stopped_by_watchpoint_p;
}

static int
remote_stopped_data_address (struct target_ops *target, CORE_ADDR *addr_p)
{
  int rc = 0;
  if (remote_stopped_by_watchpoint ())
    {
      *addr_p = remote_watch_data_address;
      rc = 1;
    }

  return rc;
}


static int
remote_insert_hw_breakpoint (struct bp_target_info *bp_tgt)
{
  CORE_ADDR addr;
  struct remote_state *rs;
  char *p;

  /* The length field should be set to the size of a breakpoint
     instruction, even though we aren't inserting one ourselves.  */

  gdbarch_breakpoint_from_pc
    (target_gdbarch, &bp_tgt->placed_address, &bp_tgt->placed_size);

  if (remote_protocol_packets[PACKET_Z1].support == PACKET_DISABLE)
    return -1;

  rs = get_remote_state ();
  p = rs->buf;

  *(p++) = 'Z';
  *(p++) = '1';
  *(p++) = ',';

  addr = remote_address_masked (bp_tgt->placed_address);
  p += hexnumstr (p, (ULONGEST) addr);
  sprintf (p, ",%x", bp_tgt->placed_size);

  putpkt (rs->buf);
  getpkt (&rs->buf, &rs->buf_size, 0);

  switch (packet_ok (rs->buf, &remote_protocol_packets[PACKET_Z1]))
    {
    case PACKET_ERROR:
    case PACKET_UNKNOWN:
      return -1;
    case PACKET_OK:
      return 0;
    }
  internal_error (__FILE__, __LINE__,
                  _("remote_insert_hw_breakpoint: reached end of function"));
}


static int
remote_remove_hw_breakpoint (struct bp_target_info *bp_tgt)
{
  CORE_ADDR addr;
  struct remote_state *rs = get_remote_state ();
  char *p = rs->buf;

  if (remote_protocol_packets[PACKET_Z1].support == PACKET_DISABLE)
    return -1;

  *(p++) = 'z';
  *(p++) = '1';
  *(p++) = ',';

  addr = remote_address_masked (bp_tgt->placed_address);
  p += hexnumstr (p, (ULONGEST) addr);
  sprintf (p, ",%x", bp_tgt->placed_size);

  putpkt (rs->buf);
  getpkt (&rs->buf, &rs->buf_size, 0);

  switch (packet_ok (rs->buf, &remote_protocol_packets[PACKET_Z1]))
    {
    case PACKET_ERROR:
    case PACKET_UNKNOWN:
      return -1;
    case PACKET_OK:
      return 0;
    }
  internal_error (__FILE__, __LINE__,
                  _("remote_remove_hw_breakpoint: reached end of function"));
}

/* Table used by the crc32 function to calcuate the checksum.  */

static unsigned long crc32_table[256] =
{0, 0};

static unsigned long
crc32 (unsigned char *buf, int len, unsigned int crc)
{
  if (!crc32_table[1])
    {
      /* Initialize the CRC table and the decoding table.  */
      int i, j;
      unsigned int c;

      for (i = 0; i < 256; i++)
        {
          for (c = i << 24, j = 8; j > 0; --j)
            c = c & 0x80000000 ? (c << 1) ^ 0x04c11db7 : (c << 1);
          crc32_table[i] = c;
        }
    }

  while (len--)
    {
      crc = (crc << 8) ^ crc32_table[((crc >> 24) ^ *buf) & 255];
      buf++;
    }
  return crc;
}

/* compare-sections command

   With no arguments, compares each loadable section in the exec bfd
   with the same memory range on the target, and reports mismatches.
   Useful for verifying the image on the target against the exec file.
   Depends on the target understanding the new "qCRC:" request.  */

/* FIXME: cagney/1999-10-26: This command should be broken down into a
   target method (target verify memory) and generic version of the
   actual command.  This will allow other high-level code (especially
   generic_load()) to make use of this target functionality.  */

static void
compare_sections_command (char *args, int from_tty)
{
  struct remote_state *rs = get_remote_state ();
  asection *s;
  unsigned long host_crc, target_crc;
  extern bfd *exec_bfd;
  struct cleanup *old_chain;
  char *tmp;
  char *sectdata;
  const char *sectname;
  bfd_size_type size;
  bfd_vma lma;
  int matched = 0;
  int mismatched = 0;

  if (!exec_bfd)
    error (_("command cannot be used without an exec file"));
  if (!current_target.to_shortname ||
      strcmp (current_target.to_shortname, "remote") != 0)
    error (_("command can only be used with remote target"));

  for (s = exec_bfd->sections; s; s = s->next)
    {
      if (!(s->flags & SEC_LOAD))
        continue;               /* skip non-loadable section */

      size = bfd_get_section_size (s);
      if (size == 0)
        continue;               /* skip zero-length section */

      sectname = bfd_get_section_name (exec_bfd, s);
      if (args && strcmp (args, sectname) != 0)
        continue;               /* not the section selected by user */

      matched = 1;              /* do this section */
      lma = s->lma;
      /* FIXME: assumes lma can fit into long.  */
      xsnprintf (rs->buf, get_remote_packet_size (), "qCRC:%lx,%lx",
                 (long) lma, (long) size);
      putpkt (rs->buf);

      /* Be clever; compute the host_crc before waiting for target
         reply.  */
      sectdata = xmalloc (size);
      old_chain = make_cleanup (xfree, sectdata);
      bfd_get_section_contents (exec_bfd, s, sectdata, 0, size);
      host_crc = crc32 ((unsigned char *) sectdata, size, 0xffffffff);

      getpkt (&rs->buf, &rs->buf_size, 0);
      if (rs->buf[0] == 'E')
        error (_("target memory fault, section %s, range 0x%s -- 0x%s"),
               sectname, paddr (lma), paddr (lma + size));
      if (rs->buf[0] != 'C')
        error (_("remote target does not support this operation"));

      for (target_crc = 0, tmp = &rs->buf[1]; *tmp; tmp++)
        target_crc = target_crc * 16 + fromhex (*tmp);

      printf_filtered ("Section %s, range 0x%s -- 0x%s: ",
                       sectname, paddr (lma), paddr (lma + size));
      if (host_crc == target_crc)
        printf_filtered ("matched.\n");
      else
        {
          printf_filtered ("MIS-MATCHED!\n");
          mismatched++;
        }

      do_cleanups (old_chain);
    }
  if (mismatched > 0)
    warning (_("One or more sections of the remote executable does not match\n\
the loaded file\n"));
  if (args && !matched)
    printf_filtered (_("No loaded section named '%s'.\n"), args);
}

/* Write LEN bytes from WRITEBUF into OBJECT_NAME/ANNEX at OFFSET
   into remote target.  The number of bytes written to the remote
   target is returned, or -1 for error.  */

static LONGEST
remote_write_qxfer (struct target_ops *ops, const char *object_name,
                    const char *annex, const gdb_byte *writebuf, 
                    ULONGEST offset, LONGEST len, 
                    struct packet_config *packet)
{
  int i, buf_len;
  ULONGEST n;
  gdb_byte *wbuf;
  struct remote_state *rs = get_remote_state ();
  int max_size = get_memory_write_packet_size (); 

  if (packet->support == PACKET_DISABLE)
    return -1;

  /* Insert header.  */
  i = snprintf (rs->buf, max_size, 
                "qXfer:%s:write:%s:%s:",
                object_name, annex ? annex : "",
                phex_nz (offset, sizeof offset));
  max_size -= (i + 1);

  /* Escape as much data as fits into rs->buf.  */
  buf_len = remote_escape_output 
    (writebuf, len, (rs->buf + i), &max_size, max_size);

  if (putpkt_binary (rs->buf, i + buf_len) < 0
      || getpkt_sane (&rs->buf, &rs->buf_size, 0) < 0
      || packet_ok (rs->buf, packet) != PACKET_OK)
    return -1;

  unpack_varlen_hex (rs->buf, &n);
  return n;
}

/* Read OBJECT_NAME/ANNEX from the remote target using a qXfer packet.
   Data at OFFSET, of up to LEN bytes, is read into READBUF; the
   number of bytes read is returned, or 0 for EOF, or -1 for error.
   The number of bytes read may be less than LEN without indicating an
   EOF.  PACKET is checked and updated to indicate whether the remote
   target supports this object.  */

static LONGEST
remote_read_qxfer (struct target_ops *ops, const char *object_name,
                   const char *annex,
                   gdb_byte *readbuf, ULONGEST offset, LONGEST len,
                   struct packet_config *packet)
{
  static char *finished_object;
  static char *finished_annex;
  static ULONGEST finished_offset;

  struct remote_state *rs = get_remote_state ();
  unsigned int total = 0;
  LONGEST i, n, packet_len;

  if (packet->support == PACKET_DISABLE)
    return -1;

  /* Check whether we've cached an end-of-object packet that matches
     this request.  */
  if (finished_object)
    {
      if (strcmp (object_name, finished_object) == 0
          && strcmp (annex ? annex : "", finished_annex) == 0
          && offset == finished_offset)
        return 0;

      /* Otherwise, we're now reading something different.  Discard
         the cache.  */
      xfree (finished_object);
      xfree (finished_annex);
      finished_object = NULL;
      finished_annex = NULL;
    }

  /* Request only enough to fit in a single packet.  The actual data
     may not, since we don't know how much of it will need to be escaped;
     the target is free to respond with slightly less data.  We subtract
     five to account for the response type and the protocol frame.  */
  n = min (get_remote_packet_size () - 5, len);
  snprintf (rs->buf, get_remote_packet_size () - 4, "qXfer:%s:read:%s:%s,%s",
            object_name, annex ? annex : "",
            phex_nz (offset, sizeof offset),
            phex_nz (n, sizeof n));
  i = putpkt (rs->buf);
  if (i < 0)
    return -1;

  rs->buf[0] = '\0';
  packet_len = getpkt_sane (&rs->buf, &rs->buf_size, 0);
  if (packet_len < 0 || packet_ok (rs->buf, packet) != PACKET_OK)
    return -1;

  if (rs->buf[0] != 'l' && rs->buf[0] != 'm')
    error (_("Unknown remote qXfer reply: %s"), rs->buf);

  /* 'm' means there is (or at least might be) more data after this
     batch.  That does not make sense unless there's at least one byte
     of data in this reply.  */
  if (rs->buf[0] == 'm' && packet_len == 1)
    error (_("Remote qXfer reply contained no data."));

  /* Got some data.  */
  i = remote_unescape_input (rs->buf + 1, packet_len - 1, readbuf, n);

  /* 'l' is an EOF marker, possibly including a final block of data,
     or possibly empty.  If we have the final block of a non-empty
     object, record this fact to bypass a subsequent partial read.  */
  if (rs->buf[0] == 'l' && offset + i > 0)
    {
      finished_object = xstrdup (object_name);
      finished_annex = xstrdup (annex ? annex : "");
      finished_offset = offset + i;
    }

  return i;
}

static LONGEST
remote_xfer_partial (struct target_ops *ops, enum target_object object,
                     const char *annex, gdb_byte *readbuf,
                     const gdb_byte *writebuf, ULONGEST offset, LONGEST len)
{
  struct remote_state *rs;
  int i;
  char *p2;
  char query_type;

  set_general_thread (inferior_ptid);

  rs = get_remote_state ();

  /* Handle memory using the standard memory routines.  */
  if (object == TARGET_OBJECT_MEMORY)
    {
      int xfered;
      errno = 0;

      /* If the remote target is connected but not running, we should
         pass this request down to a lower stratum (e.g. the executable
         file).  */
      if (!target_has_execution)
        return 0;

      if (writebuf != NULL)
        xfered = remote_write_bytes (offset, writebuf, len);
      else
        xfered = remote_read_bytes (offset, readbuf, len);

      if (xfered > 0)
        return xfered;
      else if (xfered == 0 && errno == 0)
        return 0;
      else
        return -1;
    }

  /* Handle SPU memory using qxfer packets. */
  if (object == TARGET_OBJECT_SPU)
    {
      if (readbuf)
        return remote_read_qxfer (ops, "spu", annex, readbuf, offset, len,
                                  &remote_protocol_packets
                                    [PACKET_qXfer_spu_read]);
      else
        return remote_write_qxfer (ops, "spu", annex, writebuf, offset, len,
                                   &remote_protocol_packets
                                     [PACKET_qXfer_spu_write]);
    }

  /* Only handle flash writes.  */
  if (writebuf != NULL)
    {
      LONGEST xfered;

      switch (object)
        {
        case TARGET_OBJECT_FLASH:
          xfered = remote_flash_write (ops, offset, len, writebuf);

          if (xfered > 0)
            return xfered;
          else if (xfered == 0 && errno == 0)
            return 0;
          else
            return -1;

        default:
          return -1;
        }
    }

  /* Map pre-existing objects onto letters.  DO NOT do this for new
     objects!!!  Instead specify new query packets.  */
  switch (object)
    {
    case TARGET_OBJECT_AVR:
      query_type = 'R';
      break;

    case TARGET_OBJECT_AUXV:
      gdb_assert (annex == NULL);
      return remote_read_qxfer (ops, "auxv", annex, readbuf, offset, len,
                                &remote_protocol_packets[PACKET_qXfer_auxv]);

    case TARGET_OBJECT_AVAILABLE_FEATURES:
      return remote_read_qxfer
        (ops, "features", annex, readbuf, offset, len,
         &remote_protocol_packets[PACKET_qXfer_features]);

    case TARGET_OBJECT_LIBRARIES:
      return remote_read_qxfer
        (ops, "libraries", annex, readbuf, offset, len,
         &remote_protocol_packets[PACKET_qXfer_libraries]);

    case TARGET_OBJECT_MEMORY_MAP:
      gdb_assert (annex == NULL);
      return remote_read_qxfer (ops, "memory-map", annex, readbuf, offset, len,
                                &remote_protocol_packets[PACKET_qXfer_memory_map]);

    default:
      return -1;
    }

  /* Note: a zero OFFSET and LEN can be used to query the minimum
     buffer size.  */
  if (offset == 0 && len == 0)
    return (get_remote_packet_size ());
  /* Minimum outbuf size is get_remote_packet_size (). If LEN is not
     large enough let the caller deal with it.  */
  if (len < get_remote_packet_size ())
    return -1;
  len = get_remote_packet_size ();

  /* Except for querying the minimum buffer size, target must be open.  */
  if (!remote_desc)
    error (_("remote query is only available after target open"));

  gdb_assert (annex != NULL);
  gdb_assert (readbuf != NULL);

  p2 = rs->buf;
  *p2++ = 'q';
  *p2++ = query_type;

  /* We used one buffer char for the remote protocol q command and
     another for the query type.  As the remote protocol encapsulation
     uses 4 chars plus one extra in case we are debugging
     (remote_debug), we have PBUFZIZ - 7 left to pack the query
     string.  */
  i = 0;
  while (annex[i] && (i < (get_remote_packet_size () - 8)))
    {
      /* Bad caller may have sent forbidden characters.  */
      gdb_assert (isprint (annex[i]) && annex[i] != '$' && annex[i] != '#');
      *p2++ = annex[i];
      i++;
    }
  *p2 = '\0';
  gdb_assert (annex[i] == '\0');

  i = putpkt (rs->buf);
  if (i < 0)
    return i;

  getpkt (&rs->buf, &rs->buf_size, 0);
  strcpy ((char *) readbuf, rs->buf);

  return strlen ((char *) readbuf);
}

static int
remote_search_memory (struct target_ops* ops,
                      CORE_ADDR start_addr, ULONGEST search_space_len,
                      const gdb_byte *pattern, ULONGEST pattern_len,
                      CORE_ADDR *found_addrp)
{
  struct remote_state *rs = get_remote_state ();
  int max_size = get_memory_write_packet_size ();
  struct packet_config *packet =
    &remote_protocol_packets[PACKET_qSearch_memory];
  /* number of packet bytes used to encode the pattern,
     this could be more than PATTERN_LEN due to escape characters */
  int escaped_pattern_len;
  /* amount of pattern that was encodable in the packet */
  int used_pattern_len;
  int i;
  int found;
  ULONGEST found_addr;

  /* Don't go to the target if we don't have to.
     This is done before checking packet->support to avoid the possibility that
     a success for this edge case means the facility works in general.  */
  if (pattern_len > search_space_len)
    return 0;
  if (pattern_len == 0)
    {
      *found_addrp = start_addr;
      return 1;
    }

  /* If we already know the packet isn't supported, fall back to the simple
     way of searching memory.  */

  if (packet->support == PACKET_DISABLE)
    {
      /* Target doesn't provided special support, fall back and use the
         standard support (copy memory and do the search here).  */
      return simple_search_memory (ops, start_addr, search_space_len,
                                   pattern, pattern_len, found_addrp);
    }

  /* Insert header.  */
  i = snprintf (rs->buf, max_size, 
                "qSearch:memory:%s;%s;",
                paddr_nz (start_addr),
                phex_nz (search_space_len, sizeof (search_space_len)));
  max_size -= (i + 1);

  /* Escape as much data as fits into rs->buf.  */
  escaped_pattern_len =
    remote_escape_output (pattern, pattern_len, (rs->buf + i),
                          &used_pattern_len, max_size);

  /* Bail if the pattern is too large.  */
  if (used_pattern_len != pattern_len)
    error ("Pattern is too large to transmit to remote target.");

  if (putpkt_binary (rs->buf, i + escaped_pattern_len) < 0
      || getpkt_sane (&rs->buf, &rs->buf_size, 0) < 0
      || packet_ok (rs->buf, packet) != PACKET_OK)
    {
      /* The request may not have worked because the command is not
         supported.  If so, fall back to the simple way.  */
      if (packet->support == PACKET_DISABLE)
        {
          return simple_search_memory (ops, start_addr, search_space_len,
                                       pattern, pattern_len, found_addrp);
        }
      return -1;
    }

  if (rs->buf[0] == '0')
    found = 0;
  else if (rs->buf[0] == '1')
    {
      found = 1;
      if (rs->buf[1] != ',')
        error (_("Unknown qSearch:memory reply: %s"), rs->buf);
      unpack_varlen_hex (rs->buf + 2, &found_addr);
      *found_addrp = found_addr;
    }
  else
    error (_("Unknown qSearch:memory reply: %s"), rs->buf);

  return found;
}

static void
remote_rcmd (char *command,
             struct ui_file *outbuf)
{
  struct remote_state *rs = get_remote_state ();
  char *p = rs->buf;

  if (!remote_desc)
    error (_("remote rcmd is only available after target open"));

  /* Send a NULL command across as an empty command.  */
  if (command == NULL)
    command = "";

  /* The query prefix.  */
  strcpy (rs->buf, "qRcmd,");
  p = strchr (rs->buf, '\0');

  if ((strlen (rs->buf) + strlen (command) * 2 + 8/*misc*/) > get_remote_packet_size ())
    error (_("\"monitor\" command ``%s'' is too long."), command);

  /* Encode the actual command.  */
  bin2hex ((gdb_byte *) command, p, 0);

  if (putpkt (rs->buf) < 0)
    error (_("Communication problem with target."));

  /* get/display the response */
  while (1)
    {
      char *buf;

      /* XXX - see also tracepoint.c:remote_get_noisy_reply().  */
      rs->buf[0] = '\0';
      getpkt (&rs->buf, &rs->buf_size, 0);
      buf = rs->buf;
      if (buf[0] == '\0')
        error (_("Target does not support this command."));
      if (buf[0] == 'O' && buf[1] != 'K')
        {
          remote_console_output (buf + 1); /* 'O' message from stub.  */
          continue;
        }
      if (strcmp (buf, "OK") == 0)
        break;
      if (strlen (buf) == 3 && buf[0] == 'E'
          && isdigit (buf[1]) && isdigit (buf[2]))
        {
          error (_("Protocol error with Rcmd"));
        }
      for (p = buf; p[0] != '\0' && p[1] != '\0'; p += 2)
        {
          char c = (fromhex (p[0]) << 4) + fromhex (p[1]);
          fputc_unfiltered (c, outbuf);
        }
      break;
    }
}

static VEC(mem_region_s) *
remote_memory_map (struct target_ops *ops)
{
  VEC(mem_region_s) *result = NULL;
  char *text = target_read_stralloc (&current_target,
                                     TARGET_OBJECT_MEMORY_MAP, NULL);

  if (text)
    {
      struct cleanup *back_to = make_cleanup (xfree, text);
      result = parse_memory_map (text);
      do_cleanups (back_to);
    }

  return result;
}

static void
packet_command (char *args, int from_tty)
{
  struct remote_state *rs = get_remote_state ();

  if (!remote_desc)
    error (_("command can only be used with remote target"));

  if (!args)
    error (_("remote-packet command requires packet text as argument"));

  puts_filtered ("sending: ");
  print_packet (args);
  puts_filtered ("\n");
  putpkt (args);

  getpkt (&rs->buf, &rs->buf_size, 0);
  puts_filtered ("received: ");
  print_packet (rs->buf);
  puts_filtered ("\n");
}

#if 0
/* --------- UNIT_TEST for THREAD oriented PACKETS ------------------- */

static void display_thread_info (struct gdb_ext_thread_info *info);

static void threadset_test_cmd (char *cmd, int tty);

static void threadalive_test (char *cmd, int tty);

static void threadlist_test_cmd (char *cmd, int tty);

int get_and_display_threadinfo (threadref *ref);

static void threadinfo_test_cmd (char *cmd, int tty);

static int thread_display_step (threadref *ref, void *context);

static void threadlist_update_test_cmd (char *cmd, int tty);

static void init_remote_threadtests (void);

#define SAMPLE_THREAD  0x05060708       /* Truncated 64 bit threadid.  */

static void
threadset_test_cmd (char *cmd, int tty)
{
  int sample_thread = SAMPLE_THREAD;

  printf_filtered (_("Remote threadset test\n"));
  set_general_thread (sample_thread);
}


static void
threadalive_test (char *cmd, int tty)
{
  int sample_thread = SAMPLE_THREAD;
  int pid = ptid_get_pid (inferior_ptid);
  ptid_t ptid = ptid_build (pid, 0, sample_thread);

  if (remote_thread_alive (ptid))
    printf_filtered ("PASS: Thread alive test\n");
  else
    printf_filtered ("FAIL: Thread alive test\n");
}

void output_threadid (char *title, threadref *ref);

void
output_threadid (char *title, threadref *ref)
{
  char hexid[20];

  pack_threadid (&hexid[0], ref);       /* Convert threead id into hex.  */
  hexid[16] = 0;
  printf_filtered ("%s  %s\n", title, (&hexid[0]));
}

static void
threadlist_test_cmd (char *cmd, int tty)
{
  int startflag = 1;
  threadref nextthread;
  int done, result_count;
  threadref threadlist[3];

  printf_filtered ("Remote Threadlist test\n");
  if (!remote_get_threadlist (startflag, &nextthread, 3, &done,
                              &result_count, &threadlist[0]))
    printf_filtered ("FAIL: threadlist test\n");
  else
    {
      threadref *scan = threadlist;
      threadref *limit = scan + result_count;

      while (scan < limit)
        output_threadid (" thread ", scan++);
    }
}

void
display_thread_info (struct gdb_ext_thread_info *info)
{
  output_threadid ("Threadid: ", &info->threadid);
  printf_filtered ("Name: %s\n ", info->shortname);
  printf_filtered ("State: %s\n", info->display);
  printf_filtered ("other: %s\n\n", info->more_display);
}

int
get_and_display_threadinfo (threadref *ref)
{
  int result;
  int set;
  struct gdb_ext_thread_info threadinfo;

  set = TAG_THREADID | TAG_EXISTS | TAG_THREADNAME
    | TAG_MOREDISPLAY | TAG_DISPLAY;
  if (0 != (result = remote_get_threadinfo (ref, set, &threadinfo)))
    display_thread_info (&threadinfo);
  return result;
}

static void
threadinfo_test_cmd (char *cmd, int tty)
{
  int athread = SAMPLE_THREAD;
  threadref thread;
  int set;

  int_to_threadref (&thread, athread);
  printf_filtered ("Remote Threadinfo test\n");
  if (!get_and_display_threadinfo (&thread))
    printf_filtered ("FAIL cannot get thread info\n");
}

static int
thread_display_step (threadref *ref, void *context)
{
  /* output_threadid(" threadstep ",ref); *//* simple test */
  return get_and_display_threadinfo (ref);
}

static void
threadlist_update_test_cmd (char *cmd, int tty)
{
  printf_filtered ("Remote Threadlist update test\n");
  remote_threadlist_iterator (thread_display_step, 0, CRAZY_MAX_THREADS);
}

static void
init_remote_threadtests (void)
{
  add_com ("tlist", class_obscure, threadlist_test_cmd, _("\
Fetch and print the remote list of thread identifiers, one pkt only"));
  add_com ("tinfo", class_obscure, threadinfo_test_cmd,
           _("Fetch and display info about one thread"));
  add_com ("tset", class_obscure, threadset_test_cmd,
           _("Test setting to a different thread"));
  add_com ("tupd", class_obscure, threadlist_update_test_cmd,
           _("Iterate through updating all remote thread info"));
  add_com ("talive", class_obscure, threadalive_test,
           _(" Remote thread alive test "));
}

#endif /* 0 */

/* Convert a thread ID to a string.  Returns the string in a static
   buffer.  */

static char *
remote_pid_to_str (ptid_t ptid)
{
  static char buf[64];
  struct remote_state *rs = get_remote_state ();

  if (ptid_equal (magic_null_ptid, ptid))
    {
      xsnprintf (buf, sizeof buf, "Thread <main>");
      return buf;
    }
  else if (remote_multi_process_p (rs)
           && ptid_get_tid (ptid) != 0 && ptid_get_pid (ptid) != 0)
    {
      xsnprintf (buf, sizeof buf, "Thread %d.%ld",
                 ptid_get_pid (ptid), ptid_get_tid (ptid));
      return buf;
    }
  else if (ptid_get_tid (ptid) != 0)
    {
      xsnprintf (buf, sizeof buf, "Thread %ld",
                 ptid_get_tid (ptid));
      return buf;
    }

  return normal_pid_to_str (ptid);
}

/* Get the address of the thread local variable in OBJFILE which is
   stored at OFFSET within the thread local storage for thread PTID.  */

static CORE_ADDR
remote_get_thread_local_address (ptid_t ptid, CORE_ADDR lm, CORE_ADDR offset)
{
  if (remote_protocol_packets[PACKET_qGetTLSAddr].support != PACKET_DISABLE)
    {
      struct remote_state *rs = get_remote_state ();
      char *p = rs->buf;
      char *endp = rs->buf + get_remote_packet_size ();
      enum packet_result result;

      strcpy (p, "qGetTLSAddr:");
      p += strlen (p);
      p = write_ptid (p, endp, ptid);
      *p++ = ',';
      p += hexnumstr (p, offset);
      *p++ = ',';
      p += hexnumstr (p, lm);
      *p++ = '\0';

      putpkt (rs->buf);
      getpkt (&rs->buf, &rs->buf_size, 0);
      result = packet_ok (rs->buf, &remote_protocol_packets[PACKET_qGetTLSAddr]);
      if (result == PACKET_OK)
        {
          ULONGEST result;

          unpack_varlen_hex (rs->buf, &result);
          return result;
        }
      else if (result == PACKET_UNKNOWN)
        throw_error (TLS_GENERIC_ERROR,
                     _("Remote target doesn't support qGetTLSAddr packet"));
      else
        throw_error (TLS_GENERIC_ERROR,
                     _("Remote target failed to process qGetTLSAddr request"));
    }
  else
    throw_error (TLS_GENERIC_ERROR,
                 _("TLS not supported or disabled on this target"));
  /* Not reached.  */
  return 0;
}

/* Support for inferring a target description based on the current
   architecture and the size of a 'g' packet.  While the 'g' packet
   can have any size (since optional registers can be left off the
   end), some sizes are easily recognizable given knowledge of the
   approximate architecture.  */

struct remote_g_packet_guess
{
  int bytes;
  const struct target_desc *tdesc;
};
typedef struct remote_g_packet_guess remote_g_packet_guess_s;
DEF_VEC_O(remote_g_packet_guess_s);

struct remote_g_packet_data
{
  VEC(remote_g_packet_guess_s) *guesses;
};

static struct gdbarch_data *remote_g_packet_data_handle;

static void *
remote_g_packet_data_init (struct obstack *obstack)
{
  return OBSTACK_ZALLOC (obstack, struct remote_g_packet_data);
}

void
register_remote_g_packet_guess (struct gdbarch *gdbarch, int bytes,
                                const struct target_desc *tdesc)
{
  struct remote_g_packet_data *data
    = gdbarch_data (gdbarch, remote_g_packet_data_handle);
  struct remote_g_packet_guess new_guess, *guess;
  int ix;

  gdb_assert (tdesc != NULL);

  for (ix = 0;
       VEC_iterate (remote_g_packet_guess_s, data->guesses, ix, guess);
       ix++)
    if (guess->bytes == bytes)
      internal_error (__FILE__, __LINE__,
                      "Duplicate g packet description added for size %d",
                      bytes);

  new_guess.bytes = bytes;
  new_guess.tdesc = tdesc;
  VEC_safe_push (remote_g_packet_guess_s, data->guesses, &new_guess);
}

static const struct target_desc *
remote_read_description (struct target_ops *target)
{
  struct remote_g_packet_data *data
    = gdbarch_data (target_gdbarch, remote_g_packet_data_handle);

  if (!VEC_empty (remote_g_packet_guess_s, data->guesses))
    {
      struct remote_g_packet_guess *guess;
      int ix;
      int bytes = send_g_packet ();

      for (ix = 0;
           VEC_iterate (remote_g_packet_guess_s, data->guesses, ix, guess);
           ix++)
        if (guess->bytes == bytes)
          return guess->tdesc;

      /* We discard the g packet.  A minor optimization would be to
         hold on to it, and fill the register cache once we have selected
         an architecture, but it's too tricky to do safely.  */
    }

  return NULL;
}

/* Remote file transfer support.  This is host-initiated I/O, not
   target-initiated; for target-initiated, see remote-fileio.c.  */

/* If *LEFT is at least the length of STRING, copy STRING to
   *BUFFER, update *BUFFER to point to the new end of the buffer, and
   decrease *LEFT.  Otherwise raise an error.  */

static void
remote_buffer_add_string (char **buffer, int *left, char *string)
{
  int len = strlen (string);

  if (len > *left)
    error (_("Packet too long for target."));

  memcpy (*buffer, string, len);
  *buffer += len;
  *left -= len;

  /* NUL-terminate the buffer as a convenience, if there is
     room.  */
  if (*left)
    **buffer = '\0';
}

/* If *LEFT is large enough, hex encode LEN bytes from BYTES into
   *BUFFER, update *BUFFER to point to the new end of the buffer, and
   decrease *LEFT.  Otherwise raise an error.  */

static void
remote_buffer_add_bytes (char **buffer, int *left, const gdb_byte *bytes,
                         int len)
{
  if (2 * len > *left)
    error (_("Packet too long for target."));

  bin2hex (bytes, *buffer, len);
  *buffer += 2 * len;
  *left -= 2 * len;

  /* NUL-terminate the buffer as a convenience, if there is
     room.  */
  if (*left)
    **buffer = '\0';
}

/* If *LEFT is large enough, convert VALUE to hex and add it to
   *BUFFER, update *BUFFER to point to the new end of the buffer, and
   decrease *LEFT.  Otherwise raise an error.  */

static void
remote_buffer_add_int (char **buffer, int *left, ULONGEST value)
{
  int len = hexnumlen (value);

  if (len > *left)
    error (_("Packet too long for target."));

  hexnumstr (*buffer, value);
  *buffer += len;
  *left -= len;

  /* NUL-terminate the buffer as a convenience, if there is
     room.  */
  if (*left)
    **buffer = '\0';
}

/* Parse an I/O result packet from BUFFER.  Set RETCODE to the return
   value, *REMOTE_ERRNO to the remote error number or zero if none
   was included, and *ATTACHMENT to point to the start of the annex
   if any.  The length of the packet isn't needed here; there may
   be NUL bytes in BUFFER, but they will be after *ATTACHMENT.

   Return 0 if the packet could be parsed, -1 if it could not.  If
   -1 is returned, the other variables may not be initialized.  */

static int
remote_hostio_parse_result (char *buffer, int *retcode,
                            int *remote_errno, char **attachment)
{
  char *p, *p2;

  *remote_errno = 0;
  *attachment = NULL;

  if (buffer[0] != 'F')
    return -1;

  errno = 0;
  *retcode = strtol (&buffer[1], &p, 16);
  if (errno != 0 || p == &buffer[1])
    return -1;

  /* Check for ",errno".  */
  if (*p == ',')
    {
      errno = 0;
      *remote_errno = strtol (p + 1, &p2, 16);
      if (errno != 0 || p + 1 == p2)
        return -1;
      p = p2;
    }

  /* Check for ";attachment".  If there is no attachment, the
     packet should end here.  */
  if (*p == ';')
    {
      *attachment = p + 1;
      return 0;
    }
  else if (*p == '\0')
    return 0;
  else
    return -1;
}

/* Send a prepared I/O packet to the target and read its response.
   The prepared packet is in the global RS->BUF before this function
   is called, and the answer is there when we return.

   COMMAND_BYTES is the length of the request to send, which may include
   binary data.  WHICH_PACKET is the packet configuration to check
   before attempting a packet.  If an error occurs, *REMOTE_ERRNO
   is set to the error number and -1 is returned.  Otherwise the value
   returned by the function is returned.

   ATTACHMENT and ATTACHMENT_LEN should be non-NULL if and only if an
   attachment is expected; an error will be reported if there's a
   mismatch.  If one is found, *ATTACHMENT will be set to point into
   the packet buffer and *ATTACHMENT_LEN will be set to the
   attachment's length.  */

static int
remote_hostio_send_command (int command_bytes, int which_packet,
                            int *remote_errno, char **attachment,
                            int *attachment_len)
{
  struct remote_state *rs = get_remote_state ();
  int ret, bytes_read;
  char *attachment_tmp;

  if (!remote_desc
      || remote_protocol_packets[which_packet].support == PACKET_DISABLE)
    {
      *remote_errno = FILEIO_ENOSYS;
      return -1;
    }

  putpkt_binary (rs->buf, command_bytes);
  bytes_read = getpkt_sane (&rs->buf, &rs->buf_size, 0);

  /* If it timed out, something is wrong.  Don't try to parse the
     buffer.  */
  if (bytes_read < 0)
    {
      *remote_errno = FILEIO_EINVAL;
      return -1;
    }

  switch (packet_ok (rs->buf, &remote_protocol_packets[which_packet]))
    {
    case PACKET_ERROR:
      *remote_errno = FILEIO_EINVAL;
      return -1;
    case PACKET_UNKNOWN:
      *remote_errno = FILEIO_ENOSYS;
      return -1;
    case PACKET_OK:
      break;
    }

  if (remote_hostio_parse_result (rs->buf, &ret, remote_errno,
                                  &attachment_tmp))
    {
      *remote_errno = FILEIO_EINVAL;
      return -1;
    }

  /* Make sure we saw an attachment if and only if we expected one.  */
  if ((attachment_tmp == NULL && attachment != NULL)
      || (attachment_tmp != NULL && attachment == NULL))
    {
      *remote_errno = FILEIO_EINVAL;
      return -1;
    }

  /* If an attachment was found, it must point into the packet buffer;
     work out how many bytes there were.  */
  if (attachment_tmp != NULL)
    {
      *attachment = attachment_tmp;
      *attachment_len = bytes_read - (*attachment - rs->buf);
    }

  return ret;
}

/* Open FILENAME on the remote target, using FLAGS and MODE.  Return a
   remote file descriptor, or -1 if an error occurs (and set
   *REMOTE_ERRNO).  */

static int
remote_hostio_open (const char *filename, int flags, int mode,
                    int *remote_errno)
{
  struct remote_state *rs = get_remote_state ();
  char *p = rs->buf;
  int left = get_remote_packet_size () - 1;

  remote_buffer_add_string (&p, &left, "vFile:open:");

  remote_buffer_add_bytes (&p, &left, (const gdb_byte *) filename,
                           strlen (filename));
  remote_buffer_add_string (&p, &left, ",");

  remote_buffer_add_int (&p, &left, flags);
  remote_buffer_add_string (&p, &left, ",");

  remote_buffer_add_int (&p, &left, mode);

  return remote_hostio_send_command (p - rs->buf, PACKET_vFile_open,
                                     remote_errno, NULL, NULL);
}

/* Write up to LEN bytes from WRITE_BUF to FD on the remote target.
   Return the number of bytes written, or -1 if an error occurs (and
   set *REMOTE_ERRNO).  */

static int
remote_hostio_pwrite (int fd, const gdb_byte *write_buf, int len,
                      ULONGEST offset, int *remote_errno)
{
  struct remote_state *rs = get_remote_state ();
  char *p = rs->buf;
  int left = get_remote_packet_size ();
  int out_len;

  remote_buffer_add_string (&p, &left, "vFile:pwrite:");

  remote_buffer_add_int (&p, &left, fd);
  remote_buffer_add_string (&p, &left, ",");

  remote_buffer_add_int (&p, &left, offset);
  remote_buffer_add_string (&p, &left, ",");

  p += remote_escape_output (write_buf, len, p, &out_len,
                             get_remote_packet_size () - (p - rs->buf));

  return remote_hostio_send_command (p - rs->buf, PACKET_vFile_pwrite,
                                     remote_errno, NULL, NULL);
}

/* Read up to LEN bytes FD on the remote target into READ_BUF
   Return the number of bytes read, or -1 if an error occurs (and
   set *REMOTE_ERRNO).  */

static int
remote_hostio_pread (int fd, gdb_byte *read_buf, int len,
                     ULONGEST offset, int *remote_errno)
{
  struct remote_state *rs = get_remote_state ();
  char *p = rs->buf;
  char *attachment;
  int left = get_remote_packet_size ();
  int ret, attachment_len;
  int read_len;

  remote_buffer_add_string (&p, &left, "vFile:pread:");

  remote_buffer_add_int (&p, &left, fd);
  remote_buffer_add_string (&p, &left, ",");

  remote_buffer_add_int (&p, &left, len);
  remote_buffer_add_string (&p, &left, ",");

  remote_buffer_add_int (&p, &left, offset);

  ret = remote_hostio_send_command (p - rs->buf, PACKET_vFile_pread,
                                    remote_errno, &attachment,
                                    &attachment_len);

  if (ret < 0)
    return ret;

  read_len = remote_unescape_input (attachment, attachment_len,
                                    read_buf, len);
  if (read_len != ret)
    error (_("Read returned %d, but %d bytes."), ret, (int) read_len);

  return ret;
}

/* Close FD on the remote target.  Return 0, or -1 if an error occurs
   (and set *REMOTE_ERRNO).  */

static int
remote_hostio_close (int fd, int *remote_errno)
{
  struct remote_state *rs = get_remote_state ();
  char *p = rs->buf;
  int left = get_remote_packet_size () - 1;

  remote_buffer_add_string (&p, &left, "vFile:close:");

  remote_buffer_add_int (&p, &left, fd);

  return remote_hostio_send_command (p - rs->buf, PACKET_vFile_close,
                                     remote_errno, NULL, NULL);
}

/* Unlink FILENAME on the remote target.  Return 0, or -1 if an error
   occurs (and set *REMOTE_ERRNO).  */

static int
remote_hostio_unlink (const char *filename, int *remote_errno)
{
  struct remote_state *rs = get_remote_state ();
  char *p = rs->buf;
  int left = get_remote_packet_size () - 1;

  remote_buffer_add_string (&p, &left, "vFile:unlink:");

  remote_buffer_add_bytes (&p, &left, (const gdb_byte *) filename,
                           strlen (filename));

  return remote_hostio_send_command (p - rs->buf, PACKET_vFile_unlink,
                                     remote_errno, NULL, NULL);
}

static int
remote_fileio_errno_to_host (int errnum)
{
  switch (errnum)
    {
      case FILEIO_EPERM:
        return EPERM;
      case FILEIO_ENOENT:
        return ENOENT;
      case FILEIO_EINTR:
        return EINTR;
      case FILEIO_EIO:
        return EIO;
      case FILEIO_EBADF:
        return EBADF;
      case FILEIO_EACCES:
        return EACCES;
      case FILEIO_EFAULT:
        return EFAULT;
      case FILEIO_EBUSY:
        return EBUSY;
      case FILEIO_EEXIST:
        return EEXIST;
      case FILEIO_ENODEV:
        return ENODEV;
      case FILEIO_ENOTDIR:
        return ENOTDIR;
      case FILEIO_EISDIR:
        return EISDIR;
      case FILEIO_EINVAL:
        return EINVAL;
      case FILEIO_ENFILE:
        return ENFILE;
      case FILEIO_EMFILE:
        return EMFILE;
      case FILEIO_EFBIG:
        return EFBIG;
      case FILEIO_ENOSPC:
        return ENOSPC;
      case FILEIO_ESPIPE:
        return ESPIPE;
      case FILEIO_EROFS:
        return EROFS;
      case FILEIO_ENOSYS:
        return ENOSYS;
      case FILEIO_ENAMETOOLONG:
        return ENAMETOOLONG;
    }
  return -1;
}

static char *
remote_hostio_error (int errnum)
{
  int host_error = remote_fileio_errno_to_host (errnum);

  if (host_error == -1)
    error (_("Unknown remote I/O error %d"), errnum);
  else
    error (_("Remote I/O error: %s"), safe_strerror (host_error));
}

static void
remote_hostio_close_cleanup (void *opaque)
{
  int fd = *(int *) opaque;
  int remote_errno;

  remote_hostio_close (fd, &remote_errno);
}


static void *
remote_bfd_iovec_open (struct bfd *abfd, void *open_closure)
{
  const char *filename = bfd_get_filename (abfd);
  int fd, remote_errno;
  int *stream;

  gdb_assert (remote_filename_p (filename));

  fd = remote_hostio_open (filename + 7, FILEIO_O_RDONLY, 0, &remote_errno);
  if (fd == -1)
    {
      errno = remote_fileio_errno_to_host (remote_errno);
      bfd_set_error (bfd_error_system_call);
      return NULL;
    }

  stream = xmalloc (sizeof (int));
  *stream = fd;
  return stream;
}

static int
remote_bfd_iovec_close (struct bfd *abfd, void *stream)
{
  int fd = *(int *)stream;
  int remote_errno;

  xfree (stream);

  /* Ignore errors on close; these may happen if the remote
     connection was already torn down.  */
  remote_hostio_close (fd, &remote_errno);

  return 1;
}

static file_ptr
remote_bfd_iovec_pread (struct bfd *abfd, void *stream, void *buf,
                        file_ptr nbytes, file_ptr offset)
{
  int fd = *(int *)stream;
  int remote_errno;
  file_ptr pos, bytes;

  pos = 0;
  while (nbytes > pos)
    {
      bytes = remote_hostio_pread (fd, (char *)buf + pos, nbytes - pos,
                                   offset + pos, &remote_errno);
      if (bytes == 0)
        /* Success, but no bytes, means end-of-file.  */
        break;
      if (bytes == -1)
        {
          errno = remote_fileio_errno_to_host (remote_errno);
          bfd_set_error (bfd_error_system_call);
          return -1;
        }

      pos += bytes;
    }

  return pos;
}

static int
remote_bfd_iovec_stat (struct bfd *abfd, void *stream, struct stat *sb)
{
  /* FIXME: We should probably implement remote_hostio_stat.  */
  sb->st_size = INT_MAX;
  return 0;
}

int
remote_filename_p (const char *filename)
{
  return strncmp (filename, "remote:", 7) == 0;
}

bfd *
remote_bfd_open (const char *remote_file, const char *target)
{
  return bfd_openr_iovec (remote_file, target,
                          remote_bfd_iovec_open, NULL,
                          remote_bfd_iovec_pread,
                          remote_bfd_iovec_close,
                          remote_bfd_iovec_stat);
}

void
remote_file_put (const char *local_file, const char *remote_file, int from_tty)
{
  struct cleanup *back_to, *close_cleanup;
  int retcode, fd, remote_errno, bytes, io_size;
  FILE *file;
  gdb_byte *buffer;
  int bytes_in_buffer;
  int saw_eof;
  ULONGEST offset;

  if (!remote_desc)
    error (_("command can only be used with remote target"));

  file = fopen (local_file, "rb");
  if (file == NULL)
    perror_with_name (local_file);
  back_to = make_cleanup_fclose (file);

  fd = remote_hostio_open (remote_file, (FILEIO_O_WRONLY | FILEIO_O_CREAT
                                         | FILEIO_O_TRUNC),
                           0700, &remote_errno);
  if (fd == -1)
    remote_hostio_error (remote_errno);

  /* Send up to this many bytes at once.  They won't all fit in the
     remote packet limit, so we'll transfer slightly fewer.  */
  io_size = get_remote_packet_size ();
  buffer = xmalloc (io_size);
  make_cleanup (xfree, buffer);

  close_cleanup = make_cleanup (remote_hostio_close_cleanup, &fd);

  bytes_in_buffer = 0;
  saw_eof = 0;
  offset = 0;
  while (bytes_in_buffer || !saw_eof)
    {
      if (!saw_eof)
        {
          bytes = fread (buffer + bytes_in_buffer, 1, io_size - bytes_in_buffer,
                         file);
          if (bytes == 0)
            {
              if (ferror (file))
                error (_("Error reading %s."), local_file);
              else
                {
                  /* EOF.  Unless there is something still in the
                     buffer from the last iteration, we are done.  */
                  saw_eof = 1;
                  if (bytes_in_buffer == 0)
                    break;
                }
            }
        }
      else
        bytes = 0;

      bytes += bytes_in_buffer;
      bytes_in_buffer = 0;

      retcode = remote_hostio_pwrite (fd, buffer, bytes, offset, &remote_errno);

      if (retcode < 0)
        remote_hostio_error (remote_errno);
      else if (retcode == 0)
        error (_("Remote write of %d bytes returned 0!"), bytes);
      else if (retcode < bytes)
        {
          /* Short write.  Save the rest of the read data for the next
             write.  */
          bytes_in_buffer = bytes - retcode;
          memmove (buffer, buffer + retcode, bytes_in_buffer);
        }

      offset += retcode;
    }

  discard_cleanups (close_cleanup);
  if (remote_hostio_close (fd, &remote_errno))
    remote_hostio_error (remote_errno);

  if (from_tty)
    printf_filtered (_("Successfully sent file \"%s\".\n"), local_file);
  do_cleanups (back_to);
}

void
remote_file_get (const char *remote_file, const char *local_file, int from_tty)
{
  struct cleanup *back_to, *close_cleanup;
  int retcode, fd, remote_errno, bytes, io_size;
  FILE *file;
  gdb_byte *buffer;
  ULONGEST offset;

  if (!remote_desc)
    error (_("command can only be used with remote target"));

  fd = remote_hostio_open (remote_file, FILEIO_O_RDONLY, 0, &remote_errno);
  if (fd == -1)
    remote_hostio_error (remote_errno);

  file = fopen (local_file, "wb");
  if (file == NULL)
    perror_with_name (local_file);
  back_to = make_cleanup_fclose (file);

  /* Send up to this many bytes at once.  They won't all fit in the
     remote packet limit, so we'll transfer slightly fewer.  */
  io_size = get_remote_packet_size ();
  buffer = xmalloc (io_size);
  make_cleanup (xfree, buffer);

  close_cleanup = make_cleanup (remote_hostio_close_cleanup, &fd);

  offset = 0;
  while (1)
    {
      bytes = remote_hostio_pread (fd, buffer, io_size, offset, &remote_errno);
      if (bytes == 0)
        /* Success, but no bytes, means end-of-file.  */
        break;
      if (bytes == -1)
        remote_hostio_error (remote_errno);

      offset += bytes;

      bytes = fwrite (buffer, 1, bytes, file);
      if (bytes == 0)
        perror_with_name (local_file);
    }

  discard_cleanups (close_cleanup);
  if (remote_hostio_close (fd, &remote_errno))
    remote_hostio_error (remote_errno);

  if (from_tty)
    printf_filtered (_("Successfully fetched file \"%s\".\n"), remote_file);
  do_cleanups (back_to);
}

void
remote_file_delete (const char *remote_file, int from_tty)
{
  int retcode, remote_errno;

  if (!remote_desc)
    error (_("command can only be used with remote target"));

  retcode = remote_hostio_unlink (remote_file, &remote_errno);
  if (retcode == -1)
    remote_hostio_error (remote_errno);

  if (from_tty)
    printf_filtered (_("Successfully deleted file \"%s\".\n"), remote_file);
}

static void
remote_put_command (char *args, int from_tty)
{
  struct cleanup *back_to;
  char **argv;

  if (args == NULL)
    error_no_arg (_("file to put"));

  argv = gdb_buildargv (args);
  back_to = make_cleanup_freeargv (argv);
  if (argv[0] == NULL || argv[1] == NULL || argv[2] != NULL)
    error (_("Invalid parameters to remote put"));

  remote_file_put (argv[0], argv[1], from_tty);

  do_cleanups (back_to);
}

static void
remote_get_command (char *args, int from_tty)
{
  struct cleanup *back_to;
  char **argv;

  if (args == NULL)
    error_no_arg (_("file to get"));

  argv = gdb_buildargv (args);
  back_to = make_cleanup_freeargv (argv);
  if (argv[0] == NULL || argv[1] == NULL || argv[2] != NULL)
    error (_("Invalid parameters to remote get"));

  remote_file_get (argv[0], argv[1], from_tty);

  do_cleanups (back_to);
}

static void
remote_delete_command (char *args, int from_tty)
{
  struct cleanup *back_to;
  char **argv;

  if (args == NULL)
    error_no_arg (_("file to delete"));

  argv = gdb_buildargv (args);
  back_to = make_cleanup_freeargv (argv);
  if (argv[0] == NULL || argv[1] != NULL)
    error (_("Invalid parameters to remote delete"));

  remote_file_delete (argv[0], from_tty);

  do_cleanups (back_to);
}

static void
remote_command (char *args, int from_tty)
{
  help_list (remote_cmdlist, "remote ", -1, gdb_stdout);
}

static int remote_target_can_reverse = 1;

static int
remote_can_execute_reverse (void)
{
  return remote_target_can_reverse;
}

static int
remote_supports_non_stop (void)
{
  return 1;
}

static int
remote_supports_multi_process (void)
{
  struct remote_state *rs = get_remote_state ();
  return remote_multi_process_p (rs);
}

static void
init_remote_ops (void)
{
  remote_ops.to_shortname = "remote";
  remote_ops.to_longname = "Remote serial target in gdb-specific protocol";
  remote_ops.to_doc =
    "Use a remote computer via a serial line, using a gdb-specific protocol.\n\
Specify the serial device it is connected to\n\
(e.g. /dev/ttyS0, /dev/ttya, COM1, etc.).";
  remote_ops.to_open = remote_open;
  remote_ops.to_close = remote_close;
  remote_ops.to_detach = remote_detach;
  remote_ops.to_disconnect = remote_disconnect;
  remote_ops.to_resume = remote_resume;
  remote_ops.to_wait = remote_wait;
  remote_ops.to_fetch_registers = remote_fetch_registers;
  remote_ops.to_store_registers = remote_store_registers;
  remote_ops.to_prepare_to_store = remote_prepare_to_store;
  remote_ops.deprecated_xfer_memory = remote_xfer_memory;
  remote_ops.to_files_info = remote_files_info;
  remote_ops.to_insert_breakpoint = remote_insert_breakpoint;
  remote_ops.to_remove_breakpoint = remote_remove_breakpoint;
  remote_ops.to_stopped_by_watchpoint = remote_stopped_by_watchpoint;
  remote_ops.to_stopped_data_address = remote_stopped_data_address;
  remote_ops.to_can_use_hw_breakpoint = remote_check_watch_resources;
  remote_ops.to_insert_hw_breakpoint = remote_insert_hw_breakpoint;
  remote_ops.to_remove_hw_breakpoint = remote_remove_hw_breakpoint;
  remote_ops.to_insert_watchpoint = remote_insert_watchpoint;
  remote_ops.to_remove_watchpoint = remote_remove_watchpoint;
  remote_ops.to_kill = remote_kill;
  remote_ops.to_load = generic_load;
  remote_ops.to_mourn_inferior = remote_mourn;
  remote_ops.to_thread_alive = remote_thread_alive;
  remote_ops.to_find_new_threads = remote_threads_info;
  remote_ops.to_pid_to_str = remote_pid_to_str;
  remote_ops.to_extra_thread_info = remote_threads_extra_info;
  remote_ops.to_stop = remote_stop;
  remote_ops.to_xfer_partial = remote_xfer_partial;
  remote_ops.to_rcmd = remote_rcmd;
  remote_ops.to_log_command = serial_log_command;
  remote_ops.to_get_thread_local_address = remote_get_thread_local_address;
  remote_ops.to_stratum = process_stratum;
  remote_ops.to_has_all_memory = 1;
  remote_ops.to_has_memory = 1;
  remote_ops.to_has_stack = 1;
  remote_ops.to_has_registers = 1;
  remote_ops.to_has_execution = 1;
  remote_ops.to_has_thread_control = tc_schedlock;      /* can lock scheduler */
  remote_ops.to_can_execute_reverse = remote_can_execute_reverse;
  remote_ops.to_magic = OPS_MAGIC;
  remote_ops.to_memory_map = remote_memory_map;
  remote_ops.to_flash_erase = remote_flash_erase;
  remote_ops.to_flash_done = remote_flash_done;
  remote_ops.to_read_description = remote_read_description;
  remote_ops.to_search_memory = remote_search_memory;
  remote_ops.to_can_async_p = remote_can_async_p;
  remote_ops.to_is_async_p = remote_is_async_p;
  remote_ops.to_async = remote_async;
  remote_ops.to_async_mask = remote_async_mask;
  remote_ops.to_terminal_inferior = remote_terminal_inferior;
  remote_ops.to_terminal_ours = remote_terminal_ours;
  remote_ops.to_supports_non_stop = remote_supports_non_stop;
  remote_ops.to_supports_multi_process = remote_supports_multi_process;
}

/* Set up the extended remote vector by making a copy of the standard
   remote vector and adding to it.  */

static void
init_extended_remote_ops (void)
{
  extended_remote_ops = remote_ops;

  extended_remote_ops.to_shortname = "extended-remote";
  extended_remote_ops.to_longname =
    "Extended remote serial target in gdb-specific protocol";
  extended_remote_ops.to_doc =
    "Use a remote computer via a serial line, using a gdb-specific protocol.\n\
Specify the serial device it is connected to (e.g. /dev/ttya).";
  extended_remote_ops.to_open = extended_remote_open;
  extended_remote_ops.to_create_inferior = extended_remote_create_inferior;
  extended_remote_ops.to_mourn_inferior = extended_remote_mourn;
  extended_remote_ops.to_detach = extended_remote_detach;
  extended_remote_ops.to_attach = extended_remote_attach;
  extended_remote_ops.to_kill = extended_remote_kill;
}

static int
remote_can_async_p (void)
{
  if (!target_async_permitted)
    /* We only enable async when the user specifically asks for it.  */
    return 0;

  /* We're async whenever the serial device is.  */
  return remote_async_mask_value && serial_can_async_p (remote_desc);
}

static int
remote_is_async_p (void)
{
  if (!target_async_permitted)
    /* We only enable async when the user specifically asks for it.  */
    return 0;

  /* We're async whenever the serial device is.  */
  return remote_async_mask_value && serial_is_async_p (remote_desc);
}

/* Pass the SERIAL event on and up to the client.  One day this code
   will be able to delay notifying the client of an event until the
   point where an entire packet has been received.  */

static void (*async_client_callback) (enum inferior_event_type event_type,
                                      void *context);
static void *async_client_context;
static serial_event_ftype remote_async_serial_handler;

static void
remote_async_serial_handler (struct serial *scb, void *context)
{
  /* Don't propogate error information up to the client.  Instead let
     the client find out about the error by querying the target.  */
  async_client_callback (INF_REG_EVENT, async_client_context);
}

static void
remote_async_inferior_event_handler (gdb_client_data data)
{
  inferior_event_handler (INF_REG_EVENT, NULL);
}

static void
remote_async_get_pending_events_handler (gdb_client_data data)
{
  remote_get_pending_stop_replies ();
}

static void
remote_async (void (*callback) (enum inferior_event_type event_type,
                                void *context), void *context)
{
  if (remote_async_mask_value == 0)
    internal_error (__FILE__, __LINE__,
                    _("Calling remote_async when async is masked"));

  if (callback != NULL)
    {
      serial_async (remote_desc, remote_async_serial_handler, NULL);
      async_client_callback = callback;
      async_client_context = context;
    }
  else
    serial_async (remote_desc, NULL, NULL);
}

static int
remote_async_mask (int new_mask)
{
  int curr_mask = remote_async_mask_value;
  remote_async_mask_value = new_mask;
  return curr_mask;
}

static void
set_remote_cmd (char *args, int from_tty)
{
  help_list (remote_set_cmdlist, "set remote ", -1, gdb_stdout);
}

static void
show_remote_cmd (char *args, int from_tty)
{
  /* We can't just use cmd_show_list here, because we want to skip
     the redundant "show remote Z-packet" and the legacy aliases.  */
  struct cleanup *showlist_chain;
  struct cmd_list_element *list = remote_show_cmdlist;

  showlist_chain = make_cleanup_ui_out_tuple_begin_end (uiout, "showlist");
  for (; list != NULL; list = list->next)
    if (strcmp (list->name, "Z-packet") == 0)
      continue;
    else if (list->type == not_set_cmd)
      /* Alias commands are exactly like the original, except they
         don't have the normal type.  */
      continue;
    else
      {
        struct cleanup *option_chain
          = make_cleanup_ui_out_tuple_begin_end (uiout, "option");
        ui_out_field_string (uiout, "name", list->name);
        ui_out_text (uiout, ":  ");
        if (list->type == show_cmd)
          do_setshow_command ((char *) NULL, from_tty, list);
        else
          cmd_func (list, NULL, from_tty);
        /* Close the tuple.  */
        do_cleanups (option_chain);
      }

  /* Close the tuple.  */
  do_cleanups (showlist_chain);
}


/* Function to be called whenever a new objfile (shlib) is detected.  */
static void
remote_new_objfile (struct objfile *objfile)
{
  if (remote_desc != 0)         /* Have a remote connection.  */
    remote_check_symbols (objfile);
}

void
_initialize_remote (void)
{
  struct remote_state *rs;

  /* architecture specific data */
  remote_gdbarch_data_handle =
    gdbarch_data_register_post_init (init_remote_state);
  remote_g_packet_data_handle =
    gdbarch_data_register_pre_init (remote_g_packet_data_init);

  /* Initialize the per-target state.  At the moment there is only one
     of these, not one per target.  Only one target is active at a
     time.  The default buffer size is unimportant; it will be expanded
     whenever a larger buffer is needed.  */
  rs = get_remote_state_raw ();
  rs->buf_size = 400;
  rs->buf = xmalloc (rs->buf_size);

  init_remote_ops ();
  add_target (&remote_ops);

  init_extended_remote_ops ();
  add_target (&extended_remote_ops);

  /* Hook into new objfile notification.  */
  observer_attach_new_objfile (remote_new_objfile);

  /* Set up signal handlers.  */
  sigint_remote_token =
    create_async_signal_handler (async_remote_interrupt, NULL);
  sigint_remote_twice_token =
    create_async_signal_handler (inferior_event_handler_wrapper, NULL);

#if 0
  init_remote_threadtests ();
#endif

  /* set/show remote ...  */

  add_prefix_cmd ("remote", class_maintenance, set_remote_cmd, _("\
Remote protocol specific variables\n\
Configure various remote-protocol specific variables such as\n\
the packets being used"),
                  &remote_set_cmdlist, "set remote ",
                  0 /* allow-unknown */, &setlist);
  add_prefix_cmd ("remote", class_maintenance, show_remote_cmd, _("\
Remote protocol specific variables\n\
Configure various remote-protocol specific variables such as\n\
the packets being used"),
                  &remote_show_cmdlist, "show remote ",
                  0 /* allow-unknown */, &showlist);

  add_cmd ("compare-sections", class_obscure, compare_sections_command, _("\
Compare section data on target to the exec file.\n\
Argument is a single section name (default: all loaded sections)."),
           &cmdlist);

  add_cmd ("packet", class_maintenance, packet_command, _("\
Send an arbitrary packet to a remote target.\n\
   maintenance packet TEXT\n\
If GDB is talking to an inferior via the GDB serial protocol, then\n\
this command sends the string TEXT to the inferior, and displays the\n\
response packet.  GDB supplies the initial `$' character, and the\n\
terminating `#' character and checksum."),
           &maintenancelist);

  add_setshow_boolean_cmd ("remotebreak", no_class, &remote_break, _("\
Set whether to send break if interrupted."), _("\
Show whether to send break if interrupted."), _("\
If set, a break, instead of a cntrl-c, is sent to the remote target."),
                           NULL, NULL, /* FIXME: i18n: Whether to send break if interrupted is %s.  */
                           &setlist, &showlist);

  /* Install commands for configuring memory read/write packets.  */

  add_cmd ("remotewritesize", no_class, set_memory_write_packet_size, _("\
Set the maximum number of bytes per memory write packet (deprecated)."),
           &setlist);
  add_cmd ("remotewritesize", no_class, show_memory_write_packet_size, _("\
Show the maximum number of bytes per memory write packet (deprecated)."),
           &showlist);
  add_cmd ("memory-write-packet-size", no_class,
           set_memory_write_packet_size, _("\
Set the maximum number of bytes per memory-write packet.\n\
Specify the number of bytes in a packet or 0 (zero) for the\n\
default packet size.  The actual limit is further reduced\n\
dependent on the target.  Specify ``fixed'' to disable the\n\
further restriction and ``limit'' to enable that restriction."),
           &remote_set_cmdlist);
  add_cmd ("memory-read-packet-size", no_class,
           set_memory_read_packet_size, _("\
Set the maximum number of bytes per memory-read packet.\n\
Specify the number of bytes in a packet or 0 (zero) for the\n\
default packet size.  The actual limit is further reduced\n\
dependent on the target.  Specify ``fixed'' to disable the\n\
further restriction and ``limit'' to enable that restriction."),
           &remote_set_cmdlist);
  add_cmd ("memory-write-packet-size", no_class,
           show_memory_write_packet_size,
           _("Show the maximum number of bytes per memory-write packet."),
           &remote_show_cmdlist);
  add_cmd ("memory-read-packet-size", no_class,
           show_memory_read_packet_size,
           _("Show the maximum number of bytes per memory-read packet."),
           &remote_show_cmdlist);

  add_setshow_zinteger_cmd ("hardware-watchpoint-limit", no_class,
                            &remote_hw_watchpoint_limit, _("\
Set the maximum number of target hardware watchpoints."), _("\
Show the maximum number of target hardware watchpoints."), _("\
Specify a negative limit for unlimited."),
                            NULL, NULL, /* FIXME: i18n: The maximum number of target hardware watchpoints is %s.  */
                            &remote_set_cmdlist, &remote_show_cmdlist);
  add_setshow_zinteger_cmd ("hardware-breakpoint-limit", no_class,
                            &remote_hw_breakpoint_limit, _("\
Set the maximum number of target hardware breakpoints."), _("\
Show the maximum number of target hardware breakpoints."), _("\
Specify a negative limit for unlimited."),
                            NULL, NULL, /* FIXME: i18n: The maximum number of target hardware breakpoints is %s.  */
                            &remote_set_cmdlist, &remote_show_cmdlist);

  add_setshow_integer_cmd ("remoteaddresssize", class_obscure,
                           &remote_address_size, _("\
Set the maximum size of the address (in bits) in a memory packet."), _("\
Show the maximum size of the address (in bits) in a memory packet."), NULL,
                           NULL,
                           NULL, /* FIXME: i18n: */
                           &setlist, &showlist);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_X],
                         "X", "binary-download", 1);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_vCont],
                         "vCont", "verbose-resume", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_QPassSignals],
                         "QPassSignals", "pass-signals", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_qSymbol],
                         "qSymbol", "symbol-lookup", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_P],
                         "P", "set-register", 1);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_p],
                         "p", "fetch-register", 1);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_Z0],
                         "Z0", "software-breakpoint", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_Z1],
                         "Z1", "hardware-breakpoint", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_Z2],
                         "Z2", "write-watchpoint", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_Z3],
                         "Z3", "read-watchpoint", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_Z4],
                         "Z4", "access-watchpoint", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_qXfer_auxv],
                         "qXfer:auxv:read", "read-aux-vector", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_qXfer_features],
                         "qXfer:features:read", "target-features", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_qXfer_libraries],
                         "qXfer:libraries:read", "library-info", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_qXfer_memory_map],
                         "qXfer:memory-map:read", "memory-map", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_qXfer_spu_read],
                         "qXfer:spu:read", "read-spu-object", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_qXfer_spu_write],
                         "qXfer:spu:write", "write-spu-object", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_qGetTLSAddr],
                         "qGetTLSAddr", "get-thread-local-storage-address",
                         0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_qSupported],
                         "qSupported", "supported-packets", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_qSearch_memory],
                         "qSearch:memory", "search-memory", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_vFile_open],
                         "vFile:open", "hostio-open", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_vFile_pread],
                         "vFile:pread", "hostio-pread", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_vFile_pwrite],
                         "vFile:pwrite", "hostio-pwrite", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_vFile_close],
                         "vFile:close", "hostio-close", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_vFile_unlink],
                         "vFile:unlink", "hostio-unlink", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_vAttach],
                         "vAttach", "attach", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_vRun],
                         "vRun", "run", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_QStartNoAckMode],
                         "QStartNoAckMode", "noack", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_vKill],
                         "vKill", "kill", 0);

  /* Keep the old ``set remote Z-packet ...'' working.  Each individual
     Z sub-packet has its own set and show commands, but users may
     have sets to this variable in their .gdbinit files (or in their
     documentation).  */
  add_setshow_auto_boolean_cmd ("Z-packet", class_obscure,
                                &remote_Z_packet_detect, _("\
Set use of remote protocol `Z' packets"), _("\
Show use of remote protocol `Z' packets "), _("\
When set, GDB will attempt to use the remote breakpoint and watchpoint\n\
packets."),
                                set_remote_protocol_Z_packet_cmd,
                                show_remote_protocol_Z_packet_cmd, /* FIXME: i18n: Use of remote protocol `Z' packets is %s.  */
                                &remote_set_cmdlist, &remote_show_cmdlist);

  add_prefix_cmd ("remote", class_files, remote_command, _("\
Manipulate files on the remote system\n\
Transfer files to and from the remote target system."),
                  &remote_cmdlist, "remote ",
                  0 /* allow-unknown */, &cmdlist);

  add_cmd ("put", class_files, remote_put_command,
           _("Copy a local file to the remote system."),
           &remote_cmdlist);

  add_cmd ("get", class_files, remote_get_command,
           _("Copy a remote file to the local system."),
           &remote_cmdlist);

  add_cmd ("delete", class_files, remote_delete_command,
           _("Delete a remote file."),
           &remote_cmdlist);

  remote_exec_file = xstrdup ("");
  add_setshow_string_noescape_cmd ("exec-file", class_files,
                                   &remote_exec_file, _("\
Set the remote pathname for \"run\""), _("\
Show the remote pathname for \"run\""), NULL, NULL, NULL,
                                   &remote_set_cmdlist, &remote_show_cmdlist);

  /* Eventually initialize fileio.  See fileio.c */
  initialize_remote_fileio (remote_set_cmdlist, remote_show_cmdlist);

  /* Take advantage of the fact that the LWP field is not used, to tag
     special ptids with it set to != 0.  */
  magic_null_ptid = ptid_build (42000, 1, -1);
  not_sent_ptid = ptid_build (42000, 1, -2);
  any_thread_ptid = ptid_build (42000, 1, 0);
}