include/gdb/callback.h

   1 /* Remote target system call callback support.
   2    Copyright 1997 Free Software Foundation, Inc.
   3    Contributed by Cygnus Solutions.
   4
   5 This file is part of GDB.
   6
   7 This program is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2 of the License, or
  10 (at your option) any later version.
  11
  12 This program is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with this program; if not, write to the Free Software
  19 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  20
  21 /* This interface isn't intended to be specific to any particular kind
  22    of remote (hardware, simulator, whatever).  As such, support for it
  23    (e.g. sim/common/callback.c) should *not* live in the simulator source
  24    tree, nor should it live in the gdb source tree.  */
  25
  26 /* There are various ways to handle system calls:
  27
  28    1) Have a simulator intercept the appropriate trap instruction and
  29    directly perform the system call on behalf of the target program.
  30    This is the typical way of handling system calls for embedded targets.
  31    [Handling system calls for embedded targets isn't that much of an
  32    oxymoron as running compiler testsuites make use of the capability.]
  33
  34    This method of system call handling is done when STATE_ENVIRONMENT
  35    is ENVIRONMENT_USER.
  36
  37    2) Have a simulator emulate the hardware as much as possible.
  38    If the program running on the real hardware communicates with some sort
  39    of target manager, one would want to be able to run this program on the
  40    simulator as well.
  41
  42    This method of system call handling is done when STATE_ENVIRONMENT
  43    is ENVIRONMENT_OPERATING.
  44 */
  45
  46 #ifndef CALLBACK_H
  47 #define CALLBACK_H
  48
  49 /* ??? The reason why we check for va_start here should be documented.  */
  50
  51 #ifndef va_start
  52 #include <ansidecl.h>
  53 #ifdef ANSI_PROTOTYPES
  54 #include <stdarg.h>
  55 #else
  56 #include <varargs.h>
  57 #endif
  58 #endif
  59 \f
  60 /* Mapping of host/target values.  */
  61 /* ??? For debugging purposes, one might want to add a string of the
  62    name of the symbol.  */
  63
  64 typedef struct {
  65   int host_val;
  66   int target_val;
  67 } CB_TARGET_DEFS_MAP;
  68
  69 #define MAX_CALLBACK_FDS 10
  70
  71 /* Forward decl for stat/fstat.  */
  72 struct stat;
  73
  74 typedef struct host_callback_struct host_callback;
  75
  76 struct host_callback_struct
  77 {
  78   int (*close) PARAMS ((host_callback *,int));
  79   int (*get_errno) PARAMS ((host_callback *));
  80   int (*isatty) PARAMS ((host_callback *, int));
  81   int (*lseek) PARAMS ((host_callback *, int, long , int));
  82   int (*open) PARAMS ((host_callback *, const char*, int mode));
  83   int (*read) PARAMS ((host_callback *,int,  char *, int));
  84   int (*read_stdin) PARAMS (( host_callback *, char *, int));
  85   int (*rename) PARAMS ((host_callback *, const char *, const char *));
  86   int (*system) PARAMS ((host_callback *, const char *));
  87   long (*time) PARAMS ((host_callback *, long *));
  88   int (*unlink) PARAMS ((host_callback *, const char *));
  89   int (*write) PARAMS ((host_callback *,int, const char *, int));
  90   int (*write_stdout) PARAMS ((host_callback *, const char *, int));
  91   void (*flush_stdout) PARAMS ((host_callback *));
  92   int (*write_stderr) PARAMS ((host_callback *, const char *, int));
  93   void (*flush_stderr) PARAMS ((host_callback *));
  94   int (*stat) PARAMS ((host_callback *, const char *, struct stat *));
  95   int (*fstat) PARAMS ((host_callback *, int, struct stat *));
  96   int (*ftruncate) PARAMS ((host_callback *, int, long));
  97   int (*truncate) PARAMS ((host_callback *, const char *, long));
  98
  99   /* When present, call to the client to give it the oportunity to
 100      poll any io devices for a request to quit (indicated by a nonzero
 101      return value). */
 102   int (*poll_quit) PARAMS ((host_callback *));
 103
 104   /* Used when the target has gone away, so we can close open
 105      handles and free memory etc etc.  */
 106   int (*shutdown) PARAMS ((host_callback *));
 107   int (*init)     PARAMS ((host_callback *));
 108
 109   /* depreciated, use vprintf_filtered - Talk to the user on a console.  */
 110   void (*printf_filtered) PARAMS ((host_callback *, const char *, ...));
 111
 112   /* Talk to the user on a console.  */
 113   void (*vprintf_filtered) PARAMS ((host_callback *, const char *, va_list));
 114
 115   /* Same as vprintf_filtered but to stderr.  */
 116   void (*evprintf_filtered) PARAMS ((host_callback *, const char *, va_list));
 117
 118   /* Print an error message and "exit".
 119      In the case of gdb "exiting" means doing a longjmp back to the main
 120      command loop.  */
 121   void (*error) PARAMS ((host_callback *, const char *, ...));
 122
 123   int last_errno;               /* host format */
 124
 125   int fdmap[MAX_CALLBACK_FDS];
 126   /* fd_buddy is used to contruct circular lists of target fds that point to
 127      the same host fd.  A uniquely mapped fd points to itself; for a closed
 128      one, fd_buddy has the value -1.  The host file descriptors for stdin /
 129      stdout / stderr are never closed by the simulators, so they are put
 130      in a special fd_buddy circular list which also has MAX_CALLBACK_FDS
 131      as a member.  */
 132   /* ??? We don't have a callback entry for dup, although it is trival to
 133      implement now.  */
 134   short fd_buddy[MAX_CALLBACK_FDS+1];
 135
 136   /* System call numbers.  */
 137   CB_TARGET_DEFS_MAP *syscall_map;
 138   /* Errno values.  */
 139   CB_TARGET_DEFS_MAP *errno_map;
 140   /* Flags to the open system call.  */
 141   CB_TARGET_DEFS_MAP *open_map;
 142   /* Signal numbers.  */
 143   CB_TARGET_DEFS_MAP *signal_map;
 144   /* Layout of `stat' struct.
 145      The format is a series of "name,length" pairs separated by colons.
 146      Empty space is indicated with a `name' of "space".
 147      All padding must be explicitly mentioned.
 148      Lengths are in bytes.  If this needs to be extended to bits,
 149      use "name.bits".
 150      Example: "st_dev,4:st_ino,4:st_mode,4:..."  */
 151   const char *stat_map;
 152
 153   /* Marker for those wanting to do sanity checks.
 154      This should remain the last member of this struct to help catch
 155      miscompilation errors. */
 156 #define HOST_CALLBACK_MAGIC 4705 /* teds constant */
 157   int magic;
 158 };
 159
 160 extern host_callback default_callback;
 161 \f
 162 /* Canonical versions of system call numbers.
 163    It's not intended to willy-nilly throw every system call ever heard
 164    of in here.  Only include those that have an important use.
 165    ??? One can certainly start a discussion over the ones that are currently
 166    here, but that will always be true.  */
 167
 168 /* These are used by the ANSI C support of libc.  */
 169 #define CB_SYS_exit     1
 170 #define CB_SYS_open     2
 171 #define CB_SYS_close    3
 172 #define CB_SYS_read     4
 173 #define CB_SYS_write    5
 174 #define CB_SYS_lseek    6
 175 #define CB_SYS_unlink   7
 176 #define CB_SYS_getpid   8
 177 #define CB_SYS_kill     9
 178 #define CB_SYS_fstat    10
 179 /*#define CB_SYS_sbrk   11 - not currently a system call, but reserved.  */
 180
 181 /* ARGV support.  */
 182 #define CB_SYS_argvlen  12
 183 #define CB_SYS_argv     13
 184
 185 /* These are extras added for one reason or another.  */
 186 #define CB_SYS_chdir    14
 187 #define CB_SYS_stat     15
 188 #define CB_SYS_chmod    16
 189 #define CB_SYS_utime    17
 190 #define CB_SYS_time     18
 191 \f
 192 /* Struct use to pass and return information necessary to perform a
 193    system call.  */
 194 /* FIXME: Need to consider target word size.  */
 195
 196 typedef struct cb_syscall {
 197   /* The target's value of what system call to perform.  */
 198   int func;
 199   /* The arguments to the syscall.  */
 200   long arg1, arg2, arg3, arg4;
 201
 202   /* The result.  */
 203   long result;
 204   /* Some system calls have two results.  */
 205   long result2;
 206   /* The target's errno value, or 0 if success.
 207      This is converted to the target's value with host_to_target_errno.  */
 208   int errcode;
 209
 210   /* Working space to be used by memory read/write callbacks.  */
 211   PTR p1;
 212   PTR p2;
 213   long x1,x2;
 214
 215   /* Callbacks for reading/writing memory (e.g. for read/write syscalls).
 216      ??? long or unsigned long might be better to use for the `count'
 217      argument here.  We mimic sim_{read,write} for now.  Be careful to
 218      test any changes with -Wall -Werror, mixed signed comparisons
 219      will get you.  */
 220   int (*read_mem) PARAMS ((host_callback * /*cb*/, struct cb_syscall * /*sc*/,
 221                            unsigned long /*taddr*/, char * /*buf*/,
 222                            int /*bytes*/));
 223   int (*write_mem) PARAMS ((host_callback * /*cb*/, struct cb_syscall * /*sc*/,
 224                             unsigned long /*taddr*/, const char * /*buf*/,
 225                             int /*bytes*/));
 226
 227   /* For sanity checking, should be last entry.  */
 228   int magic;
 229 } CB_SYSCALL;
 230
 231 /* Magic number sanity checker.  */
 232 #define CB_SYSCALL_MAGIC 0x12344321
 233
 234 /* Macro to initialize CB_SYSCALL.  Called first, before filling in
 235    any fields.  */
 236 #define CB_SYSCALL_INIT(sc) \
 237 do { \
 238   memset ((sc), 0, sizeof (*(sc))); \
 239   (sc)->magic = CB_SYSCALL_MAGIC; \
 240 } while (0)
 241 \f
 242 /* Return codes for various interface routines.  */
 243
 244 typedef enum {
 245   CB_RC_OK = 0,
 246   /* generic error */
 247   CB_RC_ERR,
 248   /* either file not found or no read access */
 249   CB_RC_ACCESS,
 250   CB_RC_NO_MEM
 251 } CB_RC;
 252
 253 /* Read in target values for system call numbers, errno values, signals.  */
 254 CB_RC cb_read_target_syscall_maps PARAMS ((host_callback *, const char *));
 255
 256 /* Translate target to host syscall function numbers.  */
 257 int cb_target_to_host_syscall PARAMS ((host_callback *, int));
 258
 259 /* Translate host to target errno value.  */
 260 int cb_host_to_target_errno PARAMS ((host_callback *, int));
 261
 262 /* Translate target to host open flags.  */
 263 int cb_target_to_host_open PARAMS ((host_callback *, int));
 264
 265 /* Translate target signal number to host.  */
 266 int cb_target_to_host_signal PARAMS ((host_callback *, int));
 267
 268 /* Translate host signal number to target.  */
 269 int cb_host_to_target_signal PARAMS ((host_callback *, int));
 270
 271 /* Translate host stat struct to target.
 272    If stat struct ptr is NULL, just compute target stat struct size.
 273    Result is size of target stat struct or 0 if error.  */
 274 int cb_host_to_target_stat PARAMS ((host_callback *, const struct stat *, PTR));
 275
 276 /* Perform a system call.  */
 277 CB_RC cb_syscall PARAMS ((host_callback *, CB_SYSCALL *));
 278
 279 #endif