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 (*lstat) PARAMS ((host_callback *, const char *, struct stat *));
  97   int (*ftruncate) PARAMS ((host_callback *, int, long));
  98   int (*truncate) PARAMS ((host_callback *, const char *, long));
  99
 100   /* When present, call to the client to give it the oportunity to
 101      poll any io devices for a request to quit (indicated by a nonzero
 102      return value). */
 103   int (*poll_quit) PARAMS ((host_callback *));
 104
 105   /* Used when the target has gone away, so we can close open
 106      handles and free memory etc etc.  */
 107   int (*shutdown) PARAMS ((host_callback *));
 108   int (*init)     PARAMS ((host_callback *));
 109
 110   /* depreciated, use vprintf_filtered - Talk to the user on a console.  */
 111   void (*printf_filtered) PARAMS ((host_callback *, const char *, ...));
 112
 113   /* Talk to the user on a console.  */
 114   void (*vprintf_filtered) PARAMS ((host_callback *, const char *, va_list));
 115
 116   /* Same as vprintf_filtered but to stderr.  */
 117   void (*evprintf_filtered) PARAMS ((host_callback *, const char *, va_list));
 118
 119   /* Print an error message and "exit".
 120      In the case of gdb "exiting" means doing a longjmp back to the main
 121      command loop.  */
 122   void (*error) PARAMS ((host_callback *, const char *, ...));
 123
 124   int last_errno;               /* host format */
 125
 126   int fdmap[MAX_CALLBACK_FDS];
 127   /* fd_buddy is used to contruct circular lists of target fds that point to
 128      the same host fd.  A uniquely mapped fd points to itself; for a closed
 129      one, fd_buddy has the value -1.  The host file descriptors for stdin /
 130      stdout / stderr are never closed by the simulators, so they are put
 131      in a special fd_buddy circular list which also has MAX_CALLBACK_FDS
 132      as a member.  */
 133   /* ??? We don't have a callback entry for dup, although it is trival to
 134      implement now.  */
 135   short fd_buddy[MAX_CALLBACK_FDS+1];
 136
 137   /* System call numbers.  */
 138   CB_TARGET_DEFS_MAP *syscall_map;
 139   /* Errno values.  */
 140   CB_TARGET_DEFS_MAP *errno_map;
 141   /* Flags to the open system call.  */
 142   CB_TARGET_DEFS_MAP *open_map;
 143   /* Signal numbers.  */
 144   CB_TARGET_DEFS_MAP *signal_map;
 145   /* Layout of `stat' struct.
 146      The format is a series of "name,length" pairs separated by colons.
 147      Empty space is indicated with a `name' of "space".
 148      All padding must be explicitly mentioned.
 149      Lengths are in bytes.  If this needs to be extended to bits,
 150      use "name.bits".
 151      Example: "st_dev,4:st_ino,4:st_mode,4:..."  */
 152   const char *stat_map;
 153
 154   /* Marker for those wanting to do sanity checks.
 155      This should remain the last member of this struct to help catch
 156      miscompilation errors. */
 157 #define HOST_CALLBACK_MAGIC 4705 /* teds constant */
 158   int magic;
 159 };
 160
 161 extern host_callback default_callback;
 162 \f
 163 /* Canonical versions of system call numbers.
 164    It's not intended to willy-nilly throw every system call ever heard
 165    of in here.  Only include those that have an important use.
 166    ??? One can certainly start a discussion over the ones that are currently
 167    here, but that will always be true.  */
 168
 169 /* These are used by the ANSI C support of libc.  */
 170 #define CB_SYS_exit     1
 171 #define CB_SYS_open     2
 172 #define CB_SYS_close    3
 173 #define CB_SYS_read     4
 174 #define CB_SYS_write    5
 175 #define CB_SYS_lseek    6
 176 #define CB_SYS_unlink   7
 177 #define CB_SYS_getpid   8
 178 #define CB_SYS_kill     9
 179 #define CB_SYS_fstat    10
 180 /*#define CB_SYS_sbrk   11 - not currently a system call, but reserved.  */
 181
 182 /* ARGV support.  */
 183 #define CB_SYS_argvlen  12
 184 #define CB_SYS_argv     13
 185
 186 /* These are extras added for one reason or another.  */
 187 #define CB_SYS_chdir    14
 188 #define CB_SYS_stat     15
 189 #define CB_SYS_chmod    16
 190 #define CB_SYS_utime    17
 191 #define CB_SYS_time     18
 192
 193 /* More standard syscalls.  */
 194 #define CB_SYS_lstat    19
 195 \f
 196 /* Struct use to pass and return information necessary to perform a
 197    system call.  */
 198 /* FIXME: Need to consider target word size.  */
 199
 200 typedef struct cb_syscall {
 201   /* The target's value of what system call to perform.  */
 202   int func;
 203   /* The arguments to the syscall.  */
 204   long arg1, arg2, arg3, arg4;
 205
 206   /* The result.  */
 207   long result;
 208   /* Some system calls have two results.  */
 209   long result2;
 210   /* The target's errno value, or 0 if success.
 211      This is converted to the target's value with host_to_target_errno.  */
 212   int errcode;
 213
 214   /* Working space to be used by memory read/write callbacks.  */
 215   PTR p1;
 216   PTR p2;
 217   long x1,x2;
 218
 219   /* Callbacks for reading/writing memory (e.g. for read/write syscalls).
 220      ??? long or unsigned long might be better to use for the `count'
 221      argument here.  We mimic sim_{read,write} for now.  Be careful to
 222      test any changes with -Wall -Werror, mixed signed comparisons
 223      will get you.  */
 224   int (*read_mem) PARAMS ((host_callback * /*cb*/, struct cb_syscall * /*sc*/,
 225                            unsigned long /*taddr*/, char * /*buf*/,
 226                            int /*bytes*/));
 227   int (*write_mem) PARAMS ((host_callback * /*cb*/, struct cb_syscall * /*sc*/,
 228                             unsigned long /*taddr*/, const char * /*buf*/,
 229                             int /*bytes*/));
 230
 231   /* For sanity checking, should be last entry.  */
 232   int magic;
 233 } CB_SYSCALL;
 234
 235 /* Magic number sanity checker.  */
 236 #define CB_SYSCALL_MAGIC 0x12344321
 237
 238 /* Macro to initialize CB_SYSCALL.  Called first, before filling in
 239    any fields.  */
 240 #define CB_SYSCALL_INIT(sc) \
 241 do { \
 242   memset ((sc), 0, sizeof (*(sc))); \
 243   (sc)->magic = CB_SYSCALL_MAGIC; \
 244 } while (0)
 245 \f
 246 /* Return codes for various interface routines.  */
 247
 248 typedef enum {
 249   CB_RC_OK = 0,
 250   /* generic error */
 251   CB_RC_ERR,
 252   /* either file not found or no read access */
 253   CB_RC_ACCESS,
 254   CB_RC_NO_MEM
 255 } CB_RC;
 256
 257 /* Read in target values for system call numbers, errno values, signals.  */
 258 CB_RC cb_read_target_syscall_maps PARAMS ((host_callback *, const char *));
 259
 260 /* Translate target to host syscall function numbers.  */
 261 int cb_target_to_host_syscall PARAMS ((host_callback *, int));
 262
 263 /* Translate host to target errno value.  */
 264 int cb_host_to_target_errno PARAMS ((host_callback *, int));
 265
 266 /* Translate target to host open flags.  */
 267 int cb_target_to_host_open PARAMS ((host_callback *, int));
 268
 269 /* Translate target signal number to host.  */
 270 int cb_target_to_host_signal PARAMS ((host_callback *, int));
 271
 272 /* Translate host signal number to target.  */
 273 int cb_host_to_target_signal PARAMS ((host_callback *, int));
 274
 275 /* Translate host stat struct to target.
 276    If stat struct ptr is NULL, just compute target stat struct size.
 277    Result is size of target stat struct or 0 if error.  */
 278 int cb_host_to_target_stat PARAMS ((host_callback *, const struct stat *, PTR));
 279
 280 /* Perform a system call.  */
 281 CB_RC cb_syscall PARAMS ((host_callback *, CB_SYSCALL *));
 282
 283 #endif