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   char fdopen[MAX_CALLBACK_FDS];
 127   char alwaysopen[MAX_CALLBACK_FDS];
 128
 129   /* System call numbers.  */
 130   CB_TARGET_DEFS_MAP *syscall_map;
 131   /* Errno values.  */
 132   CB_TARGET_DEFS_MAP *errno_map;
 133   /* Flags to the open system call.  */
 134   CB_TARGET_DEFS_MAP *open_map;
 135   /* Signal numbers.  */
 136   CB_TARGET_DEFS_MAP *signal_map;
 137   /* Layout of `stat' struct.
 138      The format is a series of "name,length" pairs separated by colons.
 139      Empty space is indicated with a `name' of "space".
 140      All padding must be explicitly mentioned.
 141      Lengths are in bytes.  If this needs to be extended to bits,
 142      use "name.bits".
 143      Example: "st_dev,4:st_ino,4:st_mode,4:..."  */
 144   const char *stat_map;
 145
 146   /* Marker for those wanting to do sanity checks.
 147      This should remain the last member of this struct to help catch
 148      miscompilation errors. */
 149 #define HOST_CALLBACK_MAGIC 4705 /* teds constant */
 150   int magic;
 151 };
 152
 153 extern host_callback default_callback;
 154 \f
 155 /* Canonical versions of system call numbers.
 156    It's not intended to willy-nilly throw every system call ever heard
 157    of in here.  Only include those that have an important use.
 158    ??? One can certainly start a discussion over the ones that are currently
 159    here, but that will always be true.  */
 160
 161 /* These are used by the ANSI C support of libc.  */
 162 #define CB_SYS_exit     1
 163 #define CB_SYS_open     2
 164 #define CB_SYS_close    3
 165 #define CB_SYS_read     4
 166 #define CB_SYS_write    5
 167 #define CB_SYS_lseek    6
 168 #define CB_SYS_unlink   7
 169 #define CB_SYS_getpid   8
 170 #define CB_SYS_kill     9
 171 #define CB_SYS_fstat    10
 172 /*#define CB_SYS_sbrk   11 - not currently a system call, but reserved.  */
 173
 174 /* ARGV support.  */
 175 #define CB_SYS_argvlen  12
 176 #define CB_SYS_argv     13
 177
 178 /* These are extras added for one reason or another.  */
 179 #define CB_SYS_chdir    14
 180 #define CB_SYS_stat     15
 181 #define CB_SYS_chmod    16
 182 #define CB_SYS_utime    17
 183 #define CB_SYS_time     18
 184 \f
 185 /* Struct use to pass and return information necessary to perform a
 186    system call.  */
 187 /* FIXME: Need to consider target word size.  */
 188
 189 typedef struct cb_syscall {
 190   /* The target's value of what system call to perform.  */
 191   int func;
 192   /* The arguments to the syscall.  */
 193   long arg1, arg2, arg3, arg4;
 194
 195   /* The result.  */
 196   long result;
 197   /* Some system calls have two results.  */
 198   long result2;
 199   /* The target's errno value, or 0 if success.
 200      This is converted to the target's value with host_to_target_errno.  */
 201   int errcode;
 202
 203   /* Working space to be used by memory read/write callbacks.  */
 204   PTR p1;
 205   PTR p2;
 206   long x1,x2;
 207
 208   /* Callbacks for reading/writing memory (e.g. for read/write syscalls).
 209      ??? long or unsigned long might be better to use for the `count'
 210      argument here.  We mimic sim_{read,write} for now.  Be careful to
 211      test any changes with -Wall -Werror, mixed signed comparisons
 212      will get you.  */
 213   int (*read_mem) PARAMS ((host_callback * /*cb*/, struct cb_syscall * /*sc*/,
 214                            unsigned long /*taddr*/, char * /*buf*/,
 215                            int /*bytes*/));
 216   int (*write_mem) PARAMS ((host_callback * /*cb*/, struct cb_syscall * /*sc*/,
 217                             unsigned long /*taddr*/, const char * /*buf*/,
 218                             int /*bytes*/));
 219
 220   /* For sanity checking, should be last entry.  */
 221   int magic;
 222 } CB_SYSCALL;
 223
 224 /* Magic number sanity checker.  */
 225 #define CB_SYSCALL_MAGIC 0x12344321
 226
 227 /* Macro to initialize CB_SYSCALL.  Called first, before filling in
 228    any fields.  */
 229 #define CB_SYSCALL_INIT(sc) \
 230 do { \
 231   memset ((sc), 0, sizeof (*(sc))); \
 232   (sc)->magic = CB_SYSCALL_MAGIC; \
 233 } while (0)
 234 \f
 235 /* Return codes for various interface routines.  */
 236
 237 typedef enum {
 238   CB_RC_OK = 0,
 239   /* generic error */
 240   CB_RC_ERR,
 241   /* either file not found or no read access */
 242   CB_RC_ACCESS,
 243   CB_RC_NO_MEM
 244 } CB_RC;
 245
 246 /* Read in target values for system call numbers, errno values, signals.  */
 247 CB_RC cb_read_target_syscall_maps PARAMS ((host_callback *, const char *));
 248
 249 /* Translate target to host syscall function numbers.  */
 250 int cb_target_to_host_syscall PARAMS ((host_callback *, int));
 251
 252 /* Translate host to target errno value.  */
 253 int cb_host_to_target_errno PARAMS ((host_callback *, int));
 254
 255 /* Translate target to host open flags.  */
 256 int cb_target_to_host_open PARAMS ((host_callback *, int));
 257
 258 /* Translate target signal number to host.  */
 259 int cb_target_to_host_signal PARAMS ((host_callback *, int));
 260
 261 /* Translate host signal number to target.  */
 262 int cb_host_to_target_signal PARAMS ((host_callback *, int));
 263
 264 /* Translate host stat struct to target.
 265    If stat struct ptr is NULL, just compute target stat struct size.
 266    Result is size of target stat struct or 0 if error.  */
 267 int cb_host_to_target_stat PARAMS ((host_callback *, const struct stat *, PTR));
 268
 269 /* Perform a system call.  */
 270 CB_RC cb_syscall PARAMS ((host_callback *, CB_SYSCALL *));
 271
 272 #endif