include/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
  97   /* When present, call to the client to give it the oportunity to
  98      poll any io devices for a request to quit (indicated by a nonzero
  99      return value). */
 100   int (*poll_quit) PARAMS ((host_callback *));
 101
 102   /* Used when the target has gone away, so we can close open
 103      handles and free memory etc etc.  */
 104   int (*shutdown) PARAMS ((host_callback *));
 105   int (*init)     PARAMS ((host_callback *));
 106
 107   /* depreciated, use vprintf_filtered - Talk to the user on a console.  */
 108   void (*printf_filtered) PARAMS ((host_callback *, const char *, ...));
 109
 110   /* Talk to the user on a console.  */
 111   void (*vprintf_filtered) PARAMS ((host_callback *, const char *, va_list));
 112
 113   /* Same as vprintf_filtered but to stderr.  */
 114   void (*evprintf_filtered) PARAMS ((host_callback *, const char *, va_list));
 115
 116   /* Print an error message and "exit".
 117      In the case of gdb "exiting" means doing a longjmp back to the main
 118      command loop.  */
 119   void (*error) PARAMS ((host_callback *, const char *, ...));
 120
 121   int last_errno;               /* host format */
 122
 123   int fdmap[MAX_CALLBACK_FDS];
 124   char fdopen[MAX_CALLBACK_FDS];
 125   char alwaysopen[MAX_CALLBACK_FDS];
 126
 127   /* System call numbers.  */
 128   CB_TARGET_DEFS_MAP *syscall_map;
 129   /* Errno values.  */
 130   CB_TARGET_DEFS_MAP *errno_map;
 131   /* Flags to the open system call.  */
 132   CB_TARGET_DEFS_MAP *open_map;
 133   /* Signal numbers.  */
 134   CB_TARGET_DEFS_MAP *signal_map;
 135   /* Layout of `stat' struct.
 136      The format is a series of "name,length" pairs separated by colons.
 137      Empty space is indicated with a `name' of "space".
 138      All padding must be explicitly mentioned.
 139      Lengths are in bytes.  If this needs to be extended to bits,
 140      use "name.bits".
 141      Example: "st_dev,4:st_ino,4:st_mode,4:..."  */
 142   const char *stat_map;
 143
 144   /* Marker for those wanting to do sanity checks.
 145      This should remain the last member of this struct to help catch
 146      miscompilation errors. */
 147 #define HOST_CALLBACK_MAGIC 4705 /* teds constant */
 148   int magic;
 149 };
 150
 151 extern host_callback default_callback;
 152 \f
 153 /* Canonical versions of system call numbers.
 154    It's not intended to willy-nilly throw every system call ever heard
 155    of in here.  Only include those that have an important use.
 156    ??? One can certainly start a discussion over the ones that are currently
 157    here, but that will always be true.  */
 158
 159 /* These are used by the ANSI C support of libc.  */
 160 #define CB_SYS_exit     1
 161 #define CB_SYS_open     2
 162 #define CB_SYS_close    3
 163 #define CB_SYS_read     4
 164 #define CB_SYS_write    5
 165 #define CB_SYS_lseek    6
 166 #define CB_SYS_unlink   7
 167 #define CB_SYS_getpid   8
 168 #define CB_SYS_kill     9
 169 #define CB_SYS_fstat    10
 170 /*#define CB_SYS_sbrk   11 - not currently a system call, but reserved.  */
 171
 172 /* ARGV support.  */
 173 #define CB_SYS_argvlen  12
 174 #define CB_SYS_argv     13
 175
 176 /* These are extras added for one reason or another.  */
 177 #define CB_SYS_chdir    14
 178 #define CB_SYS_stat     15
 179 #define CB_SYS_chmod    16
 180 #define CB_SYS_utime    17
 181 #define CB_SYS_time     18
 182 \f
 183 /* Struct use to pass and return information necessary to perform a
 184    system call.  */
 185 /* FIXME: Need to consider target word size.  */
 186
 187 typedef struct cb_syscall {
 188   /* The target's value of what system call to perform.  */
 189   int func;
 190   /* The arguments to the syscall.  */
 191   long arg1, arg2, arg3, arg4;
 192
 193   /* The result.  */
 194   long result;
 195   /* Some system calls have two results.  */
 196   long result2;
 197   /* The target's errno value, or 0 if success.
 198      This is converted to the target's value with host_to_target_errno.  */
 199   int errcode;
 200
 201   /* Working space to be used by memory read/write callbacks.  */
 202   PTR p1;
 203   PTR p2;
 204   long x1,x2;
 205
 206   /* Callbacks for reading/writing memory (e.g. for read/write syscalls).
 207      ??? long or unsigned long might be better to use for the `count'
 208      argument here.  We mimic sim_{read,write} for now.  Be careful to
 209      test any changes with -Wall -Werror, mixed signed comparisons
 210      will get you.  */
 211   int (*read_mem) PARAMS ((host_callback * /*cb*/, struct cb_syscall * /*sc*/,
 212                            unsigned long /*taddr*/, char * /*buf*/,
 213                            int /*bytes*/));
 214   int (*write_mem) PARAMS ((host_callback * /*cb*/, struct cb_syscall * /*sc*/,
 215                             unsigned long /*taddr*/, const char * /*buf*/,
 216                             int /*bytes*/));
 217
 218   /* For sanity checking, should be last entry.  */
 219   int magic;
 220 } CB_SYSCALL;
 221
 222 /* Magic number sanity checker.  */
 223 #define CB_SYSCALL_MAGIC 0x12344321
 224
 225 /* Macro to initialize CB_SYSCALL.  Called first, before filling in
 226    any fields.  */
 227 #define CB_SYSCALL_INIT(sc) \
 228 do { \
 229   memset ((sc), 0, sizeof (*(sc))); \
 230   (sc)->magic = CB_SYSCALL_MAGIC; \
 231 } while (0)
 232 \f
 233 /* Return codes for various interface routines.  */
 234
 235 typedef enum {
 236   CB_RC_OK = 0,
 237   /* generic error */
 238   CB_RC_ERR,
 239   /* either file not found or no read access */
 240   CB_RC_ACCESS,
 241   CB_RC_NO_MEM
 242 } CB_RC;
 243
 244 /* Read in target values for system call numbers, errno values, signals.  */
 245 CB_RC cb_read_target_syscall_maps PARAMS ((host_callback *, const char *));
 246
 247 /* Translate target to host syscall function numbers.  */
 248 int cb_target_to_host_syscall PARAMS ((host_callback *, int));
 249
 250 /* Translate host to target errno value.  */
 251 int cb_host_to_target_errno PARAMS ((host_callback *, int));
 252
 253 /* Translate target to host open flags.  */
 254 int cb_target_to_host_open PARAMS ((host_callback *, int));
 255
 256 /* Translate target signal number to host.  */
 257 int cb_target_to_host_signal PARAMS ((host_callback *, int));
 258
 259 /* Translate host signal number to target.  */
 260 int cb_host_to_target_signal PARAMS ((host_callback *, int));
 261
 262 /* Translate host stat struct to target.
 263    If stat struct ptr is NULL, just compute target stat struct size.
 264    Result is size of target stat struct or 0 if error.  */
 265 int cb_host_to_target_stat PARAMS ((host_callback *, const struct stat *, PTR));
 266
 267 /* Perform a system call.  */
 268 CB_RC cb_syscall PARAMS ((host_callback *, CB_SYSCALL *));
 269
 270 #endif