gdb/corefile.c

   1 /* Core dump and executable file functions above target vector, for GDB.
   2
   3    Copyright (C) 1986-1987, 1989, 1991-1994, 1996-2001, 2003, 2006-2012
   4    Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "defs.h"
  22 #include "gdb_string.h"
  23 #include <errno.h>
  24 #include <signal.h>
  25 #include <fcntl.h>
  26 #include "inferior.h"
  27 #include "symtab.h"
  28 #include "command.h"
  29 #include "gdbcmd.h"
  30 #include "bfd.h"
  31 #include "target.h"
  32 #include "gdbcore.h"
  33 #include "dis-asm.h"
  34 #include "gdb_stat.h"
  35 #include "completer.h"
  36 #include "exceptions.h"
  37
  38 /* Local function declarations.  */
  39
  40 extern void _initialize_core (void);
  41 static void call_extra_exec_file_hooks (char *filename);
  42
  43 /* You can have any number of hooks for `exec_file_command' command to
  44    call.  If there's only one hook, it is set in exec_file_display
  45    hook.  If there are two or more hooks, they are set in
  46    exec_file_extra_hooks[], and deprecated_exec_file_display_hook is
  47    set to a function that calls all of them.  This extra complexity is
  48    needed to preserve compatibility with old code that assumed that
  49    only one hook could be set, and which called
  50    deprecated_exec_file_display_hook directly.  */
  51
  52 typedef void (*hook_type) (char *);
  53
  54 hook_type deprecated_exec_file_display_hook;    /* The original hook.  */
  55 static hook_type *exec_file_extra_hooks;        /* Array of additional
  56                                                    hooks.  */
  57 static int exec_file_hook_count = 0;            /* Size of array.  */
  58
  59 /* Binary file diddling handle for the core file.  */
  60
  61 bfd *core_bfd = NULL;
  62
  63 /* corelow.c target (if included for this gdb target).  */
  64
  65 struct target_ops *core_target;
  66 \f
  67
  68 /* Backward compatability with old way of specifying core files.  */
  69
  70 void
  71 core_file_command (char *filename, int from_tty)
  72 {
  73   dont_repeat ();               /* Either way, seems bogus.  */
  74
  75   if (core_target == NULL)
  76     error (_("GDB can't read core files on this machine."));
  77
  78   if (!filename)
  79     (core_target->to_detach) (core_target, filename, from_tty);
  80   else
  81     (core_target->to_open) (filename, from_tty);
  82 }
  83 \f
  84
  85 /* If there are two or more functions that wish to hook into
  86    exec_file_command, this function will call all of the hook
  87    functions.  */
  88
  89 static void
  90 call_extra_exec_file_hooks (char *filename)
  91 {
  92   int i;
  93
  94   for (i = 0; i < exec_file_hook_count; i++)
  95     (*exec_file_extra_hooks[i]) (filename);
  96 }
  97
  98 /* Call this to specify the hook for exec_file_command to call back.
  99    This is called from the x-window display code.  */
 100
 101 void
 102 specify_exec_file_hook (void (*hook) (char *))
 103 {
 104   hook_type *new_array;
 105
 106   if (deprecated_exec_file_display_hook != NULL)
 107     {
 108       /* There's already a hook installed.  Arrange to have both it
 109          and the subsequent hooks called.  */
 110       if (exec_file_hook_count == 0)
 111         {
 112           /* If this is the first extra hook, initialize the hook
 113              array.  */
 114           exec_file_extra_hooks = (hook_type *)
 115             xmalloc (sizeof (hook_type));
 116           exec_file_extra_hooks[0] = deprecated_exec_file_display_hook;
 117           deprecated_exec_file_display_hook = call_extra_exec_file_hooks;
 118           exec_file_hook_count = 1;
 119         }
 120
 121       /* Grow the hook array by one and add the new hook to the end.
 122          Yes, it's inefficient to grow it by one each time but since
 123          this is hardly ever called it's not a big deal.  */
 124       exec_file_hook_count++;
 125       new_array = (hook_type *)
 126         xrealloc (exec_file_extra_hooks,
 127                   exec_file_hook_count * sizeof (hook_type));
 128       exec_file_extra_hooks = new_array;
 129       exec_file_extra_hooks[exec_file_hook_count - 1] = hook;
 130     }
 131   else
 132     deprecated_exec_file_display_hook = hook;
 133 }
 134
 135 void
 136 reopen_exec_file (void)
 137 {
 138   char *filename;
 139   int res;
 140   struct stat st;
 141   struct cleanup *cleanups;
 142
 143   /* Don't do anything if there isn't an exec file.  */
 144   if (exec_bfd == NULL)
 145     return;
 146
 147   /* If the timestamp of the exec file has changed, reopen it.  */
 148   filename = xstrdup (bfd_get_filename (exec_bfd));
 149   cleanups = make_cleanup (xfree, filename);
 150   res = stat (filename, &st);
 151
 152   if (exec_bfd_mtime && exec_bfd_mtime != st.st_mtime)
 153     exec_file_attach (filename, 0);
 154   else
 155     /* If we accessed the file since last opening it, close it now;
 156        this stops GDB from holding the executable open after it
 157        exits.  */
 158     bfd_cache_close_all ();
 159
 160   do_cleanups (cleanups);
 161 }
 162 \f
 163 /* If we have both a core file and an exec file,
 164    print a warning if they don't go together.  */
 165
 166 void
 167 validate_files (void)
 168 {
 169   if (exec_bfd && core_bfd)
 170     {
 171       if (!core_file_matches_executable_p (core_bfd, exec_bfd))
 172         warning (_("core file may not match specified executable file."));
 173       else if (bfd_get_mtime (exec_bfd) > bfd_get_mtime (core_bfd))
 174         warning (_("exec file is newer than core file."));
 175     }
 176 }
 177
 178 /* Return the name of the executable file as a string.
 179    ERR nonzero means get error if there is none specified;
 180    otherwise return 0 in that case.  */
 181
 182 char *
 183 get_exec_file (int err)
 184 {
 185   if (exec_bfd)
 186     return bfd_get_filename (exec_bfd);
 187   if (!err)
 188     return NULL;
 189
 190   error (_("No executable file specified.\n\
 191 Use the \"file\" or \"exec-file\" command."));
 192   return NULL;
 193 }
 194 \f
 195
 196 /* Report a memory error by throwing a MEMORY_ERROR error.  */
 197
 198 void
 199 memory_error (int status, CORE_ADDR memaddr)
 200 {
 201   if (status == EIO)
 202     /* Actually, address between memaddr and memaddr + len was out of
 203        bounds.  */
 204     throw_error (MEMORY_ERROR,
 205                  _("Cannot access memory at address %s"),
 206                  paddress (target_gdbarch, memaddr));
 207   else
 208     throw_error (MEMORY_ERROR,
 209                  _("Error accessing memory address %s: %s."),
 210                  paddress (target_gdbarch, memaddr),
 211                  safe_strerror (status));
 212 }
 213
 214 /* Same as target_read_memory, but report an error if can't read.  */
 215
 216 void
 217 read_memory (CORE_ADDR memaddr, gdb_byte *myaddr, int len)
 218 {
 219   int status;
 220
 221   status = target_read_memory (memaddr, myaddr, len);
 222   if (status != 0)
 223     memory_error (status, memaddr);
 224 }
 225
 226 /* Same as target_read_stack, but report an error if can't read.  */
 227
 228 void
 229 read_stack (CORE_ADDR memaddr, gdb_byte *myaddr, int len)
 230 {
 231   int status;
 232
 233   status = target_read_stack (memaddr, myaddr, len);
 234   if (status != 0)
 235     memory_error (status, memaddr);
 236 }
 237
 238 /* Argument / return result struct for use with
 239    do_captured_read_memory_integer().  MEMADDR and LEN are filled in
 240    by gdb_read_memory_integer().  RESULT is the contents that were
 241    successfully read from MEMADDR of length LEN.  */
 242
 243 struct captured_read_memory_integer_arguments
 244 {
 245   CORE_ADDR memaddr;
 246   int len;
 247   enum bfd_endian byte_order;
 248   LONGEST result;
 249 };
 250
 251 /* Helper function for gdb_read_memory_integer().  DATA must be a
 252    pointer to a captured_read_memory_integer_arguments struct.
 253    Return 1 if successful.  Note that the catch_errors() interface
 254    will return 0 if an error occurred while reading memory.  This
 255    choice of return code is so that we can distinguish between
 256    success and failure.  */
 257
 258 static int
 259 do_captured_read_memory_integer (void *data)
 260 {
 261   struct captured_read_memory_integer_arguments *args
 262     = (struct captured_read_memory_integer_arguments*) data;
 263   CORE_ADDR memaddr = args->memaddr;
 264   int len = args->len;
 265   enum bfd_endian byte_order = args->byte_order;
 266
 267   args->result = read_memory_integer (memaddr, len, byte_order);
 268
 269   return 1;
 270 }
 271
 272 /* Read memory at MEMADDR of length LEN and put the contents in
 273    RETURN_VALUE.  Return 0 if MEMADDR couldn't be read and non-zero
 274    if successful.  */
 275
 276 int
 277 safe_read_memory_integer (CORE_ADDR memaddr, int len,
 278                           enum bfd_endian byte_order,
 279                           LONGEST *return_value)
 280 {
 281   int status;
 282   struct captured_read_memory_integer_arguments args;
 283
 284   args.memaddr = memaddr;
 285   args.len = len;
 286   args.byte_order = byte_order;
 287
 288   status = catch_errors (do_captured_read_memory_integer, &args,
 289                          "", RETURN_MASK_ALL);
 290   if (status)
 291     *return_value = args.result;
 292
 293   return status;
 294 }
 295
 296 LONGEST
 297 read_memory_integer (CORE_ADDR memaddr, int len,
 298                      enum bfd_endian byte_order)
 299 {
 300   gdb_byte buf[sizeof (LONGEST)];
 301
 302   read_memory (memaddr, buf, len);
 303   return extract_signed_integer (buf, len, byte_order);
 304 }
 305
 306 ULONGEST
 307 read_memory_unsigned_integer (CORE_ADDR memaddr, int len,
 308                               enum bfd_endian byte_order)
 309 {
 310   gdb_byte buf[sizeof (ULONGEST)];
 311
 312   read_memory (memaddr, buf, len);
 313   return extract_unsigned_integer (buf, len, byte_order);
 314 }
 315
 316 void
 317 read_memory_string (CORE_ADDR memaddr, char *buffer, int max_len)
 318 {
 319   char *cp;
 320   int i;
 321   int cnt;
 322
 323   cp = buffer;
 324   while (1)
 325     {
 326       if (cp - buffer >= max_len)
 327         {
 328           buffer[max_len - 1] = '\0';
 329           break;
 330         }
 331       cnt = max_len - (cp - buffer);
 332       if (cnt > 8)
 333         cnt = 8;
 334       read_memory (memaddr + (int) (cp - buffer), cp, cnt);
 335       for (i = 0; i < cnt && *cp; i++, cp++)
 336         ;                       /* null body */
 337
 338       if (i < cnt && !*cp)
 339         break;
 340     }
 341 }
 342
 343 CORE_ADDR
 344 read_memory_typed_address (CORE_ADDR addr, struct type *type)
 345 {
 346   gdb_byte *buf = alloca (TYPE_LENGTH (type));
 347
 348   read_memory (addr, buf, TYPE_LENGTH (type));
 349   return extract_typed_address (buf, type);
 350 }
 351
 352 /* Same as target_write_memory, but report an error if can't
 353    write.  */
 354 void
 355 write_memory (CORE_ADDR memaddr,
 356               const bfd_byte *myaddr, int len)
 357 {
 358   int status;
 359
 360   status = target_write_memory (memaddr, myaddr, len);
 361   if (status != 0)
 362     memory_error (status, memaddr);
 363 }
 364
 365 /* Store VALUE at ADDR in the inferior as a LEN-byte unsigned
 366    integer.  */
 367 void
 368 write_memory_unsigned_integer (CORE_ADDR addr, int len,
 369                                enum bfd_endian byte_order,
 370                                ULONGEST value)
 371 {
 372   gdb_byte *buf = alloca (len);
 373
 374   store_unsigned_integer (buf, len, byte_order, value);
 375   write_memory (addr, buf, len);
 376 }
 377
 378 /* Store VALUE at ADDR in the inferior as a LEN-byte signed
 379    integer.  */
 380 void
 381 write_memory_signed_integer (CORE_ADDR addr, int len,
 382                              enum bfd_endian byte_order,
 383                              LONGEST value)
 384 {
 385   gdb_byte *buf = alloca (len);
 386
 387   store_signed_integer (buf, len, byte_order, value);
 388   write_memory (addr, buf, len);
 389 }
 390 \f
 391 /* The current default bfd target.  Points to storage allocated for
 392    gnutarget_string.  */
 393 char *gnutarget;
 394
 395 /* Same thing, except it is "auto" not NULL for the default case.  */
 396 static char *gnutarget_string;
 397 static void
 398 show_gnutarget_string (struct ui_file *file, int from_tty,
 399                        struct cmd_list_element *c,
 400                        const char *value)
 401 {
 402   fprintf_filtered (file,
 403                     _("The current BFD target is \"%s\".\n"), value);
 404 }
 405
 406 static void set_gnutarget_command (char *, int,
 407                                    struct cmd_list_element *);
 408
 409 static void
 410 set_gnutarget_command (char *ignore, int from_tty,
 411                        struct cmd_list_element *c)
 412 {
 413   if (strcmp (gnutarget_string, "auto") == 0)
 414     gnutarget = NULL;
 415   else
 416     gnutarget = gnutarget_string;
 417 }
 418
 419 /* Set the gnutarget.  */
 420 void
 421 set_gnutarget (char *newtarget)
 422 {
 423   if (gnutarget_string != NULL)
 424     xfree (gnutarget_string);
 425   gnutarget_string = xstrdup (newtarget);
 426   set_gnutarget_command (NULL, 0, NULL);
 427 }
 428
 429 void
 430 _initialize_core (void)
 431 {
 432   struct cmd_list_element *c;
 433
 434   c = add_cmd ("core-file", class_files, core_file_command, _("\
 435 Use FILE as core dump for examining memory and registers.\n\
 436 No arg means have no core file.  This command has been superseded by the\n\
 437 `target core' and `detach' commands."), &cmdlist);
 438   set_cmd_completer (c, filename_completer);
 439
 440
 441   add_setshow_string_noescape_cmd ("gnutarget", class_files,
 442                                    &gnutarget_string, _("\
 443 Set the current BFD target."), _("\
 444 Show the current BFD target."), _("\
 445 Use `set gnutarget auto' to specify automatic detection."),
 446                                    set_gnutarget_command,
 447                                    show_gnutarget_string,
 448                                    &setlist, &showlist);
 449
 450   if (getenv ("GNUTARGET"))
 451     set_gnutarget (getenv ("GNUTARGET"));
 452   else
 453     set_gnutarget ("auto");
 454 }