gdb/corefile.c

   1 /* Core dump and executable file functions above target vector, for GDB.
   2
   3    Copyright (C) 1986-2013 Free Software Foundation, Inc.
   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 3 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, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "gdb_string.h"
  22 #include <errno.h>
  23 #include <signal.h>
  24 #include <fcntl.h>
  25 #include "inferior.h"
  26 #include "symtab.h"
  27 #include "command.h"
  28 #include "gdbcmd.h"
  29 #include "bfd.h"
  30 #include "target.h"
  31 #include "gdbcore.h"
  32 #include "dis-asm.h"
  33 #include "gdb_stat.h"
  34 #include "completer.h"
  35 #include "exceptions.h"
  36 #include "observer.h"
  37 #include "cli/cli-utils.h"
  38
  39 /* Local function declarations.  */
  40
  41 extern void _initialize_core (void);
  42 static void call_extra_exec_file_hooks (char *filename);
  43
  44 /* You can have any number of hooks for `exec_file_command' command to
  45    call.  If there's only one hook, it is set in exec_file_display
  46    hook.  If there are two or more hooks, they are set in
  47    exec_file_extra_hooks[], and deprecated_exec_file_display_hook is
  48    set to a function that calls all of them.  This extra complexity is
  49    needed to preserve compatibility with old code that assumed that
  50    only one hook could be set, and which called
  51    deprecated_exec_file_display_hook directly.  */
  52
  53 typedef void (*hook_type) (char *);
  54
  55 hook_type deprecated_exec_file_display_hook;    /* The original hook.  */
  56 static hook_type *exec_file_extra_hooks;        /* Array of additional
  57                                                    hooks.  */
  58 static int exec_file_hook_count = 0;            /* Size of array.  */
  59
  60 /* Binary file diddling handle for the core file.  */
  61
  62 bfd *core_bfd = NULL;
  63
  64 /* corelow.c target.  It is never NULL after GDB initialization.  */
  65
  66 struct target_ops *core_target;
  67 \f
  68
  69 /* Backward compatability with old way of specifying core files.  */
  70
  71 void
  72 core_file_command (char *filename, int from_tty)
  73 {
  74   dont_repeat ();               /* Either way, seems bogus.  */
  75
  76   gdb_assert (core_target != NULL);
  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 target xfer memory error by throwing a suitable
 197    exception.  */
 198
 199 static void
 200 target_xfer_memory_error (enum target_xfer_error err, CORE_ADDR memaddr)
 201 {
 202   switch (err)
 203     {
 204     case TARGET_XFER_E_IO:
 205       /* Actually, address between memaddr and memaddr + len was out of
 206          bounds.  */
 207       throw_error (MEMORY_ERROR,
 208                    _("Cannot access memory at address %s"),
 209                    paddress (target_gdbarch (), memaddr));
 210     case TARGET_XFER_E_UNAVAILABLE:
 211       throw_error (NOT_AVAILABLE_ERROR,
 212                    _("Memory at address %s unavailable."),
 213                    paddress (target_gdbarch (), memaddr));
 214     default:
 215       internal_error (__FILE__, __LINE__,
 216                       "unhandled target_xfer_error: %s (%s)",
 217                       target_xfer_error_to_string (err),
 218                       plongest (err));
 219     }
 220 }
 221
 222 /* Report a memory error by throwing a MEMORY_ERROR error.  */
 223
 224 void
 225 memory_error (int status, CORE_ADDR memaddr)
 226 {
 227   if (status == EIO)
 228     target_xfer_memory_error (TARGET_XFER_E_IO, memaddr);
 229   else
 230     throw_error (MEMORY_ERROR,
 231                  _("Error accessing memory address %s: %s."),
 232                  paddress (target_gdbarch (), memaddr),
 233                  safe_strerror (status));
 234 }
 235
 236 /* Same as target_read_memory, but report an error if can't read.  */
 237
 238 void
 239 read_memory (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len)
 240 {
 241   LONGEST xfered = 0;
 242
 243   while (xfered < len)
 244     {
 245       LONGEST xfer = target_xfer_partial (current_target.beneath,
 246                                           TARGET_OBJECT_MEMORY, NULL,
 247                                           myaddr + xfered, NULL,
 248                                           memaddr + xfered, len - xfered);
 249
 250       if (xfer == 0)
 251         target_xfer_memory_error (TARGET_XFER_E_IO, memaddr + xfered);
 252       if (xfer < 0)
 253         target_xfer_memory_error (xfer, memaddr + xfered);
 254       xfered += xfer;
 255       QUIT;
 256     }
 257 }
 258
 259 /* Same as target_read_stack, but report an error if can't read.  */
 260
 261 void
 262 read_stack (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len)
 263 {
 264   int status;
 265
 266   status = target_read_stack (memaddr, myaddr, len);
 267   if (status != 0)
 268     memory_error (status, memaddr);
 269 }
 270
 271 /* Argument / return result struct for use with
 272    do_captured_read_memory_integer().  MEMADDR and LEN are filled in
 273    by gdb_read_memory_integer().  RESULT is the contents that were
 274    successfully read from MEMADDR of length LEN.  */
 275
 276 struct captured_read_memory_integer_arguments
 277 {
 278   CORE_ADDR memaddr;
 279   int len;
 280   enum bfd_endian byte_order;
 281   LONGEST result;
 282 };
 283
 284 /* Helper function for gdb_read_memory_integer().  DATA must be a
 285    pointer to a captured_read_memory_integer_arguments struct.
 286    Return 1 if successful.  Note that the catch_errors() interface
 287    will return 0 if an error occurred while reading memory.  This
 288    choice of return code is so that we can distinguish between
 289    success and failure.  */
 290
 291 static int
 292 do_captured_read_memory_integer (void *data)
 293 {
 294   struct captured_read_memory_integer_arguments *args
 295     = (struct captured_read_memory_integer_arguments*) data;
 296   CORE_ADDR memaddr = args->memaddr;
 297   int len = args->len;
 298   enum bfd_endian byte_order = args->byte_order;
 299
 300   args->result = read_memory_integer (memaddr, len, byte_order);
 301
 302   return 1;
 303 }
 304
 305 /* Read memory at MEMADDR of length LEN and put the contents in
 306    RETURN_VALUE.  Return 0 if MEMADDR couldn't be read and non-zero
 307    if successful.  */
 308
 309 int
 310 safe_read_memory_integer (CORE_ADDR memaddr, int len,
 311                           enum bfd_endian byte_order,
 312                           LONGEST *return_value)
 313 {
 314   int status;
 315   struct captured_read_memory_integer_arguments args;
 316
 317   args.memaddr = memaddr;
 318   args.len = len;
 319   args.byte_order = byte_order;
 320
 321   status = catch_errors (do_captured_read_memory_integer, &args,
 322                          "", RETURN_MASK_ALL);
 323   if (status)
 324     *return_value = args.result;
 325
 326   return status;
 327 }
 328
 329 LONGEST
 330 read_memory_integer (CORE_ADDR memaddr, int len,
 331                      enum bfd_endian byte_order)
 332 {
 333   gdb_byte buf[sizeof (LONGEST)];
 334
 335   read_memory (memaddr, buf, len);
 336   return extract_signed_integer (buf, len, byte_order);
 337 }
 338
 339 ULONGEST
 340 read_memory_unsigned_integer (CORE_ADDR memaddr, int len,
 341                               enum bfd_endian byte_order)
 342 {
 343   gdb_byte buf[sizeof (ULONGEST)];
 344
 345   read_memory (memaddr, buf, len);
 346   return extract_unsigned_integer (buf, len, byte_order);
 347 }
 348
 349 void
 350 read_memory_string (CORE_ADDR memaddr, char *buffer, int max_len)
 351 {
 352   char *cp;
 353   int i;
 354   int cnt;
 355
 356   cp = buffer;
 357   while (1)
 358     {
 359       if (cp - buffer >= max_len)
 360         {
 361           buffer[max_len - 1] = '\0';
 362           break;
 363         }
 364       cnt = max_len - (cp - buffer);
 365       if (cnt > 8)
 366         cnt = 8;
 367       read_memory (memaddr + (int) (cp - buffer), (gdb_byte *) cp, cnt);
 368       for (i = 0; i < cnt && *cp; i++, cp++)
 369         ;                       /* null body */
 370
 371       if (i < cnt && !*cp)
 372         break;
 373     }
 374 }
 375
 376 CORE_ADDR
 377 read_memory_typed_address (CORE_ADDR addr, struct type *type)
 378 {
 379   gdb_byte *buf = alloca (TYPE_LENGTH (type));
 380
 381   read_memory (addr, buf, TYPE_LENGTH (type));
 382   return extract_typed_address (buf, type);
 383 }
 384
 385 /* Same as target_write_memory, but report an error if can't
 386    write.  */
 387 void
 388 write_memory (CORE_ADDR memaddr,
 389               const bfd_byte *myaddr, ssize_t len)
 390 {
 391   int status;
 392
 393   status = target_write_memory (memaddr, myaddr, len);
 394   if (status != 0)
 395     memory_error (status, memaddr);
 396 }
 397
 398 /* Same as write_memory, but notify 'memory_changed' observers.  */
 399
 400 void
 401 write_memory_with_notification (CORE_ADDR memaddr, const bfd_byte *myaddr,
 402                                 ssize_t len)
 403 {
 404   write_memory (memaddr, myaddr, len);
 405   observer_notify_memory_changed (current_inferior (), memaddr, len, myaddr);
 406 }
 407
 408 /* Store VALUE at ADDR in the inferior as a LEN-byte unsigned
 409    integer.  */
 410 void
 411 write_memory_unsigned_integer (CORE_ADDR addr, int len,
 412                                enum bfd_endian byte_order,
 413                                ULONGEST value)
 414 {
 415   gdb_byte *buf = alloca (len);
 416
 417   store_unsigned_integer (buf, len, byte_order, value);
 418   write_memory (addr, buf, len);
 419 }
 420
 421 /* Store VALUE at ADDR in the inferior as a LEN-byte signed
 422    integer.  */
 423 void
 424 write_memory_signed_integer (CORE_ADDR addr, int len,
 425                              enum bfd_endian byte_order,
 426                              LONGEST value)
 427 {
 428   gdb_byte *buf = alloca (len);
 429
 430   store_signed_integer (buf, len, byte_order, value);
 431   write_memory (addr, buf, len);
 432 }
 433 \f
 434 /* The current default bfd target.  Points to storage allocated for
 435    gnutarget_string.  */
 436 char *gnutarget;
 437
 438 /* Same thing, except it is "auto" not NULL for the default case.  */
 439 static char *gnutarget_string;
 440 static void
 441 show_gnutarget_string (struct ui_file *file, int from_tty,
 442                        struct cmd_list_element *c,
 443                        const char *value)
 444 {
 445   fprintf_filtered (file,
 446                     _("The current BFD target is \"%s\".\n"), value);
 447 }
 448
 449 static void set_gnutarget_command (char *, int,
 450                                    struct cmd_list_element *);
 451
 452 static void
 453 set_gnutarget_command (char *ignore, int from_tty,
 454                        struct cmd_list_element *c)
 455 {
 456   char *gend = gnutarget_string + strlen (gnutarget_string);
 457
 458   gend = remove_trailing_whitespace (gnutarget_string, gend);
 459   *gend = '\0';
 460
 461   if (strcmp (gnutarget_string, "auto") == 0)
 462     gnutarget = NULL;
 463   else
 464     gnutarget = gnutarget_string;
 465 }
 466
 467 /* A completion function for "set gnutarget".  */
 468
 469 static VEC (char_ptr) *
 470 complete_set_gnutarget (struct cmd_list_element *cmd,
 471                         const char *text, const char *word)
 472 {
 473   static const char **bfd_targets;
 474
 475   if (bfd_targets == NULL)
 476     {
 477       int last;
 478
 479       bfd_targets = bfd_target_list ();
 480       for (last = 0; bfd_targets[last] != NULL; ++last)
 481         ;
 482
 483       bfd_targets = xrealloc (bfd_targets, (last + 2) * sizeof (const char **));
 484       bfd_targets[last] = "auto";
 485       bfd_targets[last + 1] = NULL;
 486     }
 487
 488   return complete_on_enum (bfd_targets, text, word);
 489 }
 490
 491 /* Set the gnutarget.  */
 492 void
 493 set_gnutarget (char *newtarget)
 494 {
 495   if (gnutarget_string != NULL)
 496     xfree (gnutarget_string);
 497   gnutarget_string = xstrdup (newtarget);
 498   set_gnutarget_command (NULL, 0, NULL);
 499 }
 500
 501 void
 502 _initialize_core (void)
 503 {
 504   struct cmd_list_element *c;
 505
 506   c = add_cmd ("core-file", class_files, core_file_command, _("\
 507 Use FILE as core dump for examining memory and registers.\n\
 508 No arg means have no core file.  This command has been superseded by the\n\
 509 `target core' and `detach' commands."), &cmdlist);
 510   set_cmd_completer (c, filename_completer);
 511
 512
 513   c = add_setshow_string_noescape_cmd ("gnutarget", class_files,
 514                                        &gnutarget_string, _("\
 515 Set the current BFD target."), _("\
 516 Show the current BFD target."), _("\
 517 Use `set gnutarget auto' to specify automatic detection."),
 518                                        set_gnutarget_command,
 519                                        show_gnutarget_string,
 520                                        &setlist, &showlist);
 521   set_cmd_completer (c, complete_set_gnutarget);
 522
 523   add_alias_cmd ("g", "gnutarget", class_files, 1, &setlist);
 524
 525   if (getenv ("GNUTARGET"))
 526     set_gnutarget (getenv ("GNUTARGET"));
 527   else
 528     set_gnutarget ("auto");
 529 }