gdb/corefile.c

   1 /* Core dump and executable file functions above target vector, for GDB.
   2
   3    Copyright (C) 1986-2014 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 <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 <sys/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_filename)
 186     return exec_filename;
 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 char *
 197 memory_error_message (enum target_xfer_status err,
 198                       struct gdbarch *gdbarch, CORE_ADDR memaddr)
 199 {
 200   switch (err)
 201     {
 202     case TARGET_XFER_E_IO:
 203       /* Actually, address between memaddr and memaddr + len was out of
 204          bounds.  */
 205       return xstrprintf (_("Cannot access memory at address %s"),
 206                          paddress (gdbarch, memaddr));
 207     case TARGET_XFER_E_UNAVAILABLE:
 208       return xstrprintf (_("Memory at address %s unavailable."),
 209                          paddress (gdbarch, memaddr));
 210     default:
 211       internal_error (__FILE__, __LINE__,
 212                       "unhandled target_xfer_status: %s (%s)",
 213                       target_xfer_status_to_string (err),
 214                       plongest (err));
 215     }
 216 }
 217
 218 /* Report a memory error by throwing a suitable exception.  */
 219
 220 void
 221 memory_error (enum target_xfer_status err, CORE_ADDR memaddr)
 222 {
 223   char *str;
 224   enum errors exception = GDB_NO_ERROR;
 225
 226   /* Build error string.  */
 227   str = memory_error_message (err, target_gdbarch (), memaddr);
 228   make_cleanup (xfree, str);
 229
 230   /* Choose the right error to throw.  */
 231   switch (err)
 232     {
 233     case TARGET_XFER_E_IO:
 234       exception = MEMORY_ERROR;
 235       break;
 236     case TARGET_XFER_E_UNAVAILABLE:
 237       exception = NOT_AVAILABLE_ERROR;
 238       break;
 239     }
 240
 241   /* Throw it.  */
 242   throw_error (exception, ("%s"), str);
 243 }
 244
 245 /* Same as target_read_memory, but report an error if can't read.  */
 246
 247 void
 248 read_memory (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len)
 249 {
 250   ULONGEST xfered = 0;
 251
 252   while (xfered < len)
 253     {
 254       enum target_xfer_status status;
 255       ULONGEST xfered_len;
 256
 257       status = target_xfer_partial (current_target.beneath,
 258                                     TARGET_OBJECT_MEMORY, NULL,
 259                                     myaddr + xfered, NULL,
 260                                     memaddr + xfered, len - xfered,
 261                                     &xfered_len);
 262
 263       if (status == TARGET_XFER_EOF)
 264         memory_error (TARGET_XFER_E_IO, memaddr + xfered);
 265
 266       if (TARGET_XFER_STATUS_ERROR_P (status))
 267         memory_error (status, memaddr + xfered);
 268
 269       gdb_assert (status == TARGET_XFER_OK);
 270       xfered += xfered_len;
 271       QUIT;
 272     }
 273 }
 274
 275 /* Same as target_read_stack, but report an error if can't read.  */
 276
 277 void
 278 read_stack (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len)
 279 {
 280   int status;
 281
 282   status = target_read_stack (memaddr, myaddr, len);
 283   if (status != 0)
 284     memory_error (status, memaddr);
 285 }
 286
 287 /* Same as target_read_code, but report an error if can't read.  */
 288
 289 void
 290 read_code (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len)
 291 {
 292   int status;
 293
 294   status = target_read_code (memaddr, myaddr, len);
 295   if (status != 0)
 296     memory_error (status, memaddr);
 297 }
 298
 299 /* Argument / return result struct for use with
 300    do_captured_read_memory_integer().  MEMADDR and LEN are filled in
 301    by gdb_read_memory_integer().  RESULT is the contents that were
 302    successfully read from MEMADDR of length LEN.  */
 303
 304 struct captured_read_memory_integer_arguments
 305 {
 306   CORE_ADDR memaddr;
 307   int len;
 308   enum bfd_endian byte_order;
 309   LONGEST result;
 310 };
 311
 312 /* Helper function for gdb_read_memory_integer().  DATA must be a
 313    pointer to a captured_read_memory_integer_arguments struct.
 314    Return 1 if successful.  Note that the catch_errors() interface
 315    will return 0 if an error occurred while reading memory.  This
 316    choice of return code is so that we can distinguish between
 317    success and failure.  */
 318
 319 static int
 320 do_captured_read_memory_integer (void *data)
 321 {
 322   struct captured_read_memory_integer_arguments *args
 323     = (struct captured_read_memory_integer_arguments*) data;
 324   CORE_ADDR memaddr = args->memaddr;
 325   int len = args->len;
 326   enum bfd_endian byte_order = args->byte_order;
 327
 328   args->result = read_memory_integer (memaddr, len, byte_order);
 329
 330   return 1;
 331 }
 332
 333 /* Read memory at MEMADDR of length LEN and put the contents in
 334    RETURN_VALUE.  Return 0 if MEMADDR couldn't be read and non-zero
 335    if successful.  */
 336
 337 int
 338 safe_read_memory_integer (CORE_ADDR memaddr, int len,
 339                           enum bfd_endian byte_order,
 340                           LONGEST *return_value)
 341 {
 342   int status;
 343   struct captured_read_memory_integer_arguments args;
 344
 345   args.memaddr = memaddr;
 346   args.len = len;
 347   args.byte_order = byte_order;
 348
 349   status = catch_errors (do_captured_read_memory_integer, &args,
 350                          "", RETURN_MASK_ALL);
 351   if (status)
 352     *return_value = args.result;
 353
 354   return status;
 355 }
 356
 357 LONGEST
 358 read_memory_integer (CORE_ADDR memaddr, int len,
 359                      enum bfd_endian byte_order)
 360 {
 361   gdb_byte buf[sizeof (LONGEST)];
 362
 363   read_memory (memaddr, buf, len);
 364   return extract_signed_integer (buf, len, byte_order);
 365 }
 366
 367 ULONGEST
 368 read_memory_unsigned_integer (CORE_ADDR memaddr, int len,
 369                               enum bfd_endian byte_order)
 370 {
 371   gdb_byte buf[sizeof (ULONGEST)];
 372
 373   read_memory (memaddr, buf, len);
 374   return extract_unsigned_integer (buf, len, byte_order);
 375 }
 376
 377 LONGEST
 378 read_code_integer (CORE_ADDR memaddr, int len,
 379                    enum bfd_endian byte_order)
 380 {
 381   gdb_byte buf[sizeof (LONGEST)];
 382
 383   read_code (memaddr, buf, len);
 384   return extract_signed_integer (buf, len, byte_order);
 385 }
 386
 387 ULONGEST
 388 read_code_unsigned_integer (CORE_ADDR memaddr, int len,
 389                             enum bfd_endian byte_order)
 390 {
 391   gdb_byte buf[sizeof (ULONGEST)];
 392
 393   read_code (memaddr, buf, len);
 394   return extract_unsigned_integer (buf, len, byte_order);
 395 }
 396
 397 void
 398 read_memory_string (CORE_ADDR memaddr, char *buffer, int max_len)
 399 {
 400   char *cp;
 401   int i;
 402   int cnt;
 403
 404   cp = buffer;
 405   while (1)
 406     {
 407       if (cp - buffer >= max_len)
 408         {
 409           buffer[max_len - 1] = '\0';
 410           break;
 411         }
 412       cnt = max_len - (cp - buffer);
 413       if (cnt > 8)
 414         cnt = 8;
 415       read_memory (memaddr + (int) (cp - buffer), (gdb_byte *) cp, cnt);
 416       for (i = 0; i < cnt && *cp; i++, cp++)
 417         ;                       /* null body */
 418
 419       if (i < cnt && !*cp)
 420         break;
 421     }
 422 }
 423
 424 CORE_ADDR
 425 read_memory_typed_address (CORE_ADDR addr, struct type *type)
 426 {
 427   gdb_byte *buf = alloca (TYPE_LENGTH (type));
 428
 429   read_memory (addr, buf, TYPE_LENGTH (type));
 430   return extract_typed_address (buf, type);
 431 }
 432
 433 /* Same as target_write_memory, but report an error if can't
 434    write.  */
 435 void
 436 write_memory (CORE_ADDR memaddr,
 437               const bfd_byte *myaddr, ssize_t len)
 438 {
 439   int status;
 440
 441   status = target_write_memory (memaddr, myaddr, len);
 442   if (status != 0)
 443     memory_error (status, memaddr);
 444 }
 445
 446 /* Same as write_memory, but notify 'memory_changed' observers.  */
 447
 448 void
 449 write_memory_with_notification (CORE_ADDR memaddr, const bfd_byte *myaddr,
 450                                 ssize_t len)
 451 {
 452   write_memory (memaddr, myaddr, len);
 453   observer_notify_memory_changed (current_inferior (), memaddr, len, myaddr);
 454 }
 455
 456 /* Store VALUE at ADDR in the inferior as a LEN-byte unsigned
 457    integer.  */
 458 void
 459 write_memory_unsigned_integer (CORE_ADDR addr, int len,
 460                                enum bfd_endian byte_order,
 461                                ULONGEST value)
 462 {
 463   gdb_byte *buf = alloca (len);
 464
 465   store_unsigned_integer (buf, len, byte_order, value);
 466   write_memory (addr, buf, len);
 467 }
 468
 469 /* Store VALUE at ADDR in the inferior as a LEN-byte signed
 470    integer.  */
 471 void
 472 write_memory_signed_integer (CORE_ADDR addr, int len,
 473                              enum bfd_endian byte_order,
 474                              LONGEST value)
 475 {
 476   gdb_byte *buf = alloca (len);
 477
 478   store_signed_integer (buf, len, byte_order, value);
 479   write_memory (addr, buf, len);
 480 }
 481 \f
 482 /* The current default bfd target.  Points to storage allocated for
 483    gnutarget_string.  */
 484 char *gnutarget;
 485
 486 /* Same thing, except it is "auto" not NULL for the default case.  */
 487 static char *gnutarget_string;
 488 static void
 489 show_gnutarget_string (struct ui_file *file, int from_tty,
 490                        struct cmd_list_element *c,
 491                        const char *value)
 492 {
 493   fprintf_filtered (file,
 494                     _("The current BFD target is \"%s\".\n"), value);
 495 }
 496
 497 static void set_gnutarget_command (char *, int,
 498                                    struct cmd_list_element *);
 499
 500 static void
 501 set_gnutarget_command (char *ignore, int from_tty,
 502                        struct cmd_list_element *c)
 503 {
 504   char *gend = gnutarget_string + strlen (gnutarget_string);
 505
 506   gend = remove_trailing_whitespace (gnutarget_string, gend);
 507   *gend = '\0';
 508
 509   if (strcmp (gnutarget_string, "auto") == 0)
 510     gnutarget = NULL;
 511   else
 512     gnutarget = gnutarget_string;
 513 }
 514
 515 /* A completion function for "set gnutarget".  */
 516
 517 static VEC (char_ptr) *
 518 complete_set_gnutarget (struct cmd_list_element *cmd,
 519                         const char *text, const char *word)
 520 {
 521   static const char **bfd_targets;
 522
 523   if (bfd_targets == NULL)
 524     {
 525       int last;
 526
 527       bfd_targets = bfd_target_list ();
 528       for (last = 0; bfd_targets[last] != NULL; ++last)
 529         ;
 530
 531       bfd_targets = xrealloc (bfd_targets, (last + 2) * sizeof (const char **));
 532       bfd_targets[last] = "auto";
 533       bfd_targets[last + 1] = NULL;
 534     }
 535
 536   return complete_on_enum (bfd_targets, text, word);
 537 }
 538
 539 /* Set the gnutarget.  */
 540 void
 541 set_gnutarget (char *newtarget)
 542 {
 543   if (gnutarget_string != NULL)
 544     xfree (gnutarget_string);
 545   gnutarget_string = xstrdup (newtarget);
 546   set_gnutarget_command (NULL, 0, NULL);
 547 }
 548
 549 void
 550 _initialize_core (void)
 551 {
 552   struct cmd_list_element *c;
 553
 554   c = add_cmd ("core-file", class_files, core_file_command, _("\
 555 Use FILE as core dump for examining memory and registers.\n\
 556 No arg means have no core file.  This command has been superseded by the\n\
 557 `target core' and `detach' commands."), &cmdlist);
 558   set_cmd_completer (c, filename_completer);
 559
 560
 561   c = add_setshow_string_noescape_cmd ("gnutarget", class_files,
 562                                        &gnutarget_string, _("\
 563 Set the current BFD target."), _("\
 564 Show the current BFD target."), _("\
 565 Use `set gnutarget auto' to specify automatic detection."),
 566                                        set_gnutarget_command,
 567                                        show_gnutarget_string,
 568                                        &setlist, &showlist);
 569   set_cmd_completer (c, complete_set_gnutarget);
 570
 571   add_alias_cmd ("g", "gnutarget", class_files, 1, &setlist);
 572
 573   if (getenv ("GNUTARGET"))
 574     set_gnutarget (getenv ("GNUTARGET"));
 575   else
 576     set_gnutarget ("auto");
 577 }