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