gdb/corefile.c

   1 /* Core dump and executable file functions above target vector, for GDB.
   2
   3    Copyright (C) 1986-2016 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 <signal.h>
  22 #include <fcntl.h>
  23 #include "inferior.h"
  24 #include "symtab.h"
  25 #include "command.h"
  26 #include "gdbcmd.h"
  27 #include "bfd.h"
  28 #include "target.h"
  29 #include "gdbcore.h"
  30 #include "dis-asm.h"
  31 #include <sys/stat.h>
  32 #include "completer.h"
  33 #include "observer.h"
  34 #include "cli/cli-utils.h"
  35
  36 /* Local function declarations.  */
  37
  38 extern void _initialize_core (void);
  39
  40 /* You can have any number of hooks for `exec_file_command' command to
  41    call.  If there's only one hook, it is set in exec_file_display
  42    hook.  If there are two or more hooks, they are set in
  43    exec_file_extra_hooks[], and deprecated_exec_file_display_hook is
  44    set to a function that calls all of them.  This extra complexity is
  45    needed to preserve compatibility with old code that assumed that
  46    only one hook could be set, and which called
  47    deprecated_exec_file_display_hook directly.  */
  48
  49 typedef void (*hook_type) (const char *);
  50
  51 hook_type deprecated_exec_file_display_hook;    /* The original hook.  */
  52 static hook_type *exec_file_extra_hooks;        /* Array of additional
  53                                                    hooks.  */
  54 static int exec_file_hook_count = 0;            /* Size of array.  */
  55
  56 /* Binary file diddling handle for the core file.  */
  57
  58 bfd *core_bfd = NULL;
  59
  60 /* corelow.c target.  It is never NULL after GDB initialization.  */
  61
  62 struct target_ops *core_target;
  63 \f
  64
  65 /* Backward compatability with old way of specifying core files.  */
  66
  67 void
  68 core_file_command (char *filename, int from_tty)
  69 {
  70   dont_repeat ();               /* Either way, seems bogus.  */
  71
  72   gdb_assert (core_target != NULL);
  73
  74   if (!filename)
  75     (core_target->to_detach) (core_target, filename, from_tty);
  76   else
  77     (core_target->to_open) (filename, from_tty);
  78 }
  79 \f
  80
  81 /* If there are two or more functions that wish to hook into
  82    exec_file_command, this function will call all of the hook
  83    functions.  */
  84
  85 static void
  86 call_extra_exec_file_hooks (const char *filename)
  87 {
  88   int i;
  89
  90   for (i = 0; i < exec_file_hook_count; i++)
  91     (*exec_file_extra_hooks[i]) (filename);
  92 }
  93
  94 /* Call this to specify the hook for exec_file_command to call back.
  95    This is called from the x-window display code.  */
  96
  97 void
  98 specify_exec_file_hook (void (*hook) (const char *))
  99 {
 100   hook_type *new_array;
 101
 102   if (deprecated_exec_file_display_hook != NULL)
 103     {
 104       /* There's already a hook installed.  Arrange to have both it
 105          and the subsequent hooks called.  */
 106       if (exec_file_hook_count == 0)
 107         {
 108           /* If this is the first extra hook, initialize the hook
 109              array.  */
 110           exec_file_extra_hooks = XNEW (hook_type);
 111           exec_file_extra_hooks[0] = deprecated_exec_file_display_hook;
 112           deprecated_exec_file_display_hook = call_extra_exec_file_hooks;
 113           exec_file_hook_count = 1;
 114         }
 115
 116       /* Grow the hook array by one and add the new hook to the end.
 117          Yes, it's inefficient to grow it by one each time but since
 118          this is hardly ever called it's not a big deal.  */
 119       exec_file_hook_count++;
 120       new_array = (hook_type *)
 121         xrealloc (exec_file_extra_hooks,
 122                   exec_file_hook_count * sizeof (hook_type));
 123       exec_file_extra_hooks = new_array;
 124       exec_file_extra_hooks[exec_file_hook_count - 1] = hook;
 125     }
 126   else
 127     deprecated_exec_file_display_hook = hook;
 128 }
 129
 130 void
 131 reopen_exec_file (void)
 132 {
 133   char *filename;
 134   int res;
 135   struct stat st;
 136   struct cleanup *cleanups;
 137
 138   /* Don't do anything if there isn't an exec file.  */
 139   if (exec_bfd == NULL)
 140     return;
 141
 142   /* If the timestamp of the exec file has changed, reopen it.  */
 143   filename = xstrdup (bfd_get_filename (exec_bfd));
 144   cleanups = make_cleanup (xfree, filename);
 145   res = stat (filename, &st);
 146
 147   if (res == 0 && exec_bfd_mtime && exec_bfd_mtime != st.st_mtime)
 148     exec_file_attach (filename, 0);
 149   else
 150     /* If we accessed the file since last opening it, close it now;
 151        this stops GDB from holding the executable open after it
 152        exits.  */
 153     bfd_cache_close_all ();
 154
 155   do_cleanups (cleanups);
 156 }
 157 \f
 158 /* If we have both a core file and an exec file,
 159    print a warning if they don't go together.  */
 160
 161 void
 162 validate_files (void)
 163 {
 164   if (exec_bfd && core_bfd)
 165     {
 166       if (!core_file_matches_executable_p (core_bfd, exec_bfd))
 167         warning (_("core file may not match specified executable file."));
 168       else if (bfd_get_mtime (exec_bfd) > bfd_get_mtime (core_bfd))
 169         warning (_("exec file is newer than core file."));
 170     }
 171 }
 172
 173 /* Return the name of the executable file as a string.
 174    ERR nonzero means get error if there is none specified;
 175    otherwise return 0 in that case.  */
 176
 177 char *
 178 get_exec_file (int err)
 179 {
 180   if (exec_filename)
 181     return exec_filename;
 182   if (!err)
 183     return NULL;
 184
 185   error (_("No executable file specified.\n\
 186 Use the \"file\" or \"exec-file\" command."));
 187   return NULL;
 188 }
 189 \f
 190
 191 char *
 192 memory_error_message (enum target_xfer_status err,
 193                       struct gdbarch *gdbarch, CORE_ADDR memaddr)
 194 {
 195   switch (err)
 196     {
 197     case TARGET_XFER_E_IO:
 198       /* Actually, address between memaddr and memaddr + len was out of
 199          bounds.  */
 200       return xstrprintf (_("Cannot access memory at address %s"),
 201                          paddress (gdbarch, memaddr));
 202     case TARGET_XFER_UNAVAILABLE:
 203       return xstrprintf (_("Memory at address %s unavailable."),
 204                          paddress (gdbarch, memaddr));
 205     default:
 206       internal_error (__FILE__, __LINE__,
 207                       "unhandled target_xfer_status: %s (%s)",
 208                       target_xfer_status_to_string (err),
 209                       plongest (err));
 210     }
 211 }
 212
 213 /* Report a memory error by throwing a suitable exception.  */
 214
 215 void
 216 memory_error (enum target_xfer_status err, CORE_ADDR memaddr)
 217 {
 218   char *str;
 219   enum errors exception = GDB_NO_ERROR;
 220
 221   /* Build error string.  */
 222   str = memory_error_message (err, target_gdbarch (), memaddr);
 223   make_cleanup (xfree, str);
 224
 225   /* Choose the right error to throw.  */
 226   switch (err)
 227     {
 228     case TARGET_XFER_E_IO:
 229       exception = MEMORY_ERROR;
 230       break;
 231     case TARGET_XFER_UNAVAILABLE:
 232       exception = NOT_AVAILABLE_ERROR;
 233       break;
 234     }
 235
 236   /* Throw it.  */
 237   throw_error (exception, ("%s"), str);
 238 }
 239
 240 /* Helper function.  */
 241
 242 static void
 243 read_memory_object (enum target_object object, CORE_ADDR memaddr,
 244                     gdb_byte *myaddr, ssize_t len)
 245 {
 246   ULONGEST xfered = 0;
 247
 248   while (xfered < len)
 249     {
 250       enum target_xfer_status status;
 251       ULONGEST xfered_len;
 252
 253       status = target_xfer_partial (current_target.beneath,
 254                                     object, NULL,
 255                                     myaddr + xfered, NULL,
 256                                     memaddr + xfered, len - xfered,
 257                                     &xfered_len);
 258
 259       if (status != TARGET_XFER_OK)
 260         memory_error (status == TARGET_XFER_EOF ? TARGET_XFER_E_IO : status,
 261                       memaddr + xfered);
 262
 263       xfered += xfered_len;
 264       QUIT;
 265     }
 266 }
 267
 268 /* Same as target_read_memory, but report an error if can't read.  */
 269
 270 void
 271 read_memory (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len)
 272 {
 273   read_memory_object (TARGET_OBJECT_MEMORY, memaddr, myaddr, len);
 274 }
 275
 276 /* Same as target_read_stack, but report an error if can't read.  */
 277
 278 void
 279 read_stack (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len)
 280 {
 281   read_memory_object (TARGET_OBJECT_STACK_MEMORY, memaddr, myaddr, len);
 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   read_memory_object (TARGET_OBJECT_CODE_MEMORY, memaddr, myaddr, len);
 290 }
 291
 292 /* Read memory at MEMADDR of length LEN and put the contents in
 293    RETURN_VALUE.  Return 0 if MEMADDR couldn't be read and non-zero
 294    if successful.  */
 295
 296 int
 297 safe_read_memory_integer (CORE_ADDR memaddr, int len,
 298                           enum bfd_endian byte_order,
 299                           LONGEST *return_value)
 300 {
 301   gdb_byte buf[sizeof (LONGEST)];
 302
 303   if (target_read_memory (memaddr, buf, len))
 304     return 0;
 305
 306   *return_value = extract_signed_integer (buf, len, byte_order);
 307   return 1;
 308 }
 309
 310 /* Read memory at MEMADDR of length LEN and put the contents in
 311    RETURN_VALUE.  Return 0 if MEMADDR couldn't be read and non-zero
 312    if successful.  */
 313
 314 int
 315 safe_read_memory_unsigned_integer (CORE_ADDR memaddr, int len,
 316                                    enum bfd_endian byte_order,
 317                                    ULONGEST *return_value)
 318 {
 319   gdb_byte buf[sizeof (ULONGEST)];
 320
 321   if (target_read_memory (memaddr, buf, len))
 322     return 0;
 323
 324   *return_value = extract_unsigned_integer (buf, len, byte_order);
 325   return 1;
 326 }
 327
 328 LONGEST
 329 read_memory_integer (CORE_ADDR memaddr, int len,
 330                      enum bfd_endian byte_order)
 331 {
 332   gdb_byte buf[sizeof (LONGEST)];
 333
 334   read_memory (memaddr, buf, len);
 335   return extract_signed_integer (buf, len, byte_order);
 336 }
 337
 338 ULONGEST
 339 read_memory_unsigned_integer (CORE_ADDR memaddr, int len,
 340                               enum bfd_endian byte_order)
 341 {
 342   gdb_byte buf[sizeof (ULONGEST)];
 343
 344   read_memory (memaddr, buf, len);
 345   return extract_unsigned_integer (buf, len, byte_order);
 346 }
 347
 348 LONGEST
 349 read_code_integer (CORE_ADDR memaddr, int len,
 350                    enum bfd_endian byte_order)
 351 {
 352   gdb_byte buf[sizeof (LONGEST)];
 353
 354   read_code (memaddr, buf, len);
 355   return extract_signed_integer (buf, len, byte_order);
 356 }
 357
 358 ULONGEST
 359 read_code_unsigned_integer (CORE_ADDR memaddr, int len,
 360                             enum bfd_endian byte_order)
 361 {
 362   gdb_byte buf[sizeof (ULONGEST)];
 363
 364   read_code (memaddr, buf, len);
 365   return extract_unsigned_integer (buf, len, byte_order);
 366 }
 367
 368 void
 369 read_memory_string (CORE_ADDR memaddr, char *buffer, int max_len)
 370 {
 371   char *cp;
 372   int i;
 373   int cnt;
 374
 375   cp = buffer;
 376   while (1)
 377     {
 378       if (cp - buffer >= max_len)
 379         {
 380           buffer[max_len - 1] = '\0';
 381           break;
 382         }
 383       cnt = max_len - (cp - buffer);
 384       if (cnt > 8)
 385         cnt = 8;
 386       read_memory (memaddr + (int) (cp - buffer), (gdb_byte *) cp, cnt);
 387       for (i = 0; i < cnt && *cp; i++, cp++)
 388         ;                       /* null body */
 389
 390       if (i < cnt && !*cp)
 391         break;
 392     }
 393 }
 394
 395 CORE_ADDR
 396 read_memory_typed_address (CORE_ADDR addr, struct type *type)
 397 {
 398   gdb_byte *buf = (gdb_byte *) alloca (TYPE_LENGTH (type));
 399
 400   read_memory (addr, buf, TYPE_LENGTH (type));
 401   return extract_typed_address (buf, type);
 402 }
 403
 404 /* See gdbcore.h.  */
 405
 406 void
 407 write_memory (CORE_ADDR memaddr,
 408               const bfd_byte *myaddr, ssize_t len)
 409 {
 410   int status;
 411
 412   status = target_write_memory (memaddr, myaddr, len);
 413   if (status != 0)
 414     memory_error (TARGET_XFER_E_IO, memaddr);
 415 }
 416
 417 /* Same as write_memory, but notify 'memory_changed' observers.  */
 418
 419 void
 420 write_memory_with_notification (CORE_ADDR memaddr, const bfd_byte *myaddr,
 421                                 ssize_t len)
 422 {
 423   write_memory (memaddr, myaddr, len);
 424   observer_notify_memory_changed (current_inferior (), memaddr, len, myaddr);
 425 }
 426
 427 /* Store VALUE at ADDR in the inferior as a LEN-byte unsigned
 428    integer.  */
 429 void
 430 write_memory_unsigned_integer (CORE_ADDR addr, int len,
 431                                enum bfd_endian byte_order,
 432                                ULONGEST value)
 433 {
 434   gdb_byte *buf = (gdb_byte *) alloca (len);
 435
 436   store_unsigned_integer (buf, len, byte_order, value);
 437   write_memory (addr, buf, len);
 438 }
 439
 440 /* Store VALUE at ADDR in the inferior as a LEN-byte signed
 441    integer.  */
 442 void
 443 write_memory_signed_integer (CORE_ADDR addr, int len,
 444                              enum bfd_endian byte_order,
 445                              LONGEST value)
 446 {
 447   gdb_byte *buf = (gdb_byte *) alloca (len);
 448
 449   store_signed_integer (buf, len, byte_order, value);
 450   write_memory (addr, buf, len);
 451 }
 452 \f
 453 /* The current default bfd target.  Points to storage allocated for
 454    gnutarget_string.  */
 455 char *gnutarget;
 456
 457 /* Same thing, except it is "auto" not NULL for the default case.  */
 458 static char *gnutarget_string;
 459 static void
 460 show_gnutarget_string (struct ui_file *file, int from_tty,
 461                        struct cmd_list_element *c,
 462                        const char *value)
 463 {
 464   fprintf_filtered (file,
 465                     _("The current BFD target is \"%s\".\n"), value);
 466 }
 467
 468 static void set_gnutarget_command (char *, int,
 469                                    struct cmd_list_element *);
 470
 471 static void
 472 set_gnutarget_command (char *ignore, int from_tty,
 473                        struct cmd_list_element *c)
 474 {
 475   char *gend = gnutarget_string + strlen (gnutarget_string);
 476
 477   gend = remove_trailing_whitespace (gnutarget_string, gend);
 478   *gend = '\0';
 479
 480   if (strcmp (gnutarget_string, "auto") == 0)
 481     gnutarget = NULL;
 482   else
 483     gnutarget = gnutarget_string;
 484 }
 485
 486 /* A completion function for "set gnutarget".  */
 487
 488 static VEC (char_ptr) *
 489 complete_set_gnutarget (struct cmd_list_element *cmd,
 490                         const char *text, const char *word)
 491 {
 492   static const char **bfd_targets;
 493
 494   if (bfd_targets == NULL)
 495     {
 496       int last;
 497
 498       bfd_targets = bfd_target_list ();
 499       for (last = 0; bfd_targets[last] != NULL; ++last)
 500         ;
 501
 502       bfd_targets = XRESIZEVEC (const char *, bfd_targets, last + 2);
 503       bfd_targets[last] = "auto";
 504       bfd_targets[last + 1] = NULL;
 505     }
 506
 507   return complete_on_enum (bfd_targets, text, word);
 508 }
 509
 510 /* Set the gnutarget.  */
 511 void
 512 set_gnutarget (char *newtarget)
 513 {
 514   if (gnutarget_string != NULL)
 515     xfree (gnutarget_string);
 516   gnutarget_string = xstrdup (newtarget);
 517   set_gnutarget_command (NULL, 0, NULL);
 518 }
 519
 520 void
 521 _initialize_core (void)
 522 {
 523   struct cmd_list_element *c;
 524
 525   c = add_cmd ("core-file", class_files, core_file_command, _("\
 526 Use FILE as core dump for examining memory and registers.\n\
 527 No arg means have no core file.  This command has been superseded by the\n\
 528 `target core' and `detach' commands."), &cmdlist);
 529   set_cmd_completer (c, filename_completer);
 530
 531
 532   c = add_setshow_string_noescape_cmd ("gnutarget", class_files,
 533                                        &gnutarget_string, _("\
 534 Set the current BFD target."), _("\
 535 Show the current BFD target."), _("\
 536 Use `set gnutarget auto' to specify automatic detection."),
 537                                        set_gnutarget_command,
 538                                        show_gnutarget_string,
 539                                        &setlist, &showlist);
 540   set_cmd_completer (c, complete_set_gnutarget);
 541
 542   add_alias_cmd ("g", "gnutarget", class_files, 1, &setlist);
 543
 544   if (getenv ("GNUTARGET"))
 545     set_gnutarget (getenv ("GNUTARGET"));
 546   else
 547     set_gnutarget ("auto");
 548 }