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 (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 /* Same as target_read_memory, but report an error if can't read.  */
 241
 242 void
 243 read_memory (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len)
 244 {
 245   ULONGEST xfered = 0;
 246
 247   while (xfered < len)
 248     {
 249       enum target_xfer_status status;
 250       ULONGEST xfered_len;
 251
 252       status = target_xfer_partial (current_target.beneath,
 253                                     TARGET_OBJECT_MEMORY, NULL,
 254                                     myaddr + xfered, NULL,
 255                                     memaddr + xfered, len - xfered,
 256                                     &xfered_len);
 257
 258       if (status != TARGET_XFER_OK)
 259         memory_error (status == TARGET_XFER_EOF ? TARGET_XFER_E_IO : status,
 260                       memaddr + xfered);
 261
 262       xfered += xfered_len;
 263       QUIT;
 264     }
 265 }
 266
 267 /* Same as target_read_stack, but report an error if can't read.  */
 268
 269 void
 270 read_stack (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len)
 271 {
 272   int status;
 273
 274   status = target_read_stack (memaddr, myaddr, len);
 275   if (status != 0)
 276     memory_error (TARGET_XFER_E_IO, memaddr);
 277 }
 278
 279 /* Same as target_read_code, but report an error if can't read.  */
 280
 281 void
 282 read_code (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len)
 283 {
 284   int status;
 285
 286   status = target_read_code (memaddr, myaddr, len);
 287   if (status != 0)
 288     memory_error (TARGET_XFER_E_IO, memaddr);
 289 }
 290
 291 /* Read memory at MEMADDR of length LEN and put the contents in
 292    RETURN_VALUE.  Return 0 if MEMADDR couldn't be read and non-zero
 293    if successful.  */
 294
 295 int
 296 safe_read_memory_integer (CORE_ADDR memaddr, int len,
 297                           enum bfd_endian byte_order,
 298                           LONGEST *return_value)
 299 {
 300   gdb_byte buf[sizeof (LONGEST)];
 301
 302   if (target_read_memory (memaddr, buf, len))
 303     return 0;
 304
 305   *return_value = extract_signed_integer (buf, len, byte_order);
 306   return 1;
 307 }
 308
 309 /* Read memory at MEMADDR of length LEN and put the contents in
 310    RETURN_VALUE.  Return 0 if MEMADDR couldn't be read and non-zero
 311    if successful.  */
 312
 313 int
 314 safe_read_memory_unsigned_integer (CORE_ADDR memaddr, int len,
 315                                    enum bfd_endian byte_order,
 316                                    ULONGEST *return_value)
 317 {
 318   gdb_byte buf[sizeof (ULONGEST)];
 319
 320   if (target_read_memory (memaddr, buf, len))
 321     return 0;
 322
 323   *return_value = extract_unsigned_integer (buf, len, byte_order);
 324   return 1;
 325 }
 326
 327 LONGEST
 328 read_memory_integer (CORE_ADDR memaddr, int len,
 329                      enum bfd_endian byte_order)
 330 {
 331   gdb_byte buf[sizeof (LONGEST)];
 332
 333   read_memory (memaddr, buf, len);
 334   return extract_signed_integer (buf, len, byte_order);
 335 }
 336
 337 ULONGEST
 338 read_memory_unsigned_integer (CORE_ADDR memaddr, int len,
 339                               enum bfd_endian byte_order)
 340 {
 341   gdb_byte buf[sizeof (ULONGEST)];
 342
 343   read_memory (memaddr, buf, len);
 344   return extract_unsigned_integer (buf, len, byte_order);
 345 }
 346
 347 LONGEST
 348 read_code_integer (CORE_ADDR memaddr, int len,
 349                    enum bfd_endian byte_order)
 350 {
 351   gdb_byte buf[sizeof (LONGEST)];
 352
 353   read_code (memaddr, buf, len);
 354   return extract_signed_integer (buf, len, byte_order);
 355 }
 356
 357 ULONGEST
 358 read_code_unsigned_integer (CORE_ADDR memaddr, int len,
 359                             enum bfd_endian byte_order)
 360 {
 361   gdb_byte buf[sizeof (ULONGEST)];
 362
 363   read_code (memaddr, buf, len);
 364   return extract_unsigned_integer (buf, len, byte_order);
 365 }
 366
 367 void
 368 read_memory_string (CORE_ADDR memaddr, char *buffer, int max_len)
 369 {
 370   char *cp;
 371   int i;
 372   int cnt;
 373
 374   cp = buffer;
 375   while (1)
 376     {
 377       if (cp - buffer >= max_len)
 378         {
 379           buffer[max_len - 1] = '\0';
 380           break;
 381         }
 382       cnt = max_len - (cp - buffer);
 383       if (cnt > 8)
 384         cnt = 8;
 385       read_memory (memaddr + (int) (cp - buffer), (gdb_byte *) cp, cnt);
 386       for (i = 0; i < cnt && *cp; i++, cp++)
 387         ;                       /* null body */
 388
 389       if (i < cnt && !*cp)
 390         break;
 391     }
 392 }
 393
 394 CORE_ADDR
 395 read_memory_typed_address (CORE_ADDR addr, struct type *type)
 396 {
 397   gdb_byte *buf = (gdb_byte *) alloca (TYPE_LENGTH (type));
 398
 399   read_memory (addr, buf, TYPE_LENGTH (type));
 400   return extract_typed_address (buf, type);
 401 }
 402
 403 /* See gdbcore.h.  */
 404
 405 void
 406 write_memory (CORE_ADDR memaddr,
 407               const bfd_byte *myaddr, ssize_t len)
 408 {
 409   int status;
 410
 411   status = target_write_memory (memaddr, myaddr, len);
 412   if (status != 0)
 413     memory_error (TARGET_XFER_E_IO, memaddr);
 414 }
 415
 416 /* Same as write_memory, but notify 'memory_changed' observers.  */
 417
 418 void
 419 write_memory_with_notification (CORE_ADDR memaddr, const bfd_byte *myaddr,
 420                                 ssize_t len)
 421 {
 422   write_memory (memaddr, myaddr, len);
 423   observer_notify_memory_changed (current_inferior (), memaddr, len, myaddr);
 424 }
 425
 426 /* Store VALUE at ADDR in the inferior as a LEN-byte unsigned
 427    integer.  */
 428 void
 429 write_memory_unsigned_integer (CORE_ADDR addr, int len,
 430                                enum bfd_endian byte_order,
 431                                ULONGEST value)
 432 {
 433   gdb_byte *buf = (gdb_byte *) alloca (len);
 434
 435   store_unsigned_integer (buf, len, byte_order, value);
 436   write_memory (addr, buf, len);
 437 }
 438
 439 /* Store VALUE at ADDR in the inferior as a LEN-byte signed
 440    integer.  */
 441 void
 442 write_memory_signed_integer (CORE_ADDR addr, int len,
 443                              enum bfd_endian byte_order,
 444                              LONGEST value)
 445 {
 446   gdb_byte *buf = (gdb_byte *) alloca (len);
 447
 448   store_signed_integer (buf, len, byte_order, value);
 449   write_memory (addr, buf, len);
 450 }
 451 \f
 452 /* The current default bfd target.  Points to storage allocated for
 453    gnutarget_string.  */
 454 char *gnutarget;
 455
 456 /* Same thing, except it is "auto" not NULL for the default case.  */
 457 static char *gnutarget_string;
 458 static void
 459 show_gnutarget_string (struct ui_file *file, int from_tty,
 460                        struct cmd_list_element *c,
 461                        const char *value)
 462 {
 463   fprintf_filtered (file,
 464                     _("The current BFD target is \"%s\".\n"), value);
 465 }
 466
 467 static void set_gnutarget_command (char *, int,
 468                                    struct cmd_list_element *);
 469
 470 static void
 471 set_gnutarget_command (char *ignore, int from_tty,
 472                        struct cmd_list_element *c)
 473 {
 474   char *gend = gnutarget_string + strlen (gnutarget_string);
 475
 476   gend = remove_trailing_whitespace (gnutarget_string, gend);
 477   *gend = '\0';
 478
 479   if (strcmp (gnutarget_string, "auto") == 0)
 480     gnutarget = NULL;
 481   else
 482     gnutarget = gnutarget_string;
 483 }
 484
 485 /* A completion function for "set gnutarget".  */
 486
 487 static VEC (char_ptr) *
 488 complete_set_gnutarget (struct cmd_list_element *cmd,
 489                         const char *text, const char *word)
 490 {
 491   static const char **bfd_targets;
 492
 493   if (bfd_targets == NULL)
 494     {
 495       int last;
 496
 497       bfd_targets = bfd_target_list ();
 498       for (last = 0; bfd_targets[last] != NULL; ++last)
 499         ;
 500
 501       bfd_targets = XRESIZEVEC (const char *, bfd_targets, last + 2);
 502       bfd_targets[last] = "auto";
 503       bfd_targets[last + 1] = NULL;
 504     }
 505
 506   return complete_on_enum (bfd_targets, text, word);
 507 }
 508
 509 /* Set the gnutarget.  */
 510 void
 511 set_gnutarget (char *newtarget)
 512 {
 513   if (gnutarget_string != NULL)
 514     xfree (gnutarget_string);
 515   gnutarget_string = xstrdup (newtarget);
 516   set_gnutarget_command (NULL, 0, NULL);
 517 }
 518
 519 void
 520 _initialize_core (void)
 521 {
 522   struct cmd_list_element *c;
 523
 524   c = add_cmd ("core-file", class_files, core_file_command, _("\
 525 Use FILE as core dump for examining memory and registers.\n\
 526 No arg means have no core file.  This command has been superseded by the\n\
 527 `target core' and `detach' commands."), &cmdlist);
 528   set_cmd_completer (c, filename_completer);
 529
 530
 531   c = add_setshow_string_noescape_cmd ("gnutarget", class_files,
 532                                        &gnutarget_string, _("\
 533 Set the current BFD target."), _("\
 534 Show the current BFD target."), _("\
 535 Use `set gnutarget auto' to specify automatic detection."),
 536                                        set_gnutarget_command,
 537                                        show_gnutarget_string,
 538                                        &setlist, &showlist);
 539   set_cmd_completer (c, complete_set_gnutarget);
 540
 541   add_alias_cmd ("g", "gnutarget", class_files, 1, &setlist);
 542
 543   if (getenv ("GNUTARGET"))
 544     set_gnutarget (getenv ("GNUTARGET"));
 545   else
 546     set_gnutarget ("auto");
 547 }