gdb/corefile.c

   1 /* Core dump and executable file functions above target vector, for GDB.
   2
   3    Copyright (C) 1986-2015 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 = (hook_type *)
 111             xmalloc (sizeof (hook_type));
 112           exec_file_extra_hooks[0] = deprecated_exec_file_display_hook;
 113           deprecated_exec_file_display_hook = call_extra_exec_file_hooks;
 114           exec_file_hook_count = 1;
 115         }
 116
 117       /* Grow the hook array by one and add the new hook to the end.
 118          Yes, it's inefficient to grow it by one each time but since
 119          this is hardly ever called it's not a big deal.  */
 120       exec_file_hook_count++;
 121       new_array = (hook_type *)
 122         xrealloc (exec_file_extra_hooks,
 123                   exec_file_hook_count * sizeof (hook_type));
 124       exec_file_extra_hooks = new_array;
 125       exec_file_extra_hooks[exec_file_hook_count - 1] = hook;
 126     }
 127   else
 128     deprecated_exec_file_display_hook = hook;
 129 }
 130
 131 void
 132 reopen_exec_file (void)
 133 {
 134   char *filename;
 135   int res;
 136   struct stat st;
 137   struct cleanup *cleanups;
 138
 139   /* Don't do anything if there isn't an exec file.  */
 140   if (exec_bfd == NULL)
 141     return;
 142
 143   /* If the timestamp of the exec file has changed, reopen it.  */
 144   filename = xstrdup (bfd_get_filename (exec_bfd));
 145   cleanups = make_cleanup (xfree, filename);
 146   res = stat (filename, &st);
 147
 148   if (exec_bfd_mtime && exec_bfd_mtime != st.st_mtime)
 149     exec_file_attach (filename, 0);
 150   else
 151     /* If we accessed the file since last opening it, close it now;
 152        this stops GDB from holding the executable open after it
 153        exits.  */
 154     bfd_cache_close_all ();
 155
 156   do_cleanups (cleanups);
 157 }
 158 \f
 159 /* If we have both a core file and an exec file,
 160    print a warning if they don't go together.  */
 161
 162 void
 163 validate_files (void)
 164 {
 165   if (exec_bfd && core_bfd)
 166     {
 167       if (!core_file_matches_executable_p (core_bfd, exec_bfd))
 168         warning (_("core file may not match specified executable file."));
 169       else if (bfd_get_mtime (exec_bfd) > bfd_get_mtime (core_bfd))
 170         warning (_("exec file is newer than core file."));
 171     }
 172 }
 173
 174 /* Return the name of the executable file as a string.
 175    ERR nonzero means get error if there is none specified;
 176    otherwise return 0 in that case.  */
 177
 178 char *
 179 get_exec_file (int err)
 180 {
 181   if (exec_filename)
 182     return exec_filename;
 183   if (!err)
 184     return NULL;
 185
 186   error (_("No executable file specified.\n\
 187 Use the \"file\" or \"exec-file\" command."));
 188   return NULL;
 189 }
 190 \f
 191
 192 char *
 193 memory_error_message (enum target_xfer_status err,
 194                       struct gdbarch *gdbarch, CORE_ADDR memaddr)
 195 {
 196   switch (err)
 197     {
 198     case TARGET_XFER_E_IO:
 199       /* Actually, address between memaddr and memaddr + len was out of
 200          bounds.  */
 201       return xstrprintf (_("Cannot access memory at address %s"),
 202                          paddress (gdbarch, memaddr));
 203     case TARGET_XFER_UNAVAILABLE:
 204       return xstrprintf (_("Memory at address %s unavailable."),
 205                          paddress (gdbarch, memaddr));
 206     default:
 207       internal_error (__FILE__, __LINE__,
 208                       "unhandled target_xfer_status: %s (%s)",
 209                       target_xfer_status_to_string (err),
 210                       plongest (err));
 211     }
 212 }
 213
 214 /* Report a memory error by throwing a suitable exception.  */
 215
 216 void
 217 memory_error (enum target_xfer_status err, CORE_ADDR memaddr)
 218 {
 219   char *str;
 220   enum errors exception = GDB_NO_ERROR;
 221
 222   /* Build error string.  */
 223   str = memory_error_message (err, target_gdbarch (), memaddr);
 224   make_cleanup (xfree, str);
 225
 226   /* Choose the right error to throw.  */
 227   switch (err)
 228     {
 229     case TARGET_XFER_E_IO:
 230       exception = MEMORY_ERROR;
 231       break;
 232     case TARGET_XFER_UNAVAILABLE:
 233       exception = NOT_AVAILABLE_ERROR;
 234       break;
 235     }
 236
 237   /* Throw it.  */
 238   throw_error (exception, ("%s"), str);
 239 }
 240
 241 /* Same as target_read_memory, but report an error if can't read.  */
 242
 243 void
 244 read_memory (CORE_ADDR memaddr, 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                                     TARGET_OBJECT_MEMORY, 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_stack, but report an error if can't read.  */
 269
 270 void
 271 read_stack (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len)
 272 {
 273   int status;
 274
 275   status = target_read_stack (memaddr, myaddr, len);
 276   if (status != 0)
 277     memory_error (status, memaddr);
 278 }
 279
 280 /* Same as target_read_code, but report an error if can't read.  */
 281
 282 void
 283 read_code (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len)
 284 {
 285   int status;
 286
 287   status = target_read_code (memaddr, myaddr, len);
 288   if (status != 0)
 289     memory_error (status, memaddr);
 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 LONGEST
 311 read_memory_integer (CORE_ADDR memaddr, int len,
 312                      enum bfd_endian byte_order)
 313 {
 314   gdb_byte buf[sizeof (LONGEST)];
 315
 316   read_memory (memaddr, buf, len);
 317   return extract_signed_integer (buf, len, byte_order);
 318 }
 319
 320 ULONGEST
 321 read_memory_unsigned_integer (CORE_ADDR memaddr, int len,
 322                               enum bfd_endian byte_order)
 323 {
 324   gdb_byte buf[sizeof (ULONGEST)];
 325
 326   read_memory (memaddr, buf, len);
 327   return extract_unsigned_integer (buf, len, byte_order);
 328 }
 329
 330 LONGEST
 331 read_code_integer (CORE_ADDR memaddr, int len,
 332                    enum bfd_endian byte_order)
 333 {
 334   gdb_byte buf[sizeof (LONGEST)];
 335
 336   read_code (memaddr, buf, len);
 337   return extract_signed_integer (buf, len, byte_order);
 338 }
 339
 340 ULONGEST
 341 read_code_unsigned_integer (CORE_ADDR memaddr, int len,
 342                             enum bfd_endian byte_order)
 343 {
 344   gdb_byte buf[sizeof (ULONGEST)];
 345
 346   read_code (memaddr, buf, len);
 347   return extract_unsigned_integer (buf, len, byte_order);
 348 }
 349
 350 void
 351 read_memory_string (CORE_ADDR memaddr, char *buffer, int max_len)
 352 {
 353   char *cp;
 354   int i;
 355   int cnt;
 356
 357   cp = buffer;
 358   while (1)
 359     {
 360       if (cp - buffer >= max_len)
 361         {
 362           buffer[max_len - 1] = '\0';
 363           break;
 364         }
 365       cnt = max_len - (cp - buffer);
 366       if (cnt > 8)
 367         cnt = 8;
 368       read_memory (memaddr + (int) (cp - buffer), (gdb_byte *) cp, cnt);
 369       for (i = 0; i < cnt && *cp; i++, cp++)
 370         ;                       /* null body */
 371
 372       if (i < cnt && !*cp)
 373         break;
 374     }
 375 }
 376
 377 CORE_ADDR
 378 read_memory_typed_address (CORE_ADDR addr, struct type *type)
 379 {
 380   gdb_byte *buf = alloca (TYPE_LENGTH (type));
 381
 382   read_memory (addr, buf, TYPE_LENGTH (type));
 383   return extract_typed_address (buf, type);
 384 }
 385
 386 /* Same as target_write_memory, but report an error if can't
 387    write.  */
 388 void
 389 write_memory (CORE_ADDR memaddr,
 390               const bfd_byte *myaddr, ssize_t len)
 391 {
 392   int status;
 393
 394   status = target_write_memory (memaddr, myaddr, len);
 395   if (status != 0)
 396     memory_error (status, memaddr);
 397 }
 398
 399 /* Same as write_memory, but notify 'memory_changed' observers.  */
 400
 401 void
 402 write_memory_with_notification (CORE_ADDR memaddr, const bfd_byte *myaddr,
 403                                 ssize_t len)
 404 {
 405   write_memory (memaddr, myaddr, len);
 406   observer_notify_memory_changed (current_inferior (), memaddr, len, myaddr);
 407 }
 408
 409 /* Store VALUE at ADDR in the inferior as a LEN-byte unsigned
 410    integer.  */
 411 void
 412 write_memory_unsigned_integer (CORE_ADDR addr, int len,
 413                                enum bfd_endian byte_order,
 414                                ULONGEST value)
 415 {
 416   gdb_byte *buf = alloca (len);
 417
 418   store_unsigned_integer (buf, len, byte_order, value);
 419   write_memory (addr, buf, len);
 420 }
 421
 422 /* Store VALUE at ADDR in the inferior as a LEN-byte signed
 423    integer.  */
 424 void
 425 write_memory_signed_integer (CORE_ADDR addr, int len,
 426                              enum bfd_endian byte_order,
 427                              LONGEST value)
 428 {
 429   gdb_byte *buf = alloca (len);
 430
 431   store_signed_integer (buf, len, byte_order, value);
 432   write_memory (addr, buf, len);
 433 }
 434 \f
 435 /* The current default bfd target.  Points to storage allocated for
 436    gnutarget_string.  */
 437 char *gnutarget;
 438
 439 /* Same thing, except it is "auto" not NULL for the default case.  */
 440 static char *gnutarget_string;
 441 static void
 442 show_gnutarget_string (struct ui_file *file, int from_tty,
 443                        struct cmd_list_element *c,
 444                        const char *value)
 445 {
 446   fprintf_filtered (file,
 447                     _("The current BFD target is \"%s\".\n"), value);
 448 }
 449
 450 static void set_gnutarget_command (char *, int,
 451                                    struct cmd_list_element *);
 452
 453 static void
 454 set_gnutarget_command (char *ignore, int from_tty,
 455                        struct cmd_list_element *c)
 456 {
 457   char *gend = gnutarget_string + strlen (gnutarget_string);
 458
 459   gend = remove_trailing_whitespace (gnutarget_string, gend);
 460   *gend = '\0';
 461
 462   if (strcmp (gnutarget_string, "auto") == 0)
 463     gnutarget = NULL;
 464   else
 465     gnutarget = gnutarget_string;
 466 }
 467
 468 /* A completion function for "set gnutarget".  */
 469
 470 static VEC (char_ptr) *
 471 complete_set_gnutarget (struct cmd_list_element *cmd,
 472                         const char *text, const char *word)
 473 {
 474   static const char **bfd_targets;
 475
 476   if (bfd_targets == NULL)
 477     {
 478       int last;
 479
 480       bfd_targets = bfd_target_list ();
 481       for (last = 0; bfd_targets[last] != NULL; ++last)
 482         ;
 483
 484       bfd_targets = xrealloc (bfd_targets, (last + 2) * sizeof (const char **));
 485       bfd_targets[last] = "auto";
 486       bfd_targets[last + 1] = NULL;
 487     }
 488
 489   return complete_on_enum (bfd_targets, text, word);
 490 }
 491
 492 /* Set the gnutarget.  */
 493 void
 494 set_gnutarget (char *newtarget)
 495 {
 496   if (gnutarget_string != NULL)
 497     xfree (gnutarget_string);
 498   gnutarget_string = xstrdup (newtarget);
 499   set_gnutarget_command (NULL, 0, NULL);
 500 }
 501
 502 void
 503 _initialize_core (void)
 504 {
 505   struct cmd_list_element *c;
 506
 507   c = add_cmd ("core-file", class_files, core_file_command, _("\
 508 Use FILE as core dump for examining memory and registers.\n\
 509 No arg means have no core file.  This command has been superseded by the\n\
 510 `target core' and `detach' commands."), &cmdlist);
 511   set_cmd_completer (c, filename_completer);
 512
 513
 514   c = add_setshow_string_noescape_cmd ("gnutarget", class_files,
 515                                        &gnutarget_string, _("\
 516 Set the current BFD target."), _("\
 517 Show the current BFD target."), _("\
 518 Use `set gnutarget auto' to specify automatic detection."),
 519                                        set_gnutarget_command,
 520                                        show_gnutarget_string,
 521                                        &setlist, &showlist);
 522   set_cmd_completer (c, complete_set_gnutarget);
 523
 524   add_alias_cmd ("g", "gnutarget", class_files, 1, &setlist);
 525
 526   if (getenv ("GNUTARGET"))
 527     set_gnutarget (getenv ("GNUTARGET"));
 528   else
 529     set_gnutarget ("auto");
 530 }