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 LONGEST
 310 read_memory_integer (CORE_ADDR memaddr, int len,
 311                      enum bfd_endian byte_order)
 312 {
 313   gdb_byte buf[sizeof (LONGEST)];
 314
 315   read_memory (memaddr, buf, len);
 316   return extract_signed_integer (buf, len, byte_order);
 317 }
 318
 319 ULONGEST
 320 read_memory_unsigned_integer (CORE_ADDR memaddr, int len,
 321                               enum bfd_endian byte_order)
 322 {
 323   gdb_byte buf[sizeof (ULONGEST)];
 324
 325   read_memory (memaddr, buf, len);
 326   return extract_unsigned_integer (buf, len, byte_order);
 327 }
 328
 329 LONGEST
 330 read_code_integer (CORE_ADDR memaddr, int len,
 331                    enum bfd_endian byte_order)
 332 {
 333   gdb_byte buf[sizeof (LONGEST)];
 334
 335   read_code (memaddr, buf, len);
 336   return extract_signed_integer (buf, len, byte_order);
 337 }
 338
 339 ULONGEST
 340 read_code_unsigned_integer (CORE_ADDR memaddr, int len,
 341                             enum bfd_endian byte_order)
 342 {
 343   gdb_byte buf[sizeof (ULONGEST)];
 344
 345   read_code (memaddr, buf, len);
 346   return extract_unsigned_integer (buf, len, byte_order);
 347 }
 348
 349 void
 350 read_memory_string (CORE_ADDR memaddr, char *buffer, int max_len)
 351 {
 352   char *cp;
 353   int i;
 354   int cnt;
 355
 356   cp = buffer;
 357   while (1)
 358     {
 359       if (cp - buffer >= max_len)
 360         {
 361           buffer[max_len - 1] = '\0';
 362           break;
 363         }
 364       cnt = max_len - (cp - buffer);
 365       if (cnt > 8)
 366         cnt = 8;
 367       read_memory (memaddr + (int) (cp - buffer), (gdb_byte *) cp, cnt);
 368       for (i = 0; i < cnt && *cp; i++, cp++)
 369         ;                       /* null body */
 370
 371       if (i < cnt && !*cp)
 372         break;
 373     }
 374 }
 375
 376 CORE_ADDR
 377 read_memory_typed_address (CORE_ADDR addr, struct type *type)
 378 {
 379   gdb_byte *buf = (gdb_byte *) alloca (TYPE_LENGTH (type));
 380
 381   read_memory (addr, buf, TYPE_LENGTH (type));
 382   return extract_typed_address (buf, type);
 383 }
 384
 385 /* See gdbcore.h.  */
 386
 387 void
 388 write_memory (CORE_ADDR memaddr,
 389               const bfd_byte *myaddr, ssize_t len)
 390 {
 391   int status;
 392
 393   status = target_write_memory (memaddr, myaddr, len);
 394   if (status != 0)
 395     memory_error (TARGET_XFER_E_IO, memaddr);
 396 }
 397
 398 /* Same as write_memory, but notify 'memory_changed' observers.  */
 399
 400 void
 401 write_memory_with_notification (CORE_ADDR memaddr, const bfd_byte *myaddr,
 402                                 ssize_t len)
 403 {
 404   write_memory (memaddr, myaddr, len);
 405   observer_notify_memory_changed (current_inferior (), memaddr, len, myaddr);
 406 }
 407
 408 /* Store VALUE at ADDR in the inferior as a LEN-byte unsigned
 409    integer.  */
 410 void
 411 write_memory_unsigned_integer (CORE_ADDR addr, int len,
 412                                enum bfd_endian byte_order,
 413                                ULONGEST value)
 414 {
 415   gdb_byte *buf = (gdb_byte *) alloca (len);
 416
 417   store_unsigned_integer (buf, len, byte_order, value);
 418   write_memory (addr, buf, len);
 419 }
 420
 421 /* Store VALUE at ADDR in the inferior as a LEN-byte signed
 422    integer.  */
 423 void
 424 write_memory_signed_integer (CORE_ADDR addr, int len,
 425                              enum bfd_endian byte_order,
 426                              LONGEST value)
 427 {
 428   gdb_byte *buf = (gdb_byte *) alloca (len);
 429
 430   store_signed_integer (buf, len, byte_order, value);
 431   write_memory (addr, buf, len);
 432 }
 433 \f
 434 /* The current default bfd target.  Points to storage allocated for
 435    gnutarget_string.  */
 436 char *gnutarget;
 437
 438 /* Same thing, except it is "auto" not NULL for the default case.  */
 439 static char *gnutarget_string;
 440 static void
 441 show_gnutarget_string (struct ui_file *file, int from_tty,
 442                        struct cmd_list_element *c,
 443                        const char *value)
 444 {
 445   fprintf_filtered (file,
 446                     _("The current BFD target is \"%s\".\n"), value);
 447 }
 448
 449 static void set_gnutarget_command (char *, int,
 450                                    struct cmd_list_element *);
 451
 452 static void
 453 set_gnutarget_command (char *ignore, int from_tty,
 454                        struct cmd_list_element *c)
 455 {
 456   char *gend = gnutarget_string + strlen (gnutarget_string);
 457
 458   gend = remove_trailing_whitespace (gnutarget_string, gend);
 459   *gend = '\0';
 460
 461   if (strcmp (gnutarget_string, "auto") == 0)
 462     gnutarget = NULL;
 463   else
 464     gnutarget = gnutarget_string;
 465 }
 466
 467 /* A completion function for "set gnutarget".  */
 468
 469 static VEC (char_ptr) *
 470 complete_set_gnutarget (struct cmd_list_element *cmd,
 471                         const char *text, const char *word)
 472 {
 473   static const char **bfd_targets;
 474
 475   if (bfd_targets == NULL)
 476     {
 477       int last;
 478
 479       bfd_targets = bfd_target_list ();
 480       for (last = 0; bfd_targets[last] != NULL; ++last)
 481         ;
 482
 483       bfd_targets = XRESIZEVEC (const char *, bfd_targets, last + 2);
 484       bfd_targets[last] = "auto";
 485       bfd_targets[last + 1] = NULL;
 486     }
 487
 488   return complete_on_enum (bfd_targets, text, word);
 489 }
 490
 491 /* Set the gnutarget.  */
 492 void
 493 set_gnutarget (char *newtarget)
 494 {
 495   if (gnutarget_string != NULL)
 496     xfree (gnutarget_string);
 497   gnutarget_string = xstrdup (newtarget);
 498   set_gnutarget_command (NULL, 0, NULL);
 499 }
 500
 501 void
 502 _initialize_core (void)
 503 {
 504   struct cmd_list_element *c;
 505
 506   c = add_cmd ("core-file", class_files, core_file_command, _("\
 507 Use FILE as core dump for examining memory and registers.\n\
 508 No arg means have no core file.  This command has been superseded by the\n\
 509 `target core' and `detach' commands."), &cmdlist);
 510   set_cmd_completer (c, filename_completer);
 511
 512
 513   c = add_setshow_string_noescape_cmd ("gnutarget", class_files,
 514                                        &gnutarget_string, _("\
 515 Set the current BFD target."), _("\
 516 Show the current BFD target."), _("\
 517 Use `set gnutarget auto' to specify automatic detection."),
 518                                        set_gnutarget_command,
 519                                        show_gnutarget_string,
 520                                        &setlist, &showlist);
 521   set_cmd_completer (c, complete_set_gnutarget);
 522
 523   add_alias_cmd ("g", "gnutarget", class_files, 1, &setlist);
 524
 525   if (getenv ("GNUTARGET"))
 526     set_gnutarget (getenv ("GNUTARGET"));
 527   else
 528     set_gnutarget ("auto");
 529 }