gdb/corefile.c

   1 /* Core dump and executable file functions above target vector, for GDB.
   2
   3    Copyright (C) 1986-2017 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 /* See common/common-inferior.h.  */
 174
 175 char *
 176 get_exec_file (int err)
 177 {
 178   if (exec_filename)
 179     return exec_filename;
 180   if (!err)
 181     return NULL;
 182
 183   error (_("No executable file specified.\n\
 184 Use the \"file\" or \"exec-file\" command."));
 185   return NULL;
 186 }
 187 \f
 188
 189 char *
 190 memory_error_message (enum target_xfer_status err,
 191                       struct gdbarch *gdbarch, CORE_ADDR memaddr)
 192 {
 193   switch (err)
 194     {
 195     case TARGET_XFER_E_IO:
 196       /* Actually, address between memaddr and memaddr + len was out of
 197          bounds.  */
 198       return xstrprintf (_("Cannot access memory at address %s"),
 199                          paddress (gdbarch, memaddr));
 200     case TARGET_XFER_UNAVAILABLE:
 201       return xstrprintf (_("Memory at address %s unavailable."),
 202                          paddress (gdbarch, memaddr));
 203     default:
 204       internal_error (__FILE__, __LINE__,
 205                       "unhandled target_xfer_status: %s (%s)",
 206                       target_xfer_status_to_string (err),
 207                       plongest (err));
 208     }
 209 }
 210
 211 /* Report a memory error by throwing a suitable exception.  */
 212
 213 void
 214 memory_error (enum target_xfer_status err, CORE_ADDR memaddr)
 215 {
 216   char *str;
 217   enum errors exception = GDB_NO_ERROR;
 218
 219   /* Build error string.  */
 220   str = memory_error_message (err, target_gdbarch (), memaddr);
 221   make_cleanup (xfree, str);
 222
 223   /* Choose the right error to throw.  */
 224   switch (err)
 225     {
 226     case TARGET_XFER_E_IO:
 227       exception = MEMORY_ERROR;
 228       break;
 229     case TARGET_XFER_UNAVAILABLE:
 230       exception = NOT_AVAILABLE_ERROR;
 231       break;
 232     }
 233
 234   /* Throw it.  */
 235   throw_error (exception, ("%s"), str);
 236 }
 237
 238 /* Helper function.  */
 239
 240 static void
 241 read_memory_object (enum target_object object, CORE_ADDR memaddr,
 242                     gdb_byte *myaddr, ssize_t len)
 243 {
 244   ULONGEST xfered = 0;
 245
 246   while (xfered < len)
 247     {
 248       enum target_xfer_status status;
 249       ULONGEST xfered_len;
 250
 251       status = target_xfer_partial (current_target.beneath,
 252                                     object, NULL,
 253                                     myaddr + xfered, NULL,
 254                                     memaddr + xfered, len - xfered,
 255                                     &xfered_len);
 256
 257       if (status != TARGET_XFER_OK)
 258         memory_error (status == TARGET_XFER_EOF ? TARGET_XFER_E_IO : status,
 259                       memaddr + xfered);
 260
 261       xfered += xfered_len;
 262       QUIT;
 263     }
 264 }
 265
 266 /* Same as target_read_memory, but report an error if can't read.  */
 267
 268 void
 269 read_memory (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len)
 270 {
 271   read_memory_object (TARGET_OBJECT_MEMORY, memaddr, myaddr, len);
 272 }
 273
 274 /* Same as target_read_stack, but report an error if can't read.  */
 275
 276 void
 277 read_stack (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len)
 278 {
 279   read_memory_object (TARGET_OBJECT_STACK_MEMORY, memaddr, myaddr, len);
 280 }
 281
 282 /* Same as target_read_code, but report an error if can't read.  */
 283
 284 void
 285 read_code (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len)
 286 {
 287   read_memory_object (TARGET_OBJECT_CODE_MEMORY, memaddr, myaddr, len);
 288 }
 289
 290 /* Read memory at MEMADDR of length LEN and put the contents in
 291    RETURN_VALUE.  Return 0 if MEMADDR couldn't be read and non-zero
 292    if successful.  */
 293
 294 int
 295 safe_read_memory_integer (CORE_ADDR memaddr, int len,
 296                           enum bfd_endian byte_order,
 297                           LONGEST *return_value)
 298 {
 299   gdb_byte buf[sizeof (LONGEST)];
 300
 301   if (target_read_memory (memaddr, buf, len))
 302     return 0;
 303
 304   *return_value = extract_signed_integer (buf, len, byte_order);
 305   return 1;
 306 }
 307
 308 /* Read memory at MEMADDR of length LEN and put the contents in
 309    RETURN_VALUE.  Return 0 if MEMADDR couldn't be read and non-zero
 310    if successful.  */
 311
 312 int
 313 safe_read_memory_unsigned_integer (CORE_ADDR memaddr, int len,
 314                                    enum bfd_endian byte_order,
 315                                    ULONGEST *return_value)
 316 {
 317   gdb_byte buf[sizeof (ULONGEST)];
 318
 319   if (target_read_memory (memaddr, buf, len))
 320     return 0;
 321
 322   *return_value = extract_unsigned_integer (buf, len, byte_order);
 323   return 1;
 324 }
 325
 326 LONGEST
 327 read_memory_integer (CORE_ADDR memaddr, int len,
 328                      enum bfd_endian byte_order)
 329 {
 330   gdb_byte buf[sizeof (LONGEST)];
 331
 332   read_memory (memaddr, buf, len);
 333   return extract_signed_integer (buf, len, byte_order);
 334 }
 335
 336 ULONGEST
 337 read_memory_unsigned_integer (CORE_ADDR memaddr, int len,
 338                               enum bfd_endian byte_order)
 339 {
 340   gdb_byte buf[sizeof (ULONGEST)];
 341
 342   read_memory (memaddr, buf, len);
 343   return extract_unsigned_integer (buf, len, byte_order);
 344 }
 345
 346 LONGEST
 347 read_code_integer (CORE_ADDR memaddr, int len,
 348                    enum bfd_endian byte_order)
 349 {
 350   gdb_byte buf[sizeof (LONGEST)];
 351
 352   read_code (memaddr, buf, len);
 353   return extract_signed_integer (buf, len, byte_order);
 354 }
 355
 356 ULONGEST
 357 read_code_unsigned_integer (CORE_ADDR memaddr, int len,
 358                             enum bfd_endian byte_order)
 359 {
 360   gdb_byte buf[sizeof (ULONGEST)];
 361
 362   read_code (memaddr, buf, len);
 363   return extract_unsigned_integer (buf, len, byte_order);
 364 }
 365
 366 void
 367 read_memory_string (CORE_ADDR memaddr, char *buffer, int max_len)
 368 {
 369   char *cp;
 370   int i;
 371   int cnt;
 372
 373   cp = buffer;
 374   while (1)
 375     {
 376       if (cp - buffer >= max_len)
 377         {
 378           buffer[max_len - 1] = '\0';
 379           break;
 380         }
 381       cnt = max_len - (cp - buffer);
 382       if (cnt > 8)
 383         cnt = 8;
 384       read_memory (memaddr + (int) (cp - buffer), (gdb_byte *) cp, cnt);
 385       for (i = 0; i < cnt && *cp; i++, cp++)
 386         ;                       /* null body */
 387
 388       if (i < cnt && !*cp)
 389         break;
 390     }
 391 }
 392
 393 CORE_ADDR
 394 read_memory_typed_address (CORE_ADDR addr, struct type *type)
 395 {
 396   gdb_byte *buf = (gdb_byte *) alloca (TYPE_LENGTH (type));
 397
 398   read_memory (addr, buf, TYPE_LENGTH (type));
 399   return extract_typed_address (buf, type);
 400 }
 401
 402 /* See gdbcore.h.  */
 403
 404 void
 405 write_memory (CORE_ADDR memaddr,
 406               const bfd_byte *myaddr, ssize_t len)
 407 {
 408   int status;
 409
 410   status = target_write_memory (memaddr, myaddr, len);
 411   if (status != 0)
 412     memory_error (TARGET_XFER_E_IO, memaddr);
 413 }
 414
 415 /* Same as write_memory, but notify 'memory_changed' observers.  */
 416
 417 void
 418 write_memory_with_notification (CORE_ADDR memaddr, const bfd_byte *myaddr,
 419                                 ssize_t len)
 420 {
 421   write_memory (memaddr, myaddr, len);
 422   observer_notify_memory_changed (current_inferior (), memaddr, len, myaddr);
 423 }
 424
 425 /* Store VALUE at ADDR in the inferior as a LEN-byte unsigned
 426    integer.  */
 427 void
 428 write_memory_unsigned_integer (CORE_ADDR addr, int len,
 429                                enum bfd_endian byte_order,
 430                                ULONGEST value)
 431 {
 432   gdb_byte *buf = (gdb_byte *) alloca (len);
 433
 434   store_unsigned_integer (buf, len, byte_order, value);
 435   write_memory (addr, buf, len);
 436 }
 437
 438 /* Store VALUE at ADDR in the inferior as a LEN-byte signed
 439    integer.  */
 440 void
 441 write_memory_signed_integer (CORE_ADDR addr, int len,
 442                              enum bfd_endian byte_order,
 443                              LONGEST value)
 444 {
 445   gdb_byte *buf = (gdb_byte *) alloca (len);
 446
 447   store_signed_integer (buf, len, byte_order, value);
 448   write_memory (addr, buf, len);
 449 }
 450 \f
 451 /* The current default bfd target.  Points to storage allocated for
 452    gnutarget_string.  */
 453 char *gnutarget;
 454
 455 /* Same thing, except it is "auto" not NULL for the default case.  */
 456 static char *gnutarget_string;
 457 static void
 458 show_gnutarget_string (struct ui_file *file, int from_tty,
 459                        struct cmd_list_element *c,
 460                        const char *value)
 461 {
 462   fprintf_filtered (file,
 463                     _("The current BFD target is \"%s\".\n"), value);
 464 }
 465
 466 static void set_gnutarget_command (char *, int,
 467                                    struct cmd_list_element *);
 468
 469 static void
 470 set_gnutarget_command (char *ignore, int from_tty,
 471                        struct cmd_list_element *c)
 472 {
 473   char *gend = gnutarget_string + strlen (gnutarget_string);
 474
 475   gend = remove_trailing_whitespace (gnutarget_string, gend);
 476   *gend = '\0';
 477
 478   if (strcmp (gnutarget_string, "auto") == 0)
 479     gnutarget = NULL;
 480   else
 481     gnutarget = gnutarget_string;
 482 }
 483
 484 /* A completion function for "set gnutarget".  */
 485
 486 static void
 487 complete_set_gnutarget (struct cmd_list_element *cmd,
 488                         completion_tracker &tracker,
 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   complete_on_enum (tracker, bfd_targets, text, word);
 507 }
 508
 509 /* Set the gnutarget.  */
 510 void
 511 set_gnutarget (const 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 }