gdb/corefile.c

   1 /* Core dump and executable file functions above target vector, for GDB.
   2
   3    Copyright (C) 1986-2014 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 <string.h>
  22 #include <errno.h>
  23 #include <signal.h>
  24 #include <fcntl.h>
  25 #include "inferior.h"
  26 #include "symtab.h"
  27 #include "command.h"
  28 #include "gdbcmd.h"
  29 #include "bfd.h"
  30 #include "target.h"
  31 #include "gdbcore.h"
  32 #include "dis-asm.h"
  33 #include <sys/stat.h>
  34 #include "completer.h"
  35 #include "exceptions.h"
  36 #include "observer.h"
  37 #include "cli/cli-utils.h"
  38
  39 /* Local function declarations.  */
  40
  41 extern void _initialize_core (void);
  42 static void call_extra_exec_file_hooks (char *filename);
  43
  44 /* You can have any number of hooks for `exec_file_command' command to
  45    call.  If there's only one hook, it is set in exec_file_display
  46    hook.  If there are two or more hooks, they are set in
  47    exec_file_extra_hooks[], and deprecated_exec_file_display_hook is
  48    set to a function that calls all of them.  This extra complexity is
  49    needed to preserve compatibility with old code that assumed that
  50    only one hook could be set, and which called
  51    deprecated_exec_file_display_hook directly.  */
  52
  53 typedef void (*hook_type) (char *);
  54
  55 hook_type deprecated_exec_file_display_hook;    /* The original hook.  */
  56 static hook_type *exec_file_extra_hooks;        /* Array of additional
  57                                                    hooks.  */
  58 static int exec_file_hook_count = 0;            /* Size of array.  */
  59
  60 /* Binary file diddling handle for the core file.  */
  61
  62 bfd *core_bfd = NULL;
  63
  64 /* corelow.c target.  It is never NULL after GDB initialization.  */
  65
  66 struct target_ops *core_target;
  67 \f
  68
  69 /* Backward compatability with old way of specifying core files.  */
  70
  71 void
  72 core_file_command (char *filename, int from_tty)
  73 {
  74   dont_repeat ();               /* Either way, seems bogus.  */
  75
  76   gdb_assert (core_target != NULL);
  77
  78   if (!filename)
  79     (core_target->to_detach) (core_target, filename, from_tty);
  80   else
  81     (core_target->to_open) (filename, from_tty);
  82 }
  83 \f
  84
  85 /* If there are two or more functions that wish to hook into
  86    exec_file_command, this function will call all of the hook
  87    functions.  */
  88
  89 static void
  90 call_extra_exec_file_hooks (char *filename)
  91 {
  92   int i;
  93
  94   for (i = 0; i < exec_file_hook_count; i++)
  95     (*exec_file_extra_hooks[i]) (filename);
  96 }
  97
  98 /* Call this to specify the hook for exec_file_command to call back.
  99    This is called from the x-window display code.  */
 100
 101 void
 102 specify_exec_file_hook (void (*hook) (char *))
 103 {
 104   hook_type *new_array;
 105
 106   if (deprecated_exec_file_display_hook != NULL)
 107     {
 108       /* There's already a hook installed.  Arrange to have both it
 109          and the subsequent hooks called.  */
 110       if (exec_file_hook_count == 0)
 111         {
 112           /* If this is the first extra hook, initialize the hook
 113              array.  */
 114           exec_file_extra_hooks = (hook_type *)
 115             xmalloc (sizeof (hook_type));
 116           exec_file_extra_hooks[0] = deprecated_exec_file_display_hook;
 117           deprecated_exec_file_display_hook = call_extra_exec_file_hooks;
 118           exec_file_hook_count = 1;
 119         }
 120
 121       /* Grow the hook array by one and add the new hook to the end.
 122          Yes, it's inefficient to grow it by one each time but since
 123          this is hardly ever called it's not a big deal.  */
 124       exec_file_hook_count++;
 125       new_array = (hook_type *)
 126         xrealloc (exec_file_extra_hooks,
 127                   exec_file_hook_count * sizeof (hook_type));
 128       exec_file_extra_hooks = new_array;
 129       exec_file_extra_hooks[exec_file_hook_count - 1] = hook;
 130     }
 131   else
 132     deprecated_exec_file_display_hook = hook;
 133 }
 134
 135 void
 136 reopen_exec_file (void)
 137 {
 138   char *filename;
 139   int res;
 140   struct stat st;
 141   struct cleanup *cleanups;
 142
 143   /* Don't do anything if there isn't an exec file.  */
 144   if (exec_bfd == NULL)
 145     return;
 146
 147   /* If the timestamp of the exec file has changed, reopen it.  */
 148   filename = xstrdup (bfd_get_filename (exec_bfd));
 149   cleanups = make_cleanup (xfree, filename);
 150   res = stat (filename, &st);
 151
 152   if (exec_bfd_mtime && exec_bfd_mtime != st.st_mtime)
 153     exec_file_attach (filename, 0);
 154   else
 155     /* If we accessed the file since last opening it, close it now;
 156        this stops GDB from holding the executable open after it
 157        exits.  */
 158     bfd_cache_close_all ();
 159
 160   do_cleanups (cleanups);
 161 }
 162 \f
 163 /* If we have both a core file and an exec file,
 164    print a warning if they don't go together.  */
 165
 166 void
 167 validate_files (void)
 168 {
 169   if (exec_bfd && core_bfd)
 170     {
 171       if (!core_file_matches_executable_p (core_bfd, exec_bfd))
 172         warning (_("core file may not match specified executable file."));
 173       else if (bfd_get_mtime (exec_bfd) > bfd_get_mtime (core_bfd))
 174         warning (_("exec file is newer than core file."));
 175     }
 176 }
 177
 178 /* Return the name of the executable file as a string.
 179    ERR nonzero means get error if there is none specified;
 180    otherwise return 0 in that case.  */
 181
 182 char *
 183 get_exec_file (int err)
 184 {
 185   if (exec_filename)
 186     return exec_filename;
 187   if (!err)
 188     return NULL;
 189
 190   error (_("No executable file specified.\n\
 191 Use the \"file\" or \"exec-file\" command."));
 192   return NULL;
 193 }
 194 \f
 195
 196 char *
 197 memory_error_message (enum target_xfer_error err,
 198                       struct gdbarch *gdbarch, CORE_ADDR memaddr)
 199 {
 200   switch (err)
 201     {
 202     case TARGET_XFER_E_IO:
 203       /* Actually, address between memaddr and memaddr + len was out of
 204          bounds.  */
 205       return xstrprintf (_("Cannot access memory at address %s"),
 206                          paddress (gdbarch, memaddr));
 207     case TARGET_XFER_E_UNAVAILABLE:
 208       return xstrprintf (_("Memory at address %s unavailable."),
 209                          paddress (gdbarch, memaddr));
 210     default:
 211       internal_error (__FILE__, __LINE__,
 212                       "unhandled target_xfer_error: %s (%s)",
 213                       target_xfer_error_to_string (err),
 214                       plongest (err));
 215     }
 216 }
 217
 218 /* Report a memory error by throwing a suitable exception.  */
 219
 220 void
 221 memory_error (enum target_xfer_error err, CORE_ADDR memaddr)
 222 {
 223   char *str;
 224
 225   /* Build error string.  */
 226   str = memory_error_message (err, target_gdbarch (), memaddr);
 227   make_cleanup (xfree, str);
 228
 229   /* Choose the right error to throw.  */
 230   switch (err)
 231     {
 232     case TARGET_XFER_E_IO:
 233       err = MEMORY_ERROR;
 234       break;
 235     case TARGET_XFER_E_UNAVAILABLE:
 236       err = NOT_AVAILABLE_ERROR;
 237       break;
 238     }
 239
 240   /* Throw it.  */
 241   throw_error (err, ("%s"), str);
 242 }
 243
 244 /* Same as target_read_memory, but report an error if can't read.  */
 245
 246 void
 247 read_memory (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len)
 248 {
 249   LONGEST xfered = 0;
 250
 251   while (xfered < len)
 252     {
 253       LONGEST xfer = target_xfer_partial (current_target.beneath,
 254                                           TARGET_OBJECT_MEMORY, NULL,
 255                                           myaddr + xfered, NULL,
 256                                           memaddr + xfered, len - xfered);
 257
 258       if (xfer == 0)
 259         memory_error (TARGET_XFER_E_IO, memaddr + xfered);
 260       if (xfer < 0)
 261         memory_error (xfer, memaddr + xfered);
 262       xfered += xfer;
 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 (status, 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 (status, memaddr);
 289 }
 290
 291 /* Argument / return result struct for use with
 292    do_captured_read_memory_integer().  MEMADDR and LEN are filled in
 293    by gdb_read_memory_integer().  RESULT is the contents that were
 294    successfully read from MEMADDR of length LEN.  */
 295
 296 struct captured_read_memory_integer_arguments
 297 {
 298   CORE_ADDR memaddr;
 299   int len;
 300   enum bfd_endian byte_order;
 301   LONGEST result;
 302 };
 303
 304 /* Helper function for gdb_read_memory_integer().  DATA must be a
 305    pointer to a captured_read_memory_integer_arguments struct.
 306    Return 1 if successful.  Note that the catch_errors() interface
 307    will return 0 if an error occurred while reading memory.  This
 308    choice of return code is so that we can distinguish between
 309    success and failure.  */
 310
 311 static int
 312 do_captured_read_memory_integer (void *data)
 313 {
 314   struct captured_read_memory_integer_arguments *args
 315     = (struct captured_read_memory_integer_arguments*) data;
 316   CORE_ADDR memaddr = args->memaddr;
 317   int len = args->len;
 318   enum bfd_endian byte_order = args->byte_order;
 319
 320   args->result = read_memory_integer (memaddr, len, byte_order);
 321
 322   return 1;
 323 }
 324
 325 /* Read memory at MEMADDR of length LEN and put the contents in
 326    RETURN_VALUE.  Return 0 if MEMADDR couldn't be read and non-zero
 327    if successful.  */
 328
 329 int
 330 safe_read_memory_integer (CORE_ADDR memaddr, int len,
 331                           enum bfd_endian byte_order,
 332                           LONGEST *return_value)
 333 {
 334   int status;
 335   struct captured_read_memory_integer_arguments args;
 336
 337   args.memaddr = memaddr;
 338   args.len = len;
 339   args.byte_order = byte_order;
 340
 341   status = catch_errors (do_captured_read_memory_integer, &args,
 342                          "", RETURN_MASK_ALL);
 343   if (status)
 344     *return_value = args.result;
 345
 346   return status;
 347 }
 348
 349 LONGEST
 350 read_memory_integer (CORE_ADDR memaddr, int len,
 351                      enum bfd_endian byte_order)
 352 {
 353   gdb_byte buf[sizeof (LONGEST)];
 354
 355   read_memory (memaddr, buf, len);
 356   return extract_signed_integer (buf, len, byte_order);
 357 }
 358
 359 ULONGEST
 360 read_memory_unsigned_integer (CORE_ADDR memaddr, int len,
 361                               enum bfd_endian byte_order)
 362 {
 363   gdb_byte buf[sizeof (ULONGEST)];
 364
 365   read_memory (memaddr, buf, len);
 366   return extract_unsigned_integer (buf, len, byte_order);
 367 }
 368
 369 LONGEST
 370 read_code_integer (CORE_ADDR memaddr, int len,
 371                    enum bfd_endian byte_order)
 372 {
 373   gdb_byte buf[sizeof (LONGEST)];
 374
 375   read_code (memaddr, buf, len);
 376   return extract_signed_integer (buf, len, byte_order);
 377 }
 378
 379 ULONGEST
 380 read_code_unsigned_integer (CORE_ADDR memaddr, int len,
 381                             enum bfd_endian byte_order)
 382 {
 383   gdb_byte buf[sizeof (ULONGEST)];
 384
 385   read_code (memaddr, buf, len);
 386   return extract_unsigned_integer (buf, len, byte_order);
 387 }
 388
 389 void
 390 read_memory_string (CORE_ADDR memaddr, char *buffer, int max_len)
 391 {
 392   char *cp;
 393   int i;
 394   int cnt;
 395
 396   cp = buffer;
 397   while (1)
 398     {
 399       if (cp - buffer >= max_len)
 400         {
 401           buffer[max_len - 1] = '\0';
 402           break;
 403         }
 404       cnt = max_len - (cp - buffer);
 405       if (cnt > 8)
 406         cnt = 8;
 407       read_memory (memaddr + (int) (cp - buffer), (gdb_byte *) cp, cnt);
 408       for (i = 0; i < cnt && *cp; i++, cp++)
 409         ;                       /* null body */
 410
 411       if (i < cnt && !*cp)
 412         break;
 413     }
 414 }
 415
 416 CORE_ADDR
 417 read_memory_typed_address (CORE_ADDR addr, struct type *type)
 418 {
 419   gdb_byte *buf = alloca (TYPE_LENGTH (type));
 420
 421   read_memory (addr, buf, TYPE_LENGTH (type));
 422   return extract_typed_address (buf, type);
 423 }
 424
 425 /* Same as target_write_memory, but report an error if can't
 426    write.  */
 427 void
 428 write_memory (CORE_ADDR memaddr,
 429               const bfd_byte *myaddr, ssize_t len)
 430 {
 431   int status;
 432
 433   status = target_write_memory (memaddr, myaddr, len);
 434   if (status != 0)
 435     memory_error (status, memaddr);
 436 }
 437
 438 /* Same as write_memory, but notify 'memory_changed' observers.  */
 439
 440 void
 441 write_memory_with_notification (CORE_ADDR memaddr, const bfd_byte *myaddr,
 442                                 ssize_t len)
 443 {
 444   write_memory (memaddr, myaddr, len);
 445   observer_notify_memory_changed (current_inferior (), memaddr, len, myaddr);
 446 }
 447
 448 /* Store VALUE at ADDR in the inferior as a LEN-byte unsigned
 449    integer.  */
 450 void
 451 write_memory_unsigned_integer (CORE_ADDR addr, int len,
 452                                enum bfd_endian byte_order,
 453                                ULONGEST value)
 454 {
 455   gdb_byte *buf = alloca (len);
 456
 457   store_unsigned_integer (buf, len, byte_order, value);
 458   write_memory (addr, buf, len);
 459 }
 460
 461 /* Store VALUE at ADDR in the inferior as a LEN-byte signed
 462    integer.  */
 463 void
 464 write_memory_signed_integer (CORE_ADDR addr, int len,
 465                              enum bfd_endian byte_order,
 466                              LONGEST value)
 467 {
 468   gdb_byte *buf = alloca (len);
 469
 470   store_signed_integer (buf, len, byte_order, value);
 471   write_memory (addr, buf, len);
 472 }
 473 \f
 474 /* The current default bfd target.  Points to storage allocated for
 475    gnutarget_string.  */
 476 char *gnutarget;
 477
 478 /* Same thing, except it is "auto" not NULL for the default case.  */
 479 static char *gnutarget_string;
 480 static void
 481 show_gnutarget_string (struct ui_file *file, int from_tty,
 482                        struct cmd_list_element *c,
 483                        const char *value)
 484 {
 485   fprintf_filtered (file,
 486                     _("The current BFD target is \"%s\".\n"), value);
 487 }
 488
 489 static void set_gnutarget_command (char *, int,
 490                                    struct cmd_list_element *);
 491
 492 static void
 493 set_gnutarget_command (char *ignore, int from_tty,
 494                        struct cmd_list_element *c)
 495 {
 496   char *gend = gnutarget_string + strlen (gnutarget_string);
 497
 498   gend = remove_trailing_whitespace (gnutarget_string, gend);
 499   *gend = '\0';
 500
 501   if (strcmp (gnutarget_string, "auto") == 0)
 502     gnutarget = NULL;
 503   else
 504     gnutarget = gnutarget_string;
 505 }
 506
 507 /* A completion function for "set gnutarget".  */
 508
 509 static VEC (char_ptr) *
 510 complete_set_gnutarget (struct cmd_list_element *cmd,
 511                         const char *text, const char *word)
 512 {
 513   static const char **bfd_targets;
 514
 515   if (bfd_targets == NULL)
 516     {
 517       int last;
 518
 519       bfd_targets = bfd_target_list ();
 520       for (last = 0; bfd_targets[last] != NULL; ++last)
 521         ;
 522
 523       bfd_targets = xrealloc (bfd_targets, (last + 2) * sizeof (const char **));
 524       bfd_targets[last] = "auto";
 525       bfd_targets[last + 1] = NULL;
 526     }
 527
 528   return complete_on_enum (bfd_targets, text, word);
 529 }
 530
 531 /* Set the gnutarget.  */
 532 void
 533 set_gnutarget (char *newtarget)
 534 {
 535   if (gnutarget_string != NULL)
 536     xfree (gnutarget_string);
 537   gnutarget_string = xstrdup (newtarget);
 538   set_gnutarget_command (NULL, 0, NULL);
 539 }
 540
 541 void
 542 _initialize_core (void)
 543 {
 544   struct cmd_list_element *c;
 545
 546   c = add_cmd ("core-file", class_files, core_file_command, _("\
 547 Use FILE as core dump for examining memory and registers.\n\
 548 No arg means have no core file.  This command has been superseded by the\n\
 549 `target core' and `detach' commands."), &cmdlist);
 550   set_cmd_completer (c, filename_completer);
 551
 552
 553   c = add_setshow_string_noescape_cmd ("gnutarget", class_files,
 554                                        &gnutarget_string, _("\
 555 Set the current BFD target."), _("\
 556 Show the current BFD target."), _("\
 557 Use `set gnutarget auto' to specify automatic detection."),
 558                                        set_gnutarget_command,
 559                                        show_gnutarget_string,
 560                                        &setlist, &showlist);
 561   set_cmd_completer (c, complete_set_gnutarget);
 562
 563   add_alias_cmd ("g", "gnutarget", class_files, 1, &setlist);
 564
 565   if (getenv ("GNUTARGET"))
 566     set_gnutarget (getenv ("GNUTARGET"));
 567   else
 568     set_gnutarget ("auto");
 569 }