gdb/corefile.c

   1 /* Core dump and executable file functions above target vector, for GDB.
   2
   3    Copyright (C) 1986, 1987, 1989, 1991, 1992, 1993, 1994, 1996, 1997, 1998,
   4    1999, 2000, 2001, 2003, 2006, 2007, 2008, 2009, 2010
   5    Free Software Foundation, Inc.
   6
   7    This file is part of GDB.
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  21
  22 #include "defs.h"
  23 #include "gdb_string.h"
  24 #include <errno.h>
  25 #include <signal.h>
  26 #include <fcntl.h>
  27 #include "inferior.h"
  28 #include "symtab.h"
  29 #include "command.h"
  30 #include "gdbcmd.h"
  31 #include "bfd.h"
  32 #include "target.h"
  33 #include "gdbcore.h"
  34 #include "dis-asm.h"
  35 #include "gdb_stat.h"
  36 #include "completer.h"
  37 #include "exceptions.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 hooks */
  57 static int exec_file_hook_count = 0;    /* size of array */
  58
  59 /* Binary file diddling handle for the core file.  */
  60
  61 bfd *core_bfd = NULL;
  62 \f
  63
  64 /* Backward compatability with old way of specifying core files.  */
  65
  66 void
  67 core_file_command (char *filename, int from_tty)
  68 {
  69   struct target_ops *t;
  70
  71   dont_repeat ();               /* Either way, seems bogus. */
  72
  73   t = find_core_target ();
  74   if (t == NULL)
  75     error (_("GDB can't read core files on this machine."));
  76
  77   if (!filename)
  78     (t->to_detach) (t, filename, from_tty);
  79   else
  80     (t->to_open) (filename, from_tty);
  81 }
  82 \f
  83
  84 /* If there are two or more functions that wish to hook into
  85    exec_file_command, this function will call all of the hook
  86    functions.  */
  87
  88 static void
  89 call_extra_exec_file_hooks (char *filename)
  90 {
  91   int i;
  92
  93   for (i = 0; i < exec_file_hook_count; i++)
  94     (*exec_file_extra_hooks[i]) (filename);
  95 }
  96
  97 /* Call this to specify the hook for exec_file_command to call back.
  98    This is called from the x-window display code.  */
  99
 100 void
 101 specify_exec_file_hook (void (*hook) (char *))
 102 {
 103   hook_type *new_array;
 104
 105   if (deprecated_exec_file_display_hook != NULL)
 106     {
 107       /* There's already a hook installed.  Arrange to have both it
 108        * and the subsequent hooks called. */
 109       if (exec_file_hook_count == 0)
 110         {
 111           /* If this is the first extra hook, initialize the hook array.  */
 112           exec_file_extra_hooks = (hook_type *) xmalloc (sizeof (hook_type));
 113           exec_file_extra_hooks[0] = deprecated_exec_file_display_hook;
 114           deprecated_exec_file_display_hook = call_extra_exec_file_hooks;
 115           exec_file_hook_count = 1;
 116         }
 117
 118       /* Grow the hook array by one and add the new hook to the end.
 119          Yes, it's inefficient to grow it by one each time but since
 120          this is hardly ever called it's not a big deal.  */
 121       exec_file_hook_count++;
 122       new_array =
 123         (hook_type *) xrealloc (exec_file_extra_hooks,
 124                                 exec_file_hook_count * sizeof (hook_type));
 125       exec_file_extra_hooks = new_array;
 126       exec_file_extra_hooks[exec_file_hook_count - 1] = hook;
 127     }
 128   else
 129     deprecated_exec_file_display_hook = hook;
 130 }
 131
 132 /* The exec file must be closed before running an inferior.
 133    If it is needed again after the inferior dies, it must
 134    be reopened.  */
 135
 136 void
 137 close_exec_file (void)
 138 {
 139 #if 0                           /* FIXME */
 140   if (exec_bfd)
 141     bfd_tempclose (exec_bfd);
 142 #endif
 143 }
 144
 145 void
 146 reopen_exec_file (void)
 147 {
 148 #if 0                           /* FIXME */
 149   if (exec_bfd)
 150     bfd_reopen (exec_bfd);
 151 #else
 152   char *filename;
 153   int res;
 154   struct stat st;
 155   struct cleanup *cleanups;
 156
 157   /* Don't do anything if there isn't an exec file. */
 158   if (exec_bfd == NULL)
 159     return;
 160
 161   /* If the timestamp of the exec file has changed, reopen it. */
 162   filename = xstrdup (bfd_get_filename (exec_bfd));
 163   cleanups = make_cleanup (xfree, filename);
 164   res = stat (filename, &st);
 165
 166   if (exec_bfd_mtime && exec_bfd_mtime != st.st_mtime)
 167     exec_file_attach (filename, 0);
 168   else
 169     /* If we accessed the file since last opening it, close it now;
 170        this stops GDB from holding the executable open after it
 171        exits.  */
 172     bfd_cache_close_all ();
 173
 174   do_cleanups (cleanups);
 175 #endif
 176 }
 177 \f
 178 /* If we have both a core file and an exec file,
 179    print a warning if they don't go together.  */
 180
 181 void
 182 validate_files (void)
 183 {
 184   if (exec_bfd && core_bfd)
 185     {
 186       if (!core_file_matches_executable_p (core_bfd, exec_bfd))
 187         warning (_("core file may not match specified executable file."));
 188       else if (bfd_get_mtime (exec_bfd) > bfd_get_mtime (core_bfd))
 189         warning (_("exec file is newer than core file."));
 190     }
 191 }
 192
 193 /* Return the name of the executable file as a string.
 194    ERR nonzero means get error if there is none specified;
 195    otherwise return 0 in that case.  */
 196
 197 char *
 198 get_exec_file (int err)
 199 {
 200   if (exec_bfd)
 201     return bfd_get_filename (exec_bfd);
 202   if (!err)
 203     return NULL;
 204
 205   error (_("No executable file specified.\n\
 206 Use the \"file\" or \"exec-file\" command."));
 207   return NULL;
 208 }
 209 \f
 210
 211 /* Report a memory error by throwing a MEMORY_ERROR error.  */
 212
 213 void
 214 memory_error (int status, CORE_ADDR memaddr)
 215 {
 216   if (status == EIO)
 217     /* Actually, address between memaddr and memaddr + len was out of
 218        bounds.  */
 219     throw_error (MEMORY_ERROR,
 220                  _("Cannot access memory at address %s"),
 221                  paddress (target_gdbarch, memaddr));
 222   else
 223     throw_error (MEMORY_ERROR,
 224                  _("Error accessing memory address %s: %s."),
 225                  paddress (target_gdbarch, memaddr),
 226                  safe_strerror (status));
 227 }
 228
 229 /* Same as target_read_memory, but report an error if can't read.  */
 230
 231 void
 232 read_memory (CORE_ADDR memaddr, gdb_byte *myaddr, int len)
 233 {
 234   int status;
 235   status = target_read_memory (memaddr, myaddr, len);
 236   if (status != 0)
 237     memory_error (status, memaddr);
 238 }
 239
 240 /* Same as target_read_stack, but report an error if can't read.  */
 241
 242 void
 243 read_stack (CORE_ADDR memaddr, gdb_byte *myaddr, int len)
 244 {
 245   int status;
 246   status = target_read_stack (memaddr, myaddr, len);
 247   if (status != 0)
 248     memory_error (status, memaddr);
 249 }
 250
 251 /* Argument / return result struct for use with
 252    do_captured_read_memory_integer().  MEMADDR and LEN are filled in
 253    by gdb_read_memory_integer().  RESULT is the contents that were
 254    successfully read from MEMADDR of length LEN.  */
 255
 256 struct captured_read_memory_integer_arguments
 257 {
 258   CORE_ADDR memaddr;
 259   int len;
 260   enum bfd_endian byte_order;
 261   LONGEST result;
 262 };
 263
 264 /* Helper function for gdb_read_memory_integer().  DATA must be a
 265    pointer to a captured_read_memory_integer_arguments struct.
 266    Return 1 if successful.  Note that the catch_errors() interface
 267    will return 0 if an error occurred while reading memory.  This
 268    choice of return code is so that we can distinguish between
 269    success and failure.  */
 270
 271 static int
 272 do_captured_read_memory_integer (void *data)
 273 {
 274   struct captured_read_memory_integer_arguments *args = (struct captured_read_memory_integer_arguments*) data;
 275   CORE_ADDR memaddr = args->memaddr;
 276   int len = args->len;
 277   enum bfd_endian byte_order = args->byte_order;
 278
 279   args->result = read_memory_integer (memaddr, len, byte_order);
 280
 281   return 1;
 282 }
 283
 284 /* Read memory at MEMADDR of length LEN and put the contents in
 285    RETURN_VALUE.  Return 0 if MEMADDR couldn't be read and non-zero
 286    if successful.  */
 287
 288 int
 289 safe_read_memory_integer (CORE_ADDR memaddr, int len, enum bfd_endian byte_order,
 290                           LONGEST *return_value)
 291 {
 292   int status;
 293   struct captured_read_memory_integer_arguments args;
 294   args.memaddr = memaddr;
 295   args.len = len;
 296   args.byte_order = byte_order;
 297
 298   status = catch_errors (do_captured_read_memory_integer, &args,
 299                         "", RETURN_MASK_ALL);
 300   if (status)
 301     *return_value = args.result;
 302
 303   return status;
 304 }
 305
 306 LONGEST
 307 read_memory_integer (CORE_ADDR memaddr, int len, enum bfd_endian byte_order)
 308 {
 309   gdb_byte buf[sizeof (LONGEST)];
 310
 311   read_memory (memaddr, buf, len);
 312   return extract_signed_integer (buf, len, byte_order);
 313 }
 314
 315 ULONGEST
 316 read_memory_unsigned_integer (CORE_ADDR memaddr, int len, enum bfd_endian byte_order)
 317 {
 318   gdb_byte buf[sizeof (ULONGEST)];
 319
 320   read_memory (memaddr, buf, len);
 321   return extract_unsigned_integer (buf, len, byte_order);
 322 }
 323
 324 void
 325 read_memory_string (CORE_ADDR memaddr, char *buffer, int max_len)
 326 {
 327   char *cp;
 328   int i;
 329   int cnt;
 330
 331   cp = buffer;
 332   while (1)
 333     {
 334       if (cp - buffer >= max_len)
 335         {
 336           buffer[max_len - 1] = '\0';
 337           break;
 338         }
 339       cnt = max_len - (cp - buffer);
 340       if (cnt > 8)
 341         cnt = 8;
 342       read_memory (memaddr + (int) (cp - buffer), cp, cnt);
 343       for (i = 0; i < cnt && *cp; i++, cp++)
 344         ;                       /* null body */
 345
 346       if (i < cnt && !*cp)
 347         break;
 348     }
 349 }
 350
 351 CORE_ADDR
 352 read_memory_typed_address (CORE_ADDR addr, struct type *type)
 353 {
 354   gdb_byte *buf = alloca (TYPE_LENGTH (type));
 355   read_memory (addr, buf, TYPE_LENGTH (type));
 356   return extract_typed_address (buf, type);
 357 }
 358
 359 /* Same as target_write_memory, but report an error if can't write.  */
 360 void
 361 write_memory (CORE_ADDR memaddr, const bfd_byte *myaddr, int len)
 362 {
 363   int status;
 364   status = target_write_memory (memaddr, myaddr, len);
 365   if (status != 0)
 366     memory_error (status, memaddr);
 367 }
 368
 369 /* Store VALUE at ADDR in the inferior as a LEN-byte unsigned integer.  */
 370 void
 371 write_memory_unsigned_integer (CORE_ADDR addr, int len, enum bfd_endian byte_order,
 372                                ULONGEST value)
 373 {
 374   gdb_byte *buf = alloca (len);
 375   store_unsigned_integer (buf, len, byte_order, value);
 376   write_memory (addr, buf, len);
 377 }
 378
 379 /* Store VALUE at ADDR in the inferior as a LEN-byte signed integer.  */
 380 void
 381 write_memory_signed_integer (CORE_ADDR addr, int len, enum bfd_endian byte_order,
 382                              LONGEST value)
 383 {
 384   gdb_byte *buf = alloca (len);
 385   store_signed_integer (buf, len, byte_order, value);
 386   write_memory (addr, buf, len);
 387 }
 388 \f
 389 /* The current default bfd target.  Points to storage allocated for
 390    gnutarget_string.  */
 391 char *gnutarget;
 392
 393 /* Same thing, except it is "auto" not NULL for the default case.  */
 394 static char *gnutarget_string;
 395 static void
 396 show_gnutarget_string (struct ui_file *file, int from_tty,
 397                        struct cmd_list_element *c, const char *value)
 398 {
 399   fprintf_filtered (file, _("The current BFD target is \"%s\".\n"), value);
 400 }
 401
 402 static void set_gnutarget_command (char *, int, struct cmd_list_element *);
 403
 404 static void
 405 set_gnutarget_command (char *ignore, int from_tty, struct cmd_list_element *c)
 406 {
 407   if (strcmp (gnutarget_string, "auto") == 0)
 408     gnutarget = NULL;
 409   else
 410     gnutarget = gnutarget_string;
 411 }
 412
 413 /* Set the gnutarget.  */
 414 void
 415 set_gnutarget (char *newtarget)
 416 {
 417   if (gnutarget_string != NULL)
 418     xfree (gnutarget_string);
 419   gnutarget_string = xstrdup (newtarget);
 420   set_gnutarget_command (NULL, 0, NULL);
 421 }
 422
 423 void
 424 _initialize_core (void)
 425 {
 426   struct cmd_list_element *c;
 427   c = add_cmd ("core-file", class_files, core_file_command, _("\
 428 Use FILE as core dump for examining memory and registers.\n\
 429 No arg means have no core file.  This command has been superseded by the\n\
 430 `target core' and `detach' commands."), &cmdlist);
 431   set_cmd_completer (c, filename_completer);
 432
 433
 434   add_setshow_string_noescape_cmd ("gnutarget", class_files,
 435                                    &gnutarget_string, _("\
 436 Set the current BFD target."), _("\
 437 Show the current BFD target."), _("\
 438 Use `set gnutarget auto' to specify automatic detection."),
 439                                    set_gnutarget_command,
 440                                    show_gnutarget_string,
 441                                    &setlist, &showlist);
 442
 443   if (getenv ("GNUTARGET"))
 444     set_gnutarget (getenv ("GNUTARGET"));
 445   else
 446     set_gnutarget ("auto");
 447 }