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
   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   long mtime;
 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   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 #endif
 174 }
 175 \f
 176 /* If we have both a core file and an exec file,
 177    print a warning if they don't go together.  */
 178
 179 void
 180 validate_files (void)
 181 {
 182   if (exec_bfd && core_bfd)
 183     {
 184       if (!core_file_matches_executable_p (core_bfd, exec_bfd))
 185         warning (_("core file may not match specified executable file."));
 186       else if (bfd_get_mtime (exec_bfd) > bfd_get_mtime (core_bfd))
 187         warning (_("exec file is newer than core file."));
 188     }
 189 }
 190
 191 /* Return the name of the executable file as a string.
 192    ERR nonzero means get error if there is none specified;
 193    otherwise return 0 in that case.  */
 194
 195 char *
 196 get_exec_file (int err)
 197 {
 198   if (exec_bfd)
 199     return bfd_get_filename (exec_bfd);
 200   if (!err)
 201     return NULL;
 202
 203   error (_("No executable file specified.\n\
 204 Use the \"file\" or \"exec-file\" command."));
 205   return NULL;
 206 }
 207 \f
 208
 209 /* Report a memory error by throwing a MEMORY_ERROR error.  */
 210
 211 void
 212 memory_error (int status, CORE_ADDR memaddr)
 213 {
 214   if (status == EIO)
 215     /* Actually, address between memaddr and memaddr + len was out of
 216        bounds.  */
 217     throw_error (MEMORY_ERROR,
 218                  _("Cannot access memory at address %s"),
 219                  paddress (memaddr));
 220   else
 221     throw_error (MEMORY_ERROR,
 222                  _("Error accessing memory address %s: %s."),
 223                  paddress (memaddr),
 224                  safe_strerror (status));
 225 }
 226
 227 /* Same as target_read_memory, but report an error if can't read.  */
 228 void
 229 read_memory (CORE_ADDR memaddr, gdb_byte *myaddr, int len)
 230 {
 231   int status;
 232   status = target_read_memory (memaddr, myaddr, len);
 233   if (status != 0)
 234     memory_error (status, memaddr);
 235 }
 236
 237 /* Argument / return result struct for use with
 238    do_captured_read_memory_integer().  MEMADDR and LEN are filled in
 239    by gdb_read_memory_integer().  RESULT is the contents that were
 240    successfully read from MEMADDR of length LEN.  */
 241
 242 struct captured_read_memory_integer_arguments
 243 {
 244   CORE_ADDR memaddr;
 245   int len;
 246   LONGEST result;
 247 };
 248
 249 /* Helper function for gdb_read_memory_integer().  DATA must be a
 250    pointer to a captured_read_memory_integer_arguments struct.
 251    Return 1 if successful.  Note that the catch_errors() interface
 252    will return 0 if an error occurred while reading memory.  This
 253    choice of return code is so that we can distinguish between
 254    success and failure.  */
 255
 256 static int
 257 do_captured_read_memory_integer (void *data)
 258 {
 259   struct captured_read_memory_integer_arguments *args = (struct captured_read_memory_integer_arguments*) data;
 260   CORE_ADDR memaddr = args->memaddr;
 261   int len = args->len;
 262
 263   args->result = read_memory_integer (memaddr, len);
 264
 265   return 1;
 266 }
 267
 268 /* Read memory at MEMADDR of length LEN and put the contents in
 269    RETURN_VALUE.  Return 0 if MEMADDR couldn't be read and non-zero
 270    if successful.  */
 271
 272 int
 273 safe_read_memory_integer (CORE_ADDR memaddr, int len, LONGEST *return_value)
 274 {
 275   int status;
 276   struct captured_read_memory_integer_arguments args;
 277   args.memaddr = memaddr;
 278   args.len = len;
 279
 280   status = catch_errors (do_captured_read_memory_integer, &args,
 281                         "", RETURN_MASK_ALL);
 282   if (status)
 283     *return_value = args.result;
 284
 285   return status;
 286 }
 287
 288 LONGEST
 289 read_memory_integer (CORE_ADDR memaddr, int len)
 290 {
 291   gdb_byte buf[sizeof (LONGEST)];
 292
 293   read_memory (memaddr, buf, len);
 294   return extract_signed_integer (buf, len);
 295 }
 296
 297 ULONGEST
 298 read_memory_unsigned_integer (CORE_ADDR memaddr, int len)
 299 {
 300   gdb_byte buf[sizeof (ULONGEST)];
 301
 302   read_memory (memaddr, buf, len);
 303   return extract_unsigned_integer (buf, len);
 304 }
 305
 306 void
 307 read_memory_string (CORE_ADDR memaddr, char *buffer, int max_len)
 308 {
 309   char *cp;
 310   int i;
 311   int cnt;
 312
 313   cp = buffer;
 314   while (1)
 315     {
 316       if (cp - buffer >= max_len)
 317         {
 318           buffer[max_len - 1] = '\0';
 319           break;
 320         }
 321       cnt = max_len - (cp - buffer);
 322       if (cnt > 8)
 323         cnt = 8;
 324       read_memory (memaddr + (int) (cp - buffer), cp, cnt);
 325       for (i = 0; i < cnt && *cp; i++, cp++)
 326         ;                       /* null body */
 327
 328       if (i < cnt && !*cp)
 329         break;
 330     }
 331 }
 332
 333 CORE_ADDR
 334 read_memory_typed_address (CORE_ADDR addr, struct type *type)
 335 {
 336   gdb_byte *buf = alloca (TYPE_LENGTH (type));
 337   read_memory (addr, buf, TYPE_LENGTH (type));
 338   return extract_typed_address (buf, type);
 339 }
 340
 341 /* Same as target_write_memory, but report an error if can't write.  */
 342 void
 343 write_memory (CORE_ADDR memaddr, const bfd_byte *myaddr, int len)
 344 {
 345   int status;
 346   status = target_write_memory (memaddr, myaddr, len);
 347   if (status != 0)
 348     memory_error (status, memaddr);
 349 }
 350
 351 /* Store VALUE at ADDR in the inferior as a LEN-byte unsigned integer.  */
 352 void
 353 write_memory_unsigned_integer (CORE_ADDR addr, int len, ULONGEST value)
 354 {
 355   gdb_byte *buf = alloca (len);
 356   store_unsigned_integer (buf, len, value);
 357   write_memory (addr, buf, len);
 358 }
 359
 360 /* Store VALUE at ADDR in the inferior as a LEN-byte signed integer.  */
 361 void
 362 write_memory_signed_integer (CORE_ADDR addr, int len, LONGEST value)
 363 {
 364   gdb_byte *buf = alloca (len);
 365   store_signed_integer (buf, len, value);
 366   write_memory (addr, buf, len);
 367 }
 368
 369 \f
 370
 371 #if 0
 372 /* Enable after 4.12.  It is not tested.  */
 373
 374 /* Search code.  Targets can just make this their search function, or
 375    if the protocol has a less general search function, they can call this
 376    in the cases it can't handle.  */
 377 void
 378 generic_search (int len, char *data, char *mask, CORE_ADDR startaddr,
 379                 int increment, CORE_ADDR lorange, CORE_ADDR hirange,
 380                 CORE_ADDR *addr_found, char *data_found)
 381 {
 382   int i;
 383   CORE_ADDR curaddr = startaddr;
 384
 385   while (curaddr >= lorange && curaddr < hirange)
 386     {
 387       read_memory (curaddr, data_found, len);
 388       for (i = 0; i < len; ++i)
 389         if ((data_found[i] & mask[i]) != data[i])
 390           goto try_again;
 391       /* It matches.  */
 392       *addr_found = curaddr;
 393       return;
 394
 395     try_again:
 396       curaddr += increment;
 397     }
 398   *addr_found = (CORE_ADDR) 0;
 399   return;
 400 }
 401 #endif /* 0 */
 402 \f
 403 /* The current default bfd target.  Points to storage allocated for
 404    gnutarget_string.  */
 405 char *gnutarget;
 406
 407 /* Same thing, except it is "auto" not NULL for the default case.  */
 408 static char *gnutarget_string;
 409 static void
 410 show_gnutarget_string (struct ui_file *file, int from_tty,
 411                        struct cmd_list_element *c, const char *value)
 412 {
 413   fprintf_filtered (file, _("The current BFD target is \"%s\".\n"), value);
 414 }
 415
 416 static void set_gnutarget_command (char *, int, struct cmd_list_element *);
 417
 418 static void
 419 set_gnutarget_command (char *ignore, int from_tty, struct cmd_list_element *c)
 420 {
 421   if (strcmp (gnutarget_string, "auto") == 0)
 422     gnutarget = NULL;
 423   else
 424     gnutarget = gnutarget_string;
 425 }
 426
 427 /* Set the gnutarget.  */
 428 void
 429 set_gnutarget (char *newtarget)
 430 {
 431   if (gnutarget_string != NULL)
 432     xfree (gnutarget_string);
 433   gnutarget_string = savestring (newtarget, strlen (newtarget));
 434   set_gnutarget_command (NULL, 0, NULL);
 435 }
 436
 437 void
 438 _initialize_core (void)
 439 {
 440   struct cmd_list_element *c;
 441   c = add_cmd ("core-file", class_files, core_file_command, _("\
 442 Use FILE as core dump for examining memory and registers.\n\
 443 No arg means have no core file.  This command has been superseded by the\n\
 444 `target core' and `detach' commands."), &cmdlist);
 445   set_cmd_completer (c, filename_completer);
 446
 447
 448   add_setshow_string_noescape_cmd ("gnutarget", class_files,
 449                                    &gnutarget_string, _("\
 450 Set the current BFD target."), _("\
 451 Show the current BFD target."), _("\
 452 Use `set gnutarget auto' to specify automatic detection."),
 453                                    set_gnutarget_command,
 454                                    show_gnutarget_string,
 455                                    &setlist, &showlist);
 456
 457   if (getenv ("GNUTARGET"))
 458     set_gnutarget (getenv ("GNUTARGET"));
 459   else
 460     set_gnutarget ("auto");
 461 }