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   long mtime;
 156   struct cleanup *cleanups;
 157
 158   /* Don't do anything if there isn't an exec file. */
 159   if (exec_bfd == NULL)
 160     return;
 161
 162   /* If the timestamp of the exec file has changed, reopen it. */
 163   filename = xstrdup (bfd_get_filename (exec_bfd));
 164   cleanups = make_cleanup (xfree, filename);
 165   res = stat (filename, &st);
 166
 167   if (exec_bfd_mtime && exec_bfd_mtime != st.st_mtime)
 168     exec_file_attach (filename, 0);
 169   else
 170     /* If we accessed the file since last opening it, close it now;
 171        this stops GDB from holding the executable open after it
 172        exits.  */
 173     bfd_cache_close_all ();
 174
 175   do_cleanups (cleanups);
 176 #endif
 177 }
 178 \f
 179 /* If we have both a core file and an exec file,
 180    print a warning if they don't go together.  */
 181
 182 void
 183 validate_files (void)
 184 {
 185   if (exec_bfd && core_bfd)
 186     {
 187       if (!core_file_matches_executable_p (core_bfd, exec_bfd))
 188         warning (_("core file may not match specified executable file."));
 189       else if (bfd_get_mtime (exec_bfd) > bfd_get_mtime (core_bfd))
 190         warning (_("exec file is newer than core file."));
 191     }
 192 }
 193
 194 /* Return the name of the executable file as a string.
 195    ERR nonzero means get error if there is none specified;
 196    otherwise return 0 in that case.  */
 197
 198 char *
 199 get_exec_file (int err)
 200 {
 201   if (exec_bfd)
 202     return bfd_get_filename (exec_bfd);
 203   if (!err)
 204     return NULL;
 205
 206   error (_("No executable file specified.\n\
 207 Use the \"file\" or \"exec-file\" command."));
 208   return NULL;
 209 }
 210 \f
 211
 212 /* Report a memory error by throwing a MEMORY_ERROR error.  */
 213
 214 void
 215 memory_error (int status, CORE_ADDR memaddr)
 216 {
 217   if (status == EIO)
 218     /* Actually, address between memaddr and memaddr + len was out of
 219        bounds.  */
 220     throw_error (MEMORY_ERROR,
 221                  _("Cannot access memory at address %s"),
 222                  paddress (target_gdbarch, memaddr));
 223   else
 224     throw_error (MEMORY_ERROR,
 225                  _("Error accessing memory address %s: %s."),
 226                  paddress (target_gdbarch, memaddr),
 227                  safe_strerror (status));
 228 }
 229
 230 /* Same as target_read_memory, but report an error if can't read.  */
 231
 232 void
 233 read_memory (CORE_ADDR memaddr, gdb_byte *myaddr, int len)
 234 {
 235   int status;
 236   status = target_read_memory (memaddr, myaddr, len);
 237   if (status != 0)
 238     memory_error (status, memaddr);
 239 }
 240
 241 /* Same as target_read_stack, but report an error if can't read.  */
 242
 243 void
 244 read_stack (CORE_ADDR memaddr, gdb_byte *myaddr, int len)
 245 {
 246   int status;
 247   status = target_read_stack (memaddr, myaddr, len);
 248   if (status != 0)
 249     memory_error (status, memaddr);
 250 }
 251
 252 /* Argument / return result struct for use with
 253    do_captured_read_memory_integer().  MEMADDR and LEN are filled in
 254    by gdb_read_memory_integer().  RESULT is the contents that were
 255    successfully read from MEMADDR of length LEN.  */
 256
 257 struct captured_read_memory_integer_arguments
 258 {
 259   CORE_ADDR memaddr;
 260   int len;
 261   enum bfd_endian byte_order;
 262   LONGEST result;
 263 };
 264
 265 /* Helper function for gdb_read_memory_integer().  DATA must be a
 266    pointer to a captured_read_memory_integer_arguments struct.
 267    Return 1 if successful.  Note that the catch_errors() interface
 268    will return 0 if an error occurred while reading memory.  This
 269    choice of return code is so that we can distinguish between
 270    success and failure.  */
 271
 272 static int
 273 do_captured_read_memory_integer (void *data)
 274 {
 275   struct captured_read_memory_integer_arguments *args = (struct captured_read_memory_integer_arguments*) data;
 276   CORE_ADDR memaddr = args->memaddr;
 277   int len = args->len;
 278   enum bfd_endian byte_order = args->byte_order;
 279
 280   args->result = read_memory_integer (memaddr, len, byte_order);
 281
 282   return 1;
 283 }
 284
 285 /* Read memory at MEMADDR of length LEN and put the contents in
 286    RETURN_VALUE.  Return 0 if MEMADDR couldn't be read and non-zero
 287    if successful.  */
 288
 289 int
 290 safe_read_memory_integer (CORE_ADDR memaddr, int len, enum bfd_endian byte_order,
 291                           LONGEST *return_value)
 292 {
 293   int status;
 294   struct captured_read_memory_integer_arguments args;
 295   args.memaddr = memaddr;
 296   args.len = len;
 297   args.byte_order = byte_order;
 298
 299   status = catch_errors (do_captured_read_memory_integer, &args,
 300                         "", RETURN_MASK_ALL);
 301   if (status)
 302     *return_value = args.result;
 303
 304   return status;
 305 }
 306
 307 LONGEST
 308 read_memory_integer (CORE_ADDR memaddr, int len, enum bfd_endian byte_order)
 309 {
 310   gdb_byte buf[sizeof (LONGEST)];
 311
 312   read_memory (memaddr, buf, len);
 313   return extract_signed_integer (buf, len, byte_order);
 314 }
 315
 316 ULONGEST
 317 read_memory_unsigned_integer (CORE_ADDR memaddr, int len, enum bfd_endian byte_order)
 318 {
 319   gdb_byte buf[sizeof (ULONGEST)];
 320
 321   read_memory (memaddr, buf, len);
 322   return extract_unsigned_integer (buf, len, byte_order);
 323 }
 324
 325 void
 326 read_memory_string (CORE_ADDR memaddr, char *buffer, int max_len)
 327 {
 328   char *cp;
 329   int i;
 330   int cnt;
 331
 332   cp = buffer;
 333   while (1)
 334     {
 335       if (cp - buffer >= max_len)
 336         {
 337           buffer[max_len - 1] = '\0';
 338           break;
 339         }
 340       cnt = max_len - (cp - buffer);
 341       if (cnt > 8)
 342         cnt = 8;
 343       read_memory (memaddr + (int) (cp - buffer), cp, cnt);
 344       for (i = 0; i < cnt && *cp; i++, cp++)
 345         ;                       /* null body */
 346
 347       if (i < cnt && !*cp)
 348         break;
 349     }
 350 }
 351
 352 CORE_ADDR
 353 read_memory_typed_address (CORE_ADDR addr, struct type *type)
 354 {
 355   gdb_byte *buf = alloca (TYPE_LENGTH (type));
 356   read_memory (addr, buf, TYPE_LENGTH (type));
 357   return extract_typed_address (buf, type);
 358 }
 359
 360 /* Same as target_write_memory, but report an error if can't write.  */
 361 void
 362 write_memory (CORE_ADDR memaddr, const bfd_byte *myaddr, int len)
 363 {
 364   int status;
 365   status = target_write_memory (memaddr, myaddr, len);
 366   if (status != 0)
 367     memory_error (status, memaddr);
 368 }
 369
 370 /* Store VALUE at ADDR in the inferior as a LEN-byte unsigned integer.  */
 371 void
 372 write_memory_unsigned_integer (CORE_ADDR addr, int len, enum bfd_endian byte_order,
 373                                ULONGEST value)
 374 {
 375   gdb_byte *buf = alloca (len);
 376   store_unsigned_integer (buf, len, byte_order, value);
 377   write_memory (addr, buf, len);
 378 }
 379
 380 /* Store VALUE at ADDR in the inferior as a LEN-byte signed integer.  */
 381 void
 382 write_memory_signed_integer (CORE_ADDR addr, int len, enum bfd_endian byte_order,
 383                              LONGEST value)
 384 {
 385   gdb_byte *buf = alloca (len);
 386   store_signed_integer (buf, len, byte_order, value);
 387   write_memory (addr, buf, len);
 388 }
 389 \f
 390 /* The current default bfd target.  Points to storage allocated for
 391    gnutarget_string.  */
 392 char *gnutarget;
 393
 394 /* Same thing, except it is "auto" not NULL for the default case.  */
 395 static char *gnutarget_string;
 396 static void
 397 show_gnutarget_string (struct ui_file *file, int from_tty,
 398                        struct cmd_list_element *c, const char *value)
 399 {
 400   fprintf_filtered (file, _("The current BFD target is \"%s\".\n"), value);
 401 }
 402
 403 static void set_gnutarget_command (char *, int, struct cmd_list_element *);
 404
 405 static void
 406 set_gnutarget_command (char *ignore, int from_tty, struct cmd_list_element *c)
 407 {
 408   if (strcmp (gnutarget_string, "auto") == 0)
 409     gnutarget = NULL;
 410   else
 411     gnutarget = gnutarget_string;
 412 }
 413
 414 /* Set the gnutarget.  */
 415 void
 416 set_gnutarget (char *newtarget)
 417 {
 418   if (gnutarget_string != NULL)
 419     xfree (gnutarget_string);
 420   gnutarget_string = xstrdup (newtarget);
 421   set_gnutarget_command (NULL, 0, NULL);
 422 }
 423
 424 void
 425 _initialize_core (void)
 426 {
 427   struct cmd_list_element *c;
 428   c = add_cmd ("core-file", class_files, core_file_command, _("\
 429 Use FILE as core dump for examining memory and registers.\n\
 430 No arg means have no core file.  This command has been superseded by the\n\
 431 `target core' and `detach' commands."), &cmdlist);
 432   set_cmd_completer (c, filename_completer);
 433
 434
 435   add_setshow_string_noescape_cmd ("gnutarget", class_files,
 436                                    &gnutarget_string, _("\
 437 Set the current BFD target."), _("\
 438 Show the current BFD target."), _("\
 439 Use `set gnutarget auto' to specify automatic detection."),
 440                                    set_gnutarget_command,
 441                                    show_gnutarget_string,
 442                                    &setlist, &showlist);
 443
 444   if (getenv ("GNUTARGET"))
 445     set_gnutarget (getenv ("GNUTARGET"));
 446   else
 447     set_gnutarget ("auto");
 448 }