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   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 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 /* Argument / return result struct for use with
 241    do_captured_read_memory_integer().  MEMADDR and LEN are filled in
 242    by gdb_read_memory_integer().  RESULT is the contents that were
 243    successfully read from MEMADDR of length LEN.  */
 244
 245 struct captured_read_memory_integer_arguments
 246 {
 247   CORE_ADDR memaddr;
 248   int len;
 249   enum bfd_endian byte_order;
 250   LONGEST result;
 251 };
 252
 253 /* Helper function for gdb_read_memory_integer().  DATA must be a
 254    pointer to a captured_read_memory_integer_arguments struct.
 255    Return 1 if successful.  Note that the catch_errors() interface
 256    will return 0 if an error occurred while reading memory.  This
 257    choice of return code is so that we can distinguish between
 258    success and failure.  */
 259
 260 static int
 261 do_captured_read_memory_integer (void *data)
 262 {
 263   struct captured_read_memory_integer_arguments *args = (struct captured_read_memory_integer_arguments*) data;
 264   CORE_ADDR memaddr = args->memaddr;
 265   int len = args->len;
 266   enum bfd_endian byte_order = args->byte_order;
 267
 268   args->result = read_memory_integer (memaddr, len, byte_order);
 269
 270   return 1;
 271 }
 272
 273 /* Read memory at MEMADDR of length LEN and put the contents in
 274    RETURN_VALUE.  Return 0 if MEMADDR couldn't be read and non-zero
 275    if successful.  */
 276
 277 int
 278 safe_read_memory_integer (CORE_ADDR memaddr, int len, enum bfd_endian byte_order,
 279                           LONGEST *return_value)
 280 {
 281   int status;
 282   struct captured_read_memory_integer_arguments args;
 283   args.memaddr = memaddr;
 284   args.len = len;
 285   args.byte_order = byte_order;
 286
 287   status = catch_errors (do_captured_read_memory_integer, &args,
 288                         "", RETURN_MASK_ALL);
 289   if (status)
 290     *return_value = args.result;
 291
 292   return status;
 293 }
 294
 295 LONGEST
 296 read_memory_integer (CORE_ADDR memaddr, int len, enum bfd_endian byte_order)
 297 {
 298   gdb_byte buf[sizeof (LONGEST)];
 299
 300   read_memory (memaddr, buf, len);
 301   return extract_signed_integer (buf, len, byte_order);
 302 }
 303
 304 ULONGEST
 305 read_memory_unsigned_integer (CORE_ADDR memaddr, int len, enum bfd_endian byte_order)
 306 {
 307   gdb_byte buf[sizeof (ULONGEST)];
 308
 309   read_memory (memaddr, buf, len);
 310   return extract_unsigned_integer (buf, len, byte_order);
 311 }
 312
 313 void
 314 read_memory_string (CORE_ADDR memaddr, char *buffer, int max_len)
 315 {
 316   char *cp;
 317   int i;
 318   int cnt;
 319
 320   cp = buffer;
 321   while (1)
 322     {
 323       if (cp - buffer >= max_len)
 324         {
 325           buffer[max_len - 1] = '\0';
 326           break;
 327         }
 328       cnt = max_len - (cp - buffer);
 329       if (cnt > 8)
 330         cnt = 8;
 331       read_memory (memaddr + (int) (cp - buffer), cp, cnt);
 332       for (i = 0; i < cnt && *cp; i++, cp++)
 333         ;                       /* null body */
 334
 335       if (i < cnt && !*cp)
 336         break;
 337     }
 338 }
 339
 340 CORE_ADDR
 341 read_memory_typed_address (CORE_ADDR addr, struct type *type)
 342 {
 343   gdb_byte *buf = alloca (TYPE_LENGTH (type));
 344   read_memory (addr, buf, TYPE_LENGTH (type));
 345   return extract_typed_address (buf, type);
 346 }
 347
 348 /* Same as target_write_memory, but report an error if can't write.  */
 349 void
 350 write_memory (CORE_ADDR memaddr, const bfd_byte *myaddr, int len)
 351 {
 352   int status;
 353   status = target_write_memory (memaddr, myaddr, len);
 354   if (status != 0)
 355     memory_error (status, memaddr);
 356 }
 357
 358 /* Store VALUE at ADDR in the inferior as a LEN-byte unsigned integer.  */
 359 void
 360 write_memory_unsigned_integer (CORE_ADDR addr, int len, enum bfd_endian byte_order,
 361                                ULONGEST value)
 362 {
 363   gdb_byte *buf = alloca (len);
 364   store_unsigned_integer (buf, len, byte_order, value);
 365   write_memory (addr, buf, len);
 366 }
 367
 368 /* Store VALUE at ADDR in the inferior as a LEN-byte signed integer.  */
 369 void
 370 write_memory_signed_integer (CORE_ADDR addr, int len, enum bfd_endian byte_order,
 371                              LONGEST value)
 372 {
 373   gdb_byte *buf = alloca (len);
 374   store_signed_integer (buf, len, byte_order, value);
 375   write_memory (addr, buf, len);
 376 }
 377 \f
 378 /* The current default bfd target.  Points to storage allocated for
 379    gnutarget_string.  */
 380 char *gnutarget;
 381
 382 /* Same thing, except it is "auto" not NULL for the default case.  */
 383 static char *gnutarget_string;
 384 static void
 385 show_gnutarget_string (struct ui_file *file, int from_tty,
 386                        struct cmd_list_element *c, const char *value)
 387 {
 388   fprintf_filtered (file, _("The current BFD target is \"%s\".\n"), value);
 389 }
 390
 391 static void set_gnutarget_command (char *, int, struct cmd_list_element *);
 392
 393 static void
 394 set_gnutarget_command (char *ignore, int from_tty, struct cmd_list_element *c)
 395 {
 396   if (strcmp (gnutarget_string, "auto") == 0)
 397     gnutarget = NULL;
 398   else
 399     gnutarget = gnutarget_string;
 400 }
 401
 402 /* Set the gnutarget.  */
 403 void
 404 set_gnutarget (char *newtarget)
 405 {
 406   if (gnutarget_string != NULL)
 407     xfree (gnutarget_string);
 408   gnutarget_string = xstrdup (newtarget);
 409   set_gnutarget_command (NULL, 0, NULL);
 410 }
 411
 412 void
 413 _initialize_core (void)
 414 {
 415   struct cmd_list_element *c;
 416   c = add_cmd ("core-file", class_files, core_file_command, _("\
 417 Use FILE as core dump for examining memory and registers.\n\
 418 No arg means have no core file.  This command has been superseded by the\n\
 419 `target core' and `detach' commands."), &cmdlist);
 420   set_cmd_completer (c, filename_completer);
 421
 422
 423   add_setshow_string_noescape_cmd ("gnutarget", class_files,
 424                                    &gnutarget_string, _("\
 425 Set the current BFD target."), _("\
 426 Show the current BFD target."), _("\
 427 Use `set gnutarget auto' to specify automatic detection."),
 428                                    set_gnutarget_command,
 429                                    show_gnutarget_string,
 430                                    &setlist, &showlist);
 431
 432   if (getenv ("GNUTARGET"))
 433     set_gnutarget (getenv ("GNUTARGET"));
 434   else
 435     set_gnutarget ("auto");
 436 }