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 Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "defs.h"
  22 #include "gdb_string.h"
  23 #include <errno.h>
  24 #include <signal.h>
  25 #include <fcntl.h>
  26 #include "inferior.h"
  27 #include "symtab.h"
  28 #include "command.h"
  29 #include "gdbcmd.h"
  30 #include "bfd.h"
  31 #include "target.h"
  32 #include "gdbcore.h"
  33 #include "dis-asm.h"
  34 #include "gdb_stat.h"
  35 #include "completer.h"
  36 #include "exceptions.h"
  37
  38 /* Local function declarations.  */
  39
  40 extern void _initialize_core (void);
  41 static void call_extra_exec_file_hooks (char *filename);
  42
  43 /* You can have any number of hooks for `exec_file_command' command to
  44    call.  If there's only one hook, it is set in exec_file_display
  45    hook.  If there are two or more hooks, they are set in
  46    exec_file_extra_hooks[], and deprecated_exec_file_display_hook is
  47    set to a function that calls all of them.  This extra complexity is
  48    needed to preserve compatibility with old code that assumed that
  49    only one hook could be set, and which called
  50    deprecated_exec_file_display_hook directly.  */
  51
  52 typedef void (*hook_type) (char *);
  53
  54 hook_type deprecated_exec_file_display_hook;    /* the original hook */
  55 static hook_type *exec_file_extra_hooks;        /* array of additional hooks */
  56 static int exec_file_hook_count = 0;    /* size of array */
  57
  58 /* Binary file diddling handle for the core file.  */
  59
  60 bfd *core_bfd = NULL;
  61 \f
  62
  63 /* Backward compatability with old way of specifying core files.  */
  64
  65 void
  66 core_file_command (char *filename, int from_tty)
  67 {
  68   struct target_ops *t;
  69
  70   dont_repeat ();               /* Either way, seems bogus. */
  71
  72   t = find_core_target ();
  73   if (t == NULL)
  74     error (_("GDB can't read core files on this machine."));
  75
  76   if (!filename)
  77     (t->to_detach) (filename, from_tty);
  78   else
  79     (t->to_open) (filename, from_tty);
  80 }
  81 \f
  82
  83 /* If there are two or more functions that wish to hook into
  84    exec_file_command, this function will call all of the hook
  85    functions.  */
  86
  87 static void
  88 call_extra_exec_file_hooks (char *filename)
  89 {
  90   int i;
  91
  92   for (i = 0; i < exec_file_hook_count; i++)
  93     (*exec_file_extra_hooks[i]) (filename);
  94 }
  95
  96 /* Call this to specify the hook for exec_file_command to call back.
  97    This is called from the x-window display code.  */
  98
  99 void
 100 specify_exec_file_hook (void (*hook) (char *))
 101 {
 102   hook_type *new_array;
 103
 104   if (deprecated_exec_file_display_hook != NULL)
 105     {
 106       /* There's already a hook installed.  Arrange to have both it
 107        * and the subsequent hooks called. */
 108       if (exec_file_hook_count == 0)
 109         {
 110           /* If this is the first extra hook, initialize the hook array.  */
 111           exec_file_extra_hooks = (hook_type *) xmalloc (sizeof (hook_type));
 112           exec_file_extra_hooks[0] = deprecated_exec_file_display_hook;
 113           deprecated_exec_file_display_hook = call_extra_exec_file_hooks;
 114           exec_file_hook_count = 1;
 115         }
 116
 117       /* Grow the hook array by one and add the new hook to the end.
 118          Yes, it's inefficient to grow it by one each time but since
 119          this is hardly ever called it's not a big deal.  */
 120       exec_file_hook_count++;
 121       new_array =
 122         (hook_type *) xrealloc (exec_file_extra_hooks,
 123                                 exec_file_hook_count * sizeof (hook_type));
 124       exec_file_extra_hooks = new_array;
 125       exec_file_extra_hooks[exec_file_hook_count - 1] = hook;
 126     }
 127   else
 128     deprecated_exec_file_display_hook = hook;
 129 }
 130
 131 /* The exec file must be closed before running an inferior.
 132    If it is needed again after the inferior dies, it must
 133    be reopened.  */
 134
 135 void
 136 close_exec_file (void)
 137 {
 138 #if 0                           /* FIXME */
 139   if (exec_bfd)
 140     bfd_tempclose (exec_bfd);
 141 #endif
 142 }
 143
 144 void
 145 reopen_exec_file (void)
 146 {
 147 #if 0                           /* FIXME */
 148   if (exec_bfd)
 149     bfd_reopen (exec_bfd);
 150 #else
 151   char *filename;
 152   int res;
 153   struct stat st;
 154   long mtime;
 155
 156   /* Don't do anything if there isn't an exec file. */
 157   if (exec_bfd == NULL)
 158     return;
 159
 160   /* If the timestamp of the exec file has changed, reopen it. */
 161   filename = xstrdup (bfd_get_filename (exec_bfd));
 162   make_cleanup (xfree, filename);
 163   res = stat (filename, &st);
 164
 165   if (exec_bfd_mtime && exec_bfd_mtime != st.st_mtime)
 166     exec_file_attach (filename, 0);
 167   else
 168     /* If we accessed the file since last opening it, close it now;
 169        this stops GDB from holding the executable open after it
 170        exits.  */
 171     bfd_cache_close_all ();
 172 #endif
 173 }
 174 \f
 175 /* If we have both a core file and an exec file,
 176    print a warning if they don't go together.  */
 177
 178 void
 179 validate_files (void)
 180 {
 181   if (exec_bfd && core_bfd)
 182     {
 183       if (!core_file_matches_executable_p (core_bfd, exec_bfd))
 184         warning (_("core file may not match specified executable file."));
 185       else if (bfd_get_mtime (exec_bfd) > bfd_get_mtime (core_bfd))
 186         warning (_("exec file is newer than core file."));
 187     }
 188 }
 189
 190 /* Return the name of the executable file as a string.
 191    ERR nonzero means get error if there is none specified;
 192    otherwise return 0 in that case.  */
 193
 194 char *
 195 get_exec_file (int err)
 196 {
 197   if (exec_bfd)
 198     return bfd_get_filename (exec_bfd);
 199   if (!err)
 200     return NULL;
 201
 202   error (_("No executable file specified.\n\
 203 Use the \"file\" or \"exec-file\" command."));
 204   return NULL;
 205 }
 206 \f
 207
 208 /* Report a memory error with error().  */
 209
 210 void
 211 memory_error (int status, CORE_ADDR memaddr)
 212 {
 213   struct ui_file *tmp_stream = mem_fileopen ();
 214   make_cleanup_ui_file_delete (tmp_stream);
 215
 216   if (status == EIO)
 217     {
 218       /* Actually, address between memaddr and memaddr + len
 219          was out of bounds. */
 220       fprintf_unfiltered (tmp_stream, "Cannot access memory at address ");
 221       fputs_filtered (paddress (memaddr), tmp_stream);
 222     }
 223   else
 224     {
 225       fprintf_filtered (tmp_stream, "Error accessing memory address ");
 226       fputs_filtered (paddress (memaddr), tmp_stream);
 227       fprintf_filtered (tmp_stream, ": %s.",
 228                        safe_strerror (status));
 229     }
 230
 231   error_stream (tmp_stream);
 232 }
 233
 234 /* Same as target_read_memory, but report an error if can't read.  */
 235 void
 236 read_memory (CORE_ADDR memaddr, gdb_byte *myaddr, int len)
 237 {
 238   int status;
 239   status = target_read_memory (memaddr, myaddr, len);
 240   if (status != 0)
 241     memory_error (status, memaddr);
 242 }
 243
 244 /* Argument / return result struct for use with
 245    do_captured_read_memory_integer().  MEMADDR and LEN are filled in
 246    by gdb_read_memory_integer().  RESULT is the contents that were
 247    successfully read from MEMADDR of length LEN.  */
 248
 249 struct captured_read_memory_integer_arguments
 250 {
 251   CORE_ADDR memaddr;
 252   int len;
 253   LONGEST result;
 254 };
 255
 256 /* Helper function for gdb_read_memory_integer().  DATA must be a
 257    pointer to a captured_read_memory_integer_arguments struct.
 258    Return 1 if successful.  Note that the catch_errors() interface
 259    will return 0 if an error occurred while reading memory.  This
 260    choice of return code is so that we can distinguish between
 261    success and failure.  */
 262
 263 static int
 264 do_captured_read_memory_integer (void *data)
 265 {
 266   struct captured_read_memory_integer_arguments *args = (struct captured_read_memory_integer_arguments*) data;
 267   CORE_ADDR memaddr = args->memaddr;
 268   int len = args->len;
 269
 270   args->result = read_memory_integer (memaddr, len);
 271
 272   return 1;
 273 }
 274
 275 /* Read memory at MEMADDR of length LEN and put the contents in
 276    RETURN_VALUE.  Return 0 if MEMADDR couldn't be read and non-zero
 277    if successful.  */
 278
 279 int
 280 safe_read_memory_integer (CORE_ADDR memaddr, int len, LONGEST *return_value)
 281 {
 282   int status;
 283   struct captured_read_memory_integer_arguments args;
 284   args.memaddr = memaddr;
 285   args.len = len;
 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)
 297 {
 298   gdb_byte buf[sizeof (LONGEST)];
 299
 300   read_memory (memaddr, buf, len);
 301   return extract_signed_integer (buf, len);
 302 }
 303
 304 ULONGEST
 305 read_memory_unsigned_integer (CORE_ADDR memaddr, int len)
 306 {
 307   gdb_byte buf[sizeof (ULONGEST)];
 308
 309   read_memory (memaddr, buf, len);
 310   return extract_unsigned_integer (buf, len);
 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, ULONGEST value)
 361 {
 362   gdb_byte *buf = alloca (len);
 363   store_unsigned_integer (buf, len, value);
 364   write_memory (addr, buf, len);
 365 }
 366
 367 /* Store VALUE at ADDR in the inferior as a LEN-byte signed integer.  */
 368 void
 369 write_memory_signed_integer (CORE_ADDR addr, int len, LONGEST value)
 370 {
 371   gdb_byte *buf = alloca (len);
 372   store_signed_integer (buf, len, value);
 373   write_memory (addr, buf, len);
 374 }
 375
 376 \f
 377
 378 #if 0
 379 /* Enable after 4.12.  It is not tested.  */
 380
 381 /* Search code.  Targets can just make this their search function, or
 382    if the protocol has a less general search function, they can call this
 383    in the cases it can't handle.  */
 384 void
 385 generic_search (int len, char *data, char *mask, CORE_ADDR startaddr,
 386                 int increment, CORE_ADDR lorange, CORE_ADDR hirange,
 387                 CORE_ADDR *addr_found, char *data_found)
 388 {
 389   int i;
 390   CORE_ADDR curaddr = startaddr;
 391
 392   while (curaddr >= lorange && curaddr < hirange)
 393     {
 394       read_memory (curaddr, data_found, len);
 395       for (i = 0; i < len; ++i)
 396         if ((data_found[i] & mask[i]) != data[i])
 397           goto try_again;
 398       /* It matches.  */
 399       *addr_found = curaddr;
 400       return;
 401
 402     try_again:
 403       curaddr += increment;
 404     }
 405   *addr_found = (CORE_ADDR) 0;
 406   return;
 407 }
 408 #endif /* 0 */
 409 \f
 410 /* The current default bfd target.  Points to storage allocated for
 411    gnutarget_string.  */
 412 char *gnutarget;
 413
 414 /* Same thing, except it is "auto" not NULL for the default case.  */
 415 static char *gnutarget_string;
 416 static void
 417 show_gnutarget_string (struct ui_file *file, int from_tty,
 418                        struct cmd_list_element *c, const char *value)
 419 {
 420   fprintf_filtered (file, _("The current BFD target is \"%s\".\n"), value);
 421 }
 422
 423 static void set_gnutarget_command (char *, int, struct cmd_list_element *);
 424
 425 static void
 426 set_gnutarget_command (char *ignore, int from_tty, struct cmd_list_element *c)
 427 {
 428   if (strcmp (gnutarget_string, "auto") == 0)
 429     gnutarget = NULL;
 430   else
 431     gnutarget = gnutarget_string;
 432 }
 433
 434 /* Set the gnutarget.  */
 435 void
 436 set_gnutarget (char *newtarget)
 437 {
 438   if (gnutarget_string != NULL)
 439     xfree (gnutarget_string);
 440   gnutarget_string = savestring (newtarget, strlen (newtarget));
 441   set_gnutarget_command (NULL, 0, NULL);
 442 }
 443
 444 void
 445 _initialize_core (void)
 446 {
 447   struct cmd_list_element *c;
 448   c = add_cmd ("core-file", class_files, core_file_command, _("\
 449 Use FILE as core dump for examining memory and registers.\n\
 450 No arg means have no core file.  This command has been superseded by the\n\
 451 `target core' and `detach' commands."), &cmdlist);
 452   set_cmd_completer (c, filename_completer);
 453
 454
 455   add_setshow_string_noescape_cmd ("gnutarget", class_files,
 456                                    &gnutarget_string, _("\
 457 Set the current BFD target."), _("\
 458 Show the current BFD target."), _("\
 459 Use `set gnutarget auto' to specify automatic detection."),
 460                                    set_gnutarget_command,
 461                                    show_gnutarget_string,
 462                                    &setlist, &showlist);
 463
 464   if (getenv ("GNUTARGET"))
 465     set_gnutarget (getenv ("GNUTARGET"));
 466   else
 467     set_gnutarget ("auto");
 468 }