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