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