gdb/corefile.c

   1 /* Core dump and executable file functions above target vector, for GDB.
   2
   3    Copyright (C) 1986-2024 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include <signal.h>
  22 #include <fcntl.h>
  23 #include "inferior.h"
  24 #include "symtab.h"
  25 #include "command.h"
  26 #include "gdbcmd.h"
  27 #include "bfd.h"
  28 #include "target.h"
  29 #include "gdbcore.h"
  30 #include "dis-asm.h"
  31 #include <sys/stat.h>
  32 #include "completer.h"
  33 #include "observable.h"
  34 #include "cli/cli-utils.h"
  35 #include "gdbarch.h"
  36 #include "interps.h"
  37
  38 void
  39 reopen_exec_file (void)
  40 {
  41   bfd *exec_bfd = current_program_space->exec_bfd ();
  42
  43   /* Don't do anything if there isn't an exec file.  */
  44   if (exec_bfd == nullptr)
  45     return;
  46
  47   /* The main executable can't be an in-memory BFD object.  If it was then
  48      the use of bfd_stat below would not work as expected.  */
  49   gdb_assert ((exec_bfd->flags & BFD_IN_MEMORY) == 0);
  50
  51   /* If the timestamp of the exec file has changed, reopen it.  */
  52   struct stat st;
  53   int res = bfd_stat (exec_bfd, &st);
  54
  55   if (res == 0
  56       && current_program_space->ebfd_mtime != 0
  57       && current_program_space->ebfd_mtime != st.st_mtime)
  58     exec_file_attach (bfd_get_filename (exec_bfd), 0);
  59 }
  60 \f
  61 /* If we have both a core file and an exec file,
  62    print a warning if they don't go together.  */
  63
  64 void
  65 validate_files (void)
  66 {
  67   if (current_program_space->exec_bfd () && current_program_space->core_bfd ())
  68     {
  69       if (!core_file_matches_executable_p (current_program_space->core_bfd (),
  70                                            current_program_space->exec_bfd ()))
  71         warning (_("core file may not match specified executable file."));
  72       else if (bfd_get_mtime (current_program_space->exec_bfd ())
  73                > bfd_get_mtime (current_program_space->core_bfd ()))
  74         warning (_("exec file is newer than core file."));
  75     }
  76 }
  77
  78 /* See gdbsupport/common-inferior.h.  */
  79
  80 const char *
  81 get_exec_file (int err)
  82 {
  83   if (current_program_space->exec_filename != nullptr)
  84     return current_program_space->exec_filename.get ();
  85   if (!err)
  86     return NULL;
  87
  88   error (_("No executable file specified.\n\
  89 Use the \"file\" or \"exec-file\" command."));
  90 }
  91 \f
  92
  93 std::string
  94 memory_error_message (enum target_xfer_status err,
  95                       struct gdbarch *gdbarch, CORE_ADDR memaddr)
  96 {
  97   switch (err)
  98     {
  99     case TARGET_XFER_E_IO:
 100       /* Actually, address between memaddr and memaddr + len was out of
 101          bounds.  */
 102       return string_printf (_("Cannot access memory at address %s"),
 103                             paddress (gdbarch, memaddr));
 104     case TARGET_XFER_UNAVAILABLE:
 105       return string_printf (_("Memory at address %s unavailable."),
 106                             paddress (gdbarch, memaddr));
 107     default:
 108       internal_error ("unhandled target_xfer_status: %s (%s)",
 109                       target_xfer_status_to_string (err),
 110                       plongest (err));
 111     }
 112 }
 113
 114 /* Report a memory error by throwing a suitable exception.  */
 115
 116 void
 117 memory_error (enum target_xfer_status err, CORE_ADDR memaddr)
 118 {
 119   enum errors exception = GDB_NO_ERROR;
 120
 121   /* Build error string.  */
 122   std::string str
 123     = memory_error_message (err, current_inferior ()->arch (), memaddr);
 124
 125   /* Choose the right error to throw.  */
 126   switch (err)
 127     {
 128     case TARGET_XFER_E_IO:
 129       exception = MEMORY_ERROR;
 130       break;
 131     case TARGET_XFER_UNAVAILABLE:
 132       exception = NOT_AVAILABLE_ERROR;
 133       break;
 134     }
 135
 136   /* Throw it.  */
 137   throw_error (exception, ("%s"), str.c_str ());
 138 }
 139
 140 /* Helper function.  */
 141
 142 static void
 143 read_memory_object (enum target_object object, CORE_ADDR memaddr,
 144                     gdb_byte *myaddr, ssize_t len)
 145 {
 146   ULONGEST xfered = 0;
 147
 148   while (xfered < len)
 149     {
 150       enum target_xfer_status status;
 151       ULONGEST xfered_len;
 152
 153       status = target_xfer_partial (current_inferior ()->top_target (), object,
 154                                     NULL, myaddr + xfered, NULL,
 155                                     memaddr + xfered, len - xfered,
 156                                     &xfered_len);
 157
 158       if (status != TARGET_XFER_OK)
 159         memory_error (status == TARGET_XFER_EOF ? TARGET_XFER_E_IO : status,
 160                       memaddr + xfered);
 161
 162       xfered += xfered_len;
 163       QUIT;
 164     }
 165 }
 166
 167 /* Same as target_read_memory, but report an error if can't read.  */
 168
 169 void
 170 read_memory (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len)
 171 {
 172   read_memory_object (TARGET_OBJECT_MEMORY, memaddr, myaddr, len);
 173 }
 174
 175 /* Same as target_read_stack, but report an error if can't read.  */
 176
 177 void
 178 read_stack (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len)
 179 {
 180   read_memory_object (TARGET_OBJECT_STACK_MEMORY, memaddr, myaddr, len);
 181 }
 182
 183 /* Same as target_read_code, but report an error if can't read.  */
 184
 185 void
 186 read_code (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len)
 187 {
 188   read_memory_object (TARGET_OBJECT_CODE_MEMORY, memaddr, myaddr, len);
 189 }
 190
 191 /* Read memory at MEMADDR of length LEN and put the contents in
 192    RETURN_VALUE.  Return 0 if MEMADDR couldn't be read and non-zero
 193    if successful.  */
 194
 195 int
 196 safe_read_memory_integer (CORE_ADDR memaddr, int len,
 197                           enum bfd_endian byte_order,
 198                           LONGEST *return_value)
 199 {
 200   gdb_byte buf[sizeof (LONGEST)];
 201
 202   if (target_read_memory (memaddr, buf, len))
 203     return 0;
 204
 205   *return_value = extract_signed_integer (buf, len, byte_order);
 206   return 1;
 207 }
 208
 209 /* Read memory at MEMADDR of length LEN and put the contents in
 210    RETURN_VALUE.  Return 0 if MEMADDR couldn't be read and non-zero
 211    if successful.  */
 212
 213 int
 214 safe_read_memory_unsigned_integer (CORE_ADDR memaddr, int len,
 215                                    enum bfd_endian byte_order,
 216                                    ULONGEST *return_value)
 217 {
 218   gdb_byte buf[sizeof (ULONGEST)];
 219
 220   if (target_read_memory (memaddr, buf, len))
 221     return 0;
 222
 223   *return_value = extract_unsigned_integer (buf, len, byte_order);
 224   return 1;
 225 }
 226
 227 LONGEST
 228 read_memory_integer (CORE_ADDR memaddr, int len,
 229                      enum bfd_endian byte_order)
 230 {
 231   gdb_byte buf[sizeof (LONGEST)];
 232
 233   read_memory (memaddr, buf, len);
 234   return extract_signed_integer (buf, len, byte_order);
 235 }
 236
 237 ULONGEST
 238 read_memory_unsigned_integer (CORE_ADDR memaddr, int len,
 239                               enum bfd_endian byte_order)
 240 {
 241   gdb_byte buf[sizeof (ULONGEST)];
 242
 243   read_memory (memaddr, buf, len);
 244   return extract_unsigned_integer (buf, len, byte_order);
 245 }
 246
 247 LONGEST
 248 read_code_integer (CORE_ADDR memaddr, int len,
 249                    enum bfd_endian byte_order)
 250 {
 251   gdb_byte buf[sizeof (LONGEST)];
 252
 253   read_code (memaddr, buf, len);
 254   return extract_signed_integer (buf, len, byte_order);
 255 }
 256
 257 ULONGEST
 258 read_code_unsigned_integer (CORE_ADDR memaddr, int len,
 259                             enum bfd_endian byte_order)
 260 {
 261   gdb_byte buf[sizeof (ULONGEST)];
 262
 263   read_code (memaddr, buf, len);
 264   return extract_unsigned_integer (buf, len, byte_order);
 265 }
 266
 267 CORE_ADDR
 268 read_memory_typed_address (CORE_ADDR addr, struct type *type)
 269 {
 270   gdb_byte *buf = (gdb_byte *) alloca (type->length ());
 271
 272   read_memory (addr, buf, type->length ());
 273   return extract_typed_address (buf, type);
 274 }
 275
 276 /* See gdbcore.h.  */
 277
 278 void
 279 write_memory (CORE_ADDR memaddr,
 280               const bfd_byte *myaddr, ssize_t len)
 281 {
 282   int status;
 283
 284   status = target_write_memory (memaddr, myaddr, len);
 285   if (status != 0)
 286     memory_error (TARGET_XFER_E_IO, memaddr);
 287 }
 288
 289 /* Notify interpreters and observers that INF's memory was changed.  */
 290
 291 static void
 292 notify_memory_changed (inferior *inf, CORE_ADDR addr, ssize_t len,
 293                        const bfd_byte *data)
 294 {
 295   interps_notify_memory_changed (inf, addr, len, data);
 296   gdb::observers::memory_changed.notify (inf, addr, len, data);
 297 }
 298
 299 /* Same as write_memory, but notify 'memory_changed' observers.  */
 300
 301 void
 302 write_memory_with_notification (CORE_ADDR memaddr, const bfd_byte *myaddr,
 303                                 ssize_t len)
 304 {
 305   write_memory (memaddr, myaddr, len);
 306   notify_memory_changed (current_inferior (), memaddr, len, myaddr);
 307 }
 308
 309 /* Store VALUE at ADDR in the inferior as a LEN-byte unsigned
 310    integer.  */
 311 void
 312 write_memory_unsigned_integer (CORE_ADDR addr, int len,
 313                                enum bfd_endian byte_order,
 314                                ULONGEST value)
 315 {
 316   gdb_byte *buf = (gdb_byte *) alloca (len);
 317
 318   store_unsigned_integer (buf, len, byte_order, value);
 319   write_memory (addr, buf, len);
 320 }
 321
 322 /* Store VALUE at ADDR in the inferior as a LEN-byte signed
 323    integer.  */
 324 void
 325 write_memory_signed_integer (CORE_ADDR addr, int len,
 326                              enum bfd_endian byte_order,
 327                              LONGEST value)
 328 {
 329   gdb_byte *buf = (gdb_byte *) alloca (len);
 330
 331   store_signed_integer (buf, len, byte_order, value);
 332   write_memory (addr, buf, len);
 333 }
 334 \f
 335 /* The current default bfd target.  Points to storage allocated for
 336    gnutarget_string.  */
 337 const char *gnutarget;
 338
 339 /* Same thing, except it is "auto" not NULL for the default case.  */
 340 static std::string gnutarget_string;
 341 static void
 342 show_gnutarget_string (struct ui_file *file, int from_tty,
 343                        struct cmd_list_element *c,
 344                        const char *value)
 345 {
 346   gdb_printf (file,
 347               _("The current BFD target is \"%s\".\n"), value);
 348 }
 349
 350 static void
 351 set_gnutarget_command (const char *ignore, int from_tty,
 352                        struct cmd_list_element *c)
 353 {
 354   const char *gend = gnutarget_string.c_str () + gnutarget_string.size ();
 355   gend = remove_trailing_whitespace (gnutarget_string.c_str (), gend);
 356   gnutarget_string
 357     = gnutarget_string.substr (0, gend - gnutarget_string.data ());
 358
 359   if (gnutarget_string == "auto")
 360     gnutarget = NULL;
 361   else
 362     gnutarget = gnutarget_string.c_str ();
 363 }
 364
 365 /* A completion function for "set gnutarget".  */
 366
 367 static void
 368 complete_set_gnutarget (struct cmd_list_element *cmd,
 369                         completion_tracker &tracker,
 370                         const char *text, const char *word)
 371 {
 372   static const char **bfd_targets;
 373
 374   if (bfd_targets == NULL)
 375     {
 376       int last;
 377
 378       bfd_targets = bfd_target_list ();
 379       for (last = 0; bfd_targets[last] != NULL; ++last)
 380         ;
 381
 382       bfd_targets = XRESIZEVEC (const char *, bfd_targets, last + 2);
 383       bfd_targets[last] = "auto";
 384       bfd_targets[last + 1] = NULL;
 385     }
 386
 387   complete_on_enum (tracker, bfd_targets, text, word);
 388 }
 389
 390 /* Set the gnutarget.  */
 391 void
 392 set_gnutarget (const char *newtarget)
 393 {
 394   gnutarget_string = newtarget;
 395   set_gnutarget_command (NULL, 0, NULL);
 396 }
 397
 398 void _initialize_core ();
 399 void
 400 _initialize_core ()
 401 {
 402   cmd_list_element *core_file_cmd
 403     = add_cmd ("core-file", class_files, core_file_command, _("\
 404 Use FILE as core dump for examining memory and registers.\n\
 405 Usage: core-file FILE\n\
 406 No arg means have no core file.  This command has been superseded by the\n\
 407 `target core' and `detach' commands."), &cmdlist);
 408   set_cmd_completer (core_file_cmd, filename_completer);
 409
 410
 411   set_show_commands set_show_gnutarget
 412     = add_setshow_string_noescape_cmd ("gnutarget", class_files,
 413                                        &gnutarget_string, _("\
 414 Set the current BFD target."), _("\
 415 Show the current BFD target."), _("\
 416 Use `set gnutarget auto' to specify automatic detection."),
 417                                        set_gnutarget_command,
 418                                        show_gnutarget_string,
 419                                        &setlist, &showlist);
 420   set_cmd_completer (set_show_gnutarget.set, complete_set_gnutarget);
 421
 422   add_alias_cmd ("g", set_show_gnutarget.set, class_files, 1, &setlist);
 423
 424   if (getenv ("GNUTARGET"))
 425     set_gnutarget (getenv ("GNUTARGET"));
 426   else
 427     set_gnutarget ("auto");
 428 }