gdb/corefile.c

   1 /* Core dump and executable file functions above target vector, for GDB.
   2
   3    Copyright (C) 1986-2025 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 <signal.h>
  21 #include <fcntl.h>
  22 #include "event-top.h"
  23 #include "extract-store-integer.h"
  24 #include "inferior.h"
  25 #include "symtab.h"
  26 #include "command.h"
  27 #include "cli/cli-cmds.h"
  28 #include "bfd.h"
  29 #include "target.h"
  30 #include "gdbcore.h"
  31 #include "dis-asm.h"
  32 #include <sys/stat.h>
  33 #include "completer.h"
  34 #include "observable.h"
  35 #include "cli/cli-utils.h"
  36 #include "gdbarch.h"
  37 #include "interps.h"
  38 #include "arch-utils.h"
  39
  40 void
  41 reopen_exec_file (void)
  42 {
  43   bfd *exec_bfd = current_program_space->exec_bfd ();
  44
  45   /* Don't do anything if there isn't an exec file.  */
  46   if (exec_bfd == nullptr)
  47     return;
  48
  49   /* The main executable can't be an in-memory BFD object.  If it was then
  50      the use of bfd_stat below would not work as expected.  */
  51   gdb_assert ((exec_bfd->flags & BFD_IN_MEMORY) == 0);
  52
  53   /* If the timestamp of the exec file has changed, reopen it.  */
  54   struct stat st;
  55   int res = gdb_bfd_stat (exec_bfd, &st);
  56
  57   if (res == 0
  58       && current_program_space->ebfd_mtime != 0
  59       && current_program_space->ebfd_mtime != st.st_mtime)
  60     exec_file_attach (bfd_get_filename (exec_bfd), 0);
  61 }
  62 \f
  63 /* If we have both a core file and an exec file,
  64    print a warning if they don't go together.  */
  65
  66 void
  67 validate_files (void)
  68 {
  69   if (current_program_space->exec_bfd () && current_program_space->core_bfd ())
  70     {
  71       if (!core_file_matches_executable_p (current_program_space->core_bfd (),
  72                                            current_program_space->exec_bfd ()))
  73         warning (_("core file may not match specified executable file."));
  74       else if (gdb_bfd_get_mtime (current_program_space->exec_bfd ())
  75                > gdb_bfd_get_mtime (current_program_space->core_bfd ()))
  76         warning (_("exec file is newer than core file."));
  77     }
  78 }
  79
  80 /* See arch-utils.h.  */
  81
  82 core_file_exec_context
  83 default_core_parse_exec_context (struct gdbarch *gdbarch, bfd *cbfd)
  84 {
  85   return {};
  86 }
  87 \f
  88
  89 std::string
  90 memory_error_message (enum target_xfer_status err,
  91                       struct gdbarch *gdbarch, CORE_ADDR memaddr)
  92 {
  93   switch (err)
  94     {
  95     case TARGET_XFER_E_IO:
  96       /* Actually, address between memaddr and memaddr + len was out of
  97          bounds.  */
  98       return string_printf (_("Cannot access memory at address %s"),
  99                             paddress (gdbarch, memaddr));
 100     case TARGET_XFER_UNAVAILABLE:
 101       return string_printf (_("Memory at address %s unavailable."),
 102                             paddress (gdbarch, memaddr));
 103     default:
 104       internal_error ("unhandled target_xfer_status: %s (%s)",
 105                       target_xfer_status_to_string (err),
 106                       plongest (err));
 107     }
 108 }
 109
 110 /* Report a memory error by throwing a suitable exception.  */
 111
 112 void
 113 memory_error (enum target_xfer_status err, CORE_ADDR memaddr)
 114 {
 115   enum errors exception = GDB_NO_ERROR;
 116
 117   /* Build error string.  */
 118   std::string str
 119     = memory_error_message (err, current_inferior ()->arch (), memaddr);
 120
 121   /* Choose the right error to throw.  */
 122   switch (err)
 123     {
 124     case TARGET_XFER_E_IO:
 125       exception = MEMORY_ERROR;
 126       break;
 127     case TARGET_XFER_UNAVAILABLE:
 128       exception = NOT_AVAILABLE_ERROR;
 129       break;
 130     }
 131
 132   /* Throw it.  */
 133   throw_error (exception, ("%s"), str.c_str ());
 134 }
 135
 136 /* Helper function.  */
 137
 138 static void
 139 read_memory_object (enum target_object object, CORE_ADDR memaddr,
 140                     gdb_byte *myaddr, ssize_t len)
 141 {
 142   ULONGEST xfered = 0;
 143
 144   while (xfered < len)
 145     {
 146       enum target_xfer_status status;
 147       ULONGEST xfered_len;
 148
 149       status = target_xfer_partial (current_inferior ()->top_target (), object,
 150                                     NULL, myaddr + xfered, NULL,
 151                                     memaddr + xfered, len - xfered,
 152                                     &xfered_len);
 153
 154       if (status != TARGET_XFER_OK)
 155         memory_error (status == TARGET_XFER_EOF ? TARGET_XFER_E_IO : status,
 156                       memaddr + xfered);
 157
 158       xfered += xfered_len;
 159       QUIT;
 160     }
 161 }
 162
 163 /* Same as target_read_memory, but report an error if can't read.  */
 164
 165 void
 166 read_memory (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len)
 167 {
 168   read_memory_object (TARGET_OBJECT_MEMORY, memaddr, myaddr, len);
 169 }
 170
 171 /* Same as target_read_stack, but report an error if can't read.  */
 172
 173 void
 174 read_stack (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len)
 175 {
 176   read_memory_object (TARGET_OBJECT_STACK_MEMORY, memaddr, myaddr, len);
 177 }
 178
 179 /* Same as target_read_code, but report an error if can't read.  */
 180
 181 void
 182 read_code (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len)
 183 {
 184   read_memory_object (TARGET_OBJECT_CODE_MEMORY, memaddr, myaddr, len);
 185 }
 186
 187 /* Read memory at MEMADDR of length LEN and put the contents in
 188    RETURN_VALUE.  Return 0 if MEMADDR couldn't be read and non-zero
 189    if successful.  */
 190
 191 int
 192 safe_read_memory_integer (CORE_ADDR memaddr, int len,
 193                           enum bfd_endian byte_order,
 194                           LONGEST *return_value)
 195 {
 196   gdb_byte buf[sizeof (LONGEST)];
 197
 198   if (target_read_memory (memaddr, buf, len))
 199     return 0;
 200
 201   *return_value = extract_signed_integer (buf, len, byte_order);
 202   return 1;
 203 }
 204
 205 /* Read memory at MEMADDR of length LEN and put the contents in
 206    RETURN_VALUE.  Return 0 if MEMADDR couldn't be read and non-zero
 207    if successful.  */
 208
 209 int
 210 safe_read_memory_unsigned_integer (CORE_ADDR memaddr, int len,
 211                                    enum bfd_endian byte_order,
 212                                    ULONGEST *return_value)
 213 {
 214   gdb_byte buf[sizeof (ULONGEST)];
 215
 216   if (target_read_memory (memaddr, buf, len))
 217     return 0;
 218
 219   *return_value = extract_unsigned_integer (buf, len, byte_order);
 220   return 1;
 221 }
 222
 223 LONGEST
 224 read_memory_integer (CORE_ADDR memaddr, int len,
 225                      enum bfd_endian byte_order)
 226 {
 227   gdb_byte buf[sizeof (LONGEST)];
 228
 229   read_memory (memaddr, buf, len);
 230   return extract_signed_integer (buf, len, byte_order);
 231 }
 232
 233 ULONGEST
 234 read_memory_unsigned_integer (CORE_ADDR memaddr, int len,
 235                               enum bfd_endian byte_order)
 236 {
 237   gdb_byte buf[sizeof (ULONGEST)];
 238
 239   read_memory (memaddr, buf, len);
 240   return extract_unsigned_integer (buf, len, byte_order);
 241 }
 242
 243 LONGEST
 244 read_code_integer (CORE_ADDR memaddr, int len,
 245                    enum bfd_endian byte_order)
 246 {
 247   gdb_byte buf[sizeof (LONGEST)];
 248
 249   read_code (memaddr, buf, len);
 250   return extract_signed_integer (buf, len, byte_order);
 251 }
 252
 253 ULONGEST
 254 read_code_unsigned_integer (CORE_ADDR memaddr, int len,
 255                             enum bfd_endian byte_order)
 256 {
 257   gdb_byte buf[sizeof (ULONGEST)];
 258
 259   read_code (memaddr, buf, len);
 260   return extract_unsigned_integer (buf, len, byte_order);
 261 }
 262
 263 CORE_ADDR
 264 read_memory_typed_address (CORE_ADDR addr, struct type *type)
 265 {
 266   gdb_byte *buf = (gdb_byte *) alloca (type->length ());
 267
 268   read_memory (addr, buf, type->length ());
 269   return extract_typed_address (buf, type);
 270 }
 271
 272 /* See gdbcore.h.  */
 273
 274 void
 275 write_memory (CORE_ADDR memaddr,
 276               const bfd_byte *myaddr, ssize_t len)
 277 {
 278   int status;
 279
 280   status = target_write_memory (memaddr, myaddr, len);
 281   if (status != 0)
 282     memory_error (TARGET_XFER_E_IO, memaddr);
 283 }
 284
 285 /* Notify interpreters and observers that INF's memory was changed.  */
 286
 287 static void
 288 notify_memory_changed (inferior *inf, CORE_ADDR addr, ssize_t len,
 289                        const bfd_byte *data)
 290 {
 291   interps_notify_memory_changed (inf, addr, len, data);
 292   gdb::observers::memory_changed.notify (inf, addr, len, data);
 293 }
 294
 295 /* Same as write_memory, but notify 'memory_changed' observers.  */
 296
 297 void
 298 write_memory_with_notification (CORE_ADDR memaddr, const bfd_byte *myaddr,
 299                                 ssize_t len)
 300 {
 301   write_memory (memaddr, myaddr, len);
 302   notify_memory_changed (current_inferior (), memaddr, len, myaddr);
 303 }
 304
 305 /* Store VALUE at ADDR in the inferior as a LEN-byte unsigned
 306    integer.  */
 307 void
 308 write_memory_unsigned_integer (CORE_ADDR addr, int len,
 309                                enum bfd_endian byte_order,
 310                                ULONGEST value)
 311 {
 312   gdb_byte *buf = (gdb_byte *) alloca (len);
 313
 314   store_unsigned_integer (buf, len, byte_order, value);
 315   write_memory (addr, buf, len);
 316 }
 317
 318 /* Store VALUE at ADDR in the inferior as a LEN-byte signed
 319    integer.  */
 320 void
 321 write_memory_signed_integer (CORE_ADDR addr, int len,
 322                              enum bfd_endian byte_order,
 323                              LONGEST value)
 324 {
 325   gdb_byte *buf = (gdb_byte *) alloca (len);
 326
 327   store_signed_integer (buf, len, byte_order, value);
 328   write_memory (addr, buf, len);
 329 }
 330 \f
 331 /* The current default bfd target.  Points to storage allocated for
 332    gnutarget_string.  */
 333 const char *gnutarget;
 334
 335 /* Same thing, except it is "auto" not NULL for the default case.  */
 336 static std::string gnutarget_string;
 337 static void
 338 show_gnutarget_string (struct ui_file *file, int from_tty,
 339                        struct cmd_list_element *c,
 340                        const char *value)
 341 {
 342   gdb_printf (file,
 343               _("The current BFD target is \"%s\".\n"), value);
 344 }
 345
 346 static void
 347 set_gnutarget_command (const char *ignore, int from_tty,
 348                        struct cmd_list_element *c)
 349 {
 350   const char *gend = gnutarget_string.c_str () + gnutarget_string.size ();
 351   gend = remove_trailing_whitespace (gnutarget_string.c_str (), gend);
 352   gnutarget_string
 353     = gnutarget_string.substr (0, gend - gnutarget_string.data ());
 354
 355   if (gnutarget_string == "auto")
 356     gnutarget = NULL;
 357   else
 358     gnutarget = gnutarget_string.c_str ();
 359 }
 360
 361 /* A completion function for "set gnutarget".  */
 362
 363 static void
 364 complete_set_gnutarget (struct cmd_list_element *cmd,
 365                         completion_tracker &tracker,
 366                         const char *text, const char *word)
 367 {
 368   static const char **bfd_targets;
 369
 370   if (bfd_targets == NULL)
 371     {
 372       int last;
 373
 374       bfd_targets = bfd_target_list ();
 375       for (last = 0; bfd_targets[last] != NULL; ++last)
 376         ;
 377
 378       bfd_targets = XRESIZEVEC (const char *, bfd_targets, last + 2);
 379       bfd_targets[last] = "auto";
 380       bfd_targets[last + 1] = NULL;
 381     }
 382
 383   complete_on_enum (tracker, bfd_targets, text, word);
 384 }
 385
 386 /* Set the gnutarget.  */
 387 void
 388 set_gnutarget (const char *newtarget)
 389 {
 390   gnutarget_string = newtarget;
 391   set_gnutarget_command (NULL, 0, NULL);
 392 }
 393
 394 INIT_GDB_FILE (core)
 395 {
 396   cmd_list_element *core_file_cmd
 397     = add_cmd ("core-file", class_files, core_file_command, _("\
 398 Use FILE as core dump for examining memory and registers.\n\
 399 Usage: core-file FILE\n\
 400 No arg means have no core file.  This command has been superseded by the\n\
 401 `target core' and `detach' commands."), &cmdlist);
 402   set_cmd_completer (core_file_cmd, deprecated_filename_completer);
 403
 404   set_show_commands set_show_gnutarget
 405     = add_setshow_string_noescape_cmd ("gnutarget", class_files,
 406                                        &gnutarget_string, _("\
 407 Set the current BFD target."), _("\
 408 Show the current BFD target."), _("\
 409 Use `set gnutarget auto' to specify automatic detection."),
 410                                        set_gnutarget_command,
 411                                        show_gnutarget_string,
 412                                        &setlist, &showlist);
 413   set_cmd_completer (set_show_gnutarget.set, complete_set_gnutarget);
 414
 415   add_alias_cmd ("g", set_show_gnutarget.set, class_files, 1, &setlist);
 416
 417   if (getenv ("GNUTARGET"))
 418     set_gnutarget (getenv ("GNUTARGET"));
 419   else
 420     set_gnutarget ("auto");
 421 }