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