| 1 | /* Generate a core file for the inferior process. |
| 2 | |
| 3 | Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007 |
| 4 | Free Software Foundation, Inc. |
| 5 | |
| 6 | This file is part of GDB. |
| 7 | |
| 8 | This program is free software; you can redistribute it and/or modify |
| 9 | it under the terms of the GNU General Public License as published by |
| 10 | the Free Software Foundation; either version 3 of the License, or |
| 11 | (at your option) any later version. |
| 12 | |
| 13 | This program is distributed in the hope that it will be useful, |
| 14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | GNU General Public License for more details. |
| 17 | |
| 18 | You should have received a copy of the GNU General Public License |
| 19 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 20 | |
| 21 | #include "defs.h" |
| 22 | #include "elf-bfd.h" |
| 23 | #include "infcall.h" |
| 24 | #include "inferior.h" |
| 25 | #include "gdbcore.h" |
| 26 | #include "objfiles.h" |
| 27 | #include "symfile.h" |
| 28 | |
| 29 | #include "cli/cli-decode.h" |
| 30 | |
| 31 | #include "gdb_assert.h" |
| 32 | |
| 33 | /* The largest amount of memory to read from the target at once. We |
| 34 | must throttle it to limit the amount of memory used by GDB during |
| 35 | generate-core-file for programs with large resident data. */ |
| 36 | #define MAX_COPY_BYTES (1024 * 1024) |
| 37 | |
| 38 | static char *default_gcore_target (void); |
| 39 | static enum bfd_architecture default_gcore_arch (void); |
| 40 | static unsigned long default_gcore_mach (void); |
| 41 | static int gcore_memory_sections (bfd *); |
| 42 | |
| 43 | /* Generate a core file from the inferior process. */ |
| 44 | |
| 45 | static void |
| 46 | gcore_command (char *args, int from_tty) |
| 47 | { |
| 48 | struct cleanup *old_chain; |
| 49 | char *corefilename, corefilename_buffer[40]; |
| 50 | asection *note_sec = NULL; |
| 51 | bfd *obfd; |
| 52 | void *note_data = NULL; |
| 53 | int note_size = 0; |
| 54 | |
| 55 | /* No use generating a corefile without a target process. */ |
| 56 | if (!target_has_execution) |
| 57 | noprocess (); |
| 58 | |
| 59 | if (args && *args) |
| 60 | corefilename = args; |
| 61 | else |
| 62 | { |
| 63 | /* Default corefile name is "core.PID". */ |
| 64 | sprintf (corefilename_buffer, "core.%d", PIDGET (inferior_ptid)); |
| 65 | corefilename = corefilename_buffer; |
| 66 | } |
| 67 | |
| 68 | if (info_verbose) |
| 69 | fprintf_filtered (gdb_stdout, |
| 70 | "Opening corefile '%s' for output.\n", corefilename); |
| 71 | |
| 72 | /* Open the output file. */ |
| 73 | obfd = bfd_openw (corefilename, default_gcore_target ()); |
| 74 | if (!obfd) |
| 75 | error (_("Failed to open '%s' for output."), corefilename); |
| 76 | |
| 77 | /* Need a cleanup that will close the file (FIXME: delete it?). */ |
| 78 | old_chain = make_cleanup_bfd_close (obfd); |
| 79 | |
| 80 | bfd_set_format (obfd, bfd_core); |
| 81 | bfd_set_arch_mach (obfd, default_gcore_arch (), default_gcore_mach ()); |
| 82 | |
| 83 | /* An external target method must build the notes section. */ |
| 84 | note_data = target_make_corefile_notes (obfd, ¬e_size); |
| 85 | |
| 86 | /* Create the note section. */ |
| 87 | if (note_data != NULL && note_size != 0) |
| 88 | { |
| 89 | note_sec = bfd_make_section_anyway_with_flags (obfd, "note0", |
| 90 | SEC_HAS_CONTENTS |
| 91 | | SEC_READONLY |
| 92 | | SEC_ALLOC); |
| 93 | if (note_sec == NULL) |
| 94 | error (_("Failed to create 'note' section for corefile: %s"), |
| 95 | bfd_errmsg (bfd_get_error ())); |
| 96 | |
| 97 | bfd_set_section_vma (obfd, note_sec, 0); |
| 98 | bfd_set_section_alignment (obfd, note_sec, 0); |
| 99 | bfd_set_section_size (obfd, note_sec, note_size); |
| 100 | } |
| 101 | |
| 102 | /* Now create the memory/load sections. */ |
| 103 | if (gcore_memory_sections (obfd) == 0) |
| 104 | error (_("gcore: failed to get corefile memory sections from target.")); |
| 105 | |
| 106 | /* Write out the contents of the note section. */ |
| 107 | if (note_data != NULL && note_size != 0) |
| 108 | { |
| 109 | if (!bfd_set_section_contents (obfd, note_sec, note_data, 0, note_size)) |
| 110 | warning (_("writing note section (%s)"), bfd_errmsg (bfd_get_error ())); |
| 111 | } |
| 112 | |
| 113 | /* Succeeded. */ |
| 114 | fprintf_filtered (gdb_stdout, "Saved corefile %s\n", corefilename); |
| 115 | |
| 116 | /* Clean-ups will close the output file and free malloc memory. */ |
| 117 | do_cleanups (old_chain); |
| 118 | return; |
| 119 | } |
| 120 | |
| 121 | static unsigned long |
| 122 | default_gcore_mach (void) |
| 123 | { |
| 124 | #if 1 /* See if this even matters... */ |
| 125 | return 0; |
| 126 | #else |
| 127 | |
| 128 | const struct bfd_arch_info *bfdarch = gdbarch_bfd_arch_info (current_gdbarch); |
| 129 | |
| 130 | if (bfdarch != NULL) |
| 131 | return bfdarch->mach; |
| 132 | if (exec_bfd == NULL) |
| 133 | error (_("Can't find default bfd machine type (need execfile).")); |
| 134 | |
| 135 | return bfd_get_mach (exec_bfd); |
| 136 | #endif /* 1 */ |
| 137 | } |
| 138 | |
| 139 | static enum bfd_architecture |
| 140 | default_gcore_arch (void) |
| 141 | { |
| 142 | const struct bfd_arch_info * bfdarch = gdbarch_bfd_arch_info |
| 143 | (current_gdbarch); |
| 144 | |
| 145 | if (bfdarch != NULL) |
| 146 | return bfdarch->arch; |
| 147 | if (exec_bfd == NULL) |
| 148 | error (_("Can't find bfd architecture for corefile (need execfile).")); |
| 149 | |
| 150 | return bfd_get_arch (exec_bfd); |
| 151 | } |
| 152 | |
| 153 | static char * |
| 154 | default_gcore_target (void) |
| 155 | { |
| 156 | /* FIXME: This may only work for ELF targets. */ |
| 157 | if (exec_bfd == NULL) |
| 158 | return NULL; |
| 159 | else |
| 160 | return bfd_get_target (exec_bfd); |
| 161 | } |
| 162 | |
| 163 | /* Derive a reasonable stack segment by unwinding the target stack, |
| 164 | and store its limits in *BOTTOM and *TOP. Return non-zero if |
| 165 | successful. */ |
| 166 | |
| 167 | static int |
| 168 | derive_stack_segment (bfd_vma *bottom, bfd_vma *top) |
| 169 | { |
| 170 | struct frame_info *fi, *tmp_fi; |
| 171 | |
| 172 | gdb_assert (bottom); |
| 173 | gdb_assert (top); |
| 174 | |
| 175 | /* Can't succeed without stack and registers. */ |
| 176 | if (!target_has_stack || !target_has_registers) |
| 177 | return 0; |
| 178 | |
| 179 | /* Can't succeed without current frame. */ |
| 180 | fi = get_current_frame (); |
| 181 | if (fi == NULL) |
| 182 | return 0; |
| 183 | |
| 184 | /* Save frame pointer of TOS frame. */ |
| 185 | *top = get_frame_base (fi); |
| 186 | /* If current stack pointer is more "inner", use that instead. */ |
| 187 | if (gdbarch_inner_than (current_gdbarch, get_frame_sp (fi), *top)) |
| 188 | *top = get_frame_sp (fi); |
| 189 | |
| 190 | /* Find prev-most frame. */ |
| 191 | while ((tmp_fi = get_prev_frame (fi)) != NULL) |
| 192 | fi = tmp_fi; |
| 193 | |
| 194 | /* Save frame pointer of prev-most frame. */ |
| 195 | *bottom = get_frame_base (fi); |
| 196 | |
| 197 | /* Now canonicalize their order, so that BOTTOM is a lower address |
| 198 | (as opposed to a lower stack frame). */ |
| 199 | if (*bottom > *top) |
| 200 | { |
| 201 | bfd_vma tmp_vma; |
| 202 | |
| 203 | tmp_vma = *top; |
| 204 | *top = *bottom; |
| 205 | *bottom = tmp_vma; |
| 206 | } |
| 207 | |
| 208 | return 1; |
| 209 | } |
| 210 | |
| 211 | /* Derive a reasonable heap segment for ABFD by looking at sbrk and |
| 212 | the static data sections. Store its limits in *BOTTOM and *TOP. |
| 213 | Return non-zero if successful. */ |
| 214 | |
| 215 | static int |
| 216 | derive_heap_segment (bfd *abfd, bfd_vma *bottom, bfd_vma *top) |
| 217 | { |
| 218 | bfd_vma top_of_data_memory = 0; |
| 219 | bfd_vma top_of_heap = 0; |
| 220 | bfd_size_type sec_size; |
| 221 | struct value *zero, *sbrk; |
| 222 | bfd_vma sec_vaddr; |
| 223 | asection *sec; |
| 224 | |
| 225 | gdb_assert (bottom); |
| 226 | gdb_assert (top); |
| 227 | |
| 228 | /* This function depends on being able to call a function in the |
| 229 | inferior. */ |
| 230 | if (!target_has_execution) |
| 231 | return 0; |
| 232 | |
| 233 | /* The following code assumes that the link map is arranged as |
| 234 | follows (low to high addresses): |
| 235 | |
| 236 | --------------------------------- |
| 237 | | text sections | |
| 238 | --------------------------------- |
| 239 | | data sections (including bss) | |
| 240 | --------------------------------- |
| 241 | | heap | |
| 242 | --------------------------------- */ |
| 243 | |
| 244 | for (sec = abfd->sections; sec; sec = sec->next) |
| 245 | { |
| 246 | if (bfd_get_section_flags (abfd, sec) & SEC_DATA |
| 247 | || strcmp (".bss", bfd_section_name (abfd, sec)) == 0) |
| 248 | { |
| 249 | sec_vaddr = bfd_get_section_vma (abfd, sec); |
| 250 | sec_size = bfd_get_section_size (sec); |
| 251 | if (sec_vaddr + sec_size > top_of_data_memory) |
| 252 | top_of_data_memory = sec_vaddr + sec_size; |
| 253 | } |
| 254 | } |
| 255 | |
| 256 | /* Now get the top-of-heap by calling sbrk in the inferior. */ |
| 257 | if (lookup_minimal_symbol ("sbrk", NULL, NULL) != NULL) |
| 258 | { |
| 259 | sbrk = find_function_in_inferior ("sbrk"); |
| 260 | if (sbrk == NULL) |
| 261 | return 0; |
| 262 | } |
| 263 | else if (lookup_minimal_symbol ("_sbrk", NULL, NULL) != NULL) |
| 264 | { |
| 265 | sbrk = find_function_in_inferior ("_sbrk"); |
| 266 | if (sbrk == NULL) |
| 267 | return 0; |
| 268 | } |
| 269 | else |
| 270 | return 0; |
| 271 | |
| 272 | zero = value_from_longest (builtin_type_int, 0); |
| 273 | gdb_assert (zero); |
| 274 | sbrk = call_function_by_hand (sbrk, 1, &zero); |
| 275 | if (sbrk == NULL) |
| 276 | return 0; |
| 277 | top_of_heap = value_as_long (sbrk); |
| 278 | |
| 279 | /* Return results. */ |
| 280 | if (top_of_heap > top_of_data_memory) |
| 281 | { |
| 282 | *bottom = top_of_data_memory; |
| 283 | *top = top_of_heap; |
| 284 | return 1; |
| 285 | } |
| 286 | |
| 287 | /* No additional heap space needs to be saved. */ |
| 288 | return 0; |
| 289 | } |
| 290 | |
| 291 | static void |
| 292 | make_output_phdrs (bfd *obfd, asection *osec, void *ignored) |
| 293 | { |
| 294 | int p_flags = 0; |
| 295 | int p_type; |
| 296 | |
| 297 | /* FIXME: these constants may only be applicable for ELF. */ |
| 298 | if (strncmp (bfd_section_name (obfd, osec), "load", 4) == 0) |
| 299 | p_type = PT_LOAD; |
| 300 | else |
| 301 | p_type = PT_NOTE; |
| 302 | |
| 303 | p_flags |= PF_R; /* Segment is readable. */ |
| 304 | if (!(bfd_get_section_flags (obfd, osec) & SEC_READONLY)) |
| 305 | p_flags |= PF_W; /* Segment is writable. */ |
| 306 | if (bfd_get_section_flags (obfd, osec) & SEC_CODE) |
| 307 | p_flags |= PF_X; /* Segment is executable. */ |
| 308 | |
| 309 | bfd_record_phdr (obfd, p_type, 1, p_flags, 0, 0, 0, 0, 1, &osec); |
| 310 | } |
| 311 | |
| 312 | static int |
| 313 | gcore_create_callback (CORE_ADDR vaddr, unsigned long size, |
| 314 | int read, int write, int exec, void *data) |
| 315 | { |
| 316 | bfd *obfd = data; |
| 317 | asection *osec; |
| 318 | flagword flags = SEC_ALLOC | SEC_HAS_CONTENTS | SEC_LOAD; |
| 319 | |
| 320 | /* If the memory segment has no permissions set, ignore it, otherwise |
| 321 | when we later try to access it for read/write, we'll get an error |
| 322 | or jam the kernel. */ |
| 323 | if (read == 0 && write == 0 && exec == 0) |
| 324 | { |
| 325 | if (info_verbose) |
| 326 | { |
| 327 | fprintf_filtered (gdb_stdout, "Ignore segment, %s bytes at 0x%s\n", |
| 328 | paddr_d (size), paddr_nz (vaddr)); |
| 329 | } |
| 330 | |
| 331 | return 0; |
| 332 | } |
| 333 | |
| 334 | if (write == 0) |
| 335 | { |
| 336 | /* See if this region of memory lies inside a known file on disk. |
| 337 | If so, we can avoid copying its contents by clearing SEC_LOAD. */ |
| 338 | struct objfile *objfile; |
| 339 | struct obj_section *objsec; |
| 340 | |
| 341 | ALL_OBJSECTIONS (objfile, objsec) |
| 342 | { |
| 343 | bfd *abfd = objfile->obfd; |
| 344 | asection *asec = objsec->the_bfd_section; |
| 345 | bfd_vma align = (bfd_vma) 1 << bfd_get_section_alignment (abfd, |
| 346 | asec); |
| 347 | bfd_vma start = objsec->addr & -align; |
| 348 | bfd_vma end = (objsec->endaddr + align - 1) & -align; |
| 349 | /* Match if either the entire memory region lies inside the |
| 350 | section (i.e. a mapping covering some pages of a large |
| 351 | segment) or the entire section lies inside the memory region |
| 352 | (i.e. a mapping covering multiple small sections). |
| 353 | |
| 354 | This BFD was synthesized from reading target memory, |
| 355 | we don't want to omit that. */ |
| 356 | if (((vaddr >= start && vaddr + size <= end) |
| 357 | || (start >= vaddr && end <= vaddr + size)) |
| 358 | && !(bfd_get_file_flags (abfd) & BFD_IN_MEMORY)) |
| 359 | { |
| 360 | flags &= ~SEC_LOAD; |
| 361 | flags |= SEC_NEVER_LOAD; |
| 362 | goto keep; /* break out of two nested for loops */ |
| 363 | } |
| 364 | } |
| 365 | |
| 366 | keep: |
| 367 | flags |= SEC_READONLY; |
| 368 | } |
| 369 | |
| 370 | if (exec) |
| 371 | flags |= SEC_CODE; |
| 372 | else |
| 373 | flags |= SEC_DATA; |
| 374 | |
| 375 | osec = bfd_make_section_anyway_with_flags (obfd, "load", flags); |
| 376 | if (osec == NULL) |
| 377 | { |
| 378 | warning (_("Couldn't make gcore segment: %s"), |
| 379 | bfd_errmsg (bfd_get_error ())); |
| 380 | return 1; |
| 381 | } |
| 382 | |
| 383 | if (info_verbose) |
| 384 | { |
| 385 | fprintf_filtered (gdb_stdout, "Save segment, %s bytes at 0x%s\n", |
| 386 | paddr_d (size), paddr_nz (vaddr)); |
| 387 | } |
| 388 | |
| 389 | bfd_set_section_size (obfd, osec, size); |
| 390 | bfd_set_section_vma (obfd, osec, vaddr); |
| 391 | bfd_section_lma (obfd, osec) = 0; /* ??? bfd_set_section_lma? */ |
| 392 | return 0; |
| 393 | } |
| 394 | |
| 395 | static int |
| 396 | objfile_find_memory_regions (int (*func) (CORE_ADDR, unsigned long, |
| 397 | int, int, int, void *), |
| 398 | void *obfd) |
| 399 | { |
| 400 | /* Use objfile data to create memory sections. */ |
| 401 | struct objfile *objfile; |
| 402 | struct obj_section *objsec; |
| 403 | bfd_vma temp_bottom, temp_top; |
| 404 | |
| 405 | /* Call callback function for each objfile section. */ |
| 406 | ALL_OBJSECTIONS (objfile, objsec) |
| 407 | { |
| 408 | bfd *ibfd = objfile->obfd; |
| 409 | asection *isec = objsec->the_bfd_section; |
| 410 | flagword flags = bfd_get_section_flags (ibfd, isec); |
| 411 | int ret; |
| 412 | |
| 413 | if ((flags & SEC_ALLOC) || (flags & SEC_LOAD)) |
| 414 | { |
| 415 | int size = bfd_section_size (ibfd, isec); |
| 416 | int ret; |
| 417 | |
| 418 | ret = (*func) (objsec->addr, bfd_section_size (ibfd, isec), |
| 419 | 1, /* All sections will be readable. */ |
| 420 | (flags & SEC_READONLY) == 0, /* Writable. */ |
| 421 | (flags & SEC_CODE) != 0, /* Executable. */ |
| 422 | obfd); |
| 423 | if (ret != 0) |
| 424 | return ret; |
| 425 | } |
| 426 | } |
| 427 | |
| 428 | /* Make a stack segment. */ |
| 429 | if (derive_stack_segment (&temp_bottom, &temp_top)) |
| 430 | (*func) (temp_bottom, temp_top - temp_bottom, |
| 431 | 1, /* Stack section will be readable. */ |
| 432 | 1, /* Stack section will be writable. */ |
| 433 | 0, /* Stack section will not be executable. */ |
| 434 | obfd); |
| 435 | |
| 436 | /* Make a heap segment. */ |
| 437 | if (derive_heap_segment (exec_bfd, &temp_bottom, &temp_top)) |
| 438 | (*func) (temp_bottom, temp_top - temp_bottom, |
| 439 | 1, /* Heap section will be readable. */ |
| 440 | 1, /* Heap section will be writable. */ |
| 441 | 0, /* Heap section will not be executable. */ |
| 442 | obfd); |
| 443 | |
| 444 | return 0; |
| 445 | } |
| 446 | |
| 447 | static void |
| 448 | gcore_copy_callback (bfd *obfd, asection *osec, void *ignored) |
| 449 | { |
| 450 | bfd_size_type size, total_size = bfd_section_size (obfd, osec); |
| 451 | file_ptr offset = 0; |
| 452 | struct cleanup *old_chain = NULL; |
| 453 | void *memhunk; |
| 454 | |
| 455 | /* Read-only sections are marked; we don't have to copy their contents. */ |
| 456 | if ((bfd_get_section_flags (obfd, osec) & SEC_LOAD) == 0) |
| 457 | return; |
| 458 | |
| 459 | /* Only interested in "load" sections. */ |
| 460 | if (strncmp ("load", bfd_section_name (obfd, osec), 4) != 0) |
| 461 | return; |
| 462 | |
| 463 | size = min (total_size, MAX_COPY_BYTES); |
| 464 | memhunk = xmalloc (size); |
| 465 | /* ??? This is crap since xmalloc should never return NULL. */ |
| 466 | if (memhunk == NULL) |
| 467 | error (_("Not enough memory to create corefile.")); |
| 468 | old_chain = make_cleanup (xfree, memhunk); |
| 469 | |
| 470 | while (total_size > 0) |
| 471 | { |
| 472 | if (size > total_size) |
| 473 | size = total_size; |
| 474 | |
| 475 | if (target_read_memory (bfd_section_vma (obfd, osec) + offset, |
| 476 | memhunk, size) != 0) |
| 477 | { |
| 478 | warning (_("Memory read failed for corefile section, %s bytes at 0x%s."), |
| 479 | paddr_d (size), paddr (bfd_section_vma (obfd, osec))); |
| 480 | break; |
| 481 | } |
| 482 | if (!bfd_set_section_contents (obfd, osec, memhunk, offset, size)) |
| 483 | { |
| 484 | warning (_("Failed to write corefile contents (%s)."), |
| 485 | bfd_errmsg (bfd_get_error ())); |
| 486 | break; |
| 487 | } |
| 488 | |
| 489 | total_size -= size; |
| 490 | offset += size; |
| 491 | } |
| 492 | |
| 493 | do_cleanups (old_chain); /* Frees MEMHUNK. */ |
| 494 | } |
| 495 | |
| 496 | static int |
| 497 | gcore_memory_sections (bfd *obfd) |
| 498 | { |
| 499 | if (target_find_memory_regions (gcore_create_callback, obfd) != 0) |
| 500 | return 0; /* FIXME: error return/msg? */ |
| 501 | |
| 502 | /* Record phdrs for section-to-segment mapping. */ |
| 503 | bfd_map_over_sections (obfd, make_output_phdrs, NULL); |
| 504 | |
| 505 | /* Copy memory region contents. */ |
| 506 | bfd_map_over_sections (obfd, gcore_copy_callback, NULL); |
| 507 | |
| 508 | return 1; |
| 509 | } |
| 510 | |
| 511 | void |
| 512 | _initialize_gcore (void) |
| 513 | { |
| 514 | add_com ("generate-core-file", class_files, gcore_command, _("\ |
| 515 | Save a core file with the current state of the debugged process.\n\ |
| 516 | Argument is optional filename. Default filename is 'core.<process_id>'.")); |
| 517 | |
| 518 | add_com_alias ("gcore", "generate-core-file", class_files, 1); |
| 519 | exec_set_find_memory_regions (objfile_find_memory_regions); |
| 520 | } |