| 1 | /* ELF core file support for BFD. |
| 2 | Copyright (C) 1995, 1996 Free Software Foundation, Inc. |
| 3 | |
| 4 | This file is part of BFD, the Binary File Descriptor library. |
| 5 | |
| 6 | This program is free software; you can redistribute it and/or modify |
| 7 | it under the terms of the GNU General Public License as published by |
| 8 | the Free Software Foundation; either version 2 of the License, or |
| 9 | (at your option) any later version. |
| 10 | |
| 11 | This program is distributed in the hope that it will be useful, |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | GNU General Public License for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU General Public License |
| 17 | along with this program; if not, write to the Free Software |
| 18 | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ |
| 19 | /* Core file support */ |
| 20 | |
| 21 | #ifdef HAVE_SYS_PROCFS_H /* Some core file support requires host /proc files */ |
| 22 | #include <signal.h> |
| 23 | #include <sys/procfs.h> |
| 24 | |
| 25 | /* Solaris includes the field pr_who that indicates the thread number within |
| 26 | the process. */ |
| 27 | |
| 28 | #ifdef PIOCOPENLWP |
| 29 | #define get_thread(STATUS) ((((prstatus_t *)(STATUS))->pr_who << 16) \ |
| 30 | | ((prstatus_t *)(STATUS))->pr_pid) |
| 31 | #else |
| 32 | #define get_thread(STATUS) (((prstatus_t *)(STATUS))->pr_pid) |
| 33 | #endif |
| 34 | #else |
| 35 | #define bfd_prstatus(abfd, descdata, descsz, filepos) true |
| 36 | #define bfd_fpregset(abfd, descdata, descsz, filepos) true |
| 37 | #define bfd_prpsinfo(abfd, descdata, descsz, filepos) true |
| 38 | #define get_thread(STATUS) (1) |
| 39 | #endif |
| 40 | |
| 41 | #ifdef HAVE_SYS_PROCFS_H |
| 42 | |
| 43 | static int did_reg; |
| 44 | static int did_reg2; |
| 45 | |
| 46 | static boolean |
| 47 | bfd_prstatus (abfd, descdata, descsz, filepos, thread) |
| 48 | bfd *abfd; |
| 49 | char *descdata; |
| 50 | int descsz; |
| 51 | long filepos; |
| 52 | int thread; |
| 53 | { |
| 54 | asection *newsect; |
| 55 | prstatus_t *status = (prstatus_t *) 0; |
| 56 | |
| 57 | if (descsz == sizeof (prstatus_t)) |
| 58 | { |
| 59 | char secname[100]; |
| 60 | char *p; |
| 61 | |
| 62 | sprintf (secname, ".reg/%d", thread); |
| 63 | p = bfd_alloc (abfd, strlen (secname) + 1); |
| 64 | if (!p) |
| 65 | return false; |
| 66 | strcpy (p, secname); |
| 67 | |
| 68 | newsect = bfd_make_section (abfd, p); |
| 69 | if (newsect == NULL) |
| 70 | return false; |
| 71 | newsect->_raw_size = sizeof (status->pr_reg); |
| 72 | newsect->filepos = filepos + (long) &status->pr_reg; |
| 73 | newsect->flags = SEC_HAS_CONTENTS; |
| 74 | newsect->alignment_power = 2; |
| 75 | if ((core_prstatus (abfd) = bfd_alloc (abfd, descsz)) != NULL) |
| 76 | { |
| 77 | memcpy (core_prstatus (abfd), descdata, descsz); |
| 78 | } |
| 79 | |
| 80 | if (!did_reg++) |
| 81 | { |
| 82 | asection *regsect; |
| 83 | |
| 84 | regsect = bfd_make_section (abfd, ".reg"); |
| 85 | if (regsect == NULL) |
| 86 | return false; |
| 87 | regsect->_raw_size = newsect->_raw_size; |
| 88 | regsect->filepos = newsect->filepos; |
| 89 | regsect->flags = newsect->flags; |
| 90 | regsect->alignment_power = newsect->alignment_power; |
| 91 | } |
| 92 | } |
| 93 | return true; |
| 94 | } |
| 95 | |
| 96 | /* Stash a copy of the prpsinfo structure away for future use. */ |
| 97 | |
| 98 | static boolean |
| 99 | bfd_prpsinfo (abfd, descdata, descsz, filepos) |
| 100 | bfd *abfd; |
| 101 | char *descdata; |
| 102 | int descsz; |
| 103 | long filepos; |
| 104 | { |
| 105 | if (descsz == sizeof (prpsinfo_t)) |
| 106 | { |
| 107 | if ((core_prpsinfo (abfd) = bfd_alloc (abfd, descsz)) == NULL) |
| 108 | return false; |
| 109 | memcpy (core_prpsinfo (abfd), descdata, descsz); |
| 110 | } |
| 111 | return true; |
| 112 | } |
| 113 | |
| 114 | static boolean |
| 115 | bfd_fpregset (abfd, descdata, descsz, filepos, thread) |
| 116 | bfd *abfd; |
| 117 | char *descdata; |
| 118 | int descsz; |
| 119 | long filepos; |
| 120 | int thread; |
| 121 | { |
| 122 | asection *newsect; |
| 123 | char secname[100]; |
| 124 | char *p; |
| 125 | |
| 126 | sprintf (secname, ".reg2/%d", thread); |
| 127 | p = bfd_alloc (abfd, strlen (secname) + 1); |
| 128 | if (!p) |
| 129 | return false; |
| 130 | strcpy (p, secname); |
| 131 | |
| 132 | newsect = bfd_make_section (abfd, p); |
| 133 | if (newsect == NULL) |
| 134 | return false; |
| 135 | newsect->_raw_size = descsz; |
| 136 | newsect->filepos = filepos; |
| 137 | newsect->flags = SEC_HAS_CONTENTS; |
| 138 | newsect->alignment_power = 2; |
| 139 | |
| 140 | if (!did_reg2++) |
| 141 | { |
| 142 | asection *regsect; |
| 143 | |
| 144 | regsect = bfd_make_section (abfd, ".reg2"); |
| 145 | if (regsect == NULL) |
| 146 | return false; |
| 147 | regsect->_raw_size = newsect->_raw_size; |
| 148 | regsect->filepos = newsect->filepos; |
| 149 | regsect->flags = newsect->flags; |
| 150 | regsect->alignment_power = newsect->alignment_power; |
| 151 | } |
| 152 | |
| 153 | return true; |
| 154 | } |
| 155 | |
| 156 | #endif /* HAVE_SYS_PROCFS_H */ |
| 157 | |
| 158 | /* Return a pointer to the args (including the command name) that were |
| 159 | seen by the program that generated the core dump. Note that for |
| 160 | some reason, a spurious space is tacked onto the end of the args |
| 161 | in some (at least one anyway) implementations, so strip it off if |
| 162 | it exists. */ |
| 163 | |
| 164 | char * |
| 165 | elf_core_file_failing_command (abfd) |
| 166 | bfd *abfd; |
| 167 | { |
| 168 | #ifdef HAVE_SYS_PROCFS_H |
| 169 | if (core_prpsinfo (abfd)) |
| 170 | { |
| 171 | prpsinfo_t *p = core_prpsinfo (abfd); |
| 172 | char *scan = p->pr_psargs; |
| 173 | while (*scan++) |
| 174 | {; |
| 175 | } |
| 176 | scan -= 2; |
| 177 | if ((scan > p->pr_psargs) && (*scan == ' ')) |
| 178 | { |
| 179 | *scan = '\000'; |
| 180 | } |
| 181 | return p->pr_psargs; |
| 182 | } |
| 183 | #endif |
| 184 | return NULL; |
| 185 | } |
| 186 | |
| 187 | /* Return the number of the signal that caused the core dump. Presumably, |
| 188 | since we have a core file, we got a signal of some kind, so don't bother |
| 189 | checking the other process status fields, just return the signal number. |
| 190 | */ |
| 191 | |
| 192 | int |
| 193 | elf_core_file_failing_signal (abfd) |
| 194 | bfd *abfd; |
| 195 | { |
| 196 | #ifdef HAVE_SYS_PROCFS_H |
| 197 | if (core_prstatus (abfd)) |
| 198 | { |
| 199 | return ((prstatus_t *) (core_prstatus (abfd)))->pr_cursig; |
| 200 | } |
| 201 | #endif |
| 202 | return -1; |
| 203 | } |
| 204 | |
| 205 | /* Check to see if the core file could reasonably be expected to have |
| 206 | come for the current executable file. Note that by default we return |
| 207 | true unless we find something that indicates that there might be a |
| 208 | problem. |
| 209 | */ |
| 210 | |
| 211 | boolean |
| 212 | elf_core_file_matches_executable_p (core_bfd, exec_bfd) |
| 213 | bfd *core_bfd; |
| 214 | bfd *exec_bfd; |
| 215 | { |
| 216 | #ifdef HAVE_SYS_PROCFS_H |
| 217 | char *corename; |
| 218 | char *execname; |
| 219 | #endif |
| 220 | |
| 221 | /* First, xvecs must match since both are ELF files for the same target. */ |
| 222 | |
| 223 | if (core_bfd->xvec != exec_bfd->xvec) |
| 224 | { |
| 225 | bfd_set_error (bfd_error_system_call); |
| 226 | return false; |
| 227 | } |
| 228 | |
| 229 | #ifdef HAVE_SYS_PROCFS_H |
| 230 | |
| 231 | /* If no prpsinfo, just return true. Otherwise, grab the last component |
| 232 | of the exec'd pathname from the prpsinfo. */ |
| 233 | |
| 234 | if (core_prpsinfo (core_bfd)) |
| 235 | { |
| 236 | corename = (((prpsinfo_t *) core_prpsinfo (core_bfd))->pr_fname); |
| 237 | } |
| 238 | else |
| 239 | { |
| 240 | return true; |
| 241 | } |
| 242 | |
| 243 | /* Find the last component of the executable pathname. */ |
| 244 | |
| 245 | if ((execname = strrchr (exec_bfd->filename, '/')) != NULL) |
| 246 | { |
| 247 | execname++; |
| 248 | } |
| 249 | else |
| 250 | { |
| 251 | execname = (char *) exec_bfd->filename; |
| 252 | } |
| 253 | |
| 254 | /* See if they match */ |
| 255 | |
| 256 | return strcmp (execname, corename) ? false : true; |
| 257 | |
| 258 | #else |
| 259 | |
| 260 | return true; |
| 261 | |
| 262 | #endif /* HAVE_SYS_PROCFS_H */ |
| 263 | } |
| 264 | |
| 265 | /* ELF core files contain a segment of type PT_NOTE, that holds much of |
| 266 | the information that would normally be available from the /proc interface |
| 267 | for the process, at the time the process dumped core. Currently this |
| 268 | includes copies of the prstatus, prpsinfo, and fpregset structures. |
| 269 | |
| 270 | Since these structures are potentially machine dependent in size and |
| 271 | ordering, bfd provides two levels of support for them. The first level, |
| 272 | available on all machines since it does not require that the host |
| 273 | have /proc support or the relevant include files, is to create a bfd |
| 274 | section for each of the prstatus, prpsinfo, and fpregset structures, |
| 275 | without any interpretation of their contents. With just this support, |
| 276 | the bfd client will have to interpret the structures itself. Even with |
| 277 | /proc support, it might want these full structures for it's own reasons. |
| 278 | |
| 279 | In the second level of support, where HAVE_SYS_PROCFS_H is defined, |
| 280 | bfd will pick apart the structures to gather some additional |
| 281 | information that clients may want, such as the general register |
| 282 | set, the name of the exec'ed file and its arguments, the signal (if |
| 283 | any) that caused the core dump, etc. |
| 284 | |
| 285 | */ |
| 286 | |
| 287 | static boolean |
| 288 | elf_corefile_note (abfd, hdr) |
| 289 | bfd *abfd; |
| 290 | Elf_Internal_Phdr *hdr; |
| 291 | { |
| 292 | Elf_External_Note *x_note_p; /* Elf note, external form */ |
| 293 | Elf_Internal_Note i_note; /* Elf note, internal form */ |
| 294 | char *buf = NULL; /* Entire note segment contents */ |
| 295 | char *namedata; /* Name portion of the note */ |
| 296 | char *descdata; /* Descriptor portion of the note */ |
| 297 | char *sectname; /* Name to use for new section */ |
| 298 | long filepos; /* File offset to descriptor data */ |
| 299 | asection *newsect; |
| 300 | int thread = 1; /* Current thread number */ |
| 301 | |
| 302 | did_reg = 0; /* Non-zero if we made .reg section */ |
| 303 | did_reg2 = 0; /* Ditto for .reg2 */ |
| 304 | |
| 305 | if (hdr->p_filesz > 0 |
| 306 | && (buf = (char *) bfd_malloc ((size_t) hdr->p_filesz)) != NULL |
| 307 | && bfd_seek (abfd, hdr->p_offset, SEEK_SET) != -1 |
| 308 | && bfd_read ((PTR) buf, hdr->p_filesz, 1, abfd) == hdr->p_filesz) |
| 309 | { |
| 310 | x_note_p = (Elf_External_Note *) buf; |
| 311 | while ((char *) x_note_p < (buf + hdr->p_filesz)) |
| 312 | { |
| 313 | i_note.namesz = bfd_h_get_32 (abfd, (bfd_byte *) x_note_p->namesz); |
| 314 | i_note.descsz = bfd_h_get_32 (abfd, (bfd_byte *) x_note_p->descsz); |
| 315 | i_note.type = bfd_h_get_32 (abfd, (bfd_byte *) x_note_p->type); |
| 316 | namedata = x_note_p->name; |
| 317 | descdata = namedata + BFD_ALIGN (i_note.namesz, 4); |
| 318 | filepos = hdr->p_offset + (descdata - buf); |
| 319 | switch (i_note.type) |
| 320 | { |
| 321 | case NT_PRSTATUS: |
| 322 | /* process descdata as prstatus info */ |
| 323 | thread = get_thread (descdata); |
| 324 | if (! bfd_prstatus (abfd, descdata, i_note.descsz, filepos, |
| 325 | thread)) |
| 326 | return false; |
| 327 | sectname = NULL; |
| 328 | break; |
| 329 | case NT_FPREGSET: |
| 330 | /* process descdata as fpregset info */ |
| 331 | if (! bfd_fpregset (abfd, descdata, i_note.descsz, filepos, |
| 332 | thread)) |
| 333 | return false; |
| 334 | sectname = NULL; |
| 335 | break; |
| 336 | case NT_PRPSINFO: |
| 337 | /* process descdata as prpsinfo */ |
| 338 | if (! bfd_prpsinfo (abfd, descdata, i_note.descsz, filepos)) |
| 339 | return false; |
| 340 | sectname = ".prpsinfo"; |
| 341 | break; |
| 342 | default: |
| 343 | /* Unknown descriptor, just ignore it. */ |
| 344 | sectname = NULL; |
| 345 | break; |
| 346 | } |
| 347 | if (sectname != NULL) |
| 348 | { |
| 349 | newsect = bfd_make_section (abfd, sectname); |
| 350 | if (newsect == NULL) |
| 351 | return false; |
| 352 | newsect->_raw_size = i_note.descsz; |
| 353 | newsect->filepos = filepos; |
| 354 | newsect->flags = SEC_ALLOC | SEC_HAS_CONTENTS; |
| 355 | newsect->alignment_power = 2; |
| 356 | } |
| 357 | x_note_p = (Elf_External_Note *) |
| 358 | (descdata + BFD_ALIGN (i_note.descsz, 4)); |
| 359 | } |
| 360 | } |
| 361 | if (buf != NULL) |
| 362 | { |
| 363 | free (buf); |
| 364 | } |
| 365 | else if (hdr->p_filesz > 0) |
| 366 | { |
| 367 | return false; |
| 368 | } |
| 369 | return true; |
| 370 | |
| 371 | } |
| 372 | |
| 373 | /* Core files are simply standard ELF formatted files that partition |
| 374 | the file using the execution view of the file (program header table) |
| 375 | rather than the linking view. In fact, there is no section header |
| 376 | table in a core file. |
| 377 | |
| 378 | The process status information (including the contents of the general |
| 379 | register set) and the floating point register set are stored in a |
| 380 | segment of type PT_NOTE. We handcraft a couple of extra bfd sections |
| 381 | that allow standard bfd access to the general registers (.reg) and the |
| 382 | floating point registers (.reg2). |
| 383 | |
| 384 | */ |
| 385 | |
| 386 | const bfd_target * |
| 387 | elf_core_file_p (abfd) |
| 388 | bfd *abfd; |
| 389 | { |
| 390 | Elf_External_Ehdr x_ehdr; /* Elf file header, external form */ |
| 391 | Elf_Internal_Ehdr *i_ehdrp; /* Elf file header, internal form */ |
| 392 | Elf_External_Phdr x_phdr; /* Program header table entry, external form */ |
| 393 | Elf_Internal_Phdr *i_phdrp; /* Program header table, internal form */ |
| 394 | unsigned int phindex; |
| 395 | struct elf_backend_data *ebd; |
| 396 | |
| 397 | /* Read in the ELF header in external format. */ |
| 398 | |
| 399 | if (bfd_read ((PTR) & x_ehdr, sizeof (x_ehdr), 1, abfd) != sizeof (x_ehdr)) |
| 400 | { |
| 401 | if (bfd_get_error () != bfd_error_system_call) |
| 402 | bfd_set_error (bfd_error_wrong_format); |
| 403 | return NULL; |
| 404 | } |
| 405 | |
| 406 | /* Now check to see if we have a valid ELF file, and one that BFD can |
| 407 | make use of. The magic number must match, the address size ('class') |
| 408 | and byte-swapping must match our XVEC entry, and it must have a |
| 409 | program header table (FIXME: See comments re segments at top of this |
| 410 | file). */ |
| 411 | |
| 412 | if (elf_file_p (&x_ehdr) == false) |
| 413 | { |
| 414 | wrong: |
| 415 | bfd_set_error (bfd_error_wrong_format); |
| 416 | return NULL; |
| 417 | } |
| 418 | |
| 419 | /* FIXME, Check EI_VERSION here ! */ |
| 420 | |
| 421 | { |
| 422 | #if ARCH_SIZE == 32 |
| 423 | int desired_address_size = ELFCLASS32; |
| 424 | #endif |
| 425 | #if ARCH_SIZE == 64 |
| 426 | int desired_address_size = ELFCLASS64; |
| 427 | #endif |
| 428 | |
| 429 | if (x_ehdr.e_ident[EI_CLASS] != desired_address_size) |
| 430 | goto wrong; |
| 431 | } |
| 432 | |
| 433 | /* Switch xvec to match the specified byte order. */ |
| 434 | switch (x_ehdr.e_ident[EI_DATA]) |
| 435 | { |
| 436 | case ELFDATA2MSB: /* Big-endian */ |
| 437 | if (! bfd_big_endian (abfd)) |
| 438 | goto wrong; |
| 439 | break; |
| 440 | case ELFDATA2LSB: /* Little-endian */ |
| 441 | if (! bfd_little_endian (abfd)) |
| 442 | goto wrong; |
| 443 | break; |
| 444 | case ELFDATANONE: /* No data encoding specified */ |
| 445 | default: /* Unknown data encoding specified */ |
| 446 | goto wrong; |
| 447 | } |
| 448 | |
| 449 | /* Allocate an instance of the elf_obj_tdata structure and hook it up to |
| 450 | the tdata pointer in the bfd. */ |
| 451 | |
| 452 | elf_tdata (abfd) = |
| 453 | (struct elf_obj_tdata *) bfd_zalloc (abfd, sizeof (struct elf_obj_tdata)); |
| 454 | if (elf_tdata (abfd) == NULL) |
| 455 | return NULL; |
| 456 | |
| 457 | /* FIXME, `wrong' returns from this point onward, leak memory. */ |
| 458 | |
| 459 | /* Now that we know the byte order, swap in the rest of the header */ |
| 460 | i_ehdrp = elf_elfheader (abfd); |
| 461 | elf_swap_ehdr_in (abfd, &x_ehdr, i_ehdrp); |
| 462 | #if DEBUG & 1 |
| 463 | elf_debug_file (i_ehdrp); |
| 464 | #endif |
| 465 | |
| 466 | ebd = get_elf_backend_data (abfd); |
| 467 | |
| 468 | /* Check that the ELF e_machine field matches what this particular |
| 469 | BFD format expects. */ |
| 470 | if (ebd->elf_machine_code != i_ehdrp->e_machine |
| 471 | && (ebd->elf_machine_alt1 == 0 || i_ehdrp->e_machine != ebd->elf_machine_alt1) |
| 472 | && (ebd->elf_machine_alt2 == 0 || i_ehdrp->e_machine != ebd->elf_machine_alt2)) |
| 473 | { |
| 474 | const bfd_target * const *target_ptr; |
| 475 | |
| 476 | if (ebd->elf_machine_code != EM_NONE) |
| 477 | goto wrong; |
| 478 | |
| 479 | /* This is the generic ELF target. Let it match any ELF target |
| 480 | for which we do not have a specific backend. */ |
| 481 | for (target_ptr = bfd_target_vector; *target_ptr != NULL; target_ptr++) |
| 482 | { |
| 483 | struct elf_backend_data *back; |
| 484 | |
| 485 | if ((*target_ptr)->flavour != bfd_target_elf_flavour) |
| 486 | continue; |
| 487 | back = (struct elf_backend_data *) (*target_ptr)->backend_data; |
| 488 | if (back->elf_machine_code == i_ehdrp->e_machine) |
| 489 | { |
| 490 | /* target_ptr is an ELF backend which matches this |
| 491 | object file, so reject the generic ELF target. */ |
| 492 | goto wrong; |
| 493 | } |
| 494 | } |
| 495 | } |
| 496 | |
| 497 | /* If there is no program header, or the type is not a core file, then |
| 498 | we are hosed. */ |
| 499 | if (i_ehdrp->e_phoff == 0 || i_ehdrp->e_type != ET_CORE) |
| 500 | goto wrong; |
| 501 | |
| 502 | /* Allocate space for a copy of the program header table in |
| 503 | internal form, seek to the program header table in the file, |
| 504 | read it in, and convert it to internal form. As a simple sanity |
| 505 | check, verify that the what BFD thinks is the size of each program |
| 506 | header table entry actually matches the size recorded in the file. */ |
| 507 | |
| 508 | if (i_ehdrp->e_phentsize != sizeof (x_phdr)) |
| 509 | goto wrong; |
| 510 | i_phdrp = (Elf_Internal_Phdr *) |
| 511 | bfd_alloc (abfd, sizeof (*i_phdrp) * i_ehdrp->e_phnum); |
| 512 | if (!i_phdrp) |
| 513 | return NULL; |
| 514 | if (bfd_seek (abfd, i_ehdrp->e_phoff, SEEK_SET) == -1) |
| 515 | return NULL; |
| 516 | for (phindex = 0; phindex < i_ehdrp->e_phnum; phindex++) |
| 517 | { |
| 518 | if (bfd_read ((PTR) & x_phdr, sizeof (x_phdr), 1, abfd) |
| 519 | != sizeof (x_phdr)) |
| 520 | return NULL; |
| 521 | elf_swap_phdr_in (abfd, &x_phdr, i_phdrp + phindex); |
| 522 | } |
| 523 | |
| 524 | /* Once all of the program headers have been read and converted, we |
| 525 | can start processing them. */ |
| 526 | |
| 527 | for (phindex = 0; phindex < i_ehdrp->e_phnum; phindex++) |
| 528 | { |
| 529 | bfd_section_from_phdr (abfd, i_phdrp + phindex, phindex); |
| 530 | if ((i_phdrp + phindex)->p_type == PT_NOTE) |
| 531 | { |
| 532 | if (! elf_corefile_note (abfd, i_phdrp + phindex)) |
| 533 | return NULL; |
| 534 | } |
| 535 | } |
| 536 | |
| 537 | /* Remember the entry point specified in the ELF file header. */ |
| 538 | |
| 539 | bfd_get_start_address (abfd) = i_ehdrp->e_entry; |
| 540 | |
| 541 | return abfd->xvec; |
| 542 | } |