1/* OS ABI variant handling for GDB. 2 Copyright 2001, 2002, 2003 Free Software Foundation, Inc. 3 4 This file is part of GDB. 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, 19 Boston, MA 02111-1307, USA. */ 20 21#include "defs.h" 22 23#include "gdb_assert.h" 24#include "gdb_string.h" 25 26#include "osabi.h" 27#include "arch-utils.h" 28#include "gdbcmd.h" 29#include "command.h" 30 31#include "elf-bfd.h" 32 33#ifndef GDB_OSABI_DEFAULT 34#define GDB_OSABI_DEFAULT GDB_OSABI_UNKNOWN 35#endif 36 37/* State for the "set osabi" command. */ 38static enum { osabi_auto, osabi_default, osabi_user } user_osabi_state; 39static enum gdb_osabi user_selected_osabi; 40static const char *gdb_osabi_available_names[GDB_OSABI_INVALID + 3] = { 41 "auto", 42 "default", 43 "none", 44 NULL 45}; 46static const char *set_osabi_string; 47 48/* This table matches the indices assigned to enum gdb_osabi. Keep 49 them in sync. */ 50static const char * const gdb_osabi_names[] = 51{ 52 "none", 53 54 "SVR4", 55 "GNU/Hurd", 56 "Solaris", 57 "OSF/1", 58 "GNU/Linux", 59 "FreeBSD a.out", 60 "FreeBSD ELF", 61 "NetBSD a.out", 62 "NetBSD ELF", 63 "OpenBSD ELF", 64 "Windows CE", 65 "DJGPP", 66 "NetWare", 67 "Irix", 68 "LynxOS", 69 "Interix", 70 "HP/UX ELF", 71 "HP/UX SOM", 72 73 "ARM EABI v1", 74 "ARM EABI v2", 75 "ARM APCS", 76 "QNX Neutrino", 77 78 "Cygwin", 79 80 "<invalid>" 81}; 82 83const char * 84gdbarch_osabi_name (enum gdb_osabi osabi) 85{ 86 if (osabi >= GDB_OSABI_UNKNOWN && osabi < GDB_OSABI_INVALID) 87 return gdb_osabi_names[osabi]; 88 89 return gdb_osabi_names[GDB_OSABI_INVALID]; 90} 91 92/* Handler for a given architecture/OS ABI pair. There should be only 93 one handler for a given OS ABI each architecture family. */ 94struct gdb_osabi_handler 95{ 96 struct gdb_osabi_handler *next; 97 const struct bfd_arch_info *arch_info; 98 enum gdb_osabi osabi; 99 void (*init_osabi)(struct gdbarch_info, struct gdbarch *); 100}; 101 102static struct gdb_osabi_handler *gdb_osabi_handler_list; 103 104void 105gdbarch_register_osabi (enum bfd_architecture arch, unsigned long machine, 106 enum gdb_osabi osabi, 107 void (*init_osabi)(struct gdbarch_info, 108 struct gdbarch *)) 109{ 110 struct gdb_osabi_handler **handler_p; 111 const struct bfd_arch_info *arch_info = bfd_lookup_arch (arch, machine); 112 const char **name_ptr; 113 114 /* Registering an OS ABI handler for "unknown" is not allowed. */ 115 if (osabi == GDB_OSABI_UNKNOWN) 116 { 117 internal_error 118 (__FILE__, __LINE__, 119 "gdbarch_register_osabi: An attempt to register a handler for " 120 "OS ABI \"%s\" for architecture %s was made. The handler will " 121 "not be registered", 122 gdbarch_osabi_name (osabi), 123 bfd_printable_arch_mach (arch, machine)); 124 return; 125 } 126 127 gdb_assert (arch_info); 128 129 for (handler_p = &gdb_osabi_handler_list; *handler_p != NULL; 130 handler_p = &(*handler_p)->next) 131 { 132 if ((*handler_p)->arch_info == arch_info 133 && (*handler_p)->osabi == osabi) 134 { 135 internal_error 136 (__FILE__, __LINE__, 137 "gdbarch_register_osabi: A handler for OS ABI \"%s\" " 138 "has already been registered for architecture %s", 139 gdbarch_osabi_name (osabi), 140 arch_info->printable_name); 141 /* If user wants to continue, override previous definition. */ 142 (*handler_p)->init_osabi = init_osabi; 143 return; 144 } 145 } 146 147 (*handler_p) 148 = (struct gdb_osabi_handler *) xmalloc (sizeof (struct gdb_osabi_handler)); 149 (*handler_p)->next = NULL; 150 (*handler_p)->arch_info = arch_info; 151 (*handler_p)->osabi = osabi; 152 (*handler_p)->init_osabi = init_osabi; 153 154 /* Add this OS ABI to the list of enum values for "set osabi", if it isn't 155 already there. */ 156 for (name_ptr = gdb_osabi_available_names; *name_ptr; name_ptr ++) 157 { 158 if (*name_ptr == gdbarch_osabi_name (osabi)) 159 return; 160 } 161 *name_ptr++ = gdbarch_osabi_name (osabi); 162 *name_ptr = NULL; 163} 164 165 166/* Sniffer to find the OS ABI for a given file's architecture and flavour. 167 It is legal to have multiple sniffers for each arch/flavour pair, to 168 disambiguate one OS's a.out from another, for example. The first sniffer 169 to return something other than GDB_OSABI_UNKNOWN wins, so a sniffer should 170 be careful to claim a file only if it knows for sure what it is. */ 171struct gdb_osabi_sniffer 172{ 173 struct gdb_osabi_sniffer *next; 174 enum bfd_architecture arch; /* bfd_arch_unknown == wildcard */ 175 enum bfd_flavour flavour; 176 enum gdb_osabi (*sniffer)(bfd *); 177}; 178 179static struct gdb_osabi_sniffer *gdb_osabi_sniffer_list; 180 181void 182gdbarch_register_osabi_sniffer (enum bfd_architecture arch, 183 enum bfd_flavour flavour, 184 enum gdb_osabi (*sniffer_fn)(bfd *)) 185{ 186 struct gdb_osabi_sniffer *sniffer; 187 188 sniffer = 189 (struct gdb_osabi_sniffer *) xmalloc (sizeof (struct gdb_osabi_sniffer)); 190 sniffer->arch = arch; 191 sniffer->flavour = flavour; 192 sniffer->sniffer = sniffer_fn; 193 194 sniffer->next = gdb_osabi_sniffer_list; 195 gdb_osabi_sniffer_list = sniffer; 196} 197 198 199enum gdb_osabi 200gdbarch_lookup_osabi (bfd *abfd) 201{ 202 struct gdb_osabi_sniffer *sniffer; 203 enum gdb_osabi osabi, match; 204 int match_specific; 205 206 /* If we aren't in "auto" mode, return the specified OS ABI. */ 207 if (user_osabi_state == osabi_user) 208 return user_selected_osabi; 209 210 /* If we don't have a binary, return the default OS ABI (if set) or 211 an inconclusive result (otherwise). */ 212 if (abfd == NULL) 213 { 214 if (GDB_OSABI_DEFAULT != GDB_OSABI_UNKNOWN) 215 return GDB_OSABI_DEFAULT; 216 else 217 return GDB_OSABI_UNINITIALIZED; 218 } 219 220 match = GDB_OSABI_UNKNOWN; 221 match_specific = 0; 222 223 for (sniffer = gdb_osabi_sniffer_list; sniffer != NULL; 224 sniffer = sniffer->next) 225 { 226 if ((sniffer->arch == bfd_arch_unknown /* wildcard */ 227 || sniffer->arch == bfd_get_arch (abfd)) 228 && sniffer->flavour == bfd_get_flavour (abfd)) 229 { 230 osabi = (*sniffer->sniffer) (abfd); 231 if (osabi < GDB_OSABI_UNKNOWN || osabi >= GDB_OSABI_INVALID) 232 { 233 internal_error 234 (__FILE__, __LINE__, 235 "gdbarch_lookup_osabi: invalid OS ABI (%d) from sniffer " 236 "for architecture %s flavour %d", 237 (int) osabi, 238 bfd_printable_arch_mach (bfd_get_arch (abfd), 0), 239 (int) bfd_get_flavour (abfd)); 240 } 241 else if (osabi != GDB_OSABI_UNKNOWN) 242 { 243 /* A specific sniffer always overrides a generic sniffer. 244 Croak on multiple match if the two matches are of the 245 same class. If the user wishes to continue, we'll use 246 the first match. */ 247 if (match != GDB_OSABI_UNKNOWN) 248 { 249 if ((match_specific && sniffer->arch != bfd_arch_unknown) 250 || (!match_specific && sniffer->arch == bfd_arch_unknown)) 251 { 252 internal_error 253 (__FILE__, __LINE__, 254 "gdbarch_lookup_osabi: multiple %sspecific OS ABI " 255 "match for architecture %s flavour %d: first " 256 "match \"%s\", second match \"%s\"", 257 match_specific ? "" : "non-", 258 bfd_printable_arch_mach (bfd_get_arch (abfd), 0), 259 (int) bfd_get_flavour (abfd), 260 gdbarch_osabi_name (match), 261 gdbarch_osabi_name (osabi)); 262 } 263 else if (sniffer->arch != bfd_arch_unknown) 264 { 265 match = osabi; 266 match_specific = 1; 267 } 268 } 269 else 270 { 271 match = osabi; 272 if (sniffer->arch != bfd_arch_unknown) 273 match_specific = 1; 274 } 275 } 276 } 277 } 278 279 /* If we didn't find a match, but a default was specified at configure 280 time, return the default. */ 281 if (GDB_OSABI_DEFAULT != GDB_OSABI_UNKNOWN && match == GDB_OSABI_UNKNOWN) 282 return GDB_OSABI_DEFAULT; 283 else 284 return match; 285} 286 287 288/* Return non-zero if architecture A can run code written for 289 architecture B. */ 290static int 291can_run_code_for (const struct bfd_arch_info *a, const struct bfd_arch_info *b) 292{ 293 /* BFD's 'A->compatible (A, B)' functions return zero if A and B are 294 incompatible. But if they are compatible, it returns the 'more 295 featureful' of the two arches. That is, if A can run code 296 written for B, but B can't run code written for A, then it'll 297 return A. 298 299 struct bfd_arch_info objects are singletons: that is, there's 300 supposed to be exactly one instance for a given machine. So you 301 can tell whether two are equivalent by comparing pointers. */ 302 return (a == b || a->compatible (a, b) == a); 303} 304 305 306void 307gdbarch_init_osabi (struct gdbarch_info info, struct gdbarch *gdbarch) 308{ 309 struct gdb_osabi_handler *handler; 310 311 if (info.osabi == GDB_OSABI_UNKNOWN) 312 { 313 /* Don't complain about an unknown OSABI. Assume the user knows 314 what they are doing. */ 315 return; 316 } 317 318 for (handler = gdb_osabi_handler_list; handler != NULL; 319 handler = handler->next) 320 { 321 if (handler->osabi != info.osabi) 322 continue; 323 324 /* If the architecture described by ARCH_INFO can run code for 325 the architcture we registered the handler for, then the 326 handler is applicable. Note, though, that if the handler is 327 for an architecture that is a superset of ARCH_INFO, we can't 328 use that --- it would be perfectly correct for it to install 329 gdbarch methods that refer to registers / instructions / 330 other facilities ARCH_INFO doesn't have. 331 332 NOTE: kettenis/20021027: There may be more than one machine 333 type that is compatible with the desired machine type. Right 334 now we simply return the first match, which is fine for now. 335 However, we might want to do something smarter in the future. */ 336 /* NOTE: cagney/2003-10-23: The code for "a can_run_code_for b" 337 is implemented using BFD's compatible method (a->compatible 338 (b) == a -- the lowest common denominator between a and b is 339 a). That method's definition of compatible may not be as you 340 expect. For instance the test "amd64 can run code for i386" 341 (or more generally "64-bit ISA can run code for the 32-bit 342 ISA"). BFD doesn't normally consider 32-bit and 64-bit 343 "compatible" so it doesn't succeed. */ 344 if (can_run_code_for (info.bfd_arch_info, handler->arch_info)) 345 { 346 (*handler->init_osabi) (info, gdbarch); 347 return; 348 } 349 } 350 351 warning 352 ("A handler for the OS ABI \"%s\" is not built into this configuration\n" 353 "of GDB. Attempting to continue with the default %s settings.\n", 354 gdbarch_osabi_name (info.osabi), 355 info.bfd_arch_info->printable_name); 356} 357 358/* Limit on the amount of data to be read. */ 359#define MAX_NOTESZ 128 360 361/* Return non-zero if NOTE matches NAME, DESCSZ and TYPE. */ 362 363static int 364check_note (bfd *abfd, asection *sect, const char *note, 365 const char *name, unsigned long descsz, unsigned long type) 366{ 367 unsigned long notesz; 368 unsigned long rdescsz; 369 370 /* Calculate the size of this note. */ 371 notesz = 4 * 3; /* namelen, optlen, type */ 372 notesz += strlen (name) + 1; 373 notesz = ((notesz + 3) & ~3); 374 375 /* If this assertion triggers, increase MAX_NOTESZ. */ 376 gdb_assert (notesz <= MAX_NOTESZ); 377 378 /* Check whether SECT is big enough to comtain the complete note. */ 379 if (notesz > bfd_section_size (abfd, sect)) 380 return 0; 381 382 /* Check the note name. */ 383 if (bfd_h_get_32 (abfd, note) != (strlen (name) + 1) 384 || strcmp (note + 12, name) != 0) 385 return 0; 386 387 /* Check the descriptor size. */ 388 rdescsz = bfd_h_get_32 (abfd, note + 4); 389 if (descsz != (unsigned long)-1 && rdescsz != descsz) 390 return 0; 391 392 notesz += rdescsz; 393 notesz = ((notesz + 3) & ~3); 394 395 /* Check whether SECT is big enough to comtain the complete note. */ 396 if (notesz > bfd_section_size (abfd, sect)) 397 return 0; 398 399 /* Check the note type. */ 400 if (bfd_h_get_32 (abfd, note + 8) != type) 401 return 0; 402 403 return 1; 404} 405 406/* Generic sniffer for ELF flavoured files. */ 407 408void 409generic_elf_osabi_sniff_abi_tag_sections (bfd *abfd, asection *sect, void *obj) 410{ 411 enum gdb_osabi *osabi = obj; 412 const char *name; 413 unsigned int sectsize; 414 char *note; 415 416 name = bfd_get_section_name (abfd, sect); 417 sectsize = bfd_section_size (abfd, sect); 418 419 /* Limit the amount of data to read. */ 420 if (sectsize > MAX_NOTESZ) 421 sectsize = MAX_NOTESZ; 422 423 note = alloca (sectsize); 424 bfd_get_section_contents (abfd, sect, note, 0, sectsize); 425 426 /* .note.ABI-tag notes, used by GNU/Linux and FreeBSD. */ 427 if (strcmp (name, ".note.ABI-tag") == 0) 428 { 429 /* GNU. */ 430 if (check_note (abfd, sect, note, "GNU", 16, NT_GNU_ABI_TAG)) 431 { 432 unsigned int abi_tag = bfd_h_get_32 (abfd, note + 16); 433 434 switch (abi_tag) 435 { 436 case GNU_ABI_TAG_LINUX: 437 *osabi = GDB_OSABI_LINUX; 438 break; 439 440 case GNU_ABI_TAG_HURD: 441 *osabi = GDB_OSABI_HURD; 442 break; 443 444 case GNU_ABI_TAG_SOLARIS: 445 *osabi = GDB_OSABI_SOLARIS; 446 break; 447 448 case GNU_ABI_TAG_FREEBSD: 449 *osabi = GDB_OSABI_FREEBSD_ELF; 450 break; 451 452 case GNU_ABI_TAG_NETBSD: 453 *osabi = GDB_OSABI_NETBSD_ELF; 454 break; 455 456 default: 457 internal_error (__FILE__, __LINE__, "\ 458generic_elf_osabi_sniff_abi_tag_sections: unknown OS number %d", 459 abi_tag); 460 } 461 return; 462 } 463 464 /* FreeBSD. */ 465 if (check_note (abfd, sect, note, "FreeBSD", 4, NT_FREEBSD_ABI_TAG)) 466 { 467 /* There is no need to check the version yet. */ 468 *osabi = GDB_OSABI_FREEBSD_ELF; 469 return; 470 } 471 472 return; 473 } 474 475 /* .note.tag notes, used by FreeBSD. */ 476 if (strcmp (name, ".note.tag") == 0) 477 { 478 /* FreeBSD. */ 479 if (check_note (abfd, sect, note, "FreeBSD", 4, NT_FREEBSD_TAG)) 480 { 481 /* There is no need to check the version yet. */ 482 *osabi = GDB_OSABI_FREEBSD_ELF; 483 return; 484 } 485 if (check_note (abfd, sect, note, "FreeBSD", 4, NT_FREEBSD_NOINIT_TAG)) 486 { 487 /* There is no need to check the version yet. */ 488 *osabi = GDB_OSABI_FREEBSD_ELF; 489 return; 490 } 491 if (check_note (abfd, sect, note, "FreeBSD", -1, NT_FREEBSD_ARCH_TAG)) 492 { 493 /* There is no need to check the version yet. */ 494 *osabi = GDB_OSABI_FREEBSD_ELF; 495 return; 496 } 497 498 return; 499 } 500 501 /* .note.netbsd.ident notes, used by NetBSD. */ 502 if (strcmp (name, ".note.netbsd.ident") == 0 503 && check_note (abfd, sect, note, "NetBSD", 4, NT_NETBSD_IDENT)) 504 { 505 /* There is no need to check the version yet. */ 506 *osabi = GDB_OSABI_NETBSD_ELF; 507 return; 508 } 509 510 /* .note.openbsd.ident notes, used by OpenBSD. */ 511 if (strcmp (name, ".note.openbsd.ident") == 0 512 && check_note (abfd, sect, note, "OpenBSD", 4, NT_OPENBSD_IDENT)) 513 { 514 /* There is no need to check the version yet. */ 515 *osabi = GDB_OSABI_OPENBSD_ELF; 516 return; 517 } 518 519 /* .note.netbsdcore.procinfo notes, used by NetBSD. */ 520 if (strcmp (name, ".note.netbsdcore.procinfo") == 0) 521 { 522 *osabi = GDB_OSABI_NETBSD_ELF; 523 return; 524 } 525} 526 527static enum gdb_osabi 528generic_elf_osabi_sniffer (bfd *abfd) 529{ 530 unsigned int elfosabi; 531 enum gdb_osabi osabi = GDB_OSABI_UNKNOWN; 532 533 elfosabi = elf_elfheader (abfd)->e_ident[EI_OSABI]; 534 535 switch (elfosabi) 536 { 537 case ELFOSABI_NONE: 538 /* When elfosabi is ELFOSABI_NONE (0), then the ELF structures in the 539 file are conforming to the base specification for that machine 540 (there are no OS-specific extensions). In order to determine the 541 real OS in use we must look for OS notes that have been added. */ 542 bfd_map_over_sections (abfd, 543 generic_elf_osabi_sniff_abi_tag_sections, 544 &osabi); 545 break; 546 547 case ELFOSABI_FREEBSD: 548 osabi = GDB_OSABI_FREEBSD_ELF; 549 break; 550 551 case ELFOSABI_NETBSD: 552 osabi = GDB_OSABI_NETBSD_ELF; 553 break; 554 555 case ELFOSABI_LINUX: 556 osabi = GDB_OSABI_LINUX; 557 break; 558 559 case ELFOSABI_HURD: 560 osabi = GDB_OSABI_HURD; 561 break; 562 563 case ELFOSABI_SOLARIS: 564 osabi = GDB_OSABI_SOLARIS; 565 break; 566 567 case ELFOSABI_HPUX: 568 osabi = GDB_OSABI_HPUX_ELF; 569 break; 570 } 571 572 if (osabi == GDB_OSABI_UNKNOWN) 573 { 574 /* The FreeBSD folks have been naughty; they stored the string 575 "FreeBSD" in the padding of the e_ident field of the ELF 576 header to "brand" their ELF binaries in FreeBSD 3.x. */ 577 if (strcmp (&elf_elfheader (abfd)->e_ident[8], "FreeBSD") == 0) 578 osabi = GDB_OSABI_FREEBSD_ELF; 579 } 580 581 return osabi; 582} 583 584static void 585set_osabi (char *args, int from_tty, struct cmd_list_element *c) 586{ 587 struct gdbarch_info info; 588 589 if (strcmp (set_osabi_string, "auto") == 0) 590 user_osabi_state = osabi_auto; 591 else if (strcmp (set_osabi_string, "default") == 0) 592 { 593 user_selected_osabi = GDB_OSABI_DEFAULT; 594 user_osabi_state = osabi_user; 595 } 596 else if (strcmp (set_osabi_string, "none") == 0) 597 { 598 user_selected_osabi = GDB_OSABI_UNKNOWN; 599 user_osabi_state = osabi_user; 600 } 601 else 602 { 603 int i; 604 for (i = 1; i < GDB_OSABI_INVALID; i++) 605 if (strcmp (set_osabi_string, gdbarch_osabi_name (i)) == 0) 606 { 607 user_selected_osabi = i; 608 user_osabi_state = osabi_user; 609 break; 610 } 611 if (i == GDB_OSABI_INVALID) 612 internal_error (__FILE__, __LINE__, 613 "Invalid OS ABI \"%s\" passed to command handler.", 614 set_osabi_string); 615 } 616 617 /* NOTE: At some point (true multiple architectures) we'll need to be more 618 graceful here. */ 619 gdbarch_info_init (&info); 620 if (! gdbarch_update_p (info)) 621 internal_error (__FILE__, __LINE__, "Updating OS ABI failed."); 622} 623 624static void 625show_osabi (char *args, int from_tty) 626{ 627 if (user_osabi_state == osabi_auto) 628 printf_filtered ("The current OS ABI is \"auto\" (currently \"%s\").\n", 629 gdbarch_osabi_name (gdbarch_osabi (current_gdbarch))); 630 else 631 printf_filtered ("The current OS ABI is \"%s\".\n", 632 gdbarch_osabi_name (user_selected_osabi)); 633 634 if (GDB_OSABI_DEFAULT != GDB_OSABI_UNKNOWN) 635 printf_filtered ("The default OS ABI is \"%s\".\n", 636 gdbarch_osabi_name (GDB_OSABI_DEFAULT)); 637} 638 639extern initialize_file_ftype _initialize_gdb_osabi; /* -Wmissing-prototype */ 640 641void 642_initialize_gdb_osabi (void) 643{ 644 struct cmd_list_element *c; 645 646 if (strcmp (gdb_osabi_names[GDB_OSABI_INVALID], "<invalid>") != 0) 647 internal_error 648 (__FILE__, __LINE__, 649 "_initialize_gdb_osabi: gdb_osabi_names[] is inconsistent"); 650 651 /* Register a generic sniffer for ELF flavoured files. */ 652 gdbarch_register_osabi_sniffer (bfd_arch_unknown, 653 bfd_target_elf_flavour, 654 generic_elf_osabi_sniffer); 655 656 /* Register the "set osabi" command. */ 657 c = add_set_enum_cmd ("osabi", class_support, gdb_osabi_available_names, 658 &set_osabi_string, "Set OS ABI of target.", &setlist); 659 660 set_cmd_sfunc (c, set_osabi); 661 add_cmd ("osabi", class_support, show_osabi, "Show OS/ABI of target.", 662 &showlist); 663 user_osabi_state = osabi_auto; 664} 665