gdb/osabi.c

   1 /* OS ABI variant handling for GDB.
   2
   3    Copyright (C) 2001-2023 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 "defs.h"
  21
  22 #include "osabi.h"
  23 #include "arch-utils.h"
  24 #include "gdbcmd.h"
  25 #include "command.h"
  26 #include "gdb_bfd.h"
  27
  28 #include "elf-bfd.h"
  29
  30 #ifndef GDB_OSABI_DEFAULT
  31 #define GDB_OSABI_DEFAULT GDB_OSABI_UNKNOWN
  32 #endif
  33
  34 /* State for the "set osabi" command.  */
  35 static enum { osabi_auto, osabi_default, osabi_user } user_osabi_state;
  36 static enum gdb_osabi user_selected_osabi;
  37 static const char *gdb_osabi_available_names[GDB_OSABI_INVALID + 3] = {
  38   "auto",
  39   "default",
  40   "none",
  41   NULL
  42 };
  43 static const char *set_osabi_string;
  44
  45 /* Names associated with each osabi.  */
  46
  47 struct osabi_names
  48 {
  49   /* The "pretty" name.  */
  50
  51   const char *pretty;
  52
  53   /* The triplet regexp, or NULL if not known.  */
  54
  55   const char *regexp;
  56 };
  57
  58 /* This table matches the indices assigned to enum gdb_osabi.  Keep
  59    them in sync.  */
  60 static const struct osabi_names gdb_osabi_names[] =
  61 {
  62   { "unknown", NULL },
  63   { "none", NULL },
  64
  65   { "SVR4", NULL },
  66   { "GNU/Hurd", NULL },
  67   { "Solaris", NULL },
  68   { "GNU/Linux", "linux(-gnu[^-]*)?" },
  69   { "FreeBSD", NULL },
  70   { "NetBSD", NULL },
  71   { "OpenBSD", NULL },
  72   { "WindowsCE", NULL },
  73   { "DJGPP", NULL },
  74   { "QNX-Neutrino", NULL },
  75   { "Cygwin", NULL },
  76   { "Windows", NULL },
  77   { "AIX", NULL },
  78   { "DICOS", NULL },
  79   { "Darwin", NULL },
  80   { "OpenVMS", NULL },
  81   { "LynxOS178", NULL },
  82   { "Newlib", NULL },
  83   { "SDE", NULL },
  84   { "PikeOS", NULL },
  85
  86   { "<invalid>", NULL }
  87 };
  88
  89 const char *
  90 gdbarch_osabi_name (enum gdb_osabi osabi)
  91 {
  92   if (osabi >= GDB_OSABI_UNKNOWN && osabi < GDB_OSABI_INVALID)
  93     return gdb_osabi_names[osabi].pretty;
  94
  95   return gdb_osabi_names[GDB_OSABI_INVALID].pretty;
  96 }
  97
  98 /* See osabi.h.  */
  99
 100 const char *
 101 osabi_triplet_regexp (enum gdb_osabi osabi)
 102 {
 103   if (osabi >= GDB_OSABI_UNKNOWN && osabi < GDB_OSABI_INVALID)
 104     return gdb_osabi_names[osabi].regexp;
 105
 106   return gdb_osabi_names[GDB_OSABI_INVALID].regexp;
 107 }
 108
 109 /* Lookup the OS ABI corresponding to the specified target description
 110    string.  */
 111
 112 enum gdb_osabi
 113 osabi_from_tdesc_string (const char *name)
 114 {
 115   int i;
 116
 117   for (i = 0; i < ARRAY_SIZE (gdb_osabi_names); i++)
 118     if (strcmp (name, gdb_osabi_names[i].pretty) == 0)
 119       {
 120         /* See note above: the name table matches the indices assigned
 121            to enum gdb_osabi.  */
 122         enum gdb_osabi osabi = (enum gdb_osabi) i;
 123
 124         if (osabi == GDB_OSABI_INVALID)
 125           return GDB_OSABI_UNKNOWN;
 126         else
 127           return osabi;
 128       }
 129
 130   return GDB_OSABI_UNKNOWN;
 131 }
 132
 133 /* Handler for a given architecture/OS ABI pair.  There should be only
 134    one handler for a given OS ABI each architecture family.  */
 135 struct gdb_osabi_handler
 136 {
 137   struct gdb_osabi_handler *next;
 138   const struct bfd_arch_info *arch_info;
 139   enum gdb_osabi osabi;
 140   void (*init_osabi)(struct gdbarch_info, struct gdbarch *);
 141 };
 142
 143 static struct gdb_osabi_handler *gdb_osabi_handler_list;
 144
 145 void
 146 gdbarch_register_osabi (enum bfd_architecture arch, unsigned long machine,
 147                         enum gdb_osabi osabi,
 148                         void (*init_osabi)(struct gdbarch_info,
 149                                            struct gdbarch *))
 150 {
 151   struct gdb_osabi_handler **handler_p;
 152   const struct bfd_arch_info *arch_info = bfd_lookup_arch (arch, machine);
 153   const char **name_ptr;
 154
 155   /* Registering an OS ABI handler for "unknown" is not allowed.  */
 156   if (osabi == GDB_OSABI_UNKNOWN)
 157     {
 158       internal_error
 159         (_("gdbarch_register_osabi: An attempt to register a handler for "
 160          "OS ABI \"%s\" for architecture %s was made.  The handler will "
 161          "not be registered"),
 162          gdbarch_osabi_name (osabi),
 163          bfd_printable_arch_mach (arch, machine));
 164       return;
 165     }
 166
 167   gdb_assert (arch_info);
 168
 169   for (handler_p = &gdb_osabi_handler_list; *handler_p != NULL;
 170        handler_p = &(*handler_p)->next)
 171     {
 172       if ((*handler_p)->arch_info == arch_info
 173           && (*handler_p)->osabi == osabi)
 174         {
 175           internal_error
 176             (_("gdbarch_register_osabi: A handler for OS ABI \"%s\" "
 177              "has already been registered for architecture %s"),
 178              gdbarch_osabi_name (osabi),
 179              arch_info->printable_name);
 180           /* If user wants to continue, override previous definition.  */
 181           (*handler_p)->init_osabi = init_osabi;
 182           return;
 183         }
 184     }
 185
 186   (*handler_p) = XNEW (struct gdb_osabi_handler);
 187   (*handler_p)->next = NULL;
 188   (*handler_p)->arch_info = arch_info;
 189   (*handler_p)->osabi = osabi;
 190   (*handler_p)->init_osabi = init_osabi;
 191
 192   /* Add this OS ABI to the list of enum values for "set osabi", if it isn't
 193      already there.  */
 194   for (name_ptr = gdb_osabi_available_names; *name_ptr; name_ptr ++)
 195     {
 196       if (*name_ptr == gdbarch_osabi_name (osabi))
 197         return;
 198     }
 199   *name_ptr++ = gdbarch_osabi_name (osabi);
 200   *name_ptr = NULL;
 201 }
 202 \f
 203
 204 /* Sniffer to find the OS ABI for a given file's architecture and flavour.
 205    It is legal to have multiple sniffers for each arch/flavour pair, to
 206    disambiguate one OS's a.out from another, for example.  The first sniffer
 207    to return something other than GDB_OSABI_UNKNOWN wins, so a sniffer should
 208    be careful to claim a file only if it knows for sure what it is.  */
 209 struct gdb_osabi_sniffer
 210 {
 211   struct gdb_osabi_sniffer *next;
 212   enum bfd_architecture arch;   /* bfd_arch_unknown == wildcard */
 213   enum bfd_flavour flavour;
 214   enum gdb_osabi (*sniffer)(bfd *);
 215 };
 216
 217 static struct gdb_osabi_sniffer *gdb_osabi_sniffer_list;
 218
 219 void
 220 gdbarch_register_osabi_sniffer (enum bfd_architecture arch,
 221                                 enum bfd_flavour flavour,
 222                                 enum gdb_osabi (*sniffer_fn)(bfd *))
 223 {
 224   struct gdb_osabi_sniffer *sniffer;
 225
 226   sniffer = XNEW (struct gdb_osabi_sniffer);
 227   sniffer->arch = arch;
 228   sniffer->flavour = flavour;
 229   sniffer->sniffer = sniffer_fn;
 230
 231   sniffer->next = gdb_osabi_sniffer_list;
 232   gdb_osabi_sniffer_list = sniffer;
 233 }
 234 \f
 235
 236 enum gdb_osabi
 237 gdbarch_lookup_osabi (bfd *abfd)
 238 {
 239   struct gdb_osabi_sniffer *sniffer;
 240   enum gdb_osabi osabi, match;
 241   int match_specific;
 242
 243   /* If we aren't in "auto" mode, return the specified OS ABI.  */
 244   if (user_osabi_state == osabi_user)
 245     return user_selected_osabi;
 246
 247   /* If we don't have a binary, just return unknown.  The caller may
 248      have other sources the OSABI can be extracted from, e.g., the
 249      target description.  */
 250   if (abfd == NULL)
 251     return GDB_OSABI_UNKNOWN;
 252
 253   match = GDB_OSABI_UNKNOWN;
 254   match_specific = 0;
 255
 256   for (sniffer = gdb_osabi_sniffer_list; sniffer != NULL;
 257        sniffer = sniffer->next)
 258     {
 259       if ((sniffer->arch == bfd_arch_unknown /* wildcard */
 260            || sniffer->arch == bfd_get_arch (abfd))
 261           && sniffer->flavour == bfd_get_flavour (abfd))
 262         {
 263           osabi = (*sniffer->sniffer) (abfd);
 264           if (osabi < GDB_OSABI_UNKNOWN || osabi >= GDB_OSABI_INVALID)
 265             {
 266               internal_error
 267                 (_("gdbarch_lookup_osabi: invalid OS ABI (%d) from sniffer "
 268                  "for architecture %s flavour %d"),
 269                  (int) osabi,
 270                  bfd_printable_arch_mach (bfd_get_arch (abfd), 0),
 271                  (int) bfd_get_flavour (abfd));
 272             }
 273           else if (osabi != GDB_OSABI_UNKNOWN)
 274             {
 275               /* A specific sniffer always overrides a generic sniffer.
 276                  Croak on multiple match if the two matches are of the
 277                  same class.  If the user wishes to continue, we'll use
 278                  the first match.  */
 279               if (match != GDB_OSABI_UNKNOWN)
 280                 {
 281                   if ((match_specific && sniffer->arch != bfd_arch_unknown)
 282                    || (!match_specific && sniffer->arch == bfd_arch_unknown))
 283                     {
 284                       internal_error
 285                         (_("gdbarch_lookup_osabi: multiple %sspecific OS ABI "
 286                          "match for architecture %s flavour %d: first "
 287                          "match \"%s\", second match \"%s\""),
 288                          match_specific ? "" : "non-",
 289                          bfd_printable_arch_mach (bfd_get_arch (abfd), 0),
 290                          (int) bfd_get_flavour (abfd),
 291                          gdbarch_osabi_name (match),
 292                          gdbarch_osabi_name (osabi));
 293                     }
 294                   else if (sniffer->arch != bfd_arch_unknown)
 295                     {
 296                       match = osabi;
 297                       match_specific = 1;
 298                     }
 299                 }
 300               else
 301                 {
 302                   match = osabi;
 303                   if (sniffer->arch != bfd_arch_unknown)
 304                     match_specific = 1;
 305                 }
 306             }
 307         }
 308     }
 309
 310   return match;
 311 }
 312
 313
 314 /* Return non-zero if architecture A can run code written for
 315    architecture B.  */
 316 static int
 317 can_run_code_for (const struct bfd_arch_info *a, const struct bfd_arch_info *b)
 318 {
 319   /* BFD's 'A->compatible (A, B)' functions return zero if A and B are
 320      incompatible.  But if they are compatible, it returns the 'more
 321      featureful' of the two arches.  That is, if A can run code
 322      written for B, but B can't run code written for A, then it'll
 323      return A.
 324
 325      struct bfd_arch_info objects are singletons: that is, there's
 326      supposed to be exactly one instance for a given machine.  So you
 327      can tell whether two are equivalent by comparing pointers.  */
 328   return (a == b || a->compatible (a, b) == a);
 329 }
 330
 331 /* Return OS ABI handler for INFO.  */
 332
 333 static struct gdb_osabi_handler *
 334 gdbarch_osabi_handler (struct gdbarch_info info)
 335 {
 336   struct gdb_osabi_handler *handler;
 337
 338   gdb_assert (info.osabi != GDB_OSABI_UNKNOWN);
 339
 340   for (handler = gdb_osabi_handler_list; handler != NULL;
 341        handler = handler->next)
 342     {
 343       if (handler->osabi != info.osabi)
 344         continue;
 345
 346       /* If the architecture described by ARCH_INFO can run code for
 347          the architecture we registered the handler for, then the
 348          handler is applicable.  Note, though, that if the handler is
 349          for an architecture that is a superset of ARCH_INFO, we can't
 350          use that --- it would be perfectly correct for it to install
 351          gdbarch methods that refer to registers / instructions /
 352          other facilities ARCH_INFO doesn't have.
 353
 354          NOTE: kettenis/20021027: There may be more than one machine
 355          type that is compatible with the desired machine type.  Right
 356          now we simply return the first match, which is fine for now.
 357          However, we might want to do something smarter in the future.  */
 358       /* NOTE: cagney/2003-10-23: The code for "a can_run_code_for b"
 359          is implemented using BFD's compatible method (a->compatible
 360          (b) == a -- the lowest common denominator between a and b is
 361          a).  That method's definition of compatible may not be as you
 362          expect.  For instance the test "amd64 can run code for i386"
 363          (or more generally "64-bit ISA can run code for the 32-bit
 364          ISA").  BFD doesn't normally consider 32-bit and 64-bit
 365          "compatible" so it doesn't succeed.  */
 366       if (can_run_code_for (info.bfd_arch_info, handler->arch_info))
 367         return handler;
 368     }
 369
 370   return nullptr;
 371 }
 372
 373 /* See osabi.h.  */
 374
 375 bool
 376 has_gdb_osabi_handler (struct gdbarch_info info)
 377 {
 378   return gdbarch_osabi_handler (info) != nullptr;
 379 }
 380
 381 void
 382 gdbarch_init_osabi (struct gdbarch_info info, struct gdbarch *gdbarch)
 383 {
 384   struct gdb_osabi_handler *handler;
 385
 386   gdb_assert (info.osabi != GDB_OSABI_UNKNOWN);
 387   handler = gdbarch_osabi_handler (info);
 388
 389   if (handler != nullptr)
 390     {
 391       (*handler->init_osabi) (info, gdbarch);
 392       return;
 393     }
 394
 395   if (info.osabi == GDB_OSABI_NONE)
 396     {
 397       /* Don't complain about no OSABI.  Assume the user knows
 398          what they are doing.  */
 399       return;
 400     }
 401
 402   warning
 403     ("A handler for the OS ABI \"%s\" is not built into this configuration\n"
 404      "of GDB.  Attempting to continue with the default %s settings.\n",
 405      gdbarch_osabi_name (info.osabi),
 406      info.bfd_arch_info->printable_name);
 407 }
 408 \f
 409 /* Limit on the amount of data to be read.  */
 410 #define MAX_NOTESZ      128
 411
 412 /* Return non-zero if NOTE matches NAME, DESCSZ and TYPE.  If
 413    *SECTSIZE is non-zero, then this reads that many bytes from
 414    the start of the section and clears *SECTSIZE.  */
 415
 416 static int
 417 check_note (bfd *abfd, asection *sect, char *note, unsigned int *sectsize,
 418             const char *name, unsigned long descsz, unsigned long type)
 419 {
 420   unsigned long notesz;
 421
 422   if (*sectsize)
 423     {
 424       if (!bfd_get_section_contents (abfd, sect, note, 0, *sectsize))
 425         return 0;
 426       *sectsize = 0;
 427     }
 428
 429   /* Calculate the size of this note.  */
 430   notesz = strlen (name) + 1;
 431   notesz = ((notesz + 3) & ~3);
 432   notesz += descsz;
 433   notesz = ((notesz + 3) & ~3);
 434
 435   /* If this assertion triggers, increase MAX_NOTESZ.  */
 436   gdb_assert (notesz <= MAX_NOTESZ);
 437
 438   /* Check whether SECT is big enough to contain the complete note.  */
 439   if (notesz > bfd_section_size (sect))
 440     return 0;
 441
 442   /* Check the note name.  */
 443   if (bfd_h_get_32 (abfd, note) != (strlen (name) + 1)
 444       || strcmp (note + 12, name) != 0)
 445     return 0;
 446
 447   /* Check the descriptor size.  */
 448   if (bfd_h_get_32 (abfd, note + 4) != descsz)
 449     return 0;
 450
 451   /* Check the note type.  */
 452   if (bfd_h_get_32 (abfd, note + 8) != type)
 453     return 0;
 454
 455   return 1;
 456 }
 457
 458 /* Generic sniffer for ELF flavoured files.  */
 459
 460 void
 461 generic_elf_osabi_sniff_abi_tag_sections (bfd *abfd, asection *sect,
 462                                           enum gdb_osabi *osabi)
 463 {
 464   const char *name;
 465   unsigned int sectsize;
 466
 467   name = bfd_section_name (sect);
 468   sectsize = bfd_section_size (sect);
 469
 470   /* Limit the amount of data to read.  */
 471   if (sectsize > MAX_NOTESZ)
 472     sectsize = MAX_NOTESZ;
 473
 474   /* We lazily read the section data here.  Since we use
 475      BFD_DECOMPRESS, we can't use bfd_get_section_contents on a
 476      compressed section.  But, since note sections are not compressed,
 477      deferring the reading until we recognize the section avoids any
 478      error.  */
 479   char note[MAX_NOTESZ];
 480
 481   /* .note.ABI-tag notes, used by GNU/Linux and FreeBSD.  */
 482   if (strcmp (name, ".note.ABI-tag") == 0)
 483     {
 484       /* GNU.  */
 485       if (check_note (abfd, sect, note, &sectsize, "GNU", 16, NT_GNU_ABI_TAG))
 486         {
 487           unsigned int abi_tag = bfd_h_get_32 (abfd, note + 16);
 488
 489           switch (abi_tag)
 490             {
 491             case GNU_ABI_TAG_LINUX:
 492               *osabi = GDB_OSABI_LINUX;
 493               break;
 494
 495             case GNU_ABI_TAG_HURD:
 496               *osabi = GDB_OSABI_HURD;
 497               break;
 498
 499             case GNU_ABI_TAG_SOLARIS:
 500               *osabi = GDB_OSABI_SOLARIS;
 501               break;
 502
 503             case GNU_ABI_TAG_FREEBSD:
 504               *osabi = GDB_OSABI_FREEBSD;
 505               break;
 506
 507             case GNU_ABI_TAG_NETBSD:
 508               *osabi = GDB_OSABI_NETBSD;
 509               break;
 510
 511             default:
 512               warning (_("GNU ABI tag value %u unrecognized."), abi_tag);
 513               break;
 514             }
 515           return;
 516         }
 517
 518       /* FreeBSD.  */
 519       if (check_note (abfd, sect, note, &sectsize, "FreeBSD", 4,
 520                       NT_FREEBSD_ABI_TAG))
 521         {
 522           /* There is no need to check the version yet.  */
 523           *osabi = GDB_OSABI_FREEBSD;
 524           return;
 525         }
 526
 527       return;
 528     }
 529
 530   /* .note.netbsd.ident notes, used by NetBSD.  */
 531   if (strcmp (name, ".note.netbsd.ident") == 0
 532       && check_note (abfd, sect, note, &sectsize, "NetBSD", 4, NT_NETBSD_IDENT))
 533     {
 534       /* There is no need to check the version yet.  */
 535       *osabi = GDB_OSABI_NETBSD;
 536       return;
 537     }
 538
 539   /* .note.openbsd.ident notes, used by OpenBSD.  */
 540   if (strcmp (name, ".note.openbsd.ident") == 0
 541       && check_note (abfd, sect, note, &sectsize, "OpenBSD", 4,
 542                      NT_OPENBSD_IDENT))
 543     {
 544       /* There is no need to check the version yet.  */
 545       *osabi = GDB_OSABI_OPENBSD;
 546       return;
 547     }
 548
 549   /* .note.netbsdcore.procinfo notes, used by NetBSD.  */
 550   if (strcmp (name, ".note.netbsdcore.procinfo") == 0)
 551     {
 552       *osabi = GDB_OSABI_NETBSD;
 553       return;
 554     }
 555 }
 556
 557 static enum gdb_osabi
 558 generic_elf_osabi_sniffer (bfd *abfd)
 559 {
 560   unsigned int elfosabi;
 561   enum gdb_osabi osabi = GDB_OSABI_UNKNOWN;
 562
 563   elfosabi = elf_elfheader (abfd)->e_ident[EI_OSABI];
 564
 565   switch (elfosabi)
 566     {
 567     case ELFOSABI_NONE:
 568     case ELFOSABI_GNU:
 569     case ELFOSABI_HPUX:
 570       /* When the EI_OSABI field in the ELF header is ELFOSABI_NONE
 571          (0), then the ELF structures in the file are conforming to
 572          the base specification for that machine (there are no
 573          OS-specific extensions).  In order to determine the real OS
 574          in use, we must look for OS-specific notes.
 575
 576          The same applies for ELFOSABI_GNU: this can mean GNU/Hurd,
 577          GNU/Linux, and possibly more.  */
 578
 579       /* And likewise ELFOSABI_HPUX.  For some reason the default
 580          value for the EI_OSABI field is ELFOSABI_HPUX for all PA-RISC
 581          targets (with the exception of GNU/Linux).  */
 582       for (asection *sect : gdb_bfd_sections (abfd))
 583         generic_elf_osabi_sniff_abi_tag_sections (abfd, sect, &osabi);
 584       break;
 585
 586     case ELFOSABI_FREEBSD:
 587       osabi = GDB_OSABI_FREEBSD;
 588       break;
 589
 590     case ELFOSABI_NETBSD:
 591       osabi = GDB_OSABI_NETBSD;
 592       break;
 593
 594     case ELFOSABI_SOLARIS:
 595       osabi = GDB_OSABI_SOLARIS;
 596       break;
 597
 598     case ELFOSABI_OPENVMS:
 599       osabi = GDB_OSABI_OPENVMS;
 600       break;
 601     }
 602
 603   if (osabi == GDB_OSABI_UNKNOWN)
 604     {
 605       /* The FreeBSD folks have been naughty; they stored the string
 606          "FreeBSD" in the padding of the e_ident field of the ELF
 607          header to "brand" their ELF binaries in FreeBSD 3.x.  */
 608       if (memcmp (&elf_elfheader (abfd)->e_ident[8],
 609                   "FreeBSD", sizeof ("FreeBSD")) == 0)
 610         osabi = GDB_OSABI_FREEBSD;
 611     }
 612
 613   return osabi;
 614 }
 615 \f
 616 static void
 617 set_osabi (const char *args, int from_tty, struct cmd_list_element *c)
 618 {
 619   if (strcmp (set_osabi_string, "auto") == 0)
 620     user_osabi_state = osabi_auto;
 621   else if (strcmp (set_osabi_string, "default") == 0)
 622     {
 623       user_selected_osabi = GDB_OSABI_DEFAULT;
 624       user_osabi_state = osabi_user;
 625     }
 626   else
 627     {
 628       int i;
 629
 630       for (i = 1; i < GDB_OSABI_INVALID; i++)
 631         {
 632           enum gdb_osabi osabi = (enum gdb_osabi) i;
 633
 634           if (strcmp (set_osabi_string, gdbarch_osabi_name (osabi)) == 0)
 635             {
 636               user_selected_osabi = osabi;
 637               user_osabi_state = osabi_user;
 638               break;
 639             }
 640         }
 641       if (i == GDB_OSABI_INVALID)
 642         internal_error (_("Invalid OS ABI \"%s\" passed to command handler."),
 643                         set_osabi_string);
 644     }
 645
 646   /* NOTE: At some point (true multiple architectures) we'll need to be more
 647      graceful here.  */
 648   gdbarch_info info;
 649   if (! gdbarch_update_p (info))
 650     internal_error (_("Updating OS ABI failed."));
 651 }
 652
 653 static void
 654 show_osabi (struct ui_file *file, int from_tty, struct cmd_list_element *c,
 655             const char *value)
 656 {
 657   if (user_osabi_state == osabi_auto)
 658     gdb_printf (file,
 659                 _("The current OS ABI is \"auto\" "
 660                   "(currently \"%s\").\n"),
 661                 gdbarch_osabi_name (gdbarch_osabi (get_current_arch ())));
 662   else
 663     gdb_printf (file, _("The current OS ABI is \"%s\".\n"),
 664                 gdbarch_osabi_name (user_selected_osabi));
 665
 666   if (GDB_OSABI_DEFAULT != GDB_OSABI_UNKNOWN)
 667     gdb_printf (file, _("The default OS ABI is \"%s\".\n"),
 668                 gdbarch_osabi_name (GDB_OSABI_DEFAULT));
 669 }
 670
 671 void _initialize_gdb_osabi ();
 672 void
 673 _initialize_gdb_osabi ()
 674 {
 675   if (strcmp (gdb_osabi_names[GDB_OSABI_INVALID].pretty, "<invalid>") != 0)
 676     internal_error
 677       (_("_initialize_gdb_osabi: gdb_osabi_names[] is inconsistent"));
 678
 679   /* Register a generic sniffer for ELF flavoured files.  */
 680   gdbarch_register_osabi_sniffer (bfd_arch_unknown,
 681                                   bfd_target_elf_flavour,
 682                                   generic_elf_osabi_sniffer);
 683
 684   /* Register the "set osabi" command.  */
 685   user_osabi_state = osabi_auto;
 686   set_osabi_string = gdb_osabi_available_names[0];
 687   gdb_assert (strcmp (set_osabi_string, "auto") == 0);
 688   add_setshow_enum_cmd ("osabi", class_support, gdb_osabi_available_names,
 689                         &set_osabi_string,
 690                         _("Set OS ABI of target."),
 691                         _("Show OS ABI of target."),
 692                         NULL, set_osabi, show_osabi,
 693                         &setlist, &showlist);
 694 }