gdb/osabi.c

   1 /* OS ABI variant handling for GDB.
   2
   3    Copyright (C) 2001-2020 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
  27 #include "elf-bfd.h"
  28
  29 #ifndef GDB_OSABI_DEFAULT
  30 #define GDB_OSABI_DEFAULT GDB_OSABI_UNKNOWN
  31 #endif
  32
  33 /* State for the "set osabi" command.  */
  34 static enum { osabi_auto, osabi_default, osabi_user } user_osabi_state;
  35 static enum gdb_osabi user_selected_osabi;
  36 static const char *gdb_osabi_available_names[GDB_OSABI_INVALID + 3] = {
  37   "auto",
  38   "default",
  39   "none",
  40   NULL
  41 };
  42 static const char *set_osabi_string;
  43
  44 /* Names associated with each osabi.  */
  45
  46 struct osabi_names
  47 {
  48   /* The "pretty" name.  */
  49
  50   const char *pretty;
  51
  52   /* The triplet regexp, or NULL if not known.  */
  53
  54   const char *regexp;
  55 };
  56
  57 /* This table matches the indices assigned to enum gdb_osabi.  Keep
  58    them in sync.  */
  59 static const struct osabi_names gdb_osabi_names[] =
  60 {
  61   { "unknown", NULL },
  62   { "none", NULL },
  63
  64   { "SVR4", NULL },
  65   { "GNU/Hurd", NULL },
  66   { "Solaris", NULL },
  67   { "GNU/Linux", "linux(-gnu[^-]*)?" },
  68   { "FreeBSD", NULL },
  69   { "NetBSD", NULL },
  70   { "OpenBSD", NULL },
  71   { "WindowsCE", NULL },
  72   { "DJGPP", NULL },
  73   { "QNX-Neutrino", NULL },
  74   { "Cygwin", NULL },
  75   { "Windows", NULL },
  76   { "AIX", NULL },
  77   { "DICOS", NULL },
  78   { "Darwin", NULL },
  79   { "Symbian", 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         (__FILE__, __LINE__,
 160          _("gdbarch_register_osabi: An attempt to register a handler for "
 161          "OS ABI \"%s\" for architecture %s was made.  The handler will "
 162          "not be registered"),
 163          gdbarch_osabi_name (osabi),
 164          bfd_printable_arch_mach (arch, machine));
 165       return;
 166     }
 167
 168   gdb_assert (arch_info);
 169
 170   for (handler_p = &gdb_osabi_handler_list; *handler_p != NULL;
 171        handler_p = &(*handler_p)->next)
 172     {
 173       if ((*handler_p)->arch_info == arch_info
 174           && (*handler_p)->osabi == osabi)
 175         {
 176           internal_error
 177             (__FILE__, __LINE__,
 178              _("gdbarch_register_osabi: A handler for OS ABI \"%s\" "
 179              "has already been registered for architecture %s"),
 180              gdbarch_osabi_name (osabi),
 181              arch_info->printable_name);
 182           /* If user wants to continue, override previous definition.  */
 183           (*handler_p)->init_osabi = init_osabi;
 184           return;
 185         }
 186     }
 187
 188   (*handler_p) = XNEW (struct gdb_osabi_handler);
 189   (*handler_p)->next = NULL;
 190   (*handler_p)->arch_info = arch_info;
 191   (*handler_p)->osabi = osabi;
 192   (*handler_p)->init_osabi = init_osabi;
 193
 194   /* Add this OS ABI to the list of enum values for "set osabi", if it isn't
 195      already there.  */
 196   for (name_ptr = gdb_osabi_available_names; *name_ptr; name_ptr ++)
 197     {
 198       if (*name_ptr == gdbarch_osabi_name (osabi))
 199         return;
 200     }
 201   *name_ptr++ = gdbarch_osabi_name (osabi);
 202   *name_ptr = NULL;
 203 }
 204 \f
 205
 206 /* Sniffer to find the OS ABI for a given file's architecture and flavour.
 207    It is legal to have multiple sniffers for each arch/flavour pair, to
 208    disambiguate one OS's a.out from another, for example.  The first sniffer
 209    to return something other than GDB_OSABI_UNKNOWN wins, so a sniffer should
 210    be careful to claim a file only if it knows for sure what it is.  */
 211 struct gdb_osabi_sniffer
 212 {
 213   struct gdb_osabi_sniffer *next;
 214   enum bfd_architecture arch;   /* bfd_arch_unknown == wildcard */
 215   enum bfd_flavour flavour;
 216   enum gdb_osabi (*sniffer)(bfd *);
 217 };
 218
 219 static struct gdb_osabi_sniffer *gdb_osabi_sniffer_list;
 220
 221 void
 222 gdbarch_register_osabi_sniffer (enum bfd_architecture arch,
 223                                 enum bfd_flavour flavour,
 224                                 enum gdb_osabi (*sniffer_fn)(bfd *))
 225 {
 226   struct gdb_osabi_sniffer *sniffer;
 227
 228   sniffer = XNEW (struct gdb_osabi_sniffer);
 229   sniffer->arch = arch;
 230   sniffer->flavour = flavour;
 231   sniffer->sniffer = sniffer_fn;
 232
 233   sniffer->next = gdb_osabi_sniffer_list;
 234   gdb_osabi_sniffer_list = sniffer;
 235 }
 236 \f
 237
 238 enum gdb_osabi
 239 gdbarch_lookup_osabi (bfd *abfd)
 240 {
 241   struct gdb_osabi_sniffer *sniffer;
 242   enum gdb_osabi osabi, match;
 243   int match_specific;
 244
 245   /* If we aren't in "auto" mode, return the specified OS ABI.  */
 246   if (user_osabi_state == osabi_user)
 247     return user_selected_osabi;
 248
 249   /* If we don't have a binary, just return unknown.  The caller may
 250      have other sources the OSABI can be extracted from, e.g., the
 251      target description.  */
 252   if (abfd == NULL)
 253     return GDB_OSABI_UNKNOWN;
 254
 255   match = GDB_OSABI_UNKNOWN;
 256   match_specific = 0;
 257
 258   for (sniffer = gdb_osabi_sniffer_list; sniffer != NULL;
 259        sniffer = sniffer->next)
 260     {
 261       if ((sniffer->arch == bfd_arch_unknown /* wildcard */
 262            || sniffer->arch == bfd_get_arch (abfd))
 263           && sniffer->flavour == bfd_get_flavour (abfd))
 264         {
 265           osabi = (*sniffer->sniffer) (abfd);
 266           if (osabi < GDB_OSABI_UNKNOWN || osabi >= GDB_OSABI_INVALID)
 267             {
 268               internal_error
 269                 (__FILE__, __LINE__,
 270                  _("gdbarch_lookup_osabi: invalid OS ABI (%d) from sniffer "
 271                  "for architecture %s flavour %d"),
 272                  (int) osabi,
 273                  bfd_printable_arch_mach (bfd_get_arch (abfd), 0),
 274                  (int) bfd_get_flavour (abfd));
 275             }
 276           else if (osabi != GDB_OSABI_UNKNOWN)
 277             {
 278               /* A specific sniffer always overrides a generic sniffer.
 279                  Croak on multiple match if the two matches are of the
 280                  same class.  If the user wishes to continue, we'll use
 281                  the first match.  */
 282               if (match != GDB_OSABI_UNKNOWN)
 283                 {
 284                   if ((match_specific && sniffer->arch != bfd_arch_unknown)
 285                    || (!match_specific && sniffer->arch == bfd_arch_unknown))
 286                     {
 287                       internal_error
 288                         (__FILE__, __LINE__,
 289                          _("gdbarch_lookup_osabi: multiple %sspecific OS ABI "
 290                          "match for architecture %s flavour %d: first "
 291                          "match \"%s\", second match \"%s\""),
 292                          match_specific ? "" : "non-",
 293                          bfd_printable_arch_mach (bfd_get_arch (abfd), 0),
 294                          (int) bfd_get_flavour (abfd),
 295                          gdbarch_osabi_name (match),
 296                          gdbarch_osabi_name (osabi));
 297                     }
 298                   else if (sniffer->arch != bfd_arch_unknown)
 299                     {
 300                       match = osabi;
 301                       match_specific = 1;
 302                     }
 303                 }
 304               else
 305                 {
 306                   match = osabi;
 307                   if (sniffer->arch != bfd_arch_unknown)
 308                     match_specific = 1;
 309                 }
 310             }
 311         }
 312     }
 313
 314   return match;
 315 }
 316
 317
 318 /* Return non-zero if architecture A can run code written for
 319    architecture B.  */
 320 static int
 321 can_run_code_for (const struct bfd_arch_info *a, const struct bfd_arch_info *b)
 322 {
 323   /* BFD's 'A->compatible (A, B)' functions return zero if A and B are
 324      incompatible.  But if they are compatible, it returns the 'more
 325      featureful' of the two arches.  That is, if A can run code
 326      written for B, but B can't run code written for A, then it'll
 327      return A.
 328
 329      struct bfd_arch_info objects are singletons: that is, there's
 330      supposed to be exactly one instance for a given machine.  So you
 331      can tell whether two are equivalent by comparing pointers.  */
 332   return (a == b || a->compatible (a, b) == a);
 333 }
 334
 335
 336 void
 337 gdbarch_init_osabi (struct gdbarch_info info, struct gdbarch *gdbarch)
 338 {
 339   struct gdb_osabi_handler *handler;
 340
 341   gdb_assert (info.osabi != GDB_OSABI_UNKNOWN);
 342
 343   for (handler = gdb_osabi_handler_list; handler != NULL;
 344        handler = handler->next)
 345     {
 346       if (handler->osabi != info.osabi)
 347         continue;
 348
 349       /* If the architecture described by ARCH_INFO can run code for
 350          the architecture we registered the handler for, then the
 351          handler is applicable.  Note, though, that if the handler is
 352          for an architecture that is a superset of ARCH_INFO, we can't
 353          use that --- it would be perfectly correct for it to install
 354          gdbarch methods that refer to registers / instructions /
 355          other facilities ARCH_INFO doesn't have.
 356
 357          NOTE: kettenis/20021027: There may be more than one machine
 358          type that is compatible with the desired machine type.  Right
 359          now we simply return the first match, which is fine for now.
 360          However, we might want to do something smarter in the future.  */
 361       /* NOTE: cagney/2003-10-23: The code for "a can_run_code_for b"
 362          is implemented using BFD's compatible method (a->compatible
 363          (b) == a -- the lowest common denominator between a and b is
 364          a).  That method's definition of compatible may not be as you
 365          expect.  For instance the test "amd64 can run code for i386"
 366          (or more generally "64-bit ISA can run code for the 32-bit
 367          ISA").  BFD doesn't normally consider 32-bit and 64-bit
 368          "compatible" so it doesn't succeed.  */
 369       if (can_run_code_for (info.bfd_arch_info, handler->arch_info))
 370         {
 371           (*handler->init_osabi) (info, gdbarch);
 372           return;
 373         }
 374     }
 375
 376   if (info.osabi == GDB_OSABI_NONE)
 377     {
 378       /* Don't complain about no OSABI.  Assume the user knows
 379          what they are doing.  */
 380       return;
 381     }
 382
 383   warning
 384     ("A handler for the OS ABI \"%s\" is not built into this configuration\n"
 385      "of GDB.  Attempting to continue with the default %s settings.\n",
 386      gdbarch_osabi_name (info.osabi),
 387      info.bfd_arch_info->printable_name);
 388 }
 389 \f
 390 /* Limit on the amount of data to be read.  */
 391 #define MAX_NOTESZ      128
 392
 393 /* Return non-zero if NOTE matches NAME, DESCSZ and TYPE.  If
 394    *SECTSIZE is non-zero, then this reads that many bytes from
 395    the start of the section and clears *SECTSIZE.  */
 396
 397 static int
 398 check_note (bfd *abfd, asection *sect, char *note, unsigned int *sectsize,
 399             const char *name, unsigned long descsz, unsigned long type)
 400 {
 401   unsigned long notesz;
 402
 403   if (*sectsize)
 404     {
 405       if (!bfd_get_section_contents (abfd, sect, note, 0, *sectsize))
 406         return 0;
 407       *sectsize = 0;
 408     }
 409
 410   /* Calculate the size of this note.  */
 411   notesz = strlen (name) + 1;
 412   notesz = ((notesz + 3) & ~3);
 413   notesz += descsz;
 414   notesz = ((notesz + 3) & ~3);
 415
 416   /* If this assertion triggers, increase MAX_NOTESZ.  */
 417   gdb_assert (notesz <= MAX_NOTESZ);
 418
 419   /* Check whether SECT is big enough to contain the complete note.  */
 420   if (notesz > bfd_section_size (sect))
 421     return 0;
 422
 423   /* Check the note name.  */
 424   if (bfd_h_get_32 (abfd, note) != (strlen (name) + 1)
 425       || strcmp (note + 12, name) != 0)
 426     return 0;
 427
 428   /* Check the descriptor size.  */
 429   if (bfd_h_get_32 (abfd, note + 4) != descsz)
 430     return 0;
 431
 432   /* Check the note type.  */
 433   if (bfd_h_get_32 (abfd, note + 8) != type)
 434     return 0;
 435
 436   return 1;
 437 }
 438
 439 /* Generic sniffer for ELF flavoured files.  */
 440
 441 void
 442 generic_elf_osabi_sniff_abi_tag_sections (bfd *abfd, asection *sect, void *obj)
 443 {
 444   enum gdb_osabi *osabi = (enum gdb_osabi *) obj;
 445   const char *name;
 446   unsigned int sectsize;
 447   char *note;
 448
 449   name = bfd_section_name (sect);
 450   sectsize = bfd_section_size (sect);
 451
 452   /* Limit the amount of data to read.  */
 453   if (sectsize > MAX_NOTESZ)
 454     sectsize = MAX_NOTESZ;
 455
 456   /* We lazily read the section data here.  Since we use
 457      BFD_DECOMPRESS, we can't use bfd_get_section_contents on a
 458      compressed section.  But, since note sections are not compressed,
 459      deferring the reading until we recognize the section avoids any
 460      error.  */
 461   note = (char *) alloca (sectsize);
 462
 463   /* .note.ABI-tag notes, used by GNU/Linux and FreeBSD.  */
 464   if (strcmp (name, ".note.ABI-tag") == 0)
 465     {
 466       /* GNU.  */
 467       if (check_note (abfd, sect, note, &sectsize, "GNU", 16, NT_GNU_ABI_TAG))
 468         {
 469           unsigned int abi_tag = bfd_h_get_32 (abfd, note + 16);
 470
 471           switch (abi_tag)
 472             {
 473             case GNU_ABI_TAG_LINUX:
 474               *osabi = GDB_OSABI_LINUX;
 475               break;
 476
 477             case GNU_ABI_TAG_HURD:
 478               *osabi = GDB_OSABI_HURD;
 479               break;
 480
 481             case GNU_ABI_TAG_SOLARIS:
 482               *osabi = GDB_OSABI_SOLARIS;
 483               break;
 484
 485             case GNU_ABI_TAG_FREEBSD:
 486               *osabi = GDB_OSABI_FREEBSD;
 487               break;
 488
 489             case GNU_ABI_TAG_NETBSD:
 490               *osabi = GDB_OSABI_NETBSD;
 491               break;
 492
 493             default:
 494               warning (_("GNU ABI tag value %u unrecognized."), abi_tag);
 495               break;
 496             }
 497           return;
 498         }
 499
 500       /* FreeBSD.  */
 501       if (check_note (abfd, sect, note, &sectsize, "FreeBSD", 4,
 502                       NT_FREEBSD_ABI_TAG))
 503         {
 504           /* There is no need to check the version yet.  */
 505           *osabi = GDB_OSABI_FREEBSD;
 506           return;
 507         }
 508
 509       return;
 510     }
 511
 512   /* .note.netbsd.ident notes, used by NetBSD.  */
 513   if (strcmp (name, ".note.netbsd.ident") == 0
 514       && check_note (abfd, sect, note, &sectsize, "NetBSD", 4, NT_NETBSD_IDENT))
 515     {
 516       /* There is no need to check the version yet.  */
 517       *osabi = GDB_OSABI_NETBSD;
 518       return;
 519     }
 520
 521   /* .note.openbsd.ident notes, used by OpenBSD.  */
 522   if (strcmp (name, ".note.openbsd.ident") == 0
 523       && check_note (abfd, sect, note, &sectsize, "OpenBSD", 4,
 524                      NT_OPENBSD_IDENT))
 525     {
 526       /* There is no need to check the version yet.  */
 527       *osabi = GDB_OSABI_OPENBSD;
 528       return;
 529     }
 530
 531   /* .note.netbsdcore.procinfo notes, used by NetBSD.  */
 532   if (strcmp (name, ".note.netbsdcore.procinfo") == 0)
 533     {
 534       *osabi = GDB_OSABI_NETBSD;
 535       return;
 536     }
 537 }
 538
 539 static enum gdb_osabi
 540 generic_elf_osabi_sniffer (bfd *abfd)
 541 {
 542   unsigned int elfosabi;
 543   enum gdb_osabi osabi = GDB_OSABI_UNKNOWN;
 544
 545   elfosabi = elf_elfheader (abfd)->e_ident[EI_OSABI];
 546
 547   switch (elfosabi)
 548     {
 549     case ELFOSABI_NONE:
 550     case ELFOSABI_GNU:
 551     case ELFOSABI_HPUX:
 552       /* When the EI_OSABI field in the ELF header is ELFOSABI_NONE
 553          (0), then the ELF structures in the file are conforming to
 554          the base specification for that machine (there are no
 555          OS-specific extensions).  In order to determine the real OS
 556          in use, we must look for OS-specific notes.
 557
 558          The same applies for ELFOSABI_GNU: this can mean GNU/Hurd,
 559          GNU/Linux, and possibly more.  */
 560
 561       /* And likewise ELFOSABI_HPUX.  For some reason the default
 562          value for the EI_OSABI field is ELFOSABI_HPUX for all PA-RISC
 563          targets (with the exception of GNU/Linux).  */
 564       bfd_map_over_sections (abfd,
 565                              generic_elf_osabi_sniff_abi_tag_sections,
 566                              &osabi);
 567       break;
 568
 569     case ELFOSABI_FREEBSD:
 570       osabi = GDB_OSABI_FREEBSD;
 571       break;
 572
 573     case ELFOSABI_NETBSD:
 574       osabi = GDB_OSABI_NETBSD;
 575       break;
 576
 577     case ELFOSABI_SOLARIS:
 578       osabi = GDB_OSABI_SOLARIS;
 579       break;
 580
 581     case ELFOSABI_OPENVMS:
 582       osabi = GDB_OSABI_OPENVMS;
 583       break;
 584     }
 585
 586   if (osabi == GDB_OSABI_UNKNOWN)
 587     {
 588       /* The FreeBSD folks have been naughty; they stored the string
 589          "FreeBSD" in the padding of the e_ident field of the ELF
 590          header to "brand" their ELF binaries in FreeBSD 3.x.  */
 591       if (memcmp (&elf_elfheader (abfd)->e_ident[8],
 592                   "FreeBSD", sizeof ("FreeBSD")) == 0)
 593         osabi = GDB_OSABI_FREEBSD;
 594     }
 595
 596   return osabi;
 597 }
 598 \f
 599 static void
 600 set_osabi (const char *args, int from_tty, struct cmd_list_element *c)
 601 {
 602   struct gdbarch_info info;
 603
 604   if (strcmp (set_osabi_string, "auto") == 0)
 605     user_osabi_state = osabi_auto;
 606   else if (strcmp (set_osabi_string, "default") == 0)
 607     {
 608       user_selected_osabi = GDB_OSABI_DEFAULT;
 609       user_osabi_state = osabi_user;
 610     }
 611   else
 612     {
 613       int i;
 614
 615       for (i = 1; i < GDB_OSABI_INVALID; i++)
 616         {
 617           enum gdb_osabi osabi = (enum gdb_osabi) i;
 618
 619           if (strcmp (set_osabi_string, gdbarch_osabi_name (osabi)) == 0)
 620             {
 621               user_selected_osabi = osabi;
 622               user_osabi_state = osabi_user;
 623               break;
 624             }
 625         }
 626       if (i == GDB_OSABI_INVALID)
 627         internal_error (__FILE__, __LINE__,
 628                         _("Invalid OS ABI \"%s\" passed to command handler."),
 629                         set_osabi_string);
 630     }
 631
 632   /* NOTE: At some point (true multiple architectures) we'll need to be more
 633      graceful here.  */
 634   gdbarch_info_init (&info);
 635   if (! gdbarch_update_p (info))
 636     internal_error (__FILE__, __LINE__, _("Updating OS ABI failed."));
 637 }
 638
 639 static void
 640 show_osabi (struct ui_file *file, int from_tty, struct cmd_list_element *c,
 641             const char *value)
 642 {
 643   if (user_osabi_state == osabi_auto)
 644     fprintf_filtered (file,
 645                       _("The current OS ABI is \"auto\" "
 646                         "(currently \"%s\").\n"),
 647                       gdbarch_osabi_name (gdbarch_osabi (get_current_arch ())));
 648   else
 649     fprintf_filtered (file, _("The current OS ABI is \"%s\".\n"),
 650                       gdbarch_osabi_name (user_selected_osabi));
 651
 652   if (GDB_OSABI_DEFAULT != GDB_OSABI_UNKNOWN)
 653     fprintf_filtered (file, _("The default OS ABI is \"%s\".\n"),
 654                       gdbarch_osabi_name (GDB_OSABI_DEFAULT));
 655 }
 656
 657 void _initialize_gdb_osabi ();
 658 void
 659 _initialize_gdb_osabi ()
 660 {
 661   if (strcmp (gdb_osabi_names[GDB_OSABI_INVALID].pretty, "<invalid>") != 0)
 662     internal_error
 663       (__FILE__, __LINE__,
 664        _("_initialize_gdb_osabi: gdb_osabi_names[] is inconsistent"));
 665
 666   /* Register a generic sniffer for ELF flavoured files.  */
 667   gdbarch_register_osabi_sniffer (bfd_arch_unknown,
 668                                   bfd_target_elf_flavour,
 669                                   generic_elf_osabi_sniffer);
 670
 671   /* Register the "set osabi" command.  */
 672   add_setshow_enum_cmd ("osabi", class_support, gdb_osabi_available_names,
 673                         &set_osabi_string,
 674                         _("Set OS ABI of target."),
 675                         _("Show OS ABI of target."),
 676                         NULL, set_osabi, show_osabi,
 677                         &setlist, &showlist);
 678   user_osabi_state = osabi_auto;
 679 }