aboutsummaryrefslogtreecommitdiff
path: root/gdb/osabi.c
blob: 04236fc2de4e56c76d1d762c338e60f39fe26938 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
/* OS ABI variant handling for GDB.

   Copyright (C) 2001, 2002, 2003, 2004, 2007, 2008
   Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"

#include "gdb_assert.h"
#include "gdb_string.h"

#include "osabi.h"
#include "arch-utils.h"
#include "gdbcmd.h"
#include "command.h"

#include "elf-bfd.h"

#ifndef GDB_OSABI_DEFAULT
#define GDB_OSABI_DEFAULT GDB_OSABI_UNKNOWN
#endif

/* State for the "set osabi" command.  */
static enum { osabi_auto, osabi_default, osabi_user } user_osabi_state;
static enum gdb_osabi user_selected_osabi;
static const char *gdb_osabi_available_names[GDB_OSABI_INVALID + 3] = {
  "auto",
  "default",
  "none",
  NULL
};
static const char *set_osabi_string;

/* This table matches the indices assigned to enum gdb_osabi.  Keep
   them in sync.  */
static const char * const gdb_osabi_names[] =
{
  "none",

  "SVR4",
  "GNU/Hurd",
  "Solaris",
  "OSF/1",
  "GNU/Linux",
  "FreeBSD a.out",
  "FreeBSD ELF",
  "NetBSD a.out",
  "NetBSD ELF",
  "OpenBSD ELF",
  "Windows CE",
  "DJGPP",
  "Irix",
  "Interix",
  "HP/UX ELF",
  "HP/UX SOM",

  "QNX Neutrino",

  "Cygwin",
  "AIX",

  "<invalid>"
};

const char *
gdbarch_osabi_name (enum gdb_osabi osabi)
{
  if (osabi >= GDB_OSABI_UNKNOWN && osabi < GDB_OSABI_INVALID)
    return gdb_osabi_names[osabi];

  return gdb_osabi_names[GDB_OSABI_INVALID];
}

/* Handler for a given architecture/OS ABI pair.  There should be only
   one handler for a given OS ABI each architecture family.  */
struct gdb_osabi_handler  
{
  struct gdb_osabi_handler *next;
  const struct bfd_arch_info *arch_info;
  enum gdb_osabi osabi;
  void (*init_osabi)(struct gdbarch_info, struct gdbarch *);
};

static struct gdb_osabi_handler *gdb_osabi_handler_list;

void
gdbarch_register_osabi (enum bfd_architecture arch, unsigned long machine,
			enum gdb_osabi osabi,
                        void (*init_osabi)(struct gdbarch_info,
					   struct gdbarch *))
{
  struct gdb_osabi_handler **handler_p;
  const struct bfd_arch_info *arch_info = bfd_lookup_arch (arch, machine);
  const char **name_ptr;

  /* Registering an OS ABI handler for "unknown" is not allowed.  */
  if (osabi == GDB_OSABI_UNKNOWN)
    {
      internal_error
	(__FILE__, __LINE__,
	 _("gdbarch_register_osabi: An attempt to register a handler for "
         "OS ABI \"%s\" for architecture %s was made.  The handler will "
	 "not be registered"),
	 gdbarch_osabi_name (osabi),
	 bfd_printable_arch_mach (arch, machine));
      return;
    }

  gdb_assert (arch_info);

  for (handler_p = &gdb_osabi_handler_list; *handler_p != NULL;
       handler_p = &(*handler_p)->next)
    {
      if ((*handler_p)->arch_info == arch_info
	  && (*handler_p)->osabi == osabi)
	{
	  internal_error
	    (__FILE__, __LINE__,
	     _("gdbarch_register_osabi: A handler for OS ABI \"%s\" "
	     "has already been registered for architecture %s"),
	     gdbarch_osabi_name (osabi),
	     arch_info->printable_name);
	  /* If user wants to continue, override previous definition.  */
	  (*handler_p)->init_osabi = init_osabi;
	  return;
	}
    }

  (*handler_p)
    = (struct gdb_osabi_handler *) xmalloc (sizeof (struct gdb_osabi_handler));
  (*handler_p)->next = NULL;
  (*handler_p)->arch_info = arch_info;
  (*handler_p)->osabi = osabi;
  (*handler_p)->init_osabi = init_osabi;

  /* Add this OS ABI to the list of enum values for "set osabi", if it isn't
     already there.  */
  for (name_ptr = gdb_osabi_available_names; *name_ptr; name_ptr ++)
    {
      if (*name_ptr == gdbarch_osabi_name (osabi))
	return;
    }
  *name_ptr++ = gdbarch_osabi_name (osabi);
  *name_ptr = NULL;
}


/* Sniffer to find the OS ABI for a given file's architecture and flavour. 
   It is legal to have multiple sniffers for each arch/flavour pair, to
   disambiguate one OS's a.out from another, for example.  The first sniffer
   to return something other than GDB_OSABI_UNKNOWN wins, so a sniffer should
   be careful to claim a file only if it knows for sure what it is.  */
struct gdb_osabi_sniffer
{
  struct gdb_osabi_sniffer *next;
  enum bfd_architecture arch;   /* bfd_arch_unknown == wildcard */
  enum bfd_flavour flavour;
  enum gdb_osabi (*sniffer)(bfd *);
};

static struct gdb_osabi_sniffer *gdb_osabi_sniffer_list;

void
gdbarch_register_osabi_sniffer (enum bfd_architecture arch,
                                enum bfd_flavour flavour,
				enum gdb_osabi (*sniffer_fn)(bfd *))
{
  struct gdb_osabi_sniffer *sniffer;

  sniffer =
    (struct gdb_osabi_sniffer *) xmalloc (sizeof (struct gdb_osabi_sniffer));
  sniffer->arch = arch;
  sniffer->flavour = flavour;
  sniffer->sniffer = sniffer_fn;

  sniffer->next = gdb_osabi_sniffer_list;
  gdb_osabi_sniffer_list = sniffer;
}


enum gdb_osabi
gdbarch_lookup_osabi (bfd *abfd)
{
  struct gdb_osabi_sniffer *sniffer;
  enum gdb_osabi osabi, match;
  int match_specific;

  /* If we aren't in "auto" mode, return the specified OS ABI.  */
  if (user_osabi_state == osabi_user)
    return user_selected_osabi;

  /* If we don't have a binary, return the default OS ABI (if set) or
     unknown (otherwise).  */
  if (abfd == NULL) 
    return GDB_OSABI_DEFAULT;

  match = GDB_OSABI_UNKNOWN;
  match_specific = 0;

  for (sniffer = gdb_osabi_sniffer_list; sniffer != NULL;
       sniffer = sniffer->next)
    {
      if ((sniffer->arch == bfd_arch_unknown /* wildcard */
	   || sniffer->arch == bfd_get_arch (abfd))
	  && sniffer->flavour == bfd_get_flavour (abfd))
	{
	  osabi = (*sniffer->sniffer) (abfd);
	  if (osabi < GDB_OSABI_UNKNOWN || osabi >= GDB_OSABI_INVALID)
	    {
	      internal_error
		(__FILE__, __LINE__,
		 _("gdbarch_lookup_osabi: invalid OS ABI (%d) from sniffer "
		 "for architecture %s flavour %d"),
		 (int) osabi,
		 bfd_printable_arch_mach (bfd_get_arch (abfd), 0),
		 (int) bfd_get_flavour (abfd));
	    }
	  else if (osabi != GDB_OSABI_UNKNOWN)
	    {
	      /* A specific sniffer always overrides a generic sniffer.
		 Croak on multiple match if the two matches are of the
		 same class.  If the user wishes to continue, we'll use
		 the first match.  */
	      if (match != GDB_OSABI_UNKNOWN)
		{
		  if ((match_specific && sniffer->arch != bfd_arch_unknown)
		   || (!match_specific && sniffer->arch == bfd_arch_unknown))
		    {
		      internal_error
		        (__FILE__, __LINE__,
		         _("gdbarch_lookup_osabi: multiple %sspecific OS ABI "
			 "match for architecture %s flavour %d: first "
			 "match \"%s\", second match \"%s\""),
			 match_specific ? "" : "non-",
		         bfd_printable_arch_mach (bfd_get_arch (abfd), 0),
		         (int) bfd_get_flavour (abfd),
		         gdbarch_osabi_name (match),
		         gdbarch_osabi_name (osabi));
		    }
		  else if (sniffer->arch != bfd_arch_unknown)
		    {
		      match = osabi;
		      match_specific = 1;
		    }
		}
	      else
		{
		  match = osabi;
		  if (sniffer->arch != bfd_arch_unknown)
		    match_specific = 1;
		}
	    }
	}
    }

  /* If we didn't find a match, but a default was specified at configure
     time, return the default.  */
  if (GDB_OSABI_DEFAULT != GDB_OSABI_UNKNOWN && match == GDB_OSABI_UNKNOWN)
    return GDB_OSABI_DEFAULT;
  else
    return match;
}


/* Return non-zero if architecture A can run code written for
   architecture B.  */
static int
can_run_code_for (const struct bfd_arch_info *a, const struct bfd_arch_info *b)
{
  /* BFD's 'A->compatible (A, B)' functions return zero if A and B are
     incompatible.  But if they are compatible, it returns the 'more
     featureful' of the two arches.  That is, if A can run code
     written for B, but B can't run code written for A, then it'll
     return A.

     struct bfd_arch_info objects are singletons: that is, there's
     supposed to be exactly one instance for a given machine.  So you
     can tell whether two are equivalent by comparing pointers.  */
  return (a == b || a->compatible (a, b) == a);
}


void
gdbarch_init_osabi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
  struct gdb_osabi_handler *handler;

  if (info.osabi == GDB_OSABI_UNKNOWN)
    {
      /* Don't complain about an unknown OSABI.  Assume the user knows
         what they are doing.  */
      return;
    }

  for (handler = gdb_osabi_handler_list; handler != NULL;
       handler = handler->next)
    {
      if (handler->osabi != info.osabi)
	continue;

      /* If the architecture described by ARCH_INFO can run code for
         the architcture we registered the handler for, then the
         handler is applicable.  Note, though, that if the handler is
         for an architecture that is a superset of ARCH_INFO, we can't
         use that --- it would be perfectly correct for it to install
         gdbarch methods that refer to registers / instructions /
         other facilities ARCH_INFO doesn't have.

         NOTE: kettenis/20021027: There may be more than one machine
	 type that is compatible with the desired machine type.  Right
	 now we simply return the first match, which is fine for now.
	 However, we might want to do something smarter in the future.  */
      /* NOTE: cagney/2003-10-23: The code for "a can_run_code_for b"
         is implemented using BFD's compatible method (a->compatible
         (b) == a -- the lowest common denominator between a and b is
         a).  That method's definition of compatible may not be as you
         expect.  For instance the test "amd64 can run code for i386"
         (or more generally "64-bit ISA can run code for the 32-bit
         ISA").  BFD doesn't normally consider 32-bit and 64-bit
         "compatible" so it doesn't succeed.  */
      if (can_run_code_for (info.bfd_arch_info, handler->arch_info))
	{
	  (*handler->init_osabi) (info, gdbarch);
	  return;
	}
    }

  warning
    ("A handler for the OS ABI \"%s\" is not built into this configuration\n"
     "of GDB.  Attempting to continue with the default %s settings.\n",
     gdbarch_osabi_name (info.osabi),
     info.bfd_arch_info->printable_name);
}

/* Limit on the amount of data to be read.  */
#define MAX_NOTESZ	128

/* Return non-zero if NOTE matches NAME, DESCSZ and TYPE.  */

static int
check_note (bfd *abfd, asection *sect, const char *note,
	    const char *name, unsigned long descsz, unsigned long type)
{
  unsigned long notesz;

  /* Calculate the size of this note.  */
  notesz = strlen (name) + 1;
  notesz = ((notesz + 3) & ~3);
  notesz += descsz;
  notesz = ((notesz + 3) & ~3);

  /* If this assertion triggers, increase MAX_NOTESZ.  */
  gdb_assert (notesz <= MAX_NOTESZ);

  /* Check whether SECT is big enough to comtain the complete note.  */
  if (notesz > bfd_section_size (abfd, sect))
    return 0;

  /* Check the note name.  */
  if (bfd_h_get_32 (abfd, note) != (strlen (name) + 1)
      || strcmp (note + 12, name) != 0)
    return 0;

  /* Check the descriptor size.  */
  if (bfd_h_get_32 (abfd, note + 4) != descsz)
    return 0;

  /* Check the note type.  */
  if (bfd_h_get_32 (abfd, note + 8) != type)
    return 0;

  return 1;
}

/* Generic sniffer for ELF flavoured files.  */

void
generic_elf_osabi_sniff_abi_tag_sections (bfd *abfd, asection *sect, void *obj)
{
  enum gdb_osabi *osabi = obj;
  const char *name;
  unsigned int sectsize;
  char *note;

  name = bfd_get_section_name (abfd, sect);
  sectsize = bfd_section_size (abfd, sect);

  /* Limit the amount of data to read.  */
  if (sectsize > MAX_NOTESZ)
    sectsize = MAX_NOTESZ;

  note = alloca (sectsize);
  bfd_get_section_contents (abfd, sect, note, 0, sectsize);

  /* .note.ABI-tag notes, used by GNU/Linux and FreeBSD.  */
  if (strcmp (name, ".note.ABI-tag") == 0)
    {
      /* GNU.  */
      if (check_note (abfd, sect, note, "GNU", 16, NT_GNU_ABI_TAG))
	{
	  unsigned int abi_tag = bfd_h_get_32 (abfd, note + 16);

	  switch (abi_tag)
	    {
	    case GNU_ABI_TAG_LINUX:
	      *osabi = GDB_OSABI_LINUX;
	      break;

	    case GNU_ABI_TAG_HURD:
	      *osabi = GDB_OSABI_HURD;
	      break;

	    case GNU_ABI_TAG_SOLARIS:
	      *osabi = GDB_OSABI_SOLARIS;
	      break;

	    case GNU_ABI_TAG_FREEBSD:
	      *osabi = GDB_OSABI_FREEBSD_ELF;
	      break;

	    case GNU_ABI_TAG_NETBSD:
	      *osabi = GDB_OSABI_NETBSD_ELF;
	      break;

	    default:
	      internal_error (__FILE__, __LINE__, _("\
generic_elf_osabi_sniff_abi_tag_sections: unknown OS number %d"),
			      abi_tag);
	    }
	  return;
	}

      /* FreeBSD.  */
      if (check_note (abfd, sect, note, "FreeBSD", 4, NT_FREEBSD_ABI_TAG))
	{
	  /* There is no need to check the version yet.  */
	  *osabi = GDB_OSABI_FREEBSD_ELF;
	  return;
	}

      return;
    }
      
  /* .note.netbsd.ident notes, used by NetBSD.  */
  if (strcmp (name, ".note.netbsd.ident") == 0
      && check_note (abfd, sect, note, "NetBSD", 4, NT_NETBSD_IDENT))
    {
      /* There is no need to check the version yet.  */
      *osabi = GDB_OSABI_NETBSD_ELF;
      return;
    }

  /* .note.openbsd.ident notes, used by OpenBSD.  */
  if (strcmp (name, ".note.openbsd.ident") == 0
      && check_note (abfd, sect, note, "OpenBSD", 4, NT_OPENBSD_IDENT))
    {
      /* There is no need to check the version yet.  */
      *osabi = GDB_OSABI_OPENBSD_ELF;
      return;
    }

  /* .note.netbsdcore.procinfo notes, used by NetBSD.  */
  if (strcmp (name, ".note.netbsdcore.procinfo") == 0)
    {
      *osabi = GDB_OSABI_NETBSD_ELF;
      return;
    }
}

static enum gdb_osabi
generic_elf_osabi_sniffer (bfd *abfd)
{
  unsigned int elfosabi;
  enum gdb_osabi osabi = GDB_OSABI_UNKNOWN;

  elfosabi = elf_elfheader (abfd)->e_ident[EI_OSABI];

  switch (elfosabi)
    {
    case ELFOSABI_NONE:
      /* When the EI_OSABI field in the ELF header is ELFOSABI_NONE
         (0), then the ELF structures in the file are conforming to
         the base specification for that machine (there are no
         OS-specific extensions).  In order to determine the real OS
         in use we must look for OS-specific notes.  */
      bfd_map_over_sections (abfd,
			     generic_elf_osabi_sniff_abi_tag_sections,
			     &osabi);
      break;

    case ELFOSABI_FREEBSD:
      osabi = GDB_OSABI_FREEBSD_ELF;
      break;

    case ELFOSABI_NETBSD:
      osabi = GDB_OSABI_NETBSD_ELF;
      break;

    case ELFOSABI_LINUX:
      osabi = GDB_OSABI_LINUX;
      break;

    case ELFOSABI_HURD:
      osabi = GDB_OSABI_HURD;
      break;

    case ELFOSABI_SOLARIS:
      osabi = GDB_OSABI_SOLARIS;
      break;

    case ELFOSABI_HPUX:
      /* For some reason the default value for the EI_OSABI field is
         ELFOSABI_HPUX for all PA-RISC targets (with the exception of
         GNU/Linux).  We use HP-UX ELF as the default, but let any
         OS-specific notes override this.  */
      osabi = GDB_OSABI_HPUX_ELF;
      bfd_map_over_sections (abfd,
			     generic_elf_osabi_sniff_abi_tag_sections,
			     &osabi);
      break;
    }

  if (osabi == GDB_OSABI_UNKNOWN)
    {
      /* The FreeBSD folks have been naughty; they stored the string
         "FreeBSD" in the padding of the e_ident field of the ELF
         header to "brand" their ELF binaries in FreeBSD 3.x.  */
      if (memcmp (&elf_elfheader (abfd)->e_ident[8],
		  "FreeBSD", sizeof ("FreeBSD")) == 0)
	osabi = GDB_OSABI_FREEBSD_ELF;
    }

  return osabi;
}

static void
set_osabi (char *args, int from_tty, struct cmd_list_element *c)
{
  struct gdbarch_info info;

  if (strcmp (set_osabi_string, "auto") == 0)
    user_osabi_state = osabi_auto;
  else if (strcmp (set_osabi_string, "default") == 0)
    {
      user_selected_osabi = GDB_OSABI_DEFAULT;
      user_osabi_state = osabi_user;
    }
  else if (strcmp (set_osabi_string, "none") == 0)
    {
      user_selected_osabi = GDB_OSABI_UNKNOWN;
      user_osabi_state = osabi_user;
    }
  else
    {
      int i;
      for (i = 1; i < GDB_OSABI_INVALID; i++)
	if (strcmp (set_osabi_string, gdbarch_osabi_name (i)) == 0)
	  {
	    user_selected_osabi = i;
	    user_osabi_state = osabi_user;
	    break;
	  }
      if (i == GDB_OSABI_INVALID)
	internal_error (__FILE__, __LINE__,
			_("Invalid OS ABI \"%s\" passed to command handler."),
			set_osabi_string);
    }

  /* NOTE: At some point (true multiple architectures) we'll need to be more
     graceful here.  */
  gdbarch_info_init (&info);
  if (! gdbarch_update_p (info))
    internal_error (__FILE__, __LINE__, _("Updating OS ABI failed."));
}

static void
show_osabi (struct ui_file *file, int from_tty, struct cmd_list_element *c,
	    const char *value)
{
  if (user_osabi_state == osabi_auto)
    fprintf_filtered (file,
		      _("The current OS ABI is \"auto\" (currently \"%s\").\n"),
		      gdbarch_osabi_name (gdbarch_osabi (current_gdbarch)));
  else
    fprintf_filtered (file, _("The current OS ABI is \"%s\".\n"),
		      gdbarch_osabi_name (user_selected_osabi));

  if (GDB_OSABI_DEFAULT != GDB_OSABI_UNKNOWN)
    fprintf_filtered (file, _("The default OS ABI is \"%s\".\n"),
		      gdbarch_osabi_name (GDB_OSABI_DEFAULT));
}

extern initialize_file_ftype _initialize_gdb_osabi; /* -Wmissing-prototype */

void
_initialize_gdb_osabi (void)
{
  struct cmd_list_element *c;

  if (strcmp (gdb_osabi_names[GDB_OSABI_INVALID], "<invalid>") != 0)
    internal_error
      (__FILE__, __LINE__,
       _("_initialize_gdb_osabi: gdb_osabi_names[] is inconsistent"));

  /* Register a generic sniffer for ELF flavoured files.  */
  gdbarch_register_osabi_sniffer (bfd_arch_unknown,
				  bfd_target_elf_flavour,
				  generic_elf_osabi_sniffer);

  /* Register the "set osabi" command.  */
  add_setshow_enum_cmd ("osabi", class_support, gdb_osabi_available_names,
			&set_osabi_string, _("\
Set OS ABI of target."), _("\
Show OS ABI of target."), NULL,
			set_osabi,
			show_osabi,
			&setlist, &showlist);
  user_osabi_state = osabi_auto;
}