aboutsummaryrefslogtreecommitdiff
path: root/gdb/osabi.c
blob: 83eb767c0b731aa49739c3b0822b471b5cde472d (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
/* OS ABI variant handling for GDB.
   Copyright 2001, 2002 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 2 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, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include "defs.h"
#include "osabi.h"

#include "elf-bfd.h"


/* This table matches the indices assigned to enum gdb_osabi.  Keep
   them in sync.  */
static const char * const gdb_osabi_names[] =
{
  "<unknown>",

  "SVR4",
  "GNU/Hurd",
  "Solaris",
  "OSF/1",
  "GNU/Linux",
  "FreeBSD a.out",
  "FreeBSD ELF",
  "NetBSD a.out",
  "NetBSD ELF",
  "Windows CE",
  "DJGPP",
  "NetWare",
  "Irix",
  "LynxOS",

  "ARM EABI v1",
  "ARM EABI v2",
  "ARM APCS",

  "<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;
  enum bfd_architecture arch;
  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, enum gdb_osabi osabi,
                        void (*init_osabi)(struct gdbarch_info,
					   struct gdbarch *))
{
  struct gdb_osabi_handler **handler_p;

  /* 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, 0));
      return;
    }

  for (handler_p = &gdb_osabi_handler_list; *handler_p != NULL;
       handler_p = &(*handler_p)->next)
    {
      if ((*handler_p)->arch == arch
	  && (*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),
	     bfd_printable_arch_mach (arch, 0));
	  /* 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 = arch;
  (*handler_p)->osabi = osabi;
  (*handler_p)->init_osabi = init_osabi;
}


/* 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;

  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;
		}
	    }
	}
    }

  return match;
}

void
gdbarch_init_osabi (struct gdbarch_info info, struct gdbarch *gdbarch,
                    enum gdb_osabi osabi)
{
  struct gdb_osabi_handler *handler;
  bfd *abfd = info.abfd;
  const struct bfd_arch_info *arch_info = gdbarch_bfd_arch_info (gdbarch);

  if (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->arch == bfd_get_arch (abfd)
	  && handler->osabi == osabi)
	{
	  (*handler->init_osabi) (info, gdbarch);
	  return;
	}
    }

  /* We assume that if GDB_MULTI_ARCH is less than GDB_MULTI_ARCH_TM
     that an ABI variant can be supported by overriding definitions in
     the tm-file.  */
  if (GDB_MULTI_ARCH > GDB_MULTI_ARCH_PARTIAL)
    fprintf_filtered
      (gdb_stderr,
       "A handler for the OS ABI \"%s\" is not built into this "
       "configuration of GDB.  "
       "Attempting to continue with the default %s settings",
       gdbarch_osabi_name (osabi),
       bfd_printable_arch_mach (arch_info->arch, arch_info->mach));
}


/* Generic sniffer for ELF flavoured files.  */

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

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

  /* .note.ABI-tag notes, used by GNU/Linux and FreeBSD.  */
  if (strcmp (name, ".note.ABI-tag") == 0 && sectsize > 0)
    {
      unsigned int name_length, data_length, note_type;
      char *note;

      /* If the section is larger than this, it's probably not what we are
	 looking for.  */
      if (sectsize > 128)
	sectsize = 128;

      note = alloca (sectsize);

      bfd_get_section_contents (abfd, sect, note,
				(file_ptr) 0, (bfd_size_type) sectsize);

      name_length = bfd_h_get_32 (abfd, note);
      data_length = bfd_h_get_32 (abfd, note + 4);
      note_type   = bfd_h_get_32 (abfd, note + 8);

      if (name_length == 4 && data_length == 16 && note_type == NT_GNU_ABI_TAG
	  && strcmp (note + 12, "GNU") == 0)
	{
	  int os_number = bfd_h_get_32 (abfd, note + 16);

	  switch (os_number)
	    {
	    case GNU_ABI_TAG_LINUX:
	      *os_ident_ptr = GDB_OSABI_LINUX;
	      break;

	    case GNU_ABI_TAG_HURD:
	      *os_ident_ptr = GDB_OSABI_HURD;
	      break;

	    case GNU_ABI_TAG_SOLARIS:
	      *os_ident_ptr = GDB_OSABI_SOLARIS;
	      break;

	    default:
	      internal_error
		(__FILE__, __LINE__,
		 "generic_elf_osabi_sniff_abi_tag_sections: unknown OS number %d",
		 os_number);
	    }
	  return;
	}
      else if (name_length == 8 && data_length == 4
	       && note_type == NT_FREEBSD_ABI_TAG
	       && strcmp (note + 12, "FreeBSD") == 0)
	{
	  /* XXX Should we check the version here?  Probably not
	     necessary yet.  */
	  *os_ident_ptr = GDB_OSABI_FREEBSD_ELF;
	}
      return;
    }

  /* .note.netbsd.ident notes, used by NetBSD.  */
  if (strcmp (name, ".note.netbsd.ident") == 0 && sectsize > 0)
    {
      unsigned int name_length, data_length, note_type;
      char *note;

      /* If the section is larger than this, it's probably not what we are
	 looking for.  */
      if (sectsize > 128) 
	sectsize = 128;

      note = alloca (sectsize);

      bfd_get_section_contents (abfd, sect, note,
				(file_ptr) 0, (bfd_size_type) sectsize);
      
      name_length = bfd_h_get_32 (abfd, note);
      data_length = bfd_h_get_32 (abfd, note + 4);
      note_type   = bfd_h_get_32 (abfd, note + 8);

      if (name_length == 7 && data_length == 4 && note_type == NT_NETBSD_IDENT
	  && strcmp (note + 12, "NetBSD") == 0)
	{
	  /* XXX Should we check the version here?  Probably not
	     necessary yet.  */
	  *os_ident_ptr = 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 elfosabi 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 notes that have been added.  */
      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;
    }

  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 (strcmp (&elf_elfheader (abfd)->e_ident[8], "FreeBSD") == 0)
	osabi = GDB_OSABI_FREEBSD_ELF;
    }

  return osabi;
}


void
_initialize_gdb_osabi (void)
{
  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);
}