aboutsummaryrefslogtreecommitdiff
path: root/elf/dl-version.c
blob: 6715bc1547629db30ba5378aff29d27fcd147096 (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
/* Handle symbol and library versioning.
   Copyright (C) 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <elf.h>
#include <errno.h>
#include <libintl.h>
#include <stdlib.h>
#include <string.h>
#include <ldsodefs.h>
#include <stdio-common/_itoa.h>

#include <assert.h>


#ifndef VERSYMIDX
# define VERSYMIDX(tag)	(DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (tag))
#endif


#define make_string(string, rest...) \
  ({									      \
    const char *all[] = { string, ## rest };				      \
    size_t len, cnt;							      \
    char *result, *cp;							      \
									      \
    len = 1;								      \
    for (cnt = 0; cnt < sizeof (all) / sizeof (all[0]); ++cnt)		      \
      len += strlen (all[cnt]);						      \
									      \
    cp = result = alloca (len);						      \
    for (cnt = 0; cnt < sizeof (all) / sizeof (all[0]); ++cnt)		      \
      cp = __stpcpy (cp, all[cnt]);					      \
									      \
    result;								      \
  })


static inline struct link_map *
find_needed (const char *name, struct link_map *map)
{
  struct link_map *tmap;
  unsigned int n;

  for (tmap = _dl_loaded; tmap != NULL; tmap = tmap->l_next)
    if (_dl_name_match_p (name, tmap))
      return tmap;

  /* The required object is not in the global scope, look to see if it is
     a dependency of the current object.  */
  for (n = 0; n < map->l_searchlist.r_nlist; n++)
    if (_dl_name_match_p (name, map->l_searchlist.r_list[n]))
      return map->l_searchlist.r_list[n];

  /* Should never happen.  */
  return NULL;
}


static int
internal_function
match_symbol (const char *name, ElfW(Word) hash, const char *string,
	      struct link_map *map, int verbose, int weak)
{
  const char *strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
  ElfW(Addr) def_offset;
  ElfW(Verdef) *def;
  /* Initialize to make the compiler happy.  */
  const char *errstring = NULL;
  int result = 0;

  /* Display information about what we are doing while debugging.  */
  if (__builtin_expect (_dl_debug_mask & DL_DEBUG_VERSIONS, 0))
    _dl_debug_printf ("\
checking for version `%s' in file %s required by file %s\n",
		      string, map->l_name[0] ? map->l_name : _dl_argv[0],
		      name);

  if (__builtin_expect (map->l_info[VERSYMIDX (DT_VERDEF)] == NULL, 0))
    {
      /* The file has no symbol versioning.  I.e., the dependent
	 object was linked against another version of this file.  We
	 only print a message if verbose output is requested.  */
      if (verbose)
	{
	  /* XXX We cannot translate the messages.  */
	  errstring = make_string ("\
no version information available (required by ", name, ")");
	  goto call_cerror;
	}
      return 0;
    }

  def_offset = map->l_info[VERSYMIDX (DT_VERDEF)]->d_un.d_ptr;
  assert (def_offset != 0);

  def = (ElfW(Verdef) *) ((char *) map->l_addr + def_offset);
  while (1)
    {
      /* Currently the version number of the definition entry is 1.
	 Make sure all we see is this version.  */
      if (__builtin_expect (def->vd_version, 1) != 1)
	{
	  char buf[20];
	  buf[sizeof (buf) - 1] = '\0';
	  /* XXX We cannot translate the message.  */
	  errstring = make_string ("unsupported version ",
				   _itoa_word (def->vd_version,
					       &buf[sizeof (buf) - 1], 10, 0),
				   " of Verdef record");
	  result = 1;
	  goto call_cerror;
	}

      /* Compare the hash values.  */
      if (hash == def->vd_hash)
	{
	  ElfW(Verdaux) *aux = (ElfW(Verdaux) *) ((char *) def + def->vd_aux);

	  /* To be safe, compare the string as well.  */
	  if (__builtin_expect (strcmp (string, strtab + aux->vda_name), 0)
	      == 0)
	    /* Bingo!  */
	    return 0;
	}

      /* If no more definitions we failed to find what we want.  */
      if (def->vd_next == 0)
	break;

      /* Next definition.  */
      def = (ElfW(Verdef) *) ((char *) def + def->vd_next);
    }

  /* Symbol not found.  If it was a weak reference it is not fatal.  */
  if (__builtin_expect (weak, 1))
    {
      if (verbose)
	{
	  /* XXX We cannot translate the message.  */
	  errstring = make_string ("weak version `", string,
				   "' not found (required by ", name, ")");
	  goto call_cerror;
	}
      return 0;
    }

  /* XXX We cannot translate the message.  */
  errstring = make_string ("version `", string, "' not found (required by ",
			   name, ")");
  result = 1;
 call_cerror:
  _dl_signal_cerror (0, map->l_name[0] ? map->l_name : _dl_argv[0], NULL,
		     errstring);
  return result;
}


int
internal_function
_dl_check_map_versions (struct link_map *map, int verbose, int trace_mode)
{
  int result = 0;
  const char *strtab;
  /* Pointer to section with needed versions.  */
  ElfW(Dyn) *dyn;
  /* Pointer to dynamic section with definitions.  */
  ElfW(Dyn) *def;
  /* We need to find out which is the highest version index used
    in a dependecy.  */
  unsigned int ndx_high = 0;
  /* Initialize to make the compiler happy.  */
  const char *errstring = NULL;
  int errval = 0;

  /* If we don't have a string table, we must be ok.  */
  if (map->l_info[DT_STRTAB] == NULL)
    return 0;
  strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);

  dyn = map->l_info[VERSYMIDX (DT_VERNEED)];
  def = map->l_info[VERSYMIDX (DT_VERDEF)];

  if (dyn != NULL)
    {
      /* This file requires special versions from its dependencies.  */
      ElfW(Verneed) *ent = (ElfW(Verneed) *) (map->l_addr + dyn->d_un.d_ptr);

      /* Currently the version number of the needed entry is 1.
	 Make sure all we see is this version.  */
      if (__builtin_expect (ent->vn_version, 1) != 1)
	{
	  char buf[20];
	  buf[sizeof (buf) - 1] = '\0';
	  /* XXX We cannot translate the message.  */
	  errstring = make_string ("unsupported version ",
				   _itoa_word (ent->vn_version,
					       &buf[sizeof (buf) - 1], 10, 0),
				   " of Verneed record\n");
	call_error:
	  _dl_signal_error (errval, (*map->l_name ? map->l_name : _dl_argv[0]),
			    NULL, errstring);
	}

      while (1)
	{
	  ElfW(Vernaux) *aux;
	  struct link_map *needed = find_needed (strtab + ent->vn_file, map);

	  /* If NEEDED is NULL this means a dependency was not found
	     and no stub entry was created.  This should never happen.  */
	  assert (needed != NULL);

	  /* Make sure this is no stub we created because of a missing
	     dependency.  */
	  if (__builtin_expect (! trace_mode, 1)
	      || ! __builtin_expect (needed->l_faked, 0))
	    {
	      /* NEEDED is the map for the file we need.  Now look for the
		 dependency symbols.  */
	      aux = (ElfW(Vernaux) *) ((char *) ent + ent->vn_aux);
	      while (1)
		{
		  /* Match the symbol.  */
		  result |= match_symbol ((*map->l_name
					   ? map->l_name : _dl_argv[0]),
					  aux->vna_hash,
					  strtab + aux->vna_name,
					  needed, verbose,
					  aux->vna_flags & VER_FLG_WEAK);

		  /* Compare the version index.  */
		  if ((unsigned int) (aux->vna_other & 0x7fff) > ndx_high)
		    ndx_high = aux->vna_other & 0x7fff;

		  if (aux->vna_next == 0)
		    /* No more symbols.  */
		    break;

		  /* Next symbol.  */
		  aux = (ElfW(Vernaux) *) ((char *) aux + aux->vna_next);
		}
	    }

	  if (ent->vn_next == 0)
	    /* No more dependencies.  */
	    break;

	  /* Next dependency.  */
	  ent = (ElfW(Verneed) *) ((char *) ent + ent->vn_next);
	}
    }

  /* We also must store the names of the defined versions.  Determine
     the maximum index here as well.

     XXX We could avoid the loop by just taking the number of definitions
     as an upper bound of new indeces.  */
  if (def != NULL)
    {
      ElfW(Verdef) *ent;
      ent = (ElfW(Verdef) *) (map->l_addr + def->d_un.d_ptr);
      while (1)
	{
	  if ((unsigned int) (ent->vd_ndx & 0x7fff) > ndx_high)
	    ndx_high = ent->vd_ndx & 0x7fff;

	  if (ent->vd_next == 0)
	    /* No more definitions.  */
	    break;

	  ent = (ElfW(Verdef) *) ((char *) ent + ent->vd_next);
	}
    }

  if (ndx_high > 0)
    {
      /* Now we are ready to build the array with the version names
	 which can be indexed by the version index in the VERSYM
	 section.  */
      map->l_versions = (struct r_found_version *)
	calloc (ndx_high + 1, sizeof (*map->l_versions));
      if (__builtin_expect (map->l_versions == NULL, 0))
	{
	  errstring = N_("cannot allocate version reference table");
	  errval = ENOMEM;
	  goto call_error;
	}

      /* Store the number of available symbols.  */
      map->l_nversions = ndx_high + 1;

      /* Compute the pointer to the version symbols.  */
      map->l_versyms = (void *) D_PTR (map, l_info[VERSYMIDX (DT_VERSYM)]);

      if (dyn != NULL)
	{
	  ElfW(Verneed) *ent;
	  ent = (ElfW(Verneed) *) (map->l_addr + dyn->d_un.d_ptr);
	  while (1)
	    {
	      ElfW(Vernaux) *aux;
	      aux = (ElfW(Vernaux) *) ((char *) ent + ent->vn_aux);
	      while (1)
		{
		  ElfW(Half) ndx = aux->vna_other & 0x7fff;
		  map->l_versions[ndx].hash = aux->vna_hash;
		  map->l_versions[ndx].hidden = aux->vna_other & 0x8000;
		  map->l_versions[ndx].name = &strtab[aux->vna_name];
		  map->l_versions[ndx].filename = &strtab[ent->vn_file];

		  if (aux->vna_next == 0)
		    /* No more symbols.  */
		    break;

		  /* Advance to next symbol.  */
		  aux = (ElfW(Vernaux) *) ((char *) aux + aux->vna_next);
		}

	      if (ent->vn_next == 0)
		/* No more dependencies.  */
		break;

	      /* Advance to next dependency.  */
	      ent = (ElfW(Verneed) *) ((char *) ent + ent->vn_next);
	    }
	}

      /* And insert the defined versions.  */
      if (def != NULL)
	{
	  ElfW(Verdef) *ent;
	  ent = (ElfW(Verdef)  *) (map->l_addr + def->d_un.d_ptr);
	  while (1)
	    {
	      ElfW(Verdaux) *aux;
	      aux = (ElfW(Verdaux) *) ((char *) ent + ent->vd_aux);

	      if ((ent->vd_flags & VER_FLG_BASE) == 0)
		{
		  /* The name of the base version should not be
		     available for matching a versioned symbol.  */
		  ElfW(Half) ndx = ent->vd_ndx & 0x7fff;
		  map->l_versions[ndx].hash = ent->vd_hash;
		  map->l_versions[ndx].name = &strtab[aux->vda_name];
		  map->l_versions[ndx].filename = NULL;
		}

	      if (ent->vd_next == 0)
		/* No more definitions.  */
		break;

	      ent = (ElfW(Verdef) *) ((char *) ent + ent->vd_next);
	    }
	}
    }

  return result;
}


int
internal_function
_dl_check_all_versions (struct link_map *map, int verbose, int trace_mode)
{
  struct link_map *l;
  int result = 0;

  for (l = map; l != NULL; l = l->l_next)
    result |= ! l->l_faked && _dl_check_map_versions (l, verbose, trace_mode);

  return result;
}