1 /* Handle symbol and library versioning.
2 Copyright (C) 1997-2014 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <http://www.gnu.org/licenses/>. */
31 #define make_string(string, rest...) \
33 const char *all[] = { string, ## rest }; \
38 for (cnt = 0; cnt < sizeof (all) / sizeof (all[0]); ++cnt) \
39 len += strlen (all[cnt]); \
41 cp = result = alloca (len); \
42 for (cnt = 0; cnt < sizeof (all) / sizeof (all[0]); ++cnt) \
43 cp = __stpcpy (cp, all[cnt]); \
49 static inline struct link_map
*
50 __attribute ((always_inline
))
51 find_needed (const char *name
, struct link_map
*map
)
53 struct link_map
*tmap
;
56 for (tmap
= GL(dl_ns
)[map
->l_ns
]._ns_loaded
; tmap
!= NULL
;
58 if (_dl_name_match_p (name
, tmap
))
61 /* The required object is not in the global scope, look to see if it is
62 a dependency of the current object. */
63 for (n
= 0; n
< map
->l_searchlist
.r_nlist
; n
++)
64 if (_dl_name_match_p (name
, map
->l_searchlist
.r_list
[n
]))
65 return map
->l_searchlist
.r_list
[n
];
67 /* Should never happen. */
74 match_symbol (const char *name
, Lmid_t ns
, ElfW(Word
) hash
, const char *string
,
75 struct link_map
*map
, int verbose
, int weak
)
77 const char *strtab
= (const void *) D_PTR (map
, l_info
[DT_STRTAB
]);
78 ElfW(Addr
) def_offset
;
80 /* Initialize to make the compiler happy. */
81 const char *errstring
= NULL
;
84 /* Display information about what we are doing while debugging. */
85 if (__glibc_unlikely (GLRO(dl_debug_mask
) & DL_DEBUG_VERSIONS
))
87 checking for version `%s' in file %s [%lu] required by file %s [%lu]\n",
88 string
, DSO_FILENAME (map
->l_name
),
91 if (__glibc_unlikely (map
->l_info
[VERSYMIDX (DT_VERDEF
)] == NULL
))
93 /* The file has no symbol versioning. I.e., the dependent
94 object was linked against another version of this file. We
95 only print a message if verbose output is requested. */
98 /* XXX We cannot translate the messages. */
99 errstring
= make_string ("\
100 no version information available (required by ", name
, ")");
106 def_offset
= map
->l_info
[VERSYMIDX (DT_VERDEF
)]->d_un
.d_ptr
;
107 assert (def_offset
!= 0);
109 def
= (ElfW(Verdef
) *) ((char *) map
->l_addr
+ def_offset
);
112 /* Currently the version number of the definition entry is 1.
113 Make sure all we see is this version. */
114 if (__builtin_expect (def
->vd_version
, 1) != 1)
117 buf
[sizeof (buf
) - 1] = '\0';
118 /* XXX We cannot translate the message. */
119 errstring
= make_string ("unsupported version ",
120 _itoa (def
->vd_version
,
121 &buf
[sizeof (buf
) - 1], 10, 0),
122 " of Verdef record");
127 /* Compare the hash values. */
128 if (hash
== def
->vd_hash
)
130 ElfW(Verdaux
) *aux
= (ElfW(Verdaux
) *) ((char *) def
+ def
->vd_aux
);
132 /* To be safe, compare the string as well. */
133 if (__builtin_expect (strcmp (string
, strtab
+ aux
->vda_name
), 0)
139 /* If no more definitions we failed to find what we want. */
140 if (def
->vd_next
== 0)
143 /* Next definition. */
144 def
= (ElfW(Verdef
) *) ((char *) def
+ def
->vd_next
);
147 /* Symbol not found. If it was a weak reference it is not fatal. */
148 if (__glibc_likely (weak
))
152 /* XXX We cannot translate the message. */
153 errstring
= make_string ("weak version `", string
,
154 "' not found (required by ", name
, ")");
160 /* XXX We cannot translate the message. */
161 errstring
= make_string ("version `", string
, "' not found (required by ",
165 _dl_signal_cerror (0, DSO_FILENAME (map
->l_name
),
166 N_("version lookup error"), errstring
);
173 _dl_check_map_versions (struct link_map
*map
, int verbose
, int trace_mode
)
177 /* Pointer to section with needed versions. */
179 /* Pointer to dynamic section with definitions. */
181 /* We need to find out which is the highest version index used
183 unsigned int ndx_high
= 0;
184 /* Initialize to make the compiler happy. */
185 const char *errstring
= NULL
;
188 /* If we don't have a string table, we must be ok. */
189 if (map
->l_info
[DT_STRTAB
] == NULL
)
191 strtab
= (const void *) D_PTR (map
, l_info
[DT_STRTAB
]);
193 dyn
= map
->l_info
[VERSYMIDX (DT_VERNEED
)];
194 def
= map
->l_info
[VERSYMIDX (DT_VERDEF
)];
198 /* This file requires special versions from its dependencies. */
199 ElfW(Verneed
) *ent
= (ElfW(Verneed
) *) (map
->l_addr
+ dyn
->d_un
.d_ptr
);
201 /* Currently the version number of the needed entry is 1.
202 Make sure all we see is this version. */
203 if (__builtin_expect (ent
->vn_version
, 1) != 1)
206 buf
[sizeof (buf
) - 1] = '\0';
207 /* XXX We cannot translate the message. */
208 errstring
= make_string ("unsupported version ",
209 _itoa (ent
->vn_version
,
210 &buf
[sizeof (buf
) - 1], 10, 0),
211 " of Verneed record\n");
213 _dl_signal_error (errval
, DSO_FILENAME (map
->l_name
),
220 struct link_map
*needed
= find_needed (strtab
+ ent
->vn_file
, map
);
222 /* If NEEDED is NULL this means a dependency was not found
223 and no stub entry was created. This should never happen. */
224 assert (needed
!= NULL
);
226 /* Make sure this is no stub we created because of a missing
228 if (__builtin_expect (! trace_mode
, 1)
229 || ! __builtin_expect (needed
->l_faked
, 0))
231 /* NEEDED is the map for the file we need. Now look for the
232 dependency symbols. */
233 aux
= (ElfW(Vernaux
) *) ((char *) ent
+ ent
->vn_aux
);
236 /* Match the symbol. */
237 result
|= match_symbol (DSO_FILENAME (map
->l_name
),
238 map
->l_ns
, aux
->vna_hash
,
239 strtab
+ aux
->vna_name
,
240 needed
->l_real
, verbose
,
241 aux
->vna_flags
& VER_FLG_WEAK
);
243 /* Compare the version index. */
244 if ((unsigned int) (aux
->vna_other
& 0x7fff) > ndx_high
)
245 ndx_high
= aux
->vna_other
& 0x7fff;
247 if (aux
->vna_next
== 0)
248 /* No more symbols. */
252 aux
= (ElfW(Vernaux
) *) ((char *) aux
+ aux
->vna_next
);
256 if (ent
->vn_next
== 0)
257 /* No more dependencies. */
260 /* Next dependency. */
261 ent
= (ElfW(Verneed
) *) ((char *) ent
+ ent
->vn_next
);
265 /* We also must store the names of the defined versions. Determine
266 the maximum index here as well.
268 XXX We could avoid the loop by just taking the number of definitions
269 as an upper bound of new indeces. */
273 ent
= (ElfW(Verdef
) *) (map
->l_addr
+ def
->d_un
.d_ptr
);
276 if ((unsigned int) (ent
->vd_ndx
& 0x7fff) > ndx_high
)
277 ndx_high
= ent
->vd_ndx
& 0x7fff;
279 if (ent
->vd_next
== 0)
280 /* No more definitions. */
283 ent
= (ElfW(Verdef
) *) ((char *) ent
+ ent
->vd_next
);
289 /* Now we are ready to build the array with the version names
290 which can be indexed by the version index in the VERSYM
292 map
->l_versions
= (struct r_found_version
*)
293 calloc (ndx_high
+ 1, sizeof (*map
->l_versions
));
294 if (__glibc_unlikely (map
->l_versions
== NULL
))
296 errstring
= N_("cannot allocate version reference table");
301 /* Store the number of available symbols. */
302 map
->l_nversions
= ndx_high
+ 1;
304 /* Compute the pointer to the version symbols. */
305 map
->l_versyms
= (void *) D_PTR (map
, l_info
[VERSYMIDX (DT_VERSYM
)]);
310 ent
= (ElfW(Verneed
) *) (map
->l_addr
+ dyn
->d_un
.d_ptr
);
314 aux
= (ElfW(Vernaux
) *) ((char *) ent
+ ent
->vn_aux
);
317 ElfW(Half
) ndx
= aux
->vna_other
& 0x7fff;
318 /* In trace mode, dependencies may be missing. */
319 if (__glibc_likely (ndx
< map
->l_nversions
))
321 map
->l_versions
[ndx
].hash
= aux
->vna_hash
;
322 map
->l_versions
[ndx
].hidden
= aux
->vna_other
& 0x8000;
323 map
->l_versions
[ndx
].name
= &strtab
[aux
->vna_name
];
324 map
->l_versions
[ndx
].filename
= &strtab
[ent
->vn_file
];
327 if (aux
->vna_next
== 0)
328 /* No more symbols. */
331 /* Advance to next symbol. */
332 aux
= (ElfW(Vernaux
) *) ((char *) aux
+ aux
->vna_next
);
335 if (ent
->vn_next
== 0)
336 /* No more dependencies. */
339 /* Advance to next dependency. */
340 ent
= (ElfW(Verneed
) *) ((char *) ent
+ ent
->vn_next
);
344 /* And insert the defined versions. */
348 ent
= (ElfW(Verdef
) *) (map
->l_addr
+ def
->d_un
.d_ptr
);
352 aux
= (ElfW(Verdaux
) *) ((char *) ent
+ ent
->vd_aux
);
354 if ((ent
->vd_flags
& VER_FLG_BASE
) == 0)
356 /* The name of the base version should not be
357 available for matching a versioned symbol. */
358 ElfW(Half
) ndx
= ent
->vd_ndx
& 0x7fff;
359 map
->l_versions
[ndx
].hash
= ent
->vd_hash
;
360 map
->l_versions
[ndx
].name
= &strtab
[aux
->vda_name
];
361 map
->l_versions
[ndx
].filename
= NULL
;
364 if (ent
->vd_next
== 0)
365 /* No more definitions. */
368 ent
= (ElfW(Verdef
) *) ((char *) ent
+ ent
->vd_next
);
379 _dl_check_all_versions (struct link_map
*map
, int verbose
, int trace_mode
)
384 for (l
= map
; l
!= NULL
; l
= l
->l_next
)
385 result
|= (! l
->l_faked
386 && _dl_check_map_versions (l
, verbose
, trace_mode
));