1 /* Load the dependencies of a mapped object.
2 Copyright (C) 1996,1997,1998,1999,2000,2001 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public License as
7 published by the Free Software Foundation; either version 2 of the
8 License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Library General Public License for more details.
15 You should have received a copy of the GNU Library General Public
16 License along with the GNU C Library; see the file COPYING.LIB. If not,
17 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA. */
27 #include <sys/param.h>
32 /* Whether an shared object references one or more auxiliary objects
33 is signaled by the AUXTAG entry in l_info. */
34 #define AUXTAG (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM \
35 + DT_EXTRATAGIDX (DT_AUXILIARY))
36 /* Whether an shared object references one or more auxiliary objects
37 is signaled by the AUXTAG entry in l_info. */
38 #define FILTERTAG (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM \
39 + DT_EXTRATAGIDX (DT_FILTER))
41 /* This is zero at program start to signal that the global scope map is
42 allocated by rtld. Later it keeps the size of the map. It might be
43 reset if in _dl_close if the last global object is removed. */
44 size_t _dl_global_scope_alloc;
46 extern size_t _dl_platformlen;
48 /* When loading auxiliary objects we must ignore errors. It's ok if
49 an object is missing. */
52 /* The arguments to openaux. */
58 /* The return value of openaux. */
65 struct openaux_args *args = (struct openaux_args *) a;
67 args->aux = _dl_map_object (args->map, args->name, 0,
68 (args->map->l_type == lt_executable
69 ? lt_library : args->map->l_type),
75 /* We use a very special kind of list to track the path
76 through the list of loaded shared objects. We have to
77 produce a flat list with unique members of all involved objects.
81 int done; /* Nonzero if this map was processed. */
82 struct link_map *map; /* The data. */
83 struct list *next; /* Elements for normal list. */
87 /* Macro to expand DST. It is an macro since we use `alloca'. */
88 #define expand_dst(l, str, fatal) \
90 const char *__str = (str); \
91 const char *__result = __str; \
92 size_t __cnt = DL_DST_COUNT(__str, 0); \
98 /* DST must not appear in SUID/SGID programs. */ \
99 if (__libc_enable_secure) \
100 _dl_signal_error (0, __str, \
101 N_("DST not allowed in SUID/SGID programs")); \
103 __newp = (char *) alloca (DL_DST_REQUIRED (l, __str, strlen (__str), \
106 __result = DL_DST_SUBSTITUTE (l, __str, __newp, 0); \
108 if (*__result == '\0') \
110 /* The replacement for the DST is not known. We can't \
113 _dl_signal_error (0, __str, N_("\
114 empty dynamics string token substitution")); \
117 /* This is for DT_AUXILIARY. */ \
118 if (__builtin_expect (_dl_debug_mask & DL_DEBUG_LIBS, 0)) \
119 _dl_debug_printf ("cannot load auxiliary `%s' because of" \
120 "empty dynamic string token " \
121 "substitution\n", __str); \
132 _dl_map_object_deps (struct link_map *map,
133 struct link_map **preloads, unsigned int npreloads,
136 struct list known[1 + npreloads + 1];
137 struct list *runp, *tail;
138 unsigned int nlist, i;
143 const char *errstring;
146 auto inline void preload (struct link_map *map);
148 inline void preload (struct link_map *map)
150 known[nlist].done = 0;
151 known[nlist].map = map;
152 known[nlist].next = &known[nlist + 1];
155 /* We use `l_reserved' as a mark bit to detect objects we have
156 already put in the search list and avoid adding duplicate
157 elements later in the list. */
161 /* No loaded object so far. */
164 /* First load MAP itself. */
167 /* Add the preloaded items after MAP but before any of its dependencies. */
168 for (i = 0; i < npreloads; ++i)
169 preload (preloads[i]);
171 /* Terminate the lists. */
172 known[nlist - 1].next = NULL;
174 /* Pointer to last unique object. */
175 tail = &known[nlist - 1];
177 /* Process each element of the search list, loading each of its
178 auxiliary objects and immediate dependencies. Auxiliary objects
179 will be added in the list before the object itself and
180 dependencies will be appended to the list as we step through it.
181 This produces a flat, ordered list that represents a
182 breadth-first search of the dependency tree.
184 The whole process is complicated by the fact that we better
185 should use alloca for the temporary list elements. But using
186 alloca means we cannot use recursive function calls. */
192 for (runp = known; runp; )
194 struct link_map *l = runp->map;
195 struct link_map **needed = NULL;
196 unsigned int nneeded = 0;
198 /* Unless otherwise stated, this object is handled. */
201 /* Allocate a temporary record to contain the references to the
202 dependencies of this object. */
203 if (l->l_searchlist.r_list == NULL && l->l_initfini == NULL
204 && l != map && l->l_ldnum > 0)
205 needed = (struct link_map **) alloca (l->l_ldnum
206 * sizeof (struct link_map *));
208 if (l->l_info[DT_NEEDED] || l->l_info[AUXTAG] || l->l_info[FILTERTAG])
210 const char *strtab = (const void *) D_PTR (l, l_info[DT_STRTAB]);
211 struct openaux_args args;
215 args.strtab = strtab;
217 args.trace_mode = trace_mode;
220 for (d = l->l_ld; d->d_tag != DT_NULL; ++d)
221 if (__builtin_expect (d->d_tag, DT_NEEDED) == DT_NEEDED)
223 /* Map in the needed object. */
224 struct link_map *dep;
226 /* Recognize DSTs. */
227 name = expand_dst (l, strtab + d->d_un.d_val, 0);
228 /* Store the tag in the argument structure. */
231 if (_dl_catch_error (&objname, &errstring, openaux, &args))
234 errno_reason = errno;
242 if (! dep->l_reserved)
244 /* Allocate new entry. */
247 newp = alloca (sizeof (struct list));
249 /* Append DEP to the list. */
256 /* Set the mark bit that says it's already in the list. */
260 /* Remember this dependency. */
262 needed[nneeded++] = dep;
264 else if (d->d_tag == DT_AUXILIARY || d->d_tag == DT_FILTER)
268 /* Recognize DSTs. */
269 name = expand_dst (l, strtab + d->d_un.d_val,
270 d->d_tag == DT_AUXILIARY);
271 /* Store the tag in the argument structure. */
274 if (d->d_tag == DT_AUXILIARY)
276 /* Say that we are about to load an auxiliary library. */
277 if (__builtin_expect (_dl_debug_mask & DL_DEBUG_LIBS, 0))
278 _dl_debug_printf ("load auxiliary object=%s"
279 " requested by file=%s\n", name,
281 ? l->l_name : _dl_argv[0]);
283 /* We must be prepared that the addressed shared
284 object is not available. */
285 if (_dl_catch_error (&objname, &errstring, openaux, &args))
287 /* We are not interested in the error message. */
288 assert (errstring != NULL);
289 if (errstring != _dl_out_of_memory)
290 free ((char *) errstring);
292 /* Simply ignore this error and continue the work. */
298 /* Say that we are about to load an auxiliary library. */
299 if (__builtin_expect (_dl_debug_mask & DL_DEBUG_LIBS, 0))
300 _dl_debug_printf ("load filtered object=%s"
301 " requested by file=%s\n", name,
303 ? l->l_name : _dl_argv[0]);
305 /* For filter objects the dependency must be available. */
306 if (_dl_catch_error (&objname, &errstring, openaux, &args))
309 errno_reason = errno;
316 /* The auxiliary object is actually available.
317 Incorporate the map in all the lists. */
319 /* Allocate new entry. This always has to be done. */
320 newp = alloca (sizeof (struct list));
322 /* We want to insert the new map before the current one,
323 but we have no back links. So we copy the contents of
324 the current entry over. Note that ORIG and NEWP now
325 have switched their meanings. */
326 memcpy (newp, orig, sizeof (*newp));
328 /* Initialize new entry. */
330 orig->map = args.aux;
332 /* Remember this dependency. */
334 needed[nneeded++] = args.aux;
336 /* We must handle two situations here: the map is new,
337 so we must add it in all three lists. If the map
338 is already known, we have two further possibilities:
339 - if the object is before the current map in the
340 search list, we do nothing. It is already found
342 - if the object is after the current one, we must
343 move it just before the current map to make sure
344 the symbols are found early enough
346 if (args.aux->l_reserved)
348 /* The object is already somewhere in the list.
352 /* This object is already in the search list we
353 are building. Don't add a duplicate pointer.
354 Just added by _dl_map_object. */
355 for (late = newp; late->next; late = late->next)
356 if (late->next->map == args.aux)
361 /* The object is somewhere behind the current
362 position in the search path. We have to
363 move it to this earlier position. */
366 /* Now remove the later entry from the list
367 and adjust the tail pointer. */
368 if (tail == late->next)
370 late->next = late->next->next;
372 /* We must move the object earlier in the chain. */
373 if (args.aux->l_prev)
374 args.aux->l_prev->l_next = args.aux->l_next;
375 if (args.aux->l_next)
376 args.aux->l_next->l_prev = args.aux->l_prev;
378 args.aux->l_prev = newp->map->l_prev;
379 newp->map->l_prev = args.aux;
380 if (args.aux->l_prev != NULL)
381 args.aux->l_prev->l_next = args.aux;
382 args.aux->l_next = newp->map;
386 /* The object must be somewhere earlier in the
387 list. That's good, we only have to insert
388 an entry for the duplicate list. */
389 orig->next = NULL; /* Never used. */
391 /* Now we have a problem. The element
392 pointing to ORIG in the list must
393 point to NEWP now. This is the only place
394 where we need this backreference and this
395 situation is really not that frequent. So
396 we don't use a double-linked list but
397 instead search for the preceding element. */
399 while (late->next != orig)
406 /* This is easy. We just add the symbol right here. */
409 /* Set the mark bit that says it's already in the list. */
410 args.aux->l_reserved = 1;
412 /* The only problem is that in the double linked
413 list of all objects we don't have this new
414 object at the correct place. Correct this here. */
415 if (args.aux->l_prev)
416 args.aux->l_prev->l_next = args.aux->l_next;
417 if (args.aux->l_next)
418 args.aux->l_next->l_prev = args.aux->l_prev;
420 args.aux->l_prev = newp->map->l_prev;
421 newp->map->l_prev = args.aux;
422 if (args.aux->l_prev != NULL)
423 args.aux->l_prev->l_next = args.aux;
424 args.aux->l_next = newp->map;
427 /* Move the tail pointer if necessary. */
431 /* Move on the insert point. */
436 /* Terminate the list of dependencies and store the array address. */
439 needed[nneeded++] = NULL;
441 l->l_initfini = malloc (nneeded * sizeof needed[0]);
442 if (l->l_initfini == NULL)
443 _dl_signal_error (ENOMEM, map->l_name,
444 N_("cannot allocate dependency list"));
445 memcpy (l->l_initfini, needed, nneeded * sizeof needed[0]);
448 /* If we have no auxiliary objects just go on to the next map. */
452 while (runp != NULL && runp->done);
456 if (errno == 0 && errno_saved != 0)
457 __set_errno (errno_saved);
459 if (map->l_initfini != NULL && map->l_type == lt_loaded)
461 /* This object was previously loaded as a dependency and we have
462 a separate l_initfini list. We don't need it anymore. */
463 assert (map->l_searchlist.r_list == NULL);
464 free (map->l_initfini);
467 /* Store the search list we built in the object. It will be used for
468 searches in the scope of this object. */
470 (struct link_map **) malloc ((2 * nlist + 1)
471 * sizeof (struct link_map *));
472 if (map->l_initfini == NULL)
473 _dl_signal_error (ENOMEM, map->l_name,
474 N_("cannot allocate symbol search list"));
477 map->l_searchlist.r_list = &map->l_initfini[nlist + 1];
478 map->l_searchlist.r_nlist = nlist;
480 for (nlist = 0, runp = known; runp; runp = runp->next)
482 if (trace_mode && runp->map->l_faked)
483 /* This can happen when we trace the loading. */
484 --map->l_searchlist.r_nlist;
486 map->l_searchlist.r_list[nlist++] = runp->map;
488 /* Now clear all the mark bits we set in the objects on the search list
489 to avoid duplicates, so the next call starts fresh. */
490 runp->map->l_reserved = 0;
493 /* Now determine the order in which the initialization has to happen. */
494 memcpy (map->l_initfini, map->l_searchlist.r_list,
495 nlist * sizeof (struct link_map *));
496 /* We can skip looking for the binary itself which is at the front
497 of the search list. Look through the list backward so that circular
498 dependencies are not changing the order. */
499 for (i = 1; i < nlist; ++i)
501 struct link_map *l = map->l_searchlist.r_list[i];
505 /* Find the place in the initfini list where the map is currently
507 for (j = 1; map->l_initfini[j] != l; ++j)
510 /* Find all object for which the current one is a dependency and
511 move the found object (if necessary) in front. */
512 for (k = j + 1; k < nlist; ++k)
514 struct link_map **runp;
516 runp = map->l_initfini[k]->l_initfini;
519 while (*runp != NULL)
522 struct link_map *here = map->l_initfini[k];
525 memmove (&map->l_initfini[j] + 1,
527 (k - j) * sizeof (struct link_map *));
528 map->l_initfini[j] = here;
537 /* Terminate the list of dependencies. */
538 map->l_initfini[nlist] = NULL;
541 _dl_signal_error (errno_reason == -1 ? 0 : errno_reason,