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;
145 auto inline void preload (struct link_map *map);
147 inline void preload (struct link_map *map)
149 known[nlist].done = 0;
150 known[nlist].map = map;
151 known[nlist].next = &known[nlist + 1];
154 /* We use `l_reserved' as a mark bit to detect objects we have
155 already put in the search list and avoid adding duplicate
156 elements later in the list. */
160 /* No loaded object so far. */
163 /* First load MAP itself. */
166 /* Add the preloaded items after MAP but before any of its dependencies. */
167 for (i = 0; i < npreloads; ++i)
168 preload (preloads[i]);
170 /* Terminate the lists. */
171 known[nlist - 1].next = NULL;
173 /* Pointer to last unique object. */
174 tail = &known[nlist - 1];
176 /* Process each element of the search list, loading each of its
177 auxiliary objects and immediate dependencies. Auxiliary objects
178 will be added in the list before the object itself and
179 dependencies will be appended to the list as we step through it.
180 This produces a flat, ordered list that represents a
181 breadth-first search of the dependency tree.
183 The whole process is complicated by the fact that we better
184 should use alloca for the temporary list elements. But using
185 alloca means we cannot use recursive function calls. */
191 for (runp = known; runp; )
193 struct link_map *l = runp->map;
194 struct link_map **needed = NULL;
195 unsigned int nneeded = 0;
197 /* Unless otherwise stated, this object is handled. */
200 /* Allocate a temporary record to contain the references to the
201 dependencies of this object. */
202 if (l->l_searchlist.r_list == NULL && l->l_initfini == NULL
203 && l != map && l->l_ldnum > 0)
204 needed = (struct link_map **) alloca (l->l_ldnum
205 * sizeof (struct link_map *));
207 if (l->l_info[DT_NEEDED] || l->l_info[AUXTAG] || l->l_info[FILTERTAG])
209 const char *strtab = (const void *) D_PTR (l, l_info[DT_STRTAB]);
210 struct openaux_args args;
214 args.strtab = strtab;
216 args.trace_mode = trace_mode;
219 for (d = l->l_ld; d->d_tag != DT_NULL; ++d)
220 if (__builtin_expect (d->d_tag, DT_NEEDED) == DT_NEEDED)
222 /* Map in the needed object. */
223 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)
269 /* Recognize DSTs. */
270 name = expand_dst (l, strtab + d->d_un.d_val,
271 d->d_tag == DT_AUXILIARY);
272 /* Store the tag in the argument structure. */
275 if (d->d_tag == DT_AUXILIARY)
277 /* Say that we are about to load an auxiliary library. */
278 if (__builtin_expect (_dl_debug_mask & DL_DEBUG_LIBS, 0))
279 _dl_debug_printf ("load auxiliary object=%s"
280 " requested by file=%s\n", name,
282 ? l->l_name : _dl_argv[0]);
284 /* We must be prepared that the addressed shared
285 object is not available. */
286 if (_dl_catch_error (&objname, &errstring, openaux, &args))
288 /* We are not interested in the error message. */
289 assert (errstring != NULL);
290 if (errstring != _dl_out_of_memory)
291 free ((char *) errstring);
294 /* Simply ignore this error and continue the work. */
300 /* Say that we are about to load an auxiliary library. */
301 if (__builtin_expect (_dl_debug_mask & DL_DEBUG_LIBS, 0))
302 _dl_debug_printf ("load filtered object=%s"
303 " requested by file=%s\n", name,
305 ? l->l_name : _dl_argv[0]);
307 /* For filter objects the dependency must be available. */
308 if (_dl_catch_error (&objname, &errstring, openaux, &args))
311 errno_reason = errno;
318 /* The auxiliary object is actually available.
319 Incorporate the map in all the lists. */
321 /* Allocate new entry. This always has to be done. */
322 newp = alloca (sizeof (struct list));
324 /* We want to insert the new map before the current one,
325 but we have no back links. So we copy the contents of
326 the current entry over. Note that ORIG and NEWP now
327 have switched their meanings. */
328 memcpy (newp, orig, sizeof (*newp));
330 /* Initialize new entry. */
332 orig->map = args.aux;
334 /* Remember this dependency. */
336 needed[nneeded++] = args.aux;
338 /* We must handle two situations here: the map is new,
339 so we must add it in all three lists. If the map
340 is already known, we have two further possibilities:
341 - if the object is before the current map in the
342 search list, we do nothing. It is already found
344 - if the object is after the current one, we must
345 move it just before the current map to make sure
346 the symbols are found early enough
348 if (args.aux->l_reserved)
350 /* The object is already somewhere in the list.
354 /* This object is already in the search list we
355 are building. Don't add a duplicate pointer.
356 Just added by _dl_map_object. */
357 for (late = newp; late->next; late = late->next)
358 if (late->next->map == args.aux)
363 /* The object is somewhere behind the current
364 position in the search path. We have to
365 move it to this earlier position. */
368 /* Now remove the later entry from the list
369 and adjust the tail pointer. */
370 if (tail == late->next)
372 late->next = late->next->next;
374 /* We must move the object earlier in the chain. */
375 if (args.aux->l_prev)
376 args.aux->l_prev->l_next = args.aux->l_next;
377 if (args.aux->l_next)
378 args.aux->l_next->l_prev = args.aux->l_prev;
380 args.aux->l_prev = newp->map->l_prev;
381 newp->map->l_prev = args.aux;
382 if (args.aux->l_prev != NULL)
383 args.aux->l_prev->l_next = args.aux;
384 args.aux->l_next = newp->map;
388 /* The object must be somewhere earlier in the
389 list. That's good, we only have to insert
390 an entry for the duplicate list. */
391 orig->next = NULL; /* Never used. */
393 /* Now we have a problem. The element
394 pointing to ORIG in the list must
395 point to NEWP now. This is the only place
396 where we need this backreference and this
397 situation is really not that frequent. So
398 we don't use a double-linked list but
399 instead search for the preceding element. */
401 while (late->next != orig)
408 /* This is easy. We just add the symbol right here. */
411 /* Set the mark bit that says it's already in the list. */
412 args.aux->l_reserved = 1;
414 /* The only problem is that in the double linked
415 list of all objects we don't have this new
416 object at the correct place. Correct this here. */
417 if (args.aux->l_prev)
418 args.aux->l_prev->l_next = args.aux->l_next;
419 if (args.aux->l_next)
420 args.aux->l_next->l_prev = args.aux->l_prev;
422 args.aux->l_prev = newp->map->l_prev;
423 newp->map->l_prev = args.aux;
424 if (args.aux->l_prev != NULL)
425 args.aux->l_prev->l_next = args.aux;
426 args.aux->l_next = newp->map;
429 /* Move the tail pointer if necessary. */
433 /* Move on the insert point. */
438 /* Terminate the list of dependencies and store the array address. */
441 needed[nneeded++] = NULL;
443 l->l_initfini = malloc (nneeded * sizeof needed[0]);
444 if (l->l_initfini == NULL)
445 _dl_signal_error (ENOMEM, map->l_name,
446 N_("cannot allocate dependency list"));
447 memcpy (l->l_initfini, needed, nneeded * sizeof needed[0]);
450 /* If we have no auxiliary objects just go on to the next map. */
454 while (runp != NULL && runp->done);
458 if (errno == 0 && errno_saved != 0)
459 __set_errno (errno_saved);
461 if (map->l_initfini != NULL && map->l_type == lt_loaded)
463 /* This object was previously loaded as a dependency and we have
464 a separate l_initfini list. We don't need it anymore. */
465 assert (map->l_searchlist.r_list == NULL);
466 free (map->l_initfini);
469 /* Store the search list we built in the object. It will be used for
470 searches in the scope of this object. */
472 (struct link_map **) malloc ((2 * nlist + 1)
473 * sizeof (struct link_map *));
474 if (map->l_initfini == NULL)
475 _dl_signal_error (ENOMEM, map->l_name,
476 N_("cannot allocate symbol search list"));
479 map->l_searchlist.r_list = &map->l_initfini[nlist + 1];
480 map->l_searchlist.r_nlist = nlist;
482 for (nlist = 0, runp = known; runp; runp = runp->next)
484 if (trace_mode && runp->map->l_faked)
485 /* This can happen when we trace the loading. */
486 --map->l_searchlist.r_nlist;
488 map->l_searchlist.r_list[nlist++] = runp->map;
490 /* Now clear all the mark bits we set in the objects on the search list
491 to avoid duplicates, so the next call starts fresh. */
492 runp->map->l_reserved = 0;
495 /* Now determine the order in which the initialization has to happen. */
496 memcpy (map->l_initfini, map->l_searchlist.r_list,
497 nlist * sizeof (struct link_map *));
498 /* We can skip looking for the binary itself which is at the front
499 of the search list. Look through the list backward so that circular
500 dependencies are not changing the order. */
501 for (i = 1; i < nlist; ++i)
503 struct link_map *l = map->l_searchlist.r_list[i];
507 /* Find the place in the initfini list where the map is currently
509 for (j = 1; map->l_initfini[j] != l; ++j)
512 /* Find all object for which the current one is a dependency and
513 move the found object (if necessary) in front. */
514 for (k = j + 1; k < nlist; ++k)
516 struct link_map **runp;
518 runp = map->l_initfini[k]->l_initfini;
521 while (*runp != NULL)
524 struct link_map *here = map->l_initfini[k];
527 memmove (&map->l_initfini[j] + 1,
529 (k - j) * sizeof (struct link_map *));
530 map->l_initfini[j] = here;
539 /* Terminate the list of dependencies. */
540 map->l_initfini[nlist] = NULL;
543 _dl_signal_error (errno_reason == -1 ? 0 : errno_reason,
544 errstring ?: "", N_("cannot load shared object file"));