1 /* Load the dependencies of a mapped object.
2 Copyright (C) 1996, 1997, 1998, 1999, 2000 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 two kinds paths
76 through the list of loaded shared objects. We have to
78 - produce a flat list with unique members of all involved objects
80 - produce a flat list of all shared objects.
84 int done; /* Nonzero if this map was processed. */
85 struct link_map *map; /* The data. */
87 struct list *unique; /* Elements for normal list. */
88 struct list *dup; /* Elements in complete list. */
92 /* Macro to expand DST. It is an macro since we use `alloca'. */
93 #define expand_dst(l, str, fatal) \
95 const char *__str = (str); \
96 const char *__result = __str; \
97 size_t __cnt = DL_DST_COUNT(__str, 0); \
103 /* DST must not appear in SUID/SGID programs. */ \
104 if (__libc_enable_secure) \
105 _dl_signal_error (0, __str, \
106 N_("DST not allowed in SUID/SGID programs")); \
108 __newp = (char *) alloca (DL_DST_REQUIRED (l, __str, strlen (__str), \
111 __result = DL_DST_SUBSTITUTE (l, __str, __newp, 0); \
113 if (*__result == '\0') \
115 /* The replacement for the DST is not known. We can't \
118 _dl_signal_error (0, __str, N_("\
119 empty dynamics string token substitution")); \
122 /* This is for DT_AUXILIARY. */ \
123 if (__builtin_expect (_dl_debug_libs, 0)) \
124 _dl_debug_message (1, "cannot load auxiliary `", __str, \
125 "' because of empty dynamic string" \
126 " token substitution\n", NULL); \
137 _dl_map_object_deps (struct link_map *map,
138 struct link_map **preloads, unsigned int npreloads,
141 struct list known[1 + npreloads + 1];
142 struct list *runp, *utail, *dtail;
143 unsigned int nlist, nduplist, i;
145 inline void preload (struct link_map *map)
147 known[nlist].done = 0;
148 known[nlist].map = map;
150 known[nlist].unique = &known[nlist + 1];
151 known[nlist].dup = &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].unique = NULL;
172 known[nlist - 1].dup = NULL;
174 /* Pointer to last unique object. */
175 utail = &known[nlist - 1];
176 /* Pointer to last loaded object. */
177 dtail = &known[nlist - 1];
179 /* Until now we have the same number of libraries in the normal and
180 the list with duplicates. */
183 /* Process each element of the search list, loading each of its
184 auxiliary objects and immediate dependencies. Auxiliary objects
185 will be added in the list before the object itself and
186 dependencies will be appended to the list as we step through it.
187 This produces a flat, ordered list that represents a
188 breadth-first search of the dependency tree.
190 The whole process is complicated by the fact that we better
191 should use alloca for the temporary list elements. But using
192 alloca means we cannot use recursive function calls. */
193 for (runp = known; runp; )
195 struct link_map *l = runp->map;
196 struct link_map **needed = NULL;
197 unsigned int nneeded = 0;
199 /* Unless otherwise stated, this object is handled. */
202 /* Allocate a temporary record to contain the references to the
203 dependencies of this object. */
204 if (l->l_searchlist.r_list == NULL && l->l_initfini == NULL
205 && l != map && l->l_ldnum > 0)
206 needed = (struct link_map **) alloca (l->l_ldnum
207 * sizeof (struct link_map *));
209 if (l->l_info[DT_NEEDED] || l->l_info[AUXTAG] || l->l_info[FILTERTAG])
211 const char *strtab = (const void *) D_PTR (l, l_info[DT_STRTAB]);
212 struct openaux_args args;
216 args.strtab = strtab;
218 args.trace_mode = trace_mode;
221 for (d = l->l_ld; d->d_tag != DT_NULL; ++d)
222 if (__builtin_expect (d->d_tag, DT_NEEDED) == DT_NEEDED)
224 /* Map in the needed object. */
225 struct link_map *dep;
226 /* Allocate new entry. */
231 /* Recognize DSTs. */
232 name = expand_dst (l, strtab + d->d_un.d_val, 0);
234 dep = _dl_map_object (l, name, 0,
235 l->l_type == lt_executable ? lt_library :
236 l->l_type, trace_mode, 0);
238 /* Add it in any case to the duplicate list. */
239 newp = alloca (sizeof (struct list));
246 if (! dep->l_reserved)
248 /* Append DEP to the unique list. */
251 utail->unique = newp;
254 /* Set the mark bit that says it's already in the list. */
258 /* Remember this dependency. */
260 needed[nneeded++] = dep;
262 else if (d->d_tag == DT_AUXILIARY || d->d_tag == DT_FILTER)
265 const char *errstring;
270 /* Recognize DSTs. */
271 name = expand_dst (l, strtab + d->d_un.d_val,
272 d->d_tag == DT_AUXILIARY);
274 if (d->d_tag == DT_AUXILIARY)
276 /* Store the tag in the argument structure. */
279 /* Say that we are about to load an auxiliary library. */
280 if (__builtin_expect (_dl_debug_libs, 0))
281 _dl_debug_message (1, "load auxiliary object=",
282 name, " requested by file=",
284 ? l->l_name : _dl_argv[0],
287 /* We must be prepared that the addressed shared
288 object is not available. */
289 if (_dl_catch_error (&objname, &errstring, openaux, &args))
291 /* We are not interested in the error message. */
292 assert (errstring != NULL);
293 if (errstring != _dl_out_of_memory)
294 free ((char *) errstring);
296 /* Simply ignore this error and continue the work. */
302 /* Say that we are about to load an auxiliary library. */
303 if (__builtin_expect (_dl_debug_libs, 0))
304 _dl_debug_message (1, "load filtered object=", name,
305 " requested by file=",
307 ? l->l_name : _dl_argv[0],
310 /* For filter objects the dependency must be available. */
311 args.aux = _dl_map_object (l, name, 0,
312 (l->l_type == lt_executable
313 ? lt_library : l->l_type),
317 /* The auxiliary object is actually available.
318 Incorporate the map in all the lists. */
320 /* Allocate new entry. This always has to be done. */
321 newp = alloca (sizeof (struct list));
323 /* We want to insert the new map before the current one,
324 but we have no back links. So we copy the contents of
325 the current entry over. Note that ORIG and NEWP now
326 have switched their meanings. */
327 orig->dup = memcpy (newp, orig, sizeof (*newp));
329 /* Initialize new entry. */
331 orig->map = args.aux;
333 /* Remember this dependency. */
335 needed[nneeded++] = args.aux;
337 /* We must handle two situations here: the map is new,
338 so we must add it in all three lists. If the map
339 is already known, we have two further possibilities:
340 - if the object is before the current map in the
341 search list, we do nothing. It is already found
343 - if the object is after the current one, we must
344 move it just before the current map to make sure
345 the symbols are found early enough
347 if (args.aux->l_reserved)
349 /* The object is already somewhere in the list.
353 /* This object is already in the search list we
354 are building. Don't add a duplicate pointer.
355 Just added by _dl_map_object. */
356 for (late = newp; late->unique; late = late->unique)
357 if (late->unique->map == args.aux)
362 /* The object is somewhere behind the current
363 position in the search path. We have to
364 move it to this earlier position. */
367 /* Now remove the later entry from the unique list
368 and adjust the tail pointer. */
369 if (utail == late->unique)
371 late->unique = late->unique->unique;
373 /* We must move the object earlier in the chain. */
374 if (args.aux->l_prev)
375 args.aux->l_prev->l_next = args.aux->l_next;
376 if (args.aux->l_next)
377 args.aux->l_next->l_prev = args.aux->l_prev;
379 args.aux->l_prev = newp->map->l_prev;
380 newp->map->l_prev = args.aux;
381 if (args.aux->l_prev != NULL)
382 args.aux->l_prev->l_next = args.aux;
383 args.aux->l_next = newp->map;
387 /* The object must be somewhere earlier in the
388 list. That's good, we only have to insert
389 an entry for the duplicate list. */
390 orig->unique = NULL; /* Never used. */
392 /* Now we have a problem. The element
393 pointing to ORIG in the unique list must
394 point to NEWP now. This is the only place
395 where we need this backreference and this
396 situation is really not that frequent. So
397 we don't use a double-linked list but
398 instead search for the preceding element. */
400 while (late->unique != orig)
407 /* This is easy. We just add the symbol right here. */
410 /* Set the mark bit that says it's already in the list. */
411 args.aux->l_reserved = 1;
413 /* The only problem is that in the double linked
414 list of all objects we don't have this new
415 object at the correct place. Correct this here. */
416 if (args.aux->l_prev)
417 args.aux->l_prev->l_next = args.aux->l_next;
418 if (args.aux->l_next)
419 args.aux->l_next->l_prev = args.aux->l_prev;
421 args.aux->l_prev = newp->map->l_prev;
422 newp->map->l_prev = args.aux;
423 if (args.aux->l_prev != NULL)
424 args.aux->l_prev->l_next = args.aux;
425 args.aux->l_next = newp->map;
428 /* Move the tail pointers if necessary. */
434 /* Move on the insert point. */
437 /* We always add an entry to the duplicate list. */
442 /* Terminate the list of dependencies and store the array address. */
445 needed[nneeded++] = NULL;
447 l->l_initfini = malloc (nneeded * sizeof needed[0]);
448 if (l->l_initfini == NULL)
449 _dl_signal_error (ENOMEM, map->l_name,
450 N_("cannot allocate dependency list"));
451 memcpy (l->l_initfini, needed, nneeded * sizeof needed[0]);
454 /* If we have no auxiliary objects just go on to the next map. */
458 while (runp != NULL && runp->done);
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 + (nlist == nduplist ? 0 : nduplist))
474 * sizeof (struct link_map *));
475 if (map->l_initfini == NULL)
476 _dl_signal_error (ENOMEM, map->l_name,
477 N_("cannot allocate symbol search list"));
480 map->l_searchlist.r_list = &map->l_initfini[nlist + 1];
481 map->l_searchlist.r_nlist = nlist;
483 for (nlist = 0, runp = known; runp; runp = runp->unique)
485 if (trace_mode && runp->map->l_faked)
486 /* This can happen when we trace the loading. */
487 --map->l_searchlist.r_nlist;
489 map->l_searchlist.r_list[nlist++] = runp->map;
491 /* Now clear all the mark bits we set in the objects on the search list
492 to avoid duplicates, so the next call starts fresh. */
493 runp->map->l_reserved = 0;
496 map->l_searchlist.r_nduplist = nduplist;
497 if (nlist == nduplist)
498 map->l_searchlist.r_duplist = map->l_searchlist.r_list;
503 map->l_searchlist.r_duplist = map->l_searchlist.r_list + nlist;
505 for (cnt = 0, runp = known; runp; runp = runp->dup)
506 if (trace_mode && runp->map->l_faked)
507 /* This can happen when we trace the loading. */
508 --map->l_searchlist.r_nduplist;
510 map->l_searchlist.r_duplist[cnt++] = runp->map;
513 /* Now determine the order in which the initialization has to happen. */
514 memcpy (map->l_initfini, map->l_searchlist.r_list,
515 nlist * sizeof (struct link_map *));
516 /* We can skip looking for the binary itself which is at the front
517 of the search list. Look through the list backward so that circular
518 dependencies are not changing the order. */
519 for (i = 1; i < nlist; ++i)
521 struct link_map *l = map->l_searchlist.r_list[i];
525 /* Find the place in the initfini list where the map is currently
527 for (j = 1; map->l_initfini[j] != l; ++j)
530 /* Find all object for which the current one is a dependency and
531 move the found object (if necessary) in front. */
532 for (k = j + 1; k < nlist; ++k)
534 struct link_map **runp;
536 runp = map->l_initfini[k]->l_initfini;
539 while (*runp != NULL)
542 struct link_map *here = map->l_initfini[k];
545 memmove (&map->l_initfini[j] + 1,
547 (k - j) * sizeof (struct link_map *));
548 map->l_initfini[j] = here;
557 /* Terminate the list of dependencies. */
558 map->l_initfini[nlist] = NULL;