1 /* Load a shared object at runtime, relocate it, and run its initializer.
2 Copyright (C) 1996-2004, 2005 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 Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the 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 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
28 #include <sys/mman.h> /* Check whether MAP_COPY is defined. */
29 #include <sys/param.h>
30 #include <bits/libc-lock.h>
38 extern ElfW(Addr) _dl_sysdep_start (void **start_argptr,
39 void (*dl_main) (const ElfW(Phdr) *phdr,
41 ElfW(Addr) *user_entry));
42 weak_extern (BP_SYM (_dl_sysdep_start))
44 extern int __libc_multiple_libcs; /* Defined in init-first.c. */
46 /* Undefine the following for debugging. */
47 /* #define SCOPE_DEBUG 1 */
49 static void show_scope (struct link_map *new);
52 /* We must be carefull not to leave us in an inconsistent state. Thus we
53 catch any error and re-raise it after cleaning up. */
59 /* This is the caller of the dlopen() function. */
60 const void *caller_dlopen;
61 /* This is the caller if _dl_open(). */
62 const void *caller_dl_open;
66 /* Original parameters to the program and the current environment. */
74 add_to_global (struct link_map *new)
76 struct link_map **new_global;
77 unsigned int to_add = 0;
80 /* Count the objects we have to put in the global scope. */
81 for (cnt = 0; cnt < new->l_searchlist.r_nlist; ++cnt)
82 if (new->l_searchlist.r_list[cnt]->l_global == 0)
85 /* The symbols of the new objects and its dependencies are to be
86 introduced into the global scope that will be used to resolve
87 references from other dynamically-loaded objects.
89 The global scope is the searchlist in the main link map. We
90 extend this list if necessary. There is one problem though:
91 since this structure was allocated very early (before the libc
92 is loaded) the memory it uses is allocated by the malloc()-stub
93 in the ld.so. When we come here these functions are not used
94 anymore. Instead the malloc() implementation of the libc is
95 used. But this means the block from the main map cannot be used
96 in an realloc() call. Therefore we allocate a completely new
97 array the first time we have to add something to the locale scope. */
99 if (GL(dl_ns)[new->l_ns]._ns_global_scope_alloc == 0)
101 /* This is the first dynamic object given global scope. */
102 GL(dl_ns)[new->l_ns]._ns_global_scope_alloc
103 = GL(dl_ns)[new->l_ns]._ns_main_searchlist->r_nlist + to_add + 8;
104 new_global = (struct link_map **)
105 malloc (GL(dl_ns)[new->l_ns]._ns_global_scope_alloc
106 * sizeof (struct link_map *));
107 if (new_global == NULL)
109 GL(dl_ns)[new->l_ns]._ns_global_scope_alloc = 0;
111 _dl_signal_error (ENOMEM, new->l_libname->name, NULL,
112 N_("cannot extend global scope"));
116 /* Copy over the old entries. */
117 GL(dl_ns)[new->l_ns]._ns_main_searchlist->r_list
118 = memcpy (new_global,
119 GL(dl_ns)[new->l_ns]._ns_main_searchlist->r_list,
120 (GL(dl_ns)[new->l_ns]._ns_main_searchlist->r_nlist
121 * sizeof (struct link_map *)));
123 else if (GL(dl_ns)[new->l_ns]._ns_main_searchlist->r_nlist + to_add
124 > GL(dl_ns)[new->l_ns]._ns_global_scope_alloc)
126 /* We have to extend the existing array of link maps in the
128 new_global = (struct link_map **)
129 realloc (GL(dl_ns)[new->l_ns]._ns_main_searchlist->r_list,
130 ((GL(dl_ns)[new->l_ns]._ns_global_scope_alloc + to_add + 8)
131 * sizeof (struct link_map *)));
132 if (new_global == NULL)
135 GL(dl_ns)[new->l_ns]._ns_global_scope_alloc += to_add + 8;
136 GL(dl_ns)[new->l_ns]._ns_main_searchlist->r_list = new_global;
139 /* Now add the new entries. */
140 for (cnt = 0; cnt < new->l_searchlist.r_nlist; ++cnt)
142 struct link_map *map = new->l_searchlist.r_list[cnt];
144 if (map->l_global == 0)
147 GL(dl_ns)[new->l_ns]._ns_main_searchlist->r_list[GL(dl_ns)[new->l_ns]._ns_main_searchlist->r_nlist]
149 ++GL(dl_ns)[new->l_ns]._ns_main_searchlist->r_nlist;
158 dl_open_worker (void *a)
160 struct dl_open_args *args = a;
161 const char *file = args->file;
162 int mode = args->mode;
163 struct link_map *new, *l;
167 bool any_tls = false;
169 struct link_map *call_map = NULL;
171 /* Check whether _dl_open() has been called from a valid DSO. */
172 if (__check_caller (args->caller_dl_open,
173 allow_libc|allow_libdl|allow_ldso) != 0)
174 _dl_signal_error (0, "dlopen", NULL, N_("invalid caller"));
176 /* Determine the caller's map if necessary. This is needed in case
177 we have a DST, when we don't know the namespace ID we have to put
178 the new object in, or when the file name has no path in which
179 case we need to look along the RUNPATH/RPATH of the caller. */
180 const char *dst = strchr (file, '$');
181 if (dst != NULL || args->nsid == __LM_ID_CALLER
182 || strchr (file, '/') == NULL)
184 const void *caller_dlopen = args->caller_dlopen;
186 /* We have to find out from which object the caller is calling.
187 By default we assume this is the main application. */
188 call_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
190 for (Lmid_t ns = 0; ns < DL_NNS; ++ns)
191 for (l = GL(dl_ns)[ns]._ns_loaded; l != NULL; l = l->l_next)
192 if (caller_dlopen >= (const void *) l->l_map_start
193 && caller_dlopen < (const void *) l->l_map_end)
195 /* There must be exactly one DSO for the range of the virtual
196 memory. Otherwise something is really broken. */
197 assert (ns == l->l_ns);
203 if (args->nsid == __LM_ID_CALLER)
206 /* In statically linked apps there might be no loaded object. */
207 if (call_map == NULL)
208 args->nsid = LM_ID_BASE;
211 args->nsid = call_map->l_ns;
215 assert (_dl_debug_initialize (0, args->nsid)->r_state == RT_CONSISTENT);
217 /* Maybe we have to expand a DST. */
218 if (__builtin_expect (dst != NULL, 0))
220 size_t len = strlen (file);
224 /* DSTs must not appear in SUID/SGID programs. */
225 if (INTUSE(__libc_enable_secure))
226 /* This is an error. */
227 _dl_signal_error (0, "dlopen", NULL,
228 N_("DST not allowed in SUID/SGID programs"));
231 /* Determine how much space we need. We have to allocate the
233 required = DL_DST_REQUIRED (call_map, file, len, _dl_dst_count (dst, 0));
235 /* Get space for the new file name. */
236 new_file = (char *) alloca (required + 1);
238 /* Generate the new file name. */
239 _dl_dst_substitute (call_map, file, new_file, 0);
241 /* If the substitution failed don't try to load. */
242 if (*new_file == '\0')
243 _dl_signal_error (0, "dlopen", NULL,
244 N_("empty dynamic string token substitution"));
246 /* Now we have a new file name. */
249 /* It does not matter whether call_map is set even if we
250 computed it only because of the DST. Since the path contains
251 a slash the value is not used. See dl-load.c. */
254 /* Load the named object. */
255 args->map = new = _dl_map_object (call_map, file, 0, lt_loaded, 0,
256 mode | __RTLD_CALLMAP, args->nsid);
258 /* If the pointer returned is NULL this means the RTLD_NOLOAD flag is
259 set and the object is not already loaded. */
262 assert (mode & RTLD_NOLOAD);
266 if (__builtin_expect (mode & __RTLD_SPROF, 0))
267 /* This happens only if we load a DSO for 'sprof'. */
270 /* This object is directly loaded. */
271 ++new->l_direct_opencount;
273 /* It was already open. */
274 if (__builtin_expect (new->l_searchlist.r_list != NULL, 0))
276 /* Let the user know about the opencount. */
277 if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_FILES, 0))
278 _dl_debug_printf ("opening file=%s [%lu]; direct_opencount=%u\n\n",
279 new->l_name, new->l_ns, new->l_direct_opencount);
281 /* If the user requested the object to be in the global namespace
282 but it is not so far, add it now. */
283 if ((mode & RTLD_GLOBAL) && new->l_global == 0)
284 (void) add_to_global (new);
286 assert (_dl_debug_initialize (0, args->nsid)->r_state == RT_CONSISTENT);
291 /* Load that object's dependencies. */
292 _dl_map_object_deps (new, NULL, 0, 0,
293 mode & (__RTLD_DLOPEN | RTLD_DEEPBIND | __RTLD_AUDIT));
295 /* So far, so good. Now check the versions. */
296 for (i = 0; i < new->l_searchlist.r_nlist; ++i)
297 if (new->l_searchlist.r_list[i]->l_real->l_versions == NULL)
298 (void) _dl_check_map_versions (new->l_searchlist.r_list[i]->l_real,
306 /* Auditing checkpoint: we have added all objects. */
307 if (__builtin_expect (GLRO(dl_naudit) > 0, 0))
309 struct link_map *head = GL(dl_ns)[new->l_ns]._ns_loaded;
310 /* Do not call the functions for any auditing object. */
311 if (head->l_auditing == 0)
313 struct audit_ifaces *afct = GLRO(dl_audit);
314 for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
316 if (afct->activity != NULL)
317 afct->activity (&head->l_audit[cnt].cookie, LA_ACT_CONSISTENT);
325 /* Notify the debugger all new objects are now ready to go. */
326 struct r_debug *r = _dl_debug_initialize (0, args->nsid);
327 r->r_state = RT_CONSISTENT;
330 /* Only do lazy relocation if `LD_BIND_NOW' is not set. */
331 lazy = (mode & RTLD_BINDING_MASK) == RTLD_LAZY && GLRO(dl_lazy);
333 /* Relocate the objects loaded. We do this in reverse order so that copy
334 relocs of earlier objects overwrite the data written by later objects. */
341 if (! l->l_real->l_relocated)
344 if (GLRO(dl_profile) != NULL)
346 /* If this here is the shared object which we want to profile
347 make sure the profile is started. We can find out whether
348 this is necessary or not by observing the `_dl_profile_map'
349 variable. If was NULL but is not NULL afterwars we must
350 start the profiling. */
351 struct link_map *old_profile_map = GL(dl_profile_map);
353 _dl_relocate_object (l, l->l_scope, 1, 1);
355 if (old_profile_map == NULL && GL(dl_profile_map) != NULL)
357 /* We must prepare the profiling. */
358 _dl_start_profile ();
360 /* Prevent unloading the object. */
361 GL(dl_profile_map)->l_flags_1 |= DF_1_NODELETE;
366 _dl_relocate_object (l, l->l_scope, lazy, 0);
374 /* If the file is not loaded now as a dependency, add the search
375 list of the newly loaded object to the scope. */
376 for (i = 0; i < new->l_searchlist.r_nlist; ++i)
378 struct link_map *imap = new->l_searchlist.r_list[i];
380 /* If the initializer has been called already, the object has
381 not been loaded here and now. */
382 if (imap->l_init_called && imap->l_type == lt_loaded)
384 struct r_scope_elem **runp = imap->l_scope;
387 while (*runp != NULL)
394 /* Avoid duplicates. */
397 if (__builtin_expect (cnt + 1 >= imap->l_scope_max, 0))
399 /* The 'r_scope' array is too small. Allocate a new one
401 struct r_scope_elem **newp;
402 size_t new_size = imap->l_scope_max * 2;
404 if (imap->l_scope == imap->l_scope_mem)
406 newp = (struct r_scope_elem **)
407 malloc (new_size * sizeof (struct r_scope_elem *));
409 _dl_signal_error (ENOMEM, "dlopen", NULL,
410 N_("cannot create scope list"));
411 imap->l_scope = memcpy (newp, imap->l_scope,
412 cnt * sizeof (imap->l_scope[0]));
416 newp = (struct r_scope_elem **)
417 realloc (imap->l_scope,
418 new_size * sizeof (struct r_scope_elem *));
420 _dl_signal_error (ENOMEM, "dlopen", NULL,
421 N_("cannot create scope list"));
422 imap->l_scope = newp;
425 imap->l_scope_max = new_size;
428 imap->l_scope[cnt++] = &new->l_searchlist;
429 imap->l_scope[cnt] = NULL;
432 /* Only add TLS memory if this object is loaded now and
433 therefore is not yet initialized. */
434 else if (! imap->l_init_called
435 /* Only if the module defines thread local data. */
436 && __builtin_expect (imap->l_tls_blocksize > 0, 0))
438 /* Now that we know the object is loaded successfully add
439 modules containing TLS data to the slot info table. We
440 might have to increase its size. */
441 _dl_add_to_slotinfo (imap);
443 if (imap->l_need_tls_init)
445 imap->l_need_tls_init = 0;
447 /* Update the slot information data for at least the
448 generation of the DSO we are allocating data for. */
449 _dl_update_slotinfo (imap->l_tls_modid);
452 GL(dl_init_static_tls) (imap);
453 assert (imap->l_need_tls_init == 0);
456 /* We have to bump the generation counter. */
463 /* Bump the generation number if necessary. */
464 if (any_tls && __builtin_expect (++GL(dl_tls_generation) == 0, 0))
465 _dl_fatal_printf (N_("\
466 TLS generation counter wrapped! Please report this."));
469 /* Run the initializer functions of new objects. */
470 _dl_init (new, args->argc, args->argv, args->env);
472 /* Now we can make the new map available in the global scope. */
473 if (mode & RTLD_GLOBAL)
474 /* Move the object in the global namespace. */
475 if (add_to_global (new) != 0)
479 /* Mark the object as not deletable if the RTLD_NODELETE flags was
481 if (__builtin_expect (mode & RTLD_NODELETE, 0))
482 new->l_flags_1 |= DF_1_NODELETE;
485 /* We must be the static _dl_open in libc.a. A static program that
486 has loaded a dynamic object now has competition. */
487 __libc_multiple_libcs = 1;
490 /* Let the user know about the opencount. */
491 if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_FILES, 0))
492 _dl_debug_printf ("opening file=%s [%lu]; direct_opencount=%u\n\n",
493 new->l_name, new->l_ns, new->l_direct_opencount);
498 _dl_open (const char *file, int mode, const void *caller_dlopen, Lmid_t nsid,
499 int argc, char *argv[], char *env[])
501 if ((mode & RTLD_BINDING_MASK) == 0)
502 /* One of the flags must be set. */
503 _dl_signal_error (EINVAL, file, NULL, N_("invalid mode for dlopen()"));
505 /* Make sure we are alone. */
506 __rtld_lock_lock_recursive (GL(dl_load_lock));
508 if (nsid == LM_ID_NEWLM)
510 /* Find a new namespace. */
511 for (nsid = 1; nsid < DL_NNS; ++nsid)
512 if (GL(dl_ns)[nsid]._ns_loaded == NULL)
517 /* No more namespace available. */
518 __rtld_lock_unlock_recursive (GL(dl_load_lock));
520 _dl_signal_error (EINVAL, file, NULL, N_("\
521 no more namespaces available for dlmopen()"));
524 _dl_debug_initialize (0, nsid)->r_state = RT_CONSISTENT;
526 /* Never allow loading a DSO in a namespace which is empty. Such
527 direct placements is only causing problems. Also don't allow
528 loading into a namespace used for auditing. */
529 else if (nsid != LM_ID_BASE && nsid != __LM_ID_CALLER
530 && (GL(dl_ns)[nsid]._ns_nloaded == 0
531 || GL(dl_ns)[nsid]._ns_loaded->l_auditing))
532 _dl_signal_error (EINVAL, file, NULL,
533 N_("invalid target namespace in dlmopen()"));
535 struct dl_open_args args;
538 args.caller_dlopen = caller_dlopen;
539 args.caller_dl_open = RETURN_ADDRESS (0);
547 const char *errstring;
549 int errcode = _dl_catch_error (&objname, &errstring, &malloced,
550 dl_open_worker, &args);
553 /* We must munmap() the cache file. */
557 /* Release the lock. */
558 __rtld_lock_unlock_recursive (GL(dl_load_lock));
560 if (__builtin_expect (errstring != NULL, 0))
562 /* Some error occurred during loading. */
563 char *local_errstring;
564 size_t len_errstring;
566 /* Remove the object from memory. It may be in an inconsistent
567 state if relocation failed, for example. */
571 /* Maybe some of the modules which were loaded use TLS.
572 Since it will be removed in the following _dl_close call
573 we have to mark the dtv array as having gaps to fill the
574 holes. This is a pessimistic assumption which won't hurt
575 if not true. There is no need to do this when we are
576 loading the auditing DSOs since TLS has not yet been set
578 if ((mode & __RTLD_AUDIT) == 0)
579 GL(dl_tls_dtv_gaps) = true;
582 _dl_close (args.map);
585 /* Make a local copy of the error string so that we can release the
586 memory allocated for it. */
587 len_errstring = strlen (errstring) + 1;
588 if (objname == errstring + len_errstring)
590 size_t total_len = len_errstring + strlen (objname) + 1;
591 local_errstring = alloca (total_len);
592 memcpy (local_errstring, errstring, total_len);
593 objname = local_errstring + len_errstring;
597 local_errstring = alloca (len_errstring);
598 memcpy (local_errstring, errstring, len_errstring);
602 free ((char *) errstring);
604 assert (_dl_debug_initialize (0, args.nsid)->r_state == RT_CONSISTENT);
606 /* Reraise the error. */
607 _dl_signal_error (errcode, objname, NULL, local_errstring);
610 assert (_dl_debug_initialize (0, args.nsid)->r_state == RT_CONSISTENT);
613 DL_STATIC_INIT (args.map);
624 show_scope (struct link_map *new)
628 for (scope_cnt = 0; new->l_scope[scope_cnt] != NULL; ++scope_cnt)
633 numbuf[0] = '0' + scope_cnt;
635 _dl_printf ("scope %s:", numbuf);
637 for (cnt = 0; cnt < new->l_scope[scope_cnt]->r_nlist; ++cnt)
638 if (*new->l_scope[scope_cnt]->r_list[cnt]->l_name)
639 _dl_printf (" %s", new->l_scope[scope_cnt]->r_list[cnt]->l_name);
641 _dl_printf (" <main>");