1 /* Load a shared object at runtime, relocate it, and run its initializer.
2 Copyright (C) 1996-2007, 2009, 2010, 2011, 2012 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>
34 #include <sysdep-cancel.h>
40 extern ElfW(Addr) _dl_sysdep_start (void **start_argptr,
41 void (*dl_main) (const ElfW(Phdr) *phdr,
43 ElfW(Addr) *user_entry,
45 weak_extern (BP_SYM (_dl_sysdep_start))
47 extern int __libc_multiple_libcs; /* Defined in init-first.c. */
49 /* We must be carefull not to leave us in an inconsistent state. Thus we
50 catch any error and re-raise it after cleaning up. */
56 /* This is the caller of the dlopen() function. */
57 const void *caller_dlopen;
58 /* This is the caller if _dl_open(). */
59 const void *caller_dl_open;
63 /* Original parameters to the program and the current environment. */
71 add_to_global (struct link_map *new)
73 struct link_map **new_global;
74 unsigned int to_add = 0;
77 /* Count the objects we have to put in the global scope. */
78 for (cnt = 0; cnt < new->l_searchlist.r_nlist; ++cnt)
79 if (new->l_searchlist.r_list[cnt]->l_global == 0)
82 /* The symbols of the new objects and its dependencies are to be
83 introduced into the global scope that will be used to resolve
84 references from other dynamically-loaded objects.
86 The global scope is the searchlist in the main link map. We
87 extend this list if necessary. There is one problem though:
88 since this structure was allocated very early (before the libc
89 is loaded) the memory it uses is allocated by the malloc()-stub
90 in the ld.so. When we come here these functions are not used
91 anymore. Instead the malloc() implementation of the libc is
92 used. But this means the block from the main map cannot be used
93 in an realloc() call. Therefore we allocate a completely new
94 array the first time we have to add something to the locale scope. */
96 struct link_namespaces *ns = &GL(dl_ns)[new->l_ns];
97 if (ns->_ns_global_scope_alloc == 0)
99 /* This is the first dynamic object given global scope. */
100 ns->_ns_global_scope_alloc
101 = ns->_ns_main_searchlist->r_nlist + to_add + 8;
102 new_global = (struct link_map **)
103 malloc (ns->_ns_global_scope_alloc * sizeof (struct link_map *));
104 if (new_global == NULL)
106 ns->_ns_global_scope_alloc = 0;
108 _dl_signal_error (ENOMEM, new->l_libname->name, NULL,
109 N_("cannot extend global scope"));
113 /* Copy over the old entries. */
114 ns->_ns_main_searchlist->r_list
115 = memcpy (new_global, ns->_ns_main_searchlist->r_list,
116 (ns->_ns_main_searchlist->r_nlist
117 * sizeof (struct link_map *)));
119 else if (ns->_ns_main_searchlist->r_nlist + to_add
120 > ns->_ns_global_scope_alloc)
122 /* We have to extend the existing array of link maps in the
124 struct link_map **old_global
125 = GL(dl_ns)[new->l_ns]._ns_main_searchlist->r_list;
126 size_t new_nalloc = ((ns->_ns_global_scope_alloc + to_add) * 2);
128 new_global = (struct link_map **)
129 malloc (new_nalloc * sizeof (struct link_map *));
130 if (new_global == NULL)
133 memcpy (new_global, old_global,
134 ns->_ns_global_scope_alloc * sizeof (struct link_map *));
136 ns->_ns_global_scope_alloc = new_nalloc;
137 ns->_ns_main_searchlist->r_list = new_global;
139 if (!RTLD_SINGLE_THREAD_P)
140 THREAD_GSCOPE_WAIT ();
145 /* Now add the new entries. */
146 unsigned int new_nlist = ns->_ns_main_searchlist->r_nlist;
147 for (cnt = 0; cnt < new->l_searchlist.r_nlist; ++cnt)
149 struct link_map *map = new->l_searchlist.r_list[cnt];
151 if (map->l_global == 0)
154 ns->_ns_main_searchlist->r_list[new_nlist++] = map;
156 /* We modify the global scope. Report this. */
157 if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_SCOPES, 0))
158 _dl_debug_printf ("\nadd %s [%lu] to global scope\n",
159 map->l_name, map->l_ns);
162 atomic_write_barrier ();
163 ns->_ns_main_searchlist->r_nlist = new_nlist;
169 dl_open_worker (void *a)
171 struct dl_open_args *args = a;
172 const char *file = args->file;
173 int mode = args->mode;
174 struct link_map *call_map = NULL;
176 /* Check whether _dl_open() has been called from a valid DSO. */
177 if (__check_caller (args->caller_dl_open,
178 allow_libc|allow_libdl|allow_ldso) != 0)
179 _dl_signal_error (0, "dlopen", NULL, N_("invalid caller"));
181 /* Determine the caller's map if necessary. This is needed in case
182 we have a DST, when we don't know the namespace ID we have to put
183 the new object in, or when the file name has no path in which
184 case we need to look along the RUNPATH/RPATH of the caller. */
185 const char *dst = strchr (file, '$');
186 if (dst != NULL || args->nsid == __LM_ID_CALLER
187 || strchr (file, '/') == NULL)
189 const void *caller_dlopen = args->caller_dlopen;
191 /* We have to find out from which object the caller is calling.
192 By default we assume this is the main application. */
193 call_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
196 for (Lmid_t ns = 0; ns < GL(dl_nns); ++ns)
197 for (l = GL(dl_ns)[ns]._ns_loaded; l != NULL; l = l->l_next)
198 if (caller_dlopen >= (const void *) l->l_map_start
199 && caller_dlopen < (const void *) l->l_map_end
201 || _dl_addr_inside_object (l, (ElfW(Addr)) caller_dlopen)))
203 assert (ns == l->l_ns);
209 if (args->nsid == __LM_ID_CALLER)
212 /* In statically linked apps there might be no loaded object. */
213 if (call_map == NULL)
214 args->nsid = LM_ID_BASE;
217 args->nsid = call_map->l_ns;
221 assert (_dl_debug_initialize (0, args->nsid)->r_state == RT_CONSISTENT);
223 /* Load the named object. */
224 struct link_map *new;
225 args->map = new = _dl_map_object (call_map, file, lt_loaded, 0,
226 mode | __RTLD_CALLMAP, args->nsid);
228 /* If the pointer returned is NULL this means the RTLD_NOLOAD flag is
229 set and the object is not already loaded. */
232 assert (mode & RTLD_NOLOAD);
236 if (__builtin_expect (mode & __RTLD_SPROF, 0))
237 /* This happens only if we load a DSO for 'sprof'. */
240 /* This object is directly loaded. */
241 ++new->l_direct_opencount;
243 /* It was already open. */
244 if (__builtin_expect (new->l_searchlist.r_list != NULL, 0))
246 /* Let the user know about the opencount. */
247 if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_FILES, 0))
248 _dl_debug_printf ("opening file=%s [%lu]; direct_opencount=%u\n\n",
249 new->l_name, new->l_ns, new->l_direct_opencount);
251 /* If the user requested the object to be in the global namespace
252 but it is not so far, add it now. */
253 if ((mode & RTLD_GLOBAL) && new->l_global == 0)
254 (void) add_to_global (new);
256 assert (_dl_debug_initialize (0, args->nsid)->r_state == RT_CONSISTENT);
261 /* Load that object's dependencies. */
262 _dl_map_object_deps (new, NULL, 0, 0,
263 mode & (__RTLD_DLOPEN | RTLD_DEEPBIND | __RTLD_AUDIT));
265 /* So far, so good. Now check the versions. */
266 for (unsigned int i = 0; i < new->l_searchlist.r_nlist; ++i)
267 if (new->l_searchlist.r_list[i]->l_real->l_versions == NULL)
268 (void) _dl_check_map_versions (new->l_searchlist.r_list[i]->l_real,
272 /* Auditing checkpoint: we have added all objects. */
273 if (__builtin_expect (GLRO(dl_naudit) > 0, 0))
275 struct link_map *head = GL(dl_ns)[new->l_ns]._ns_loaded;
276 /* Do not call the functions for any auditing object. */
277 if (head->l_auditing == 0)
279 struct audit_ifaces *afct = GLRO(dl_audit);
280 for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
282 if (afct->activity != NULL)
283 afct->activity (&head->l_audit[cnt].cookie, LA_ACT_CONSISTENT);
291 /* Notify the debugger all new objects are now ready to go. */
292 struct r_debug *r = _dl_debug_initialize (0, args->nsid);
293 r->r_state = RT_CONSISTENT;
296 /* Print scope information. */
297 if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_SCOPES, 0))
298 _dl_show_scope (new, 0);
300 /* Only do lazy relocation if `LD_BIND_NOW' is not set. */
301 int reloc_mode = mode & __RTLD_AUDIT;
303 reloc_mode |= mode & RTLD_LAZY;
305 /* Sort the objects by dependency for the relocation process. This
306 allows IFUNC relocations to work and it also means copy
307 relocation of dependencies are if necessary overwritten. */
309 struct link_map *l = new;
312 if (! l->l_real->l_relocated)
317 struct link_map *maps[nmaps];
322 if (! l->l_real->l_relocated)
330 memset (seen, '\0', nmaps);
335 struct link_map *thisp = maps[i];
337 /* Find the last object in the list for which the current one is
338 a dependency and move the current object behind the object
339 with the dependency. */
340 size_t k = nmaps - 1;
343 struct link_map **runp = maps[k]->l_initfini;
345 /* Look through the dependencies of the object. */
346 while (*runp != NULL)
347 if (__builtin_expect (*runp++ == thisp, 0))
349 /* Move the current object to the back past the last
350 object with it as the dependency. */
351 memmove (&maps[i], &maps[i + 1],
352 (k - i) * sizeof (maps[0]));
361 char this_seen = seen[i];
362 memmove (&seen[i], &seen[i + 1],
363 (k - i) * sizeof (seen[0]));
375 memset (&seen[i], 0, (nmaps - i) * sizeof (seen[0]));
380 for (size_t i = nmaps; i-- > 0; )
385 if (__builtin_expect (GLRO(dl_profile) != NULL, 0))
387 /* If this here is the shared object which we want to profile
388 make sure the profile is started. We can find out whether
389 this is necessary or not by observing the `_dl_profile_map'
390 variable. If it was NULL but is not NULL afterwars we must
391 start the profiling. */
392 struct link_map *old_profile_map = GL(dl_profile_map);
394 _dl_relocate_object (l, l->l_scope, reloc_mode | RTLD_LAZY, 1);
396 if (old_profile_map == NULL && GL(dl_profile_map) != NULL)
398 /* We must prepare the profiling. */
399 _dl_start_profile ();
401 /* Prevent unloading the object. */
402 GL(dl_profile_map)->l_flags_1 |= DF_1_NODELETE;
407 _dl_relocate_object (l, l->l_scope, reloc_mode, 0);
410 /* If the file is not loaded now as a dependency, add the search
411 list of the newly loaded object to the scope. */
412 bool any_tls = false;
413 unsigned int first_static_tls = new->l_searchlist.r_nlist;
414 for (unsigned int i = 0; i < new->l_searchlist.r_nlist; ++i)
416 struct link_map *imap = new->l_searchlist.r_list[i];
419 /* If the initializer has been called already, the object has
420 not been loaded here and now. */
421 if (imap->l_init_called && imap->l_type == lt_loaded)
423 struct r_scope_elem **runp = imap->l_scope;
426 while (*runp != NULL)
428 if (*runp == &new->l_searchlist)
435 /* Avoid duplicates. */
438 if (__builtin_expect (cnt + 1 >= imap->l_scope_max, 0))
440 /* The 'r_scope' array is too small. Allocate a new one
443 struct r_scope_elem **newp;
445 #define SCOPE_ELEMS(imap) \
446 (sizeof (imap->l_scope_mem) / sizeof (imap->l_scope_mem[0]))
448 if (imap->l_scope != imap->l_scope_mem
449 && imap->l_scope_max < SCOPE_ELEMS (imap))
451 new_size = SCOPE_ELEMS (imap);
452 newp = imap->l_scope_mem;
456 new_size = imap->l_scope_max * 2;
457 newp = (struct r_scope_elem **)
458 malloc (new_size * sizeof (struct r_scope_elem *));
460 _dl_signal_error (ENOMEM, "dlopen", NULL,
461 N_("cannot create scope list"));
464 memcpy (newp, imap->l_scope, cnt * sizeof (imap->l_scope[0]));
465 struct r_scope_elem **old = imap->l_scope;
467 imap->l_scope = newp;
469 if (old != imap->l_scope_mem)
470 _dl_scope_free (old);
472 imap->l_scope_max = new_size;
475 /* First terminate the extended list. Otherwise a thread
476 might use the new last element and then use the garbage
478 imap->l_scope[cnt + 1] = NULL;
479 atomic_write_barrier ();
480 imap->l_scope[cnt] = &new->l_searchlist;
482 /* Print only new scope information. */
485 /* Only add TLS memory if this object is loaded now and
486 therefore is not yet initialized. */
487 else if (! imap->l_init_called
488 /* Only if the module defines thread local data. */
489 && __builtin_expect (imap->l_tls_blocksize > 0, 0))
491 /* Now that we know the object is loaded successfully add
492 modules containing TLS data to the slot info table. We
493 might have to increase its size. */
494 _dl_add_to_slotinfo (imap);
496 if (imap->l_need_tls_init
497 && first_static_tls == new->l_searchlist.r_nlist)
498 first_static_tls = i;
500 /* We have to bump the generation counter. */
504 /* Print scope information. */
505 if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_SCOPES, 0))
506 _dl_show_scope (imap, from_scope);
509 /* Bump the generation number if necessary. */
510 if (any_tls && __builtin_expect (++GL(dl_tls_generation) == 0, 0))
511 _dl_fatal_printf (N_("\
512 TLS generation counter wrapped! Please report this."));
514 /* We need a second pass for static tls data, because _dl_update_slotinfo
515 must not be run while calls to _dl_add_to_slotinfo are still pending. */
516 for (unsigned int i = first_static_tls; i < new->l_searchlist.r_nlist; ++i)
518 struct link_map *imap = new->l_searchlist.r_list[i];
520 if (imap->l_need_tls_init
521 && ! imap->l_init_called
522 && imap->l_tls_blocksize > 0)
524 /* For static TLS we have to allocate the memory here and
525 now. This includes allocating memory in the DTV. But we
526 cannot change any DTV other than our own. So, if we
527 cannot guarantee that there is room in the DTV we don't
528 even try it and fail the load.
530 XXX We could track the minimum DTV slots allocated in
532 if (! RTLD_SINGLE_THREAD_P && imap->l_tls_modid > DTV_SURPLUS)
533 _dl_signal_error (0, "dlopen", NULL, N_("\
534 cannot load any more object with static TLS"));
536 imap->l_need_tls_init = 0;
538 /* Update the slot information data for at least the
539 generation of the DSO we are allocating data for. */
540 _dl_update_slotinfo (imap->l_tls_modid);
543 GL(dl_init_static_tls) (imap);
544 assert (imap->l_need_tls_init == 0);
548 /* Run the initializer functions of new objects. */
549 _dl_init (new, args->argc, args->argv, args->env);
551 /* Now we can make the new map available in the global scope. */
552 if (mode & RTLD_GLOBAL)
553 /* Move the object in the global namespace. */
554 if (add_to_global (new) != 0)
558 /* Mark the object as not deletable if the RTLD_NODELETE flags was
560 if (__builtin_expect (mode & RTLD_NODELETE, 0))
561 new->l_flags_1 |= DF_1_NODELETE;
564 /* We must be the static _dl_open in libc.a. A static program that
565 has loaded a dynamic object now has competition. */
566 __libc_multiple_libcs = 1;
569 /* Let the user know about the opencount. */
570 if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_FILES, 0))
571 _dl_debug_printf ("opening file=%s [%lu]; direct_opencount=%u\n\n",
572 new->l_name, new->l_ns, new->l_direct_opencount);
577 _dl_open (const char *file, int mode, const void *caller_dlopen, Lmid_t nsid,
578 int argc, char *argv[], char *env[])
580 if ((mode & RTLD_BINDING_MASK) == 0)
581 /* One of the flags must be set. */
582 _dl_signal_error (EINVAL, file, NULL, N_("invalid mode for dlopen()"));
584 /* Make sure we are alone. */
585 __rtld_lock_lock_recursive (GL(dl_load_lock));
587 if (__builtin_expect (nsid == LM_ID_NEWLM, 0))
589 /* Find a new namespace. */
590 for (nsid = 1; DL_NNS > 1 && nsid < GL(dl_nns); ++nsid)
591 if (GL(dl_ns)[nsid]._ns_loaded == NULL)
594 if (__builtin_expect (nsid == DL_NNS, 0))
596 /* No more namespace available. */
597 __rtld_lock_unlock_recursive (GL(dl_load_lock));
599 _dl_signal_error (EINVAL, file, NULL, N_("\
600 no more namespaces available for dlmopen()"));
602 else if (nsid == GL(dl_nns))
604 __rtld_lock_initialize (GL(dl_ns)[nsid]._ns_unique_sym_table.lock);
608 _dl_debug_initialize (0, nsid)->r_state = RT_CONSISTENT;
610 /* Never allow loading a DSO in a namespace which is empty. Such
611 direct placements is only causing problems. Also don't allow
612 loading into a namespace used for auditing. */
613 else if (__builtin_expect (nsid != LM_ID_BASE && nsid != __LM_ID_CALLER, 0)
614 && (GL(dl_ns)[nsid]._ns_nloaded == 0
615 || GL(dl_ns)[nsid]._ns_loaded->l_auditing))
616 _dl_signal_error (EINVAL, file, NULL,
617 N_("invalid target namespace in dlmopen()"));
619 else if ((nsid == LM_ID_BASE || nsid == __LM_ID_CALLER)
620 && GL(dl_ns)[LM_ID_BASE]._ns_loaded == NULL
625 struct dl_open_args args;
628 args.caller_dlopen = caller_dlopen;
629 args.caller_dl_open = RETURN_ADDRESS (0);
637 const char *errstring;
639 int errcode = _dl_catch_error (&objname, &errstring, &malloced,
640 dl_open_worker, &args);
643 /* We must munmap() the cache file. */
647 /* See if an error occurred during loading. */
648 if (__builtin_expect (errstring != NULL, 0))
650 /* Remove the object from memory. It may be in an inconsistent
651 state if relocation failed, for example. */
654 /* Maybe some of the modules which were loaded use TLS.
655 Since it will be removed in the following _dl_close call
656 we have to mark the dtv array as having gaps to fill the
657 holes. This is a pessimistic assumption which won't hurt
658 if not true. There is no need to do this when we are
659 loading the auditing DSOs since TLS has not yet been set
661 if ((mode & __RTLD_AUDIT) == 0)
662 GL(dl_tls_dtv_gaps) = true;
664 _dl_close_worker (args.map);
667 assert (_dl_debug_initialize (0, args.nsid)->r_state == RT_CONSISTENT);
669 /* Release the lock. */
670 __rtld_lock_unlock_recursive (GL(dl_load_lock));
672 /* Make a local copy of the error string so that we can release the
673 memory allocated for it. */
674 size_t len_errstring = strlen (errstring) + 1;
675 char *local_errstring;
676 if (objname == errstring + len_errstring)
678 size_t total_len = len_errstring + strlen (objname) + 1;
679 local_errstring = alloca (total_len);
680 memcpy (local_errstring, errstring, total_len);
681 objname = local_errstring + len_errstring;
685 local_errstring = alloca (len_errstring);
686 memcpy (local_errstring, errstring, len_errstring);
690 free ((char *) errstring);
692 /* Reraise the error. */
693 _dl_signal_error (errcode, objname, NULL, local_errstring);
696 assert (_dl_debug_initialize (0, args.nsid)->r_state == RT_CONSISTENT);
698 /* Release the lock. */
699 __rtld_lock_unlock_recursive (GL(dl_load_lock));
702 DL_STATIC_INIT (args.map);
710 _dl_show_scope (struct link_map *l, int from)
712 _dl_debug_printf ("object=%s [%lu]\n",
713 *l->l_name ? l->l_name : rtld_progname, l->l_ns);
714 if (l->l_scope != NULL)
715 for (int scope_cnt = from; l->l_scope[scope_cnt] != NULL; ++scope_cnt)
717 _dl_debug_printf (" scope %u:", scope_cnt);
719 for (unsigned int cnt = 0; cnt < l->l_scope[scope_cnt]->r_nlist; ++cnt)
720 if (*l->l_scope[scope_cnt]->r_list[cnt]->l_name)
721 _dl_debug_printf_c (" %s",
722 l->l_scope[scope_cnt]->r_list[cnt]->l_name);
724 _dl_debug_printf_c (" %s", rtld_progname);
726 _dl_debug_printf_c ("\n");
729 _dl_debug_printf (" no scope\n");
730 _dl_debug_printf ("\n");
734 /* Return non-zero if ADDR lies within one of L's segments. */
737 _dl_addr_inside_object (struct link_map *l, const ElfW(Addr) addr)
740 const ElfW(Addr) reladdr = addr - l->l_addr;
743 if (l->l_phdr[n].p_type == PT_LOAD
744 && reladdr - l->l_phdr[n].p_vaddr >= 0
745 && reladdr - l->l_phdr[n].p_vaddr < l->l_phdr[n].p_memsz)