* sysdeps/unix/sysv/linux/sys/signalfd.h (signalfd): Fix __THROW vs.
[glibc.git] / elf / dl-open.c
blobf825aa0437fa8175af1b7e3dff6a6771b21cdd65
1 /* Load a shared object at runtime, relocate it, and run its initializer.
2 Copyright (C) 1996-2004, 2005, 2006, 2007 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
18 02111-1307 USA. */
20 #include <assert.h>
21 #include <dlfcn.h>
22 #include <errno.h>
23 #include <libintl.h>
24 #include <stdio.h>
25 #include <stdlib.h>
26 #include <string.h>
27 #include <unistd.h>
28 #include <sys/mman.h> /* Check whether MAP_COPY is defined. */
29 #include <sys/param.h>
30 #include <bits/libc-lock.h>
31 #include <ldsodefs.h>
32 #include <bp-sym.h>
33 #include <caller.h>
34 #include <sysdep-cancel.h>
35 #include <tls.h>
37 #include <dl-dst.h>
40 extern ElfW(Addr) _dl_sysdep_start (void **start_argptr,
41 void (*dl_main) (const ElfW(Phdr) *phdr,
42 ElfW(Word) phnum,
43 ElfW(Addr) *user_entry));
44 weak_extern (BP_SYM (_dl_sysdep_start))
46 extern int __libc_multiple_libcs; /* Defined in init-first.c. */
48 /* Undefine the following for debugging. */
49 /* #define SCOPE_DEBUG 1 */
50 #ifdef SCOPE_DEBUG
51 static void show_scope (struct link_map *new);
52 #endif
54 /* We must be carefull not to leave us in an inconsistent state. Thus we
55 catch any error and re-raise it after cleaning up. */
57 struct dl_open_args
59 const char *file;
60 int mode;
61 /* This is the caller of the dlopen() function. */
62 const void *caller_dlopen;
63 /* This is the caller if _dl_open(). */
64 const void *caller_dl_open;
65 struct link_map *map;
66 /* Namespace ID. */
67 Lmid_t nsid;
68 /* Original parameters to the program and the current environment. */
69 int argc;
70 char **argv;
71 char **env;
75 static int
76 add_to_global (struct link_map *new)
78 struct link_map **new_global;
79 unsigned int to_add = 0;
80 unsigned int cnt;
82 /* Count the objects we have to put in the global scope. */
83 for (cnt = 0; cnt < new->l_searchlist.r_nlist; ++cnt)
84 if (new->l_searchlist.r_list[cnt]->l_global == 0)
85 ++to_add;
87 /* The symbols of the new objects and its dependencies are to be
88 introduced into the global scope that will be used to resolve
89 references from other dynamically-loaded objects.
91 The global scope is the searchlist in the main link map. We
92 extend this list if necessary. There is one problem though:
93 since this structure was allocated very early (before the libc
94 is loaded) the memory it uses is allocated by the malloc()-stub
95 in the ld.so. When we come here these functions are not used
96 anymore. Instead the malloc() implementation of the libc is
97 used. But this means the block from the main map cannot be used
98 in an realloc() call. Therefore we allocate a completely new
99 array the first time we have to add something to the locale scope. */
101 struct link_namespaces *ns = &GL(dl_ns)[new->l_ns];
102 if (ns->_ns_global_scope_alloc == 0)
104 /* This is the first dynamic object given global scope. */
105 ns->_ns_global_scope_alloc
106 = ns->_ns_main_searchlist->r_nlist + to_add + 8;
107 new_global = (struct link_map **)
108 malloc (ns->_ns_global_scope_alloc * sizeof (struct link_map *));
109 if (new_global == NULL)
111 ns->_ns_global_scope_alloc = 0;
112 nomem:
113 _dl_signal_error (ENOMEM, new->l_libname->name, NULL,
114 N_("cannot extend global scope"));
115 return 1;
118 /* Copy over the old entries. */
119 ns->_ns_main_searchlist->r_list
120 = memcpy (new_global, ns->_ns_main_searchlist->r_list,
121 (ns->_ns_main_searchlist->r_nlist
122 * sizeof (struct link_map *)));
124 else if (ns->_ns_main_searchlist->r_nlist + to_add
125 > ns->_ns_global_scope_alloc)
127 /* We have to extend the existing array of link maps in the
128 main map. */
129 struct link_map **old_global
130 = GL(dl_ns)[new->l_ns]._ns_main_searchlist->r_list;
131 size_t new_nalloc = ((ns->_ns_global_scope_alloc + to_add) * 2);
133 new_global = (struct link_map **)
134 malloc (new_nalloc * sizeof (struct link_map *));
135 if (new_global == NULL)
136 goto nomem;
138 memcpy (new_global, old_global,
139 ns->_ns_global_scope_alloc * sizeof (struct link_map *));
141 ns->_ns_global_scope_alloc = new_nalloc;
142 ns->_ns_main_searchlist->r_list = new_global;
144 if (!RTLD_SINGLE_THREAD_P)
145 THREAD_GSCOPE_WAIT ();
147 free (old_global);
150 /* Now add the new entries. */
151 unsigned int new_nlist = ns->_ns_main_searchlist->r_nlist;
152 for (cnt = 0; cnt < new->l_searchlist.r_nlist; ++cnt)
154 struct link_map *map = new->l_searchlist.r_list[cnt];
156 if (map->l_global == 0)
158 map->l_global = 1;
159 ns->_ns_main_searchlist->r_list[new_nlist++] = map;
162 atomic_write_barrier ();
163 ns->_ns_main_searchlist->r_nlist = new_nlist;
165 return 0;
169 _dl_scope_free (void *old)
171 struct dl_scope_free_list *fsl;
172 #define DL_SCOPE_FREE_LIST_SIZE (sizeof (fsl->list) / sizeof (fsl->list[0]))
174 if (RTLD_SINGLE_THREAD_P)
175 free (old);
176 else if ((fsl = GL(dl_scope_free_list)) == NULL)
178 GL(dl_scope_free_list) = fsl = malloc (sizeof (*fsl));
179 if (fsl == NULL)
181 THREAD_GSCOPE_WAIT ();
182 free (old);
183 return 1;
185 else
187 fsl->list[0] = old;
188 fsl->count = 1;
191 else if (fsl->count < DL_SCOPE_FREE_LIST_SIZE)
192 fsl->list[fsl->count++] = old;
193 else
195 THREAD_GSCOPE_WAIT ();
196 while (fsl->count > 0)
197 free (fsl->list[--fsl->count]);
198 return 1;
200 return 0;
203 static void
204 dl_open_worker (void *a)
206 struct dl_open_args *args = a;
207 const char *file = args->file;
208 int mode = args->mode;
209 struct link_map *new;
210 int lazy;
211 unsigned int i;
212 bool any_tls = false;
213 struct link_map *call_map = NULL;
215 /* Check whether _dl_open() has been called from a valid DSO. */
216 if (__check_caller (args->caller_dl_open,
217 allow_libc|allow_libdl|allow_ldso) != 0)
218 _dl_signal_error (0, "dlopen", NULL, N_("invalid caller"));
220 /* Determine the caller's map if necessary. This is needed in case
221 we have a DST, when we don't know the namespace ID we have to put
222 the new object in, or when the file name has no path in which
223 case we need to look along the RUNPATH/RPATH of the caller. */
224 const char *dst = strchr (file, '$');
225 if (dst != NULL || args->nsid == __LM_ID_CALLER
226 || strchr (file, '/') == NULL)
228 const void *caller_dlopen = args->caller_dlopen;
230 /* We have to find out from which object the caller is calling.
231 By default we assume this is the main application. */
232 call_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
234 struct link_map *l;
235 for (Lmid_t ns = 0; ns < DL_NNS; ++ns)
236 for (l = GL(dl_ns)[ns]._ns_loaded; l != NULL; l = l->l_next)
237 if (caller_dlopen >= (const void *) l->l_map_start
238 && caller_dlopen < (const void *) l->l_map_end
239 && (l->l_contiguous
240 || _dl_addr_inside_object (l, (ElfW(Addr)) caller_dlopen)))
242 assert (ns == l->l_ns);
243 call_map = l;
244 goto found_caller;
247 found_caller:
248 if (args->nsid == __LM_ID_CALLER)
250 #ifndef SHARED
251 /* In statically linked apps there might be no loaded object. */
252 if (call_map == NULL)
253 args->nsid = LM_ID_BASE;
254 else
255 #endif
256 args->nsid = call_map->l_ns;
260 assert (_dl_debug_initialize (0, args->nsid)->r_state == RT_CONSISTENT);
262 /* Maybe we have to expand a DST. */
263 if (__builtin_expect (dst != NULL, 0))
265 size_t len = strlen (file);
266 size_t required;
267 char *new_file;
269 /* Determine how much space we need. We have to allocate the
270 memory locally. */
271 required = DL_DST_REQUIRED (call_map, file, len, _dl_dst_count (dst, 0));
273 /* Get space for the new file name. */
274 new_file = (char *) alloca (required + 1);
276 /* Generate the new file name. */
277 _dl_dst_substitute (call_map, file, new_file, 0);
279 /* If the substitution failed don't try to load. */
280 if (*new_file == '\0')
281 _dl_signal_error (0, "dlopen", NULL,
282 N_("empty dynamic string token substitution"));
284 /* Now we have a new file name. */
285 file = new_file;
287 /* It does not matter whether call_map is set even if we
288 computed it only because of the DST. Since the path contains
289 a slash the value is not used. See dl-load.c. */
292 /* Load the named object. */
293 args->map = new = _dl_map_object (call_map, file, 0, lt_loaded, 0,
294 mode | __RTLD_CALLMAP, args->nsid);
296 /* If the pointer returned is NULL this means the RTLD_NOLOAD flag is
297 set and the object is not already loaded. */
298 if (new == NULL)
300 assert (mode & RTLD_NOLOAD);
301 return;
304 if (__builtin_expect (mode & __RTLD_SPROF, 0))
305 /* This happens only if we load a DSO for 'sprof'. */
306 return;
308 /* This object is directly loaded. */
309 ++new->l_direct_opencount;
311 /* It was already open. */
312 if (__builtin_expect (new->l_searchlist.r_list != NULL, 0))
314 /* Let the user know about the opencount. */
315 if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_FILES, 0))
316 _dl_debug_printf ("opening file=%s [%lu]; direct_opencount=%u\n\n",
317 new->l_name, new->l_ns, new->l_direct_opencount);
319 /* If the user requested the object to be in the global namespace
320 but it is not so far, add it now. */
321 if ((mode & RTLD_GLOBAL) && new->l_global == 0)
322 (void) add_to_global (new);
324 assert (_dl_debug_initialize (0, args->nsid)->r_state == RT_CONSISTENT);
326 return;
329 /* Load that object's dependencies. */
330 _dl_map_object_deps (new, NULL, 0, 0,
331 mode & (__RTLD_DLOPEN | RTLD_DEEPBIND | __RTLD_AUDIT));
333 /* So far, so good. Now check the versions. */
334 for (i = 0; i < new->l_searchlist.r_nlist; ++i)
335 if (new->l_searchlist.r_list[i]->l_real->l_versions == NULL)
336 (void) _dl_check_map_versions (new->l_searchlist.r_list[i]->l_real,
337 0, 0);
339 #ifdef SCOPE_DEBUG
340 show_scope (new);
341 #endif
343 #ifdef SHARED
344 /* Auditing checkpoint: we have added all objects. */
345 if (__builtin_expect (GLRO(dl_naudit) > 0, 0))
347 struct link_map *head = GL(dl_ns)[new->l_ns]._ns_loaded;
348 /* Do not call the functions for any auditing object. */
349 if (head->l_auditing == 0)
351 struct audit_ifaces *afct = GLRO(dl_audit);
352 for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
354 if (afct->activity != NULL)
355 afct->activity (&head->l_audit[cnt].cookie, LA_ACT_CONSISTENT);
357 afct = afct->next;
361 #endif
363 /* Notify the debugger all new objects are now ready to go. */
364 struct r_debug *r = _dl_debug_initialize (0, args->nsid);
365 r->r_state = RT_CONSISTENT;
366 _dl_debug_state ();
368 /* Only do lazy relocation if `LD_BIND_NOW' is not set. */
369 lazy = (mode & RTLD_BINDING_MASK) == RTLD_LAZY && GLRO(dl_lazy);
371 /* Relocate the objects loaded. We do this in reverse order so that copy
372 relocs of earlier objects overwrite the data written by later objects. */
374 struct link_map *l = new;
375 while (l->l_next)
376 l = l->l_next;
377 while (1)
379 if (! l->l_real->l_relocated)
381 #ifdef SHARED
382 if (__builtin_expect (GLRO(dl_profile) != NULL, 0))
384 /* If this here is the shared object which we want to profile
385 make sure the profile is started. We can find out whether
386 this is necessary or not by observing the `_dl_profile_map'
387 variable. If was NULL but is not NULL afterwars we must
388 start the profiling. */
389 struct link_map *old_profile_map = GL(dl_profile_map);
391 _dl_relocate_object (l, l->l_scope, 1, 1);
393 if (old_profile_map == NULL && GL(dl_profile_map) != NULL)
395 /* We must prepare the profiling. */
396 _dl_start_profile ();
398 /* Prevent unloading the object. */
399 GL(dl_profile_map)->l_flags_1 |= DF_1_NODELETE;
402 else
403 #endif
404 _dl_relocate_object (l, l->l_scope, lazy, 0);
407 if (l == new)
408 break;
409 l = l->l_prev;
412 /* If the file is not loaded now as a dependency, add the search
413 list of the newly loaded object to the scope. */
414 for (i = 0; i < new->l_searchlist.r_nlist; ++i)
416 struct link_map *imap = new->l_searchlist.r_list[i];
418 /* If the initializer has been called already, the object has
419 not been loaded here and now. */
420 if (imap->l_init_called && imap->l_type == lt_loaded)
422 struct r_scope_elem **runp = imap->l_scope;
423 size_t cnt = 0;
425 while (*runp != NULL)
427 if (*runp == &new->l_searchlist)
428 break;
429 ++cnt;
430 ++runp;
433 if (*runp != NULL)
434 /* Avoid duplicates. */
435 continue;
437 if (__builtin_expect (cnt + 1 >= imap->l_scope_max, 0))
439 /* The 'r_scope' array is too small. Allocate a new one
440 dynamically. */
441 size_t new_size;
442 struct r_scope_elem **newp;
444 #define SCOPE_ELEMS(imap) \
445 (sizeof (imap->l_scope_mem) / sizeof (imap->l_scope_mem[0]))
447 if (imap->l_scope != imap->l_scope_mem
448 && imap->l_scope_max < SCOPE_ELEMS (imap))
450 new_size = SCOPE_ELEMS (imap);
451 newp = imap->l_scope_mem;
453 else
455 new_size = imap->l_scope_max * 2;
456 newp = (struct r_scope_elem **)
457 malloc (new_size * sizeof (struct r_scope_elem *));
458 if (newp == NULL)
459 _dl_signal_error (ENOMEM, "dlopen", NULL,
460 N_("cannot create scope list"));
463 memcpy (newp, imap->l_scope, cnt * sizeof (imap->l_scope[0]));
464 struct r_scope_elem **old = imap->l_scope;
466 imap->l_scope = newp;
468 if (old != imap->l_scope_mem)
469 _dl_scope_free (old);
471 imap->l_scope_max = new_size;
474 /* First terminate the extended list. Otherwise a thread
475 might use the new last element and then use the garbage
476 at offset IDX+1. */
477 imap->l_scope[cnt + 1] = NULL;
478 atomic_write_barrier ();
479 imap->l_scope[cnt] = &new->l_searchlist;
481 /* Only add TLS memory if this object is loaded now and
482 therefore is not yet initialized. */
483 else if (! imap->l_init_called
484 /* Only if the module defines thread local data. */
485 && __builtin_expect (imap->l_tls_blocksize > 0, 0))
487 /* Now that we know the object is loaded successfully add
488 modules containing TLS data to the slot info table. We
489 might have to increase its size. */
490 _dl_add_to_slotinfo (imap);
492 if (imap->l_need_tls_init)
494 imap->l_need_tls_init = 0;
495 #ifdef SHARED
496 /* Update the slot information data for at least the
497 generation of the DSO we are allocating data for. */
498 _dl_update_slotinfo (imap->l_tls_modid);
499 #endif
501 GL(dl_init_static_tls) (imap);
502 assert (imap->l_need_tls_init == 0);
505 /* We have to bump the generation counter. */
506 any_tls = true;
510 /* Bump the generation number if necessary. */
511 if (any_tls && __builtin_expect (++GL(dl_tls_generation) == 0, 0))
512 _dl_fatal_printf (N_("\
513 TLS generation counter wrapped! Please report this."));
515 /* Run the initializer functions of new objects. */
516 _dl_init (new, args->argc, args->argv, args->env);
518 /* Now we can make the new map available in the global scope. */
519 if (mode & RTLD_GLOBAL)
520 /* Move the object in the global namespace. */
521 if (add_to_global (new) != 0)
522 /* It failed. */
523 return;
525 /* Mark the object as not deletable if the RTLD_NODELETE flags was
526 passed. */
527 if (__builtin_expect (mode & RTLD_NODELETE, 0))
528 new->l_flags_1 |= DF_1_NODELETE;
530 #ifndef SHARED
531 /* We must be the static _dl_open in libc.a. A static program that
532 has loaded a dynamic object now has competition. */
533 __libc_multiple_libcs = 1;
534 #endif
536 /* Let the user know about the opencount. */
537 if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_FILES, 0))
538 _dl_debug_printf ("opening file=%s [%lu]; direct_opencount=%u\n\n",
539 new->l_name, new->l_ns, new->l_direct_opencount);
543 void *
544 _dl_open (const char *file, int mode, const void *caller_dlopen, Lmid_t nsid,
545 int argc, char *argv[], char *env[])
547 if ((mode & RTLD_BINDING_MASK) == 0)
548 /* One of the flags must be set. */
549 _dl_signal_error (EINVAL, file, NULL, N_("invalid mode for dlopen()"));
551 /* Make sure we are alone. */
552 __rtld_lock_lock_recursive (GL(dl_load_lock));
554 if (nsid == LM_ID_NEWLM)
556 /* Find a new namespace. */
557 for (nsid = 1; nsid < DL_NNS; ++nsid)
558 if (GL(dl_ns)[nsid]._ns_loaded == NULL)
559 break;
561 if (nsid == DL_NNS)
563 /* No more namespace available. */
564 __rtld_lock_unlock_recursive (GL(dl_load_lock));
566 _dl_signal_error (EINVAL, file, NULL, N_("\
567 no more namespaces available for dlmopen()"));
570 _dl_debug_initialize (0, nsid)->r_state = RT_CONSISTENT;
572 /* Never allow loading a DSO in a namespace which is empty. Such
573 direct placements is only causing problems. Also don't allow
574 loading into a namespace used for auditing. */
575 else if (nsid != LM_ID_BASE && nsid != __LM_ID_CALLER
576 && (GL(dl_ns)[nsid]._ns_nloaded == 0
577 || GL(dl_ns)[nsid]._ns_loaded->l_auditing))
578 _dl_signal_error (EINVAL, file, NULL,
579 N_("invalid target namespace in dlmopen()"));
581 struct dl_open_args args;
582 args.file = file;
583 args.mode = mode;
584 args.caller_dlopen = caller_dlopen;
585 args.caller_dl_open = RETURN_ADDRESS (0);
586 args.map = NULL;
587 args.nsid = nsid;
588 args.argc = argc;
589 args.argv = argv;
590 args.env = env;
592 const char *objname;
593 const char *errstring;
594 bool malloced;
595 int errcode = _dl_catch_error (&objname, &errstring, &malloced,
596 dl_open_worker, &args);
598 #ifndef MAP_COPY
599 /* We must munmap() the cache file. */
600 _dl_unload_cache ();
601 #endif
603 /* See if an error occurred during loading. */
604 if (__builtin_expect (errstring != NULL, 0))
606 /* Remove the object from memory. It may be in an inconsistent
607 state if relocation failed, for example. */
608 if (args.map)
610 /* Maybe some of the modules which were loaded use TLS.
611 Since it will be removed in the following _dl_close call
612 we have to mark the dtv array as having gaps to fill the
613 holes. This is a pessimistic assumption which won't hurt
614 if not true. There is no need to do this when we are
615 loading the auditing DSOs since TLS has not yet been set
616 up. */
617 if ((mode & __RTLD_AUDIT) == 0)
618 GL(dl_tls_dtv_gaps) = true;
620 _dl_close_worker (args.map);
623 assert (_dl_debug_initialize (0, args.nsid)->r_state == RT_CONSISTENT);
625 /* Release the lock. */
626 __rtld_lock_unlock_recursive (GL(dl_load_lock));
628 /* Make a local copy of the error string so that we can release the
629 memory allocated for it. */
630 size_t len_errstring = strlen (errstring) + 1;
631 char *local_errstring;
632 if (objname == errstring + len_errstring)
634 size_t total_len = len_errstring + strlen (objname) + 1;
635 local_errstring = alloca (total_len);
636 memcpy (local_errstring, errstring, total_len);
637 objname = local_errstring + len_errstring;
639 else
641 local_errstring = alloca (len_errstring);
642 memcpy (local_errstring, errstring, len_errstring);
645 if (malloced)
646 free ((char *) errstring);
648 /* Reraise the error. */
649 _dl_signal_error (errcode, objname, NULL, local_errstring);
652 assert (_dl_debug_initialize (0, args.nsid)->r_state == RT_CONSISTENT);
654 /* Release the lock. */
655 __rtld_lock_unlock_recursive (GL(dl_load_lock));
657 #ifndef SHARED
658 DL_STATIC_INIT (args.map);
659 #endif
661 return args.map;
665 #ifdef SCOPE_DEBUG
666 #include <unistd.h>
668 static void
669 show_scope (struct link_map *new)
671 int scope_cnt;
673 for (scope_cnt = 0; new->l_scope[scope_cnt] != NULL; ++scope_cnt)
675 char numbuf[2];
676 unsigned int cnt;
678 numbuf[0] = '0' + scope_cnt;
679 numbuf[1] = '\0';
680 _dl_printf ("scope %s:", numbuf);
682 for (cnt = 0; cnt < new->l_scope[scope_cnt]->r_nlist; ++cnt)
683 if (*new->l_scope[scope_cnt]->r_list[cnt]->l_name)
684 _dl_printf (" %s", new->l_scope[scope_cnt]->r_list[cnt]->l_name);
685 else
686 _dl_printf (" <main>");
688 _dl_printf ("\n");
691 #endif
693 #ifdef IS_IN_rtld
694 /* Return non-zero if ADDR lies within one of L's segments. */
696 internal_function
697 _dl_addr_inside_object (struct link_map *l, const ElfW(Addr) addr)
699 int n = l->l_phnum;
700 const ElfW(Addr) reladdr = addr - l->l_addr;
702 while (--n >= 0)
703 if (l->l_phdr[n].p_type == PT_LOAD
704 && reladdr - l->l_phdr[n].p_vaddr >= 0
705 && reladdr - l->l_phdr[n].p_vaddr < l->l_phdr[n].p_memsz)
706 return 1;
707 return 0;
709 #endif