1 /* Load a shared object at runtime, relocate it, and run its initializer.
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/mman.h> /* Check whether MAP_COPY is defined. */
28 #include <sys/param.h>
29 #include <bits/libc-lock.h>
36 extern ElfW(Addr) _dl_sysdep_start (void **start_argptr,
37 void (*dl_main) (const ElfW(Phdr) *phdr,
39 ElfW(Addr) *user_entry));
40 weak_extern (BP_SYM (_dl_sysdep_start))
42 /* This function is used to unload the cache file if necessary. */
43 extern void _dl_unload_cache (void);
45 extern int __libc_multiple_libcs; /* Defined in init-first.c. */
47 extern int __libc_argc;
48 extern char **__libc_argv;
50 extern char **__environ;
52 extern int _dl_lazy; /* Do we do lazy relocations? */
54 /* Undefine the following for debugging. */
55 /* #define SCOPE_DEBUG 1 */
57 static void show_scope (struct link_map *new);
60 /* During the program run we must not modify the global data of
61 loaded shared object simultanously in two threads. Therefore we
62 protect `_dl_open' and `_dl_close' in dl-close.c.
64 This must be a recursive lock since the initializer function of
65 the loaded object might as well require a call to this function.
66 At this time it is not anymore a problem to modify the tables. */
67 __libc_lock_define (extern, _dl_load_lock)
69 extern size_t _dl_platformlen;
71 /* We must be carefull not to leave us in an inconsistent state. Thus we
72 catch any error and re-raise it after cleaning up. */
83 dl_open_worker (void *a)
85 struct dl_open_args *args = a;
86 const char *file = args->file;
87 int mode = args->mode;
88 struct link_map *new, *l;
93 /* Maybe we have to expand a DST. */
94 dst = strchr (file, '$');
97 const void *caller = args->caller;
98 size_t len = strlen (file);
100 struct link_map *call_map;
103 /* DSTs must not appear in SUID/SGID programs. */
104 if (__libc_enable_secure)
105 /* This is an error. */
106 _dl_signal_error (0, "dlopen",
107 N_("DST not allowed in SUID/SGID programs"));
109 /* We have to find out from which object the caller is calling.
110 Find the highest-addressed object that ADDRESS is not below. */
112 for (l = _dl_loaded; l; l = l->l_next)
113 if (l->l_addr != 0 /* Make sure we do not currently set this map up
115 && caller >= (const void *) l->l_map_start
116 && caller < (const void *) l->l_map_end)
118 /* There must be exactly one DSO for the range of the virtual
119 memory. Otherwise something is really broken. */
124 if (call_map == NULL)
125 /* In this case we assume this is the main application. */
126 call_map = _dl_loaded;
128 /* Determine how much space we need. We have to allocate the
130 required = DL_DST_REQUIRED (call_map, file, len, _dl_dst_count (dst, 0));
132 /* Get space for the new file name. */
133 new_file = (char *) alloca (required + 1);
135 /* Generate the new file name. */
136 DL_DST_SUBSTITUTE (call_map, file, new_file, 0);
138 /* If the substitution failed don't try to load. */
139 if (*new_file == '\0')
140 _dl_signal_error (0, "dlopen",
141 N_("empty dynamic string token substitution"));
143 /* Now we have a new file name. */
147 /* Load the named object. */
148 args->map = new = _dl_map_object (NULL, file, 0, lt_loaded, 0,
151 /* If the pointer returned is NULL this means the RTLD_NOLOAD flag is
152 set and the object is not already loaded. */
155 assert (mode & RTLD_NOLOAD);
159 if (new->l_searchlist.r_list)
160 /* It was already open. */
163 /* Load that object's dependencies. */
164 _dl_map_object_deps (new, NULL, 0, 0);
166 /* So far, so good. Now check the versions. */
167 for (i = 0; i < new->l_searchlist.r_nlist; ++i)
168 if (new->l_searchlist.r_list[i]->l_versions == NULL)
169 (void) _dl_check_map_versions (new->l_searchlist.r_list[i], 0, 0);
175 /* Only do lazy relocation if `LD_BIND_NOW' is not set. */
176 lazy = (mode & RTLD_BINDING_MASK) == RTLD_LAZY && _dl_lazy;
178 /* Relocate the objects loaded. We do this in reverse order so that copy
179 relocs of earlier objects overwrite the data written by later objects. */
186 if (! l->l_relocated)
189 if (_dl_profile != NULL)
191 /* If this here is the shared object which we want to profile
192 make sure the profile is started. We can find out whether
193 this is necessary or not by observing the `_dl_profile_map'
194 variable. If was NULL but is not NULL afterwars we must
195 start the profiling. */
196 struct link_map *old_profile_map = _dl_profile_map;
198 _dl_relocate_object (l, l->l_scope, 1, 1);
200 if (old_profile_map == NULL && _dl_profile_map != NULL)
201 /* We must prepare the profiling. */
202 _dl_start_profile (_dl_profile_map, _dl_profile_output);
206 _dl_relocate_object (l, l->l_scope, lazy, 0);
214 /* Run the initializer functions of new objects. */
215 _dl_init (new, __libc_argc, __libc_argv, __environ);
217 /* Now we can make the new map available in the global scope. */
218 if (mode & RTLD_GLOBAL)
220 struct link_map **new_global;
221 unsigned int to_add = 0;
224 /* Count the objects we have to put in the global scope. */
225 for (cnt = 0; cnt < new->l_searchlist.r_nlist; ++cnt)
226 if (new->l_searchlist.r_list[cnt]->l_global == 0)
229 /* The symbols of the new objects and its dependencies are to be
230 introduced into the global scope that will be used to resolve
231 references from other dynamically-loaded objects.
233 The global scope is the searchlist in the main link map. We
234 extend this list if necessary. There is one problem though:
235 since this structure was allocated very early (before the libc
236 is loaded) the memory it uses is allocated by the malloc()-stub
237 in the ld.so. When we come here these functions are not used
238 anymore. Instead the malloc() implementation of the libc is
239 used. But this means the block from the main map cannot be used
240 in an realloc() call. Therefore we allocate a completely new
241 array the first time we have to add something to the locale scope. */
243 if (_dl_global_scope_alloc == 0)
245 /* This is the first dynamic object given global scope. */
246 _dl_global_scope_alloc = _dl_main_searchlist->r_nlist + to_add + 8;
247 new_global = (struct link_map **)
248 malloc (_dl_global_scope_alloc * sizeof (struct link_map *));
249 if (new_global == NULL)
251 _dl_global_scope_alloc = 0;
253 _dl_signal_error (ENOMEM, new->l_libname->name,
254 N_("cannot extend global scope"));
258 /* Copy over the old entries. */
259 memcpy (new_global, _dl_main_searchlist->r_list,
260 (_dl_main_searchlist->r_nlist * sizeof (struct link_map *)));
262 _dl_main_searchlist->r_list = new_global;
264 else if (_dl_main_searchlist->r_nlist + to_add > _dl_global_scope_alloc)
266 /* We have to extend the existing array of link maps in the
268 new_global = (struct link_map **)
269 realloc (_dl_main_searchlist->r_list,
270 ((_dl_global_scope_alloc + to_add + 8)
271 * sizeof (struct link_map *)));
272 if (new_global == NULL)
275 _dl_global_scope_alloc += to_add + 8;
276 _dl_main_searchlist->r_list = new_global;
279 /* Now add the new entries. */
280 for (cnt = 0; cnt < new->l_searchlist.r_nlist; ++cnt)
282 struct link_map *map = new->l_searchlist.r_list[cnt];
284 if (map->l_global == 0)
287 _dl_main_searchlist->r_list[_dl_main_searchlist->r_nlist] = map;
288 ++_dl_main_searchlist->r_nlist;
292 /* XXX Do we have to add something to r_dupsearchlist??? --drepper */
295 /* Mark the object as not deletable if the RTLD_NODELETE flags was
297 if (__builtin_expect (mode & RTLD_NODELETE, 0))
298 new->l_flags_1 |= DF_1_NODELETE;
300 if (_dl_sysdep_start == NULL)
301 /* We must be the static _dl_open in libc.a. A static program that
302 has loaded a dynamic object now has competition. */
303 __libc_multiple_libcs = 1;
309 _dl_open (const char *file, int mode, const void *caller)
311 struct dl_open_args args;
313 const char *errstring;
316 if ((mode & RTLD_BINDING_MASK) == 0)
317 /* One of the flags must be set. */
318 _dl_signal_error (EINVAL, file, N_("invalid mode for dlopen()"));
320 /* Make sure we are alone. */
321 __libc_lock_lock (_dl_load_lock);
325 args.caller = caller;
327 errcode = _dl_catch_error (&objname, &errstring, dl_open_worker, &args);
330 /* We must munmap() the cache file. */
334 /* Release the lock. */
335 __libc_lock_unlock (_dl_load_lock);
339 /* Some error occurred during loading. */
340 char *local_errstring;
342 /* Remove the object from memory. It may be in an inconsistent
343 state if relocation failed, for example. */
345 _dl_close (args.map);
347 /* Make a local copy of the error string so that we can release the
348 memory allocated for it. */
349 local_errstring = strdupa (errstring);
350 if (errstring != _dl_out_of_memory)
351 free ((char *) errstring);
353 /* Reraise the error. */
354 _dl_signal_error (errcode, objname, local_errstring);
365 show_scope (struct link_map *new)
369 for (scope_cnt = 0; new->l_scope[scope_cnt] != NULL; ++scope_cnt)
374 numbuf[0] = '0' + scope_cnt;
376 _dl_sysdep_message ("scope ", numbuf, ":", NULL);
378 for (cnt = 0; cnt < new->l_scope[scope_cnt]->r_nlist; ++cnt)
379 if (*new->l_scope[scope_cnt]->r_list[cnt]->l_name)
380 _dl_sysdep_message (" ",
381 new->l_scope[scope_cnt]->r_list[cnt]->l_name,
384 _dl_sysdep_message (" <main>", NULL);
386 _dl_sysdep_message ("\n", NULL);