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;
92 /* Maybe we have to expand a DST. */
93 dst = strchr (file, '$');
96 const void *caller = args->caller;
97 size_t len = strlen (file);
99 struct link_map *call_map;
102 /* DSTs must not appear in SUID/SGID programs. */
103 if (__libc_enable_secure)
104 /* This is an error. */
105 _dl_signal_error (0, "dlopen",
106 N_("DST not allowed in SUID/SGID programs"));
108 /* We have to find out from which object the caller is calling.
109 Find the highest-addressed object that ADDRESS is not below. */
111 for (l = _dl_loaded; l; l = l->l_next)
112 if (l->l_addr != 0 /* Make sure we do not currently set this map up
114 && caller >= (const void *) l->l_map_start
115 && caller < (const void *) l->l_map_end)
117 /* There must be exactly one DSO for the range of the virtual
118 memory. Otherwise something is really broken. */
123 if (call_map == NULL)
124 /* In this case we assume this is the main application. */
125 call_map = _dl_loaded;
127 /* Determine how much space we need. We have to allocate the
129 required = DL_DST_REQUIRED (call_map, file, len, _dl_dst_count (dst, 0));
131 /* Get space for the new file name. */
132 new_file = (char *) alloca (required + 1);
134 /* Generate the new file name. */
135 DL_DST_SUBSTITUTE (call_map, file, new_file, 0);
137 /* If the substitution failed don't try to load. */
138 if (*new_file == '\0')
139 _dl_signal_error (0, "dlopen",
140 N_("empty dynamic string token substitution"));
142 /* Now we have a new file name. */
146 /* Load the named object. */
147 args->map = new = _dl_map_object (NULL, file, 0, lt_loaded, 0);
148 if (new->l_searchlist.r_list)
149 /* It was already open. */
152 /* Load that object's dependencies. */
153 _dl_map_object_deps (new, NULL, 0, 0);
155 /* So far, so good. Now check the versions. */
156 (void) _dl_check_all_versions (new, 0, 0);
162 /* Only do lazy relocation if `LD_BIND_NOW' is not set. */
163 lazy = (mode & RTLD_BINDING_MASK) == RTLD_LAZY && _dl_lazy;
165 /* Relocate the objects loaded. We do this in reverse order so that copy
166 relocs of earlier objects overwrite the data written by later objects. */
173 if (! l->l_relocated)
176 if (_dl_profile != NULL)
178 /* If this here is the shared object which we want to profile
179 make sure the profile is started. We can find out whether
180 this is necessary or not by observing the `_dl_profile_map'
181 variable. If was NULL but is not NULL afterwars we must
182 start the profiling. */
183 struct link_map *old_profile_map = _dl_profile_map;
185 _dl_relocate_object (l, l->l_scope, 1, 1);
187 if (old_profile_map == NULL && _dl_profile_map != NULL)
188 /* We must prepare the profiling. */
189 _dl_start_profile (_dl_profile_map, _dl_profile_output);
193 _dl_relocate_object (l, l->l_scope, lazy, 0);
201 /* Run the initializer functions of new objects. */
202 _dl_init (new, __libc_argc, __libc_argv, __environ);
204 /* Now we can make the new map available in the global scope. */
205 if (mode & RTLD_GLOBAL)
207 struct link_map **new_global;
208 unsigned int to_add = 0;
211 /* Count the objects we have to put in the global scope. */
212 for (cnt = 0; cnt < new->l_searchlist.r_nlist; ++cnt)
213 if (new->l_searchlist.r_list[cnt]->l_global == 0)
216 /* The symbols of the new objects and its dependencies are to be
217 introduced into the global scope that will be used to resolve
218 references from other dynamically-loaded objects.
220 The global scope is the searchlist in the main link map. We
221 extend this list if necessary. There is one problem though:
222 since this structure was allocated very early (before the libc
223 is loaded) the memory it uses is allocated by the malloc()-stub
224 in the ld.so. When we come here these functions are not used
225 anymore. Instead the malloc() implementation of the libc is
226 used. But this means the block from the main map cannot be used
227 in an realloc() call. Therefore we allocate a completely new
228 array the first time we have to add something to the locale scope. */
230 if (_dl_global_scope_alloc == 0)
232 /* This is the first dynamic object given global scope. */
233 _dl_global_scope_alloc = _dl_main_searchlist->r_nlist + to_add + 8;
234 new_global = (struct link_map **)
235 malloc (_dl_global_scope_alloc * sizeof (struct link_map *));
236 if (new_global == NULL)
238 _dl_global_scope_alloc = 0;
240 _dl_signal_error (ENOMEM, new->l_libname->name,
241 N_("cannot extend global scope"));
245 /* Copy over the old entries. */
246 memcpy (new_global, _dl_main_searchlist->r_list,
247 (_dl_main_searchlist->r_nlist * sizeof (struct link_map *)));
249 _dl_main_searchlist->r_list = new_global;
251 else if (_dl_main_searchlist->r_nlist + to_add > _dl_global_scope_alloc)
253 /* We have to extend the existing array of link maps in the
255 new_global = (struct link_map **)
256 realloc (_dl_main_searchlist->r_list,
257 ((_dl_global_scope_alloc + to_add + 8)
258 * sizeof (struct link_map *)));
259 if (new_global == NULL)
262 _dl_global_scope_alloc += to_add + 8;
263 _dl_main_searchlist->r_list = new_global;
266 /* Now add the new entries. */
267 for (cnt = 0; cnt < new->l_searchlist.r_nlist; ++cnt)
269 struct link_map *map = new->l_searchlist.r_list[cnt];
271 if (map->l_global == 0)
274 _dl_main_searchlist->r_list[_dl_main_searchlist->r_nlist] = map;
275 ++_dl_main_searchlist->r_nlist;
279 /* XXX Do we have to add something to r_dupsearchlist??? --drepper */
282 if (_dl_sysdep_start == NULL)
283 /* We must be the static _dl_open in libc.a. A static program that
284 has loaded a dynamic object now has competition. */
285 __libc_multiple_libcs = 1;
291 _dl_open (const char *file, int mode, const void *caller)
293 struct dl_open_args args;
295 const char *errstring;
298 if ((mode & RTLD_BINDING_MASK) == 0)
299 /* One of the flags must be set. */
300 _dl_signal_error (EINVAL, file, N_("invalid mode for dlopen()"));
302 /* Make sure we are alone. */
303 __libc_lock_lock (_dl_load_lock);
307 args.caller = caller;
309 errcode = _dl_catch_error (&objname, &errstring, dl_open_worker, &args);
312 /* We must munmap() the cache file. */
316 /* Release the lock. */
317 __libc_lock_unlock (_dl_load_lock);
321 /* Some error occurred during loading. */
322 char *local_errstring;
324 /* Remove the object from memory. It may be in an inconsistent
325 state if relocation failed, for example. */
327 _dl_close (args.map);
329 /* Make a local copy of the error string so that we can release the
330 memory allocated for it. */
331 local_errstring = strdupa (errstring);
332 free ((char *) errstring);
334 /* Reraise the error. */
335 _dl_signal_error (errcode, objname, local_errstring);
346 show_scope (struct link_map *new)
350 for (scope_cnt = 0; new->l_scope[scope_cnt] != NULL; ++scope_cnt)
355 numbuf[0] = '0' + scope_cnt;
357 _dl_sysdep_message ("scope ", numbuf, ":", NULL);
359 for (cnt = 0; cnt < new->l_scope[scope_cnt]->r_nlist; ++cnt)
360 if (*new->l_scope[scope_cnt]->r_list[cnt]->l_name)
361 _dl_sysdep_message (" ",
362 new->l_scope[scope_cnt]->r_list[cnt]->l_name,
365 _dl_sysdep_message (" <main>", NULL);
367 _dl_sysdep_message ("\n", NULL);