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>
34 #include <stdio-common/_itoa.h>
37 extern ElfW(Addr) _dl_sysdep_start (void **start_argptr,
38 void (*dl_main) (const ElfW(Phdr) *phdr,
40 ElfW(Addr) *user_entry));
41 weak_extern (BP_SYM (_dl_sysdep_start))
43 /* This function is used to unload the cache file if necessary. */
44 extern void _dl_unload_cache (void);
46 extern int __libc_multiple_libcs; /* Defined in init-first.c. */
48 extern int __libc_argc;
49 extern char **__libc_argv;
51 extern char **__environ;
53 extern int _dl_lazy; /* Do we do lazy relocations? */
55 /* Undefine the following for debugging. */
56 /* #define SCOPE_DEBUG 1 */
58 static void show_scope (struct link_map *new);
61 /* During the program run we must not modify the global data of
62 loaded shared object simultanously in two threads. Therefore we
63 protect `_dl_open' and `_dl_close' in dl-close.c.
65 This must be a recursive lock since the initializer function of
66 the loaded object might as well require a call to this function.
67 At this time it is not anymore a problem to modify the tables. */
68 __libc_lock_define (extern, _dl_load_lock)
70 extern size_t _dl_platformlen;
72 /* We must be carefull not to leave us in an inconsistent state. Thus we
73 catch any error and re-raise it after cleaning up. */
85 add_to_global (struct link_map *new)
87 struct link_map **new_global;
88 unsigned int to_add = 0;
91 /* Count the objects we have to put in the global scope. */
92 for (cnt = 0; cnt < new->l_searchlist.r_nlist; ++cnt)
93 if (new->l_searchlist.r_list[cnt]->l_global == 0)
96 /* The symbols of the new objects and its dependencies are to be
97 introduced into the global scope that will be used to resolve
98 references from other dynamically-loaded objects.
100 The global scope is the searchlist in the main link map. We
101 extend this list if necessary. There is one problem though:
102 since this structure was allocated very early (before the libc
103 is loaded) the memory it uses is allocated by the malloc()-stub
104 in the ld.so. When we come here these functions are not used
105 anymore. Instead the malloc() implementation of the libc is
106 used. But this means the block from the main map cannot be used
107 in an realloc() call. Therefore we allocate a completely new
108 array the first time we have to add something to the locale scope. */
110 if (_dl_global_scope_alloc == 0)
112 /* This is the first dynamic object given global scope. */
113 _dl_global_scope_alloc = _dl_main_searchlist->r_nlist + to_add + 8;
114 new_global = (struct link_map **)
115 malloc (_dl_global_scope_alloc * sizeof (struct link_map *));
116 if (new_global == NULL)
118 _dl_global_scope_alloc = 0;
120 _dl_signal_error (ENOMEM, new->l_libname->name,
121 N_("cannot extend global scope"));
125 /* Copy over the old entries. */
126 memcpy (new_global, _dl_main_searchlist->r_list,
127 (_dl_main_searchlist->r_nlist * sizeof (struct link_map *)));
129 _dl_main_searchlist->r_list = new_global;
131 else if (_dl_main_searchlist->r_nlist + to_add > _dl_global_scope_alloc)
133 /* We have to extend the existing array of link maps in the
135 new_global = (struct link_map **)
136 realloc (_dl_main_searchlist->r_list,
137 ((_dl_global_scope_alloc + to_add + 8)
138 * sizeof (struct link_map *)));
139 if (new_global == NULL)
142 _dl_global_scope_alloc += to_add + 8;
143 _dl_main_searchlist->r_list = new_global;
146 /* Now add the new entries. */
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 _dl_main_searchlist->r_list[_dl_main_searchlist->r_nlist] = map;
155 ++_dl_main_searchlist->r_nlist;
159 /* XXX Do we have to add something to r_dupsearchlist??? --drepper */
165 dl_open_worker (void *a)
167 struct dl_open_args *args = a;
168 const char *file = args->file;
169 int mode = args->mode;
170 struct link_map *new, *l;
175 /* Maybe we have to expand a DST. */
176 dst = strchr (file, '$');
179 const void *caller = args->caller;
180 size_t len = strlen (file);
182 struct link_map *call_map;
185 /* DSTs must not appear in SUID/SGID programs. */
186 if (__libc_enable_secure)
187 /* This is an error. */
188 _dl_signal_error (0, "dlopen",
189 N_("DST not allowed in SUID/SGID programs"));
191 /* We have to find out from which object the caller is calling.
192 Find the highest-addressed object that ADDRESS is not below. */
194 for (l = _dl_loaded; l; l = l->l_next)
195 if (l->l_addr != 0 /* Make sure we do not currently set this map up
197 && caller >= (const void *) l->l_map_start
198 && caller < (const void *) l->l_map_end)
200 /* There must be exactly one DSO for the range of the virtual
201 memory. Otherwise something is really broken. */
206 if (call_map == NULL)
207 /* In this case we assume this is the main application. */
208 call_map = _dl_loaded;
210 /* Determine how much space we need. We have to allocate the
212 required = DL_DST_REQUIRED (call_map, file, len, _dl_dst_count (dst, 0));
214 /* Get space for the new file name. */
215 new_file = (char *) alloca (required + 1);
217 /* Generate the new file name. */
218 DL_DST_SUBSTITUTE (call_map, file, new_file, 0);
220 /* If the substitution failed don't try to load. */
221 if (*new_file == '\0')
222 _dl_signal_error (0, "dlopen",
223 N_("empty dynamic string token substitution"));
225 /* Now we have a new file name. */
229 /* Load the named object. */
230 args->map = new = _dl_map_object (NULL, file, 0, lt_loaded, 0,
233 /* If the pointer returned is NULL this means the RTLD_NOLOAD flag is
234 set and the object is not already loaded. */
237 assert (mode & RTLD_NOLOAD);
241 /* It was already open. */
242 if (new->l_searchlist.r_list != NULL)
244 /* Let the user know about the opencount. */
245 if (__builtin_expect (_dl_debug_files, 0))
249 buf[sizeof buf - 1] = '\0';
251 _dl_debug_message (1, "opening file=", new->l_name,
253 _itoa_word (new->l_opencount,
254 buf + sizeof buf - 1, 10, 0),
258 /* If the user requested the object t be in the global namespace
259 but it is not so far, add it now. */
260 if ((mode & RTLD_GLOBAL) && new->l_global == 0)
261 (void) add_to_global (new);
263 /* Increment just the reference counter of the object. */
269 /* Load that object's dependencies. */
270 _dl_map_object_deps (new, NULL, 0, 0);
272 /* Increment the open count for all dependencies. */
273 for (i = 0; i < new->l_searchlist.r_nlist; ++i)
274 ++new->l_searchlist.r_list[i]->l_opencount;
276 /* So far, so good. Now check the versions. */
277 for (i = 0; i < new->l_searchlist.r_nlist; ++i)
278 if (new->l_searchlist.r_list[i]->l_versions == NULL)
279 (void) _dl_check_map_versions (new->l_searchlist.r_list[i], 0, 0);
285 /* Only do lazy relocation if `LD_BIND_NOW' is not set. */
286 lazy = (mode & RTLD_BINDING_MASK) == RTLD_LAZY && _dl_lazy;
288 /* Relocate the objects loaded. We do this in reverse order so that copy
289 relocs of earlier objects overwrite the data written by later objects. */
296 if (! l->l_relocated)
299 if (_dl_profile != NULL)
301 /* If this here is the shared object which we want to profile
302 make sure the profile is started. We can find out whether
303 this is necessary or not by observing the `_dl_profile_map'
304 variable. If was NULL but is not NULL afterwars we must
305 start the profiling. */
306 struct link_map *old_profile_map = _dl_profile_map;
308 _dl_relocate_object (l, l->l_scope, 1, 1);
310 if (old_profile_map == NULL && _dl_profile_map != NULL)
311 /* We must prepare the profiling. */
312 _dl_start_profile (_dl_profile_map, _dl_profile_output);
316 _dl_relocate_object (l, l->l_scope, lazy, 0);
324 /* Run the initializer functions of new objects. */
325 _dl_init (new, __libc_argc, __libc_argv, __environ);
327 /* Now we can make the new map available in the global scope. */
328 if (mode & RTLD_GLOBAL)
329 /* Move the object in the global namespace. */
330 if (add_to_global (new) != 0)
334 /* Mark the object as not deletable if the RTLD_NODELETE flags was
336 if (__builtin_expect (mode & RTLD_NODELETE, 0))
337 new->l_flags_1 |= DF_1_NODELETE;
339 if (_dl_sysdep_start == NULL)
340 /* We must be the static _dl_open in libc.a. A static program that
341 has loaded a dynamic object now has competition. */
342 __libc_multiple_libcs = 1;
344 /* Let the user know about the opencount. */
345 if (__builtin_expect (_dl_debug_files, 0))
349 buf[sizeof buf - 1] = '\0';
351 _dl_debug_message (1, "opening file=", new->l_name,
353 _itoa_word (new->l_opencount,
354 buf + sizeof buf - 1, 10, 0),
362 _dl_open (const char *file, int mode, const void *caller)
364 struct dl_open_args args;
366 const char *errstring;
369 if ((mode & RTLD_BINDING_MASK) == 0)
370 /* One of the flags must be set. */
371 _dl_signal_error (EINVAL, file, N_("invalid mode for dlopen()"));
373 /* Make sure we are alone. */
374 __libc_lock_lock (_dl_load_lock);
378 args.caller = caller;
380 errcode = _dl_catch_error (&objname, &errstring, dl_open_worker, &args);
383 /* We must munmap() the cache file. */
387 /* Release the lock. */
388 __libc_lock_unlock (_dl_load_lock);
392 /* Some error occurred during loading. */
393 char *local_errstring;
395 /* Remove the object from memory. It may be in an inconsistent
396 state if relocation failed, for example. */
398 _dl_close (args.map);
400 /* Make a local copy of the error string so that we can release the
401 memory allocated for it. */
402 local_errstring = strdupa (errstring);
403 if (errstring != _dl_out_of_memory)
404 free ((char *) errstring);
406 /* Reraise the error. */
407 _dl_signal_error (errcode, objname, local_errstring);
418 show_scope (struct link_map *new)
422 for (scope_cnt = 0; new->l_scope[scope_cnt] != NULL; ++scope_cnt)
427 numbuf[0] = '0' + scope_cnt;
429 _dl_sysdep_message ("scope ", numbuf, ":", NULL);
431 for (cnt = 0; cnt < new->l_scope[scope_cnt]->r_nlist; ++cnt)
432 if (*new->l_scope[scope_cnt]->r_list[cnt]->l_name)
433 _dl_sysdep_message (" ",
434 new->l_scope[scope_cnt]->r_list[cnt]->l_name,
437 _dl_sysdep_message (" <main>", NULL);
439 _dl_sysdep_message ("\n", NULL);