1 /* Handle loading and unloading shared objects for internal libc purposes.
2 Copyright (C) 1999-2002,2004,2005,2006 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Zack Weinberg <zack@rabi.columbia.edu>, 1999.
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, write to the Free
18 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
25 extern int __libc_argc attribute_hidden;
26 extern char **__libc_argv attribute_hidden;
28 extern char **__environ;
30 /* The purpose of this file is to provide wrappers around the dynamic
31 linker error mechanism (similar to dlopen() et al in libdl) which
32 are usable from within libc. Generally we want to throw away the
33 string that dlerror() would return and just pass back a null pointer
34 for errors. This also lets the rest of libc not know about the error
37 Much of this code came from gconv_dl.c with slight modifications. */
41 dlerror_run (void (*operate) (void *), void *args)
44 const char *last_errstring = NULL;
47 (void) GLRO(dl_catch_error) (&objname, &last_errstring, &malloced,
50 int result = last_errstring != NULL;
51 if (result && malloced)
52 free ((char *) last_errstring);
57 /* These functions are called by dlerror_run... */
61 /* Argument to do_dlopen. */
66 /* Return from do_dlopen. */
72 /* Arguments to do_dlsym. */
76 /* Return values of do_dlsym. */
84 struct do_dlopen_args *args = (struct do_dlopen_args *) ptr;
85 /* Open and relocate the shared object. */
86 args->map = GLRO(dl_open) (args->name, args->mode, NULL, __LM_ID_CALLER,
87 __libc_argc, __libc_argv, __environ);
93 struct do_dlsym_args *args = (struct do_dlsym_args *) ptr;
95 args->loadbase = GLRO(dl_lookup_symbol_x) (args->name, args->map, &args->ref,
96 args->map->l_local_scope, NULL, 0,
97 DL_LOOKUP_RETURN_NEWEST, NULL);
101 do_dlclose (void *ptr)
103 GLRO(dl_close) ((struct link_map *) ptr);
106 /* This code is to support __libc_dlopen from __libc_dlopen'ed shared
107 libraries. We need to ensure the statically linked __libc_dlopen
108 etc. functions are used instead of the dynamically loaded. */
111 void *(*dlopen_mode) (const char *name, int mode);
112 void *(*dlsym) (void *map, const char *name);
113 int (*dlclose) (void *map);
117 extern struct dl_open_hook *_dl_open_hook;
118 libc_hidden_proto (_dl_open_hook);
119 struct dl_open_hook *_dl_open_hook __attribute__ ((nocommon));
120 libc_hidden_data_def (_dl_open_hook);
123 do_dlsym_private (void *ptr)
126 struct r_found_version vers;
127 vers.name = "GLIBC_PRIVATE";
129 /* vers.hash = _dl_elf_hash (vers.name); */
130 vers.hash = 0x0963cf85;
131 vers.filename = NULL;
133 struct do_dlsym_args *args = (struct do_dlsym_args *) ptr;
135 l = GLRO(dl_lookup_symbol_x) (args->name, args->map, &args->ref,
136 args->map->l_scope, &vers, 0, 0, NULL);
140 static struct dl_open_hook _dl_open_hook =
142 .dlopen_mode = __libc_dlopen_mode,
143 .dlsym = __libc_dlsym,
144 .dlclose = __libc_dlclose
148 /* ... and these functions call dlerror_run. */
151 __libc_dlopen_mode (const char *name, int mode)
153 struct do_dlopen_args args;
158 if (__builtin_expect (_dl_open_hook != NULL, 0))
159 return _dl_open_hook->dlopen_mode (name, mode);
160 return (dlerror_run (do_dlopen, &args) ? NULL : (void *) args.map);
162 if (dlerror_run (do_dlopen, &args))
165 __libc_register_dl_open_hook (args.map);
166 __libc_register_dlfcn_hook (args.map);
167 return (void *) args.map;
170 libc_hidden_def (__libc_dlopen_mode)
174 __libc_dlsym_private (struct link_map *map, const char *name)
176 struct do_dlsym_args sargs;
180 if (! dlerror_run (do_dlsym_private, &sargs))
181 return DL_SYMBOL_ADDRESS (sargs.loadbase, sargs.ref);
186 __libc_register_dl_open_hook (struct link_map *map)
188 struct dl_open_hook **hook;
190 hook = (struct dl_open_hook **) __libc_dlsym_private (map, "_dl_open_hook");
192 *hook = &_dl_open_hook;
197 __libc_dlsym (void *map, const char *name)
199 struct do_dlsym_args args;
204 if (__builtin_expect (_dl_open_hook != NULL, 0))
205 return _dl_open_hook->dlsym (map, name);
207 return (dlerror_run (do_dlsym, &args) ? NULL
208 : (void *) (DL_SYMBOL_ADDRESS (args.loadbase, args.ref)));
210 libc_hidden_def (__libc_dlsym)
213 __libc_dlclose (void *map)
216 if (__builtin_expect (_dl_open_hook != NULL, 0))
217 return _dl_open_hook->dlclose (map);
219 return dlerror_run (do_dlclose, map);
221 libc_hidden_def (__libc_dlclose)
224 libc_freeres_fn (free_mem)
227 struct r_search_path_elem *d;
229 /* Remove all search directories. */
231 while (d != GLRO(dl_init_all_dirs))
233 struct r_search_path_elem *old = d;
238 /* Remove all additional names added to the objects. */
239 for (Lmid_t ns = 0; ns < DL_NNS; ++ns)
240 for (l = GL(dl_ns)[ns]._ns_loaded; l != NULL; l = l->l_next)
242 struct libname_list *lnp = l->l_libname->next;
244 l->l_libname->next = NULL;
248 struct libname_list *old = lnp;
250 if (! old->dont_free)