1 /* Handle loading and unloading shared objects for internal libc purposes.
2 Copyright (C) 1999, 2000, 2001, 2002 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 /* The purpose of this file is to provide wrappers around the dynamic
26 linker error mechanism (similar to dlopen() et al in libdl) which
27 are usable from within libc. Generally we want to throw away the
28 string that dlerror() would return and just pass back a null pointer
29 for errors. This also lets the rest of libc not know about the error
32 Much of this code came from gconv_dl.c with slight modifications. */
36 dlerror_run (void (*operate) (void *), void *args)
39 const char *last_errstring = NULL;
42 (void) _dl_catch_error (&objname, &last_errstring, operate, args);
44 result = last_errstring != NULL;
45 if (result && last_errstring != _dl_out_of_memory)
46 free ((char *) last_errstring);
51 /* These functions are called by dlerror_run... */
55 /* Argument to do_dlopen. */
60 /* Return from do_dlopen. */
66 /* Arguments to do_dlsym. */
70 /* Return values of do_dlsym. */
78 struct do_dlopen_args *args = (struct do_dlopen_args *) ptr;
79 /* Open and relocate the shared object. */
80 args->map = _dl_open (args->name, args->mode, NULL);
86 struct do_dlsym_args *args = (struct do_dlsym_args *) ptr;
88 args->loadbase = _dl_lookup_symbol (args->name, args->map, &args->ref,
89 args->map->l_local_scope, 0,
90 DL_LOOKUP_RETURN_NEWEST);
94 do_dlclose (void *ptr)
96 _dl_close ((struct link_map *) ptr);
99 /* This code is to support __libc_dlopen from __libc_dlopen'ed shared
100 libraries. We need to ensure the statically linked __libc_dlopen
101 etc. functions are used instead of the dynamically loaded. */
104 void *(*dlopen_mode) (const char *name, int mode);
105 void *(*dlsym) (void *map, const char *name);
106 int (*dlclose) (void *map);
110 extern struct dl_open_hook *_dl_open_hook;
111 libc_hidden_proto (_dl_open_hook);
112 struct dl_open_hook *_dl_open_hook __attribute__((nocommon));
113 libc_hidden_data_def (_dl_open_hook);
116 do_dlsym_private (void *ptr)
119 struct r_found_version vers;
120 vers.name = "GLIBC_PRIVATE";
122 /* vers.hash = _dl_elf_hash (version); */
123 vers.hash = 0x0963cf85;
124 /* FIXME: Shouldn't we use libc.so.6* here? */
125 vers.filename = NULL;
127 struct do_dlsym_args *args = (struct do_dlsym_args *) ptr;
129 l = _dl_lookup_versioned_symbol (args->name, args->map,
130 &args->ref, args->map->l_scope,
135 static struct dl_open_hook _dl_open_hook =
137 .dlopen_mode = __libc_dlopen_mode,
138 .dlsym = __libc_dlsym,
139 .dlclose = __libc_dlclose
143 /* ... and these functions call dlerror_run. */
146 __libc_dlopen_mode (const char *name, int mode)
148 struct do_dlopen_args args;
153 if (__builtin_expect (_dl_open_hook != NULL, 0))
154 return _dl_open_hook->dlopen_mode (name, mode);
155 return (dlerror_run (do_dlopen, &args) ? NULL : (void *) args.map);
157 if (dlerror_run (do_dlopen, &args))
160 struct do_dlsym_args sargs;
161 sargs.map = args.map;
162 sargs.name = "_dl_open_hook";
164 if (! dlerror_run (do_dlsym_private, &sargs))
166 struct dl_open_hook **hook
167 = (struct dl_open_hook **)
168 (DL_SYMBOL_ADDRESS (sargs.loadbase, sargs.ref));
170 *hook = &_dl_open_hook;
173 return (void *) args.map;
178 __libc_dlsym (void *map, const char *name)
180 struct do_dlsym_args args;
185 if (__builtin_expect (_dl_open_hook != NULL, 0))
186 return _dl_open_hook->dlsym (map, name);
188 return (dlerror_run (do_dlsym, &args) ? NULL
189 : (void *) (DL_SYMBOL_ADDRESS (args.loadbase, args.ref)));
193 __libc_dlclose (void *map)
196 if (__builtin_expect (_dl_open_hook != NULL, 0))
197 return _dl_open_hook->dlclose (map);
199 return dlerror_run (do_dlclose, map);
203 libc_freeres_fn (free_mem)
206 struct r_search_path_elem *d;
208 /* Remove all search directories. */
210 while (d != GL(dl_init_all_dirs))
212 struct r_search_path_elem *old = d;
217 /* Remove all additional names added to the objects. */
218 for (l = GL(dl_loaded); l != NULL; l = l->l_next)
220 struct libname_list *lnp = l->l_libname->next;
222 l->l_libname->next = NULL;
226 struct libname_list *old = lnp;
228 if (! old->dont_free)