Update.
[glibc.git] / elf / dl-libc.c
bloba8b851c0902bac299e194e93f56fac972708795a
1 /* Handle loading and unloading shared objects for internal libc purposes.
2 Copyright (C) 1999, 2000, 2001, 2002, 2004 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
19 02111-1307 USA. */
21 #include <dlfcn.h>
22 #include <stdlib.h>
23 #include <ldsodefs.h>
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
30 handling mechanism.
32 Much of this code came from gconv_dl.c with slight modifications. */
34 static int
35 internal_function
36 dlerror_run (void (*operate) (void *), void *args)
38 const char *objname;
39 const char *last_errstring = NULL;
40 int result;
42 (void) GLRO(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);
48 return result;
51 /* These functions are called by dlerror_run... */
53 struct do_dlopen_args
55 /* Argument to do_dlopen. */
56 const char *name;
57 /* Opening mode. */
58 int mode;
60 /* Return from do_dlopen. */
61 struct link_map *map;
64 struct do_dlsym_args
66 /* Arguments to do_dlsym. */
67 struct link_map *map;
68 const char *name;
70 /* Return values of do_dlsym. */
71 lookup_t loadbase;
72 const ElfW(Sym) *ref;
75 static void
76 do_dlopen (void *ptr)
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);
83 static void
84 do_dlsym (void *ptr)
86 struct do_dlsym_args *args = (struct do_dlsym_args *) ptr;
87 args->ref = NULL;
88 args->loadbase = GLRO(dl_lookup_symbol_x) (args->name, args->map, &args->ref,
89 args->map->l_local_scope, NULL, 0,
90 DL_LOOKUP_RETURN_NEWEST, NULL);
93 static void
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. */
102 struct dl_open_hook
104 void *(*dlopen_mode) (const char *name, int mode);
105 void *(*dlsym) (void *map, const char *name);
106 int (*dlclose) (void *map);
109 #ifdef SHARED
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);
114 #else
115 static void
116 do_dlsym_private (void *ptr)
118 lookup_t l;
119 struct r_found_version vers;
120 vers.name = "GLIBC_PRIVATE";
121 vers.hidden = 1;
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;
128 args->ref = NULL;
129 l = GLRO(dl_lookup_symbol_x) (args->name, args->map, &args->ref,
130 args->map->l_scope, &vers, 0, 0, NULL);
131 args->loadbase = l;
134 static struct dl_open_hook _dl_open_hook =
136 .dlopen_mode = __libc_dlopen_mode,
137 .dlsym = __libc_dlsym,
138 .dlclose = __libc_dlclose
140 #endif
142 /* ... and these functions call dlerror_run. */
144 void *
145 __libc_dlopen_mode (const char *name, int mode)
147 struct do_dlopen_args args;
148 args.name = name;
149 args.mode = mode;
151 #ifdef SHARED
152 if (__builtin_expect (_dl_open_hook != NULL, 0))
153 return _dl_open_hook->dlopen_mode (name, mode);
154 return (dlerror_run (do_dlopen, &args) ? NULL : (void *) args.map);
155 #else
156 if (dlerror_run (do_dlopen, &args))
157 return NULL;
159 struct do_dlsym_args sargs;
160 sargs.map = args.map;
161 sargs.name = "_dl_open_hook";
163 if (! dlerror_run (do_dlsym_private, &sargs))
165 struct dl_open_hook **hook
166 = (struct dl_open_hook **)
167 (DL_SYMBOL_ADDRESS (sargs.loadbase, sargs.ref));
168 if (hook != NULL)
169 *hook = &_dl_open_hook;
172 return (void *) args.map;
173 #endif
175 libc_hidden_def (__libc_dlopen_mode)
177 void *
178 __libc_dlsym (void *map, const char *name)
180 struct do_dlsym_args args;
181 args.map = map;
182 args.name = name;
184 #ifdef SHARED
185 if (__builtin_expect (_dl_open_hook != NULL, 0))
186 return _dl_open_hook->dlsym (map, name);
187 #endif
188 return (dlerror_run (do_dlsym, &args) ? NULL
189 : (void *) (DL_SYMBOL_ADDRESS (args.loadbase, args.ref)));
191 libc_hidden_def (__libc_dlsym)
194 __libc_dlclose (void *map)
196 #ifdef SHARED
197 if (__builtin_expect (_dl_open_hook != NULL, 0))
198 return _dl_open_hook->dlclose (map);
199 #endif
200 return dlerror_run (do_dlclose, map);
202 libc_hidden_def (__libc_dlclose)
205 libc_freeres_fn (free_mem)
207 struct link_map *l;
208 struct r_search_path_elem *d;
210 /* Remove all search directories. */
211 d = GL(dl_all_dirs);
212 while (d != GLRO(dl_init_all_dirs))
214 struct r_search_path_elem *old = d;
215 d = d->next;
216 free (old);
219 /* Remove all additional names added to the objects. */
220 for (l = GL(dl_loaded); l != NULL; l = l->l_next)
222 struct libname_list *lnp = l->l_libname->next;
224 l->l_libname->next = NULL;
226 while (lnp != NULL)
228 struct libname_list *old = lnp;
229 lnp = lnp->next;
230 if (! old->dont_free)
231 free (old);