Update.
[glibc.git] / elf / dl-sym.c
blobc7c737804ec7e6871f3ddb33a8d4de386e427bb8
1 /* Look up a symbol in a shared object loaded by `dlopen'.
2 Copyright (C) 1999, 2000, 2001, 2002, 2004 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 Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the 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 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
18 02111-1307 USA. */
20 #include <stddef.h>
21 #include <setjmp.h>
22 #include <libintl.h>
24 #include <dlfcn.h>
25 #include <ldsodefs.h>
26 #include <dl-hash.h>
27 #ifdef USE_TLS
28 # include <dl-tls.h>
29 #endif
32 #if defined USE_TLS && defined SHARED
33 /* Systems which do not have tls_index also probably have to define
34 DONT_USE_TLS_INDEX. */
36 # ifndef __TLS_GET_ADDR
37 # define __TLS_GET_ADDR __tls_get_addr
38 # endif
40 /* Return the symbol address given the map of the module it is in and
41 the symbol record. This is used in dl-sym.c. */
42 static void *
43 internal_function
44 _dl_tls_symaddr (struct link_map *map, const ElfW(Sym) *ref)
46 # ifndef DONT_USE_TLS_INDEX
47 tls_index tmp =
49 .ti_module = map->l_tls_modid,
50 .ti_offset = ref->st_value
53 return __TLS_GET_ADDR (&tmp);
54 # else
55 return __TLS_GET_ADDR (map->l_tls_modid, ref->st_value);
56 # endif
58 #endif
61 static void *
62 internal_function
63 do_sym (void *handle, const char *name, void *who,
64 struct r_found_version *vers, int flags)
66 const ElfW(Sym) *ref = NULL;
67 lookup_t result;
68 ElfW(Addr) caller = (ElfW(Addr)) who;
70 /* If the address is not recognized the call comes from the main
71 program (we hope). */
72 struct link_map *match = GL(dl_loaded);
74 /* Find the highest-addressed object that CALLER is not below. */
75 for (struct link_map *l = GL(dl_loaded); l != NULL; l = l->l_next)
76 if (caller >= l->l_map_start && caller < l->l_map_end)
78 /* There must be exactly one DSO for the range of the virtual
79 memory. Otherwise something is really broken. */
80 match = l;
81 break;
84 if (handle == RTLD_DEFAULT)
85 /* Search the global scope. */
86 result = GLRO(dl_lookup_symbol_x) (name, match, &ref, match->l_scope,
87 vers, 0, flags|DL_LOOKUP_ADD_DEPENDENCY,
88 NULL);
89 else if (handle == RTLD_NEXT)
91 if (__builtin_expect (match == GL(dl_loaded), 0))
93 if (! GL(dl_loaded)
94 || caller < GL(dl_loaded)->l_map_start
95 || caller >= GL(dl_loaded)->l_map_end)
96 GLRO(dl_signal_error) (0, NULL, NULL, N_("\
97 RTLD_NEXT used in code not dynamically loaded"));
100 struct link_map *l = match;
101 while (l->l_loader != NULL)
102 l = l->l_loader;
104 result = GLRO(dl_lookup_symbol_x) (name, l, &ref, l->l_local_scope,
105 vers, 0, 0, match);
107 else
109 /* Search the scope of the given object. */
110 struct link_map *map = handle;
111 result = GLRO(dl_lookup_symbol_x) (name, map, &ref, map->l_local_scope,
112 vers, 0, flags, NULL);
115 if (ref != NULL)
117 #if defined USE_TLS && defined SHARED
118 if (ELFW(ST_TYPE) (ref->st_info) == STT_TLS)
119 /* The found symbol is a thread-local storage variable.
120 Return the address for to the current thread. */
121 return _dl_tls_symaddr (result, ref);
122 #endif
124 return DL_SYMBOL_ADDRESS (result, ref);
127 return NULL;
131 void *
132 internal_function
133 _dl_vsym (void *handle, const char *name, const char *version, void *who)
135 struct r_found_version vers;
137 /* Compute hash value to the version string. */
138 vers.name = version;
139 vers.hidden = 1;
140 vers.hash = _dl_elf_hash (version);
141 /* We don't have a specific file where the symbol can be found. */
142 vers.filename = NULL;
144 return do_sym (handle, name, who, &vers, 0);
148 void *
149 internal_function
150 _dl_sym (void *handle, const char *name, void *who)
152 return do_sym (handle, name, who, NULL, DL_LOOKUP_RETURN_NEWEST);