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94e365c6 | 1 | /* Look up a symbol in a shared object loaded by `dlopen'. |
2b778ceb | 2 | Copyright (C) 1999-2021 Free Software Foundation, Inc. |
94e365c6 UD |
3 | This file is part of the GNU C Library. |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
41bdb6e2 AJ |
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. | |
94e365c6 UD |
9 | |
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 | |
41bdb6e2 | 13 | Lesser General Public License for more details. |
94e365c6 | 14 | |
41bdb6e2 | 15 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 | 16 | License along with the GNU C Library; if not, see |
5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
94e365c6 | 18 | |
1100f849 | 19 | #include <assert.h> |
94e365c6 UD |
20 | #include <stddef.h> |
21 | #include <setjmp.h> | |
176790a7 | 22 | #include <stdlib.h> |
94e365c6 UD |
23 | #include <libintl.h> |
24 | ||
25 | #include <dlfcn.h> | |
26 | #include <ldsodefs.h> | |
27 | #include <dl-hash.h> | |
609cf614 | 28 | #include <sysdep-cancel.h> |
11bf311e | 29 | #include <dl-tls.h> |
42675c6f | 30 | #include <dl-irel.h> |
c76147af | 31 | #include <dl-sym-post.h> |
154d10bd UD |
32 | |
33 | ||
11bf311e | 34 | #ifdef SHARED |
154d10bd UD |
35 | /* Systems which do not have tls_index also probably have to define |
36 | DONT_USE_TLS_INDEX. */ | |
37 | ||
38 | # ifndef __TLS_GET_ADDR | |
39 | # define __TLS_GET_ADDR __tls_get_addr | |
40 | # endif | |
41 | ||
42 | /* Return the symbol address given the map of the module it is in and | |
43 | the symbol record. This is used in dl-sym.c. */ | |
44 | static void * | |
154d10bd UD |
45 | _dl_tls_symaddr (struct link_map *map, const ElfW(Sym) *ref) |
46 | { | |
47 | # ifndef DONT_USE_TLS_INDEX | |
48 | tls_index tmp = | |
49 | { | |
50 | .ti_module = map->l_tls_modid, | |
51 | .ti_offset = ref->st_value | |
52 | }; | |
53 | ||
54 | return __TLS_GET_ADDR (&tmp); | |
55 | # else | |
56 | return __TLS_GET_ADDR (map->l_tls_modid, ref->st_value); | |
57 | # endif | |
58 | } | |
59 | #endif | |
60 | ||
94e365c6 | 61 | |
1100f849 UD |
62 | struct call_dl_lookup_args |
63 | { | |
64 | /* Arguments to do_dlsym. */ | |
65 | struct link_map *map; | |
66 | const char *name; | |
1100f849 UD |
67 | struct r_found_version *vers; |
68 | int flags; | |
69 | ||
70 | /* Return values of do_dlsym. */ | |
71 | lookup_t loadbase; | |
72 | const ElfW(Sym) **refp; | |
73 | }; | |
74 | ||
75 | static void | |
76 | call_dl_lookup (void *ptr) | |
77 | { | |
78 | struct call_dl_lookup_args *args = (struct call_dl_lookup_args *) ptr; | |
79 | args->map = GLRO(dl_lookup_symbol_x) (args->name, args->map, args->refp, | |
c0a777e8 | 80 | args->map->l_scope, args->vers, 0, |
1100f849 UD |
81 | args->flags, NULL); |
82 | } | |
83 | ||
53761a8b | 84 | static void * |
f0323886 UD |
85 | do_sym (void *handle, const char *name, void *who, |
86 | struct r_found_version *vers, int flags) | |
94e365c6 | 87 | { |
94e365c6 | 88 | const ElfW(Sym) *ref = NULL; |
c0282c06 | 89 | lookup_t result; |
2b7238dd | 90 | ElfW(Addr) caller = (ElfW(Addr)) who; |
94e365c6 | 91 | |
4a2ab584 FW |
92 | /* Link map of the caller if needed. */ |
93 | struct link_map *match = NULL; | |
2b7238dd | 94 | |
94e365c6 | 95 | if (handle == RTLD_DEFAULT) |
1100f849 | 96 | { |
c76147af | 97 | match = _dl_sym_find_caller_link_map (caller); |
4a2ab584 | 98 | |
1100f849 UD |
99 | /* Search the global scope. We have the simple case where |
100 | we look up in the scope of an object which was part of | |
101 | the initial binary. And then the more complex part | |
102 | where the object is dynamically loaded and the scope | |
103 | array can change. */ | |
e4eb675d | 104 | if (RTLD_SINGLE_THREAD_P) |
1100f849 | 105 | result = GLRO(dl_lookup_symbol_x) (name, match, &ref, |
c0a777e8 | 106 | match->l_scope, vers, 0, |
1100f849 UD |
107 | flags | DL_LOOKUP_ADD_DEPENDENCY, |
108 | NULL); | |
109 | else | |
110 | { | |
1100f849 UD |
111 | struct call_dl_lookup_args args; |
112 | args.name = name; | |
113 | args.map = match; | |
1100f849 | 114 | args.vers = vers; |
b90395e6 UD |
115 | args.flags |
116 | = flags | DL_LOOKUP_ADD_DEPENDENCY | DL_LOOKUP_GSCOPE_LOCK; | |
1100f849 UD |
117 | args.refp = &ref; |
118 | ||
e4eb675d | 119 | THREAD_GSCOPE_SET_FLAG (); |
2449ae7b FW |
120 | struct dl_exception exception; |
121 | int err = _dl_catch_exception (&exception, call_dl_lookup, &args); | |
e4eb675d | 122 | THREAD_GSCOPE_RESET_FLAG (); |
2449ae7b FW |
123 | if (__glibc_unlikely (exception.errstring != NULL)) |
124 | _dl_signal_exception (err, &exception, NULL); | |
1100f849 UD |
125 | |
126 | result = args.map; | |
127 | } | |
128 | } | |
94e365c6 UD |
129 | else if (handle == RTLD_NEXT) |
130 | { | |
c76147af | 131 | match = _dl_sym_find_caller_link_map (caller); |
4a2ab584 | 132 | |
a1ffb40e | 133 | if (__glibc_unlikely (match == GL(dl_ns)[LM_ID_BASE]._ns_loaded)) |
2373b30e | 134 | { |
173a06ec UD |
135 | if (match == NULL |
136 | || caller < match->l_map_start | |
137 | || caller >= match->l_map_end) | |
9e78f6f6 | 138 | _dl_signal_error (0, NULL, NULL, N_("\ |
94e365c6 | 139 | RTLD_NEXT used in code not dynamically loaded")); |
2373b30e | 140 | } |
94e365c6 | 141 | |
53761a8b | 142 | struct link_map *l = match; |
f92338be | 143 | while (l->l_loader != NULL) |
94e365c6 UD |
144 | l = l->l_loader; |
145 | ||
74c5693b | 146 | result = GLRO(dl_lookup_symbol_x) (name, match, &ref, l->l_local_scope, |
53761a8b | 147 | vers, 0, 0, match); |
94e365c6 UD |
148 | } |
149 | else | |
150 | { | |
151 | /* Search the scope of the given object. */ | |
152 | struct link_map *map = handle; | |
021723ab | 153 | result = GLRO(dl_lookup_symbol_x) (name, map, &ref, map->l_local_scope, |
53761a8b | 154 | vers, 0, flags, NULL); |
94e365c6 UD |
155 | } |
156 | ||
f92338be | 157 | if (ref != NULL) |
aed283dd | 158 | { |
9dcafc55 UD |
159 | void *value; |
160 | ||
11bf311e | 161 | #ifdef SHARED |
aed283dd UD |
162 | if (ELFW(ST_TYPE) (ref->st_info) == STT_TLS) |
163 | /* The found symbol is a thread-local storage variable. | |
164 | Return the address for to the current thread. */ | |
9dcafc55 UD |
165 | value = _dl_tls_symaddr (result, ref); |
166 | else | |
167 | #endif | |
168 | value = DL_SYMBOL_ADDRESS (result, ref); | |
169 | ||
c76147af | 170 | return _dl_sym_post (result, ref, value, caller, match); |
aed283dd | 171 | } |
5e76a346 | 172 | |
94e365c6 UD |
173 | return NULL; |
174 | } | |
53761a8b UD |
175 | |
176 | ||
53761a8b | 177 | void * |
53761a8b UD |
178 | _dl_vsym (void *handle, const char *name, const char *version, void *who) |
179 | { | |
180 | struct r_found_version vers; | |
181 | ||
182 | /* Compute hash value to the version string. */ | |
183 | vers.name = version; | |
184 | vers.hidden = 1; | |
185 | vers.hash = _dl_elf_hash (version); | |
186 | /* We don't have a specific file where the symbol can be found. */ | |
187 | vers.filename = NULL; | |
188 | ||
f0323886 | 189 | return do_sym (handle, name, who, &vers, 0); |
53761a8b UD |
190 | } |
191 | ||
192 | ||
193 | void * | |
53761a8b UD |
194 | _dl_sym (void *handle, const char *name, void *who) |
195 | { | |
f0323886 | 196 | return do_sym (handle, name, who, NULL, DL_LOOKUP_RETURN_NEWEST); |
53761a8b | 197 | } |