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1 | /* Look up a versioned symbol in a shared object loaded by `dlopen'. | |
2 | Copyright (C) 1995-2024 Free Software Foundation, Inc. | |
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 | |
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. | |
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 | |
13 | Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public | |
16 | License along with the GNU C Library; if not, see | |
17 | <https://www.gnu.org/licenses/>. */ | |
18 | ||
19 | #include <dlfcn.h> | |
20 | #include <ldsodefs.h> | |
21 | #include <shlib-compat.h> | |
22 | #include <stddef.h> | |
23 | ||
24 | struct dlvsym_args | |
25 | { | |
26 | /* The arguments to dlvsym_doit. */ | |
27 | void *handle; | |
28 | const char *name; | |
29 | const char *version; | |
30 | void *who; | |
31 | ||
32 | /* The return values of dlvsym_doit. */ | |
33 | void *sym; | |
34 | }; | |
35 | ||
36 | static void | |
37 | dlvsym_doit (void *a) | |
38 | { | |
39 | struct dlvsym_args *args = (struct dlvsym_args *) a; | |
40 | ||
41 | args->sym = _dl_vsym (args->handle, args->name, args->version, args->who); | |
42 | } | |
43 | ||
44 | static void * | |
45 | dlvsym_implementation (void *handle, const char *name, const char *version, | |
46 | void *dl_caller) | |
47 | { | |
48 | struct dlvsym_args args; | |
49 | args.who = dl_caller; | |
50 | args.handle = handle; | |
51 | args.name = name; | |
52 | args.version = version; | |
53 | ||
54 | /* Protect against concurrent loads and unloads. */ | |
55 | __rtld_lock_lock_recursive (GL(dl_load_lock)); | |
56 | ||
57 | void *result = (_dlerror_run (dlvsym_doit, &args) ? NULL : args.sym); | |
58 | ||
59 | __rtld_lock_unlock_recursive (GL(dl_load_lock)); | |
60 | ||
61 | return result; | |
62 | } | |
63 | ||
64 | #ifdef SHARED | |
65 | void * | |
66 | ___dlvsym (void *handle, const char *name, const char *version) | |
67 | { | |
68 | if (GLRO (dl_dlfcn_hook) != NULL) | |
69 | return GLRO (dl_dlfcn_hook)->dlvsym (handle, name, version, | |
70 | RETURN_ADDRESS (0)); | |
71 | else | |
72 | return dlvsym_implementation (handle, name, version, RETURN_ADDRESS (0)); | |
73 | } | |
74 | versioned_symbol (libc, ___dlvsym, dlvsym, GLIBC_2_34); | |
75 | ||
76 | # if OTHER_SHLIB_COMPAT (libdl, GLIBC_2_1, GLIBC_2_34) | |
77 | compat_symbol (libdl, ___dlvsym, dlvsym, GLIBC_2_1); | |
78 | # endif | |
79 | ||
80 | #else /* !SHARED */ | |
81 | /* Also used with _dlfcn_hook. */ | |
82 | void * | |
83 | __dlvsym (void *handle, const char *name, const char *version, void *dl_caller) | |
84 | { | |
85 | return dlvsym_implementation (handle, name, version, dl_caller); | |
86 | } | |
87 | ||
88 | void * | |
89 | ___dlvsym (void *handle, const char *name, const char *version) | |
90 | { | |
91 | return __dlvsym (handle, name, version, RETURN_ADDRESS (0)); | |
92 | } | |
93 | weak_alias (___dlvsym, dlvsym) | |
94 | #endif /* !SHARED */ |