1/* Look up a versioned symbol in a shared object loaded by `dlopen'.
2 Copyright (C) 1995-2023 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
24struct 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
36static void
37dlvsym_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
44static void *
45dlvsym_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
65void *
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}
74versioned_symbol (libc, ___dlvsym, dlvsym, GLIBC_2_34);
75
76# if OTHER_SHLIB_COMPAT (libdl, GLIBC_2_1, GLIBC_2_34)
77compat_symbol (libdl, ___dlvsym, dlvsym, GLIBC_2_1);
78# endif
79
80#else /* !SHARED */
81/* Also used with _dlfcn_hook. */
82void *
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
88void *
89___dlvsym (void *handle, const char *name, const char *version)
90{
91 return __dlvsym (handle, name, version, RETURN_ADDRESS (0));
92}
93weak_alias (___dlvsym, dlvsym)
94#endif /* !SHARED */
95