1/* Look up a versioned symbol in a shared object loaded by `dlopen'.
2 Copyright (C) 1995-2020 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 <stddef.h>
21
22#include <ldsodefs.h>
23
24#if !defined SHARED && IS_IN (libdl)
25
26void *
27weak_function
28dlvsym (void *handle, const char *name, const char *version_str)
29{
30 return __dlvsym (handle, name, version_str, RETURN_ADDRESS (0));
31}
32
33#else
34
35struct dlvsym_args
36{
37 /* The arguments to dlvsym_doit. */
38 void *handle;
39 const char *name;
40 const char *version;
41 void *who;
42
43 /* The return values of dlvsym_doit. */
44 void *sym;
45};
46
47
48static void
49dlvsym_doit (void *a)
50{
51 struct dlvsym_args *args = (struct dlvsym_args *)a;
52
53 args->sym = _dl_vsym (args->handle, args->name, args->version, args->who);
54}
55
56void *
57__dlvsym (void *handle, const char *name, const char *version_str
58 DL_CALLER_DECL)
59{
60# ifdef SHARED
61 if (!rtld_active ())
62 return _dlfcn_hook->dlvsym (handle, name, version_str, DL_CALLER);
63# endif
64
65 struct dlvsym_args args;
66 args.handle = handle;
67 args.name = name;
68 args.who = DL_CALLER;
69 args.version = version_str;
70
71 /* Protect against concurrent loads and unloads. */
72 __rtld_lock_lock_recursive (GL(dl_load_lock));
73
74 void *result = (_dlerror_run (dlvsym_doit, &args) ? NULL : args.sym);
75
76 __rtld_lock_unlock_recursive (GL(dl_load_lock));
77
78 return result;
79}
80# ifdef SHARED
81weak_alias (__dlvsym, dlvsym)
82# endif
83#endif
84