dlfcn.c revision 205606 
1/*-
2 * Copyright (c) 1998 John D. Polstra
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: head/lib/libc/gen/dlfcn.c 205606 2010-03-24 15:59:51Z gahr $");
29
30/*
31 * Linkage to services provided by the dynamic linker.
32 */
33#include <dlfcn.h>
34#include <link.h>
35#include <stddef.h>
36
37static char sorry[] = "Service unavailable";
38
39/*
40 * For ELF, the dynamic linker directly resolves references to its
41 * services to functions inside the dynamic linker itself.  These
42 * weak-symbol stubs are necessary so that "ld" won't complain about
43 * undefined symbols.  The stubs are executed only when the program is
44 * linked statically, or when a given service isn't implemented in the
45 * dynamic linker.  They must return an error if called, and they must
46 * be weak symbols so that the dynamic linker can override them.
47 */
48
49#pragma weak _rtld_error
50void
51_rtld_error(const char *fmt, ...)
52{
53}
54
55#pragma weak dladdr
56int
57dladdr(const void *addr, Dl_info *dlip)
58{
59	_rtld_error(sorry);
60	return 0;
61}
62
63#pragma weak dlclose
64int
65dlclose(void *handle)
66{
67	_rtld_error(sorry);
68	return -1;
69}
70
71#pragma weak dlerror
72char *
73dlerror(void)
74{
75	return sorry;
76}
77
78#pragma weak dllockinit
79void
80dllockinit(void *context,
81	   void *(*lock_create)(void *context),
82	   void (*rlock_acquire)(void *lock),
83	   void (*wlock_acquire)(void *lock),
84	   void (*lock_release)(void *lock),
85	   void (*lock_destroy)(void *lock),
86	   void (*context_destroy)(void *context))
87{
88	if (context_destroy != NULL)
89		context_destroy(context);
90}
91
92#pragma weak dlopen
93void *
94dlopen(const char *name, int mode)
95{
96	_rtld_error(sorry);
97	return NULL;
98}
99
100#pragma weak dlsym
101void *
102dlsym(void * __restrict handle, const char * __restrict name)
103{
104	_rtld_error(sorry);
105	return NULL;
106}
107
108#pragma weak dlfunc
109dlfunc_t
110dlfunc(void * __restrict handle, const char * __restrict name)
111{
112	_rtld_error(sorry);
113	return NULL;
114}
115
116#pragma weak dlvsym
117void *
118dlvsym(void * __restrict handle, const char * __restrict name,
119    const char * __restrict version)
120{
121	_rtld_error(sorry);
122	return NULL;
123}
124
125#pragma weak dlinfo
126int
127dlinfo(void * __restrict handle, int request, void * __restrict p)
128{
129	_rtld_error(sorry);
130	return 0;
131}
132
133#pragma weak _rtld_thread_init
134void
135_rtld_thread_init(void * li)
136{
137	_rtld_error(sorry);
138}
139
140#pragma weak dl_iterate_phdr
141int
142dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *),
143    void *data)
144{
145	_rtld_error(sorry);
146	return 0;
147}
148
149#pragma weak _rtld_atfork_pre
150void
151_rtld_atfork_pre(int *locks)
152{
153}
154
155#pragma weak _rtld_atfork_post
156void
157_rtld_atfork_post(int *locks)
158{
159}
160