dlfcn.c revision 225736 
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: stable/9/lib/libc/gen/dlfcn.c 217154 2011-01-08 17:13:43Z kib $");
29
30/*
31 * Linkage to services provided by the dynamic linker.
32 */
33#include <sys/mman.h>
34#include <dlfcn.h>
35#include <link.h>
36#include <stddef.h>
37
38static char sorry[] = "Service unavailable";
39
40/*
41 * For ELF, the dynamic linker directly resolves references to its
42 * services to functions inside the dynamic linker itself.  These
43 * weak-symbol stubs are necessary so that "ld" won't complain about
44 * undefined symbols.  The stubs are executed only when the program is
45 * linked statically, or when a given service isn't implemented in the
46 * dynamic linker.  They must return an error if called, and they must
47 * be weak symbols so that the dynamic linker can override them.
48 */
49
50#pragma weak _rtld_error
51void
52_rtld_error(const char *fmt, ...)
53{
54}
55
56#pragma weak dladdr
57int
58dladdr(const void *addr, Dl_info *dlip)
59{
60	_rtld_error(sorry);
61	return 0;
62}
63
64#pragma weak dlclose
65int
66dlclose(void *handle)
67{
68	_rtld_error(sorry);
69	return -1;
70}
71
72#pragma weak dlerror
73char *
74dlerror(void)
75{
76	return sorry;
77}
78
79#pragma weak dllockinit
80void
81dllockinit(void *context,
82	   void *(*lock_create)(void *context),
83	   void (*rlock_acquire)(void *lock),
84	   void (*wlock_acquire)(void *lock),
85	   void (*lock_release)(void *lock),
86	   void (*lock_destroy)(void *lock),
87	   void (*context_destroy)(void *context))
88{
89	if (context_destroy != NULL)
90		context_destroy(context);
91}
92
93#pragma weak dlopen
94void *
95dlopen(const char *name, int mode)
96{
97	_rtld_error(sorry);
98	return NULL;
99}
100
101#pragma weak dlsym
102void *
103dlsym(void * __restrict handle, const char * __restrict name)
104{
105	_rtld_error(sorry);
106	return NULL;
107}
108
109#pragma weak dlfunc
110dlfunc_t
111dlfunc(void * __restrict handle, const char * __restrict name)
112{
113	_rtld_error(sorry);
114	return NULL;
115}
116
117#pragma weak dlvsym
118void *
119dlvsym(void * __restrict handle, const char * __restrict name,
120    const char * __restrict version)
121{
122	_rtld_error(sorry);
123	return NULL;
124}
125
126#pragma weak dlinfo
127int
128dlinfo(void * __restrict handle, int request, void * __restrict p)
129{
130	_rtld_error(sorry);
131	return 0;
132}
133
134#pragma weak _rtld_thread_init
135void
136_rtld_thread_init(void * li)
137{
138	_rtld_error(sorry);
139}
140
141#pragma weak dl_iterate_phdr
142int
143dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *),
144    void *data)
145{
146	_rtld_error(sorry);
147	return 0;
148}
149
150#pragma weak _rtld_atfork_pre
151void
152_rtld_atfork_pre(int *locks)
153{
154}
155
156#pragma weak _rtld_atfork_post
157void
158_rtld_atfork_post(int *locks)
159{
160}
161
162#pragma weak _rtld_addr_phdr
163int
164_rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
165{
166
167	return (0);
168}
169
170#pragma weak _rtld_get_stack_prot
171int
172_rtld_get_stack_prot(void)
173{
174
175	return (PROT_EXEC | PROT_READ | PROT_WRITE);
176}
177
178