Initial import from FreeBSD RELENG_4:
[dragonfly.git] / lib / libc / gen / dlfcn.c
CommitLineData
984263bc
MD
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 * $FreeBSD: src/lib/libc/gen/dlfcn.c,v 1.6.2.1 2003/02/20 20:42:45 kan Exp $
27 */
28
29/*
30 * Linkage to services provided by the dynamic linker. These are
31 * implemented differently in ELF and a.out, because the dynamic
32 * linkers have different interfaces.
33 */
34
35#ifdef __ELF__
36
37#include <dlfcn.h>
38#include <stddef.h>
39
40static const char sorry[] = "Service unavailable";
41
42/*
43 * For ELF, the dynamic linker directly resolves references to its
44 * services to functions inside the dynamic linker itself. These
45 * weak-symbol stubs are necessary so that "ld" won't complain about
46 * undefined symbols. The stubs are executed only when the program is
47 * linked statically, or when a given service isn't implemented in the
48 * dynamic linker. They must return an error if called, and they must
49 * be weak symbols so that the dynamic linker can override them.
50 */
51
52#pragma weak _rtld_error
53void
54_rtld_error(const char *fmt, ...)
55{
56}
57
58#pragma weak dladdr
59int
60dladdr(const void *addr, Dl_info *dlip)
61{
62 _rtld_error(sorry);
63 return 0;
64}
65
66#pragma weak dlclose
67int
68dlclose(void *handle)
69{
70 _rtld_error(sorry);
71 return -1;
72}
73
74#pragma weak dlerror
75const char *
76dlerror(void)
77{
78 return sorry;
79}
80
81#pragma weak dllockinit
82void
83dllockinit(void *context,
84 void *(*lock_create)(void *context),
85 void (*rlock_acquire)(void *lock),
86 void (*wlock_acquire)(void *lock),
87 void (*lock_release)(void *lock),
88 void (*lock_destroy)(void *lock),
89 void (*context_destroy)(void *context))
90{
91 if (context_destroy != NULL)
92 context_destroy(context);
93}
94
95#pragma weak dlopen
96void *
97dlopen(const char *name, int mode)
98{
99 _rtld_error(sorry);
100 return NULL;
101}
102
103#pragma weak dlsym
104void *
105dlsym(void *handle, const char *name)
106{
107 _rtld_error(sorry);
108 return NULL;
109}
110
111#pragma weak dlinfo
112int
113dlinfo(void *handle, int request, void *p)
114{
115 _rtld_error(sorry);
116 return NULL;
117}
118
119#else /* a.out format */
120
121#include <sys/types.h>
122#include <nlist.h> /* XXX - Required by link.h */
123#include <dlfcn.h>
124#include <link.h>
125#include <stddef.h>
126
127/*
128 * For a.out, entry to the dynamic linker is via these trampolines.
129 * They enter the dynamic linker through the ld_entry struct that was
130 * passed back from the dynamic linker at startup time.
131 */
132
133/* GCC is needed because we use its __builtin_return_address construct. */
134
135#ifndef __GNUC__
136#error "GCC is needed to compile this file"
137#endif
138
139/*
140 * These variables are set by code in crt0.o. For compatibility with
141 * old executables, they must be common, not extern.
142 */
143struct ld_entry *__ldso_entry; /* Entry points to dynamic linker */
144int __ldso_version; /* Dynamic linker version number */
145
146int
147dladdr(const void *addr, Dl_info *dlip)
148{
149 if (__ldso_entry == NULL || __ldso_version < LDSO_VERSION_HAS_DLADDR)
150 return 0;
151 return (__ldso_entry->dladdr)(addr, dlip);
152}
153
154int
155dlclose(void *handle)
156{
157 if (__ldso_entry == NULL)
158 return -1;
159 return (__ldso_entry->dlclose)(handle);
160}
161
162const char *
163dlerror(void)
164{
165 if (__ldso_entry == NULL)
166 return "Service unavailable";
167 return (__ldso_entry->dlerror)();
168}
169
170void *
171dlopen(const char *name, int mode)
172{
173 if (__ldso_entry == NULL)
174 return NULL;
175 return (__ldso_entry->dlopen)(name, mode);
176}
177
178void *
179dlsym(void *handle, const char *name)
180{
181 if (__ldso_entry == NULL)
182 return NULL;
183 if (__ldso_version >= LDSO_VERSION_HAS_DLSYM3) {
184 void *retaddr = __builtin_return_address(0); /* __GNUC__ only */
185 return (__ldso_entry->dlsym3)(handle, name, retaddr);
186 } else
187 return (__ldso_entry->dlsym)(handle, name);
188}
189
190#endif /* __ELF__ */