xref: /freebsd/lib/libc/gen/dlfcn.c (revision 7aa383846770374466b1dcb2cefd71bde9acf463)
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("$FreeBSD$");
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 
37 static 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
50 void
51 _rtld_error(const char *fmt, ...)
52 {
53 }
54 
55 #pragma weak dladdr
56 int
57 dladdr(const void *addr, Dl_info *dlip)
58 {
59 	_rtld_error(sorry);
60 	return 0;
61 }
62 
63 #pragma weak dlclose
64 int
65 dlclose(void *handle)
66 {
67 	_rtld_error(sorry);
68 	return -1;
69 }
70 
71 #pragma weak dlerror
72 char *
73 dlerror(void)
74 {
75 	return sorry;
76 }
77 
78 #pragma weak dllockinit
79 void
80 dllockinit(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
93 void *
94 dlopen(const char *name, int mode)
95 {
96 	_rtld_error(sorry);
97 	return NULL;
98 }
99 
100 #pragma weak dlsym
101 void *
102 dlsym(void * __restrict handle, const char * __restrict name)
103 {
104 	_rtld_error(sorry);
105 	return NULL;
106 }
107 
108 #pragma weak dlfunc
109 dlfunc_t
110 dlfunc(void * __restrict handle, const char * __restrict name)
111 {
112 	_rtld_error(sorry);
113 	return NULL;
114 }
115 
116 #pragma weak dlvsym
117 void *
118 dlvsym(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
126 int
127 dlinfo(void * __restrict handle, int request, void * __restrict p)
128 {
129 	_rtld_error(sorry);
130 	return 0;
131 }
132 
133 #pragma weak _rtld_thread_init
134 void
135 _rtld_thread_init(void * li)
136 {
137 	_rtld_error(sorry);
138 }
139 
140 #pragma weak dl_iterate_phdr
141 int
142 dl_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
150 void
151 _rtld_atfork_pre(int *locks)
152 {
153 }
154 
155 #pragma weak _rtld_atfork_post
156 void
157 _rtld_atfork_post(int *locks)
158 {
159 }
160