xref: /freebsd/lib/libc/gen/dlfcn.c (revision 2546665afcaf0d53dc2c7058fee96354b3680f5a)
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 <stddef.h>
35 
36 static const char sorry[] = "Service unavailable";
37 
38 /*
39  * For ELF, the dynamic linker directly resolves references to its
40  * services to functions inside the dynamic linker itself.  These
41  * weak-symbol stubs are necessary so that "ld" won't complain about
42  * undefined symbols.  The stubs are executed only when the program is
43  * linked statically, or when a given service isn't implemented in the
44  * dynamic linker.  They must return an error if called, and they must
45  * be weak symbols so that the dynamic linker can override them.
46  */
47 
48 #pragma weak _rtld_error
49 void
50 _rtld_error(const char *fmt, ...)
51 {
52 }
53 
54 #pragma weak dladdr
55 int
56 dladdr(const void *addr, Dl_info *dlip)
57 {
58 	_rtld_error(sorry);
59 	return 0;
60 }
61 
62 #pragma weak dlclose
63 int
64 dlclose(void *handle)
65 {
66 	_rtld_error(sorry);
67 	return -1;
68 }
69 
70 #pragma weak dlerror
71 const char *
72 dlerror(void)
73 {
74 	return sorry;
75 }
76 
77 #pragma weak dllockinit
78 void
79 dllockinit(void *context,
80 	   void *(*lock_create)(void *context),
81 	   void (*rlock_acquire)(void *lock),
82 	   void (*wlock_acquire)(void *lock),
83 	   void (*lock_release)(void *lock),
84 	   void (*lock_destroy)(void *lock),
85 	   void (*context_destroy)(void *context))
86 {
87 	if (context_destroy != NULL)
88 		context_destroy(context);
89 }
90 
91 #pragma weak dlopen
92 void *
93 dlopen(const char *name, int mode)
94 {
95 	_rtld_error(sorry);
96 	return NULL;
97 }
98 
99 #pragma weak dlsym
100 void *
101 dlsym(void * __restrict handle, const char * __restrict name)
102 {
103 	_rtld_error(sorry);
104 	return NULL;
105 }
106 
107 #pragma weak dlinfo
108 int
109 dlinfo(void * __restrict handle, int request, void * __restrict p)
110 {
111 	_rtld_error(sorry);
112 	return 0;
113 }
114 
115 #pragma weak _rtld_thread_init
116 void
117 _rtld_thread_init(void * li)
118 {
119 	_rtld_error(sorry);
120 }
121