lib/libc/gen/dlfcn.c

   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  * $DragonFly: src/lib/libc/gen/dlfcn.c,v 1.4 2005/04/27 11:57:57 joerg Exp $
  28  */
  29
  30 #include <dlfcn.h>
  31 #include <stddef.h>
  32
  33 void    _rtld_error(const char *, ...);
  34
  35 static const char sorry[] = "Service unavailable";
  36
  37 /*
  38  * For ELF, the dynamic linker directly resolves references to its
  39  * services to functions inside the dynamic linker itself.  These
  40  * weak-symbol stubs are necessary so that "ld" won't complain about
  41  * undefined symbols.  The stubs are executed only when the program is
  42  * linked statically, or when a given service isn't implemented in the
  43  * dynamic linker.  They must return an error if called, and they must
  44  * be weak symbols so that the dynamic linker can override them.
  45  */
  46
  47 #pragma weak _rtld_error
  48 void
  49 _rtld_error(const char *fmt __unused, ...)
  50 {
  51 }
  52
  53 #pragma weak dladdr
  54 int
  55 dladdr(const void *addr __unused, Dl_info *dlip __unused)
  56 {
  57         _rtld_error(sorry);
  58         return 0;
  59 }
  60
  61 #pragma weak dlclose
  62 int
  63 dlclose(void *handle __unused)
  64 {
  65         _rtld_error(sorry);
  66         return -1;
  67 }
  68
  69 #pragma weak dlerror
  70 const char *
  71 dlerror(void)
  72 {
  73         return sorry;
  74 }
  75
  76 #pragma weak dlopen
  77 void *
  78 dlopen(const char *name __unused, int mode __unused)
  79 {
  80         _rtld_error(sorry);
  81         return NULL;
  82 }
  83
  84 #pragma weak dlsym
  85 void *
  86 dlsym(void *handle __unused, const char *name __unused)
  87 {
  88         _rtld_error(sorry);
  89         return NULL;
  90 }
  91
  92 #pragma weak dlinfo
  93 int
  94 dlinfo(void *handle __unused, int request __unused, void *p __unused)
  95 {
  96         _rtld_error(sorry);
  97         return NULL;
  98 }