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 217154 2011-01-08 17:13:43Z kib $ 27 */ 28 29 #include <sys/mman.h> 30 #include <dlfcn.h> 31 #include <link.h> 32 #include <stddef.h> 33 34 void _rtld_error(const char *, ...); 35 36 static 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 __unused, ...) 51 { 52 } 53 54 #pragma weak dladdr 55 int 56 dladdr(const void *addr __unused, Dl_info *dlip __unused) 57 { 58 _rtld_error(sorry); 59 return 0; 60 } 61 62 #pragma weak dlclose 63 int 64 dlclose(void *handle __unused) 65 { 66 _rtld_error(sorry); 67 return -1; 68 } 69 70 #pragma weak dlerror 71 char * 72 dlerror(void) 73 { 74 return sorry; 75 } 76 77 #pragma weak dlopen 78 void * 79 dlopen(const char *name __unused, int mode __unused) 80 { 81 _rtld_error(sorry); 82 return NULL; 83 } 84 85 #pragma weak dlsym 86 void * 87 dlsym(void *handle __unused, const char *name __unused) 88 { 89 _rtld_error(sorry); 90 return NULL; 91 } 92 93 #pragma weak dlfunc 94 dlfunc_t 95 dlfunc(void * handle __unused, const char * name __unused) 96 { 97 _rtld_error(sorry); 98 return NULL; 99 } 100 101 #pragma weak dlvsym 102 void * 103 dlvsym(void *handle __unused,const char *name __unused, 104 const char *version __unused) 105 { 106 _rtld_error(sorry); 107 return NULL; 108 } 109 110 #pragma weak dlinfo 111 int 112 dlinfo(void *handle __unused, int request __unused, void *p __unused) 113 { 114 _rtld_error(sorry); 115 return 0; 116 } 117 118 #pragma weak dl_iterate_phdr 119 int 120 dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *), 121 void *data) 122 { 123 _rtld_error(sorry); 124 return 0; 125 } 126 127 #pragma weak _rtld_addr_phdr 128 int 129 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 130 { 131 132 return (0); 133 } 134 135 #pragma weak _rtld_get_stack_prot 136 int 137 _rtld_get_stack_prot(void) 138 { 139 return (PROT_EXEC | PROT_READ | PROT_WRITE); 140 } 141