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 #include <string.h> 34 35 extern char **environ; 36 void _rtld_error(const char *, ...); 37 38 static char sorry[] = "Service unavailable"; 39 40 /* 41 * For ELF, the dynamic linker directly resolves references to its 42 * services to functions inside the dynamic linker itself. These 43 * weak-symbol stubs are necessary so that "ld" won't complain about 44 * undefined symbols. The stubs are executed only when the program is 45 * linked statically, or when a given service isn't implemented in the 46 * dynamic linker. They must return an error if called, and they must 47 * be weak symbols so that the dynamic linker can override them. 48 */ 49 50 #pragma weak _rtld_error 51 void 52 _rtld_error(const char *fmt __unused, ...) 53 { 54 } 55 56 #pragma weak dladdr 57 int 58 dladdr(const void *addr __unused, Dl_info *dlip __unused) 59 { 60 _rtld_error(sorry); 61 return 0; 62 } 63 64 #pragma weak dlclose 65 int 66 dlclose(void *handle __unused) 67 { 68 _rtld_error(sorry); 69 return -1; 70 } 71 72 #pragma weak dlerror 73 char * 74 dlerror(void) 75 { 76 return sorry; 77 } 78 79 #pragma weak dlopen 80 void * 81 dlopen(const char *name __unused, int mode __unused) 82 { 83 _rtld_error(sorry); 84 return NULL; 85 } 86 87 #pragma weak dlsym 88 void * 89 dlsym(void *handle __unused, const char *name __unused) 90 { 91 _rtld_error(sorry); 92 return NULL; 93 } 94 95 #pragma weak dlfunc 96 dlfunc_t 97 dlfunc(void * handle __unused, const char * name __unused) 98 { 99 _rtld_error(sorry); 100 return NULL; 101 } 102 103 #pragma weak dlvsym 104 void * 105 dlvsym(void *handle __unused,const char *name __unused, 106 const char *version __unused) 107 { 108 _rtld_error(sorry); 109 return NULL; 110 } 111 112 #pragma weak dlinfo 113 int 114 dlinfo(void *handle __unused, int request __unused, void *p __unused) 115 { 116 _rtld_error(sorry); 117 return 0; 118 } 119 120 __dso_hidden struct dl_phdr_info 121 build_phdr_info(void) 122 { 123 struct dl_phdr_info phdr_info; 124 Elf_Addr *sp; 125 Elf_Auxinfo *aux, *auxp; 126 unsigned int i; 127 128 sp = (Elf_Addr *) environ; 129 while (*sp++ != 0) 130 ; 131 aux = (Elf_Auxinfo *) sp; 132 memset (&phdr_info, 0, sizeof(phdr_info)); 133 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 134 switch (auxp->a_type) { 135 case AT_BASE: 136 phdr_info.dlpi_addr = (Elf_Addr) auxp->a_un.a_ptr; 137 break; 138 139 case AT_EXECPATH: 140 phdr_info.dlpi_name = (const char *) auxp->a_un.a_ptr; 141 break; 142 143 case AT_PHDR: 144 phdr_info.dlpi_phdr = (const Elf_Phdr *) auxp->a_un.a_ptr; 145 break; 146 147 case AT_PHNUM: 148 phdr_info.dlpi_phnum = (Elf_Half) auxp->a_un.a_val; 149 break; 150 } 151 } 152 153 for (i = 0; i < phdr_info.dlpi_phnum; i++) 154 if (phdr_info.dlpi_phdr[i].p_type == PT_TLS) { 155 phdr_info.dlpi_tls_modid = 1; 156 phdr_info.dlpi_tls_data = 157 (void*) phdr_info.dlpi_phdr[i].p_vaddr; 158 } 159 160 return (phdr_info); 161 } 162 163 #pragma weak dl_iterate_phdr 164 int 165 dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *), 166 void *data) 167 { 168 static int seen = 0; 169 static struct dl_phdr_info phdr_info; 170 if (!seen) { 171 seen = 1; 172 phdr_info = build_phdr_info(); 173 } 174 175 return callback(&phdr_info, sizeof(phdr_info), data); 176 } 177 178 #pragma weak fdlopen 179 void * 180 fdlopen(int fd __unused, int mode __unused) 181 { 182 _rtld_error(sorry); 183 return NULL; 184 } 185 186 #pragma weak _rtld_addr_phdr 187 int 188 _rtld_addr_phdr(const void *addr __unused, 189 struct dl_phdr_info *phdr_info __unused) 190 { 191 192 return (0); 193 } 194 195 #pragma weak _rtld_get_stack_prot 196 int 197 _rtld_get_stack_prot(void) 198 { 199 return (PROT_EXEC | PROT_READ | PROT_WRITE); 200 } 201