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 <sys/mman.h> 34 #include <dlfcn.h> 35 #include <link.h> 36 #include <stddef.h> 37 #include "namespace.h" 38 #include <pthread.h> 39 #include "un-namespace.h" 40 #include "libc_private.h" 41 42 static char sorry[] = "Service unavailable"; 43 44 void _rtld_thread_init(void *); 45 void _rtld_atfork_pre(int *); 46 void _rtld_atfork_post(int *); 47 48 /* 49 * For ELF, the dynamic linker directly resolves references to its 50 * services to functions inside the dynamic linker itself. These 51 * weak-symbol stubs are necessary so that "ld" won't complain about 52 * undefined symbols. The stubs are executed only when the program is 53 * linked statically, or when a given service isn't implemented in the 54 * dynamic linker. They must return an error if called, and they must 55 * be weak symbols so that the dynamic linker can override them. 56 */ 57 58 #pragma weak _rtld_error 59 void 60 _rtld_error(const char *fmt, ...) 61 { 62 } 63 64 #pragma weak dladdr 65 int 66 dladdr(const void *addr, Dl_info *dlip) 67 { 68 _rtld_error(sorry); 69 return 0; 70 } 71 72 #pragma weak dlclose 73 int 74 dlclose(void *handle) 75 { 76 _rtld_error(sorry); 77 return -1; 78 } 79 80 #pragma weak dlerror 81 char * 82 dlerror(void) 83 { 84 return sorry; 85 } 86 87 #pragma weak dllockinit 88 void 89 dllockinit(void *context, 90 void *(*lock_create)(void *context), 91 void (*rlock_acquire)(void *lock), 92 void (*wlock_acquire)(void *lock), 93 void (*lock_release)(void *lock), 94 void (*lock_destroy)(void *lock), 95 void (*context_destroy)(void *context)) 96 { 97 if (context_destroy != NULL) 98 context_destroy(context); 99 } 100 101 #pragma weak dlopen 102 void * 103 dlopen(const char *name, int mode) 104 { 105 _rtld_error(sorry); 106 return NULL; 107 } 108 109 #pragma weak dlsym 110 void * 111 dlsym(void * __restrict handle, const char * __restrict name) 112 { 113 _rtld_error(sorry); 114 return NULL; 115 } 116 117 #pragma weak dlfunc 118 dlfunc_t 119 dlfunc(void * __restrict handle, const char * __restrict name) 120 { 121 _rtld_error(sorry); 122 return NULL; 123 } 124 125 #pragma weak dlvsym 126 void * 127 dlvsym(void * __restrict handle, const char * __restrict name, 128 const char * __restrict version) 129 { 130 _rtld_error(sorry); 131 return NULL; 132 } 133 134 #pragma weak dlinfo 135 int 136 dlinfo(void * __restrict handle, int request, void * __restrict p) 137 { 138 _rtld_error(sorry); 139 return 0; 140 } 141 142 #pragma weak _rtld_thread_init 143 void 144 _rtld_thread_init(void * li) 145 { 146 _rtld_error(sorry); 147 } 148 149 static pthread_once_t dl_phdr_info_once = PTHREAD_ONCE_INIT; 150 static struct dl_phdr_info phdr_info; 151 152 static void 153 dl_init_phdr_info(void) 154 { 155 Elf_Auxinfo *auxp; 156 unsigned int i; 157 158 for (auxp = __elf_aux_vector; auxp->a_type != AT_NULL; auxp++) { 159 switch (auxp->a_type) { 160 case AT_BASE: 161 phdr_info.dlpi_addr = (Elf_Addr)auxp->a_un.a_ptr; 162 break; 163 case AT_EXECPATH: 164 phdr_info.dlpi_name = (const char *)auxp->a_un.a_ptr; 165 break; 166 case AT_PHDR: 167 phdr_info.dlpi_phdr = 168 (const Elf_Phdr *)auxp->a_un.a_ptr; 169 break; 170 case AT_PHNUM: 171 phdr_info.dlpi_phnum = (Elf_Half)auxp->a_un.a_val; 172 break; 173 } 174 } 175 for (i = 0; i < phdr_info.dlpi_phnum; i++) { 176 if (phdr_info.dlpi_phdr[i].p_type == PT_TLS) { 177 phdr_info.dlpi_tls_modid = 1; 178 phdr_info.dlpi_tls_data = 179 (void*)phdr_info.dlpi_phdr[i].p_vaddr; 180 } 181 } 182 phdr_info.dlpi_adds = 1; 183 } 184 185 #pragma weak dl_iterate_phdr 186 int 187 dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *), 188 void *data) 189 { 190 191 __init_elf_aux_vector(); 192 if (__elf_aux_vector == NULL) 193 return (1); 194 _once(&dl_phdr_info_once, dl_init_phdr_info); 195 return (callback(&phdr_info, sizeof(phdr_info), data)); 196 } 197 198 #pragma weak fdlopen 199 void * 200 fdlopen(int fd, int mode) 201 { 202 203 _rtld_error(sorry); 204 return NULL; 205 } 206 207 #pragma weak _rtld_atfork_pre 208 void 209 _rtld_atfork_pre(int *locks) 210 { 211 } 212 213 #pragma weak _rtld_atfork_post 214 void 215 _rtld_atfork_post(int *locks) 216 { 217 } 218 219 #pragma weak _rtld_addr_phdr 220 int 221 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 222 { 223 224 return (0); 225 } 226 227 #pragma weak _rtld_get_stack_prot 228 int 229 _rtld_get_stack_prot(void) 230 { 231 232 return (PROT_EXEC | PROT_READ | PROT_WRITE); 233 } 234 235 #pragma weak _rtld_is_dlopened 236 int 237 _rtld_is_dlopened(void *arg) 238 { 239 240 return (0); 241 } 242