1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 1998 John D. Polstra 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #if !defined(IN_LIBDL) || defined(PIC) 33 34 /* 35 * Linkage to services provided by the dynamic linker. 36 */ 37 #include <sys/mman.h> 38 #include <dlfcn.h> 39 #include <link.h> 40 #include <stddef.h> 41 #include "namespace.h" 42 #include <pthread.h> 43 #include "un-namespace.h" 44 #include "libc_private.h" 45 #include "reentrant.h" 46 47 static char sorry[] = "Service unavailable"; 48 49 void _rtld_thread_init(void *); 50 void _rtld_atfork_pre(int *); 51 void _rtld_atfork_post(int *); 52 53 /* 54 * For ELF, the dynamic linker directly resolves references to its 55 * services to functions inside the dynamic linker itself. These 56 * weak-symbol stubs are necessary so that "ld" won't complain about 57 * undefined symbols. The stubs are executed only when the program is 58 * linked statically, or when a given service isn't implemented in the 59 * dynamic linker. They must return an error if called, and they must 60 * be weak symbols so that the dynamic linker can override them. 61 */ 62 63 #pragma weak _rtld_error 64 void 65 _rtld_error(const char *fmt __unused, ...) 66 { 67 } 68 69 #pragma weak dladdr 70 int 71 dladdr(const void *addr __unused, Dl_info *dlip __unused) 72 { 73 74 _rtld_error(sorry); 75 return (0); 76 } 77 78 #pragma weak dlclose 79 int 80 dlclose(void *handle __unused) 81 { 82 83 _rtld_error(sorry); 84 return (-1); 85 } 86 87 #pragma weak dlerror 88 char * 89 dlerror(void) 90 { 91 92 return (sorry); 93 } 94 95 #pragma weak dllockinit 96 void 97 dllockinit(void *context, 98 void *(*lock_create)(void *context) __unused, 99 void (*rlock_acquire)(void *lock) __unused, 100 void (*wlock_acquire)(void *lock) __unused, 101 void (*lock_release)(void *lock) __unused, 102 void (*lock_destroy)(void *lock) __unused, 103 void (*context_destroy)(void *context) __unused) 104 { 105 106 if (context_destroy != NULL) 107 context_destroy(context); 108 } 109 110 #pragma weak dlopen 111 void * 112 dlopen(const char *name __unused, int mode __unused) 113 { 114 115 _rtld_error(sorry); 116 return (NULL); 117 } 118 119 #pragma weak dlsym 120 void * 121 dlsym(void * __restrict handle __unused, const char * __restrict name __unused) 122 { 123 124 _rtld_error(sorry); 125 return (NULL); 126 } 127 128 #pragma weak dlfunc 129 dlfunc_t 130 dlfunc(void * __restrict handle __unused, const char * __restrict name __unused) 131 { 132 133 _rtld_error(sorry); 134 return (NULL); 135 } 136 137 #pragma weak dlvsym 138 void * 139 dlvsym(void * __restrict handle __unused, const char * __restrict name __unused, 140 const char * __restrict version __unused) 141 { 142 143 _rtld_error(sorry); 144 return (NULL); 145 } 146 147 #pragma weak dlinfo 148 int 149 dlinfo(void * __restrict handle __unused, int request __unused, 150 void * __restrict p __unused) 151 { 152 153 _rtld_error(sorry); 154 return (0); 155 } 156 157 #pragma weak _rtld_thread_init 158 void 159 _rtld_thread_init(void *li __unused) 160 { 161 162 _rtld_error(sorry); 163 } 164 165 #ifndef IN_LIBDL 166 static pthread_once_t dl_phdr_info_once = PTHREAD_ONCE_INIT; 167 static struct dl_phdr_info phdr_info; 168 static mutex_t dl_phdr_info_lock = MUTEX_INITIALIZER; 169 170 static void 171 dl_init_phdr_info(void) 172 { 173 Elf_Auxinfo *auxp; 174 unsigned int i; 175 176 for (auxp = __elf_aux_vector; auxp->a_type != AT_NULL; auxp++) { 177 switch (auxp->a_type) { 178 case AT_BASE: 179 phdr_info.dlpi_addr = (Elf_Addr)auxp->a_un.a_ptr; 180 break; 181 case AT_EXECPATH: 182 phdr_info.dlpi_name = (const char *)auxp->a_un.a_ptr; 183 break; 184 case AT_PHDR: 185 phdr_info.dlpi_phdr = 186 (const Elf_Phdr *)auxp->a_un.a_ptr; 187 break; 188 case AT_PHNUM: 189 phdr_info.dlpi_phnum = (Elf_Half)auxp->a_un.a_val; 190 break; 191 } 192 } 193 for (i = 0; i < phdr_info.dlpi_phnum; i++) { 194 if (phdr_info.dlpi_phdr[i].p_type == PT_TLS) { 195 phdr_info.dlpi_tls_modid = 1; 196 phdr_info.dlpi_tls_data = 197 (void*)phdr_info.dlpi_phdr[i].p_vaddr; 198 } 199 } 200 phdr_info.dlpi_adds = 1; 201 } 202 #endif 203 204 #pragma weak dl_iterate_phdr 205 int 206 dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *) __unused, 207 void *data __unused) 208 { 209 #ifndef IN_LIBDL 210 int ret; 211 212 __init_elf_aux_vector(); 213 if (__elf_aux_vector == NULL) 214 return (1); 215 _once(&dl_phdr_info_once, dl_init_phdr_info); 216 mutex_lock(&dl_phdr_info_lock); 217 ret = callback(&phdr_info, sizeof(phdr_info), data); 218 mutex_unlock(&dl_phdr_info_lock); 219 return (ret); 220 #else 221 return (0); 222 #endif 223 } 224 225 #pragma weak fdlopen 226 void * 227 fdlopen(int fd __unused, int mode __unused) 228 { 229 230 _rtld_error(sorry); 231 return (NULL); 232 } 233 234 #pragma weak _rtld_atfork_pre 235 void 236 _rtld_atfork_pre(int *locks __unused) 237 { 238 } 239 240 #pragma weak _rtld_atfork_post 241 void 242 _rtld_atfork_post(int *locks __unused) 243 { 244 } 245 246 #pragma weak _rtld_addr_phdr 247 int 248 _rtld_addr_phdr(const void *addr __unused, 249 struct dl_phdr_info *phdr_info_a __unused) 250 { 251 252 return (0); 253 } 254 255 #pragma weak _rtld_get_stack_prot 256 int 257 _rtld_get_stack_prot(void) 258 { 259 260 return (PROT_EXEC | PROT_READ | PROT_WRITE); 261 } 262 263 #pragma weak _rtld_is_dlopened 264 int 265 _rtld_is_dlopened(void *arg __unused) 266 { 267 268 return (0); 269 } 270 271 #endif /* !defined(IN_LIBDL) || defined(PIC) */ 272