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 46 static char sorry[] = "Service unavailable"; 47 48 void _rtld_thread_init(void *); 49 void _rtld_atfork_pre(int *); 50 void _rtld_atfork_post(int *); 51 52 /* 53 * For ELF, the dynamic linker directly resolves references to its 54 * services to functions inside the dynamic linker itself. These 55 * weak-symbol stubs are necessary so that "ld" won't complain about 56 * undefined symbols. The stubs are executed only when the program is 57 * linked statically, or when a given service isn't implemented in the 58 * dynamic linker. They must return an error if called, and they must 59 * be weak symbols so that the dynamic linker can override them. 60 */ 61 62 #pragma weak _rtld_error 63 void 64 _rtld_error(const char *fmt __unused, ...) 65 { 66 } 67 68 #pragma weak dladdr 69 int 70 dladdr(const void *addr __unused, Dl_info *dlip __unused) 71 { 72 73 _rtld_error(sorry); 74 return (0); 75 } 76 77 #pragma weak dlclose 78 int 79 dlclose(void *handle __unused) 80 { 81 82 _rtld_error(sorry); 83 return (-1); 84 } 85 86 #pragma weak dlerror 87 char * 88 dlerror(void) 89 { 90 91 return (sorry); 92 } 93 94 #pragma weak dllockinit 95 void 96 dllockinit(void *context, 97 void *(*lock_create)(void *context) __unused, 98 void (*rlock_acquire)(void *lock) __unused, 99 void (*wlock_acquire)(void *lock) __unused, 100 void (*lock_release)(void *lock) __unused, 101 void (*lock_destroy)(void *lock) __unused, 102 void (*context_destroy)(void *context) __unused) 103 { 104 105 if (context_destroy != NULL) 106 context_destroy(context); 107 } 108 109 #pragma weak dlopen 110 void * 111 dlopen(const char *name __unused, int mode __unused) 112 { 113 114 _rtld_error(sorry); 115 return (NULL); 116 } 117 118 #pragma weak dlsym 119 void * 120 dlsym(void * __restrict handle __unused, const char * __restrict name __unused) 121 { 122 123 _rtld_error(sorry); 124 return (NULL); 125 } 126 127 #pragma weak dlfunc 128 dlfunc_t 129 dlfunc(void * __restrict handle __unused, const char * __restrict name __unused) 130 { 131 132 _rtld_error(sorry); 133 return (NULL); 134 } 135 136 #pragma weak dlvsym 137 void * 138 dlvsym(void * __restrict handle __unused, const char * __restrict name __unused, 139 const char * __restrict version __unused) 140 { 141 142 _rtld_error(sorry); 143 return (NULL); 144 } 145 146 #pragma weak dlinfo 147 int 148 dlinfo(void * __restrict handle __unused, int request __unused, 149 void * __restrict p __unused) 150 { 151 152 _rtld_error(sorry); 153 return (0); 154 } 155 156 #pragma weak _rtld_thread_init 157 void 158 _rtld_thread_init(void *li __unused) 159 { 160 161 _rtld_error(sorry); 162 } 163 164 #ifndef IN_LIBDL 165 static pthread_once_t dl_phdr_info_once = PTHREAD_ONCE_INIT; 166 static struct dl_phdr_info phdr_info; 167 168 static void 169 dl_init_phdr_info(void) 170 { 171 Elf_Auxinfo *auxp; 172 unsigned int i; 173 174 for (auxp = __elf_aux_vector; auxp->a_type != AT_NULL; auxp++) { 175 switch (auxp->a_type) { 176 case AT_BASE: 177 phdr_info.dlpi_addr = (Elf_Addr)auxp->a_un.a_ptr; 178 break; 179 case AT_EXECPATH: 180 phdr_info.dlpi_name = (const char *)auxp->a_un.a_ptr; 181 break; 182 case AT_PHDR: 183 phdr_info.dlpi_phdr = 184 (const Elf_Phdr *)auxp->a_un.a_ptr; 185 break; 186 case AT_PHNUM: 187 phdr_info.dlpi_phnum = (Elf_Half)auxp->a_un.a_val; 188 break; 189 } 190 } 191 for (i = 0; i < phdr_info.dlpi_phnum; i++) { 192 if (phdr_info.dlpi_phdr[i].p_type == PT_TLS) { 193 phdr_info.dlpi_tls_modid = 1; 194 phdr_info.dlpi_tls_data = 195 (void*)phdr_info.dlpi_phdr[i].p_vaddr; 196 } 197 } 198 phdr_info.dlpi_adds = 1; 199 } 200 #endif 201 202 #pragma weak dl_iterate_phdr 203 int 204 dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *) __unused, 205 void *data __unused) 206 { 207 208 #ifndef IN_LIBDL 209 __init_elf_aux_vector(); 210 if (__elf_aux_vector == NULL) 211 return (1); 212 _once(&dl_phdr_info_once, dl_init_phdr_info); 213 return (callback(&phdr_info, sizeof(phdr_info), data)); 214 #else 215 return (0); 216 #endif 217 } 218 219 #pragma weak fdlopen 220 void * 221 fdlopen(int fd __unused, int mode __unused) 222 { 223 224 _rtld_error(sorry); 225 return (NULL); 226 } 227 228 #pragma weak _rtld_atfork_pre 229 void 230 _rtld_atfork_pre(int *locks __unused) 231 { 232 } 233 234 #pragma weak _rtld_atfork_post 235 void 236 _rtld_atfork_post(int *locks __unused) 237 { 238 } 239 240 #pragma weak _rtld_addr_phdr 241 int 242 _rtld_addr_phdr(const void *addr __unused, 243 struct dl_phdr_info *phdr_info_a __unused) 244 { 245 246 return (0); 247 } 248 249 #pragma weak _rtld_get_stack_prot 250 int 251 _rtld_get_stack_prot(void) 252 { 253 254 return (PROT_EXEC | PROT_READ | PROT_WRITE); 255 } 256 257 #pragma weak _rtld_is_dlopened 258 int 259 _rtld_is_dlopened(void *arg __unused) 260 { 261 262 return (0); 263 } 264 265 #endif /* !defined(IN_LIBDL) || defined(PIC) */ 266