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/types.h> 38 #include <sys/mman.h> 39 #include <machine/atomic.h> 40 #include <dlfcn.h> 41 #include <link.h> 42 #include <stddef.h> 43 #include "namespace.h" 44 #include <pthread.h> 45 #include "un-namespace.h" 46 #include "libc_private.h" 47 #include "reentrant.h" 48 49 static char sorry[] = "Service unavailable"; 50 51 void _rtld_thread_init(void *); 52 void _rtld_atfork_pre(int *); 53 void _rtld_atfork_post(int *); 54 55 /* 56 * For ELF, the dynamic linker directly resolves references to its 57 * services to functions inside the dynamic linker itself. These 58 * weak-symbol stubs are necessary so that "ld" won't complain about 59 * undefined symbols. The stubs are executed only when the program is 60 * linked statically, or when a given service isn't implemented in the 61 * dynamic linker. They must return an error if called, and they must 62 * be weak symbols so that the dynamic linker can override them. 63 */ 64 65 #pragma weak _rtld_error 66 void 67 _rtld_error(const char *fmt __unused, ...) 68 { 69 } 70 71 #pragma weak dladdr 72 int 73 dladdr(const void *addr __unused, Dl_info *dlip __unused) 74 { 75 76 _rtld_error(sorry); 77 return (0); 78 } 79 80 #pragma weak dlclose 81 int 82 dlclose(void *handle __unused) 83 { 84 85 _rtld_error(sorry); 86 return (-1); 87 } 88 89 #pragma weak dlerror 90 char * 91 dlerror(void) 92 { 93 94 return (sorry); 95 } 96 97 #pragma weak dllockinit 98 void 99 dllockinit(void *context, 100 void *(*lock_create)(void *context) __unused, 101 void (*rlock_acquire)(void *lock) __unused, 102 void (*wlock_acquire)(void *lock) __unused, 103 void (*lock_release)(void *lock) __unused, 104 void (*lock_destroy)(void *lock) __unused, 105 void (*context_destroy)(void *context) __unused) 106 { 107 108 if (context_destroy != NULL) 109 context_destroy(context); 110 } 111 112 #pragma weak dlopen 113 void * 114 dlopen(const char *name __unused, int mode __unused) 115 { 116 117 _rtld_error(sorry); 118 return (NULL); 119 } 120 121 #pragma weak dlsym 122 void * 123 dlsym(void * __restrict handle __unused, const char * __restrict name __unused) 124 { 125 126 _rtld_error(sorry); 127 return (NULL); 128 } 129 130 #pragma weak dlfunc 131 dlfunc_t 132 dlfunc(void * __restrict handle __unused, const char * __restrict name __unused) 133 { 134 135 _rtld_error(sorry); 136 return (NULL); 137 } 138 139 #pragma weak dlvsym 140 void * 141 dlvsym(void * __restrict handle __unused, const char * __restrict name __unused, 142 const char * __restrict version __unused) 143 { 144 145 _rtld_error(sorry); 146 return (NULL); 147 } 148 149 #pragma weak dlinfo 150 int 151 dlinfo(void * __restrict handle __unused, int request __unused, 152 void * __restrict p __unused) 153 { 154 155 _rtld_error(sorry); 156 return (0); 157 } 158 159 #pragma weak _rtld_thread_init 160 void 161 _rtld_thread_init(void *li __unused) 162 { 163 164 _rtld_error(sorry); 165 } 166 167 #ifndef IN_LIBDL 168 static pthread_once_t dl_phdr_info_once = PTHREAD_ONCE_INIT; 169 static struct dl_phdr_info phdr_info; 170 static mutex_t dl_phdr_info_lock = MUTEX_INITIALIZER; 171 172 static void 173 dl_init_phdr_info(void) 174 { 175 Elf_Auxinfo *auxp; 176 unsigned int i; 177 178 for (auxp = __elf_aux_vector; auxp->a_type != AT_NULL; auxp++) { 179 switch (auxp->a_type) { 180 case AT_BASE: 181 phdr_info.dlpi_addr = (Elf_Addr)auxp->a_un.a_ptr; 182 break; 183 case AT_EXECPATH: 184 phdr_info.dlpi_name = (const char *)auxp->a_un.a_ptr; 185 break; 186 case AT_PHDR: 187 phdr_info.dlpi_phdr = 188 (const Elf_Phdr *)auxp->a_un.a_ptr; 189 break; 190 case AT_PHNUM: 191 phdr_info.dlpi_phnum = (Elf_Half)auxp->a_un.a_val; 192 break; 193 } 194 } 195 for (i = 0; i < phdr_info.dlpi_phnum; i++) { 196 if (phdr_info.dlpi_phdr[i].p_type == PT_TLS) { 197 phdr_info.dlpi_tls_modid = 1; 198 phdr_info.dlpi_tls_data = 199 (void*)phdr_info.dlpi_phdr[i].p_vaddr; 200 } 201 } 202 phdr_info.dlpi_adds = 1; 203 } 204 #endif 205 206 #pragma weak dl_iterate_phdr 207 int 208 dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *) __unused, 209 void *data __unused) 210 { 211 #ifndef IN_LIBDL 212 int ret; 213 214 __init_elf_aux_vector(); 215 if (__elf_aux_vector == NULL) 216 return (1); 217 _once(&dl_phdr_info_once, dl_init_phdr_info); 218 mutex_lock(&dl_phdr_info_lock); 219 ret = callback(&phdr_info, sizeof(phdr_info), data); 220 mutex_unlock(&dl_phdr_info_lock); 221 return (ret); 222 #else 223 return (0); 224 #endif 225 } 226 227 #pragma weak fdlopen 228 void * 229 fdlopen(int fd __unused, int mode __unused) 230 { 231 232 _rtld_error(sorry); 233 return (NULL); 234 } 235 236 #pragma weak _rtld_atfork_pre 237 void 238 _rtld_atfork_pre(int *locks __unused) 239 { 240 } 241 242 #pragma weak _rtld_atfork_post 243 void 244 _rtld_atfork_post(int *locks __unused) 245 { 246 } 247 248 #pragma weak _rtld_addr_phdr 249 int 250 _rtld_addr_phdr(const void *addr __unused, 251 struct dl_phdr_info *phdr_info_a __unused) 252 { 253 254 return (0); 255 } 256 257 #pragma weak _rtld_get_stack_prot 258 int 259 _rtld_get_stack_prot(void) 260 { 261 #ifndef IN_LIBDL 262 unsigned i; 263 int r; 264 static int ret; 265 266 r = atomic_load_int(&ret); 267 if (r != 0) 268 return (r); 269 270 _once(&dl_phdr_info_once, dl_init_phdr_info); 271 r = PROT_EXEC | PROT_READ | PROT_WRITE; 272 for (i = 0; i < phdr_info.dlpi_phnum; i++) { 273 if (phdr_info.dlpi_phdr[i].p_type != PT_GNU_STACK) 274 continue; 275 r = PROT_READ | PROT_WRITE; 276 if ((phdr_info.dlpi_phdr[i].p_flags & PF_X) != 0) 277 r |= PROT_EXEC; 278 break; 279 } 280 atomic_store_int(&ret, r); 281 return (r); 282 #else 283 return (0); 284 #endif 285 } 286 287 #pragma weak _rtld_is_dlopened 288 int 289 _rtld_is_dlopened(void *arg __unused) 290 { 291 292 return (0); 293 } 294 295 #endif /* !defined(IN_LIBDL) || defined(PIC) */ 296