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