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 * $FreeBSD: src/lib/libc/gen/dlfcn.c 217154 2011-01-08 17:13:43Z kib $ 27 */ 28 29 #include <sys/mman.h> 30 #include <dlfcn.h> 31 #include <link.h> 32 #include <stddef.h> 33 #include <string.h> 34 35 extern char **environ; 36 37 static char sorry[] = "Service unavailable"; 38 39 /* 40 * For ELF, the dynamic linker directly resolves references to its 41 * services to functions inside the dynamic linker itself. These 42 * weak-symbol stubs are necessary so that "ld" won't complain about 43 * undefined symbols. The stubs are executed only when the program is 44 * linked statically, or when a given service isn't implemented in the 45 * dynamic linker. They must return an error if called, and they must 46 * be weak symbols so that the dynamic linker can override them. 47 */ 48 49 #pragma weak _rtld_error 50 void 51 _rtld_error(const char *fmt __unused, ...) 52 { 53 } 54 55 #pragma weak dladdr 56 int 57 dladdr(const void *addr __unused, Dl_info *dlip __unused) 58 { 59 _rtld_error(sorry); 60 return 0; 61 } 62 63 #pragma weak dlclose 64 int 65 dlclose(void *handle __unused) 66 { 67 _rtld_error(sorry); 68 return -1; 69 } 70 71 #pragma weak dlerror 72 char * 73 dlerror(void) 74 { 75 return sorry; 76 } 77 78 #pragma weak dlopen 79 void * 80 dlopen(const char *name __unused, int mode __unused) 81 { 82 _rtld_error(sorry); 83 return NULL; 84 } 85 86 #pragma weak dlsym 87 void * 88 dlsym(void *handle __unused, const char *name __unused) 89 { 90 _rtld_error(sorry); 91 return NULL; 92 } 93 94 #pragma weak dlfunc 95 dlfunc_t 96 dlfunc(void * handle __unused, const char * name __unused) 97 { 98 _rtld_error(sorry); 99 return NULL; 100 } 101 102 #pragma weak dlvsym 103 void * 104 dlvsym(void *handle __unused,const char *name __unused, 105 const char *version __unused) 106 { 107 _rtld_error(sorry); 108 return NULL; 109 } 110 111 #pragma weak _rtld_thread_init 112 void 113 _rtld_thread_init(void * li) 114 { 115 _rtld_error(sorry); 116 } 117 118 #pragma weak dlinfo 119 int 120 dlinfo(void *handle __unused, int request __unused, void *p __unused) 121 { 122 _rtld_error(sorry); 123 return 0; 124 } 125 126 __dso_hidden struct dl_phdr_info 127 build_phdr_info(void) 128 { 129 struct dl_phdr_info phdr_info; 130 Elf_Addr *sp; 131 Elf_Auxinfo *aux, *auxp; 132 unsigned int i; 133 134 sp = (Elf_Addr *) environ; 135 while (*sp++ != 0) 136 ; 137 aux = (Elf_Auxinfo *) sp; 138 memset (&phdr_info, 0, sizeof(phdr_info)); 139 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 140 switch (auxp->a_type) { 141 case AT_BASE: 142 phdr_info.dlpi_addr = (Elf_Addr) auxp->a_un.a_ptr; 143 break; 144 case AT_EXECPATH: 145 phdr_info.dlpi_name = (const char *) auxp->a_un.a_ptr; 146 break; 147 case AT_PHDR: 148 phdr_info.dlpi_phdr = (const Elf_Phdr *) auxp->a_un.a_ptr; 149 break; 150 case AT_PHNUM: 151 phdr_info.dlpi_phnum = (Elf_Half) auxp->a_un.a_val; 152 break; 153 } 154 } 155 156 for (i = 0; i < phdr_info.dlpi_phnum; i++) 157 if (phdr_info.dlpi_phdr[i].p_type == PT_TLS) { 158 phdr_info.dlpi_tls_modid = 1; 159 phdr_info.dlpi_tls_data = 160 (void*)phdr_info.dlpi_phdr[i].p_vaddr; 161 } 162 163 return (phdr_info); 164 } 165 166 #pragma weak dl_iterate_phdr 167 int 168 dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *), 169 void *data) 170 { 171 static int seen = 0; 172 static struct dl_phdr_info phdr_info; 173 if (!seen) { 174 seen = 1; 175 phdr_info = build_phdr_info(); 176 } 177 178 return callback(&phdr_info, sizeof(phdr_info), data); 179 } 180 181 #pragma weak fdlopen 182 void * 183 fdlopen(int fd __unused, int mode __unused) 184 { 185 _rtld_error(sorry); 186 return NULL; 187 } 188 189 #pragma weak _rtld_addr_phdr 190 int 191 _rtld_addr_phdr(const void *addr __unused, 192 struct dl_phdr_info *phdr_info __unused) 193 { 194 195 return (0); 196 } 197 198 #pragma weak _rtld_get_stack_prot 199 int 200 _rtld_get_stack_prot(void) 201 { 202 return (PROT_EXEC | PROT_READ | PROT_WRITE); 203 } 204 205 #pragma weak _rtld_thread_prefork 206 void 207 _rtld_thread_prefork(void) 208 { 209 } 210 211 #pragma weak _rtld_thread_postfork 212 void 213 _rtld_thread_postfork(void) 214 { 215 } 216 217 #pragma weak _rtld_thread_childfork 218 void 219 _rtld_thread_childfork(void) 220 { 221 } 222