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 34 extern char **environ; 35 void _rtld_error(const char *, ...); 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 dlinfo 112 int 113 dlinfo(void *handle __unused, int request __unused, void *p __unused) 114 { 115 _rtld_error(sorry); 116 return 0; 117 } 118 119 __dso_hidden struct dl_phdr_info 120 build_phdr_info(void) 121 { 122 struct dl_phdr_info phdr_info; 123 Elf_Addr *sp; 124 Elf_Auxinfo *aux, *auxp; 125 unsigned int i; 126 127 sp = (Elf_Addr *) environ; 128 while (*sp++ != 0) 129 ; 130 aux = (Elf_Auxinfo *) sp; 131 memset (&phdr_info, 0, sizeof(phdr_info)); 132 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 133 switch (auxp->a_type) { 134 case AT_BASE: 135 phdr_info.dlpi_addr = (Elf_Addr) auxp->a_un.a_ptr; 136 break; 137 138 case AT_EXECPATH: 139 phdr_info.dlpi_name = (const char *) auxp->a_un.a_ptr; 140 break; 141 142 case AT_PHDR: 143 phdr_info.dlpi_phdr = (const Elf_Phdr *) auxp->a_un.a_ptr; 144 break; 145 146 case AT_PHNUM: 147 phdr_info.dlpi_phnum = (Elf_Half) auxp->a_un.a_val; 148 break; 149 } 150 } 151 152 for (i = 0; i < phdr_info.dlpi_phnum; i++) 153 if (phdr_info.dlpi_phdr[i].p_type == PT_TLS) { 154 phdr_info.dlpi_tls_modid = 1; 155 phdr_info.dlpi_tls_data = 156 (void*) phdr_info.dlpi_phdr[i].p_vaddr; 157 } 158 159 return (phdr_info); 160 } 161 162 #pragma weak dl_iterate_phdr 163 int 164 dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *), 165 void *data) 166 { 167 static seen = 0; 168 static struct dl_phdr_info phdr_info; 169 if (!seen) { 170 seen = 1; 171 phdr_info = build_phdr_info(); 172 } 173 174 return callback(&phdr_info, sizeof(phdr_info), data); 175 } 176 177 #pragma weak fdlopen 178 void * 179 fdlopen(int fd, int mode) 180 { 181 _rtld_error(sorry); 182 return NULL; 183 } 184 185 #pragma weak _rtld_addr_phdr 186 int 187 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 188 { 189 190 return (0); 191 } 192 193 #pragma weak _rtld_get_stack_prot 194 int 195 _rtld_get_stack_prot(void) 196 { 197 return (PROT_EXEC | PROT_READ | PROT_WRITE); 198 } 199