| 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 | #include "libc_private.h" |
| 35 | |
| 36 | struct dl_phdr_info build_phdr_info(void); |
| 37 | void _rtld_thread_childfork(void); |
| 38 | void _rtld_thread_init(void *); |
| 39 | void _rtld_thread_postfork(void); |
| 40 | void _rtld_thread_prefork(void); |
| 41 | |
| 42 | extern char **environ; |
| 43 | |
| 44 | static char sorry[] = "Service unavailable"; |
| 45 | |
| 46 | /* |
| 47 | * For ELF, the dynamic linker directly resolves references to its |
| 48 | * services to functions inside the dynamic linker itself. These |
| 49 | * weak-symbol stubs are necessary so that "ld" won't complain about |
| 50 | * undefined symbols. The stubs are executed only when the program is |
| 51 | * linked statically, or when a given service isn't implemented in the |
| 52 | * dynamic linker. They must return an error if called, and they must |
| 53 | * be weak symbols so that the dynamic linker can override them. |
| 54 | */ |
| 55 | |
| 56 | #pragma weak _rtld_error |
| 57 | void |
| 58 | _rtld_error(const char *fmt __unused, ...) |
| 59 | { |
| 60 | } |
| 61 | |
| 62 | #pragma weak dladdr |
| 63 | int |
| 64 | dladdr(const void *addr __unused, Dl_info *dlip __unused) |
| 65 | { |
| 66 | _rtld_error(sorry); |
| 67 | return 0; |
| 68 | } |
| 69 | |
| 70 | #pragma weak dlclose |
| 71 | int |
| 72 | dlclose(void *handle __unused) |
| 73 | { |
| 74 | _rtld_error(sorry); |
| 75 | return -1; |
| 76 | } |
| 77 | |
| 78 | #pragma weak dlerror |
| 79 | char * |
| 80 | dlerror(void) |
| 81 | { |
| 82 | return sorry; |
| 83 | } |
| 84 | |
| 85 | #pragma weak dlopen |
| 86 | void * |
| 87 | dlopen(const char *name __unused, int mode __unused) |
| 88 | { |
| 89 | _rtld_error(sorry); |
| 90 | return NULL; |
| 91 | } |
| 92 | |
| 93 | #pragma weak dlsym |
| 94 | void * |
| 95 | dlsym(void *handle __unused, const char *name __unused) |
| 96 | { |
| 97 | _rtld_error(sorry); |
| 98 | return NULL; |
| 99 | } |
| 100 | |
| 101 | #pragma weak dlfunc |
| 102 | dlfunc_t |
| 103 | dlfunc(void * handle __unused, const char * name __unused) |
| 104 | { |
| 105 | _rtld_error(sorry); |
| 106 | return NULL; |
| 107 | } |
| 108 | |
| 109 | #pragma weak dlvsym |
| 110 | void * |
| 111 | dlvsym(void *handle __unused,const char *name __unused, |
| 112 | const char *version __unused) |
| 113 | { |
| 114 | _rtld_error(sorry); |
| 115 | return NULL; |
| 116 | } |
| 117 | |
| 118 | #pragma weak _rtld_thread_init |
| 119 | void |
| 120 | _rtld_thread_init(void * li __unused) |
| 121 | { |
| 122 | _rtld_error(sorry); |
| 123 | } |
| 124 | |
| 125 | #pragma weak dlinfo |
| 126 | int |
| 127 | dlinfo(void *handle __unused, int request __unused, void *p __unused) |
| 128 | { |
| 129 | _rtld_error(sorry); |
| 130 | return 0; |
| 131 | } |
| 132 | |
| 133 | __dso_hidden struct dl_phdr_info |
| 134 | build_phdr_info(void) |
| 135 | { |
| 136 | struct dl_phdr_info phdr_info; |
| 137 | Elf_Addr *sp; |
| 138 | Elf_Auxinfo *aux, *auxp; |
| 139 | unsigned int i; |
| 140 | |
| 141 | sp = (Elf_Addr *) environ; |
| 142 | while (*sp++ != 0) |
| 143 | ; |
| 144 | aux = (Elf_Auxinfo *) sp; |
| 145 | memset (&phdr_info, 0, sizeof(phdr_info)); |
| 146 | for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { |
| 147 | switch (auxp->a_type) { |
| 148 | case AT_BASE: |
| 149 | phdr_info.dlpi_addr = (Elf_Addr) auxp->a_un.a_ptr; |
| 150 | break; |
| 151 | case AT_EXECPATH: |
| 152 | phdr_info.dlpi_name = (const char *) auxp->a_un.a_ptr; |
| 153 | break; |
| 154 | case AT_PHDR: |
| 155 | phdr_info.dlpi_phdr = (const Elf_Phdr *) auxp->a_un.a_ptr; |
| 156 | break; |
| 157 | case AT_PHNUM: |
| 158 | phdr_info.dlpi_phnum = (Elf_Half) auxp->a_un.a_val; |
| 159 | break; |
| 160 | } |
| 161 | } |
| 162 | |
| 163 | for (i = 0; i < phdr_info.dlpi_phnum; i++) |
| 164 | if (phdr_info.dlpi_phdr[i].p_type == PT_TLS) { |
| 165 | phdr_info.dlpi_tls_modid = 1; |
| 166 | phdr_info.dlpi_tls_data = |
| 167 | (void*)phdr_info.dlpi_phdr[i].p_vaddr; |
| 168 | } |
| 169 | |
| 170 | return (phdr_info); |
| 171 | } |
| 172 | |
| 173 | #pragma weak dl_iterate_phdr |
| 174 | int |
| 175 | dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *), |
| 176 | void *data) |
| 177 | { |
| 178 | static int seen = 0; |
| 179 | static struct dl_phdr_info phdr_info; |
| 180 | if (!seen) { |
| 181 | seen = 1; |
| 182 | phdr_info = build_phdr_info(); |
| 183 | } |
| 184 | |
| 185 | return callback(&phdr_info, sizeof(phdr_info), data); |
| 186 | } |
| 187 | |
| 188 | #pragma weak fdlopen |
| 189 | void * |
| 190 | fdlopen(int fd __unused, int mode __unused) |
| 191 | { |
| 192 | _rtld_error(sorry); |
| 193 | return NULL; |
| 194 | } |
| 195 | |
| 196 | #pragma weak _rtld_addr_phdr |
| 197 | int |
| 198 | _rtld_addr_phdr(const void *addr __unused, |
| 199 | struct dl_phdr_info *phdr_info __unused) |
| 200 | { |
| 201 | |
| 202 | return (0); |
| 203 | } |
| 204 | |
| 205 | #pragma weak _rtld_get_stack_prot |
| 206 | int |
| 207 | _rtld_get_stack_prot(void) |
| 208 | { |
| 209 | return (PROT_EXEC | PROT_READ | PROT_WRITE); |
| 210 | } |
| 211 | |
| 212 | #pragma weak _rtld_thread_prefork |
| 213 | void |
| 214 | _rtld_thread_prefork(void) |
| 215 | { |
| 216 | } |
| 217 | |
| 218 | #pragma weak _rtld_thread_postfork |
| 219 | void |
| 220 | _rtld_thread_postfork(void) |
| 221 | { |
| 222 | } |
| 223 | |
| 224 | #pragma weak _rtld_thread_childfork |
| 225 | void |
| 226 | _rtld_thread_childfork(void) |
| 227 | { |
| 228 | } |