1 /* 2 * Copyright (C) 2007 The Android Open Source Project 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 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in 12 * the documentation and/or other materials provided with the 13 * distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include "linker.h" 30 #include "linker_cfi.h" 31 #include "linker_globals.h" 32 #include "linker_dlwarning.h" 33 34 #include <pthread.h> 35 #include <stdio.h> 36 #include <stdlib.h> 37 #include <string.h> 38 #include <android/api-level.h> 39 40 #include <bionic/pthread_internal.h> 41 #include "private/bionic_tls.h" 42 #include "private/ScopedPthreadMutexLocker.h" 43 44 static pthread_mutex_t g_dl_mutex = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP; 45 46 static char* __bionic_set_dlerror(char* new_value) { 47 char** dlerror_slot = &reinterpret_cast<char**>(__get_tls())[TLS_SLOT_DLERROR]; 48 49 char* old_value = *dlerror_slot; 50 *dlerror_slot = new_value; 51 LD_LOG(kLogErrors, "%s\n", new_value); 52 return old_value; 53 } 54 55 static void __bionic_format_dlerror(const char* msg, const char* detail) { 56 char* buffer = __get_thread()->dlerror_buffer; 57 strlcpy(buffer, msg, __BIONIC_DLERROR_BUFFER_SIZE); 58 if (detail != nullptr) { 59 strlcat(buffer, ": ", __BIONIC_DLERROR_BUFFER_SIZE); 60 strlcat(buffer, detail, __BIONIC_DLERROR_BUFFER_SIZE); 61 } 62 63 __bionic_set_dlerror(buffer); 64 } 65 66 char* __dlerror() { 67 char* old_value = __bionic_set_dlerror(nullptr); 68 return old_value; 69 } 70 71 void __android_get_LD_LIBRARY_PATH(char* buffer, size_t buffer_size) { 72 ScopedPthreadMutexLocker locker(&g_dl_mutex); 73 do_android_get_LD_LIBRARY_PATH(buffer, buffer_size); 74 } 75 76 void __android_update_LD_LIBRARY_PATH(const char* ld_library_path) { 77 ScopedPthreadMutexLocker locker(&g_dl_mutex); 78 do_android_update_LD_LIBRARY_PATH(ld_library_path); 79 } 80 81 static void* dlopen_ext(const char* filename, 82 int flags, 83 const android_dlextinfo* extinfo, 84 const void* caller_addr) { 85 ScopedPthreadMutexLocker locker(&g_dl_mutex); 86 g_linker_logger.ResetState(); 87 void* result = do_dlopen(filename, flags, extinfo, caller_addr); 88 if (result == nullptr) { 89 __bionic_format_dlerror("dlopen failed", linker_get_error_buffer()); 90 return nullptr; 91 } 92 return result; 93 } 94 95 void* __android_dlopen_ext(const char* filename, 96 int flags, 97 const android_dlextinfo* extinfo, 98 const void* caller_addr) { 99 return dlopen_ext(filename, flags, extinfo, caller_addr); 100 } 101 102 void* __dlopen(const char* filename, int flags, const void* caller_addr) { 103 return dlopen_ext(filename, flags, nullptr, caller_addr); 104 } 105 106 void* dlsym_impl(void* handle, const char* symbol, const char* version, const void* caller_addr) { 107 ScopedPthreadMutexLocker locker(&g_dl_mutex); 108 g_linker_logger.ResetState(); 109 void* result; 110 if (!do_dlsym(handle, symbol, version, caller_addr, &result)) { 111 __bionic_format_dlerror(linker_get_error_buffer(), nullptr); 112 return nullptr; 113 } 114 115 return result; 116 } 117 118 void* __dlsym(void* handle, const char* symbol, const void* caller_addr) { 119 return dlsym_impl(handle, symbol, nullptr, caller_addr); 120 } 121 122 void* __dlvsym(void* handle, const char* symbol, const char* version, const void* caller_addr) { 123 return dlsym_impl(handle, symbol, version, caller_addr); 124 } 125 126 int __dladdr(const void* addr, Dl_info* info) { 127 ScopedPthreadMutexLocker locker(&g_dl_mutex); 128 return do_dladdr(addr, info); 129 } 130 131 int __dlclose(void* handle) { 132 ScopedPthreadMutexLocker locker(&g_dl_mutex); 133 int result = do_dlclose(handle); 134 if (result != 0) { 135 __bionic_format_dlerror("dlclose failed", linker_get_error_buffer()); 136 } 137 return result; 138 } 139 140 // This function is needed by libgcc.a (this is why there is no prefix for this one) 141 int dl_iterate_phdr(int (*cb)(dl_phdr_info* info, size_t size, void* data), void* data) { 142 ScopedPthreadMutexLocker locker(&g_dl_mutex); 143 return do_dl_iterate_phdr(cb, data); 144 } 145 146 #if defined(__arm__) 147 _Unwind_Ptr __dl_unwind_find_exidx(_Unwind_Ptr pc, int* pcount) { 148 ScopedPthreadMutexLocker locker(&g_dl_mutex); 149 return do_dl_unwind_find_exidx(pc, pcount); 150 } 151 #endif 152 153 void __android_set_application_target_sdk_version(uint32_t target) { 154 // lock to avoid modification in the middle of dlopen. 155 ScopedPthreadMutexLocker locker(&g_dl_mutex); 156 set_application_target_sdk_version(target); 157 } 158 159 uint32_t __android_get_application_target_sdk_version() { 160 return get_application_target_sdk_version(); 161 } 162 163 void __android_dlwarning(void* obj, void (*f)(void*, const char*)) { 164 ScopedPthreadMutexLocker locker(&g_dl_mutex); 165 get_dlwarning(obj, f); 166 } 167 168 bool __android_init_anonymous_namespace(const char* shared_libs_sonames, 169 const char* library_search_path) { 170 ScopedPthreadMutexLocker locker(&g_dl_mutex); 171 bool success = init_anonymous_namespace(shared_libs_sonames, library_search_path); 172 if (!success) { 173 __bionic_format_dlerror("android_init_anonymous_namespace failed", linker_get_error_buffer()); 174 } 175 176 return success; 177 } 178 179 android_namespace_t* __android_create_namespace(const char* name, 180 const char* ld_library_path, 181 const char* default_library_path, 182 uint64_t type, 183 const char* permitted_when_isolated_path, 184 android_namespace_t* parent_namespace, 185 const void* caller_addr) { 186 ScopedPthreadMutexLocker locker(&g_dl_mutex); 187 188 android_namespace_t* result = create_namespace(caller_addr, 189 name, 190 ld_library_path, 191 default_library_path, 192 type, 193 permitted_when_isolated_path, 194 parent_namespace); 195 196 if (result == nullptr) { 197 __bionic_format_dlerror("android_create_namespace failed", linker_get_error_buffer()); 198 } 199 200 return result; 201 } 202 203 bool __android_link_namespaces(android_namespace_t* namespace_from, 204 android_namespace_t* namespace_to, 205 const char* shared_libs_sonames) { 206 ScopedPthreadMutexLocker locker(&g_dl_mutex); 207 208 bool success = link_namespaces(namespace_from, namespace_to, shared_libs_sonames); 209 210 if (!success) { 211 __bionic_format_dlerror("android_link_namespaces failed", linker_get_error_buffer()); 212 } 213 214 return success; 215 } 216 217 android_namespace_t* __android_get_exported_namespace(const char* name) { 218 return get_exported_namespace(name); 219 } 220 221 void __cfi_fail(uint64_t CallSiteTypeId, void* Ptr, void *DiagData, void *CallerPc) { 222 CFIShadowWriter::CfiFail(CallSiteTypeId, Ptr, DiagData, CallerPc); 223 } 224 225 // name_offset: starting index of the name in libdl_info.strtab 226 #define ELF32_SYM_INITIALIZER(name_offset, value, shndx) \ 227 { name_offset, \ 228 reinterpret_cast<Elf32_Addr>(value), \ 229 /* st_size */ 0, \ 230 ((shndx) == 0) ? 0 : (STB_GLOBAL << 4), \ 231 /* st_other */ 0, \ 232 shndx, \ 233 } 234 235 #define ELF64_SYM_INITIALIZER(name_offset, value, shndx) \ 236 { name_offset, \ 237 ((shndx) == 0) ? 0 : (STB_GLOBAL << 4), \ 238 /* st_other */ 0, \ 239 shndx, \ 240 reinterpret_cast<Elf64_Addr>(value), \ 241 /* st_size */ 0, \ 242 } 243 244 static const char ANDROID_LIBDL_STRTAB[] = 245 // 0000000000111111 11112222222222333 333333344444444 44555555555566666 6666677777777778 8888888889999999999 246 // 0123456789012345 67890123456789012 345678901234567 89012345678901234 5678901234567890 1234567890123456789 247 "__loader_dlopen\0__loader_dlclose\0__loader_dlsym\0__loader_dlerror\0__loader_dladdr\0__loader_android_up" 248 // 1* 249 // 000000000011111111112 2222222223333333333444444444455555555 5566666666667777777777888 88888889999999999 250 // 012345678901234567890 1234567890123456789012345678901234567 8901234567890123456789012 34567890123456789 251 "date_LD_LIBRARY_PATH\0__loader_android_get_LD_LIBRARY_PATH\0__loader_dl_iterate_phdr\0__loader_android_" 252 // 2* 253 // 00000000001 1111111112222222222333333333344444444445555555555666 6666666777777777788888888889999999999 254 // 01234567890 1234567890123456789012345678901234567890123456789012 3456789012345678901234567890123456789 255 "dlopen_ext\0__loader_android_set_application_target_sdk_version\0__loader_android_get_application_targ" 256 // 3* 257 // 000000000011111 111112222222222333333333344444444445555555 5556666666666777777777788888888889 999999999 258 // 012345678901234 567890123456789012345678901234567890123456 7890123456789012345678901234567890 123456789 259 "et_sdk_version\0__loader_android_init_anonymous_namespace\0__loader_android_create_namespace\0__loader_" 260 // 4* 261 // 0000000 000111111111122222222223333 333333444444444455 555555556666666666777777777788888 888889999999999 262 // 0123456 789012345678901234567890123 456789012345678901 234567890123456789012345678901234 567890123456789 263 "dlvsym\0__loader_android_dlwarning\0__loader_cfi_fail\0__loader_android_link_namespaces\0__loader_androi" 264 // 5* 265 // 0000000000111111111122222 22222 266 // 0123456789012345678901234 56789 267 "d_get_exported_namespace\0" 268 #if defined(__arm__) 269 // 525 270 "__loader_dl_unwind_find_exidx\0" 271 #endif 272 ; 273 274 static ElfW(Sym) g_libdl_symtab[] = { 275 // Total length of libdl_info.strtab, including trailing 0. 276 // This is actually the STH_UNDEF entry. Technically, it's 277 // supposed to have st_name == 0, but instead, it points to an index 278 // in the strtab with a \0 to make iterating through the symtab easier. 279 ELFW(SYM_INITIALIZER)(sizeof(ANDROID_LIBDL_STRTAB) - 1, nullptr, 0), 280 ELFW(SYM_INITIALIZER)( 0, &__dlopen, 1), 281 ELFW(SYM_INITIALIZER)( 16, &__dlclose, 1), 282 ELFW(SYM_INITIALIZER)( 33, &__dlsym, 1), 283 ELFW(SYM_INITIALIZER)( 48, &__dlerror, 1), 284 ELFW(SYM_INITIALIZER)( 65, &__dladdr, 1), 285 ELFW(SYM_INITIALIZER)( 81, &__android_update_LD_LIBRARY_PATH, 1), 286 ELFW(SYM_INITIALIZER)(121, &__android_get_LD_LIBRARY_PATH, 1), 287 ELFW(SYM_INITIALIZER)(158, &dl_iterate_phdr, 1), 288 ELFW(SYM_INITIALIZER)(183, &__android_dlopen_ext, 1), 289 ELFW(SYM_INITIALIZER)(211, &__android_set_application_target_sdk_version, 1), 290 ELFW(SYM_INITIALIZER)(263, &__android_get_application_target_sdk_version, 1), 291 ELFW(SYM_INITIALIZER)(315, &__android_init_anonymous_namespace, 1), 292 ELFW(SYM_INITIALIZER)(357, &__android_create_namespace, 1), 293 ELFW(SYM_INITIALIZER)(391, &__dlvsym, 1), 294 ELFW(SYM_INITIALIZER)(407, &__android_dlwarning, 1), 295 ELFW(SYM_INITIALIZER)(434, &__cfi_fail, 1), 296 ELFW(SYM_INITIALIZER)(452, &__android_link_namespaces, 1), 297 ELFW(SYM_INITIALIZER)(485, &__android_get_exported_namespace, 1), 298 #if defined(__arm__) 299 ELFW(SYM_INITIALIZER)(525, &__dl_unwind_find_exidx, 1), 300 #endif 301 }; 302 303 // Fake out a hash table with a single bucket. 304 // 305 // A search of the hash table will look through g_libdl_symtab starting with index 1, then 306 // use g_libdl_chains to find the next index to look at. g_libdl_chains should be set up to 307 // walk through every element in g_libdl_symtab, and then end with 0 (sentinel value). 308 // 309 // That is, g_libdl_chains should look like { 0, 2, 3, ... N, 0 } where N is the number 310 // of actual symbols, or nelems(g_libdl_symtab)-1 (since the first element of g_libdl_symtab is not 311 // a real symbol). (See soinfo_elf_lookup().) 312 // 313 // Note that adding any new symbols here requires stubbing them out in libdl. 314 static unsigned g_libdl_buckets[1] = { 1 }; 315 #if defined(__arm__) 316 static unsigned g_libdl_chains[] = { 0, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 0 }; 317 #else 318 static unsigned g_libdl_chains[] = { 0, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 0 }; 319 #endif 320 321 static uint8_t __libdl_info_buf[sizeof(soinfo)] __attribute__((aligned(8))); 322 static soinfo* __libdl_info = nullptr; 323 324 // This is used by the dynamic linker. Every process gets these symbols for free. 325 soinfo* get_libdl_info(const char* linker_path) { 326 if (__libdl_info == nullptr) { 327 __libdl_info = new (__libdl_info_buf) soinfo(&g_default_namespace, linker_path, nullptr, 0, 0); 328 __libdl_info->flags_ |= FLAG_LINKED; 329 __libdl_info->strtab_ = ANDROID_LIBDL_STRTAB; 330 __libdl_info->symtab_ = g_libdl_symtab; 331 __libdl_info->nbucket_ = sizeof(g_libdl_buckets)/sizeof(unsigned); 332 __libdl_info->nchain_ = sizeof(g_libdl_chains)/sizeof(unsigned); 333 __libdl_info->bucket_ = g_libdl_buckets; 334 __libdl_info->chain_ = g_libdl_chains; 335 __libdl_info->ref_count_ = 1; 336 __libdl_info->strtab_size_ = sizeof(ANDROID_LIBDL_STRTAB); 337 __libdl_info->local_group_root_ = __libdl_info; 338 __libdl_info->soname_ = "ld-android.so"; 339 __libdl_info->target_sdk_version_ = __ANDROID_API__; 340 __libdl_info->generate_handle(); 341 #if defined(__work_around_b_24465209__) 342 strlcpy(__libdl_info->old_name_, __libdl_info->soname_, sizeof(__libdl_info->old_name_)); 343 #endif 344 } 345 346 return __libdl_info; 347 } 348
