| /* |
| * Copyright (C) 2007 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "linker.h" |
| #include "linker_dlwarning.h" |
| |
| #include <pthread.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <android/api-level.h> |
| |
| #include <bionic/pthread_internal.h> |
| #include "private/bionic_tls.h" |
| #include "private/ScopedPthreadMutexLocker.h" |
| #include "private/ThreadLocalBuffer.h" |
| |
| /* This file hijacks the symbols stubbed out in libdl.so. */ |
| |
| static pthread_mutex_t g_dl_mutex = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP; |
| |
| static const char* __bionic_set_dlerror(char* new_value) { |
| char** dlerror_slot = &reinterpret_cast<char**>(__get_tls())[TLS_SLOT_DLERROR]; |
| |
| const char* old_value = *dlerror_slot; |
| *dlerror_slot = new_value; |
| return old_value; |
| } |
| |
| static void __bionic_format_dlerror(const char* msg, const char* detail) { |
| char* buffer = __get_thread()->dlerror_buffer; |
| strlcpy(buffer, msg, __BIONIC_DLERROR_BUFFER_SIZE); |
| if (detail != nullptr) { |
| strlcat(buffer, ": ", __BIONIC_DLERROR_BUFFER_SIZE); |
| strlcat(buffer, detail, __BIONIC_DLERROR_BUFFER_SIZE); |
| } |
| |
| __bionic_set_dlerror(buffer); |
| } |
| |
| const char* dlerror() { |
| const char* old_value = __bionic_set_dlerror(nullptr); |
| return old_value; |
| } |
| |
| void android_get_LD_LIBRARY_PATH(char* buffer, size_t buffer_size) { |
| ScopedPthreadMutexLocker locker(&g_dl_mutex); |
| do_android_get_LD_LIBRARY_PATH(buffer, buffer_size); |
| } |
| |
| void android_update_LD_LIBRARY_PATH(const char* ld_library_path) { |
| ScopedPthreadMutexLocker locker(&g_dl_mutex); |
| do_android_update_LD_LIBRARY_PATH(ld_library_path); |
| } |
| |
| static void* dlopen_ext(const char* filename, int flags, |
| const android_dlextinfo* extinfo, void* caller_addr) { |
| ScopedPthreadMutexLocker locker(&g_dl_mutex); |
| void* result = do_dlopen(filename, flags, extinfo, caller_addr); |
| if (result == nullptr) { |
| __bionic_format_dlerror("dlopen failed", linker_get_error_buffer()); |
| return nullptr; |
| } |
| return result; |
| } |
| |
| void* android_dlopen_ext(const char* filename, int flags, const android_dlextinfo* extinfo) { |
| void* caller_addr = __builtin_return_address(0); |
| return dlopen_ext(filename, flags, extinfo, caller_addr); |
| } |
| |
| void* dlopen(const char* filename, int flags) { |
| void* caller_addr = __builtin_return_address(0); |
| return dlopen_ext(filename, flags, nullptr, caller_addr); |
| } |
| |
| void* dlsym_impl(void* handle, const char* symbol, const char* version, void* caller_addr) { |
| ScopedPthreadMutexLocker locker(&g_dl_mutex); |
| void* result; |
| if (!do_dlsym(handle, symbol, version, caller_addr, &result)) { |
| __bionic_format_dlerror(linker_get_error_buffer(), nullptr); |
| return nullptr; |
| } |
| |
| return result; |
| } |
| |
| void* dlsym(void* handle, const char* symbol) { |
| void* caller_addr = __builtin_return_address(0); |
| return dlsym_impl(handle, symbol, nullptr, caller_addr); |
| } |
| |
| void* dlvsym(void* handle, const char* symbol, const char* version) { |
| void* caller_addr = __builtin_return_address(0); |
| return dlsym_impl(handle, symbol, version, caller_addr); |
| } |
| |
| int dladdr(const void* addr, Dl_info* info) { |
| ScopedPthreadMutexLocker locker(&g_dl_mutex); |
| return do_dladdr(addr, info); |
| } |
| |
| int dlclose(void* handle) { |
| ScopedPthreadMutexLocker locker(&g_dl_mutex); |
| int result = do_dlclose(handle); |
| if (result != 0) { |
| __bionic_format_dlerror("dlclose failed", linker_get_error_buffer()); |
| } |
| return result; |
| } |
| |
| int dl_iterate_phdr(int (*cb)(dl_phdr_info* info, size_t size, void* data), void* data) { |
| ScopedPthreadMutexLocker locker(&g_dl_mutex); |
| return do_dl_iterate_phdr(cb, data); |
| } |
| |
| void android_set_application_target_sdk_version(uint32_t target) { |
| // lock to avoid modification in the middle of dlopen. |
| ScopedPthreadMutexLocker locker(&g_dl_mutex); |
| set_application_target_sdk_version(target); |
| } |
| |
| uint32_t android_get_application_target_sdk_version() { |
| return get_application_target_sdk_version(); |
| } |
| |
| void android_dlwarning(void* obj, void (*f)(void*, const char*)) { |
| ScopedPthreadMutexLocker locker(&g_dl_mutex); |
| get_dlwarning(obj, f); |
| } |
| |
| bool android_init_namespaces(const char* public_ns_sonames, |
| const char* anon_ns_library_path) { |
| ScopedPthreadMutexLocker locker(&g_dl_mutex); |
| bool success = init_namespaces(public_ns_sonames, anon_ns_library_path); |
| if (!success) { |
| __bionic_format_dlerror("android_init_namespaces failed", linker_get_error_buffer()); |
| } |
| |
| return success; |
| } |
| |
| android_namespace_t* android_create_namespace(const char* name, |
| const char* ld_library_path, |
| const char* default_library_path, |
| uint64_t type, |
| const char* permitted_when_isolated_path, |
| android_namespace_t* parent_namespace) { |
| void* caller_addr = __builtin_return_address(0); |
| ScopedPthreadMutexLocker locker(&g_dl_mutex); |
| |
| android_namespace_t* result = create_namespace(caller_addr, |
| name, |
| ld_library_path, |
| default_library_path, |
| type, |
| permitted_when_isolated_path, |
| parent_namespace); |
| |
| if (result == nullptr) { |
| __bionic_format_dlerror("android_create_namespace failed", linker_get_error_buffer()); |
| } |
| |
| return result; |
| } |
| |
| // name_offset: starting index of the name in libdl_info.strtab |
| #define ELF32_SYM_INITIALIZER(name_offset, value, shndx) \ |
| { name_offset, \ |
| reinterpret_cast<Elf32_Addr>(value), \ |
| /* st_size */ 0, \ |
| (shndx == 0) ? 0 : (STB_GLOBAL << 4), \ |
| /* st_other */ 0, \ |
| shndx, \ |
| } |
| |
| #define ELF64_SYM_INITIALIZER(name_offset, value, shndx) \ |
| { name_offset, \ |
| (shndx == 0) ? 0 : (STB_GLOBAL << 4), \ |
| /* st_other */ 0, \ |
| shndx, \ |
| reinterpret_cast<Elf64_Addr>(value), \ |
| /* st_size */ 0, \ |
| } |
| |
| static const char ANDROID_LIBDL_STRTAB[] = |
| // 0000000 00011111 111112 22222222 2333333 3333444444444455555555556666666 6667777777777888888888899999 99999 |
| // 0123456 78901234 567890 12345678 9012345 6789012345678901234567890123456 7890123456789012345678901234 56789 |
| "dlopen\0dlclose\0dlsym\0dlerror\0dladdr\0android_update_LD_LIBRARY_PATH\0android_get_LD_LIBRARY_PATH\0dl_it" |
| // 00000000001 1111111112222222222 3333333333444444444455555555556666666666777 777777788888888889999999999 |
| // 01234567890 1234567890123456789 0123456789012345678901234567890123456789012 345678901234567890123456789 |
| "erate_phdr\0android_dlopen_ext\0android_set_application_target_sdk_version\0android_get_application_tar" |
| // 0000000000111111 111122222222223333333333 4444444444555555555566666 6666677 777777778888888888 |
| // 0123456789012345 678901234567890123456789 0123456789012345678901234 5678901 234567890123456789 |
| "get_sdk_version\0android_init_namespaces\0android_create_namespace\0dlvsym\0android_dlwarning\0" |
| #if defined(__arm__) |
| // 290 |
| "dl_unwind_find_exidx\0" |
| #endif |
| ; |
| |
| static ElfW(Sym) g_libdl_symtab[] = { |
| // Total length of libdl_info.strtab, including trailing 0. |
| // This is actually the STH_UNDEF entry. Technically, it's |
| // supposed to have st_name == 0, but instead, it points to an index |
| // in the strtab with a \0 to make iterating through the symtab easier. |
| ELFW(SYM_INITIALIZER)(sizeof(ANDROID_LIBDL_STRTAB) - 1, nullptr, 0), |
| ELFW(SYM_INITIALIZER)( 0, &dlopen, 1), |
| ELFW(SYM_INITIALIZER)( 7, &dlclose, 1), |
| ELFW(SYM_INITIALIZER)( 15, &dlsym, 1), |
| ELFW(SYM_INITIALIZER)( 21, &dlerror, 1), |
| ELFW(SYM_INITIALIZER)( 29, &dladdr, 1), |
| ELFW(SYM_INITIALIZER)( 36, &android_update_LD_LIBRARY_PATH, 1), |
| ELFW(SYM_INITIALIZER)( 67, &android_get_LD_LIBRARY_PATH, 1), |
| ELFW(SYM_INITIALIZER)( 95, &dl_iterate_phdr, 1), |
| ELFW(SYM_INITIALIZER)(111, &android_dlopen_ext, 1), |
| ELFW(SYM_INITIALIZER)(130, &android_set_application_target_sdk_version, 1), |
| ELFW(SYM_INITIALIZER)(173, &android_get_application_target_sdk_version, 1), |
| ELFW(SYM_INITIALIZER)(216, &android_init_namespaces, 1), |
| ELFW(SYM_INITIALIZER)(240, &android_create_namespace, 1), |
| ELFW(SYM_INITIALIZER)(265, &dlvsym, 1), |
| ELFW(SYM_INITIALIZER)(272, &android_dlwarning, 1), |
| #if defined(__arm__) |
| ELFW(SYM_INITIALIZER)(290, &dl_unwind_find_exidx, 1), |
| #endif |
| }; |
| |
| // Fake out a hash table with a single bucket. |
| // |
| // A search of the hash table will look through g_libdl_symtab starting with index 1, then |
| // use g_libdl_chains to find the next index to look at. g_libdl_chains should be set up to |
| // walk through every element in g_libdl_symtab, and then end with 0 (sentinel value). |
| // |
| // That is, g_libdl_chains should look like { 0, 2, 3, ... N, 0 } where N is the number |
| // of actual symbols, or nelems(g_libdl_symtab)-1 (since the first element of g_libdl_symtab is not |
| // a real symbol). (See soinfo_elf_lookup().) |
| // |
| // Note that adding any new symbols here requires stubbing them out in libdl. |
| static unsigned g_libdl_buckets[1] = { 1 }; |
| #if defined(__arm__) |
| static unsigned g_libdl_chains[] = { 0, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 0 }; |
| #else |
| static unsigned g_libdl_chains[] = { 0, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 0 }; |
| #endif |
| |
| static uint8_t __libdl_info_buf[sizeof(soinfo)] __attribute__((aligned(8))); |
| static soinfo* __libdl_info = nullptr; |
| |
| extern android_namespace_t g_default_namespace; |
| |
| // This is used by the dynamic linker. Every process gets these symbols for free. |
| soinfo* get_libdl_info() { |
| if (__libdl_info == nullptr) { |
| __libdl_info = new (__libdl_info_buf) soinfo(&g_default_namespace, "libdl.so", nullptr, 0, RTLD_GLOBAL); |
| __libdl_info->flags_ |= FLAG_LINKED; |
| __libdl_info->strtab_ = ANDROID_LIBDL_STRTAB; |
| __libdl_info->symtab_ = g_libdl_symtab; |
| __libdl_info->nbucket_ = sizeof(g_libdl_buckets)/sizeof(unsigned); |
| __libdl_info->nchain_ = sizeof(g_libdl_chains)/sizeof(unsigned); |
| __libdl_info->bucket_ = g_libdl_buckets; |
| __libdl_info->chain_ = g_libdl_chains; |
| __libdl_info->ref_count_ = 1; |
| __libdl_info->strtab_size_ = sizeof(ANDROID_LIBDL_STRTAB); |
| __libdl_info->local_group_root_ = __libdl_info; |
| __libdl_info->soname_ = "libdl.so"; |
| __libdl_info->target_sdk_version_ = __ANDROID_API__; |
| __libdl_info->generate_handle(); |
| #if defined(__work_around_b_24465209__) |
| strlcpy(__libdl_info->old_name_, __libdl_info->soname_, sizeof(__libdl_info->old_name_)); |
| #endif |
| } |
| |
| return __libdl_info; |
| } |