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Elliott Hughes3b297c42012-10-11 16:08:51 -07001/*
2 * Copyright (C) 2007 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
Elliott Hughes5419b942012-10-16 15:54:46 -070017#include "linker.h"
18
Elliott Hughes3b297c42012-10-11 16:08:51 -070019#include <pthread.h>
20#include <stdio.h>
Elliott Hughes5419b942012-10-16 15:54:46 -070021#include <stdlib.h>
Elliott Hughes05fc1d72015-01-28 18:02:33 -080022#include <string.h>
Dmitriy Ivanov19133522015-06-02 17:36:54 -070023#include <android/api-level.h>
Elliott Hughes3b297c42012-10-11 16:08:51 -070024
Elliott Hughes5419b942012-10-16 15:54:46 -070025#include <bionic/pthread_internal.h>
Elliott Hugheseb847bc2013-10-09 15:50:50 -070026#include "private/bionic_tls.h"
27#include "private/ScopedPthreadMutexLocker.h"
28#include "private/ThreadLocalBuffer.h"
Elliott Hughes3b297c42012-10-11 16:08:51 -070029
30/* This file hijacks the symbols stubbed out in libdl.so. */
31
Elliott Hughes212e0e32014-12-01 16:43:51 -080032static pthread_mutex_t g_dl_mutex = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;
Elliott Hughes3b297c42012-10-11 16:08:51 -070033
Elliott Hughes5419b942012-10-16 15:54:46 -070034static const char* __bionic_set_dlerror(char* new_value) {
Elliott Hughes2a0b8732013-10-08 18:50:24 -070035 char** dlerror_slot = &reinterpret_cast<char**>(__get_tls())[TLS_SLOT_DLERROR];
Elliott Hughes5419b942012-10-16 15:54:46 -070036
37 const char* old_value = *dlerror_slot;
38 *dlerror_slot = new_value;
39 return old_value;
Elliott Hughes3b297c42012-10-11 16:08:51 -070040}
41
Elliott Hughes5419b942012-10-16 15:54:46 -070042static void __bionic_format_dlerror(const char* msg, const char* detail) {
43 char* buffer = __get_thread()->dlerror_buffer;
44 strlcpy(buffer, msg, __BIONIC_DLERROR_BUFFER_SIZE);
Dmitriy Ivanov851135b2014-08-29 12:02:36 -070045 if (detail != nullptr) {
Elliott Hughes5419b942012-10-16 15:54:46 -070046 strlcat(buffer, ": ", __BIONIC_DLERROR_BUFFER_SIZE);
47 strlcat(buffer, detail, __BIONIC_DLERROR_BUFFER_SIZE);
48 }
49
50 __bionic_set_dlerror(buffer);
51}
52
53const char* dlerror() {
Dmitriy Ivanov851135b2014-08-29 12:02:36 -070054 const char* old_value = __bionic_set_dlerror(nullptr);
Elliott Hughes5419b942012-10-16 15:54:46 -070055 return old_value;
56}
57
Elliott Hughesa4aafd12014-01-13 16:37:47 -080058void android_get_LD_LIBRARY_PATH(char* buffer, size_t buffer_size) {
Elliott Hughes1728b232014-05-14 10:02:03 -070059 ScopedPthreadMutexLocker locker(&g_dl_mutex);
Elliott Hughesa4aafd12014-01-13 16:37:47 -080060 do_android_get_LD_LIBRARY_PATH(buffer, buffer_size);
61}
62
Elliott Hughescade4c32012-12-20 14:42:14 -080063void android_update_LD_LIBRARY_PATH(const char* ld_library_path) {
Elliott Hughes1728b232014-05-14 10:02:03 -070064 ScopedPthreadMutexLocker locker(&g_dl_mutex);
Elliott Hughescade4c32012-12-20 14:42:14 -080065 do_android_update_LD_LIBRARY_PATH(ld_library_path);
66}
67
Evgenii Stepanov0cdef7e2015-07-06 17:56:31 -070068static void* dlopen_ext(const char* filename, int flags,
Dmitriy Ivanove5cfafe2015-07-17 10:36:10 -070069 const android_dlextinfo* extinfo, void* caller_addr) {
Elliott Hughes1728b232014-05-14 10:02:03 -070070 ScopedPthreadMutexLocker locker(&g_dl_mutex);
Dimitry Ivanovd88e1f32016-03-24 15:30:30 -070071 void* result = do_dlopen(filename, flags, extinfo, caller_addr);
Dmitriy Ivanov851135b2014-08-29 12:02:36 -070072 if (result == nullptr) {
Elliott Hughes650be4e2013-03-05 18:47:58 -080073 __bionic_format_dlerror("dlopen failed", linker_get_error_buffer());
Dmitriy Ivanov851135b2014-08-29 12:02:36 -070074 return nullptr;
Elliott Hughes3b297c42012-10-11 16:08:51 -070075 }
Elliott Hughes3b297c42012-10-11 16:08:51 -070076 return result;
77}
78
Dmitriy Ivanovb648a8a2014-05-19 15:06:58 -070079void* android_dlopen_ext(const char* filename, int flags, const android_dlextinfo* extinfo) {
Evgenii Stepanov0cdef7e2015-07-06 17:56:31 -070080 void* caller_addr = __builtin_return_address(0);
Dmitriy Ivanove5cfafe2015-07-17 10:36:10 -070081 return dlopen_ext(filename, flags, extinfo, caller_addr);
Dmitriy Ivanovb648a8a2014-05-19 15:06:58 -070082}
83
Torne (Richard Coles)012cb452014-02-06 14:34:21 +000084void* dlopen(const char* filename, int flags) {
Evgenii Stepanov0cdef7e2015-07-06 17:56:31 -070085 void* caller_addr = __builtin_return_address(0);
Dmitriy Ivanove5cfafe2015-07-17 10:36:10 -070086 return dlopen_ext(filename, flags, nullptr, caller_addr);
Torne (Richard Coles)012cb452014-02-06 14:34:21 +000087}
88
Dimitry Ivanov9cf99cb2015-12-11 14:22:24 -080089void* dlsym_impl(void* handle, const char* symbol, const char* version, void* caller_addr) {
Dimitry Ivanov4a2c5aa2015-12-10 16:08:14 -080090 ScopedPthreadMutexLocker locker(&g_dl_mutex);
91 void* result;
Dimitry Ivanov9cf99cb2015-12-11 14:22:24 -080092 if (!do_dlsym(handle, symbol, version, caller_addr, &result)) {
Dimitry Ivanov4a2c5aa2015-12-10 16:08:14 -080093 __bionic_format_dlerror(linker_get_error_buffer(), nullptr);
Dmitriy Ivanov851135b2014-08-29 12:02:36 -070094 return nullptr;
Elliott Hughes3b297c42012-10-11 16:08:51 -070095 }
Dimitry Ivanov4a2c5aa2015-12-10 16:08:14 -080096
97 return result;
Elliott Hughes3b297c42012-10-11 16:08:51 -070098}
99
Dimitry Ivanov9cf99cb2015-12-11 14:22:24 -0800100void* dlsym(void* handle, const char* symbol) {
101 void* caller_addr = __builtin_return_address(0);
102 return dlsym_impl(handle, symbol, nullptr, caller_addr);
103}
104
105void* dlvsym(void* handle, const char* symbol, const char* version) {
106 void* caller_addr = __builtin_return_address(0);
107 return dlsym_impl(handle, symbol, version, caller_addr);
108}
109
Elliott Hughes3b297c42012-10-11 16:08:51 -0700110int dladdr(const void* addr, Dl_info* info) {
Elliott Hughes1728b232014-05-14 10:02:03 -0700111 ScopedPthreadMutexLocker locker(&g_dl_mutex);
Dimitry Ivanov4a2c5aa2015-12-10 16:08:14 -0800112 return do_dladdr(addr, info);
Elliott Hughes3b297c42012-10-11 16:08:51 -0700113}
114
115int dlclose(void* handle) {
Elliott Hughes1728b232014-05-14 10:02:03 -0700116 ScopedPthreadMutexLocker locker(&g_dl_mutex);
Dimitry Ivanovd88e1f32016-03-24 15:30:30 -0700117 int result = do_dlclose(handle);
118 if (result != 0) {
119 __bionic_format_dlerror("dlclose failed", linker_get_error_buffer());
120 }
121 return result;
Elliott Hughes3b297c42012-10-11 16:08:51 -0700122}
123
Dmitriy Ivanov7271caf2015-06-29 14:48:25 -0700124int dl_iterate_phdr(int (*cb)(dl_phdr_info* info, size_t size, void* data), void* data) {
125 ScopedPthreadMutexLocker locker(&g_dl_mutex);
126 return do_dl_iterate_phdr(cb, data);
127}
128
Dmitriy Ivanov79fd6682015-05-21 17:43:49 -0700129void android_set_application_target_sdk_version(uint32_t target) {
Dmitriy Ivanovd974e882015-05-27 18:29:41 -0700130 // lock to avoid modification in the middle of dlopen.
131 ScopedPthreadMutexLocker locker(&g_dl_mutex);
Dmitriy Ivanov79fd6682015-05-21 17:43:49 -0700132 set_application_target_sdk_version(target);
133}
134
135uint32_t android_get_application_target_sdk_version() {
136 return get_application_target_sdk_version();
137}
138
Dmitriy Ivanov1ffec1c2015-11-23 11:26:35 -0800139bool android_init_namespaces(const char* public_ns_sonames,
140 const char* anon_ns_library_path) {
Dmitriy Ivanov42d5fcb2015-10-29 17:01:24 -0700141 ScopedPthreadMutexLocker locker(&g_dl_mutex);
Dmitriy Ivanov1ffec1c2015-11-23 11:26:35 -0800142 bool success = init_namespaces(public_ns_sonames, anon_ns_library_path);
Dmitriy Ivanov42d5fcb2015-10-29 17:01:24 -0700143 if (!success) {
Dmitriy Ivanov1ffec1c2015-11-23 11:26:35 -0800144 __bionic_format_dlerror("android_init_namespaces failed", linker_get_error_buffer());
Dmitriy Ivanov42d5fcb2015-10-29 17:01:24 -0700145 }
146
147 return success;
148}
149
Dimitry Ivanovfc2da532016-05-12 15:20:21 -0700150android_namespace_t* android_create_namespace(const char* name,
151 const char* ld_library_path,
152 const char* default_library_path,
153 uint64_t type,
154 const char* permitted_when_isolated_path,
155 android_namespace_t* parent_namespace) {
Dimitry Ivanov7331fe12015-12-14 14:11:17 -0800156 void* caller_addr = __builtin_return_address(0);
Dmitriy Ivanov42d5fcb2015-10-29 17:01:24 -0700157 ScopedPthreadMutexLocker locker(&g_dl_mutex);
158
Dimitry Ivanovfc2da532016-05-12 15:20:21 -0700159 android_namespace_t* result = create_namespace(caller_addr,
160 name,
161 ld_library_path,
162 default_library_path,
163 type,
164 permitted_when_isolated_path,
165 parent_namespace);
Dmitriy Ivanov42d5fcb2015-10-29 17:01:24 -0700166
167 if (result == nullptr) {
168 __bionic_format_dlerror("android_create_namespace failed", linker_get_error_buffer());
169 }
170
171 return result;
172}
173
Elliott Hughes3b297c42012-10-11 16:08:51 -0700174// name_offset: starting index of the name in libdl_info.strtab
175#define ELF32_SYM_INITIALIZER(name_offset, value, shndx) \
176 { name_offset, \
Dmitriy Ivanov851135b2014-08-29 12:02:36 -0700177 reinterpret_cast<Elf32_Addr>(value), \
Elliott Hughes3b297c42012-10-11 16:08:51 -0700178 /* st_size */ 0, \
179 (shndx == 0) ? 0 : (STB_GLOBAL << 4), \
180 /* st_other */ 0, \
Elliott Hughesc00f2cb2013-10-04 17:01:33 -0700181 shndx, \
182 }
Elliott Hughes3b297c42012-10-11 16:08:51 -0700183
Elliott Hughesc00f2cb2013-10-04 17:01:33 -0700184#define ELF64_SYM_INITIALIZER(name_offset, value, shndx) \
185 { name_offset, \
186 (shndx == 0) ? 0 : (STB_GLOBAL << 4), \
187 /* st_other */ 0, \
188 shndx, \
Dmitriy Ivanov851135b2014-08-29 12:02:36 -0700189 reinterpret_cast<Elf64_Addr>(value), \
Elliott Hughesc00f2cb2013-10-04 17:01:33 -0700190 /* st_size */ 0, \
191 }
192
Dmitriy Ivanov79fd6682015-05-21 17:43:49 -0700193static const char ANDROID_LIBDL_STRTAB[] =
194 // 0000000 00011111 111112 22222222 2333333 3333444444444455555555556666666 6667777777777888888888899999 99999
195 // 0123456 78901234 567890 12345678 9012345 6789012345678901234567890123456 7890123456789012345678901234 56789
196 "dlopen\0dlclose\0dlsym\0dlerror\0dladdr\0android_update_LD_LIBRARY_PATH\0android_get_LD_LIBRARY_PATH\0dl_it"
197 // 00000000001 1111111112222222222 3333333333444444444455555555556666666666777 777777788888888889999999999
198 // 01234567890 1234567890123456789 0123456789012345678901234567890123456789012 345678901234567890123456789
199 "erate_phdr\0android_dlopen_ext\0android_set_application_target_sdk_version\0android_get_application_tar"
Dimitry Ivanov9cf99cb2015-12-11 14:22:24 -0800200 // 0000000000111111 111122222222223333333333 4444444444555555555566666 6666677
201 // 0123456789012345 678901234567890123456789 0123456789012345678901234 5678901
202 "get_sdk_version\0android_init_namespaces\0android_create_namespace\0dlvsym\0"
Elliott Hughesa4aafd12014-01-13 16:37:47 -0800203#if defined(__arm__)
Dimitry Ivanov9cf99cb2015-12-11 14:22:24 -0800204 // 272
Dmitriy Ivanov79fd6682015-05-21 17:43:49 -0700205 "dl_unwind_find_exidx\0"
Elliott Hughesa4aafd12014-01-13 16:37:47 -0800206#endif
Dmitriy Ivanov79fd6682015-05-21 17:43:49 -0700207 ;
Elliott Hughesa4aafd12014-01-13 16:37:47 -0800208
Elliott Hughes1728b232014-05-14 10:02:03 -0700209static ElfW(Sym) g_libdl_symtab[] = {
Elliott Hughes3b297c42012-10-11 16:08:51 -0700210 // Total length of libdl_info.strtab, including trailing 0.
211 // This is actually the STH_UNDEF entry. Technically, it's
212 // supposed to have st_name == 0, but instead, it points to an index
213 // in the strtab with a \0 to make iterating through the symtab easier.
Dmitriy Ivanov851135b2014-08-29 12:02:36 -0700214 ELFW(SYM_INITIALIZER)(sizeof(ANDROID_LIBDL_STRTAB) - 1, nullptr, 0),
Elliott Hughes0266ae52014-02-10 17:46:57 -0800215 ELFW(SYM_INITIALIZER)( 0, &dlopen, 1),
216 ELFW(SYM_INITIALIZER)( 7, &dlclose, 1),
217 ELFW(SYM_INITIALIZER)( 15, &dlsym, 1),
218 ELFW(SYM_INITIALIZER)( 21, &dlerror, 1),
219 ELFW(SYM_INITIALIZER)( 29, &dladdr, 1),
220 ELFW(SYM_INITIALIZER)( 36, &android_update_LD_LIBRARY_PATH, 1),
221 ELFW(SYM_INITIALIZER)( 67, &android_get_LD_LIBRARY_PATH, 1),
222 ELFW(SYM_INITIALIZER)( 95, &dl_iterate_phdr, 1),
Torne (Richard Coles)012cb452014-02-06 14:34:21 +0000223 ELFW(SYM_INITIALIZER)(111, &android_dlopen_ext, 1),
Dmitriy Ivanov79fd6682015-05-21 17:43:49 -0700224 ELFW(SYM_INITIALIZER)(130, &android_set_application_target_sdk_version, 1),
225 ELFW(SYM_INITIALIZER)(173, &android_get_application_target_sdk_version, 1),
Dmitriy Ivanov1ffec1c2015-11-23 11:26:35 -0800226 ELFW(SYM_INITIALIZER)(216, &android_init_namespaces, 1),
227 ELFW(SYM_INITIALIZER)(240, &android_create_namespace, 1),
Dimitry Ivanov9cf99cb2015-12-11 14:22:24 -0800228 ELFW(SYM_INITIALIZER)(265, &dlvsym, 1),
Elliott Hughes4eeb1f12013-10-25 17:38:02 -0700229#if defined(__arm__)
Dimitry Ivanov9cf99cb2015-12-11 14:22:24 -0800230 ELFW(SYM_INITIALIZER)(272, &dl_unwind_find_exidx, 1),
Elliott Hughes3b297c42012-10-11 16:08:51 -0700231#endif
232};
233
Elliott Hughes22d62922012-10-12 10:50:21 -0700234// Fake out a hash table with a single bucket.
Elliott Hughes22d62922012-10-12 10:50:21 -0700235//
Elliott Hughes1728b232014-05-14 10:02:03 -0700236// A search of the hash table will look through g_libdl_symtab starting with index 1, then
237// use g_libdl_chains to find the next index to look at. g_libdl_chains should be set up to
238// walk through every element in g_libdl_symtab, and then end with 0 (sentinel value).
Elliott Hughes22d62922012-10-12 10:50:21 -0700239//
Elliott Hughes1728b232014-05-14 10:02:03 -0700240// That is, g_libdl_chains should look like { 0, 2, 3, ... N, 0 } where N is the number
241// of actual symbols, or nelems(g_libdl_symtab)-1 (since the first element of g_libdl_symtab is not
Elliott Hughesa4aafd12014-01-13 16:37:47 -0800242// a real symbol). (See soinfo_elf_lookup().)
Elliott Hughes22d62922012-10-12 10:50:21 -0700243//
Elliott Hughesa4aafd12014-01-13 16:37:47 -0800244// Note that adding any new symbols here requires stubbing them out in libdl.
Elliott Hughes1728b232014-05-14 10:02:03 -0700245static unsigned g_libdl_buckets[1] = { 1 };
Elliott Hughes4eeb1f12013-10-25 17:38:02 -0700246#if defined(__arm__)
Dimitry Ivanov9cf99cb2015-12-11 14:22:24 -0800247static unsigned g_libdl_chains[] = { 0, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 0 };
Christopher Ferris24053a42013-08-19 17:45:09 -0700248#else
Dimitry Ivanov9cf99cb2015-12-11 14:22:24 -0800249static unsigned g_libdl_chains[] = { 0, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 0 };
Christopher Ferris24053a42013-08-19 17:45:09 -0700250#endif
Elliott Hughes3b297c42012-10-11 16:08:51 -0700251
Dmitriy Ivanovaae859c2015-03-31 11:14:03 -0700252static uint8_t __libdl_info_buf[sizeof(soinfo)] __attribute__((aligned(8)));
253static soinfo* __libdl_info = nullptr;
Dmitriy Ivanovd59e5002014-05-09 09:10:14 -0700254
Dmitriy Ivanov42d5fcb2015-10-29 17:01:24 -0700255extern android_namespace_t g_default_namespace;
256
Elliott Hughes22d62922012-10-12 10:50:21 -0700257// This is used by the dynamic linker. Every process gets these symbols for free.
Dmitriy Ivanovd59e5002014-05-09 09:10:14 -0700258soinfo* get_libdl_info() {
Dmitriy Ivanovaae859c2015-03-31 11:14:03 -0700259 if (__libdl_info == nullptr) {
Dmitriy Ivanov42d5fcb2015-10-29 17:01:24 -0700260 __libdl_info = new (__libdl_info_buf) soinfo(&g_default_namespace, "libdl.so", nullptr, 0, RTLD_GLOBAL);
Dmitriy Ivanovaae859c2015-03-31 11:14:03 -0700261 __libdl_info->flags_ |= FLAG_LINKED;
262 __libdl_info->strtab_ = ANDROID_LIBDL_STRTAB;
263 __libdl_info->symtab_ = g_libdl_symtab;
264 __libdl_info->nbucket_ = sizeof(g_libdl_buckets)/sizeof(unsigned);
265 __libdl_info->nchain_ = sizeof(g_libdl_chains)/sizeof(unsigned);
266 __libdl_info->bucket_ = g_libdl_buckets;
267 __libdl_info->chain_ = g_libdl_chains;
268 __libdl_info->ref_count_ = 1;
269 __libdl_info->strtab_size_ = sizeof(ANDROID_LIBDL_STRTAB);
270 __libdl_info->local_group_root_ = __libdl_info;
271 __libdl_info->soname_ = "libdl.so";
Dmitriy Ivanov19133522015-06-02 17:36:54 -0700272 __libdl_info->target_sdk_version_ = __ANDROID_API__;
Dimitry Ivanovd88e1f32016-03-24 15:30:30 -0700273 __libdl_info->generate_handle();
Mike Frysinger747d30e2015-10-20 14:06:25 -0400274#if defined(__work_around_b_24465209__)
Dmitriy Ivanovaae859c2015-03-31 11:14:03 -0700275 strlcpy(__libdl_info->old_name_, __libdl_info->soname_, sizeof(__libdl_info->old_name_));
276#endif
Dmitriy Ivanovd59e5002014-05-09 09:10:14 -0700277 }
Elliott Hughes3b297c42012-10-11 16:08:51 -0700278
Dmitriy Ivanovaae859c2015-03-31 11:14:03 -0700279 return __libdl_info;
Dmitriy Ivanovd59e5002014-05-09 09:10:14 -0700280}