1 /*
2 * Copyright (C) 2018 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
17 #include "art_api/dex_file_support.h"
18
19 #include <dlfcn.h>
20 #include <inttypes.h>
21 #include <mutex>
22 #include <sys/stat.h>
23
24 #ifndef STATIC_LIB
25 // Not used in the static lib, so avoid a dependency on this header in
26 // libdexfile_support_static.
27 #include <log/log.h>
28 #endif
29
30 namespace art_api {
31 namespace dex {
32
33 #if defined(STATIC_LIB)
34 #define DEFINE_ADEX_FILE_SYMBOL(DLFUNC) decltype(DLFUNC)* g_##DLFUNC = DLFUNC;
35 #else
36 #define DEFINE_ADEX_FILE_SYMBOL(DLFUNC) decltype(DLFUNC)* g_##DLFUNC = nullptr;
37 #endif
FOR_EACH_ADEX_FILE_SYMBOL(DEFINE_ADEX_FILE_SYMBOL)38 FOR_EACH_ADEX_FILE_SYMBOL(DEFINE_ADEX_FILE_SYMBOL)
39 #undef DEFINE_ADEX_FILE_SYMBOL
40
41 bool TryLoadLibdexfile([[maybe_unused]] std::string* err_msg) {
42 #if defined(STATIC_LIB)
43 // Nothing to do here since all function pointers are initialised statically.
44 return true;
45 #elif defined(NO_DEXFILE_SUPPORT)
46 *err_msg = "Dex file support not available.";
47 return false;
48 #else
49 // Use a plain old mutex since we want to try again if loading fails (to set
50 // err_msg, if nothing else).
51 static std::mutex load_mutex;
52 static bool is_loaded = false;
53 std::lock_guard<std::mutex> lock(load_mutex);
54
55 if (!is_loaded) {
56 // Check which version is already loaded to avoid loading both debug and
57 // release builds. We might also be backtracing from separate process, in
58 // which case neither is loaded.
59 const char* so_name = "libdexfiled.so";
60 void* handle = dlopen(so_name, RTLD_NOLOAD | RTLD_NOW | RTLD_NODELETE);
61 if (handle == nullptr) {
62 so_name = "libdexfile.so";
63 handle = dlopen(so_name, RTLD_NOW | RTLD_GLOBAL | RTLD_NODELETE);
64 }
65 if (handle == nullptr) {
66 *err_msg = dlerror();
67 return false;
68 }
69
70 #define RESOLVE_ADEX_FILE_SYMBOL(DLFUNC) \
71 auto DLFUNC##_ptr = reinterpret_cast<decltype(DLFUNC)*>(dlsym(handle, #DLFUNC)); \
72 if (DLFUNC##_ptr == nullptr) { \
73 *err_msg = dlerror(); \
74 return false; \
75 }
76 FOR_EACH_ADEX_FILE_SYMBOL(RESOLVE_ADEX_FILE_SYMBOL)
77 #undef RESOLVE_ADEX_FILE_SYMBOL
78
79 #define SET_ADEX_FILE_SYMBOL(DLFUNC) g_##DLFUNC = DLFUNC##_ptr;
80 FOR_EACH_ADEX_FILE_SYMBOL(SET_ADEX_FILE_SYMBOL);
81 #undef SET_ADEX_FILE_SYMBOL
82
83 is_loaded = true;
84 }
85
86 return is_loaded;
87 #endif // !defined(NO_DEXFILE_SUPPORT) && !defined(STATIC_LIB)
88 }
89
LoadLibdexfile()90 void LoadLibdexfile() {
91 #ifndef STATIC_LIB
92 if (std::string err_msg; !TryLoadLibdexfile(&err_msg)) {
93 LOG_ALWAYS_FATAL("%s", err_msg.c_str());
94 }
95 #endif
96 }
97
98 } // namespace dex
99 } // namespace art_api
100