native_loader.cpp revision 09a516bf161c5cabdaa3a67df5aa7fbac667f5f9
1/* 2 * Copyright (C) 2015 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 "nativeloader/native_loader.h" 18#include "ScopedUtfChars.h" 19 20#include <dlfcn.h> 21#ifdef __ANDROID__ 22#include <android/dlext.h> 23#include "cutils/properties.h" 24#define LOG_TAG "libnativeloader" 25#include "log/log.h" 26#endif 27 28#include <algorithm> 29#include <vector> 30#include <string> 31#include <mutex> 32 33#include "android-base/file.h" 34#include "android-base/macros.h" 35#include "android-base/strings.h" 36 37namespace android { 38 39#if defined(__ANDROID__) 40static constexpr const char* kPublicNativeLibrariesSystemConfigPathFromRoot = "/etc/public.libraries.txt"; 41static constexpr const char* kPublicNativeLibrariesVendorConfig = "/vendor/etc/public.libraries.txt"; 42 43class LibraryNamespaces { 44 public: 45 LibraryNamespaces() : initialized_(false) { } 46 47 android_namespace_t* Create(JNIEnv* env, 48 jobject class_loader, 49 bool is_shared, 50 jstring java_library_path, 51 jstring java_permitted_path, 52 int32_t target_sdk_version) { 53 ScopedUtfChars library_path(env, java_library_path); 54 55 std::string permitted_path; 56 if (java_permitted_path != nullptr) { 57 ScopedUtfChars path(env, java_permitted_path); 58 permitted_path = path.c_str(); 59 } else { 60 // (http://b/27588281) This is a workaround for apps using custom 61 // classloaders and calling System.load() with an absolute path which 62 // is outside of the classloader library search path. 63 // 64 // This part effectively allows such a classloader to access anything 65 // under /data 66 permitted_path = "/data"; 67 } 68 69 if (!initialized_ && !InitPublicNamespace(library_path.c_str(), target_sdk_version)) { 70 return nullptr; 71 } 72 73 android_namespace_t* ns = FindNamespaceByClassLoader(env, class_loader); 74 75 LOG_ALWAYS_FATAL_IF(ns != nullptr, 76 "There is already a namespace associated with this classloader"); 77 78 uint64_t namespace_type = ANDROID_NAMESPACE_TYPE_ISOLATED; 79 if (is_shared) { 80 namespace_type |= ANDROID_NAMESPACE_TYPE_SHARED; 81 } 82 83 ns = android_create_namespace("classloader-namespace", 84 nullptr, 85 library_path.c_str(), 86 namespace_type, 87 !permitted_path.empty() ? 88 permitted_path.c_str() : 89 nullptr); 90 91 if (ns != nullptr) { 92 namespaces_.push_back(std::make_pair(env->NewWeakGlobalRef(class_loader), ns)); 93 } 94 95 return ns; 96 } 97 98 android_namespace_t* FindNamespaceByClassLoader(JNIEnv* env, jobject class_loader) { 99 auto it = std::find_if(namespaces_.begin(), namespaces_.end(), 100 [&](const std::pair<jweak, android_namespace_t*>& value) { 101 return env->IsSameObject(value.first, class_loader); 102 }); 103 return it != namespaces_.end() ? it->second : nullptr; 104 } 105 106 void Initialize() { 107 std::vector<std::string> sonames; 108 const char* android_root_env = getenv("ANDROID_ROOT"); 109 std::string root_dir = android_root_env != nullptr ? android_root_env : "/system"; 110 std::string public_native_libraries_system_config = 111 root_dir + kPublicNativeLibrariesSystemConfigPathFromRoot; 112 113 LOG_ALWAYS_FATAL_IF(!ReadConfig(public_native_libraries_system_config, &sonames), 114 "Error reading public native library list from \"%s\": %s", 115 public_native_libraries_system_config.c_str(), strerror(errno)); 116 // This file is optional, quietly ignore if the file does not exist. 117 ReadConfig(kPublicNativeLibrariesVendorConfig, &sonames); 118 119 // android_init_namespaces() expects all the public libraries 120 // to be loaded so that they can be found by soname alone. 121 // 122 // TODO(dimitry): this is a bit misleading since we do not know 123 // if the vendor public library is going to be opened from /vendor/lib 124 // we might as well end up loading them from /system/lib 125 // For now we rely on CTS test to catch things like this but 126 // it should probably be addressed in the future. 127 for (const auto& soname : sonames) { 128 dlopen(soname.c_str(), RTLD_NOW | RTLD_NODELETE); 129 } 130 131 public_libraries_ = base::Join(sonames, ':'); 132 } 133 134 void Reset() { 135 namespaces_.clear(); 136 } 137 138 private: 139 bool ReadConfig(const std::string& configFile, std::vector<std::string>* sonames) { 140 // Read list of public native libraries from the config file. 141 std::string file_content; 142 if(!base::ReadFileToString(configFile, &file_content)) { 143 return false; 144 } 145 146 std::vector<std::string> lines = base::Split(file_content, "\n"); 147 148 for (const auto& line : lines) { 149 auto trimmed_line = base::Trim(line); 150 if (trimmed_line[0] == '#' || trimmed_line.empty()) { 151 continue; 152 } 153 154 sonames->push_back(trimmed_line); 155 } 156 157 return true; 158 } 159 160 bool InitPublicNamespace(const char* library_path, int32_t target_sdk_version) { 161 std::string publicNativeLibraries = public_libraries_; 162 163 UNUSED(target_sdk_version); 164 // (http://b/25844435) - Some apps call dlopen from generated code (mono jited 165 // code is one example) unknown to linker in which case linker uses anonymous 166 // namespace. The second argument specifies the search path for the anonymous 167 // namespace which is the library_path of the classloader. 168 initialized_ = android_init_namespaces(publicNativeLibraries.c_str(), library_path); 169 170 return initialized_; 171 } 172 173 bool initialized_; 174 std::vector<std::pair<jweak, android_namespace_t*>> namespaces_; 175 std::string public_libraries_; 176 177 178 DISALLOW_COPY_AND_ASSIGN(LibraryNamespaces); 179}; 180 181static std::mutex g_namespaces_mutex; 182static LibraryNamespaces* g_namespaces = new LibraryNamespaces; 183#endif 184 185void InitializeNativeLoader() { 186#if defined(__ANDROID__) 187 std::lock_guard<std::mutex> guard(g_namespaces_mutex); 188 g_namespaces->Initialize(); 189#endif 190} 191 192void ResetNativeLoader() { 193#if defined(__ANDROID__) 194 std::lock_guard<std::mutex> guard(g_namespaces_mutex); 195 g_namespaces->Reset(); 196#endif 197} 198 199jstring CreateClassLoaderNamespace(JNIEnv* env, 200 int32_t target_sdk_version, 201 jobject class_loader, 202 bool is_shared, 203 jstring library_path, 204 jstring permitted_path) { 205#if defined(__ANDROID__) 206 UNUSED(target_sdk_version); 207 std::lock_guard<std::mutex> guard(g_namespaces_mutex); 208 android_namespace_t* ns = g_namespaces->Create(env, 209 class_loader, 210 is_shared, 211 library_path, 212 permitted_path, 213 target_sdk_version); 214 if (ns == nullptr) { 215 return env->NewStringUTF(dlerror()); 216 } 217#else 218 UNUSED(env, target_sdk_version, class_loader, is_shared, 219 library_path, permitted_path); 220#endif 221 return nullptr; 222} 223 224void* OpenNativeLibrary(JNIEnv* env, 225 int32_t target_sdk_version, 226 const char* path, 227 jobject class_loader, 228 jstring library_path) { 229#if defined(__ANDROID__) 230 UNUSED(target_sdk_version); 231 if (class_loader == nullptr) { 232 return dlopen(path, RTLD_NOW); 233 } 234 235 std::lock_guard<std::mutex> guard(g_namespaces_mutex); 236 android_namespace_t* ns = g_namespaces->FindNamespaceByClassLoader(env, class_loader); 237 238 if (ns == nullptr) { 239 // This is the case where the classloader was not created by ApplicationLoaders 240 // In this case we create an isolated not-shared namespace for it. 241 ns = g_namespaces->Create(env, class_loader, false, library_path, nullptr, target_sdk_version); 242 if (ns == nullptr) { 243 return nullptr; 244 } 245 } 246 247 android_dlextinfo extinfo; 248 extinfo.flags = ANDROID_DLEXT_USE_NAMESPACE; 249 extinfo.library_namespace = ns; 250 251 return android_dlopen_ext(path, RTLD_NOW, &extinfo); 252#else 253 UNUSED(env, target_sdk_version, class_loader, library_path); 254 return dlopen(path, RTLD_NOW); 255#endif 256} 257 258bool CloseNativeLibrary(void* handle) { 259 return dlclose(handle) == 0; 260} 261 262#if defined(__ANDROID__) 263android_namespace_t* FindNamespaceByClassLoader(JNIEnv* env, jobject class_loader) { 264 std::lock_guard<std::mutex> guard(g_namespaces_mutex); 265 return g_namespaces->FindNamespaceByClassLoader(env, class_loader); 266} 267#endif 268 269}; // android namespace 270