native_loader.cpp revision 617f495cf7a8e07b433058fb7f4c7611b584fda9
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#include "log/log.h" 25#endif 26 27#include <algorithm> 28#include <vector> 29#include <string> 30#include <mutex> 31 32#include "android-base/file.h" 33#include "android-base/macros.h" 34#include "android-base/strings.h" 35 36namespace android { 37 38#if defined(__ANDROID__) 39static constexpr const char* kPublicNativeLibrariesSystemConfig = "/system/etc/public.libraries.txt"; 40static constexpr const char* kPublicNativeLibrariesVendorConfig = "/vendor/etc/public.libraries.txt"; 41 42class LibraryNamespaces { 43 public: 44 LibraryNamespaces() : initialized_(false) { } 45 46 android_namespace_t* Create(JNIEnv* env, 47 jobject class_loader, 48 bool is_shared, 49 jstring java_library_path, 50 jstring java_permitted_path) { 51 ScopedUtfChars library_path(env, java_library_path); 52 53 std::string permitted_path; 54 if (java_permitted_path != nullptr) { 55 ScopedUtfChars path(env, java_permitted_path); 56 permitted_path = path.c_str(); 57 } 58 59 if (!initialized_ && !InitPublicNamespace(library_path.c_str())) { 60 return nullptr; 61 } 62 63 android_namespace_t* ns = FindNamespaceByClassLoader(env, class_loader); 64 65 LOG_ALWAYS_FATAL_IF(ns != nullptr, 66 "There is already a namespace associated with this classloader"); 67 68 uint64_t namespace_type = ANDROID_NAMESPACE_TYPE_ISOLATED; 69 if (is_shared) { 70 namespace_type |= ANDROID_NAMESPACE_TYPE_SHARED; 71 } 72 73 ns = android_create_namespace("classloader-namespace", 74 nullptr, 75 library_path.c_str(), 76 namespace_type, 77 java_permitted_path != nullptr ? 78 permitted_path.c_str() : 79 nullptr); 80 81 if (ns != nullptr) { 82 namespaces_.push_back(std::make_pair(env->NewWeakGlobalRef(class_loader), ns)); 83 } 84 85 return ns; 86 } 87 88 android_namespace_t* FindNamespaceByClassLoader(JNIEnv* env, jobject class_loader) { 89 auto it = std::find_if(namespaces_.begin(), namespaces_.end(), 90 [&](const std::pair<jweak, android_namespace_t*>& value) { 91 return env->IsSameObject(value.first, class_loader); 92 }); 93 return it != namespaces_.end() ? it->second : nullptr; 94 } 95 96 void Initialize() { 97 std::vector<std::string> sonames; 98 99 LOG_ALWAYS_FATAL_IF(!ReadConfig(kPublicNativeLibrariesSystemConfig, &sonames), 100 "Error reading public native library list from \"%s\": %s", 101 kPublicNativeLibrariesSystemConfig, strerror(errno)); 102 // This file is optional, quietly ignore if the file does not exist. 103 ReadConfig(kPublicNativeLibrariesVendorConfig, &sonames); 104 105 // android_init_namespaces() expects all the public libraries 106 // to be loaded so that they can be found by soname alone. 107 // 108 // TODO(dimitry): this is a bit misleading since we do not know 109 // if the vendor public library is going to be opened from /vendor/lib 110 // we might as well end up loading them from /system/lib 111 // For now we rely on CTS test to catch things like this but 112 // it should probably be addressed in the future. 113 for (const auto& soname : sonames) { 114 dlopen(soname.c_str(), RTLD_NOW | RTLD_NODELETE); 115 } 116 117 public_libraries_ = base::Join(sonames, ':'); 118 } 119 120 private: 121 bool ReadConfig(const std::string& configFile, std::vector<std::string>* sonames) { 122 // Read list of public native libraries from the config file. 123 std::string file_content; 124 if(!base::ReadFileToString(configFile, &file_content)) { 125 return false; 126 } 127 128 std::vector<std::string> lines = base::Split(file_content, "\n"); 129 130 for (const auto& line : lines) { 131 auto trimmed_line = base::Trim(line); 132 if (trimmed_line[0] == '#' || trimmed_line.empty()) { 133 continue; 134 } 135 136 sonames->push_back(trimmed_line); 137 } 138 139 return true; 140 } 141 142 bool InitPublicNamespace(const char* library_path) { 143 // (http://b/25844435) - Some apps call dlopen from generated code (mono jited 144 // code is one example) unknown to linker in which case linker uses anonymous 145 // namespace. The second argument specifies the search path for the anonymous 146 // namespace which is the library_path of the classloader. 147 initialized_ = android_init_namespaces(public_libraries_.c_str(), library_path); 148 149 return initialized_; 150 } 151 152 bool initialized_; 153 std::vector<std::pair<jweak, android_namespace_t*>> namespaces_; 154 std::string public_libraries_; 155 156 157 DISALLOW_COPY_AND_ASSIGN(LibraryNamespaces); 158}; 159 160static std::mutex g_namespaces_mutex; 161static LibraryNamespaces* g_namespaces = new LibraryNamespaces; 162 163static bool namespaces_enabled(uint32_t target_sdk_version) { 164 return target_sdk_version > 0; 165} 166#endif 167 168void InitializeNativeLoader() { 169#if defined(__ANDROID__) 170 std::lock_guard<std::mutex> guard(g_namespaces_mutex); 171 g_namespaces->Initialize(); 172#endif 173} 174 175 176jstring CreateClassLoaderNamespace(JNIEnv* env, 177 int32_t target_sdk_version, 178 jobject class_loader, 179 bool is_shared, 180 jstring library_path, 181 jstring permitted_path) { 182#if defined(__ANDROID__) 183 if (!namespaces_enabled(target_sdk_version)) { 184 return nullptr; 185 } 186 187 std::lock_guard<std::mutex> guard(g_namespaces_mutex); 188 android_namespace_t* ns = g_namespaces->Create(env, 189 class_loader, 190 is_shared, 191 library_path, 192 permitted_path); 193 if (ns == nullptr) { 194 return env->NewStringUTF(dlerror()); 195 } 196#else 197 UNUSED(env, target_sdk_version, class_loader, is_shared, 198 library_path, permitted_path); 199#endif 200 return nullptr; 201} 202 203void* OpenNativeLibrary(JNIEnv* env, 204 int32_t target_sdk_version, 205 const char* path, 206 jobject class_loader, 207 jstring library_path) { 208#if defined(__ANDROID__) 209 if (!namespaces_enabled(target_sdk_version) || class_loader == nullptr) { 210 return dlopen(path, RTLD_NOW); 211 } 212 213 std::lock_guard<std::mutex> guard(g_namespaces_mutex); 214 android_namespace_t* ns = g_namespaces->FindNamespaceByClassLoader(env, class_loader); 215 216 if (ns == nullptr) { 217 // This is the case where the classloader was not created by ApplicationLoaders 218 // In this case we create an isolated not-shared namespace for it. 219 ns = g_namespaces->Create(env, class_loader, false, library_path, nullptr); 220 if (ns == nullptr) { 221 return nullptr; 222 } 223 } 224 225 android_dlextinfo extinfo; 226 extinfo.flags = ANDROID_DLEXT_USE_NAMESPACE; 227 extinfo.library_namespace = ns; 228 229 return android_dlopen_ext(path, RTLD_NOW, &extinfo); 230#else 231 UNUSED(env, target_sdk_version, class_loader, library_path); 232 return dlopen(path, RTLD_NOW); 233#endif 234} 235 236#if defined(__ANDROID__) 237android_namespace_t* FindNamespaceByClassLoader(JNIEnv* env, jobject class_loader) { 238 std::lock_guard<std::mutex> guard(g_namespaces_mutex); 239 return g_namespaces->FindNamespaceByClassLoader(env, class_loader); 240} 241#endif 242 243}; // android namespace 244