1 /* 2 * Copyright (C) 2020 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 #ifndef ANDROID_APEXD_APEXD_ROLLBACK_UTILS_H_ 18 #define ANDROID_APEXD_APEXD_ROLLBACK_UTILS_H_ 19 20 #include <filesystem> 21 #include <string> 22 23 #include <android-base/logging.h> 24 #include <android-base/macros.h> 25 #include <android-base/result.h> 26 #include <android-base/scopeguard.h> 27 #include <logwrap/logwrap.h> 28 29 namespace android { 30 namespace apex { 31 32 static constexpr const char* kCpPath = "/system/bin/cp"; 33 34 /** 35 * Copies everything including directories from the "from" path to the "to" 36 * path. Note that this will fail if run before APEXes are mounted, due to a 37 * dependency on runtime. 38 */ 39 inline int32_t CopyDirectoryRecursive(const char* from, const char* to) { 40 const char* const argv[] = { 41 kCpPath, 42 "-F", /* delete any existing destination file first 43 (--remove-destination) */ 44 "-p", /* preserve timestamps, ownership, and permissions */ 45 "-R", /* recurse into subdirectories (DEST must be a directory) */ 46 "-P", /* Do not follow symlinks [default] */ 47 "-d", /* don't dereference symlinks */ 48 from, 49 to}; 50 51 LOG(DEBUG) << "Copying " << from << " to " << to; 52 return logwrap_fork_execvp(arraysize(argv), argv, nullptr, false, LOG_ALOG, 53 false, nullptr); 54 } 55 56 /** 57 * Deletes any files at to_path, and then copies all files and directories 58 * from from_path into to_path. Note that this must be run after APEXes are 59 * mounted. 60 */ 61 inline android::base::Result<void> ReplaceFiles(const std::string& from_path, 62 const std::string& to_path) { 63 namespace fs = std::filesystem; 64 65 std::error_code error_code; 66 fs::remove_all(to_path, error_code); 67 if (error_code) { 68 return android::base::Error() << "Failed to delete existing files at " 69 << to_path << " : " << error_code.message(); 70 } 71 72 auto deleter = [&] { 73 std::error_code error_code; 74 fs::remove_all(to_path, error_code); 75 if (error_code) { 76 LOG(ERROR) << "Failed to clean up files at " << to_path << " : " 77 << error_code.message(); 78 } 79 }; 80 auto scope_guard = android::base::make_scope_guard(deleter); 81 82 int rc = CopyDirectoryRecursive(from_path.c_str(), to_path.c_str()); 83 if (rc != 0) { 84 return android::base::Error() << "Failed to copy from [" << from_path 85 << "] to [" << to_path << "]"; 86 } 87 scope_guard.Disable(); 88 return {}; 89 } 90 91 } // namespace apex 92 } // namespace android 93 94 #endif // ANDROID_APEXD_APEXD_ROLLBACK_UTILS_H_ 95