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 #pragma once 18 19 #include <sys/types.h> 20 21 #include <optional> 22 #include <string> 23 #include <vector> 24 25 #include <libsnapshot/snapshot.h> 26 27 #include "block_dev_initializer.h" 28 29 namespace android { 30 namespace init { 31 32 // Fork and exec a new copy of snapuserd. 33 void LaunchFirstStageSnapuserd(); 34 35 class SnapuserdSelinuxHelper final { 36 using SnapshotManager = android::snapshot::SnapshotManager; 37 38 public: 39 SnapuserdSelinuxHelper(std::unique_ptr<SnapshotManager>&& sm, pid_t old_pid); 40 41 void StartTransition(); 42 void FinishTransition(); 43 44 // Return a helper for facilitating the selinux transition of snapuserd. 45 // If snapuserd is not in use, null is returned. StartTransition() should 46 // be called after reading policy. FinishTransition() should be called 47 // after loading policy. In between, no reads of /system or other dynamic 48 // partitions are possible. 49 static std::unique_ptr<SnapuserdSelinuxHelper> CreateIfNeeded(); 50 51 private: 52 void RelaunchFirstStageSnapuserd(); 53 void ExecSnapuserd(); 54 55 std::unique_ptr<SnapshotManager> sm_; 56 BlockDevInitializer block_dev_init_; 57 pid_t old_pid_; 58 std::vector<std::string> argv_; 59 }; 60 61 // Remove /dev/socket/snapuserd. This ensures that (1) the existing snapuserd 62 // will receive no new requests, and (2) the next copy we transition to can 63 // own the socket. 64 void CleanupSnapuserdSocket(); 65 66 // Kill an instance of snapuserd given a pid. 67 void KillFirstStageSnapuserd(pid_t pid); 68 69 // Save an open fd to /system/bin (in the ramdisk) into an environment. This is 70 // used to later execveat() snapuserd. 71 void SaveRamdiskPathToSnapuserd(); 72 73 // Returns true if first-stage snapuserd is running. 74 bool IsFirstStageSnapuserdRunning(); 75 76 // Return the pid of the first-stage instances of snapuserd, if it was started. 77 std::optional<pid_t> GetSnapuserdFirstStagePid(); 78 79 // Save an open fd to /system/bin (in the ramdisk) into an environment. This is 80 // used to later execveat() snapuserd. 81 void SaveRamdiskPathToSnapuserd(); 82 83 // Returns true if first-stage snapuserd is running. 84 bool IsFirstStageSnapuserdRunning(); 85 86 } // namespace init 87 } // namespace android 88