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 enum class SnapshotDriver { 33 DM_SNAPSHOT, 34 DM_USER, 35 }; 36 37 // Fork and exec a new copy of snapuserd. 38 void LaunchFirstStageSnapuserd(SnapshotDriver driver); 39 40 class SnapuserdSelinuxHelper final { 41 using SnapshotManager = android::snapshot::SnapshotManager; 42 43 public: 44 SnapuserdSelinuxHelper(std::unique_ptr<SnapshotManager>&& sm, pid_t old_pid); 45 46 void StartTransition(); 47 void FinishTransition(); 48 49 // Return a helper for facilitating the selinux transition of snapuserd. 50 // If snapuserd is not in use, null is returned. StartTransition() should 51 // be called after reading policy. FinishTransition() should be called 52 // after loading policy. In between, no reads of /system or other dynamic 53 // partitions are possible. 54 static std::unique_ptr<SnapuserdSelinuxHelper> CreateIfNeeded(); 55 56 private: 57 void RelaunchFirstStageSnapuserd(); 58 void ExecSnapuserd(); 59 bool TestSnapuserdIsReady(); 60 61 std::unique_ptr<SnapshotManager> sm_; 62 BlockDevInitializer block_dev_init_; 63 pid_t old_pid_; 64 std::vector<std::string> argv_; 65 }; 66 67 // Remove /dev/socket/snapuserd. This ensures that (1) the existing snapuserd 68 // will receive no new requests, and (2) the next copy we transition to can 69 // own the socket. 70 void CleanupSnapuserdSocket(); 71 72 // Kill an instance of snapuserd given a pid. 73 void KillFirstStageSnapuserd(pid_t pid); 74 75 // Save an open fd to /system/bin (in the ramdisk) into an environment. This is 76 // used to later execveat() snapuserd. 77 void SaveRamdiskPathToSnapuserd(); 78 79 // Returns true if first-stage snapuserd is running. 80 bool IsFirstStageSnapuserdRunning(); 81 82 // Return the pid of the first-stage instances of snapuserd, if it was started. 83 std::optional<pid_t> GetSnapuserdFirstStagePid(); 84 85 // Return snapuserd info strings that were set during first-stage init. 86 std::vector<std::string> GetSnapuserdFirstStageInfo(); 87 88 // Save an open fd to /system/bin (in the ramdisk) into an environment. This is 89 // used to later execveat() snapuserd. 90 void SaveRamdiskPathToSnapuserd(); 91 92 // Returns true if first-stage snapuserd is running. 93 bool IsFirstStageSnapuserdRunning(); 94 95 } // namespace init 96 } // namespace android 97