platform_system_core/init/snapuserd_transition.h

88 lines
2.7 KiB
C++

/*
* Copyright (C) 2020 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <sys/types.h>
#include <optional>
#include <string>
#include <vector>
#include <libsnapshot/snapshot.h>
#include "block_dev_initializer.h"
namespace android {
namespace init {
// Fork and exec a new copy of snapuserd.
void LaunchFirstStageSnapuserd();
class SnapuserdSelinuxHelper final {
using SnapshotManager = android::snapshot::SnapshotManager;
public:
SnapuserdSelinuxHelper(std::unique_ptr<SnapshotManager>&& sm, pid_t old_pid);
void StartTransition();
void FinishTransition();
// Return a helper for facilitating the selinux transition of snapuserd.
// If snapuserd is not in use, null is returned. StartTransition() should
// be called after reading policy. FinishTransition() should be called
// after loading policy. In between, no reads of /system or other dynamic
// partitions are possible.
static std::unique_ptr<SnapuserdSelinuxHelper> CreateIfNeeded();
private:
void RelaunchFirstStageSnapuserd();
void ExecSnapuserd();
std::unique_ptr<SnapshotManager> sm_;
BlockDevInitializer block_dev_init_;
pid_t old_pid_;
std::vector<std::string> argv_;
};
// Remove /dev/socket/snapuserd. This ensures that (1) the existing snapuserd
// will receive no new requests, and (2) the next copy we transition to can
// own the socket.
void CleanupSnapuserdSocket();
// Kill an instance of snapuserd given a pid.
void KillFirstStageSnapuserd(pid_t pid);
// Save an open fd to /system/bin (in the ramdisk) into an environment. This is
// used to later execveat() snapuserd.
void SaveRamdiskPathToSnapuserd();
// Returns true if first-stage snapuserd is running.
bool IsFirstStageSnapuserdRunning();
// Return the pid of the first-stage instances of snapuserd, if it was started.
std::optional<pid_t> GetSnapuserdFirstStagePid();
// Save an open fd to /system/bin (in the ramdisk) into an environment. This is
// used to later execveat() snapuserd.
void SaveRamdiskPathToSnapuserd();
// Returns true if first-stage snapuserd is running.
bool IsFirstStageSnapuserdRunning();
} // namespace init
} // namespace android