1 // Copyright (C) 2020 The Android Open Source Project
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 //      http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14 
15 #pragma once
16 
17 #include <unistd.h>
18 
19 #include <chrono>
20 #include <cstring>
21 #include <iostream>
22 #include <string>
23 #include <thread>
24 #include <vector>
25 
26 #include <android-base/unique_fd.h>
27 
28 namespace android {
29 namespace snapshot {
30 
31 static constexpr uint32_t PACKET_SIZE = 512;
32 
33 static constexpr char kSnapuserdSocket[] = "snapuserd";
34 static constexpr char kSnapuserdSocketProxy[] = "snapuserd_proxy";
35 static constexpr char kDaemonAliveIndicator[] = "daemon-alive-indicator";
36 
37 // Ensure that the second-stage daemon for snapuserd is running.
38 bool EnsureSnapuserdStarted();
39 
40 class SnapuserdClient {
41   private:
42     android::base::unique_fd sockfd_;
43 
44     bool Sendmsg(const std::string& msg);
45     std::string Receivemsg();
46 
47     bool ValidateConnection();
48     std::string GetDaemonAliveIndicatorPath();
49 
50     void WaitForServiceToTerminate(std::chrono::milliseconds timeout_ms);
51 
52   public:
53     explicit SnapuserdClient(android::base::unique_fd&& sockfd);
SnapuserdClient()54     SnapuserdClient(){};
55 
56     static std::unique_ptr<SnapuserdClient> Connect(const std::string& socket_name,
57                                                     std::chrono::milliseconds timeout_ms);
58 
59     bool StopSnapuserd();
60 
61     // Initializing a snapuserd handler is a three-step process:
62     //
63     //  1. Client invokes InitDmUserCow. This creates the snapuserd handler and validates the
64     //     COW. The number of sectors required for the dm-user target is returned.
65     //  2. Client creates the device-mapper device with the dm-user target.
66     //  3. Client calls AttachControlDevice.
67     //
68     // The misc_name must be the "misc_name" given to dm-user in step 2.
69     //
70     uint64_t InitDmUserCow(const std::string& misc_name, const std::string& cow_device,
71                            const std::string& backing_device,
72                            const std::string& base_path_merge = "");
73     bool AttachDmUser(const std::string& misc_name);
74 
75     // Wait for snapuserd to disassociate with a dm-user control device. This
76     // must ONLY be called if the control device has already been deleted.
77     bool WaitForDeviceDelete(const std::string& control_device);
78 
79     // Detach snapuserd. This shuts down the listener socket, and will cause
80     // snapuserd to gracefully exit once all handler threads have terminated.
81     // This should only be used on first-stage instances of snapuserd.
82     bool DetachSnapuserd();
83 
84     // Returns true if the snapuserd instance supports bridging a socket to second-stage init.
85     bool SupportsSecondStageSocketHandoff();
86 
87     // Returns true if the merge is started(or resumed from crash).
88     bool InitiateMerge(const std::string& misc_name);
89 
90     // Returns Merge completion percentage
91     double GetMergePercent();
92 
93     // Return the status of the snapshot
94     std::string QuerySnapshotStatus(const std::string& misc_name);
95 
96     // Check the update verification status - invoked by update_verifier during
97     // boot
98     bool QueryUpdateVerification();
99 
100     // Check if Snapuser daemon is ready post selinux transition after OTA boot
101     // This is invoked only by init as there is no sockets setup yet during
102     // selinux transition
103     bool IsTransitionedDaemonReady();
104 
105     // Remove the daemon-alive-indicator path post snapshot merge
106     bool RemoveTransitionedDaemonIndicator();
107 
108     // Notify init that snapuserd daemon is ready post selinux transition
109     void NotifyTransitionDaemonIsReady();
110 };
111 
112 }  // namespace snapshot
113 }  // namespace android
114