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 <string>
21 
22 #include <android-base/unique_fd.h>
23 
24 namespace android {
25 namespace snapshot {
26 
27 static constexpr uint32_t PACKET_SIZE = 512;
28 
29 static constexpr char kSnapuserdSocket[] = "snapuserd";
30 static constexpr char kSnapuserdSocketProxy[] = "snapuserd_proxy";
31 static constexpr char kDaemonAliveIndicator[] = "daemon-alive-indicator";
32 
33 // Ensure that the second-stage daemon for snapuserd is running.
34 bool EnsureSnapuserdStarted();
35 
36 class SnapuserdClient {
37   private:
38     android::base::unique_fd sockfd_;
39 
40     bool Sendmsg(const std::string& msg);
41     std::string Receivemsg();
42 
43     bool ValidateConnection();
44     std::string GetDaemonAliveIndicatorPath();
45 
46     void WaitForServiceToTerminate(std::chrono::milliseconds timeout_ms);
47 
48   public:
49     explicit SnapuserdClient(android::base::unique_fd&& sockfd);
SnapuserdClient()50     SnapuserdClient(){};
51 
52     // Attempt to connect to snapsuerd, wait for the daemon to start if
53     // connection failed.
54     static std::unique_ptr<SnapuserdClient> Connect(const std::string& socket_name,
55                                                     std::chrono::milliseconds timeout_ms);
56     // Attempt to connect to snapsuerd, but does not wait for the daemon to
57     // start.
58     static std::unique_ptr<SnapuserdClient> TryConnect(const std::string& socket_name,
59                                                        std::chrono::milliseconds timeout_ms);
60     bool StopSnapuserd();
61 
62     // Initializing a snapuserd handler is a three-step process:
63     //
64     //  1. Client invokes InitDmUserCow. This creates the snapuserd handler and validates the
65     //     COW. The number of sectors required for the dm-user target is returned.
66     //  2. Client creates the device-mapper device with the dm-user target.
67     //  3. Client calls AttachControlDevice.
68     //
69     // The misc_name must be the "misc_name" given to dm-user in step 2.
70     //
71     uint64_t InitDmUserCow(const std::string& misc_name, const std::string& cow_device,
72                            const std::string& backing_device,
73                            const std::string& base_path_merge = "");
74     bool AttachDmUser(const std::string& misc_name);
75 
76     // Wait for snapuserd to disassociate with a dm-user control device. This
77     // must ONLY be called if the control device has already been deleted.
78     bool WaitForDeviceDelete(const std::string& control_device);
79 
80     // Detach snapuserd. This shuts down the listener socket, and will cause
81     // snapuserd to gracefully exit once all handler threads have terminated.
82     // This should only be used on first-stage instances of snapuserd.
83     bool DetachSnapuserd();
84 
85     // Returns true if the snapuserd instance supports bridging a socket to second-stage init.
86     bool SupportsSecondStageSocketHandoff();
87 
88     // Returns true if the merge is started(or resumed from crash).
89     bool InitiateMerge(const std::string& misc_name);
90 
91     // Returns Merge completion percentage
92     double GetMergePercent();
93 
94     // Return the status of the snapshot
95     std::string QuerySnapshotStatus(const std::string& misc_name);
96 
97     // Check the update verification status - invoked by update_verifier during
98     // boot
99     bool QueryUpdateVerification();
100 
101     // Check if Snapuser daemon is ready post selinux transition after OTA boot
102     // This is invoked only by init as there is no sockets setup yet during
103     // selinux transition
104     bool IsTransitionedDaemonReady();
105 
106     // Remove the daemon-alive-indicator path post snapshot merge
107     bool RemoveTransitionedDaemonIndicator();
108 
109     // Notify init that snapuserd daemon is ready post selinux transition
110     void NotifyTransitionDaemonIsReady();
111 };
112 
113 }  // namespace snapshot
114 }  // namespace android
115