1 //
2 // Copyright (C) 2012 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 #ifndef UPDATE_ENGINE_PAYLOAD_CONSUMER_FILESYSTEM_VERIFIER_ACTION_H_
18 #define UPDATE_ENGINE_PAYLOAD_CONSUMER_FILESYSTEM_VERIFIER_ACTION_H_
19 
20 #include <sys/stat.h>
21 #include <sys/types.h>
22 
23 #include <string>
24 #include <vector>
25 
26 #include <brillo/streams/stream.h>
27 
28 #include "update_engine/common/action.h"
29 #include "update_engine/common/hash_calculator.h"
30 #include "update_engine/payload_consumer/install_plan.h"
31 
32 // This action will hash all the partitions of the target slot involved in the
33 // update. The hashes are then verified against the ones in the InstallPlan.
34 // If the target hash does not match, the action will fail. In case of failure,
35 // the error code will depend on whether the source slot hashes are provided and
36 // match.
37 
38 namespace chromeos_update_engine {
39 
40 // The step FilesystemVerifier is on. On kVerifyTargetHash it computes the hash
41 // on the target partitions based on the already populated size and verifies it
42 // matches the one in the target_hash in the InstallPlan.
43 // If the hash matches, then we skip the kVerifySourceHash step, otherwise we
44 // need to check if the source is the root cause of the mismatch.
45 enum class VerifierStep {
46   kVerifyTargetHash,
47   kVerifySourceHash,
48 };
49 
50 class FilesystemVerifierAction : public InstallPlanAction {
51  public:
52   FilesystemVerifierAction() = default;
53 
54   void PerformAction() override;
55   void TerminateProcessing() override;
56 
57   // Used for testing. Return true if Cleanup() has not yet been called due
58   // to a callback upon the completion or cancellation of the verifier action.
59   // A test should wait until IsCleanupPending() returns false before
60   // terminating the main loop.
61   bool IsCleanupPending() const;
62 
63   // Debugging/logging
StaticType()64   static std::string StaticType() { return "FilesystemVerifierAction"; }
Type()65   std::string Type() const override { return StaticType(); }
66 
67  private:
68   // Starts the hashing of the current partition. If there aren't any partitions
69   // remaining to be hashed, it finishes the action.
70   void StartPartitionHashing();
71 
72   // Schedules the asynchronous read of the filesystem.
73   void ScheduleRead();
74 
75   // Called from the main loop when a single read from |src_stream_| succeeds or
76   // fails, calling OnReadDoneCallback() and OnReadErrorCallback() respectively.
77   void OnReadDoneCallback(size_t bytes_read);
78   void OnReadErrorCallback(const brillo::Error* error);
79 
80   // When the read is done, finalize the hash checking of the current partition
81   // and continue checking the next one.
82   void FinishPartitionHashing();
83 
84   // Cleans up all the variables we use for async operations and tells the
85   // ActionProcessor we're done w/ |code| as passed in. |cancelled_| should be
86   // true if TerminateProcessing() was called.
87   void Cleanup(ErrorCode code);
88 
89   // The type of the partition that we are verifying.
90   VerifierStep verifier_step_ = VerifierStep::kVerifyTargetHash;
91 
92   // The index in the install_plan_.partitions vector of the partition currently
93   // being hashed.
94   size_t partition_index_{0};
95 
96   // If not null, the FileStream used to read from the device.
97   brillo::StreamPtr src_stream_;
98 
99   // Buffer for storing data we read.
100   brillo::Blob buffer_;
101 
102   bool read_done_{false};  // true if reached EOF on the input stream.
103   bool cancelled_{false};  // true if the action has been cancelled.
104 
105   // The install plan we're passed in via the input pipe.
106   InstallPlan install_plan_;
107 
108   // Calculates the hash of the data.
109   std::unique_ptr<HashCalculator> hasher_;
110 
111   // Reads and hashes this many bytes from the head of the input stream. This
112   // field is initialized from the corresponding InstallPlan::Partition size,
113   // when the partition starts to be hashed.
114   int64_t remaining_size_{0};
115 
116   DISALLOW_COPY_AND_ASSIGN(FilesystemVerifierAction);
117 };
118 
119 }  // namespace chromeos_update_engine
120 
121 #endif  // UPDATE_ENGINE_PAYLOAD_CONSUMER_FILESYSTEM_VERIFIER_ACTION_H_
122