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
38namespace 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.
45enum class VerifierStep {
46  kVerifyTargetHash,
47  kVerifySourceHash,
48};
49
50class 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
64  static std::string StaticType() { return "FilesystemVerifierAction"; }
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