Split payload application code into a subdirectory.

This patch splits from the main libupdate_engine code the part that
is strictly used to download and apply a payload into a new static
library, moving the code to subdirectories. The new library is divided
in two subdirectories: common/ and payload_consumer/, and should not
depend on other update_engine files outside those two subdirectories.
The main difference between those two is that the common/ tools are more
generic and not tied to the payload consumer process, but otherwise they
are both compiled together.

There are still dependencies from the new libpayload_consumer library
into the main directory files and DBus generated files. Those will be
addressed in follow up CLs.

Bug: 25197634
Test: FEATURES=test emerge-link update_engine; `mm` on Brillo.

Change-Id: Id8d0204ea573627e6e26ca9ea17b9592ca95bc23
diff --git a/payload_consumer/delta_performer.h b/payload_consumer/delta_performer.h
new file mode 100644
index 0000000..db938c1
--- /dev/null
+++ b/payload_consumer/delta_performer.h
@@ -0,0 +1,396 @@
+//
+// Copyright (C) 2010 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.
+//
+
+#ifndef UPDATE_ENGINE_PAYLOAD_CONSUMER_DELTA_PERFORMER_H_
+#define UPDATE_ENGINE_PAYLOAD_CONSUMER_DELTA_PERFORMER_H_
+
+#include <inttypes.h>
+
+#include <string>
+#include <vector>
+
+#include <base/time/time.h>
+#include <brillo/secure_blob.h>
+#include <google/protobuf/repeated_field.h>
+#include <gtest/gtest_prod.h>  // for FRIEND_TEST
+
+#include "update_engine/common/hash_calculator.h"
+#include "update_engine/common/platform_constants.h"
+#include "update_engine/payload_consumer/file_descriptor.h"
+#include "update_engine/payload_consumer/file_writer.h"
+#include "update_engine/payload_consumer/install_plan.h"
+#include "update_engine/system_state.h"
+#include "update_engine/update_metadata.pb.h"
+
+namespace chromeos_update_engine {
+
+class PrefsInterface;
+
+// This class performs the actions in a delta update synchronously. The delta
+// update itself should be passed in in chunks as it is received.
+
+class DeltaPerformer : public FileWriter {
+ public:
+  enum MetadataParseResult {
+    kMetadataParseSuccess,
+    kMetadataParseError,
+    kMetadataParseInsufficientData,
+  };
+
+  static const uint64_t kDeltaVersionOffset;
+  static const uint64_t kDeltaVersionSize;
+  static const uint64_t kDeltaManifestSizeOffset;
+  static const uint64_t kDeltaManifestSizeSize;
+  static const uint64_t kDeltaMetadataSignatureSizeSize;
+  static const uint64_t kMaxPayloadHeaderSize;
+  static const uint64_t kSupportedMajorPayloadVersion;
+  static const uint32_t kSupportedMinorPayloadVersion;
+
+  // Defines the granularity of progress logging in terms of how many "completed
+  // chunks" we want to report at the most.
+  static const unsigned kProgressLogMaxChunks;
+  // Defines a timeout since the last progress was logged after which we want to
+  // force another log message (even if the current chunk was not completed).
+  static const unsigned kProgressLogTimeoutSeconds;
+  // These define the relative weights (0-100) we give to the different work
+  // components associated with an update when computing an overall progress.
+  // Currently they include the download progress and the number of completed
+  // operations. They must add up to one hundred (100).
+  static const unsigned kProgressDownloadWeight;
+  static const unsigned kProgressOperationsWeight;
+
+  DeltaPerformer(PrefsInterface* prefs,
+                 SystemState* system_state,
+                 InstallPlan* install_plan)
+      : prefs_(prefs),
+        system_state_(system_state),
+        install_plan_(install_plan) {}
+
+  // FileWriter's Write implementation where caller doesn't care about
+  // error codes.
+  bool Write(const void* bytes, size_t count) override {
+    ErrorCode error;
+    return Write(bytes, count, &error);
+  }
+
+  // FileWriter's Write implementation that returns a more specific |error| code
+  // in case of failures in Write operation.
+  bool Write(const void* bytes, size_t count, ErrorCode *error) override;
+
+  // Wrapper around close. Returns 0 on success or -errno on error.
+  // Closes both 'path' given to Open() and the kernel path.
+  int Close() override;
+
+  // Open the target and source (if delta payload) file descriptors for the
+  // |current_partition_|. The manifest needs to be already parsed for this to
+  // work. Returns whether the required file descriptors were successfully open.
+  bool OpenCurrentPartition();
+
+  // Closes the current partition file descriptors if open. Returns 0 on success
+  // or -errno on error.
+  int CloseCurrentPartition();
+
+  // Returns |true| only if the manifest has been processed and it's valid.
+  bool IsManifestValid();
+
+  // Verifies the downloaded payload against the signed hash included in the
+  // payload, against the update check hash (which is in base64 format)  and
+  // size using the public key and returns ErrorCode::kSuccess on success, an
+  // error code on failure.  This method should be called after closing the
+  // stream. Note this method skips the signed hash check if the public key is
+  // unavailable; it returns ErrorCode::kSignedDeltaPayloadExpectedError if the
+  // public key is available but the delta payload doesn't include a signature.
+  ErrorCode VerifyPayload(const std::string& update_check_response_hash,
+                          const uint64_t update_check_response_size);
+
+  // Converts an ordered collection of Extent objects which contain data of
+  // length full_length to a comma-separated string. For each Extent, the
+  // string will have the start offset and then the length in bytes.
+  // The length value of the last extent in the string may be short, since
+  // the full length of all extents in the string is capped to full_length.
+  // Also, an extent starting at kSparseHole, appears as -1 in the string.
+  // For example, if the Extents are {1, 1}, {4, 2}, {kSparseHole, 1},
+  // {0, 1}, block_size is 4096, and full_length is 5 * block_size - 13,
+  // the resulting string will be: "4096:4096,16384:8192,-1:4096,0:4083"
+  static bool ExtentsToBsdiffPositionsString(
+      const google::protobuf::RepeatedPtrField<Extent>& extents,
+      uint64_t block_size,
+      uint64_t full_length,
+      std::string* positions_string);
+
+  // Returns true if a previous update attempt can be continued based on the
+  // persistent preferences and the new update check response hash.
+  static bool CanResumeUpdate(PrefsInterface* prefs,
+                              std::string update_check_response_hash);
+
+  // Resets the persistent update progress state to indicate that an update
+  // can't be resumed. Performs a quick update-in-progress reset if |quick| is
+  // true, otherwise resets all progress-related update state. Returns true on
+  // success, false otherwise.
+  static bool ResetUpdateProgress(PrefsInterface* prefs, bool quick);
+
+  // Attempts to parse the update metadata starting from the beginning of
+  // |payload|. On success, returns kMetadataParseSuccess. Returns
+  // kMetadataParseInsufficientData if more data is needed to parse the complete
+  // metadata. Returns kMetadataParseError if the metadata can't be parsed given
+  // the payload.
+  MetadataParseResult ParsePayloadMetadata(const brillo::Blob& payload,
+                                           ErrorCode* error);
+
+  void set_public_key_path(const std::string& public_key_path) {
+    public_key_path_ = public_key_path;
+  }
+
+  // Set |*out_offset| to the byte offset where the size of the metadata signature
+  // is stored in a payload. Return true on success, if this field is not
+  // present in the payload, return false.
+  bool GetMetadataSignatureSizeOffset(uint64_t* out_offset) const;
+
+  // Set |*out_offset| to the byte offset at which the manifest protobuf begins
+  // in a payload. Return true on success, false if the offset is unknown.
+  bool GetManifestOffset(uint64_t* out_offset) const;
+
+  // Returns the size of the payload metadata, which includes the payload header
+  // and the manifest. If the header was not yet parsed, returns zero.
+  uint64_t GetMetadataSize() const;
+
+  // If the manifest was successfully parsed, copies it to |*out_manifest_p|.
+  // Returns true on success.
+  bool GetManifest(DeltaArchiveManifest* out_manifest_p) const;
+
+  // Return true if header parsing is finished and no errors occurred.
+  bool IsHeaderParsed() const;
+
+  // Returns the major payload version. If the version was not yet parsed,
+  // returns zero.
+  uint64_t GetMajorVersion() const;
+
+  // Returns the delta minor version. If this value is defined in the manifest,
+  // it returns that value, otherwise it returns the default value.
+  uint32_t GetMinorVersion() const;
+
+ private:
+  friend class DeltaPerformerTest;
+  friend class DeltaPerformerIntegrationTest;
+  FRIEND_TEST(DeltaPerformerTest, BrilloMetadataSignatureSizeTest);
+  FRIEND_TEST(DeltaPerformerTest, BrilloVerifyMetadataSignatureTest);
+  FRIEND_TEST(DeltaPerformerTest, UsePublicKeyFromResponse);
+
+  // Parse and move the update instructions of all partitions into our local
+  // |partitions_| variable based on the version of the payload. Requires the
+  // manifest to be parsed and valid.
+  bool ParseManifestPartitions(ErrorCode* error);
+
+  // Appends up to |*count_p| bytes from |*bytes_p| to |buffer_|, but only to
+  // the extent that the size of |buffer_| does not exceed |max|. Advances
+  // |*cbytes_p| and decreases |*count_p| by the actual number of bytes copied,
+  // and returns this number.
+  size_t CopyDataToBuffer(const char** bytes_p, size_t* count_p, size_t max);
+
+  // If |op_result| is false, emits an error message using |op_type_name| and
+  // sets |*error| accordingly. Otherwise does nothing. Returns |op_result|.
+  bool HandleOpResult(bool op_result, const char* op_type_name,
+                      ErrorCode* error);
+
+  // Logs the progress of downloading/applying an update.
+  void LogProgress(const char* message_prefix);
+
+  // Update overall progress metrics, log as necessary.
+  void UpdateOverallProgress(bool force_log, const char* message_prefix);
+
+  // Verifies that the expected source partition hashes (if present) match the
+  // hashes for the current partitions. Returns true if there are no expected
+  // hashes in the payload (e.g., if it's a new-style full update) or if the
+  // hashes match; returns false otherwise.
+  bool VerifySourcePartitions();
+
+  // Returns true if enough of the delta file has been passed via Write()
+  // to be able to perform a given install operation.
+  bool CanPerformInstallOperation(const InstallOperation& operation);
+
+  // Checks the integrity of the payload manifest. Returns true upon success,
+  // false otherwise.
+  ErrorCode ValidateManifest();
+
+  // Validates that the hash of the blobs corresponding to the given |operation|
+  // matches what's specified in the manifest in the payload.
+  // Returns ErrorCode::kSuccess on match or a suitable error code otherwise.
+  ErrorCode ValidateOperationHash(const InstallOperation& operation);
+
+  // Given the |payload|, verifies that the signed hash of its metadata matches
+  // what's specified in the install plan from Omaha (if present) or the
+  // metadata signature in payload itself (if present). Returns
+  // ErrorCode::kSuccess on match or a suitable error code otherwise. This
+  // method must be called before any part of the metadata is parsed so that a
+  // man-in-the-middle attack on the SSL connection to the payload server
+  // doesn't exploit any vulnerability in the code that parses the protocol
+  // buffer.
+  ErrorCode ValidateMetadataSignature(const brillo::Blob& payload);
+
+  // Returns true on success.
+  bool PerformInstallOperation(const InstallOperation& operation);
+
+  // These perform a specific type of operation and return true on success.
+  bool PerformReplaceOperation(const InstallOperation& operation);
+  bool PerformZeroOrDiscardOperation(const InstallOperation& operation);
+  bool PerformMoveOperation(const InstallOperation& operation);
+  bool PerformBsdiffOperation(const InstallOperation& operation);
+  bool PerformSourceCopyOperation(const InstallOperation& operation);
+  bool PerformSourceBsdiffOperation(const InstallOperation& operation);
+
+  // Extracts the payload signature message from the blob on the |operation| if
+  // the offset matches the one specified by the manifest. Returns whether the
+  // signature was extracted.
+  bool ExtractSignatureMessageFromOperation(const InstallOperation& operation);
+
+  // Extracts the payload signature message from the current |buffer_| if the
+  // offset matches the one specified by the manifest. Returns whether the
+  // signature was extracted.
+  bool ExtractSignatureMessage();
+
+  // Updates the payload hash calculator with the bytes in |buffer_|, also
+  // updates the signed hash calculator with the first |signed_hash_buffer_size|
+  // bytes in |buffer_|. Then discard the content, ensuring that memory is being
+  // deallocated. If |do_advance_offset|, advances the internal offset counter
+  // accordingly.
+  void DiscardBuffer(bool do_advance_offset, size_t signed_hash_buffer_size);
+
+  // Checkpoints the update progress into persistent storage to allow this
+  // update attempt to be resumed after reboot.
+  bool CheckpointUpdateProgress();
+
+  // Primes the required update state. Returns true if the update state was
+  // successfully initialized to a saved resume state or if the update is a new
+  // update. Returns false otherwise.
+  bool PrimeUpdateState();
+
+  // If the Omaha response contains a public RSA key and we're allowed
+  // to use it (e.g. if we're in developer mode), extract the key from
+  // the response and store it in a temporary file and return true. In
+  // the affirmative the path to the temporary file is stored in
+  // |out_tmp_key| and it is the responsibility of the caller to clean
+  // it up.
+  bool GetPublicKeyFromResponse(base::FilePath *out_tmp_key);
+
+  // Update Engine preference store.
+  PrefsInterface* prefs_;
+
+  // Global context of the system.
+  SystemState* system_state_;
+
+  // Install Plan based on Omaha Response.
+  InstallPlan* install_plan_;
+
+  // File descriptor of the source partition. Only set while updating a
+  // partition when using a delta payload.
+  FileDescriptorPtr source_fd_{nullptr};
+
+  // File descriptor of the target partition. Only set while performing the
+  // operations of a given partition.
+  FileDescriptorPtr target_fd_{nullptr};
+
+  // Paths the |source_fd_| and |target_fd_| refer to.
+  std::string source_path_;
+  std::string target_path_;
+
+  // Parsed manifest. Set after enough bytes to parse the manifest were
+  // downloaded.
+  DeltaArchiveManifest manifest_;
+  bool manifest_parsed_{false};
+  bool manifest_valid_{false};
+  uint64_t metadata_size_{0};
+  uint64_t manifest_size_{0};
+  uint32_t metadata_signature_size_{0};
+  uint64_t major_payload_version_{0};
+
+  // Accumulated number of operations per partition. The i-th element is the
+  // sum of the number of operations for all the partitions from 0 to i
+  // inclusive. Valid when |manifest_valid_| is true.
+  std::vector<size_t> acc_num_operations_;
+
+  // The total operations in a payload. Valid when |manifest_valid_| is true,
+  // otherwise 0.
+  size_t num_total_operations_{0};
+
+  // The list of partitions to update as found in the manifest major version 2.
+  // When parsing an older manifest format, the information is converted over to
+  // this format instead.
+  std::vector<PartitionUpdate> partitions_;
+
+  // Index in the list of partitions (|partitions_| member) of the current
+  // partition being processed.
+  size_t current_partition_{0};
+
+  // Index of the next operation to perform in the manifest. The index is linear
+  // on the total number of operation on the manifest.
+  size_t next_operation_num_{0};
+
+  // A buffer used for accumulating downloaded data. Initially, it stores the
+  // payload metadata; once that's downloaded and parsed, it stores data for the
+  // next update operation.
+  brillo::Blob buffer_;
+  // Offset of buffer_ in the binary blobs section of the update.
+  uint64_t buffer_offset_{0};
+
+  // Last |buffer_offset_| value updated as part of the progress update.
+  uint64_t last_updated_buffer_offset_{kuint64max};
+
+  // The block size (parsed from the manifest).
+  uint32_t block_size_{0};
+
+  // Calculates the whole payload file hash, including headers and signatures.
+  HashCalculator payload_hash_calculator_;
+
+  // Calculates the hash of the portion of the payload signed by the payload
+  // signature. This hash skips the metadata signature portion, located after
+  // the metadata and doesn't include the payload signature itself.
+  HashCalculator signed_hash_calculator_;
+
+  // Signatures message blob extracted directly from the payload.
+  brillo::Blob signatures_message_data_;
+
+  // The public key to be used. Provided as a member so that tests can
+  // override with test keys.
+  std::string public_key_path_{constants::kUpdatePayloadPublicKeyPath};
+
+  // The number of bytes received so far, used for progress tracking.
+  size_t total_bytes_received_{0};
+
+  // An overall progress counter, which should reflect both download progress
+  // and the ratio of applied operations. Range is 0-100.
+  unsigned overall_progress_{0};
+
+  // The last progress chunk recorded.
+  unsigned last_progress_chunk_{0};
+
+  // The timeout after which we should force emitting a progress log (constant),
+  // and the actual point in time for the next forced log to be emitted.
+  const base::TimeDelta forced_progress_log_wait_{
+      base::TimeDelta::FromSeconds(kProgressLogTimeoutSeconds)};
+  base::Time forced_progress_log_time_;
+
+  // The payload major payload version supported by DeltaPerformer.
+  uint64_t supported_major_version_{kSupportedMajorPayloadVersion};
+
+  // The delta minor payload version supported by DeltaPerformer.
+  uint32_t supported_minor_version_{kSupportedMinorPayloadVersion};
+
+  DISALLOW_COPY_AND_ASSIGN(DeltaPerformer);
+};
+
+}  // namespace chromeos_update_engine
+
+#endif  // UPDATE_ENGINE_PAYLOAD_CONSUMER_DELTA_PERFORMER_H_