1//
2// Copyright (C) 2009 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#include "update_engine/payload_consumer/extent_writer.h"
18
19#include <errno.h>
20#include <sys/types.h>
21#include <unistd.h>
22
23#include <algorithm>
24
25#include "update_engine/common/utils.h"
26#include "update_engine/payload_consumer/payload_constants.h"
27
28using std::min;
29
30namespace chromeos_update_engine {
31
32bool DirectExtentWriter::Write(const void* bytes, size_t count) {
33  if (count == 0)
34    return true;
35  const char* c_bytes = reinterpret_cast<const char*>(bytes);
36  size_t bytes_written = 0;
37  while (count - bytes_written > 0) {
38    TEST_AND_RETURN_FALSE(next_extent_index_ < extents_.size());
39    uint64_t bytes_remaining_next_extent =
40        extents_[next_extent_index_].num_blocks() * block_size_ -
41        extent_bytes_written_;
42    CHECK_NE(bytes_remaining_next_extent, static_cast<uint64_t>(0));
43    size_t bytes_to_write =
44        static_cast<size_t>(min(static_cast<uint64_t>(count - bytes_written),
45                                bytes_remaining_next_extent));
46    TEST_AND_RETURN_FALSE(bytes_to_write > 0);
47
48    if (extents_[next_extent_index_].start_block() != kSparseHole) {
49      const off64_t offset =
50          extents_[next_extent_index_].start_block() * block_size_ +
51          extent_bytes_written_;
52      TEST_AND_RETURN_FALSE_ERRNO(fd_->Seek(offset, SEEK_SET) !=
53                                  static_cast<off64_t>(-1));
54      TEST_AND_RETURN_FALSE(
55          utils::WriteAll(fd_, c_bytes + bytes_written, bytes_to_write));
56    }
57    bytes_written += bytes_to_write;
58    extent_bytes_written_ += bytes_to_write;
59    if (bytes_remaining_next_extent == bytes_to_write) {
60      // We filled this extent
61      CHECK_EQ(extent_bytes_written_,
62               extents_[next_extent_index_].num_blocks() * block_size_);
63      // move to next extent
64      extent_bytes_written_ = 0;
65      next_extent_index_++;
66    }
67  }
68  return true;
69}
70
71}  // namespace chromeos_update_engine
72