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
28 using std::min;
29
30 namespace chromeos_update_engine {
31
Write(const void * bytes,size_t count)32 bool 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