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 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
