1acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani// 2acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani// Copyright (C) 2017 The Android Open Source Project 3acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani// 4acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani// Licensed under the Apache License, Version 2.0 (the "License"); 5acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani// you may not use this file except in compliance with the License. 6acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani// You may obtain a copy of the License at 7acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani// 8acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani// http://www.apache.org/licenses/LICENSE-2.0 9acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani// 10acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani// Unless required by applicable law or agreed to in writing, software 11acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani// distributed under the License is distributed on an "AS IS" BASIS, 12acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani// See the License for the specific language governing permissions and 14acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani// limitations under the License. 15acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani// 16acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani 17acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani#include "update_engine/payload_consumer/cached_file_descriptor.h" 18acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani 19acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani#include <unistd.h> 20acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani 21acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani#include <algorithm> 22acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani 23acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani#include <base/logging.h> 24acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani 25acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani#include "update_engine/common/utils.h" 26acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani 27acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassaninamespace chromeos_update_engine { 28acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani 29acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassanioff64_t CachedFileDescriptor::Seek(off64_t offset, int whence) { 30acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani // Only support SEEK_SET and SEEK_CUR. I think these two would be enough. If 31acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani // we want to support SEEK_END then we have to figure out the size of the 32acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani // underlying file descriptor each time and it may not be a very good idea. 33acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani CHECK(whence == SEEK_SET || whence == SEEK_CUR); 34acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani off64_t next_offset = whence == SEEK_SET ? offset : offset_ + offset; 35acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani 36acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani if (next_offset != offset_) { 37acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani // We sought somewhere other than what we are now. So we have to flush and 38acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani // move to the new offset. 39acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani if (!FlushCache()) { 40acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani return -1; 41acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani } 42acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani // Then we have to seek there. 43acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani if (fd_->Seek(next_offset, SEEK_SET) < 0) { 44acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani return -1; 45acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani } 46acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani offset_ = next_offset; 47acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani } 48acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani return offset_; 49acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani} 50acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani 51acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassanissize_t CachedFileDescriptor::Write(const void* buf, size_t count) { 52acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani auto bytes = static_cast<const uint8_t*>(buf); 53acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani size_t total_bytes_wrote = 0; 54acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani while (total_bytes_wrote < count) { 55acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani auto bytes_to_cache = 56acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani std::min(count - total_bytes_wrote, cache_.size() - bytes_cached_); 57acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani if (bytes_to_cache > 0) { // Which means |cache_| is still have some space. 58acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani memcpy(cache_.data() + bytes_cached_, 59acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani bytes + total_bytes_wrote, 60acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani bytes_to_cache); 61acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani total_bytes_wrote += bytes_to_cache; 62acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani bytes_cached_ += bytes_to_cache; 63acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani } 64acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani if (bytes_cached_ == cache_.size()) { 65acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani // Cache is full; write it to the |fd_| as long as you can. 66acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani if (!FlushCache()) { 67acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani return -1; 68acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani } 69acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani } 70acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani } 71acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani offset_ += total_bytes_wrote; 72acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani return total_bytes_wrote; 73acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani} 74acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani 75acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassanibool CachedFileDescriptor::Flush() { 76acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani return FlushCache() && fd_->Flush(); 77acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani} 78acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani 79acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassanibool CachedFileDescriptor::Close() { 80acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani offset_ = 0; 81acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani return FlushCache() && fd_->Close(); 82acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani} 83acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani 84acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassanibool CachedFileDescriptor::FlushCache() { 85acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani size_t begin = 0; 86acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani while (begin < bytes_cached_) { 87acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani auto bytes_wrote = fd_->Write(cache_.data() + begin, bytes_cached_ - begin); 88acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani if (bytes_wrote < 0) { 89acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani PLOG(ERROR) << "Failed to flush cached data!"; 90acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani return false; 91acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani } 92acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani begin += bytes_wrote; 93acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani } 94acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani bytes_cached_ = 0; 95acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani return true; 96acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani} 97acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani 98acd7be816579a0c13ac6f746a2555b7c73f95a3bAmin Hassani} // namespace chromeos_update_engine 99