//
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// Copyright (C) 2018 The Android Open Source Project
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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#include "update_engine/payload_consumer/mount_history.h"
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#include <inttypes.h>
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#include <string>
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#include <vector>
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#include <base/logging.h>
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#include <base/time/time.h>
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#include "update_engine/common/utils.h"
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namespace chromeos_update_engine {
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void LogMountHistory(const FileDescriptorPtr blockdevice_fd) {
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static constexpr ssize_t kBlockSize = 4096;
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if (blockdevice_fd == nullptr) {
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return;
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}
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brillo::Blob block0_buffer(kBlockSize);
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ssize_t bytes_read;
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if (!utils::PReadAll(
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blockdevice_fd, block0_buffer.data(), kBlockSize, 0, &bytes_read)) {
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LOG(WARNING) << "PReadAll failed";
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return;
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}
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if (bytes_read != kBlockSize) {
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LOG(WARNING) << "Could not read an entire block";
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return;
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}
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// https://ext4.wiki.kernel.org/index.php/Ext4_Disk_Layout
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// Super block starts from block 0, offset 0x400
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// 0x2C: len32 Mount time
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// 0x30: len32 Write time
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// 0x34: len16 Number of mounts since the last fsck
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// 0x38: len16 Magic signature 0xEF53
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time_t mount_time =
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*reinterpret_cast<uint32_t*>(&block0_buffer[0x400 + 0x2C]);
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uint16_t mount_count =
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*reinterpret_cast<uint16_t*>(&block0_buffer[0x400 + 0x34]);
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uint16_t magic = *reinterpret_cast<uint16_t*>(&block0_buffer[0x400 + 0x38]);
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if (magic == 0xEF53) {
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if (mount_count > 0) {
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LOG(WARNING) << "Device was remounted R/W " << mount_count << " times. "
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<< "Last remount happened on "
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<< base::Time::FromTimeT(mount_time) << ".";
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}
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}
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}
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} // namespace chromeos_update_engine
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