/*
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* Copyright (C) 2019 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 "utility.h"
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#include <stdint.h>
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#include <sys/vfs.h>
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#include <unistd.h>
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#include <android-base/logging.h>
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#include <libfiemap_writer/fiemap_writer.h>
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namespace android {
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namespace fiemap_writer {
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uint64_t DetermineMaximumFileSize(const std::string& file_path) {
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// Create the smallest file possible (one block).
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auto writer = FiemapWriter::Open(file_path, 1);
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if (!writer) {
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return 0;
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}
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uint64_t result = 0;
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switch (writer->fs_type()) {
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case EXT4_SUPER_MAGIC:
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// The minimum is 16GiB, so just report that. If we wanted we could parse the
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// superblock and figure out if 64-bit support is enabled.
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result = 17179869184ULL;
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break;
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case F2FS_SUPER_MAGIC:
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// Formula is from https://www.kernel.org/doc/Documentation/filesystems/f2fs.txt
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// 4KB * (923 + 2 * 1018 + 2 * 1018 * 1018 + 1018 * 1018 * 1018) := 3.94TB.
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result = 4329690886144ULL;
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break;
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case MSDOS_SUPER_MAGIC:
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// 4GB-1, which we want aligned to the block size.
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result = 4294967295;
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result -= (result % writer->block_size());
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break;
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default:
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LOG(ERROR) << "Unknown file system type: " << writer->fs_type();
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break;
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}
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// Close and delete the temporary file.
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writer = nullptr;
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unlink(file_path.c_str());
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return result;
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}
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} // namespace fiemap_writer
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} // namespace android
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