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- // Copyright 2015 The Chromium Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style license that can be
- // found in the LICENSE file.
- #include "components/metrics/drive_metrics_provider.h"
- #include <linux/kdev_t.h> // For MAJOR()/MINOR().
- #include <sys/stat.h>
- #include <string>
- #include "base/files/file.h"
- #include "base/files/file_path.h"
- #include "base/files/file_util.h"
- #include "base/strings/string_util.h"
- #include "base/strings/stringprintf.h"
- #include "build/build_config.h"
- namespace metrics {
- namespace {
- // See http://www.kernel.org/doc/Documentation/devices.txt for more info.
- const int kFirstScsiMajorNumber = 8;
- const int kPartitionsPerScsiDevice = 16;
- const char kRotationalFormat[] = "/sys/block/sd%c/queue/rotational";
- } // namespace
- // static
- bool DriveMetricsProvider::HasSeekPenalty(const base::FilePath& path,
- bool* has_seek_penalty) {
- base::File file(path, base::File::FLAG_OPEN | base::File::FLAG_READ);
- if (!file.IsValid())
- return false;
- struct stat path_stat;
- int error = fstat(file.GetPlatformFile(), &path_stat);
- if (error < 0 || MAJOR(path_stat.st_dev) != kFirstScsiMajorNumber) {
- // TODO(dbeam): support more SCSI major numbers (e.g. /dev/sdq+) and LVM?
- return false;
- }
- char sdX = 'a' + MINOR(path_stat.st_dev) / kPartitionsPerScsiDevice;
- std::string rotational_path = base::StringPrintf(kRotationalFormat, sdX);
- std::string rotates;
- if (!base::ReadFileToString(base::FilePath(rotational_path), &rotates))
- return false;
- *has_seek_penalty = rotates.substr(0, 1) == "1";
- return true;
- }
- } // namespace metrics
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