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