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