// 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 // For MAJOR()/MINOR(). #include #include #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