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1 // Copyright 2015 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #include "chrome/browser/metrics/drive_metrics_provider.h" | |
6 | |
7 #include <linux/kdev_t.h> // For MAJOR()/MINOR(). | |
8 #include <sys/stat.h> | |
9 #include <string> | |
10 | |
11 #include "base/basictypes.h" | |
12 #include "base/files/file.h" | |
13 #include "base/files/file_path.h" | |
14 #include "base/files/file_util.h" | |
15 #include "base/strings/stringprintf.h" | |
16 | |
17 #if defined(OS_CHROMEOS) | |
18 #include "base/sys_info.h" | |
19 #endif | |
20 | |
21 namespace { | |
22 | |
23 // See http://www.kernel.org/doc/Documentation/devices.txt for more info. | |
24 const int kFirstScsiMajorNumber = 8; | |
25 const char kRotationalFormat[] = "/sys/block/sd%c/queue/rotational"; | |
26 | |
27 } // namespace | |
28 | |
29 // static | |
30 bool DriveMetricsProvider::HasSeekPenalty(const base::FilePath& path, | |
31 bool* has_seek_penalty) { | |
32 #if defined(OS_CHROMEOS) | |
33 std::string board = base::SysInfo::GetLsbReleaseBoard(); | |
34 if (board != "unknown" && board != "parrot") { | |
35 // All ChromeOS devices have SSDs. Except some parrots. | |
36 *has_seek_penalty = false; | |
37 return true; | |
38 } | |
39 #endif | |
40 | |
41 base::File file(path, base::File::FLAG_OPEN | base::File::FLAG_READ); | |
42 if (!file.IsValid()) | |
43 return false; | |
44 | |
45 struct stat path_stat; | |
46 int error = fstat(file.GetPlatformFile(), &path_stat); | |
47 if (error < 0 || MAJOR(path_stat.st_dev) != kFirstScsiMajorNumber) { | |
48 // TODO(dbeam): support more SCSI major numbers (e.g. /dev/sdq+) and LVM? | |
49 return false; | |
50 } | |
51 | |
52 char sdX = 'a' + MINOR(path_stat.st_dev) / 16; | |
Lei Zhang
2015/04/03 23:06:47
Can you mention what the 16 is?
Dan Beam
2015/04/03 23:55:45
Done.
| |
53 std::string rotational = base::StringPrintf(kRotationalFormat, sdX); | |
Lei Zhang
2015/04/03 23:06:47
nit: rotational_path
Dan Beam
2015/04/03 23:55:45
Done.
| |
54 std::string rotates; | |
55 if (!base::ReadFileToString(base::FilePath(rotational), &rotates)) | |
56 return false; | |
57 | |
58 *has_seek_penalty = rotates.substr(0, 1) == "1"; | |
59 return true; | |
60 } | |
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