Detect seek penalties on Linux/ChromeOS.

This wont work any time some fancy /dev setup is going on.

R=thestig@chromium.org
BUG=463209
NOTRY=true

Review URL: https://codereview.chromium.org/1057093003

Cr-Commit-Position: refs/heads/master@{#323865}
(cherry picked from commit 022b19cb4b2f4e7a0f56ad92198b050b76e4415f)

Review URL: https://codereview.chromium.org/1065793002

Cr-Commit-Position: refs/branch-heads/2357@{#14}
Cr-Branched-From: 59d4494849b405682265ed5d3f5164573b9a939b-refs/heads/master@{#323860}

4 files changed, 74 insertions, 9 deletions

diff --git a/chrome/browser/metrics/drive_metrics_provider.cc b/chrome/browser/metrics/drive_metrics_provider.cc
index 5873583..4b88849 100644
--- a/chrome/browser/metrics/drive_metrics_provider.cc
+++ b/chrome/browser/metrics/drive_metrics_provider.cc
@@ -40,15 +40,6 @@ void DriveMetricsProvider::GetDriveMetrics(const base::Closure& done) {
 DriveMetricsProvider::SeekPenaltyResponse::SeekPenaltyResponse()
     : success(false) {}
 
-#if !(defined(OS_WIN) || defined(OS_ANDROID) || defined(OS_IOS))
-// static
-bool DriveMetricsProvider::HasSeekPenalty(const base::FilePath& path,
-                                          bool* has_seek_penalty) {
-  // TODO(dbeam): implement on more platforms.
-  return false;
-}
-#endif
-
 // static
 DriveMetricsProvider::DriveMetrics
 DriveMetricsProvider::GetDriveMetricsOnFileThread() {
diff --git a/chrome/browser/metrics/drive_metrics_provider_linux.cc b/chrome/browser/metrics/drive_metrics_provider_linux.cc
new file mode 100644
index 0000000..93c37a0
--- /dev/null
+++ b/chrome/browser/metrics/drive_metrics_provider_linux.cc
@@ -0,0 +1,60 @@
+// 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 "chrome/browser/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/stringprintf.h"
+
+#if defined(OS_CHROMEOS)
+#include "base/sys_info.h"
+#endif
+
+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) {
+#if defined(OS_CHROMEOS)
+  std::string board = base::SysInfo::GetLsbReleaseBoard();
+  if (board != "unknown" && board != "parrot") {
+    // All ChromeOS devices have SSDs. Except some parrots.
+    *has_seek_penalty = false;
+    return true;
+  }
+#endif
+
+  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;
+}
diff --git a/chrome/browser/metrics/drive_metrics_provider_mac.mm b/chrome/browser/metrics/drive_metrics_provider_mac.mm
new file mode 100644
index 0000000..ff98485
--- /dev/null
+++ b/chrome/browser/metrics/drive_metrics_provider_mac.mm
@@ -0,0 +1,12 @@
+// 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 "chrome/browser/metrics/drive_metrics_provider.h"
+
+// static
+bool DriveMetricsProvider::HasSeekPenalty(const base::FilePath& path,
+                                          bool* has_seek_penalty) {
+  // TODO(dbeam): implement.
+  return false;
+}
diff --git a/chrome/chrome_browser.gypi b/chrome/chrome_browser.gypi
index e3fa309..7b4811d 100644
--- a/chrome/chrome_browser.gypi
+++ b/chrome/chrome_browser.gypi
@@ -1735,6 +1735,8 @@
       'browser/metrics/drive_metrics_provider.cc',
       'browser/metrics/drive_metrics_provider_android.cc',
       'browser/metrics/drive_metrics_provider_ios.mm',
+      'browser/metrics/drive_metrics_provider_linux.cc',
+      'browser/metrics/drive_metrics_provider_mac.mm',
       'browser/metrics/drive_metrics_provider_win.cc',
       'browser/metrics/drive_metrics_provider.h',
       'browser/metrics/field_trial_synchronizer.cc',