Find device-dependent disk stats file, and skip disk stats if not available.

metrics_daemon.cc

 // Copyright (c) 2010 The Chromium OS 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 "metrics_daemon.h"
 
 #include <fcntl.h>
 #include <string.h>
 
 #include <base/file_util.h>
@@ skipping 128 matching lines @@
 const char* MetricsDaemon::kSessionStates_[] = {
 #define STATE(name, capname) #name,
 #include "session_states.h"
 };
 
 MetricsDaemon::MetricsDaemon()
     : power_state_(kUnknownPowerState),
       session_state_(kUnknownSessionState),
       user_active_(false),
       usemon_interval_(0),
-      usemon_source_(NULL),
-      diskstats_path_(NULL) {}
+      usemon_source_(NULL) {}
 
 MetricsDaemon::~MetricsDaemon() {
   DeleteFrequencyCounters();
 }
 
 void MetricsDaemon::DeleteFrequencyCounters() {
   for (FrequencyCounters::iterator i = frequency_counters_.begin();
        i != frequency_counters_.end(); ++i) {
     delete i->second;
     i->second = NULL;
@@ skipping 47 matching lines @@
       chromeos_metrics::kSecondsPerWeek :
       chromeos_metrics::kSecondsPerDay;
   new_counter->Init(
       static_cast<chromeos_metrics::TaggedCounterInterface*>(
           reporter.release()),
       cycle_duration);
   frequency_counters_[histogram_name] = new_counter.release();
 }
 
 void MetricsDaemon::Init(bool testing, MetricsLibraryInterface* metrics_lib,
-                         const char* diskstats_path) {
+                         string diskstats_path) {
   testing_ = testing;
   DCHECK(metrics_lib != NULL);
   metrics_lib_ = metrics_lib;
   chromeos_metrics::TaggedCounterReporter::
       SetMetricsLibraryInterface(metrics_lib);
 
   static const char kDailyUseRecordFile[] = "/var/log/metrics/daily-usage";
   daily_use_.reset(new chromeos_metrics::TaggedCounter());
   daily_use_->Init(kDailyUseRecordFile, &ReportDailyUse, this);
 
   ConfigureCrashIntervalReporter(kMetricKernelCrashIntervalName,
                                  &kernel_crash_interval_);
   ConfigureCrashIntervalReporter(kMetricUncleanShutdownIntervalName,
                                  &unclean_shutdown_interval_);
   ConfigureCrashIntervalReporter(kMetricUserCrashIntervalName,
                                  &user_crash_interval_);
 
   DeleteFrequencyCounters();
   ConfigureCrashFrequencyReporter(kMetricAnyCrashesDailyName);
   ConfigureCrashFrequencyReporter(kMetricAnyCrashesWeeklyName);
   ConfigureCrashFrequencyReporter(kMetricKernelCrashesDailyName);
   ConfigureCrashFrequencyReporter(kMetricKernelCrashesWeeklyName);
   ConfigureCrashFrequencyReporter(kMetricUncleanShutdownsDailyName);
   ConfigureCrashFrequencyReporter(kMetricUncleanShutdownsWeeklyName);
   ConfigureCrashFrequencyReporter(kMetricUserCrashesDailyName);
   ConfigureCrashFrequencyReporter(kMetricUserCrashesWeeklyName);
 
-  diskstats_path_ = diskstats_path;
-  DiskStatsReporterInit();
+  // Don't attempt to collect disk stats if there is no disk stats file.
+  if (!diskstats_path.empty()) {
+    diskstats_path_ = diskstats_path;
+    DiskStatsReporterInit();
+  }
 
   // Don't setup D-Bus and GLib in test mode.
   if (testing)
     return;
 
   g_thread_init(NULL);
   g_type_init();
   dbus_g_thread_init();
 
   DBusError error;
@@ skipping 276 matching lines @@
     return;
   }
   g_timeout_add_seconds(wait, DiskStatsCallbackStatic, this);
 }
 
 void MetricsDaemon::DiskStatsReadStats(long int* read_sectors,
                                        long int* write_sectors) {
   int nchars;
   int nitems;
   char line[200];
-  int file = HANDLE_EINTR(open(diskstats_path_, O_RDONLY));
+  int file = HANDLE_EINTR(open(diskstats_path_.c_str(), O_RDONLY));
   if (file < 0) {
     PLOG(WARNING) << "cannot open " << diskstats_path_;
     return;
   }
   nchars = HANDLE_EINTR(read(file, line, sizeof(line)));
   if (nchars < 0) {
     PLOG(WARNING) << "cannot read from " << diskstats_path_;
   } else {
     LOG_IF(WARNING, nchars == sizeof(line)) << "line too long in "
                                             << diskstats_path_;
@@ skipping 72 matching lines @@
                      kMetricDailyUseTimeMax,
                      kMetricDailyUseTimeBuckets);
 }
 
 void MetricsDaemon::SendMetric(const string& name, int sample,
                                int min, int max, int nbuckets) {
   DLOG(INFO) << "received metric: " << name << " " << sample << " "
              << min << " " << max << " " << nbuckets;
   metrics_lib_->SendToUMA(name, sample, min, max, nbuckets);
 }