Find device-dependent disk stats file, and skip disk stats if not available.
Change-Id: I03afb85e3357dd4c2cf5effd98b194c71d77c71d
BUG=12171
TEST=unit tested
Review URL: http://codereview.chromium.org/6541007
diff --git a/metrics/metrics_daemon_main.cc b/metrics/metrics_daemon_main.cc
index 899256c..1ee0611 100644
--- a/metrics/metrics_daemon_main.cc
+++ b/metrics/metrics_daemon_main.cc
@@ -3,20 +3,44 @@
// found in the LICENSE file.
+#include <base/logging.h>
+#include <base/string_util.h>
#include <gflags/gflags.h>
+#include <rootdev/rootdev.h>
#include "metrics_daemon.h"
DEFINE_bool(daemon, true, "run as daemon (use -nodaemon for debugging)");
-// Path to disk stats. This may be system dependent.
-const char kMetricsMainDiskStatsPath[] = "/sys/class/block/sda/stat";
+// Return the path to the disk stats in the sysfs.
+static
+const std::string MetricsMainDiskStatsPath() {
+ char dev_path_cstr[PATH_MAX];
+ std::string dev_prefix = "/dev/";
+ std::string dev_path;
+ std::string dev_name;
+
+ int ret = rootdev(dev_path_cstr, sizeof(dev_path_cstr), true, true);
+ if (ret != 0) {
+ LOG(WARNING) << "error " << ret << " determining root device";
+ return "";
+ }
+ dev_path = dev_path_cstr;
+ // Check that rootdev begins with "/dev/".
+ if (!StartsWithASCII(dev_path, dev_prefix, false)) {
+ LOG(WARNING) << "unexpected root device " << dev_path;
+ return "";
+ }
+ // Get the device name, e.g. "sda" from "/dev/sda".
+ dev_name = dev_path.substr(dev_prefix.length());
+ return "/sys/class/block/" + dev_name + "/stat";
+}
int main(int argc, char** argv) {
google::ParseCommandLineFlags(&argc, &argv, true);
MetricsLibrary metrics_lib;
metrics_lib.Init();
MetricsDaemon daemon;
- daemon.Init(false, &metrics_lib, kMetricsMainDiskStatsPath);
+ daemon.Init(false, &metrics_lib, MetricsMainDiskStatsPath());
daemon.Run(FLAGS_daemon);
}