Populate disk information from udev to disk manager.

udev-device.cc

+// Copyright (c) 2011 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 <base/string_number_conversions.h>
+#include <base/string_util.h>
+#include <libudev.h>
+#include <sys/statvfs.h>
+#include <fcntl.h>
+#include <fstream>
+
+#include "udev-device.h"
+
+namespace cros_disks {
+
+UdevDevice::UdevDevice(struct udev_device *dev)
+    : dev_(dev) {
+
+  CHECK(dev_) << "Invalid udev device";
+  udev_device_ref(dev_);
+}
+
+UdevDevice::~UdevDevice() {
+  udev_device_unref(dev_);
+}
+
+bool UdevDevice::IsValueBooleanTrue(const char *value) const {
+  return value && strcmp(value, "1") == 0;
+}
+
+std::string UdevDevice::GetAttribute(const char *key) const {
+  const char *value = udev_device_get_sysattr_value(dev_, key);
+  return (value) ? value : "";
+}
+
+bool UdevDevice::IsAttributeTrue(const char *key) const {
+  const char *value = udev_device_get_sysattr_value(dev_, key);
+  return IsValueBooleanTrue(value);
+}
+
+bool UdevDevice::HasAttribute(const char *key) const {
+  const char *value = udev_device_get_sysattr_value(dev_, key);
+  return value != NULL;
+}
+
+std::string UdevDevice::GetProperty(const char *key) const {
+  const char *value = udev_device_get_property_value(dev_, key);
+  return (value) ? value : "";
+}
+
+bool UdevDevice::IsPropertyTrue(const char *key) const {
+  const char *value = udev_device_get_property_value(dev_, key);
+  return IsValueBooleanTrue(value);
+}
+
+bool UdevDevice::HasProperty(const char *key) const {
+  const char *value = udev_device_get_property_value(dev_, key);
+  return value != NULL;
+}
+
+void UdevDevice::GetSizeInfo(uint64 *total_size, uint64 *remaining_size) const {
+  const char *dev_file = udev_device_get_devnode(dev_);
+
+  struct statvfs stat;
+  bool stat_available = (statvfs(dev_file, &stat) == 0);
+
+  if (total_size) {
+    *total_size = (stat_available) ? (stat.f_blocks * stat.f_frsize) : 0;
+    const char *partition_size = udev_device_get_property_value(dev_,
+            "UDISKS_PARTITION_SIZE");
+    int64 size = 0;
+    if (partition_size) {
+      base::StringToInt64(partition_size, &size);
+      *total_size = size;
+    } else {
+      const char *size_attr = udev_device_get_sysattr_value(dev_, "size");
+      if (size_attr) {
+        base::StringToInt64(size_attr, &size);
+        *total_size = size;
+      }
+    }
+  }
+
+  if (remaining_size)
+    *remaining_size = (stat_available) ? (stat.f_bfree * stat.f_frsize) : 0;
+}
+
+bool UdevDevice::IsMediaAvailable() const {
+  bool is_media_available = true;
+  if (IsAttributeTrue("removable")) {
+    if (IsPropertyTrue("ID_CDROM")) {
+      is_media_available = IsPropertyTrue("ID_CDROM_MEDIA");
+    } else {
+      const char *dev_file = udev_device_get_devnode(dev_);
+      int fd = open(dev_file, O_RDONLY);
+      if (fd < 0) {
+        is_media_available = true;
+      } else {
+        close(fd);
+      }
+    }
+  }
+  return is_media_available;
+}
+
+std::vector<std::string> UdevDevice::GetMountedPaths() const {

[rtc, 2011/04/12 21:12:01]

It might be good to pass data into the function so that the parsing could be
tested easily in a unit-test. 

[Ben Chan, 2011/04/12 21:18:46]

How about splitting the function into two?

std::vector<std::string> UdevDevice::ParseMountedPaths(std::istream& stream)
const;

std::vector<std::string> UdevDevice::GetMountedPaths() const {
  std::ifstream fs("/proc/mounts");
  ...
  return ParseMountedPaths(fs);
}

+  const std::string dev_file = udev_device_get_devnode(dev_);
+  std::vector<std::string> mounted_paths;
+  std::ifstream fs("/proc/mounts");
+  if (fs.is_open()) {
+    std::string line;
+    while (std::getline(fs, line)) {
+      std::vector<std::string> tokens;
+      SplitString(line, ' ', &tokens);
+      if (tokens.size() >= 2) {
+        if (tokens[0] == dev_file)
+          mounted_paths.push_back(tokens[1]);
+      }
+    }
+  }
+  return mounted_paths;
+}
+
+Disk UdevDevice::ToDisk() const {
+  Disk disk;
+
+  disk.set_is_read_only(IsAttributeTrue("ro"));
+  disk.set_is_drive(HasAttribute("range"));
+  disk.set_is_rotational(HasProperty("ID_ATA_ROTATION_RATE_RPM"));
+  disk.set_is_optical_disk(IsPropertyTrue("ID_CDROM"));
+  disk.set_is_hidden(IsPropertyTrue("UDISKS_PRESENTATION_HIDE"));
+  disk.set_is_media_available(IsMediaAvailable());
+  disk.set_drive_model(GetProperty("ID_MODEL"));
+  disk.set_label(GetProperty("ID_FS_LABEL"));
+  disk.set_native_path(udev_device_get_syspath(dev_));
+
+  const char *dev_file = udev_device_get_devnode(dev_);
+  disk.set_device_file(dev_file);
+
+  std::vector<std::string> mounted_paths = GetMountedPaths();
+  disk.set_is_mounted(!mounted_paths.empty());
+  disk.set_mount_path(mounted_paths[0]); //TODO(benchan): multiple paths
+
+  uint64 total_size, remaining_size;
+  GetSizeInfo(&total_size, &remaining_size);
+  disk.set_device_capacity(total_size);
+  disk.set_bytes_remaining(remaining_size);
+
+  return disk;
+}
+
+} // namespace cros_disks