Disable automatic update checks if booting from a removable device.

utils.h

 // 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.
 
 #ifndef CHROMEOS_PLATFORM_UPDATE_ENGINE_UTILS_H__
 #define CHROMEOS_PLATFORM_UPDATE_ENGINE_UTILS_H__
 
 #include <errno.h>
 #include <algorithm>
 #include <set>
@@ skipping 66 matching lines @@
 // in the dirname param. Returns TRUE on success. dirname must not be NULL.
 bool MakeTempDirectory(const std::string& dirname_template,
                        std::string* dirname);
 
 // Deletes a directory and all its contents synchronously. Returns true
 // on success. This may be called with a regular file--it will just unlink it.
 // This WILL cross filesystem boundaries.
 bool RecursiveUnlinkDir(const std::string& path);
 
 // Returns the root device for a partition. For example,
-// RootDevice("/dev/sda3") returns "/dev/sda".
+// RootDevice("/dev/sda3") returns "/dev/sda". Returns an empty string
+// if the input device is not of the "/dev/xyz" form.
 std::string RootDevice(const std::string& partition_device);
 
 // Returns the partition number, as a string, of partition_device. For example,
-// PartitionNumber("/dev/sda3") return "3".
+// PartitionNumber("/dev/sda3") returns "3".
 std::string PartitionNumber(const std::string& partition_device);
 
+// Returns the sysfs block device for a root block device. For
+// example, SysfsBlockDevice("/dev/sda") returns
+// "/sys/block/sda". Returns an empty string if the input device is
+// not of the "/dev/xyz" form.
+std::string SysfsBlockDevice(const std::string& device);
+
+// Returns true if the root |device| (e.g., "/dev/sdb") is known to be
+// removable, false otherwise.
+bool IsRemovableDevice(const std::string& device);
+
 // Synchronously mount or unmount a filesystem. Return true on success.
 // Mounts as ext3 with default options.
 bool MountFilesystem(const std::string& device, const std::string& mountpoint,
                      unsigned long flags);
 bool UnmountFilesystem(const std::string& mountpoint);
 
 enum BootLoader {
   BootLoader_SYSLINUX = 0,
   BootLoader_CHROME_FIRMWARE = 1
 };
@@ skipping 196 matching lines @@
     bool _success = (_x);                                                      \
     if (!_success) {                                                           \
       LOG(ERROR) << #_x " failed.";                                            \
       return;                                                                  \
     }                                                                          \
   } while (0)
 
 
 
 #endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_UTILS_H__