Storage device wrappers¶

Quick example¶

Basic usage of storage wrappers uses the disk device type wrapped in Disk wrapper, and accessing disk and partition information using properties on that object. All partitions are accessible through the object’s partitions attribute, so it is not necessary to separately wrap partition objects (though there is nothing wrong with that).

Example:

>>> devs = list(udev.devices_by_subsystem('block'))
>>> device = storage.Disk(devs[0])
>>> device.bus
u'ata'
>>> device.size
256060514304
>>> device.sectors
500118192
>>> device.part_table_type
u'gpt'
>>> p1 = device.partitions[0]
>>> p1.offset
4097
>>> p1.size
314573312
>>> p1.format
u'vfat'

Module contents¶

class hwd.storage.Disk(dev)¶

Wrapper for pyudev.Device objects of ‘disk’ type.

is_read_only¶: Whether disk is read-only. This evaluates to True if disk is read-only.

is_removable¶

Whether disk is removable. This property evaluates to True if disk is removable. Note that this does not mean disk is USB-attached, and does not necessarily match the common notion of removable devices.

If you wish to know whether a device is USB-attached, check whether the value of the bus property is 'usb'.

part_table_type¶: Partition table type. Evaluates to either 'dos' or 'gpt'.

partitions¶: Iterable containing disk’s partition objects. Objects in the iterable are Partition instances.

sectors¶: Disk size in sectors. If for some reason, this information is not available, this property evaluates to -1.

size¶: Disk capacity in bytes. This value is obtained by multiplying sector size by 512.

uuid¶: Partition table UUID. Note that UUIDs for different partition table types have different fomats.

class hwd.storage.Fstat(total, used, free, pct_used, pct_free)¶

free¶: Alias for field number 2

pct_free¶: Alias for field number 4

pct_used¶: Alias for field number 3

total¶: Alias for field number 0

used¶: Alias for field number 1

class hwd.storage.Mountable¶

Mixing providing interfaces for mountable storage devices.

mount_points¶: Iterator of partition’s mount points obtained by reading /proc/mounts. Returns empty list if /proc/mounts is not readable or if there are no mount points.

size¶: Subclasses using this mixin must implement their own size property which returns the total capacity in bytes.

stat¶: Return disk usage information for the partition in Fstat format. If disk usage information is not available, then None is returned. Disk usage information is only available for regular filesystems that are mounted.

class hwd.storage.MtabEntry(dev, mdir, fstype, opts, cfreq, cpass)¶

cfreq¶: Alias for field number 4

cpass¶: Alias for field number 5

dev¶: Alias for field number 0

fstype¶: Alias for field number 2

mdir¶: Alias for field number 1

opts¶: Alias for field number 3

class hwd.storage.Partition(dev, disk=None)¶

Wrapper for pyudev.Device objects of ‘partition’ type.

As with all wrappers, this class takes dev as its first argument. The optional disk argument can be passed, and is stored as the disk property. This is mostly used by Disk class to maintain a refrence to itself.

format¶: Fiesystem type. This evaluates to any number of supported file system types such as 'ext4' or 'vfat'.

Note

Extended partitions will have this property evaluate to None.

is_extended¶: Whether partition is extended.

label¶: Volume label. This property evaluates to None if no volume label is not set on a partition.

number¶: Partition number. This specifies a position of the partition in the partition table. If the value is not known for some reason, this property evaluates to -1.

offset¶: Partition offset in sectors. If this information is not available for some reason, it evaluates to -1.

parent_class¶: alias of Disk

part_type¶: Partition type ID. This is expressed in hex string. Note that this is not the same as filesystem type which is available through the part_type property.

scheme¶: Partition entry scheme. This evaluates to either 'dos' or 'gpt'.

sectors¶: Partition size in sectors. If this information is not available for some reason, it evaluates to -1.

size¶: Partition size in bytes. This value is obtained by multiplying the sector size by 512.

usage¶: Filesystem usage (purpose). In most cases this should evaluate to 'filesystem'. In some cases (e.g., swap partition), it may evaluate to 'other' or some other value.

uuid¶: Filesystem UUID. Note that this is not the same as the partition UUID (which is not available through this wrapper, other than directly accessing the underlying pyudev.Device object).

class hwd.storage.PartitionBase(dev, disk=None)¶: Base class for all partition devices. This class encapsulates the base functionality for all mountable partitions. It takes disk as an optional argument, and allows access to parent device from the partition devices.

class hwd.storage.UbiContainer(dev)¶

Wrapper for pyudev.Device objects of the ‘ubi’ subsytem.

The ‘ubi’ subsystem has two types of devices. The parent devices serve as containers for the actual volumes. This class is meant to be used by containers, rather than volumes.

This class mainly exists to facilitate the PartitionBase API, specifically the API that allows access to parent device.

class hwd.storage.UbiVolume(dev, disk=None)¶

Wrapper for pyudev.Device objects of the ‘ubi’ subsytem.

The ‘ubi’ subsystem has two types of devices. The parent devices serve as containers for the actual volumes. This class is meant to be used by volumes, rather than their parent devices.

aliases¶: Aliases for UBI volume. This propery evaluates to device node itself plus the 'ubi${INDEX}:${LABEL}' string. The latter is used to identify the device in /proc/mounts table, and is not really an alias.

label¶: UBI volume name. For compatibility with Partition API, we name this property ‘label’.

parent_class¶: alias of UbiContainer

sectors¶: Simulated number of sectors derived from volume size. This property is provided for compatibility with Partition API.

Warning

The concept does not really apply to UBI volumes, so it’s best to not rely on the value of this property.

size¶: Volume capacity in bytes. This property evaluates to -1 if size information is not available for any reason.

hwd.storage.mounts()¶: Iterator yielding mount points that appear in /proc/mounts. If /proc/mounts is not readable or does not exist, this function raises an exception.