phpman > man > udisks(8)

UDISKS(8)                               System Administration                              UDISKS(8)



NAME
       udisks - Disk Manager

DESCRIPTION
       udisks provides interfaces to enumerate and perform operations on disks and storage devices.
       Any application (including unprivileged ones) can access the udisksd(8) daemon via the name
       org.freedesktop.UDisks2 on the system message bus[1]. In addition to the D-Bus API, a
       library, libudisks2 is also provided. This library can be used from C/C++ and any high-level
       language with GObjectIntrospection[2] support such as Javascript and Python. udisks is only
       indirectly involved in what devices and objects are shown in the user interface.

ACCESS CONTROL
       By default, logged-in users in active log-in sessions are permitted to perform operations
       (for example, mounting, unlocking or modifying) on devices attached to the seat their session
       is on. Access-control is fine-grained and based on polkit(8), see the “Authorization Checks”
       chapter in the udisks documentation for more information. Note that the x-udisks-auth option
       can be used in the /etc/fstab and /etc/crypttab files to specify that additional
       authorization is required to mount resp. unlock the device (typically requiring the user to
       authenticate as an administrator).

DRIVE CONFIGURATION
       At start-up and when a drive is connected, udisksd(8) will apply configuration stored in the
       file /etc/udisks2/IDENTIFIER.conf where IDENTIFIER is the value of the Drive:Id property for
       the drive. If the file changes on disk its new contents will also be applied to the drive.
       Typically, users or administrators will never need to edit drive configuration files as they
       are effectively managed through graphical applications such as gnome-disks(1). Manually
       editing configuration files is however supported — the file format is a simple .ini-like
       format (see the Desktop Entry Specification[3] for the exact syntax). New groups and keys may
       be added in the future.

   ATA group
       The ATA group is for settings that apply to drives using the ATA command-set. The following
       keys are supported:

       StandbyTimeout
           The standby timeout. A value of zero means "timeouts are disabled": the device will not
           automatically enter standby mode. Values from 1 to 240 specify multiples of 5 seconds,
           yielding timeouts from 5 seconds to 20 minutes. Values from 241 to 251 specify from 1 to
           11 units of 30 minutes, yielding timeouts from 30 minutes to 5.5 hours. A value of 252
           signifies a timeout of 21 minutes. A value of 253 sets a vendor-defined timeout period
           between 8 and 12 hours, and the value 254 is reserved. 255 is interpreted as 21 minutes
           plus 15 seconds. Note that some older drives may have very different interpretations of
           these values. This is similar to the -S option in hdparm(8).

       APMLevel
           The Advanced Power Management level. A low value means aggressive power management and a
           high value means better performance. Possible settings range from values 1 through 127
           (which permit spin-down), and values 128 through 254 (which do not permit spin-down). The
           highest degree of power management is attained with a setting of 1, and the highest I/O
           performance with a setting of 254. A value of 255 can be used to disable Advanced Power
           Management altogether on the drive (not all drives support disabling it, but most do).
           This is similar to the -B option in hdparm(8).

       AAMLevel
           The Automatic Acoustic Management level. Most modern harddisk drives have the ability to
           speed down the head movements to reduce their noise output. The possible values are
           between 0 and 254. 128 is the most quiet (and therefore slowest) setting and 254 the
           fastest (and loudest). Some drives have only two levels (quiet / fast), while others may
           have different levels between 128 and 254. At the moment, most drives only support 3
           options, off, quiet, and fast. These have been assigned the values 0, 128, and 254 at
           present, respectively, but integer space has been incorporated for future expansion,
           should this change. This is similar to the -M option in hdparm(8).

       WriteCacheEnabled
           A boolean specifying whether to enable or disable the Write Cache. Valid values for this
           key are “true” and “false”. This is similar to the -W option in hdparm(8). This key was
           added in 2.1.

       ReadLookaheadEnabled
           A boolean specifying whether to enable or disable the Read Look-ahead. Valid values for
           this key are “true” and “false”. This is similar to the -A option in hdparm(8). This key
           was added in 2.6.0.

DEVICE INFORMATION
       udisks relies on recent versions of udev(7) and the Linux kernel. Influential device
       properties in the udev database include:

       UDISKS_SYSTEM
           If set, this overrides the value of the HintSystem property.

       UDISKS_IGNORE
           If set, this overrides the value of the HintIgnore property.

       UDISKS_AUTO
           If set, this overrides the value of the HintAuto property.

       UDISKS_CAN_POWER_OFF
           If set, this overrides the value of the CanPowerOff property.

       UDISKS_NAME
           The name to use for the device when presenting it in an user interface. This corresponds
           to the HintName property.

       UDISKS_ICON_NAME
           The icon to use for the device when presenting it in an user interface. If set, the name
           must adhere to the freedesktop.org icon theme specification[4]. This corresponds to the
           HintIconName property.

       UDISKS_SYMBOLIC_ICON_NAME
           The icon to use for the device when presenting it in an user interface using a symbolic
           icon. If set, the name must adhere to the freedesktop.org icon theme specification[4].
           This corresponds to the HintSymbolicIconName property.

       UDISKS_FILESYSTEM_SHARED
           If set to 1, the filesystem on the device will be mounted in a shared directory (e.g.
           /media/VolumeName) instead of a private directory (e.g.  /run/media/$USER/VolumeName)
           when the Filesystem.Mount() method is handled.

       ID_SEAT
           The physical seat the device is attached to. If unset or set to the empty string, “seat0”
           (the first seat) is assumed.

API STABILITY
       udisks guarantees a stable D-Bus API within the same major version and this guarantee also
       extends to the client-side library libudisks2. Additionally, several major versions of udisks
       can be installed and operate at the same time although interoperability may be limited - for
       example, a device mounted using the udisks N.x API may require additional authorization if
       attempting to unmount it through the the (N-1).x API.

       The udisks developers do not anticipate breaking API but does reserve the right to do so and
       if it happens, promises to bump the major version and ensure the new major version of udisks
       is parallel-installable with any older major version. However, note that programs, man pages
       and other artifacts may change name (for example, adopt a “2” suffix) to make room for the
       next major version. Therefore, applications can not rely on tools like e.g.  udisksctl(1) to
       be available. Additionally, there is no guarantee that the options, command-line switches
       etc. of command-line tools or similar will remain stable.

       Instead, applications should only use the D-Bus API, the libudisks2 library or tools such as
       dbus-send(1) or gdbus(1) to interact with udisksd(8).

AUDIENCE
       The intended audience of udisks include operating system developers working on the
       higher-level parts of the operating system, for example the desktop shell (such as GNOME[5])
       and disk management applications (e.g. GNOME's Disks[6] application). Software on this level
       typically depend on a specific (major) version of udisks and may even have support for
       previous versions of udisks or alternative interfaces performing the same role as udisks.

       While udisks indeed provides a stable API and a clear upgrade path, it may not be an
       appropriate dependency for third party applications. For example, if the operating system
       switches to udisks version N.x and an application is still using the udisks (N-1).x API, the
       application will not work unless udisks (N-1).x is installed. While this situation is still
       workable (since both udisks N.x and udisks (N-1).x can be installed) it may not be desirable
       to ask the user to install the old version - in fact, the operating system vendor may not
       even provide a packaged version of the old version. Hence, if an application does not want to
       tie itself to a specific version of the operating system, it should not use udisks.

       Viable alternatives to udisks are APIs that are guaranteed to be around for longer
       time-frames, including:

       •   Low-level APIs and commands such as e.g.  sysfs[7], libudev[8], /proc/self/mountinfo[9]
           and util-linux[10].

       •   High-level APIs such as GVolumeMonitor[11].

       In particular, for desktop applications it is a much better idea to use something like
       GVolumeMonitor since it will make the application show the same devices as the desktop shell
       (e.g. file manager, file chooser and so on) is showing.

AUTHOR
       This man page was originally written for UDisks2 by David Zeuthen <zeuthen AT gmail.com> with a
       lot of help from many others.

BUGS
       Please send bug reports to either the distribution bug tracker or the upstream bug tracker at
       https://github.com/storaged-project/udisks/issues.

SEE ALSO
       udev(7), polkit(8), udisksd(8), udisksctl(1), umount.udisks2(8), gnome-disks(1)

NOTES
        1. system message bus
           http://www.freedesktop.org/wiki/Software/dbus

        2. GObjectIntrospection
           https://live.gnome.org/GObjectIntrospection

        3. Desktop Entry Specification
           http://freedesktop.org/wiki/Specifications/desktop-entry-spec

        4. freedesktop.org icon theme specification
           http://www.freedesktop.org/wiki/Specifications/icon-theme-spec

        5. GNOME
           http://www.gnome.org

        6. Disks
           https://live.gnome.org/Design/Apps/Disks

        7. sysfs
           http://en.wikipedia.org/wiki/Sysfs

        8. libudev
           https://www.freedesktop.org/software/systemd/man/libudev.html

        9. /proc/self/mountinfo
           http://www.kernel.org/doc/Documentation/filesystems/proc.txt

       10. util-linux
           http://en.wikipedia.org/wiki/Util-linux

       11. GVolumeMonitor
           http://developer.gnome.org/gio/stable/volume_mon.html



udisks 2.9.4                                 August 2018                                   UDISKS(8)