io.systemd.MountFileSystem¶

APIs for unprivileged mounting.

Property	Value
Go package	`github.com/rossedman/sdvarlink/systemd/latest/mountfilesystem`
Socket	`/run/systemd/io.systemd.MountFileSystem`
Available since	systemd v257
Methods · types · errors	3 · 3 · 7

Methods¶

MountImage¶

passes file descriptors

Takes a disk image file descriptor as input, returns a set of mount file descriptors for it, plus meta information about the image and the partitions selected for mounting.

func (c *Client) MountImage(ctx context.Context, in MountImageIn) (*MountImageOut, error)

Parameters

Field	Type	Description
`imageFileDescriptor`	`int`	File descriptor of the image file to mount and to assign to the user namespace. Must be a regular, i.e. non-O_PATH file descriptor.
`userNamespaceFileDescriptor`	`?int`	File descriptor to the user namespace to assign this image to. If not specified uses the host user namespace.
`readOnly`	`?bool`	Mounts the image read-only.
`growFileSystems`	`?bool`	Grows the contained file systems if necessary and indicated, before mounting them.
`password`	`?string`	Takes a literal password in case of an encrypted image
`imagePolicy`	`?string`	Takes an image policy string (see systemd.image-policy(7) for details) to apply while mounting the image
`mountOptions`	`?[string]string`	The mount options to be used for the partitions of the image, keyed by the partition designator. Requires elevated privileges via polkit if specified, the polkit request details will list them in the 'mount_options' field.
`relaxExtensionReleaseChecks`	`?bool`	Whether to relax the extension release checks when mounting the image.
`veritySharing`	`?bool`	Whether to automatically reuse already set up dm-verity devices that share the same roothash.
`verityDataFileDescriptor`	`?int`	File descriptor of the file containing the dm-verity data, if the image is a bare filesystem rather than a DDI.
`verityRootHash`	`?string`	The expected dm-verity root hash as an hex encoded string, if the image is a bare filesystem rather than a DDI.
`verityRootHashSignature`	`?string`	The expected signature for the dm-verity root hash as a Base64 encoded string, if the image is a bare filesystem rather than a DDI.
`allowInteractiveAuthentication`	`?bool`	Controls whether interactive authentication (via polkit) shall be allowed. If unspecified defaults to false.

Reply

Field	Type	Description
`partitions`	`[]PartitionInfo`	An array with information about contained partitions that have been prepared for mounting, as well as their mount file descriptors.
`singleFileSystem`	`bool`	Indicates whether the image contains only a single file system, i.e. no partition table.
`imagePolicy`	`string`	The used image policy.
`imageSize`	`int`	The size of the image in bytes.
`sectorSize`	`int`	The sector size of the image in bytes
`imageName`	`?string`	The name of the image
`imageUuid`	`?string`	The UUID of the image

MountDirectory¶

since v258 · passes file descriptors

Takes a directory file descriptor as input, returns a mount file descriptor.

func (c *Client) MountDirectory(ctx context.Context, in MountDirectoryIn) (*MountDirectoryOut, error)

Parameters

Field	Type	Description
`directoryFileDescriptor`	`int`	Directory file descriptor of the directory to assign to the user namespace. Must be a regular, i.e. non-O_PATH file descriptor.
`userNamespaceFileDescriptor`	`?int`	File descriptor to the user namespace to assign this directory to. If not specified uses the host user namespace.
`readOnly`	`?bool`	Whether to mark the resulting mount file descriptor as read-only. If not specified defaults to false.
`mode`	`?MountMapMode`	Which kind of UID/GID mapping to apply to the resulting mount file descriptor.
`allowInteractiveAuthentication`	`?bool`	Controls whether interactive authentication (via polkit) shall be allowed. If unspecified defaults to false.

Reply

Field	Type	Description
`mountFileDescriptor`	`int`	The freshly allocated mount file descriptor for the mount.

MakeDirectory¶

since v258 · passes file descriptors

Creates an empty directory, owned by the foreign UID/GID range's root user, returns an open file descriptor to the directory. Access mode will be set to 0700.

func (c *Client) MakeDirectory(ctx context.Context, in MakeDirectoryIn) (*MakeDirectoryOut, error)

Parameters

Field	Type	Description
`parentFileDescriptor`	`int`	File descriptor of the directory to create the new directory in. Must be a regular, i.e. non-O_PATH file descriptor.
`name`	`string`	Name of the directory to create.
`mode`	`?int`	Access mode of the directory to create. Note that the suid, sgid, sticky, world-writable bit is unconditionally masked off.
`allowInteractiveAuthentication`	`?bool`	Controls whether interactive authentication (via polkit) shall be allowed. If unspecified defaults to false.

Reply

Field	Type	Description
`directoryFileDescriptor`	`int`	File descriptor referencing the newly created directory.

Types¶

PartitionDesignator¶

Encodes the designated purpose of a partition.

Value	Description
`root`
`usr`
`home`
`srv`
`esp`
`xbootldr`
`swap`
`root_verity`
`usr_verity`
`root_verity_sig`
`usr_verity_sig`
`tmp`
`var`

MountMapMode¶

Selects the type of UID/GID mapping to apply.

Value	Description
`root`	Map the caller's UID to root in the user namespace, do not map anything else.
`foreign`	Map the foreign UID range to the base UID range in the user namespace (i.e. UID zero and above), covering 64K users.
`identity`	Apply an identity (1:1) mapping, but limit it to 64K users.
`auto`	Determine automatically based on provided directory and caller.

PartitionInfo¶

Information about a specific partition.

Field	Type	Description
`designator`	`PartitionDesignator`	The designator of this partition.
`writable`	`bool`	Indicates whether this partition is marked for writable (non-read-only) operations.
`growFileSystem`	`bool`	Indicates whether this partition is marked for automatic growing.
`partitionNumber`	`?int`	Indicates the numeric partition number of this partition, or null if the image does not carry a partition table, and this object covers the whole block device.
`architecture`	`?string`	Indicates the intended CPU architecture of the partition, in case the partition type encodes such information.
`partitionUuid`	`?string`	The partition UUID identifying the partition.
`fileSystemType`	`string`	The file system type for the mount
`partitionLabel`	`?string`	The partition label string of this partition.
`size`	`int`	The size of the partition in bytes.
`offset`	`int`	The start offset of the partition in bytes.
`mountFileDescriptor`	`int`	A mount file descriptor to assign to a location.
`mountPoint`	`?[]string`	A relative path indicating the intended mount point for this file system, if applicable. May contain multiple paths, for certain partitions that can be mounted to multiple distinct places.

Errors¶

Error	Go type	Description
`IncompatibleImage`	`IncompatibleImageError`	Disk image is not compatible with this service.
`MultipleRootPartitionsFound`	`MultipleRootPartitionsFoundError`	Multiple suitable root partitions found.
`RootPartitionNotFound`	`RootPartitionNotFoundError`	No suitable root partition found.
`DeniedByImagePolicy`	`DeniedByImagePolicyError`	The specified image policy disallows mounting this disk image
`KeyNotFound`	`KeyNotFoundError`	The authentication key for this image is not available.
`VerityFailure`	`VerityFailureError`	Verity could not be set up.
`BadFileDescriptorFlags`	`BadFileDescriptorFlagsError`	A passed file descriptor has unexpected/forbidden flags set.