Struct LoopDevice

pub struct LoopDevice { /* private fields */ }

Interface to a loop device ie /dev/loop0.

Implementations

impl LoopDevice

pub fn open<P: AsRef<Path>>(dev: P) -> Result<Self>

Opens a loop device.

Errors

This function will return an error for various reasons when opening the given loop device file. See OpenOptions::open for further details.

pub fn with(&self) -> AttachOptions<'_>

Attach the loop device to a file with given options.

Examples

Attach the device to a file.

use loopdev::LoopDevice;
let mut ld = LoopDevice::open("/dev/loop0").unwrap();
ld.with().part_scan(true).attach("disk.img").unwrap();

pub fn attach_file<P: AsRef<Path>>(&self, backing_file: P) -> Result<()>

Attach the loop device to a file that maps to the whole file.

Examples

Attach the device to a file.

use loopdev::LoopDevice;
let ld = LoopDevice::open("/dev/loop0").unwrap();
ld.attach_file("disk.img").unwrap();

Errors

This function will return an error for various reasons. Either when opening the backing file (see OpenOptions::open for further details) or when calling the ioctl to attach the backing file to the device.

pub fn path(&self) -> Option<PathBuf>

Get the path of the loop device.

pub fn major(&self) -> Result<u32>

Get the device major number

Errors

This function needs to stat the backing file and can fail if there is an IO error.

pub fn minor(&self) -> Result<u32>

Get the device major number

Errors

This function needs to stat the backing file and can fail if there is an IO error.

pub fn detach(&self) -> Result<()>

Detach a loop device from its backing file.

Note that the device won’t fully detach until a short delay after the underling device file gets closed. This happens when LoopDev goes out of scope so you should ensure the LoopDev lives for a short a time as possible.

Examples

use loopdev::LoopDevice;
let ld = LoopDevice::open("/dev/loop0").unwrap();
ld.detach().unwrap();

Errors

This function will return an error for various reasons when calling the ioctl to detach the backing file from the device.

pub fn set_capacity(&self) -> Result<()>

Resize a live loop device. If the size of the backing file changes this can be called to inform the loop driver about the new size.

Errors

This function will return an error for various reasons when calling the ioctl to set the capacity of the device.

Trait Implementations

impl AsRawFd for LoopDevice

fn as_raw_fd(&self) -> RawFd

Extracts the raw file descriptor.

impl Debug for LoopDevice

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl IntoRawFd for LoopDevice

fn into_raw_fd(self) -> RawFd

Consumes this object, returning the raw underlying file descriptor.