Struct UserSliceReader

pub struct UserSliceReader { /* private fields */ }

A reader for UserSlice.

Used to incrementally read from the user slice.

Implementations

impl UserSliceReader

pub fn skip(&mut self, num_skip: usize) -> Result

Skip the provided number of bytes.

Returns an error if skipping more than the length of the buffer.

pub fn clone_reader(&self) -> UserSliceReader

Create a reader that can access the same range of data.

Reading from the clone does not advance the current reader.

The caller should take care to not introduce TOCTOU issues, as described in the documentation for UserSlice.

pub fn len(&self) -> usize

Returns the number of bytes left to be read from this reader.

Note that even reading less than this number of bytes may fail.

pub fn is_empty(&self) -> bool

Returns true if no data is available in the io buffer.

pub fn read_raw(&mut self, out: &mut [MaybeUninit<u8>]) -> Result

Reads raw data from the user slice into a kernel buffer.

For a version that uses &mut [u8], please see UserSliceReader::read_slice.

Fails with EFAULT if the read happens on a bad address, or if the read goes out of bounds of this UserSliceReader. This call may modify out even if it returns an error.

Guarantees

After a successful call to this method, all bytes in out are initialized.

pub fn read_slice(&mut self, out: &mut [u8]) -> Result

Reads raw data from the user slice into a kernel buffer.

Fails with EFAULT if the read happens on a bad address, or if the read goes out of bounds of this UserSliceReader. This call may modify out even if it returns an error.

pub fn read<T: FromBytes>(&mut self) -> Result<T>

Reads a value of the specified type.

Fails with EFAULT if the read happens on a bad address, or if the read goes out of bounds of this UserSliceReader.

pub fn read_all<A: Allocator>( self, buf: &mut Vec<u8, A>, flags: Flags, ) -> Result

Reads the entirety of the user slice, appending it to the end of the provided buffer.

Fails with EFAULT if the read happens on a bad address.

pub fn strcpy_into_buf<'buf>(self, buf: &'buf mut [u8]) -> Result<&'buf CStr>

Read a NUL-terminated string from userspace and return it.

The string is read into buf and a NUL-terminator is added if the end of buf is reached. Since there must be space to add a NUL-terminator, the buffer must not be empty. The returned &CStr points into buf.

Fails with EFAULT if the read happens on a bad address (some data may have been copied).