Struct IoVecBuffer 

pub struct IoVecBuffer { /* private fields */ }

This is essentially a wrapper of a Vec<libc::iovec> which can be passed to libc::writev.

It describes a buffer passed to us by the guest that is scattered across multiple memory regions. Additionally, this wrapper provides methods that allow reading arbitrary ranges of data from that buffer.

Implementations

impl IoVecBuffer

pub unsafe fn load_descriptor_chain( &mut self, mem: &GuestMemoryMmap, head: DescriptorChain, ) -> Result<(), IoVecError>

Create an IoVecBuffer from a DescriptorChain

Safety

The descriptor chain cannot be referencing the same memory location as another chain

pub unsafe fn from_descriptor_chain( mem: &GuestMemoryMmap, head: DescriptorChain, ) -> Result<Self, IoVecError>

Create an IoVecBuffer from a DescriptorChain

Safety

The descriptor chain cannot be referencing the same memory location as another chain

pub fn as_iovec_ptr(&self) -> *const iovec

Returns a pointer to the memory keeping the iovec structs

pub fn iovec_count(&self) -> usize

Returns the length of the iovec array.

pub fn clear(&mut self)

Clears the iovec array

pub fn read_exact_volatile_at( &self, buf: &mut [u8], offset: usize, ) -> Result<(), VolatileMemoryError>

Reads a number of bytes from the IoVecBuffer starting at a given offset.

This will try to fill buf reading bytes from the IoVecBuffer starting from the given offset.

Returns

Ok(()) if buf was filled by reading from this IoVecBuffer, Err(VolatileMemoryError::PartialBuffer) if only part of buf could not be filled, and Err(VolatileMemoryError::OutOfBounds) if offset >= self.len().

pub fn read_volatile_at<W: WriteVolatile>( &self, dst: &mut W, offset: usize, len: usize, ) -> Result<usize, VolatileMemoryError>

Reads up to len bytes from the IoVecBuffer starting at the given offset.

This will try to write to the given [WriteVolatile].

Trait Implementations

impl Debug for IoVecBuffer

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

Formats the value using the given formatter.

impl Default for IoVecBuffer

fn default() -> IoVecBuffer

Returns the “default value” for a type.

impl Send for IoVecBuffer