Struct vmm_vhost::sys::unix::SocketPlatformConnection

pub struct SocketPlatformConnection {
    sock: ScmSocket<UnixStream>,
}

Unix domain socket based vhost-user connection.

Fields

sock: ScmSocket<UnixStream>

Implementations

impl SocketPlatformConnection

fn send_iovec_all( &self, iovs: &mut [&[u8]], fds: Option<&[RawDescriptor]> ) -> Result<()>

Sends all bytes from scatter-gather vectors with optional attached file descriptors. Will loop until all data has been transfered.

TODO

This function takes a slice of &[u8] instead of IoSlice because the internal cursor needs to be moved by advance_slices(). Once IoSlice::advance_slices() becomes stable, this should be updated. https://github.com/rust-lang/rust/issues/62726.

pub fn send_message( &self, hdr: &[u8], body: &[u8], payload: &[u8], fds: Option<&[RawDescriptor]> ) -> Result<()>

Sends a single message over the socket with optional attached file descriptors.

• hdr: vhost message header
• body: vhost message body (may be empty to send a header-only message)
• payload: additional bytes to append to body (may be empty)

pub fn recv_into_bufs( &self, bufs: &mut [IoSliceMut<'_>], allow_fd: bool ) -> Result<(usize, Option<Vec<File>>)>

Reads bytes from the socket into the given scatter/gather vectors with optional attached file.

The underlying communication channel is a Unix domain socket in STREAM mode. It’s a little tricky to pass file descriptors through such a communication channel. Let’s assume that a sender sending a message with some file descriptors attached. To successfully receive those attached file descriptors, the receiver must obey following rules:

1. file descriptors are attached to a message.
2. message(packet) boundaries must be respected on the receive side.

In other words, recvmsg() operations must not cross the packet boundary, otherwise the attached file descriptors will get lost. Note that this function wraps received file descriptors as File.

Return:

• • (number of bytes received, [received files]) on success
• • Disconnect: the connection is closed.
• • SocketRetry: temporary error caused by signals or short of resources.
• • SocketBroken: the underline socket is broken.
• • SocketError: other socket related errors.

Trait Implementations

impl AsRawDescriptor for SocketPlatformConnection

fn as_raw_descriptor(&self) -> RawDescriptor

Returns the underlying raw descriptor.

impl ReadNotifier for SocketPlatformConnection

fn get_read_notifier(&self) -> &dyn AsRawDescriptor

Gets a descriptor that can be used in EventContext to wait for events to be available (e.g. to avoid receive_events blocking).