Struct SupervisorSocket 

pub struct SupervisorSocket { /* private fields */ }

A Unix domain socket for supervisor IPC.

Created by the supervisor before fork. The child inherits one end via the forked file descriptor table, or the fd is explicitly passed.

Protocol

Messages are length-prefixed JSON:

[4 bytes: u32 big-endian length][N bytes: JSON payload]

When granting access, the supervisor sends the response message AND passes an opened file descriptor via SCM_RIGHTS ancillary data.

Implementations

impl SupervisorSocket

pub fn pair() -> Result<(Self, Self)>

Create a connected socket pair for supervisor-child IPC.

Returns (supervisor_end, child_end). Call this before fork:

• The supervisor keeps supervisor_end
• The child inherits child_end (or it’s passed explicitly)

pub fn bind(path: &Path) -> Result<Self>

Create a supervisor socket bound to a filesystem path.

The supervisor binds and listens; the child connects after fork. The socket file is cleaned up on drop.

pub fn connect(path: &Path) -> Result<Self>

Connect to a supervisor socket at the given path.

pub fn from_stream(stream: UnixStream) -> Self

Wrap an existing UnixStream (e.g., from an inherited fd after fork).

pub fn as_raw_fd(&self) -> RawFd

Get the raw file descriptor for this socket.

Useful for passing to the child process via environment variable or for select()/poll() integration.

pub fn send_message(&mut self, msg: &SupervisorMessage) -> Result<()>

Send a message from child to supervisor.

pub fn recv_message(&mut self) -> Result<SupervisorMessage>

Receive a message from child (supervisor side).

pub fn send_response(&mut self, resp: &SupervisorResponse) -> Result<()>

Send a response from supervisor to child.

pub fn recv_response(&mut self) -> Result<SupervisorResponse>

Receive a response from supervisor (child side).

pub fn send_fd(&self, fd: RawFd) -> Result<()>

Send a file descriptor to the peer via SCM_RIGHTS.

Used by the supervisor to pass an opened fd for a granted path.

pub fn recv_fd(&self) -> Result<OwnedFd>

Receive a file descriptor from the peer via SCM_RIGHTS.

Used by the child to receive an opened fd for a granted path. Returns an OwnedFd that the caller is responsible for.

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

Authenticate the peer using platform-specific mechanisms.

On Linux, uses SO_PEERCRED to get the peer’s PID/UID/GID. On macOS, combines LOCAL_PEERPID and getpeereid.

Returns the peer’s PID.

pub fn set_read_timeout(&self, timeout: Option<Duration>) -> Result<()>

Set a read timeout on the socket.

Trait Implementations

impl Drop for SupervisorSocket

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.