Struct CmdFds 

pub struct CmdFds { /* private fields */ }

File descriptor allocator for child processes.

Collects fd assignments and optional systemd socket-activation configuration, then applies them all at once via CapStdExtCommandExt::take_fds.

• new_systemd_fds creates an allocator with systemd socket-activation fds at 3, 4, … (SD_LISTEN_FDS_START).
• take_fd auto-assigns the next fd above all previously assigned ones (minimum 3).
• take_fd_n places an fd at an explicit number, panicking on overlap.

let mut cmd = std::process::Command::new("myservice");
let mut fds = CmdFds::new_systemd_fds([(varlink_fd, SystemdFdName::new("varlink"))]);
let extra_n = fds.take_fd(extra_fd);
cmd.take_fds(fds);

Implementations

impl CmdFds

pub fn new() -> Self

Create a new fd allocator.

pub fn new_systemd_fds<'a>( fds: impl IntoIterator<Item = (Arc<OwnedFd>, SystemdFdName<'a>)>, ) -> Self

Create a new fd allocator with systemd socket-activation fds.

Each (fd, name) pair is assigned a consecutive fd number starting at SD_LISTEN_FDS_START (3). The LISTEN_PID, LISTEN_FDS, and LISTEN_FDNAMES environment variables will be set in the child when CapStdExtCommandExt::take_fds is called.

Additional (non-systemd) fds can be registered afterwards via take_fd or take_fd_n.

pub fn take_fd(&mut self, fd: Arc<OwnedFd>) -> i32

Register a file descriptor at the next available fd number.

Returns the fd number that will be assigned in the child. Call CapStdExtCommandExt::take_fds to apply.

pub fn take_fd_n(&mut self, fd: Arc<OwnedFd>, target: i32) -> &mut Self

Register a file descriptor at a specific fd number.

Call CapStdExtCommandExt::take_fds to apply.

Panics

Panics if target has already been assigned.

Trait Implementations

impl Debug for CmdFds

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

Formats the value using the given formatter.

impl Default for CmdFds

fn default() -> Self

Returns the “default value” for a type.