Struct Process 

pub struct Process { /* private fields */ }

A handle to a spawned process.

Fork Safety

The process handle contains a PID. After a fork, the child process will have a copy of this PID, but it refers to the same original process. Calling wait or kill from the child may lead to confusing results if multiple processes are managing the same PID.

When the process was spawned by SpawnBackend::Clone3Pidfd, the handle additionally owns the child’s pidfd. Signaling then uses pidfd_send_signal, which cannot race with pid reuse, and exit detection polls the pidfd. The pidfd is closed when the handle is dropped.

Implementations

impl Process

pub fn new(pid: pid_t) -> Self

Create a handle for an existing PID (no pidfd).

pub fn pid(&self) -> pid_t

Return the process ID.

pub fn pidfd(&self) -> Option<RawFd>

Return the pidfd owned by this handle, if any.

pub fn wait_step(&self) -> Result<Option<ExitStatus>, CoreError>

Perform a non-blocking wait for process termination.

When the handle owns a pidfd, the wait first polls the pidfd (which becomes readable exactly when the child exits) and then reaps with waitpid, avoiding the ECHILD-race of polling waitpid directly.

Errors

• ECHILD: The process does not exist or is not a child of the caller.
• EINTR: The call was interrupted by a signal (handled internally).

pub fn wait_blocking(&self) -> Result<ExitStatus, CoreError>

Block until the process terminates.

Errors

• ECHILD: The process does not exist or is not a child of the caller.

pub fn kill(&self, sig: i32) -> Result<(), CoreError>

Send a signal to the process.

When the handle owns a pidfd, the signal is delivered with pidfd_send_signal, which cannot target a recycled pid; on kernels without it (ENOSYS, kernel < 5.1) it falls back to kill.

Errors

• EINVAL: Invalid signal number, or a non-positive pid (pid 0 would signal the caller’s own process group).
• EPERM: The caller does not have permission to send the signal.
• ESRCH: The process does not exist.

pub fn kill_pgroup(&self, sig: i32) -> Result<(), CoreError>

Signal the process group whose id equals Self::pid — valid only when the process is its own group/session leader. For a child placed into a custom leader’s group use Self::kill_group.

Errors

Same as Self::kill.

pub fn kill_group(&self, pgid: pid_t, sig: i32) -> Result<(), CoreError>

Send a signal to an explicit process group.

The pgid must be the child’s actual group (its own pid after setsid, or the configured leader’s id after setpgid), never guessed from the pid, and never 0 or negative — kill(-0) would signal the caller’s own process group.

Errors

Same as Self::kill, plus EINVAL for a non-positive pgid.

Trait Implementations

impl Drop for Process

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.