Module process_group 

Process-group helpers for reliable child process cleanup.

This module centralizes OS-specific pieces that ensure a spawned command can be cleaned up reliably:

• set_process_group is called in pre_exec so the child starts its own process group.
• detach_from_tty starts a new session so non-interactive children do not inherit the controlling TTY.
• kill_process_group_by_pid targets the whole group (children/grandchildren) instead of a single PID.
• kill_process_group targets a known process group ID directly.
• set_parent_death_signal (Linux only) arranges for the child to receive a SIGTERM when the parent exits, and re-checks the parent PID to avoid races during fork/exec.
• graceful_kill_process_group sends SIGTERM, waits for a grace period, then SIGKILL if still running.

On non-Unix platforms these helpers are no-ops or adapted equivalents.

Inspired by codex-rs/utils/pty process group management patterns.

Enums

GracefulTerminationResult

Result of a graceful termination attempt.

KillSignal

Signal to send when killing process groups.

Constants

DEFAULT_GRACEFUL_TIMEOUT_MS

Default grace period for graceful termination (milliseconds).

Functions

detach_from_tty

No-op on non-Unix platforms.

graceful_kill_process_group

Graceful termination on non-Unix (best effort).

graceful_kill_process_group_default

Graceful termination with defaults on non-Unix.

kill_child_process_group

No-op on non-Unix platforms.

kill_child_process_group_with_signal

No-op on non-Unix platforms.

kill_process

Kill a process by PID on Windows.

kill_process_group

No-op on non-Unix platforms.

kill_process_group_by_pid

No-op on non-Unix platforms.

kill_process_group_by_pid_with_signal

No-op on non-Unix platforms.

kill_process_group_with_signal

No-op on non-Unix platforms.

set_parent_death_signal

No-op on non-Linux platforms.

set_process_group

No-op on non-Unix platforms.