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#[cfg(unix)]
pub(crate) fn acquire_terminal(interactive: bool) {
use is_terminal::IsTerminal;
use nix::{
errno::Errno,
sys::signal::{signal, SigHandler, Signal},
unistd,
};
if interactive && std::io::stdin().is_terminal() {
// see also: https://www.gnu.org/software/libc/manual/html_node/Initializing-the-Shell.html
take_control();
unsafe {
// SIGINT and SIGQUIT have special handling above
signal(Signal::SIGTSTP, SigHandler::SigIgn).expect("signal ignore");
signal(Signal::SIGTTIN, SigHandler::SigIgn).expect("signal ignore");
signal(Signal::SIGTTOU, SigHandler::SigIgn).expect("signal ignore");
}
// Put ourselves in our own process group, if not already
let shell_pgid = unistd::getpid();
match unistd::setpgid(shell_pgid, shell_pgid) {
// setpgid returns EPERM if we are the session leader (e.g., as a login shell).
// The other cases that return EPERM cannot happen, since we gave our own pid.
// See: setpgid(2)
// Therefore, it is safe to ignore EPERM.
Ok(()) | Err(Errno::EPERM) => (),
Err(_) => {
eprintln!("ERROR: failed to put nushell in its own process group");
std::process::exit(1);
}
}
// Set our possibly new pgid to be in control of terminal
let _ = unistd::tcsetpgrp(nix::libc::STDIN_FILENO, shell_pgid);
}
}
#[cfg(not(unix))]
pub(crate) fn acquire_terminal(_: bool) {}
// Inspired by fish's acquire_tty_or_exit
#[cfg(unix)]
fn take_control() {
use nix::{
errno::Errno,
sys::signal::{self, SaFlags, SigAction, SigHandler, SigSet, Signal},
unistd::{self, Pid},
};
let shell_pgid = unistd::getpgrp();
match unistd::tcgetpgrp(nix::libc::STDIN_FILENO) {
Ok(owner_pgid) if owner_pgid == shell_pgid => {
// Common case, nothing to do
return;
}
Ok(owner_pgid) if owner_pgid == unistd::getpid() => {
// This can apparently happen with sudo: https://github.com/fish-shell/fish-shell/issues/7388
let _ = unistd::setpgid(owner_pgid, owner_pgid);
return;
}
_ => (),
}
// Reset all signal handlers to default
for sig in Signal::iterator() {
unsafe {
if let Ok(old_act) = signal::sigaction(
sig,
&SigAction::new(SigHandler::SigDfl, SaFlags::empty(), SigSet::empty()),
) {
// fish preserves ignored SIGHUP, presumably for nohup support, so let's do the same
if sig == Signal::SIGHUP && old_act.handler() == SigHandler::SigIgn {
let _ = signal::sigaction(sig, &old_act);
}
}
}
}
for _ in 0..4096 {
match unistd::tcgetpgrp(nix::libc::STDIN_FILENO) {
Ok(owner_pgid) if owner_pgid == shell_pgid => {
// success
return;
}
Ok(owner_pgid) if owner_pgid == Pid::from_raw(0) => {
// Zero basically means something like "not owned" and we can just take it
let _ = unistd::tcsetpgrp(nix::libc::STDIN_FILENO, shell_pgid);
}
Err(Errno::ENOTTY) => {
eprintln!("ERROR: no TTY for interactive shell");
std::process::exit(1);
}
_ => {
// fish also has other heuristics than "too many attempts" for the orphan check, but they're optional
if signal::killpg(shell_pgid, Signal::SIGTTIN).is_err() {
eprintln!("ERROR: failed to SIGTTIN ourselves");
std::process::exit(1);
}
}
}
}
eprintln!("ERROR: failed take control of the terminal, we might be orphaned");
std::process::exit(1);
}