77 lines
2.2 KiB
Rust
77 lines
2.2 KiB
Rust
// Copyright 2023 System76 <info@system76.com>
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// SPDX-License-Identifier: MPL-2.0
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#[cfg(all(feature = "smol", not(feature = "tokio")))]
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use smol::io::AsyncReadExt;
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use std::io;
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use std::os::fd::OwnedFd;
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use std::process::{exit, Command, Stdio};
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#[cfg(feature = "tokio")]
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use tokio::io::AsyncReadExt;
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#[cfg(feature = "tokio")]
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async fn read_from_pipe(read: OwnedFd) -> Option<u32> {
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let mut read = tokio::net::unix::pipe::Receiver::from_owned_fd(read).unwrap();
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read.read_u32().await.ok()
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}
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#[cfg(all(feature = "smol", not(feature = "tokio")))]
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async fn read_from_pipe(read: OwnedFd) -> Option<u32> {
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let mut read = smol::Async::new(std::fs::File::from(read)).unwrap();
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let mut bytes = [0; 4];
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read.read_exact(&mut bytes).await.ok()?;
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Some(u32::from_be_bytes(bytes))
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}
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/// Performs a double fork with setsid to spawn and detach a command.
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pub async fn spawn(mut command: Command) -> Option<u32> {
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// NOTE: Windows platform is not supported
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command
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.stdin(Stdio::null())
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.stdout(Stdio::null())
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.stderr(Stdio::null());
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// Handle Linux
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#[cfg(all(unix, not(target_os = "macos")))]
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let Ok((read, write)) = rustix::pipe::pipe_with(rustix::pipe::PipeFlags::CLOEXEC) else {
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return None;
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};
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// Handle macOS
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#[cfg(target_os = "macos")]
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let Ok((read, write)) = rustix::pipe::pipe() else {
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return None;
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};
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match unsafe { libc::fork() } {
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// Parent process
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1.. => {
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// Drop copy of write end, then read PID from pipe
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drop(write);
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let pid = read_from_pipe(read).await;
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// wait to prevent zombie
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_ = rustix::process::wait(rustix::process::WaitOptions::empty());
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pid
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}
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// Child process
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0 => {
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let _res = rustix::process::setsid();
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if let Ok(child) = command.spawn() {
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// Write PID to pipe
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let _ = rustix::io::write(write, &child.id().to_be_bytes());
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}
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exit(0)
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}
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..=-1 => {
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println!(
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"failed to fork and spawn command: {}",
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io::Error::last_os_error()
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);
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None
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}
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}
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}
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