bjorn3
f1057b6750
All users did this anyway. And handling it inside the daemon crate allows avoiding a panic of the parent process when the child process panicked.
47 lines
1.1 KiB
Rust
47 lines
1.1 KiB
Rust
#![feature(never_type)]
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use std::io::{self, PipeWriter, Read, Write};
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#[must_use = "Daemon::ready must be called"]
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pub struct Daemon {
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write_pipe: PipeWriter,
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}
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fn errno() -> io::Error {
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io::Error::last_os_error()
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}
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impl Daemon {
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pub fn new<F: FnOnce(Daemon) -> !>(f: F) -> ! {
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let (mut read_pipe, write_pipe) = std::io::pipe().unwrap();
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match unsafe { libc::fork() } {
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0 => {
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drop(read_pipe);
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f(Daemon { write_pipe })
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}
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-1 => return Err(errno()).unwrap(),
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_pid => {
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drop(write_pipe);
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let mut data = [0];
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match read_pipe.read_exact(&mut data) {
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Ok(()) => {}
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Err(err) if err.kind() == io::ErrorKind::UnexpectedEof => {
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unsafe { libc::_exit(101) };
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}
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Err(err) => return Err(err).unwrap(),
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};
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unsafe { libc::_exit(data[0].into()) };
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}
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}
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}
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pub fn ready(mut self) {
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self.write_pipe.write_all(&[0]).unwrap();
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}
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}
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