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reexec: double-fork to prevent the creation of zombies

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Julian Orth 2025-04-25 20:08:02 +02:00
parent 8552c5f1eb
commit fcf4cef6de
1 changed files with 30 additions and 21 deletions
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51
src/ifs/jay_reexec.rs
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@ -12,7 +12,7 @@ use {
}, },
std::{array::from_mut, cell::RefCell, rc::Rc}, std::{array::from_mut, cell::RefCell, rc::Rc},
thiserror::Error, thiserror::Error,
uapi::{OwnedFd, UstrPtr, c, close_range, dup2, pipe2}, uapi::{OwnedFd, UstrPtr, c, close_range, dup2, pipe2, waitpid},
}; };
pub struct JayReexec { pub struct JayReexec {
@ -51,27 +51,36 @@ impl JayReexec {
let (p1, c1) = pipe!(); let (p1, c1) = pipe!();
let (c2, p2) = pipe!(); let (c2, p2) = pipe!();
if let Ok(f) = fork_with_pidfd(false) { if let Ok(f) = fork_with_pidfd(false) {
if let Forked::Child { .. } = f { match f {
drop(p2); Forked::Parent { pid, .. } => {
fds.sort_by_key(|fd| fd.raw()); let _ = waitpid(pid, 0);
let c2_dup = fds.last().unwrap().raw() + 1;
let c1_dup = c2_dup + 1;
let _ = dup2(c1.raw(), c1_dup);
let _ = dup2(c2.raw(), c2_dup);
for (idx, fd) in fds.iter().enumerate() {
let _ = dup2(fd.raw(), idx as _);
} }
let c2_dup_dup = fds.len() as _; Forked::Child { .. } => {
let _ = dup2(c2_dup, c2_dup_dup); if let Ok(f) = fork_with_pidfd(false) {
let _ = close_range(c2_dup_dup as c::c_uint + 1, !0, 0); if let Forked::Child { .. } = f {
let mut pollfd = c::pollfd { drop(p2);
fd: c2_dup_dup, fds.sort_by_key(|fd| fd.raw());
events: 0, let c2_dup = fds.last().unwrap().raw() + 1;
revents: 0, let c1_dup = c2_dup + 1;
}; let _ = dup2(c1.raw(), c1_dup);
let _ = uapi::poll(from_mut(&mut pollfd), -1); let _ = dup2(c2.raw(), c2_dup);
unsafe { for (idx, fd) in fds.iter().enumerate() {
c::_exit(0); let _ = dup2(fd.raw(), idx as _);
}
let c2_dup_dup = fds.len() as _;
let _ = dup2(c2_dup, c2_dup_dup);
let _ = close_range(c2_dup_dup as c::c_uint + 1, !0, 0);
let mut pollfd = c::pollfd {
fd: c2_dup_dup,
events: 0,
revents: 0,
};
let _ = uapi::poll(from_mut(&mut pollfd), -1);
}
}
unsafe {
c::_exit(0);
}
} }
} }
} }