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Merge pull request #445 from mahkoh/jorth/reexec-double-fork

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reexec: double-fork to prevent the creation of zombies
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mahkoh 2025-04-25 20:10:28 +02:00 • committed by GitHub
commit 7eb47a42c2
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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},
thiserror::Error,
uapi::{OwnedFd, UstrPtr, c, close_range, dup2, pipe2},
uapi::{OwnedFd, UstrPtr, c, close_range, dup2, pipe2, waitpid},
};
pub struct JayReexec {
@ -51,27 +51,36 @@ impl JayReexec {
let (p1, c1) = pipe!();
let (c2, p2) = pipe!();
if let Ok(f) = fork_with_pidfd(false) {
if let Forked::Child { .. } = f {
drop(p2);
fds.sort_by_key(|fd| fd.raw());
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 _);
match f {
Forked::Parent { pid, .. } => {
let _ = waitpid(pid, 0);
}
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);
Forked::Child { .. } => {
if let Ok(f) = fork_with_pidfd(false) {
if let Forked::Child { .. } = f {
drop(p2);
fds.sort_by_key(|fd| fd.raw());
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 _;
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);
}
}
}
}