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Use libc::pause instead of std:🧵:park in wait-for-exit loop

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This commit is contained in:
Zachary S 2024-07-03 13:02:47 -05:00
parent c36fdeb9a3
commit 5e83fafd88
1 changed files with 10 additions and 7 deletions
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17
library/std/src/sys/pal/common/exit_guard.rs
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@ -10,9 +10,9 @@ cfg_if::cfg_if! {
} else if #[cfg(target_os = "linux")] {
/// Mitigation for <https://github.com/rust-lang/rust/issues/126600>
///
/// On `unix` (where `libc::exit` may not be thread-safe), ensure that only one Rust thread
/// calls `libc::exit` (or returns from `main`) by calling this function before calling
/// `libc::exit` (or returning from `main`).
/// On UNIX-like platforms (where `libc::exit` may not be thread-safe), ensure that only one
/// Rust thread calls `libc::exit` (or returns from `main`) by calling this function before
/// calling `libc::exit` (or returning from `main`).
///
/// Technically not enough to ensure soundness, since other code directly calling
/// libc::exit will still race with this.
@ -23,7 +23,7 @@ cfg_if::cfg_if! {
/// This function will return only the first time it is called in a process.
///
/// * If it is called again on the same thread as the first call, it will abort.
/// * If it is called again on a different thread, it will `thread::park()` in a loop
/// * If it is called again on a different thread, it will wait in a loop
/// (waiting for the process to exit).
pub(crate) fn unique_thread_exit() {
let this_thread_id = unsafe { libc::gettid() };
@ -52,9 +52,10 @@ cfg_if::cfg_if! {
}
Err(_) => {
// This is not the first thread to call `unique_thread_exit`.
// Park until the process exits.
// Pause until the process exits.
loop {
crate::thread::park();
// Safety: libc::pause is safe to call.
unsafe { libc::pause(); }
}
}
}
@ -77,10 +78,12 @@ cfg_if::cfg_if! {
core::panicking::panic_nounwind("std::process::exit called re-entrantly")
} else {
// This is not the first thread to call `unique_thread_exit`.
// Pause until the process exits.
// Park until the process exits.
drop(exiting_thread_id);
loop {
crate::thread::park();
// Safety: libc::pause is safe to call.
unsafe { libc::pause(); }
}
}
}