diff options
Diffstat (limited to 'library/std/src/thread')
| -rw-r--r-- | library/std/src/thread/current.rs | 20 | ||||
| -rw-r--r-- | library/std/src/thread/mod.rs | 24 |
2 files changed, 24 insertions, 20 deletions
diff --git a/library/std/src/thread/current.rs b/library/std/src/thread/current.rs index b38149a0da7..e6eb90c4c30 100644 --- a/library/std/src/thread/current.rs +++ b/library/std/src/thread/current.rs @@ -110,22 +110,24 @@ mod id { } } -/// Sets the thread handle for the current thread. -/// -/// Aborts if the handle or the ID has been set already. -pub(crate) fn set_current(thread: Thread) { - if CURRENT.get() != NONE || id::get().is_some() { - // Using `panic` here can add ~3kB to the binary size. We have complete - // control over where this is called, so just abort if there is a bug. - rtabort!("thread::set_current should only be called once per thread"); +/// Tries to set the thread handle for the current thread. Fails if a handle was +/// already set or if the thread ID of `thread` would change an already-set ID. +pub(crate) fn set_current(thread: Thread) -> Result<(), Thread> { + if CURRENT.get() != NONE { + return Err(thread); } - id::set(thread.id()); + match id::get() { + Some(id) if id == thread.id() => {} + None => id::set(thread.id()), + _ => return Err(thread), + } // Make sure that `crate::rt::thread_cleanup` will be run, which will // call `drop_current`. crate::sys::thread_local::guard::enable(); CURRENT.set(thread.into_raw().cast_mut()); + Ok(()) } /// Gets the id of the thread that invokes it. diff --git a/library/std/src/thread/mod.rs b/library/std/src/thread/mod.rs index d1d4eabb9bd..39753888509 100644 --- a/library/std/src/thread/mod.rs +++ b/library/std/src/thread/mod.rs @@ -519,9 +519,14 @@ impl Builder { let f = MaybeDangling::new(f); let main = move || { - // Immediately store the thread handle to avoid setting it or its ID - // twice, which would cause an abort. - set_current(their_thread.clone()); + if let Err(_thread) = set_current(their_thread.clone()) { + // Both the current thread handle and the ID should not be + // initialized yet. Since only the C runtime and some of our + // platform code run before this, this point shouldn't be + // reachable. Use an abort to save binary size (see #123356). + rtabort!("something here is badly broken!"); + } + if let Some(name) = their_thread.cname() { imp::Thread::set_name(name); } @@ -1159,9 +1164,6 @@ pub fn park_timeout(dur: Duration) { pub struct ThreadId(NonZero<u64>); impl ThreadId { - // DO NOT rely on this value. - const MAIN_THREAD: ThreadId = ThreadId(unsafe { NonZero::new_unchecked(1) }); - // Generate a new unique thread ID. pub(crate) fn new() -> ThreadId { #[cold] @@ -1173,7 +1175,7 @@ impl ThreadId { if #[cfg(target_has_atomic = "64")] { use crate::sync::atomic::AtomicU64; - static COUNTER: AtomicU64 = AtomicU64::new(1); + static COUNTER: AtomicU64 = AtomicU64::new(0); let mut last = COUNTER.load(Ordering::Relaxed); loop { @@ -1189,7 +1191,7 @@ impl ThreadId { } else { use crate::sync::{Mutex, PoisonError}; - static COUNTER: Mutex<u64> = Mutex::new(1); + static COUNTER: Mutex<u64> = Mutex::new(0); let mut counter = COUNTER.lock().unwrap_or_else(PoisonError::into_inner); let Some(id) = counter.checked_add(1) else { @@ -1326,9 +1328,9 @@ impl Thread { Self::new_inner(id, ThreadName::Unnamed) } - // Used in runtime to construct main thread - pub(crate) fn new_main() -> Thread { - Self::new_inner(ThreadId::MAIN_THREAD, ThreadName::Main) + /// Constructs the thread handle for the main thread. + pub(crate) fn new_main(id: ThreadId) -> Thread { + Self::new_inner(id, ThreadName::Main) } fn new_inner(id: ThreadId, name: ThreadName) -> Thread { |