use crate::sys::cvt_nz;
use crate::sys_common::lazy_box::{LazyBox, LazyInit};
+struct AllocatedMutex(UnsafeCell<libc::pthread_mutex_t>);
+
pub struct Mutex {
- inner: UnsafeCell<libc::pthread_mutex_t>,
+ inner: LazyBox<AllocatedMutex>,
}
-pub(crate) type MovableMutex = LazyBox<Mutex>;
-
#[inline]
pub unsafe fn raw(m: &Mutex) -> *mut libc::pthread_mutex_t {
- m.inner.get()
+ m.inner.0.get()
}
-unsafe impl Send for Mutex {}
-unsafe impl Sync for Mutex {}
+unsafe impl Send for AllocatedMutex {}
+unsafe impl Sync for AllocatedMutex {}
-impl LazyInit for Mutex {
+impl LazyInit for AllocatedMutex {
fn init() -> Box<Self> {
- let mut mutex = Box::new(Self::new());
- unsafe { mutex.init() };
- mutex
- }
-
- fn destroy(mutex: Box<Self>) {
- // We're not allowed to pthread_mutex_destroy a locked mutex,
- // so check first if it's unlocked.
- if unsafe { mutex.try_lock() } {
- unsafe { mutex.unlock() };
- drop(mutex);
- } else {
- // The mutex is locked. This happens if a MutexGuard is leaked.
- // In this case, we just leak the Mutex too.
- forget(mutex);
- }
- }
-
- fn cancel_init(_: Box<Self>) {
- // In this case, we can just drop it without any checks,
- // since it cannot have been locked yet.
- }
-}
+ let mutex = Box::new(AllocatedMutex(UnsafeCell::new(libc::PTHREAD_MUTEX_INITIALIZER)));
-impl Mutex {
- pub const fn new() -> Mutex {
- // Might be moved to a different address, so it is better to avoid
- // initialization of potentially opaque OS data before it landed.
- // Be very careful using this newly constructed `Mutex`, reentrant
- // locking is undefined behavior until `init` is called!
- Mutex { inner: UnsafeCell::new(libc::PTHREAD_MUTEX_INITIALIZER) }
- }
- #[inline]
- unsafe fn init(&mut self) {
// Issue #33770
//
// A pthread mutex initialized with PTHREAD_MUTEX_INITIALIZER will have
// references, we instead create the mutex with type
// PTHREAD_MUTEX_NORMAL which is guaranteed to deadlock if we try to
// re-lock it from the same thread, thus avoiding undefined behavior.
- let mut attr = MaybeUninit::<libc::pthread_mutexattr_t>::uninit();
- cvt_nz(libc::pthread_mutexattr_init(attr.as_mut_ptr())).unwrap();
- let attr = PthreadMutexAttr(&mut attr);
- cvt_nz(libc::pthread_mutexattr_settype(attr.0.as_mut_ptr(), libc::PTHREAD_MUTEX_NORMAL))
+ unsafe {
+ let mut attr = MaybeUninit::<libc::pthread_mutexattr_t>::uninit();
+ cvt_nz(libc::pthread_mutexattr_init(attr.as_mut_ptr())).unwrap();
+ let attr = PthreadMutexAttr(&mut attr);
+ cvt_nz(libc::pthread_mutexattr_settype(
+ attr.0.as_mut_ptr(),
+ libc::PTHREAD_MUTEX_NORMAL,
+ ))
.unwrap();
- cvt_nz(libc::pthread_mutex_init(self.inner.get(), attr.0.as_ptr())).unwrap();
+ cvt_nz(libc::pthread_mutex_init(mutex.0.get(), attr.0.as_ptr())).unwrap();
+ }
+
+ mutex
}
- #[inline]
- pub unsafe fn lock(&self) {
- let r = libc::pthread_mutex_lock(self.inner.get());
- debug_assert_eq!(r, 0);
+
+ fn destroy(mutex: Box<Self>) {
+ // We're not allowed to pthread_mutex_destroy a locked mutex,
+ // so check first if it's unlocked.
+ if unsafe { libc::pthread_mutex_trylock(mutex.0.get()) == 0 } {
+ unsafe { libc::pthread_mutex_unlock(mutex.0.get()) };
+ drop(mutex);
+ } else {
+ // The mutex is locked. This happens if a MutexGuard is leaked.
+ // In this case, we just leak the Mutex too.
+ forget(mutex);
+ }
}
+
+ fn cancel_init(_: Box<Self>) {
+ // In this case, we can just drop it without any checks,
+ // since it cannot have been locked yet.
+ }
+}
+
+impl Drop for AllocatedMutex {
#[inline]
- pub unsafe fn unlock(&self) {
- let r = libc::pthread_mutex_unlock(self.inner.get());
- debug_assert_eq!(r, 0);
+ fn drop(&mut self) {
+ let r = unsafe { libc::pthread_mutex_destroy(self.0.get()) };
+ if cfg!(target_os = "dragonfly") {
+ // On DragonFly pthread_mutex_destroy() returns EINVAL if called on a
+ // mutex that was just initialized with libc::PTHREAD_MUTEX_INITIALIZER.
+ // Once it is used (locked/unlocked) or pthread_mutex_init() is called,
+ // this behaviour no longer occurs.
+ debug_assert!(r == 0 || r == libc::EINVAL);
+ } else {
+ debug_assert_eq!(r, 0);
+ }
}
+}
+
+impl Mutex {
#[inline]
- pub unsafe fn try_lock(&self) -> bool {
- libc::pthread_mutex_trylock(self.inner.get()) == 0
+ pub const fn new() -> Mutex {
+ Mutex { inner: LazyBox::new() }
}
+
#[inline]
- #[cfg(not(target_os = "dragonfly"))]
- unsafe fn destroy(&mut self) {
- let r = libc::pthread_mutex_destroy(self.inner.get());
+ pub unsafe fn lock(&self) {
+ let r = libc::pthread_mutex_lock(raw(self));
debug_assert_eq!(r, 0);
}
+
#[inline]
- #[cfg(target_os = "dragonfly")]
- unsafe fn destroy(&mut self) {
- let r = libc::pthread_mutex_destroy(self.inner.get());
- // On DragonFly pthread_mutex_destroy() returns EINVAL if called on a
- // mutex that was just initialized with libc::PTHREAD_MUTEX_INITIALIZER.
- // Once it is used (locked/unlocked) or pthread_mutex_init() is called,
- // this behaviour no longer occurs.
- debug_assert!(r == 0 || r == libc::EINVAL);
+ pub unsafe fn unlock(&self) {
+ let r = libc::pthread_mutex_unlock(raw(self));
+ debug_assert_eq!(r, 0);
}
-}
-impl Drop for Mutex {
#[inline]
- fn drop(&mut self) {
- unsafe { self.destroy() };
+ pub unsafe fn try_lock(&self) -> bool {
+ libc::pthread_mutex_trylock(raw(self)) == 0
}
}
projects / rustc.git / blobdiff