diff --git a/Cargo.lock b/Cargo.lock index 0470bb552e8f2..f5aacba20cd23 100644 --- a/Cargo.lock +++ b/Cargo.lock @@ -2073,9 +2073,9 @@ checksum = "830d08ce1d1d941e6b30645f1a0eb5643013d835ce3779a5fc208261dbe10f55" [[package]] name = "libc" -version = "0.2.121" +version = "0.2.125" source = "registry+https://github.com/rust-lang/crates.io-index" -checksum = "efaa7b300f3b5fe8eb6bf21ce3895e1751d9665086af2d64b42f19701015ff4f" +checksum = "5916d2ae698f6de9bfb891ad7a8d65c09d232dc58cc4ac433c7da3b2fd84bc2b" dependencies = [ "rustc-std-workspace-core", ] diff --git a/library/std/Cargo.toml b/library/std/Cargo.toml index f2d6583206035..d0d7d480fe8e2 100644 --- a/library/std/Cargo.toml +++ b/library/std/Cargo.toml @@ -15,7 +15,7 @@ cfg-if = { version = "0.1.8", features = ['rustc-dep-of-std'] } panic_unwind = { path = "../panic_unwind", optional = true } panic_abort = { path = "../panic_abort" } core = { path = "../core" } -libc = { version = "0.2.116", default-features = false, features = ['rustc-dep-of-std'] } +libc = { version = "0.2.125", default-features = false, features = ['rustc-dep-of-std'] } compiler_builtins = { version = "0.1.71" } profiler_builtins = { path = "../profiler_builtins", optional = true } unwind = { path = "../unwind" } diff --git a/library/std/src/sync/condvar/tests.rs b/library/std/src/sync/condvar/tests.rs index f7a00676daaed..24f467f0b03d7 100644 --- a/library/std/src/sync/condvar/tests.rs +++ b/library/std/src/sync/condvar/tests.rs @@ -188,24 +188,3 @@ fn wait_timeout_wake() { break; } } - -#[test] -#[should_panic] -#[cfg(all(unix, not(target_os = "linux"), not(target_os = "android")))] -fn two_mutexes() { - let m = Arc::new(Mutex::new(())); - let m2 = m.clone(); - let c = Arc::new(Condvar::new()); - let c2 = c.clone(); - - let mut g = m.lock().unwrap(); - let _t = thread::spawn(move || { - let _g = m2.lock().unwrap(); - c2.notify_one(); - }); - g = c.wait(g).unwrap(); - drop(g); - - let m = Mutex::new(()); - let _ = c.wait(m.lock().unwrap()).unwrap(); -} diff --git a/library/std/src/sys/unix/futex.rs b/library/std/src/sys/unix/futex.rs index c12ee169e797a..678c6f0d6ead1 100644 --- a/library/std/src/sys/unix/futex.rs +++ b/library/std/src/sys/unix/futex.rs @@ -1,7 +1,10 @@ #![cfg(any( target_os = "linux", target_os = "android", - all(target_os = "emscripten", target_feature = "atomics") + all(target_os = "emscripten", target_feature = "atomics"), + target_os = "freebsd", + target_os = "openbsd", + target_os = "dragonfly", ))] use crate::sync::atomic::AtomicU32; @@ -12,7 +15,7 @@ use crate::time::Duration; /// Returns directly if the futex doesn't hold the expected value. /// /// Returns false on timeout, and true in all other cases. -#[cfg(any(target_os = "linux", target_os = "android"))] +#[cfg(any(target_os = "linux", target_os = "android", target_os = "freebsd"))] pub fn futex_wait(futex: &AtomicU32, expected: u32, timeout: Option) -> bool { use super::time::Timespec; use crate::ptr::null; @@ -30,18 +33,43 @@ pub fn futex_wait(futex: &AtomicU32, expected: u32, timeout: Option) - return true; } - // Use FUTEX_WAIT_BITSET rather than FUTEX_WAIT to be able to give an - // absolute time rather than a relative time. let r = unsafe { - libc::syscall( - libc::SYS_futex, - futex as *const AtomicU32, - libc::FUTEX_WAIT_BITSET | libc::FUTEX_PRIVATE_FLAG, - expected, - timespec.as_ref().map_or(null(), |t| &t.t as *const libc::timespec), - null::(), // This argument is unused for FUTEX_WAIT_BITSET. - !0u32, // A full bitmask, to make it behave like a regular FUTEX_WAIT. - ) + cfg_if::cfg_if! { + if #[cfg(target_os = "freebsd")] { + // FreeBSD doesn't have futex(), but it has + // _umtx_op(UMTX_OP_WAIT_UINT_PRIVATE), which is nearly + // identical. It supports absolute timeouts through a flag + // in the _umtx_time struct. + let umtx_timeout = timespec.map(|t| libc::_umtx_time { + _timeout: t.t, + _flags: libc::UMTX_ABSTIME, + _clockid: libc::CLOCK_MONOTONIC as u32, + }); + let umtx_timeout_ptr = umtx_timeout.as_ref().map_or(null(), |t| t as *const _); + let umtx_timeout_size = umtx_timeout.as_ref().map_or(0, |t| crate::mem::size_of_val(t)); + libc::_umtx_op( + futex as *const AtomicU32 as *mut _, + libc::UMTX_OP_WAIT_UINT_PRIVATE, + expected as libc::c_ulong, + crate::ptr::invalid_mut(umtx_timeout_size), + umtx_timeout_ptr as *mut _, + ) + } else if #[cfg(any(target_os = "linux", target_os = "android"))] { + // Use FUTEX_WAIT_BITSET rather than FUTEX_WAIT to be able to give an + // absolute time rather than a relative time. + libc::syscall( + libc::SYS_futex, + futex as *const AtomicU32, + libc::FUTEX_WAIT_BITSET | libc::FUTEX_PRIVATE_FLAG, + expected, + timespec.as_ref().map_or(null(), |t| &t.t as *const libc::timespec), + null::(), // This argument is unused for FUTEX_WAIT_BITSET. + !0u32, // A full bitmask, to make it behave like a regular FUTEX_WAIT. + ) + } else { + compile_error!("unknown target_os"); + } + } }; match (r < 0).then(super::os::errno) { @@ -56,31 +84,133 @@ pub fn futex_wait(futex: &AtomicU32, expected: u32, timeout: Option) - /// /// Returns true if this actually woke up such a thread, /// or false if no thread was waiting on this futex. +/// +/// On some platforms, this always returns false. +#[cfg(any(target_os = "linux", target_os = "android"))] +pub fn futex_wake(futex: &AtomicU32) -> bool { + let ptr = futex as *const AtomicU32; + let op = libc::FUTEX_WAKE | libc::FUTEX_PRIVATE_FLAG; + unsafe { libc::syscall(libc::SYS_futex, ptr, op, 1) > 0 } +} + +/// Wake up all threads that are waiting on futex_wait on this futex. #[cfg(any(target_os = "linux", target_os = "android"))] +pub fn futex_wake_all(futex: &AtomicU32) { + let ptr = futex as *const AtomicU32; + let op = libc::FUTEX_WAKE | libc::FUTEX_PRIVATE_FLAG; + unsafe { + libc::syscall(libc::SYS_futex, ptr, op, i32::MAX); + } +} + +// FreeBSD doesn't tell us how many threads are woken up, so this always returns false. +#[cfg(target_os = "freebsd")] pub fn futex_wake(futex: &AtomicU32) -> bool { + use crate::ptr::null_mut; unsafe { - libc::syscall( - libc::SYS_futex, - futex as *const AtomicU32, - libc::FUTEX_WAKE | libc::FUTEX_PRIVATE_FLAG, + libc::_umtx_op( + futex as *const AtomicU32 as *mut _, + libc::UMTX_OP_WAKE_PRIVATE, 1, - ) > 0 + null_mut(), + null_mut(), + ) + }; + false +} + +#[cfg(target_os = "freebsd")] +pub fn futex_wake_all(futex: &AtomicU32) { + use crate::ptr::null_mut; + unsafe { + libc::_umtx_op( + futex as *const AtomicU32 as *mut _, + libc::UMTX_OP_WAKE_PRIVATE, + i32::MAX as libc::c_ulong, + null_mut(), + null_mut(), + ) + }; +} + +#[cfg(target_os = "openbsd")] +pub fn futex_wait(futex: &AtomicU32, expected: u32, timeout: Option) -> bool { + use crate::convert::TryInto; + use crate::ptr::{null, null_mut}; + let timespec = timeout.and_then(|d| { + Some(libc::timespec { + // Sleep forever if the timeout is longer than fits in a timespec. + tv_sec: d.as_secs().try_into().ok()?, + // This conversion never truncates, as subsec_nanos is always <1e9. + tv_nsec: d.subsec_nanos() as _, + }) + }); + + let r = unsafe { + libc::futex( + futex as *const AtomicU32 as *mut u32, + libc::FUTEX_WAIT, + expected as i32, + timespec.as_ref().map_or(null(), |t| t as *const libc::timespec), + null_mut(), + ) + }; + + r == 0 || super::os::errno() != libc::ETIMEDOUT +} + +#[cfg(target_os = "openbsd")] +pub fn futex_wake(futex: &AtomicU32) -> bool { + use crate::ptr::{null, null_mut}; + unsafe { + libc::futex(futex as *const AtomicU32 as *mut u32, libc::FUTEX_WAKE, 1, null(), null_mut()) + > 0 } } -/// Wake up all threads that are waiting on futex_wait on this futex. -#[cfg(any(target_os = "linux", target_os = "android"))] +#[cfg(target_os = "openbsd")] pub fn futex_wake_all(futex: &AtomicU32) { + use crate::ptr::{null, null_mut}; unsafe { - libc::syscall( - libc::SYS_futex, - futex as *const AtomicU32, - libc::FUTEX_WAKE | libc::FUTEX_PRIVATE_FLAG, + libc::futex( + futex as *const AtomicU32 as *mut u32, + libc::FUTEX_WAKE, i32::MAX, + null(), + null_mut(), ); } } +#[cfg(target_os = "dragonfly")] +pub fn futex_wait(futex: &AtomicU32, expected: u32, timeout: Option) -> bool { + use crate::convert::TryFrom; + + // A timeout of 0 means infinite. + // We round smaller timeouts up to 1 millisecond. + // Overflows are rounded up to an infinite timeout. + let timeout_ms = + timeout.and_then(|d| Some(i32::try_from(d.as_millis()).ok()?.max(1))).unwrap_or(0); + + let r = unsafe { + libc::umtx_sleep(futex as *const AtomicU32 as *const i32, expected as i32, timeout_ms) + }; + + r == 0 || super::os::errno() != libc::ETIMEDOUT +} + +// DragonflyBSD doesn't tell us how many threads are woken up, so this always returns false. +#[cfg(target_os = "dragonfly")] +pub fn futex_wake(futex: &AtomicU32) -> bool { + unsafe { libc::umtx_wakeup(futex as *const AtomicU32 as *const i32, 1) }; + false +} + +#[cfg(target_os = "dragonfly")] +pub fn futex_wake_all(futex: &AtomicU32) { + unsafe { libc::umtx_wakeup(futex as *const AtomicU32 as *const i32, i32::MAX) }; +} + #[cfg(target_os = "emscripten")] extern "C" { fn emscripten_futex_wake(addr: *const AtomicU32, count: libc::c_int) -> libc::c_int; diff --git a/library/std/src/sys/unix/locks/futex_rwlock.rs b/library/std/src/sys/unix/locks/futex_rwlock.rs index e42edb2585834..57f6d58840db1 100644 --- a/library/std/src/sys/unix/locks/futex_rwlock.rs +++ b/library/std/src/sys/unix/locks/futex_rwlock.rs @@ -284,6 +284,10 @@ impl RwLock { fn wake_writer(&self) -> bool { self.writer_notify.fetch_add(1, Release); futex_wake(&self.writer_notify) + // Note that FreeBSD and DragonFlyBSD don't tell us whether they woke + // up any threads or not, and always return `false` here. That still + // results in correct behaviour: it just means readers get woken up as + // well in case both readers and writers were waiting. } /// Spin for a while, but stop directly at the given condition. diff --git a/library/std/src/sys/unix/locks/mod.rs b/library/std/src/sys/unix/locks/mod.rs index 3e39c8b9b23e7..04c5c489fc9b9 100644 --- a/library/std/src/sys/unix/locks/mod.rs +++ b/library/std/src/sys/unix/locks/mod.rs @@ -3,6 +3,9 @@ cfg_if::cfg_if! { target_os = "linux", target_os = "android", all(target_os = "emscripten", target_feature = "atomics"), + target_os = "freebsd", + target_os = "openbsd", + target_os = "dragonfly", ))] { mod futex; mod futex_rwlock; diff --git a/library/std/src/sys/unix/thread_parker.rs b/library/std/src/sys/unix/thread_parker.rs index fd83f2f73d6d6..cf37c01598bf3 100644 --- a/library/std/src/sys/unix/thread_parker.rs +++ b/library/std/src/sys/unix/thread_parker.rs @@ -3,7 +3,10 @@ #![cfg(not(any( target_os = "linux", target_os = "android", - all(target_os = "emscripten", target_feature = "atomics") + all(target_os = "emscripten", target_feature = "atomics"), + target_os = "freebsd", + target_os = "openbsd", + target_os = "dragonfly", )))] use crate::cell::UnsafeCell; diff --git a/library/std/src/sys_common/thread_parker/mod.rs b/library/std/src/sys_common/thread_parker/mod.rs index ea0204cd357ba..c789a388e05ad 100644 --- a/library/std/src/sys_common/thread_parker/mod.rs +++ b/library/std/src/sys_common/thread_parker/mod.rs @@ -3,6 +3,9 @@ cfg_if::cfg_if! { target_os = "linux", target_os = "android", all(target_arch = "wasm32", target_feature = "atomics"), + target_os = "freebsd", + target_os = "openbsd", + target_os = "dragonfly", ))] { mod futex; pub use futex::Parker;