From f4a38c0e16841dcb4e814ca570f63933663a1f8f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Kr=C3=B6ning?= <mkroening@posteo.net>
Date: Sat, 29 May 2021 22:16:10 +0200
Subject: [PATCH] hermit: Implement Condvar::wait_timeout

---
 library/std/src/sys/hermit/condvar.rs | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/library/std/src/sys/hermit/condvar.rs b/library/std/src/sys/hermit/condvar.rs
index b45e8718f088e..e22e1efba6fdb 100644
--- a/library/std/src/sys/hermit/condvar.rs
+++ b/library/std/src/sys/hermit/condvar.rs
@@ -55,8 +55,18 @@ impl Condvar {
         mutex.lock();
     }
 
-    pub unsafe fn wait_timeout(&self, _mutex: &Mutex, _dur: Duration) -> bool {
-        panic!("wait_timeout not supported on hermit");
+    pub unsafe fn wait_timeout(&self, mutex: &Mutex, dur: Duration) -> bool {
+        if dur.is_zero() {
+            return false;
+        }
+
+        self.counter.fetch_add(1, SeqCst);
+        mutex.unlock();
+        let millis = dur.as_millis().min(u32::MAX as u128) as u32;
+        let success = abi::sem_timedwait(self.sem1, millis) == 0;
+        abi::sem_post(self.sem2);
+        mutex.lock();
+        success
     }
 
     pub unsafe fn destroy(&self) {