Allow waitpid to be interrupted.

src/sync/wait_map.rs

@@ -26,14 +26,15 @@ where
         self.inner.lock().remove(key)
     }
 
-    pub fn receive(&self, key: &K, reason: &'static str) -> V {
+    pub fn receive(&self, key: &K, reason: &'static str) -> Option<V> {
         loop {
             let mut inner = self.inner.lock();
             if let Some(value) = inner.remove(key) {
-                return value;
+                return Some(value);
+            }
+            if !self.condition.wait(inner, reason) {
+                return None;
             }
-            //TODO: use false from wait condition to indicate EINTR
-            let _ = self.condition.wait(inner, reason);
         }
     }
 

src/syscall/process.rs

@@ -674,13 +674,15 @@ pub fn waitpid(
                     Some(Ok(ProcessId::from(0)))
                 }
             } else {
-                let (w_pid, status) = waitpid.receive(
-                    &WaitpidKey {
-                        pid: None,
-                        pgid: Some(pgid),
-                    },
-                    "waitpid pgid",
-                );
+                let (w_pid, status) = waitpid
+                    .receive(
+                        &WaitpidKey {
+                            pid: None,
+                            pgid: Some(pgid),
+                        },
+                        "waitpid pgid",
+                    )
+                    .ok_or(Error::new(EINTR))?;
                 grim_reaper(w_pid, status)
             }
         } else {
@@ -716,13 +718,15 @@ pub fn waitpid(
                     Some(Ok(ProcessId::from(0)))
                 }
             } else {
-                let (w_pid, status) = waitpid.receive(
-                    &WaitpidKey {
-                        pid: Some(pid),
-                        pgid: None,
-                    },
-                    "waitpid pid",
-                );
+                let (w_pid, status) = waitpid
+                    .receive(
+                        &WaitpidKey {
+                            pid: Some(pid),
+                            pgid: None,
+                        },
+                        "waitpid pid",
+                    )
+                    .ok_or(Error::new(EINTR))?;
                 grim_reaper(w_pid, status)
             }
         };