fix broken pipe status. rustc works now!

kernel/src/fs/pipe.rs

@@ -45,13 +45,25 @@ impl Pipe {
         )
     }
 
-    pub fn can_read(&self) -> bool {
+    fn can_read(&self) -> bool {
         if let PipeEnd::Read = self.direction {
-            self.data.lock().buf.len() > 0
+            self.data.lock().buf.len() > 0 || self.is_broken()
         } else {
             false
         }
     }
+
+    fn can_write(&self) -> bool {
+        if let PipeEnd::Write = self.direction {
+            !self.is_broken()
+        } else {
+            false
+        }
+    }
+
+    fn is_broken(&self) -> bool {
+        Arc::strong_count(&self.data) < 2
+    }
 }
 
 // TODO: better way to provide default impl?
@@ -105,39 +117,11 @@ impl INode for Pipe {
     }
 
     fn poll(&self) -> Result<PollStatus> {
-        let data = self.data.lock();
-        match self.direction {
-            PipeEnd::Read => {
-                if data.buf.len() > 0 {
-                    Ok(PollStatus {
-                        read: true,
-                        write: false,
-                        error: false,
-                    })
-                } else {
-                    Ok(PollStatus {
-                        read: false,
-                        write: false,
-                        error: false,
-                    })
-                }
-            }
-            PipeEnd::Write => {
-                if data.buf.len() > 0 {
-                    Ok(PollStatus {
-                        read: false,
-                        write: true,
-                        error: false,
-                    })
-                } else {
-                    Ok(PollStatus {
-                        read: false,
-                        write: false,
-                        error: false,
-                    })
-                }
-            }
-        }
+        Ok(PollStatus {
+            read: self.can_read(),
+            write: self.can_write(),
+            error: false,
+        })
     }
     impl_inode!();
 }

kernel/src/syscall/fs.rs

@@ -141,6 +141,9 @@ impl Syscall<'_> {
                 return Ok(0);
             }
 
+            // NOTE: To run rustc, uncomment yield_now and comment Condvar.
+            //       Waking up from pipe is unimplemented now.
+            // thread::yield_now();
             Condvar::wait_any(&[&STDIN.pushed, &(*SOCKET_ACTIVITY)]);
         }
     }
@@ -1416,6 +1419,7 @@ impl IoVecs {
 }
 
 #[repr(C)]
+#[derive(Debug)]
 pub struct PollFd {
     fd: u32,
     events: PollEvents,

kernel/src/syscall/misc.rs

@@ -69,10 +69,9 @@ impl Syscall<'_> {
             val,
             timeout
         );
-        //    if op & OP_PRIVATE == 0 {
-        //        unimplemented!("futex only support process-private");
-        //        return Err(SysError::ENOSYS);
-        //    }
+        if op & OP_PRIVATE == 0 {
+            warn!("process-shared futex is unimplemented");
+        }
         if uaddr % size_of::<u32>() != 0 {
             return Err(SysError::EINVAL);
         }
@@ -80,7 +79,7 @@ impl Syscall<'_> {
 
         const OP_WAIT: u32 = 0;
         const OP_WAKE: u32 = 1;
-        const OP_PRIVATE: u32 = 128;
+        const OP_PRIVATE: u32 = 0x80;
 
         let mut proc = self.process();
         let queue = proc.get_futex(uaddr);