Merge pull request #270 from crosbymichael/shim-start-error

Return the start error and reap

containerd-shim/main.go

@@ -17,6 +17,12 @@ func writeMessage(f *os.File, level string, err error) {
 	fmt.Fprintf(f, `{"level": "%s","msg": "%s"}`, level, err)
 }
 
+type controlMessage struct {
+	Type   int
+	Width  int
+	Height int
+}
+
 // containerd-shim is a small shim that sits in front of a runtime implementation
 // that allows it to be repartented to init and handle reattach from the caller.
 //
@@ -82,37 +88,20 @@ func start(log *os.File) error {
 		p.delete()
 		return err
 	}
+	msgC := make(chan controlMessage, 32)
 	go func() {
 		for {
-			var msg, w, h int
-			if _, err := fmt.Fscanf(control, "%d %d %d\n", &msg, &w, &h); err != nil {
+			var m controlMessage
+			if _, err := fmt.Fscanf(control, "%d %d %d\n", &m.Type, &m.Width, &m.Height); err != nil {
 				continue
 			}
-			switch msg {
-			case 0:
-				// close stdin
-				if p.stdinCloser != nil {
-					p.stdinCloser.Close()
-				}
-			case 1:
-				if p.console == nil {
-					continue
-				}
-				ws := term.Winsize{
-					Width:  uint16(w),
-					Height: uint16(h),
-				}
-				term.SetWinsize(p.console.Fd(), &ws)
-			case 2:
-				// tell runtime to execute the init process
-				if err := p.start(); err != nil {
-					syscall.Kill(p.pid(), syscall.SIGKILL)
-				}
-			}
+			msgC <- m
 		}
 	}()
 	var exitShim bool
-	for s := range signals {
+	for {
+		select {
+		case s := <-signals:
 			switch s {
 			case syscall.SIGCHLD:
 				exits, _ := osutils.Reap()
@@ -131,6 +120,31 @@ func start(log *os.File) error {
 				p.Wait()
 				return nil
 			}
+		case msg := <-msgC:
+			switch msg.Type {
+			case 0:
+				// close stdin
+				if p.stdinCloser != nil {
+					p.stdinCloser.Close()
+				}
+			case 1:
+				if p.console == nil {
+					continue
+				}
+				ws := term.Winsize{
+					Width:  uint16(msg.Width),
+					Height: uint16(msg.Height),
+				}
+				term.SetWinsize(p.console.Fd(), &ws)
+			case 2:
+				// tell runtime to execute the init process
+				if err := p.start(); err != nil {
+					p.delete()
+					p.Wait()
+					return err
+				}
+			}
+		}
 	}
 	return nil
 }