grpc: Ignore WriteStdin after the standard input has been closed

After CloseStdin() has been invoked, there is no reason to accept writing to stdin anymore. Instead, we can simply ignore those calls. Fixes kata-containers#283 Signed-off-by: Sebastien Boeuf <[email protected]>
zklei · Jul 5, 2018 · ed656df · ed656df
1 parent 1a52204
commit ed656df
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diff --git a/agent.go b/agent.go
@@ -58,6 +58,8 @@ var initRootfsMounts = []initMount{
 }
 
 type process struct {
+	sync.RWMutex
+
 	id          string
 	process     libcontainer.Process
 	stdin       *os.File
@@ -66,6 +68,7 @@ type process struct {
 	consoleSock *os.File
 	termMaster  *os.File
 	exitCodeCh  chan int
+	stdinClosed bool
 }
 
 type container struct {

diff --git a/grpc.go b/grpc.go
@@ -1044,6 +1044,16 @@ func (a *agentGRPC) WriteStdin(ctx context.Context, req *pb.WriteStreamRequest)
 		return &pb.WriteStreamResponse{}, err
 	}
 
+	proc.RLock()
+	defer proc.RUnlock()
+	stdinClosed := proc.stdinClosed
+
+	// Ignore this call to WriteStdin() if STDIN has already been closed
+	// earlier.
+	if stdinClosed {
+		return &pb.WriteStreamResponse{}, nil
+	}
+
 	var file *os.File
 	if proc.termMaster != nil {
 		file = proc.termMaster
@@ -1095,10 +1105,15 @@ func (a *agentGRPC) CloseStdin(ctx context.Context, req *pb.CloseStdinRequest) (
 		return emptyResp, nil
 	}
 
+	proc.Lock()
+	defer proc.Unlock()
+
 	if err := proc.stdin.Close(); err != nil {
 		return emptyResp, err
 	}
 
+	proc.stdinClosed = true
+
 	return emptyResp, nil
 }