From 50f6382307d8574cba170a2b0b12e4dc948f6d05 Mon Sep 17 00:00:00 2001
From: Alessandro Arzilli <alessandro.arzilli@gmail.com>
Date: Mon, 26 Jun 2017 20:45:13 +0200
Subject: [PATCH] dlv: make headless servers quit automatically when client
 disconnects (#895)

---
 cmd/dlv/cmds/commands.go        |  9 ++++++++-
 cmd/dlv/dlv_test.go             | 15 +++------------
 pkg/proc/gdbserial/gdbserver.go |  1 +
 service/config.go               |  3 +++
 service/rpc2/client.go          |  1 +
 service/rpccommon/server.go     |  3 +++
 6 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/cmd/dlv/cmds/commands.go b/cmd/dlv/cmds/commands.go
index 79a94b11..83ad7bcf 100644
--- a/cmd/dlv/cmds/commands.go
+++ b/cmd/dlv/cmds/commands.go
@@ -455,6 +455,8 @@ func execute(attachPid int, processArgs []string, conf *config.Config, coreFile
 		Stop(bool) error
 	}
 
+	disconnectChan := make(chan struct{})
+
 	// Create and start a debugger server
 	switch APIVersion {
 	case 1, 2:
@@ -467,6 +469,8 @@ func execute(attachPid int, processArgs []string, conf *config.Config, coreFile
 			WorkingDir:  WorkingDir,
 			Backend:     Backend,
 			CoreFile:    coreFile,
+
+			DisconnectChan: disconnectChan,
 		}, Log)
 	default:
 		fmt.Printf("Unknown API version: %d\n", APIVersion)
@@ -496,7 +500,10 @@ func execute(attachPid int, processArgs []string, conf *config.Config, coreFile
 		fmt.Printf("API server listening at: %s\n", listener.Addr())
 		ch := make(chan os.Signal)
 		signal.Notify(ch, syscall.SIGINT)
-		<-ch
+		select {
+		case <-ch:
+		case <-disconnectChan:
+		}
 		err = server.Stop(true)
 	} else {
 		// Create and start a terminal
diff --git a/cmd/dlv/dlv_test.go b/cmd/dlv/dlv_test.go
index 7ebfe4e7..471daba9 100644
--- a/cmd/dlv/dlv_test.go
+++ b/cmd/dlv/dlv_test.go
@@ -76,17 +76,6 @@ func TestBuild(t *testing.T) {
 	stdout, err := cmd.StdoutPipe()
 	assertNoError(err, t, "stdout pipe")
 	cmd.Start()
-	done := make(chan struct{})
-	defer func() {
-		if runtime.GOOS != "windows" {
-			cmd.Process.Signal(os.Interrupt)
-		} else {
-			// sending os.Interrupt on windows is not supported
-			cmd.Process.Kill()
-		}
-		<-done
-		cmd.Wait()
-	}()
 
 	scan := bufio.NewScanner(stdout)
 	// wait for the debugger to start
@@ -95,7 +84,6 @@ func TestBuild(t *testing.T) {
 		for scan.Scan() {
 			// keep pipe empty
 		}
-		close(done)
 	}()
 
 	client := rpc2.NewClient(listenAddr)
@@ -104,4 +92,7 @@ func TestBuild(t *testing.T) {
 	if !state.Exited {
 		t.Fatal("Program did not exit")
 	}
+
+	client.Detach(true)
+	cmd.Wait()
 }
diff --git a/pkg/proc/gdbserial/gdbserver.go b/pkg/proc/gdbserial/gdbserver.go
index bf9670dd..4df8f19d 100644
--- a/pkg/proc/gdbserial/gdbserver.go
+++ b/pkg/proc/gdbserial/gdbserver.go
@@ -698,6 +698,7 @@ func (p *Process) Detach(kill bool) error {
 	if p.process != nil {
 		p.process.Kill()
 		<-p.waitChan
+		p.process = nil
 	}
 	return p.bi.Close()
 }
diff --git a/service/config.go b/service/config.go
index 42741b80..ecd40826 100644
--- a/service/config.go
+++ b/service/config.go
@@ -31,4 +31,7 @@ type Config struct {
 
 	// Selects server backend.
 	Backend string
+
+	// DisconnectChan will be closed by the server when the client disconnects
+	DisconnectChan chan<- struct{}
 }
diff --git a/service/rpc2/client.go b/service/rpc2/client.go
index 0a8c0320..eb31cfd6 100644
--- a/service/rpc2/client.go
+++ b/service/rpc2/client.go
@@ -45,6 +45,7 @@ func (c *RPCClient) LastModified() time.Time {
 }
 
 func (c *RPCClient) Detach(kill bool) error {
+	defer c.client.Close()
 	out := new(DetachOut)
 	return c.call("Detach", DetachIn{kill}, out)
 }
diff --git a/service/rpccommon/server.go b/service/rpccommon/server.go
index 7c9e9235..b89948e0 100644
--- a/service/rpccommon/server.go
+++ b/service/rpccommon/server.go
@@ -321,6 +321,9 @@ func (s *ServerImpl) serveJSONCodec(conn io.ReadWriteCloser) {
 		}
 	}
 	codec.Close()
+	if !s.config.AcceptMulti && s.config.DisconnectChan != nil {
+		close(s.config.DisconnectChan)
+	}
 }
 
 // A value sent as a placeholder for the server's response value when the server