Merge pull request #775 from pjbgf/leak-conns

libgit2: dispose connections in SubTransport.Close

Author: Paulo Gomes

pkg/git/libgit2/managed/ssh.go

@@ -95,12 +95,11 @@ type sshSmartSubtransport struct {
 }
 
 type connection struct {
-	conn          net.Conn
 	client        *ssh.Client
 	session       *ssh.Session
 	currentStream *sshSmartSubtransportStream
 	connected     bool
-	m             sync.Mutex
+	m             sync.RWMutex
 }
 
 func (t *sshSmartSubtransport) Action(transportOptionsURL string, action git2go.SmartServiceAction) (git2go.SmartSubtransportStream, error) {
@@ -155,11 +154,6 @@ func (t *sshSmartSubtransport) Action(transportOptionsURL string, action git2go.
 		return nil, fmt.Errorf("unexpected action: %v", action)
 	}
 
-	if t.con.connected {
-		// Disregard errors from previous stream, futher details inside Close().
-		_ = t.Close()
-	}
-
 	port := "22"
 	if u.Port() != "" {
 		port = u.Port()
@@ -189,13 +183,18 @@ func (t *sshSmartSubtransport) Action(transportOptionsURL string, action git2go.
 		return nil
 	}
 
+	t.con.m.RLock()
+	if t.con.connected == true {
+		// The connection is no longer shared across actions, so ensures
+		// all has been released before starting a new connection.
+		_ = t.Close()
+	}
+	t.con.m.RUnlock()
+
 	err = t.createConn(t.addr, sshConfig)
 	if err != nil {
 		return nil, err
 	}
-	t.con.m.Lock()
-	t.con.connected = true
-	t.con.m.Unlock()
 
 	traceLog.Info("[ssh]: creating new ssh session")
 	if t.con.session, err = t.con.client.NewSession(); err != nil {
@@ -244,12 +243,12 @@ func (t *sshSmartSubtransport) Action(transportOptionsURL string, action git2go.
 				return nil
 
 			default:
-				t.con.m.Lock()
+				t.con.m.RLock()
 				if !t.con.connected {
-					t.con.m.Unlock()
+					t.con.m.RUnlock()
 					return nil
 				}
-				t.con.m.Unlock()
+				t.con.m.RUnlock()
 
 				_, err := io.Copy(w, reader)
 				if err != nil {
@@ -286,8 +285,10 @@ func (t *sshSmartSubtransport) createConn(addr string, sshConfig *ssh.ClientConf
 		return err
 	}
 
-	t.con.conn = conn
+	t.con.m.Lock()
+	t.con.connected = true
 	t.con.client = ssh.NewClient(c, chans, reqs)
+	t.con.m.Unlock()
 
 	return nil
 }
@@ -309,29 +310,24 @@ func (t *sshSmartSubtransport) Close() error {
 	if t.con.client != nil && t.stdin != nil {
 		_ = t.stdin.Close()
 	}
-	t.con.client = nil
+	t.stdin = nil
 
 	if t.con.session != nil {
 		traceLog.Info("[ssh]: session.Close()", "server", t.addr)
 		_ = t.con.session.Close()
 	}
 	t.con.session = nil
 
-	return nil
-}
-
-func (t *sshSmartSubtransport) Free() {
-	traceLog.Info("[ssh]: sshSmartSubtransport.Free()")
 	if t.con.client != nil {
 		_ = t.con.client.Close()
 	}
 
-	if t.con.conn != nil {
-		_ = t.con.conn.Close()
-	}
-	t.con.m.Lock()
 	t.con.connected = false
-	t.con.m.Unlock()
+
+	return nil
+}
+
+func (t *sshSmartSubtransport) Free() {
 }
 
 type sshSmartSubtransportStream struct {