ssh system commands: wait on write from command out to network

we only need to wait for the write from the local command to
the ssh channel. There is no need to wait for the write from ssh
channel to the local command stdin

sftpd/sftpd.go

@@ -424,7 +424,7 @@ func executeAction(operation, username, path, target, sshCmd string) error {
 		if _, err = os.Stat(actions.Command); err == nil {
 			command := exec.Command(actions.Command, operation, username, path, target, sshCmd)
 			err = command.Start()
-			logger.Debug(logSender, "", "start command %#v with arguments: %v, %v, %v, %v %v, error: %v",
+			logger.Debug(logSender, "", "start command %#v with arguments: %#v, %#v, %#v, %#v, %#v, error: %v",
 				actions.Command, operation, username, path, target, sshCmd, err)
 			if err == nil {
 				// we are in a goroutine but we don't want to block here, this way we can send the

sftpd/ssh_cmd.go

@@ -174,8 +174,7 @@ func (c *sshCommand) executeSystemCommand(command systemCommand) error {
 		c.connection.channel.Close()
 	}
 	var once sync.Once
-	var wg sync.WaitGroup
-	wg.Add(2)
+	commandResponse := make(chan bool)
 
 	go func() {
 		defer stdin.Close()
@@ -207,7 +206,6 @@ func (c *sshCommand) executeSystemCommand(command systemCommand) error {
 		if e != nil {
 			once.Do(closeCmdOnError)
 		}
-		wg.Done()
 	}()
 
 	go func() {
@@ -235,7 +233,7 @@ func (c *sshCommand) executeSystemCommand(command systemCommand) error {
 		if e != nil {
 			once.Do(closeCmdOnError)
 		}
-		wg.Done()
+		commandResponse <- true
 	}()
 
 	go func() {
@@ -265,7 +263,7 @@ func (c *sshCommand) executeSystemCommand(command systemCommand) error {
 		}
 	}()
 
-	wg.Wait()
+	<-commandResponse
 	err = command.cmd.Wait()
 	c.sendExitStatus(err)
 	c.rescanHomeDir()
@@ -290,7 +288,7 @@ func (c *sshCommand) getSystemCommand() (systemCommand, error) {
 		args = args[:len(args)-1]
 		args = append(args, path)
 	}
-	c.connection.Log(logger.LevelDebug, logSenderSSH, "new system command: %v, with args: %v path: %v", c.command, args, path)
+	c.connection.Log(logger.LevelDebug, logSenderSSH, "new system command %#v, with args: %v path: %v", c.command, args, path)
 	cmd := exec.Command(c.command, args...)
 	uid := c.connection.User.GetUID()
 	gid := c.connection.User.GetGID()