From ba66bb2e818bd33c3c5e93a2b5d58eb9fb728b50 Mon Sep 17 00:00:00 2001
From: Thomas Hallgren <thomas@tada.se>
Date: Sun, 21 Aug 2022 14:23:01 +0200
Subject: [PATCH] fix(MLST): Prefix MLST entries with a space (#353)
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* Prefix MLST entries with a space
* Fix lint issue in handleMLST
* Rename ẁriteMLSxOutput to writeMLSxEntry

Signed-off-by: Thomas Hallgren <thomas@datawire.io>
---
 handle_dirs.go       |  4 ++--
 handle_files.go      | 11 +++++++----
 handle_files_test.go | 34 ++++++++++++++++++++++++++++++++++
 3 files changed, 43 insertions(+), 6 deletions(-)

diff --git a/handle_dirs.go b/handle_dirs.go
index 96cb592d..e2c9cbb0 100644
--- a/handle_dirs.go
+++ b/handle_dirs.go
@@ -285,14 +285,14 @@ func (c *clientHandler) dirTransferMLSD(w io.Writer, files []os.FileInfo) error
 	}
 
 	for _, file := range files {
-		if err := c.writeMLSxOutput(w, file); err != nil {
+		if err := c.writeMLSxEntry(w, file); err != nil {
 			return err
 		}
 	}
 
 	return nil
 }
-func (c *clientHandler) writeMLSxOutput(w io.Writer, file os.FileInfo) error {
+func (c *clientHandler) writeMLSxEntry(w io.Writer, file os.FileInfo) error {
 	var listType string
 	if file.IsDir() {
 		listType = "dir"
diff --git a/handle_files.go b/handle_files.go
index d6d640ef..581ff315 100644
--- a/handle_files.go
+++ b/handle_files.go
@@ -466,17 +466,20 @@ func (c *clientHandler) handleMLST(param string) error {
 
 	path := c.absPath(param)
 
-	if info, err := c.driver.Stat(path); err == nil {
+	info, err := c.driver.Stat(path)
+	if err == nil {
 		defer c.multilineAnswer(StatusFileOK, "File details")()
 
-		if errWrite := c.writeMLSxOutput(c.writer, info); errWrite != nil {
-			return errWrite
+		// Each MLSx entry must start with a space when returned in a multiline answer
+		if err = c.writer.WriteByte(' '); err == nil {
+			err = c.writeMLSxEntry(c.writer, info)
 		}
 	} else {
 		c.writeMessage(StatusActionNotTaken, fmt.Sprintf("Could not list: %v", err))
+		err = nil
 	}
 
-	return nil
+	return err
 }
 
 func (c *clientHandler) handleALLO(param string) error {
diff --git a/handle_files_test.go b/handle_files_test.go
index 60736e24..e6a10902 100644
--- a/handle_files_test.go
+++ b/handle_files_test.go
@@ -362,6 +362,40 @@ func TestSTATFile(t *testing.T) {
 	require.Equal(t, StatusFileActionNotTaken, rc)
 }
 
+func TestMLST(t *testing.T) {
+	s := NewTestServer(t, true)
+	conf := goftp.Config{
+		User:     authUser,
+		Password: authPass,
+	}
+	c, err := goftp.DialConfig(conf, s.Addr())
+	require.NoError(t, err, "Couldn't connect")
+
+	defer func() { panicOnError(c.Close()) }()
+
+	// Creating a tiny file
+	ftpUpload(t, c, createTemporaryFile(t, 10), "file")
+
+	raw, err := c.OpenRawConn()
+	require.NoError(t, err, "Couldn't open raw connection")
+
+	defer func() { require.NoError(t, raw.Close()) }()
+
+	rc, rsp, err := raw.SendCommand("MLST file")
+	require.NoError(t, err)
+	require.Equal(t, StatusFileOK, rc)
+
+	lines := strings.Split(rsp, "\n")
+	require.Len(t, lines, 3)
+	path := validMLSxEntryPattern.FindStringSubmatch(lines[1] + "\r\n")
+
+	if len(path) != 2 {
+		t.Errorf("Valid MLST response example did not pass validation: \"%s\"", lines[1])
+	} else if path[1] != "file" {
+		t.Errorf("Validation returned incorrect pathentry: got \"%s\", want \"%s\"", path, "file")
+	}
+}
+
 func TestMDTM(t *testing.T) {
 	s := NewTestServer(t, true)
 	conf := goftp.Config{