lib: Folder marker is now a folder

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/4341
LGTM: calmh

lib/config/config.go

@@ -32,7 +32,7 @@ import (
 
 const (
 	OldestHandledVersion = 10
-	CurrentVersion       = 22
+	CurrentVersion       = 23
 	MaxRescanIntervalS   = 365 * 24 * 60 * 60
 )
 
@@ -323,6 +323,9 @@ func (cfg *Configuration) clean() error {
 	if cfg.Version == 21 {
 		convertV21V22(cfg)
 	}
+	if cfg.Version == 22 {
+		convertV22V23(cfg)
+	}
 
 	// Build a list of available devices
 	existingDevices := make(map[protocol.DeviceID]bool)
@@ -372,6 +375,33 @@ func (cfg *Configuration) clean() error {
 	return nil
 }
 
+func convertV22V23(cfg *Configuration) {
+	permBits := fs.FileMode(0777)
+	if runtime.GOOS == "windows" {
+		// Windows has no umask so we must chose a safer set of bits to
+		// begin with.
+		permBits = 0700
+	}
+	for i := range cfg.Folders {
+		fs := cfg.Folders[i].Filesystem()
+		// Invalid config posted, or tests.
+		if fs == nil {
+			continue
+		}
+		if stat, err := fs.Stat(".stfolder"); err == nil && !stat.IsDir() {
+			err = fs.Remove(".stfolder")
+			if err == nil {
+				err = fs.Mkdir(".stfolder", permBits)
+			}
+			if err != nil {
+				l.Fatalln("failed to upgrade folder marker:", err)
+			}
+		}
+	}
+
+	cfg.Version = 23
+}
+
 func convertV21V22(cfg *Configuration) {
 	for i := range cfg.Folders {
 		cfg.Folders[i].FilesystemType = fs.FilesystemTypeBasic

lib/config/config_test.go

@@ -86,7 +86,7 @@ func TestDefaultValues(t *testing.T) {
 
 func TestDeviceConfig(t *testing.T) {
 	for i := OldestHandledVersion; i <= CurrentVersion; i++ {
-		os.Remove("testdata/.stfolder")
+		os.RemoveAll("testdata/.stfolder")
 		wr, err := Load(fmt.Sprintf("testdata/v%d.xml", i), device1)
 		if err != nil {
 			t.Fatal(err)

lib/config/folderconfiguration.go

@@ -81,12 +81,17 @@ func (f FolderConfiguration) Filesystem() fs.Filesystem {
 
 func (f *FolderConfiguration) CreateMarker() error {
 	if !f.HasMarker() {
+		permBits := fs.FileMode(0777)
+		if runtime.GOOS == "windows" {
+			// Windows has no umask so we must chose a safer set of bits to
+			// begin with.
+			permBits = 0700
+		}
 		fs := f.Filesystem()
-		fd, err := fs.Create(".stfolder")
+		err := fs.Mkdir(".stfolder", permBits)
 		if err != nil {
 			return err
 		}
-		fd.Close()
 		if dir, err := fs.Open("."); err == nil {
 			if serr := dir.Sync(); err != nil {
 				l.Infof("fsync %q failed: %v", ".", serr)

lib/config/testdata/v23.xml

@@ -0,0 +1,16 @@
+<configuration version="22">
+    <folder id="test" path="testdata" type="readonly" ignorePerms="false" rescanIntervalS="600" autoNormalize="true">
+        <filesystemType>basic</filesystemType>
+        <device id="AIR6LPZ-7K4PTTV-UXQSMUU-CPQ5YWH-OEDFIIQ-JUG777G-2YQXXR5-YD6AWQR"></device>
+        <device id="P56IOI7-MZJNU2Y-IQGDREY-DM2MGTI-MGL3BXN-PQ6W5BM-TBBZ4TJ-XZWICQ2"></device>
+        <minDiskFree unit="%">1</minDiskFree>
+        <maxConflicts>-1</maxConflicts>
+        <fsync>true</fsync>
+    </folder>
+    <device id="AIR6LPZ-7K4PTTV-UXQSMUU-CPQ5YWH-OEDFIIQ-JUG777G-2YQXXR5-YD6AWQR" name="node one" compression="metadata">
+        <address>tcp://a</address>
+    </device>
+    <device id="P56IOI7-MZJNU2Y-IQGDREY-DM2MGTI-MGL3BXN-PQ6W5BM-TBBZ4TJ-XZWICQ2" name="node two" compression="metadata">
+        <address>tcp://b</address>
+    </device>
+</configuration>