Add support for custom mount options (#25)

Author: AlexSSD7

cmd/run.go

@@ -80,13 +80,18 @@ var runCmd = &cobra.Command{
 				fsToLog = fsTypeOverride
 			}
 
-			slog.Info("Mounting the device", "dev", vmMountDevName, "fs", fsToLog, "luks", luksFlag)
+			mountOptionsToLog := "<default>"
+			if mountOptionsFlag != "" {
+				mountOptionsToLog = mountOptionsFlag
+			}
 
-			err := fm.Mount(vmMountDevName, vm.MountOptions{
-				LUKSContainerPreopen: vmRuntimeLUKSContainerDevice,
+			slog.Info("Mounting the device", "dev", vmMountDevName, "fs", fsToLog, "luks", luksFlag, "mountoptions", mountOptionsToLog)
 
-				FSTypeOverride: fsTypeOverride,
-				LUKS:           luksFlag,
+			err := fm.Mount(vmMountDevName, vm.MountConfig{
+				LUKSContainerPreopen: vmRuntimeLUKSContainerDevice,
+				FSTypeOverride:       fsTypeOverride,
+				LUKS:                 luksFlag,
+				MountOptions:         mountOptionsFlag,
 			})
 			if err != nil {
 				slog.Error("Failed to mount the disk inside the VM", "error", err.Error())
@@ -143,6 +148,7 @@ var (
 	shareBackendFlag     string
 	smbUseExternAddrFlag bool
 	debugShellFlag       bool
+	mountOptionsFlag     string
 )
 
 func init() {
@@ -163,5 +169,6 @@ func init() {
 	runCmd.Flags().StringVar(&shareListenIPFlag, "share-listen", share.GetDefaultListenIPStr(), "Specifies the IP to bind the network share port to. NOTE: For FTP, changing the bind address is not enough to connect remotely. You should also specify --ftp-extip.")
 
 	runCmd.Flags().StringVar(&ftpExtIPFlag, "ftp-extip", share.GetDefaultListenIPStr(), "Specifies the external IP the FTP server should advertise.")
-	runCmd.Flags().BoolVar(&smbUseExternAddrFlag, "smb-extern", share.IsSMBExtModeDefault(), "Specifies whether Linsk emulate external networking for the VM's SMB server. This is the default for Windows as there is no way to specify ports in Windows SMB client.")
+	runCmd.Flags().BoolVar(&smbUseExternAddrFlag, "smb-extern", share.IsSMBExtModeDefault(), "Specifies whether Linsk should emulate external networking for the VM's SMB server. This is the default for Windows as there is no way to specify ports in Windows SMB client.")
+	runCmd.Flags().StringVar(&mountOptionsFlag, "mount-options", "", "Specifies the mount options to be passed to the -o flag of the mount.")
 }

utils/validations.go

@@ -37,10 +37,16 @@ func ClearUnprintableChars(s string, allowNewlines bool) string {
 	}, s)
 }
 
-var fsTypeRegex = regexp.MustCompile(`^[a-z0-9]+$`)
+var fsTypeRegexp = regexp.MustCompile(`^[a-z0-9]+$`)
 
 func ValidateFsType(s string) bool {
-	return fsTypeRegex.MatchString(s)
+	return fsTypeRegexp.MatchString(s)
+}
+
+var mountOptionsRegexp = regexp.MustCompile(`^([a-zA-Z0-9_]+(=[a-zA-Z0-9]+)?)(,[a-zA-Z0-9_]+(=[a-zA-Z0-9]+)?)*$`)
+
+func ValidateMountOptions(s string) bool {
+	return mountOptionsRegexp.MatchString(s)
 }
 
 var devNameRegexp = regexp.MustCompile(`^[0-9A-Za-z_-]+$`)

vm/filemanager.go

@@ -82,11 +82,12 @@ func (fm *FileManager) Lsblk() ([]byte, error) {
 	return ret, nil
 }
 
-type MountOptions struct {
+type MountConfig struct {
 	LUKSContainerPreopen string
 
 	FSTypeOverride string
 	LUKS           bool
+	MountOptions   string
 }
 
 func (fm *FileManager) luksOpen(sc *ssh.Client, fullDevPath string, luksDMName string) error {
@@ -202,7 +203,7 @@ func (fm *FileManager) preopenLUKSContainerWithSSH(sc *ssh.Client, containerDevP
 	return nil
 }
 
-func (fm *FileManager) Mount(devName string, mo MountOptions) error {
+func (fm *FileManager) Mount(devName string, mc MountConfig) error {
 	if devName == "" {
 		return fmt.Errorf("device name is empty")
 	}
@@ -220,13 +221,19 @@ func (fm *FileManager) Mount(devName string, mo MountOptions) error {
 	fullDevPath := "/dev/" + devName
 
 	var fsOverride string
-
-	if mo.FSTypeOverride != "" {
-		if !utils.ValidateFsType(mo.FSTypeOverride) {
+	if mc.FSTypeOverride != "" {
+		if !utils.ValidateFsType(mc.FSTypeOverride) {
 			return fmt.Errorf("bad fs type override (contains illegal characters)")
 		}
+		fsOverride = mc.FSTypeOverride
+	}
 
-		fsOverride = mo.FSTypeOverride
+	var mountOptions string
+	if mc.MountOptions != "" {
+		if !utils.ValidateMountOptions(mc.MountOptions) {
+			return fmt.Errorf("invalid mount options (contains illegal characters)")
+		}
+		mountOptions = mc.MountOptions
 	}
 
 	sc, err := fm.vm.DialSSH()
@@ -236,14 +243,14 @@ func (fm *FileManager) Mount(devName string, mo MountOptions) error {
 
 	defer func() { _ = sc.Close() }()
 
-	if mo.LUKSContainerPreopen != "" {
-		err := fm.preopenLUKSContainerWithSSH(sc, mo.LUKSContainerPreopen)
+	if mc.LUKSContainerPreopen != "" {
+		err := fm.preopenLUKSContainerWithSSH(sc, mc.LUKSContainerPreopen)
 		if err != nil {
 			return errors.Wrap(err, "preopen luks container")
 		}
 	}
 
-	if mo.LUKS {
+	if mc.LUKS {
 		luksDMName := "cryptmnt"
 
 		err = fm.luksOpen(sc, fullDevPath, luksDMName)
@@ -258,6 +265,9 @@ func (fm *FileManager) Mount(devName string, mo MountOptions) error {
 	if fsOverride != "" {
 		cmd += "-t " + shellescape.Quote(fsOverride) + " "
 	}
+	if mountOptions != "" {
+		cmd += "-o " + shellescape.Quote(mountOptions) + " "
+	}
 	cmd += shellescape.Quote(fullDevPath) + " /mnt"
 
 	_, err = sshutil.RunSSHCmd(fm.vm.ctx, sc, cmd)