feat: add -l (list) and -u (unmount) flags

A second sshfsc <alias> call only printed "Already mounted"; tearing
down a mount required ls + fusermount by hand. -l lists active mounts
verified via mountinfo.Mounted, -u <Host> unmounts and removes the
empty mountpoint dir. Flags are mutually exclusive.

main.go

@@ -4,8 +4,11 @@
 package main
 
 import (
+	"errors"
 	"flag"
 	"fmt"
+	"io"
+	"io/fs"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -26,6 +29,8 @@ var (
 var (
 	eFlag = flag.Bool("e", false, "open mountpoint in your editor")
 	vFlag = flag.Bool("v", false, "verbose: print resolved ssh_config fields")
+	lFlag = flag.Bool("l", false, "list active mounts and exit")
+	uFlag = flag.Bool("u", false, "unmount the given <Host> and exit")
 	rDir  string
 )
 
@@ -38,13 +43,39 @@ func main() {
 	flag.Usage = func() {
 		fmt.Fprintf(os.Stderr,
 			"usage: sshfsc [flags] <Host>\n\n"+
-				"Mount a remote home directory via sshfs based on ~/.ssh/config entries.\n\n"+
+				"Mount a remote home directory via sshfs based on ~/.ssh/config entries.\n"+
+				"Use -l to list active mounts; -u <Host> to unmount.\n\n"+
 				"Flags:\n")
 		flag.PrintDefaults()
 	}
 	flag.Parse()
 	args := flag.Args()
 
+	if *lFlag && *uFlag {
+		fmt.Fprintln(os.Stderr, "-l and -u are mutually exclusive")
+		os.Exit(2)
+	}
+
+	if *lFlag {
+		if err := list_mounts(os.Stdout); err != nil {
+			fmt.Fprintln(os.Stderr, "list_mounts() failed:", err)
+			os.Exit(8)
+		}
+		return
+	}
+
+	if *uFlag {
+		if len(args) == 0 {
+			fmt.Fprintln(os.Stderr, "-u requires <Host> argument")
+			os.Exit(2)
+		}
+		if err := unmount_sshfs(args[0]); err != nil {
+			fmt.Fprintln(os.Stderr, "unmount_sshfs() failed:", err)
+			os.Exit(9)
+		}
+		return
+	}
+
 	if len(args) == 0 {
 		fmt.Fprintln(os.Stderr, "No hostname specified.")
 		os.Exit(2)
@@ -182,32 +213,118 @@ func run_editor(mount string) error {
 	return cmd.Start()
 }
 
-func verify_mount_dir(name string) (string, error) {
+// mount_base resolves the per-user sshfs mount base under $XDG_RUNTIME_DIR.
+// When create is true, the base directory is mkdir'd; otherwise a missing
+// base bubbles up as fs.ErrNotExist so callers can decide how to react.
+func mount_base(create bool) (string, error) {
 	runtime := os.Getenv("XDG_RUNTIME_DIR")
 	if runtime == "" {
 		runtime = filepath.Join("/run/user", strconv.Itoa(os.Getuid()))
 	}
 	base := filepath.Join(runtime, "sshfs")
-	if err := os.MkdirAll(base, 0700); err != nil {
-		return "", fmt.Errorf("create base %q: %w", base, err)
+	if create {
+		if err := os.MkdirAll(base, 0700); err != nil {
+			return "", fmt.Errorf("create base %q: %w", base, err)
+		}
+	} else if _, err := os.Stat(base); err != nil {
+		return "", err
 	}
 	realBase, err := filepath.EvalSymlinks(base)
 	if err != nil {
 		return "", fmt.Errorf("resolve base %q: %w", base, err)
 	}
-	mount := filepath.Clean(filepath.Join(realBase, name))
-	if !strings.HasPrefix(mount, realBase+string(os.PathSeparator)) {
-		return "", fmt.Errorf("name %q escapes mount base %q", name, realBase)
+	return realBase, nil
+}
+
+// mount_path joins base + name with traversal and symlink guards.
+// It does not create the mountpoint directory.
+func mount_path(base, name string) (string, error) {
+	mount := filepath.Clean(filepath.Join(base, name))
+	if !strings.HasPrefix(mount, base+string(os.PathSeparator)) {
+		return "", fmt.Errorf("name %q escapes mount base %q", name, base)
 	}
 	if info, err := os.Lstat(mount); err == nil && info.Mode()&os.ModeSymlink != 0 {
 		return "", fmt.Errorf("mount path %q is a symlink", mount)
 	}
+	return mount, nil
+}
+
+func verify_mount_dir(name string) (string, error) {
+	base, err := mount_base(true)
+	if err != nil {
+		return "", err
+	}
+	mount, err := mount_path(base, name)
+	if err != nil {
+		return "", err
+	}
 	if err := os.MkdirAll(mount, 0700); err != nil {
 		return "", fmt.Errorf("create mount dir %q: %w", mount, err)
 	}
 	return mount, nil
 }
 
+func list_mounts(out io.Writer) error {
+	base, err := mount_base(false)
+	if err != nil {
+		if errors.Is(err, fs.ErrNotExist) {
+			return nil
+		}
+		return err
+	}
+	entries, err := os.ReadDir(base)
+	if err != nil {
+		return fmt.Errorf("read base %q: %w", base, err)
+	}
+	for _, entry := range entries {
+		if !entry.IsDir() {
+			continue
+		}
+		path := filepath.Join(base, entry.Name())
+		ok, merr := mountinfo.Mounted(path)
+		if merr != nil || !ok {
+			continue
+		}
+		fmt.Fprintln(out, entry.Name())
+	}
+	return nil
+}
+
+func unmount_sshfs(alias string) error {
+	if err := validate_ssh_field("alias", alias, rxHostUser); err != nil {
+		return err
+	}
+	base, err := mount_base(false)
+	if err != nil {
+		if errors.Is(err, fs.ErrNotExist) {
+			return fmt.Errorf("not mounted: %s", alias)
+		}
+		return err
+	}
+	mount, err := mount_path(base, alias)
+	if err != nil {
+		return err
+	}
+	ok, err := mountinfo.Mounted(mount)
+	if err != nil {
+		return fmt.Errorf("mountinfo.Mounted(%q): %w", mount, err)
+	}
+	if !ok {
+		return fmt.Errorf("not mounted: %s", alias)
+	}
+	cmd := exec.Command("fusermount", "-u", mount)
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	if err := cmd.Run(); err != nil {
+		return fmt.Errorf("fusermount -u %q: %w", mount, err)
+	}
+	if err := os.Remove(mount); err != nil {
+		fmt.Fprintf(os.Stderr, "warning: remove empty mount dir %q: %v\n", mount, err)
+	}
+	fmt.Println("Unmounted:", alias)
+	return nil
+}
+
 func mount_sshfs(alias string, user string, ifile string, port string, mount string, remoteDir string) error {
 	cmd := exec.Command("sshfs", "-p", port,
 		"-o", "IdentityFile="+ifile,