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.

DECISIONS.md

@@ -1,5 +1,48 @@
 # Decisions
 
+## 2026-05-04 – Add `-l` (list) and `-u` (unmount) flags
+- **Who**: Dom, ClaudeCode
+- **Why**: Mounts under `$XDG_RUNTIME_DIR/sshfs/<alias>` had to be listed and
+  torn down with `ls` and `fusermount -u` by hand. A second `sshfsc <alias>`
+  call only prints `!!! Already mounted` and exits, so the tool gave no first-
+  class way to undo what it set up. `-l` and `-u` close that gap without
+  changing the default mount flow.
+- **Tradeoffs**:
+  - Flag-based UX over subcommands keeps the existing `-e`/`-v`/`-r` style.
+    `-l` and `-u` are mutually exclusive (exit 2 when both passed). `-u` reuses
+    the positional `<Host>` argument; no separate value flag needed.
+  - `-l` only lists *real* mounts (verified via `mountinfo.Mounted`). Stale
+    empty dirs left behind by failed mounts are silently filtered, not
+    surfaced — keeps the output a true list of teardownable targets. Cleanup
+    of stale dirs is not implemented; tmpfs reclaims them on logout.
+  - `-u` shells out to `fusermount -u` and best-effort `os.Remove`s the empty
+    mount dir afterwards. A failed `Remove` warns but does not fail the
+    command — the unmount itself already succeeded.
+  - `mount_base(create bool)` returns `fs.ErrNotExist` when `create=false` and
+    the base is missing. `list_mounts` swallows that into "no mounts";
+    `unmount_sshfs` translates it into `not mounted: <alias>` so the caller
+    sees a single coherent error regardless of whether the alias-dir, the
+    base, or `XDG_RUNTIME_DIR` was missing.
+- **How**:
+  - `verify_mount_dir` split into `mount_base(create bool)` (XDG resolve +
+    optional mkdir + EvalSymlinks) and `mount_path(base, name)` (join +
+    traversal + symlink guard, no mkdir). The original `verify_mount_dir`
+    becomes a thin wrapper that composes both and creates the mountpoint —
+    only the mount path needs that mkdir.
+  - `list_mounts(io.Writer)` reads the base dir, runs `mountinfo.Mounted` per
+    entry, prints alias names that pass. Takes a writer so tests can capture
+    output without stdout redirection.
+  - `unmount_sshfs(alias)` validates against `rxHostUser`, resolves the
+    mountpoint, checks `mountinfo.Mounted`, then `exec.Command("fusermount",
+    "-u", mount).Run()` and `os.Remove(mount)`.
+  - `main()` flow: after `flag.Parse()`, branch on `*lFlag` / `*uFlag` before
+    the existing mount path. Mutex check up front. Exit codes 8 (list) and 9
+    (unmount) extend the existing 2..7 range.
+  - Tests: `TestListMountsMissingBase`, `TestListMountsFiltersUnmounted`,
+    `TestUnmountRejectsBadAlias`, `TestUnmountNotMountedMissingBase`,
+    `TestUnmountNotMountedExistingDir`. The real `fusermount` path is not
+    exercised in unit tests — the not-mounted check returns before the exec.
+
 ## 2026-04-28 – Move mount base from `~/Servers/` to `$XDG_RUNTIME_DIR/sshfs/`
 - **Who**: Dom, ClaudeCode
 - **Why**: `~/Servers/` is non-standard. XDG Base Directory spec defines

README.md

@@ -27,7 +27,9 @@ install -Dm755 sshfsc /usr/local/bin/sshfsc
 # Usage
 
 ```
-sshfsc <Host>
+sshfsc <Host>          # mount
+sshfsc -u <Host>       # unmount
+sshfsc -l              # list active mounts
 ```
 
 ## Arguments
@@ -37,6 +39,8 @@ sshfsc <Host>
 | `-e` | open mountpoint in your editor |
 | `-v` | verbose: print resolved ssh_config fields (HostName, User, Port, IdentityFile) |
 | `-r`, `--remote-dir <path>` | remote directory to mount (default: remote home) |
+| `-l` | list active mounts under `$XDG_RUNTIME_DIR/sshfs/` and exit |
+| `-u` | unmount the given `<Host>` and exit (mutually exclusive with `-l`) |
 
 By default only the resolved mount path is printed. Use `-v` for the full
 ssh_config dump.

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 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,

main_test.go

@@ -4,6 +4,7 @@
 package main
 
 import (
+	"bytes"
 	"os"
 	"path/filepath"
 	"strings"
@@ -138,3 +139,64 @@ func TestVerifyMountDirRejectsSymlink(t *testing.T) {
 		t.Fatalf("want symlink rejection, got %v", err)
 	}
 }
+
+func TestListMountsMissingBase(t *testing.T) {
+	runtime := t.TempDir()
+	t.Setenv("XDG_RUNTIME_DIR", runtime)
+	var buf bytes.Buffer
+	if err := list_mounts(&buf); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if buf.Len() != 0 {
+		t.Fatalf("want empty output, got %q", buf.String())
+	}
+}
+
+func TestListMountsFiltersUnmounted(t *testing.T) {
+	runtime := t.TempDir()
+	t.Setenv("XDG_RUNTIME_DIR", runtime)
+	base := filepath.Join(runtime, "sshfs")
+	for _, name := range []string{"stale1", "stale2"} {
+		if err := os.MkdirAll(filepath.Join(base, name), 0700); err != nil {
+			t.Fatalf("setup stale dir: %v", err)
+		}
+	}
+	var buf bytes.Buffer
+	if err := list_mounts(&buf); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if buf.Len() != 0 {
+		t.Fatalf("want stale dirs filtered, got %q", buf.String())
+	}
+}
+
+func TestUnmountRejectsBadAlias(t *testing.T) {
+	runtime := t.TempDir()
+	t.Setenv("XDG_RUNTIME_DIR", runtime)
+	err := unmount_sshfs("../etc")
+	if err == nil || !strings.Contains(err.Error(), "disallowed characters") {
+		t.Fatalf("want validation error, got %v", err)
+	}
+}
+
+func TestUnmountNotMountedMissingBase(t *testing.T) {
+	runtime := t.TempDir()
+	t.Setenv("XDG_RUNTIME_DIR", runtime)
+	err := unmount_sshfs("myhost")
+	if err == nil || !strings.Contains(err.Error(), "not mounted") {
+		t.Fatalf("want not-mounted error, got %v", err)
+	}
+}
+
+func TestUnmountNotMountedExistingDir(t *testing.T) {
+	runtime := t.TempDir()
+	t.Setenv("XDG_RUNTIME_DIR", runtime)
+	base := filepath.Join(runtime, "sshfs")
+	if err := os.MkdirAll(filepath.Join(base, "myhost"), 0700); err != nil {
+		t.Fatalf("setup mount dir: %v", err)
+	}
+	err := unmount_sshfs("myhost")
+	if err == nil || !strings.Contains(err.Error(), "not mounted") {
+		t.Fatalf("want not-mounted error, got %v", err)
+	}
+}