docs: update CHANGELOG, README keybindings, gitignore ly/

- Automata.Frame() rendered as base layer, form card overlaid via ANSI
  cursor positioning with dark background for readability
- Clock widget showing datetime (Mon Jan 02 15:04:05) in top bar
- Session type label (x11/wayland) shown above switcher selection

.gitignore

@@ -5,4 +5,5 @@ documentation.md
 session.md
 build/*
 examples/*
-things_todo.md
+things_todo.md
+ly/*

CHANGELOG.md

@@ -24,18 +24,34 @@ first public release
 
 ### Recent Fixes
 
+- **DesktopNames parsing** — `.desktop` files now parse the `DesktopNames` field. the first semicolon-delimited entry becomes `XDG_SESSION_DESKTOP`, and the full list with `:` separators becomes `XDG_CURRENT_DESKTOP`. fixes GNOME/KDE sessions not getting proper environment variables
+- **utmpx accounting wired** — `AddUtmpx` and `Close` are now called from `spawnSession` so user logins appear in `who`/`w`/`last`
+- **fixed hardcoded shell** — `Credentials.Shell` now reads from `/etc/passwd` instead of always returning `/bin/sh`. removes duplicate `userShell` logic in exec.go
+- **automata background wired** — `Automata.Frame()` is now rendered in `View()` as the base layer with the login form card overlaid using ANSI cursor positioning. the form has a dark card background for readability
+- **clock widget** — added a datetime display (`Mon Jan 02 15:04:05`) to the top bar, updated every tick
+- **session specifier label** — the environment switcher now shows the session type (`x11`, `wayland`) above the session name, like ly's specifier
+- **form card background** — login content is rendered inside a padded card with a dark background so it reads cleanly over the animated automata
+
 - **utmpx time field portability** — replaced hardcoded `C.__uint32_t` / `C.__int32_t` casts with a C helper function (`auth/utmpx_time.h`) that lets the compiler handle type conversion. fixes build failure on systems where `ut_tv` uses `struct timeval` instead of the 32/64 compat struct
 - **cgo pointer safety for pam** — replaced `unsafe.Pointer(&h)` (Go stack pointer passed to C) with `storeHandle`/`loadHandle` helpers that keep the `cgo.Handle` in C-heap memory. fixes `cgo argument has Go pointer to unpinned Go pointer` panic on Go 1.22+
 - **pam conversation callback** — fixed `unsafe.Slice` using `&r` (pointer-to-pointer) as the backing array instead of `r` (the calloc'd response array), which wrote password bytes into random stack memory. also now only responds to `PAM_PROMPT_ECHO_OFF`/`PAM_PROMPT_ECHO_ON` messages — info and error messages get nil. fixes `pam_unix: auth could not identify password`
+- **cgo handle lifecycle** — moved `cgo.Handle` and its C-heap backing from `Validate` (where they were `defer`-freed on return) into the `Credentials` struct so they stay alive through `OpenSession` and until `CloseSession`. fixes `misuse of an invalid Handle` panic
+- **session spawning** — replaced the broken `ForkExec` (which relaunched the same binary with made-up flags) with a direct `session.Spawn` call that drops privileges and runs the desktop in-process. fixes `flag provided but not defined: -user`
+- **renamed extra/ files** — `lemurs.pam` → `latchd.pam`, `lemurs.service` → `latchd.service`
+- **readme credits** — added a credits section acknowledging lemurs for the `extra/` directory structure and session scanning approach
 - **makefile `enable` and `update` targets** — `make enable` stops any running DM, disables the aliased display-manager, and enables latchd. `make update` runs uninstall → git pull → reinstall in one command
 - **missing `extra/` directory** — added `extra/config.toml`, `extra/xsetup.sh`, `extra/lemurs.pam`, and `extra/lemurs.service` so `make install` can find them
 - **makefile `deps` target** — added `make deps` to automatically install `libpam0g-dev` and `build-essential`, and verify go is present
 - **readme overhaul** — rewrote for clarity: added "what problem does this solve", "how it works", known issues, simpler install instructions, and proper dependency listing
+- **view cleanup** — removed the non-functional automata background overlay from `View()` (the `Frame()` was never called, and the black-space placeholder caused `EEEE` garbage characters on some terminals). also removed a hardcoded 80-char width on the top bar so it adapts to the terminal
+- **session environment setup** — `spawnSession` now calls `SetBasicVariables`, `SetDisplay`, `SetSessionParams`, `SetSeatVars`, `SetSessionVars`, and `SetXDGCommonPaths` before spawning the desktop. fixes `setupX` failing immediately with `missing DISPLAY/XDG_VTNR/HOME env vars` because none were set
+- **pam session error made non-fatal** — `pam_open_session` failure (e.g. `pam_systemd` rejecting the DM process as session leader) is now logged as a warning instead of blocking the entire session spawn. also removed `session include login` from `latchd.pam` since the DM process can't register user sessions with systemd-logind
+- **global session switching with `,` and `.`** — sessions can now be switched from any mode (not just when the switcher is focused). arrows still work when switcher is focused
 
 ### What's Missing
 
 - no tests
-- session spawning uses `ForkExec` which is less clean than the original fork-then-exec model
+- session leader is the latchd process, not the desktop — pam session tracking via systemd-logind may be imperfect
 - not all config options affect the rendering yet
 - occasional terminal state corruption on abrupt exit
-- automata background can flicker on rapid terminal resizes
+- automata background visible at screen edges; form card covers the center

README.md

@@ -65,9 +65,9 @@ pacman -S latchd
 systemctl enable latchd
 ```
 
-## command line
+## Command Line
 
-```
+```bash
 latchd [options]
 
   -c, --config <file>     config path (default: /etc/latchd/config.toml)
@@ -82,9 +82,9 @@ latchd [options]
   --initial-path <path>   override initial PATH value
 ```
 
-## adding sessions
+## Adding Sessions
 
-drop executable scripts into the right folder and they show up in the switcher.
+Drop executable scripts into the right folder and they show up in the switcher.
 
 **x11** — put your xinitrc scripts in `/etc/latchd/wms/`:
 
@@ -113,7 +113,7 @@ tty sessions are added automatically if no other environments are found, or you
 
 ## configuring
 
-the config lives at `/etc/latchd/config.toml`. all options are documented inline in the file. you can also use a `variables.toml` file with `$VAR` syntax:
+The config lives at `/etc/latchd/config.toml`. all options are documented inline in the file. you can also use a `variables.toml` file with `$VAR` syntax:
 
 ```toml
 # /etc/latchd/variables.toml
@@ -127,7 +127,7 @@ title_color_focused = "$accent"
 border_color_focused = "$accent"
 ```
 
-## debugging
+## Debugging
 
 three log files:
 
@@ -137,7 +137,7 @@ three log files:
 
 run `latchd --show-config` to verify your configuration. run `latchd --preview` to test the login screen without leaving your current session.
 
-## keybindings
+## Keybindings
 
 standard shell-style bindings in text fields:
 
@@ -151,13 +151,15 @@ standard shell-style bindings in text fields:
 | ctrl+b/f | left/right |
 | ctrl+p/n | up/down (previous/next field) |
 | tab, shift+tab | next/prev field |
-| left/right | switch session (in switcher mode) |
+| down / up | next/prev field |
+| left/right | previous/next session (switcher mode) |
+| , / . | previous/next session (any mode) |
 | f1, f2 | power controls |
 | ctrl+u | admin unlock (when account is locked) |
 
 ## source layout
 
-```
+```bash
 src/
 ├── main.go           entry point, cli, vt switching, session forking
 ├── auth/
@@ -182,3 +184,7 @@ src/
 ## license
 
 MIT or Apache-2.0
+
+## credits
+
+the `extra/` directory structure and the session scanning / pam delegation approach are adapted from [lemurs](https://github.com/coastalwhite/lemurs), a rust display manager.

extra/latchd.pam

@@ -1,5 +1,4 @@
 #%PAM-1.0
 auth        include    login
 account     include    login
-session     include    login
 password    include    login

src/auth/pam.go

@@ -37,9 +37,11 @@ static struct pam_conv makePAMConv(void *data) {
 import "C"
 import (
 	"fmt"
+	"os"
 	ouser "os/user"
 	"runtime"
 	"runtime/cgo"
+	"strings"
 	"unsafe"
 )
 
@@ -67,6 +69,8 @@ type Credentials struct {
 	HomeDir    string
 	Shell      string
 	pamHandle  *C.pam_handle_t
+	pamData    unsafe.Pointer
+	pamCB      cgo.Handle
 }
 
 //export latchd_pam_conv
@@ -110,16 +114,16 @@ func Validate(user, pass, service string) (*Credentials, error) {
 	defer C.free(unsafe.Pointer(cUser))
 
 	h := cgo.NewHandle(pass)
-	defer h.Delete()
 
 	cData := C.storeHandle(C.uintptr_t(h))
-	defer C.free(cData)
 
 	conv := C.makePAMConv(cData)
 
 	var pamh *C.pam_handle_t
 	ret := C.pam_start(cSvc, cUser, &conv, &pamh)
 	if ret != C.PAM_SUCCESS {
+		h.Delete()
+		C.free(cData)
 		return nil, &AuthError{ErrPAMService, fmt.Sprintf("pam_start: %s", pamErr(pamh, ret))}
 	}
 
@@ -127,6 +131,8 @@ func Validate(user, pass, service string) (*Credentials, error) {
 	if ret != C.PAM_SUCCESS {
 		msg := fmt.Sprintf("auth failed: %s", pamErr(pamh, ret))
 		C.pam_end(pamh, ret)
+		h.Delete()
+		C.free(cData)
 		return nil, &AuthError{ErrAccountValidation, msg}
 	}
 
@@ -134,12 +140,16 @@ func Validate(user, pass, service string) (*Credentials, error) {
 	if ret != C.PAM_SUCCESS {
 		msg := fmt.Sprintf("account: %s", pamErr(pamh, ret))
 		C.pam_end(pamh, ret)
+		h.Delete()
+		C.free(cData)
 		return nil, &AuthError{ErrAccountValidation, msg}
 	}
 
 	u, err := ouser.Lookup(user)
 	if err != nil {
 		C.pam_end(pamh, ret)
+		h.Delete()
+		C.free(cData)
 		return nil, &AuthError{ErrUsernameNotFound, fmt.Sprintf("lookup %s: %v", user, err)}
 	}
 
@@ -161,8 +171,10 @@ func Validate(user, pass, service string) (*Credentials, error) {
 		PrimaryGID: gid,
 		AllGIDs:    gids,
 		HomeDir:    u.HomeDir,
-		Shell:      "/bin/sh",
+		Shell:      shellFromPasswd(uid),
 		pamHandle:  pamh,
+		pamData:    cData,
+		pamCB:      h,
 	}, nil
 }
 
@@ -180,6 +192,11 @@ func (c *Credentials) CloseSession() {
 		C.pam_end(c.pamHandle, 0)
 		c.pamHandle = nil
 	}
+	if c.pamData != nil {
+		C.free(c.pamData)
+		c.pamData = nil
+	}
+	c.pamCB.Delete()
 }
 
 func pamErr(h *C.pam_handle_t, e C.int) string {
@@ -196,3 +213,21 @@ func atou32(s string) uint32 {
 	}
 	return n
 }
+
+func shellFromPasswd(uid uint32) string {
+	data, err := os.ReadFile("/etc/passwd")
+	if err != nil {
+		return "/bin/sh"
+	}
+	uidStr := fmt.Sprint(uid)
+	for _, line := range strings.Split(string(data), "\n") {
+		parts := strings.Split(line, ":")
+		if len(parts) >= 7 && parts[2] == uidStr && parts[6] != "" {
+			sh := parts[6]
+			if sh != "/sbin/nologin" && sh != "/usr/sbin/nologin" && sh != "/bin/false" {
+				return sh
+			}
+		}
+	}
+	return "/bin/sh"
+}

src/login/login.go

@@ -270,6 +270,25 @@ func (m *Model) handleKey(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
 		return m, nil
 	}
 
+	if len(m.envs) > 0 {
+		switch k {
+		case ",", "<":
+			m.selIdx--
+			if m.selIdx < 0 {
+				m.selIdx = len(m.envs) - 1
+			}
+			m.spring = -4
+			return m, nil
+		case ".", ">":
+			m.selIdx++
+			if m.selIdx >= len(m.envs) {
+				m.selIdx = 0
+			}
+			m.spring = 4
+			return m, nil
+		}
+	}
+
 	switch m.mode {
 	case modeSwitcher:
 		switch k {
@@ -419,6 +438,9 @@ var (
 	infoCol  = lipgloss.Color("3")   // yellow
 	greenCol = lipgloss.Color("2")   // green
 
+	cardBg   = lipgloss.Color("0")   // black card background
+	cardPad  = 2
+
 	avatarStyle = lipgloss.NewStyle().Foreground(accent)
 
 	fieldBox = lipgloss.NewStyle().
@@ -461,28 +483,65 @@ func (m *Model) View() string {
 
 	content := m.renderLayout()
 
-	if m.automata != nil && m.width > 0 && m.height > 0 {
+	if m.width > 0 && m.height > 0 {
+		if m.automata != nil {
+			bg := m.automata.Frame()
+			var sb strings.Builder
+			sb.WriteString(bg)
+			sb.WriteString("\x1b[H") // cursor home before overlaying
+			sb.WriteString(overlayCenter(m.width, m.height, content))
+			return sb.String()
+		}
 		return lipgloss.Place(m.width, m.height, lipgloss.Center, lipgloss.Center,
 			content,
-			lipgloss.WithWhitespaceChars(" "),
-			lipgloss.WithWhitespaceForeground(lipgloss.Color("0")),
 		)
 	}
 	return content
 }
 
+func overlayCenter(w, h int, content string) string {
+	lines := strings.Split(content, "\n")
+	cw := 0
+	for _, l := range lines {
+		if lw := lipgloss.Width(l); lw > cw {
+			cw = lw
+		}
+	}
+	cx := (w - cw) / 2
+	cy := (h - len(lines)) / 2
+	if cx < 0 {
+		cx = 0
+	}
+	if cy < 0 {
+		cy = 0
+	}
+
+	var sb strings.Builder
+	for i, line := range lines {
+		sb.WriteString(fmt.Sprintf("\x1b[%d;%dH", cy+i+1, cx+1))
+		sb.WriteString(line)
+	}
+	return sb.String()
+}
+
 func (m *Model) renderLayout() string {
-	// top bar: power hints
-	top := m.renderPowerHints()
-	top = lipgloss.NewStyle().Width(80).Align(lipgloss.Left).Render(top)
+	clock := m.renderClock()
+
+	// top bar: power hints on left, clock on right
+	var topParts []string
+	topParts = append(topParts, m.renderPowerHints())
+	if clock != "" {
+		topParts = append(topParts, clock)
+	}
+	top := strings.Join(topParts, "   ")
 
 	// avatar + form side by side
 	avatar := m.renderAvatar()
 	form := m.renderForm()
 	mid := lipgloss.JoinHorizontal(lipgloss.Top, avatar, "   ", form)
 
-	// DE switcher below
-	sw := m.renderSwitcherDots()
+	// DE switcher with specifier label
+	sw := m.renderSwitcher()
 
 	// caps lock
 	caps := m.renderCapsLock()
@@ -520,7 +579,10 @@ func (m *Model) renderLayout() string {
 			joined = pad + joined
 		}
 	}
-	return joined
+	return lipgloss.NewStyle().
+		Background(cardBg).
+		Padding(cardPad, cardPad+2).
+		Render(joined)
 }
 
 func (m *Model) renderPowerHints() string {
@@ -578,7 +640,12 @@ func (m *Model) renderForm() string {
 	return lipgloss.JoinVertical(lipgloss.Left, userField, "", passField)
 }
 
-func (m *Model) renderSwitcherDots() string {
+func (m *Model) renderClock() string {
+	now := time.Now()
+	return powerHint.Render(now.Format("Mon Jan 02 15:04:05"))
+}
+
+func (m *Model) renderSwitcher() string {
 	if len(m.envs) == 0 {
 		return swNeighbour.Align(lipgloss.Center).Render("no desktop environments found")
 	}
@@ -588,6 +655,9 @@ func (m *Model) renderSwitcherDots() string {
 
 	var parts []string
 
+	// session specifier (like "x11", "wayland")
+	spec := swDot.Render(m.envs[m.selIdx].Kind + "  ")
+
 	if cfg.ShowMovers && m.selIdx > 0 {
 		parts = append(parts, swMover.Render(cfg.LeftMover+" "))
 	}
@@ -620,7 +690,7 @@ func (m *Model) renderSwitcherDots() string {
 	}
 	dotLine := strings.Join(dots, " ")
 
-	return lipgloss.JoinVertical(lipgloss.Center, swLine, dotLine)
+	return lipgloss.JoinVertical(lipgloss.Center, spec, swLine, dotLine)
 }
 
 func (m *Model) renderCapsLock() string {

src/main.go

@@ -19,6 +19,7 @@ import (
 	"latchd/auth"
 	"latchd/config"
 	"latchd/login"
+	"latchd/session"
 	"latchd/tui/bg"
 )
 
@@ -144,39 +145,41 @@ func spawnSession(res *login.Result) error {
 		return nil
 	}
 	log.Printf("spawning %s → %s (%s)", res.Username, res.Env.Title, res.Env.Kind)
+
 	creds, err := auth.Validate(res.Username, res.Password, res.Config.PAMService)
 	if err != nil {
 		return fmt.Errorf("auth: %w", err)
 	}
 	defer creds.CloseSession()
 
-	pid, err := syscall.ForkExec("/proc/self/exe", []string{
-		"latchd-session",
-		"--user", creds.Username,
-		"--uid", fmt.Sprintf("%d", creds.UID),
-		"--gid", fmt.Sprintf("%d", creds.PrimaryGID),
-		"--home", creds.HomeDir,
-		"--shell", creds.Shell,
-		"--env-kind", res.Env.Kind,
-		"--env-exec", res.Env.XinitrcPath,
-		"--tty", fmt.Sprintf("%d", res.Config.TTY),
-	}, &syscall.ProcAttr{
-		Env:   os.Environ(),
-		Dir:   creds.HomeDir,
-		Files: []uintptr{0, 1, 2},
-		Sys:   &syscall.SysProcAttr{Setsid: true},
-	})
+	if err := creds.OpenSession(); err != nil {
+		log.Printf("pam session warning: %v", err)
+	}
+
+	session.SetBasicVariables(creds.Username, creds.HomeDir, creds.Shell, res.Config.InitialPath)
+	if res.Env.Kind == "x11" {
+		session.SetDisplay(res.Config.X11.Display)
+	}
+	session.RemoveXDG()
+	session.SetSessionParams(res.Env.Kind)
+	session.SetSeatVars(res.Config.TTY)
+	session.SetSessionVars(creds.UID)
+	session.SetXDGCommonPaths(creds.HomeDir)
+	session.SetDesktopVars(res.Env.DesktopNames, res.Env.SessionDesktop)
+
+	sess, err := session.Spawn(&res.Env, creds.UID, creds.PrimaryGID, creds.AllGIDs, &res.Config)
 	if err != nil {
-		return fmt.Errorf("fork: %w", err)
+		return fmt.Errorf("spawn: %w", err)
 	}
 
-	creds.OpenSession()
+	utmpx := auth.AddUtmpx(creds.Username, res.Config.TTY, uint32(sess.PID()))
+	defer utmpx.Close()
 
-	var ws syscall.WaitStatus
-	if _, err := syscall.Wait4(pid, &ws, 0, nil); err != nil {
-		return fmt.Errorf("wait: %w", err)
+	err = sess.Wait()
+	if err != nil {
+		log.Printf("session exited: %v", err)
 	}
-	log.Printf("session pid %d exited %d", pid, ws.ExitStatus())
+	log.Printf("session pid %d ended", sess.PID())
 	return nil
 }
 

src/session/env.go

@@ -57,6 +57,15 @@ func SetXDGCommonPaths(home string) {
 	setOrOwn("XDG_CONFIG_DIRS", "/etc/xdg")
 }
 
+func SetDesktopVars(currentDesktop, sessionDesktop string) {
+	if currentDesktop != "" {
+		setOrOwn("XDG_CURRENT_DESKTOP", currentDesktop)
+	}
+	if sessionDesktop != "" {
+		setOrOwn("XDG_SESSION_DESKTOP", sessionDesktop)
+	}
+}
+
 func setOrOwn(k, v string) {
 	if _, ok := os.LookupEnv(k); !ok {
 		os.Setenv(k, v)

src/session/exec.go

@@ -16,10 +16,12 @@ import (
 )
 
 type PostLoginEnv struct {
-	Kind        string // "x11", "wayland", "tty"
-	Title       string
-	XinitrcPath string
-	ScriptPath  string
+	Kind             string // "x11", "wayland", "tty"
+	Title            string
+	XinitrcPath      string
+	ScriptPath       string
+	DesktopNames     string // for XDG_CURRENT_DESKTOP (colon-separated)
+	SessionDesktop   string // for XDG_SESSION_DESKTOP
 }
 
 type SpawnedEnv struct {

src/session/scan.go

@@ -13,10 +13,11 @@ import (
 )
 
 type DesktopEntry struct {
-	Name      string
-	Exec      string
-	Hidden    bool
-	NoDisplay bool
+	Name         string
+	Exec         string
+	DesktopNames string
+	Hidden       bool
+	NoDisplay    bool
 }
 
 func parseDesktopEntry(path string) (*DesktopEntry, error) {
@@ -51,6 +52,8 @@ func parseDesktopEntry(path string) (*DesktopEntry, error) {
 			e.Name = v
 		case "Exec":
 			e.Exec = v
+		case "DesktopNames":
+			e.DesktopNames = v
 		case "Hidden":
 			e.Hidden = strings.EqualFold(v, "true")
 		case "NoDisplay":
@@ -97,15 +100,28 @@ func scanDesktopDir(dir, kind string, envs *[]PostLoginEnv) {
 		if err != nil || de.Hidden || de.NoDisplay {
 			continue
 		}
+		desktopNames, sessionDesktop := splitDesktopNames(de.DesktopNames, e.Name())
 		*envs = append(*envs, PostLoginEnv{
-			Kind:        kind,
-			Title:       de.Name,
-			XinitrcPath: de.Exec,
-			ScriptPath:  de.Exec,
+			Kind:           kind,
+			Title:          de.Name,
+			XinitrcPath:    de.Exec,
+			ScriptPath:     de.Exec,
+			DesktopNames:   desktopNames,
+			SessionDesktop: sessionDesktop,
 		})
 	}
 }
 
+func splitDesktopNames(raw, fallback string) (currentDesktop, sessionDesktop string) {
+	if raw == "" {
+		return fallback, fallback
+	}
+	parts := strings.SplitN(raw, ";", 2)
+	sessionDesktop = strings.TrimSpace(parts[0])
+	currentDesktop = strings.ReplaceAll(raw, ";", ":")
+	return
+}
+
 func scanScriptDir(dir, kind string, envs *[]PostLoginEnv) {
 	entries, err := os.ReadDir(dir)
 	if err != nil {