> ## Documentation Index
> Fetch the complete documentation index at: https://docs.otter-shell.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Greeter and auth

> PAM, session catalog, logind, and power actions in otter-desktop.

## PAM

```zig theme={null}
var auth = otter_desktop.PamAuth.init("otter-lock");
const result = try auth.authenticate(password);
```

`PamSession` wraps full session open/close for `otter-greeter`. Build with `-Denable_pam=true` for lock and greeter packages.

## Session catalog

`session_catalog` scans Wayland `.desktop` session files and maps `DesktopNames` to XDG session environment variables.

`session_launcher` builds user/session env without inventing logind-owned variables.

## Accounts and seats

* `accounts_service`: user list with passwd fallback
* `logind_seats`: seat records and watch hooks for greeter UI

## Power actions

`power_actions` routes shutdown, reboot, and suspend through logind policy checks.

## Greeter integration

`otter-greeter` composes these modules with `otter-ui` Surface Description. Lock screen (`otter-lock`) uses `PamAuth` only; greeter uses full `PamSession` plus session picker.

## Polkit and fprintd

`PolkitAgent` registers the desktop auth agent. `Fprintd` adds fingerprint auth for lock and polkit dialogs when hardware is there.