# Windows service (deployment)

The `PunktfunkHost` Windows service is the end-user way to run the host on Windows. It replaces the
manual bring-up chain (a scheduled task → `PsExec64 -s -i 1` → `wscript launch.vbs` → `host-run.cmd`)
with one command, auto-start on boot, and supervision.

## Install (installer — recommended)

Download the signed installer from the package registry
(`punktfunk-host-windows`, <https://git.unom.io/unom/-/packages>) and run it (it elevates itself):

```
punktfunk-host-setup-<ver>.exe              # wizard
punktfunk-host-setup-<ver>.exe /VERYSILENT  # unattended
```

It lays the host into `C:\Program Files\punktfunk`, optionally installs the bundled **SudoVDA**
virtual-display driver, then runs `service install` + `service start` for you. Upgrades stop the
service first and re-point it; uninstall (Add/Remove Programs) runs `service uninstall`. Packaging
details: [`packaging/windows/README.md`](../packaging/windows/README.md). A self-signed CI build also
publishes a `.cer` — import it once (`Import-Certificate -FilePath punktfunk-host-windows.cer
-CertStoreLocation Cert:\LocalMachine\TrustedPublisher`) so Windows trusts the signed setup.

## Install (manual / CLI)

From an **elevated** (Administrator) prompt:

```powershell
punktfunk-host service install   # register auto-start LocalSystem service + firewall rules + default host.env
punktfunk-host service start     # start it now (also starts automatically on every boot)
```

`service install` is idempotent — run it again after upgrading the exe to re-point the service at the
new binary. Register whatever location you keep the exe in (e.g. `C:\Program Files\punktfunk\`); the
service records the current exe path.

Other subcommands:

```powershell
punktfunk-host service stop
punktfunk-host service status
punktfunk-host service uninstall   # stop + delete the service + remove its firewall rules
```

## How it works

The host must run **as SYSTEM in the interactive session** (Session 1+): Desktop Duplication of the
secure desktop (UAC / lock / login) and `SendInput` need SYSTEM, and capture/injection need the
interactive session, which a plain Session-0 service is not in.

So the service (itself in Session 0) **never captures**. On start, and whenever the active console
session changes, it:

1. resolves the active console session (`WTSGetActiveConsoleSessionId`),
2. duplicates its own LocalSystem token and retargets it to that session (`SetTokenInformation`
   `TokenSessionId`),
3. launches the host there with `CreateProcessAsUserW` (`lpDesktop = winsta0\default`),
4. supervises it: relaunches on exit/crash (with backoff) and on a console connect/disconnect.

A kill-on-close **job object** ensures a service crash never orphans the SYSTEM host. The host in turn
spawns the WGC helper into the *user* session (see [`windows-secure-desktop.md`](windows-secure-desktop.md))
— two nested launches. Lock/unlock are handled inside the host (the `DesktopWatcher` DDA↔WGC mux), so
the service deliberately does **not** relaunch on lock/unlock — only on a real session switch.

This is the same model Sunshine/Apollo use.

## Configuration

Config lives in **`%ProgramData%\punktfunk\host.env`** (KEY=VALUE lines, `#` comments). `service
install` writes a default if none exists. Template: [`scripts/windows/host.env.example`](../scripts/windows/host.env.example).

```ini
PUNKTFUNK_ENCODER=nvenc
PUNKTFUNK_VIDEO_SOURCE=virtual
PUNKTFUNK_SECURE_DDA=1
RUST_LOG=info
# PUNKTFUNK_HOST_CMD=serve --native    # the host subcommand the service launches (default)
```

The service loads these into its environment and carries `PUNKTFUNK_*` + `RUST_LOG` to the host child
(the same env-merge the WGC helper uses). Restart the service after editing:

```powershell
punktfunk-host service stop; punktfunk-host service start
```

The host's identity (cert/pairing/mgmt token/library) also lives under `%ProgramData%\punktfunk` — a
machine-wide dir the SYSTEM service and the interactive user share, surviving user logout.
`PUNKTFUNK_CONFIG_DIR` overrides the location (both platforms; handy for tests).

## Logs

- `%ProgramData%\punktfunk\logs\service.log` — the service's own supervision log (spawn/exit/session
  switches).
- `%ProgramData%\punktfunk\logs\host.log` — the host child's stdout/stderr.

## Prerequisites

- The host built with `--features nvenc` for NVENC (the driver ships `nvEncodeAPI64.dll`; no SDK
  needed at runtime). Software encode otherwise.
- The **SudoVDA** indirect display driver installed (for `PUNKTFUNK_VIDEO_SOURCE=virtual`).
- **ViGEmBus** for virtual gamepads (optional).

## Gotchas

- `service install`/`uninstall` need an **elevated** prompt (the SCM rejects non-admin).
- `service run` is the SCM entry point — don't run it by hand (it errors with a hint).
- A **graceful** stop currently `TerminateProcess`es the host, so its RAII teardown (SudoVDA monitor
  REMOVE) doesn't run; a stale virtual monitor can linger until the next start. A cooperative-stop
  signal is a follow-up.