fix(host): make client game launches work on every Linux compositor

Client-initiated launches (Hello.launch / GameStream applist) were only
wired to gamescope's bare-spawn path via the process-global
PUNKTFUNK_GAMESCOPE_APP env — which leaked across sessions, was never
read by kwin/mutter/wlroots (launch was a silent no-op there), and was
unreachable on gamescope anyway because apply_input_env unconditionally
defaulted to the managed session (which bails on non-Bazzite/SteamOS
boxes and ignores the launch command in all its modes).

- Thread the launch per-session: resolve the library id at handshake,
  carry it on SessionContext (Windows: id; else: resolved command), and
  hand it to the backend instance via set_launch_command — the global
  env write is gone (the env stays as an operator fallback in spawn).
- Gamescope sub-mode ladder (pick_gamescope_mode, pure + unit-tested):
  managed only when session-plus/SteamOS infra exists, attach for an
  explicit request or a foreign (non-host-descendant) gamescope, else
  bare spawn — which nests the launch and is now reachable on plain
  distros instead of the guaranteed managed-mode bail.
- launch_session_command: one launch entry point for both planes once
  capture is live — desktop compositors plain-spawn into the retargeted
  session (the virtual output is primary); managed/attached gamescope
  spawns with the live session's DISPLAY/GAMESCOPE_WAYLAND_DISPLAY
  discovered from /proc (steam:// URIs also forward over Steam's own
  pipe). launch_is_nested gates bare spawn against double-launching.
- GameStream unified onto the same dispatch; also nests library-id
  picks into gamescope (previously only apps.json cmd was nested).

Validated live on the dev box up to the missing-GPU wall: handshake
resolution, Spawn sub-mode on plain Ubuntu, gamescope spawned with the
command nested. On-glass validation (kwin spawn on the streamed output,
Bazzite/Deck managed forward) pending GPU reattach.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
This commit is contained in:
2026-07-01 22:02:52 +00:00
parent 7c976bc8c3
commit e7b07d2363
5 changed files with 443 additions and 120 deletions
+75 -41
View File
@@ -1639,55 +1639,89 @@ fn steam_exe() -> Option<std::path::PathBuf> {
None
}
/// Launch a GameStream `apps.json` command (operator-typed, trusted — never client-set) into the live
/// session, AFTER capture is up. Used by the GameStream path for the backends that DON'T nest the
/// command via [`VirtualDisplay::set_launch_command`]: Windows (no gamescope) and Linux
/// kwin/mutter/wlroots (which stream the existing desktop). The caller skips this for Linux gamescope,
/// which already nested it. On Windows it runs in the interactive USER session (the host is SYSTEM);
/// on Linux the host is already inside the user's graphical session, so a plain spawn lands the app on
/// the streamed (primary) output.
#[cfg(any(windows, target_os = "linux"))]
/// Launch a GameStream `apps.json` command (operator-typed, trusted — never client-set) into the
/// interactive Windows user session, AFTER capture is up (the host is SYSTEM). The Linux paths go
/// through the compositor-aware [`launch_session_command`] instead.
#[cfg(windows)]
pub fn launch_gamestream_command(cmd: &str) -> Result<()> {
let cmd = cmd.trim();
anyhow::ensure!(!cmd.is_empty(), "empty command");
#[cfg(windows)]
{
// cmd.exe /c is fine here: the value is the host operator's own apps.json command, not a
// client-influenced string (same trust as the custom-store `command` kind).
let pid = crate::interactive::spawn_in_active_session(&format!("cmd.exe /c {cmd}"), None)
.context("spawn gamestream command in the interactive session")?;
tracing::info!(command = %cmd, pid, "gamestream: launched app in the interactive session");
Ok(())
}
#[cfg(target_os = "linux")]
{
let child = std::process::Command::new("sh")
.arg("-c")
.arg(cmd)
.spawn()
.context("spawn gamestream command")?;
tracing::info!(command = %cmd, pid = child.id(), "gamestream: launched app into the session");
Ok(())
}
// cmd.exe /c is fine here: the value is the host operator's own apps.json command, not a
// client-influenced string (same trust as the custom-store `command` kind).
let pid = crate::interactive::spawn_in_active_session(&format!("cmd.exe /c {cmd}"), None)
.context("spawn gamestream command in the interactive session")?;
tracing::info!(command = %cmd, pid, "gamestream: launched app in the interactive session");
Ok(())
}
/// Launch a library title chosen from the **GameStream `/applist`** (the store-qualified id is carried
/// on the `AppEntry`, resolved from the numeric Moonlight appid). Windows spawns it into the interactive
/// user session ([`launch_title`]); Linux resolves its shell command ([`launch_command`]) and runs it
/// into the live session ([`launch_gamestream_command`]). The id is resolved against the host's OWN
/// library, so a client can only ever pick an existing title — never inject a command.
#[cfg(any(windows, target_os = "linux"))]
/// on the `AppEntry`, resolved from the numeric Moonlight appid) into the interactive Windows user
/// session ([`launch_title`]). The id is resolved against the host's OWN library, so a client can
/// only ever pick an existing title — never inject a command. Linux resolves the id via
/// [`launch_command`] and goes through [`launch_session_command`] instead.
#[cfg(windows)]
pub fn launch_gamestream_library(id: &str) -> Result<()> {
#[cfg(windows)]
{
launch_title(id)
}
#[cfg(target_os = "linux")]
{
let cmd = launch_command(id)
.ok_or_else(|| anyhow::anyhow!("library id '{id}' has no launch recipe"))?;
launch_gamestream_command(&cmd)
launch_title(id)
}
/// Launch a resolved shell command into the **live Linux session** for the session's compositor —
/// the one launch entry point shared by the native (punktfunk/1) and GameStream planes, called
/// AFTER capture is up so the app renders onto the streamed output. The command is host-resolved
/// (a library id via [`launch_command`], or an operator-typed apps.json/custom command) — never a
/// client-sent string. Best-effort by contract: a failure leaves the user on the (streamed)
/// desktop/session rather than tearing the stream down.
///
/// * **KWin / Mutter / wlroots** — the host runs inside the user's graphical session (the process
/// env was retargeted at it by `apply_session_env`, and the per-session virtual output is
/// promoted primary), so a plain spawn lands the app on the streamed output.
/// * **gamescope (managed / SteamOS / attach)** — the app must open *inside* the running gamescope
/// session: spawned with the session's own `DISPLAY`/Wayland env
/// ([`crate::vdisplay::launch_into_gamescope_session`]). A `steam steam://…` command additionally
/// forwards over the running Steam instance's own pipe, so the dominant Steam case is
/// env-independent.
/// * **gamescope (bare spawn)** — not routed here: the command was nested into the fresh gamescope
/// via `set_launch_command` (the caller gates on `vdisplay::launch_is_nested`).
#[cfg(target_os = "linux")]
pub fn launch_session_command(compositor: crate::vdisplay::Compositor, cmd: &str) -> Result<()> {
let cmd = cmd.trim();
anyhow::ensure!(!cmd.is_empty(), "empty command");
let child = match compositor {
crate::vdisplay::Compositor::Gamescope => {
crate::vdisplay::launch_into_gamescope_session(cmd)?
}
_ => std::process::Command::new("sh")
.arg("-c")
.arg(cmd)
.spawn()
.context("spawn launch command")?,
};
tracing::info!(
command = %cmd,
pid = child.id(),
compositor = compositor.id(),
"launched app into the live session"
);
Ok(())
}
/// Resolve the launch command for a session app selection on Linux: a store-qualified library id
/// (from either plane) wins, else the operator-typed command. `None` = nothing to launch (or an
/// unknown/recipe-less id — warned, so a client picking a stale title sees why nothing started).
#[cfg(target_os = "linux")]
pub fn resolve_session_launch(library_id: Option<&str>, command: Option<&str>) -> Option<String> {
if let Some(id) = library_id {
match launch_command(id) {
Some(cmd) => return Some(cmd),
None => tracing::warn!(
launch_id = id,
"requested launch id not in this host's library (or no launch recipe) — ignoring"
),
}
}
command
.map(str::trim)
.filter(|c| !c.is_empty())
.map(str::to_string)
}
/// The full library: every store's titles merged + the custom entries, sorted by title.