Fixed issues with gamescope not properly launching.

ptlinux/locking.py

@@ -7,7 +7,12 @@ from datetime import datetime
 import fcntl
 import os
 from pathlib import Path
-from typing import Iterator, TextIO
+from typing import Callable, Iterator, Sequence, TextIO
+
+
+ActiveGameProbe = Callable[[], bool]
+MAX_PROCESS_ENVIRONMENT_BYTES = 1024 * 1024
+MAX_PROCESS_COMMAND_BYTES = 128 * 1024
 
 
 class OperationBusyError(RuntimeError):
@@ -51,9 +56,22 @@ class LauncherPlayLease:
 	def record_owned(self) -> bool:
 		return self._record_owned
 
+	@property
+	def inherited_fds(self) -> tuple[int, ...]:
+		"""Keep the shared lease alive in the launched game supervisor."""
+
+		if self._handle is None:
+			return ()
+		return (self._handle.fileno(),)
+
 
 @contextmanager
-def launcher_operation_lock(lock_path: Path, operation: str) -> Iterator[None]:
+def launcher_operation_lock(
+	lock_path: Path,
+	operation: str,
+	*,
+	active_game_probe: ActiveGameProbe | None = None,
+) -> Iterator[None]:
 	lock_path.parent.mkdir(parents=True, exist_ok=True)
 	with lock_path.open("a+", encoding="utf-8") as handle:
 		try:
@@ -64,6 +82,11 @@ def launcher_operation_lock(lock_path: Path, operation: str) -> Iterator[None]:
 			raise OperationBusyError(
 				f"launcher files are busy ({owner}); wait for it to finish and try again"
 			) from exc
+		if active_game_probe is not None and active_game_probe():
+			raise OperationBusyError(
+				"launcher files are busy (active managed game client detected); "
+				"close every game client and try again"
+			)
 		_write_owner(handle, operation)
 		try:
 			yield
@@ -78,6 +101,8 @@ def launcher_operation_lock(lock_path: Path, operation: str) -> Iterator[None]:
 def launcher_play_lock(
 	lock_path: Path,
 	operation: str = "play",
+	*,
+	active_game_probe: ActiveGameProbe | None = None,
 ) -> Iterator[LauncherPlayLease]:
 	"""Serialize preparation, then allow multiple active game clients.
 
@@ -105,12 +130,24 @@ def launcher_play_lock(
 				record_owned=False,
 			)
 		else:
-			_write_owner(handle, f"{operation} preparation")
-			lease = LauncherPlayLease(
-				handle,
-				preparation_allowed=True,
-				record_owned=True,
-			)
+			if active_game_probe is not None and active_game_probe():
+				# A game from an older launcher may have outlived its Python
+				# supervisor and therefore its inherited lock. Rejoin that live
+				# prefix without mutating its runtime view or waiting for it to exit.
+				_write_owner(handle, operation)
+				fcntl.flock(handle.fileno(), fcntl.LOCK_SH)
+				lease = LauncherPlayLease(
+					handle,
+					preparation_allowed=False,
+					record_owned=True,
+				)
+			else:
+				_write_owner(handle, f"{operation} preparation")
+				lease = LauncherPlayLease(
+					handle,
+					preparation_allowed=True,
+					record_owned=True,
+				)
 		try:
 			yield lease
 		finally:
@@ -123,6 +160,79 @@ def launcher_play_lock(
 			fcntl.flock(handle.fileno(), fcntl.LOCK_UN)
 
 
+def managed_game_process_is_active(
+	runtime_view: Path,
+	wine_prefixes: Sequence[Path],
+	*,
+	process_root: Path = Path("/proc"),
+) -> bool:
+	"""Detect a managed Wine game that outlived its launcher supervisor."""
+
+	prefixes = {_normalized_path(prefix) for prefix in wine_prefixes}
+	prefixes.discard("")
+	if not prefixes:
+		return False
+	runtime_marker = _normalized_path(runtime_view).casefold().replace("\\", "/")
+	if not runtime_marker:
+		return False
+	runtime_marker = runtime_marker.rstrip("/") + "/"
+	try:
+		processes = tuple(process_root.iterdir())
+	except OSError:
+		return False
+	for process in processes:
+		if not process.name.isdecimal():
+			continue
+		try:
+			name = (process / "comm").read_text(
+				encoding="utf-8",
+				errors="replace",
+			).strip().casefold()
+		except OSError:
+			continue
+		if not name.endswith(".exe"):
+			continue
+		environment = _read_bounded(process / "environ", MAX_PROCESS_ENVIRONMENT_BYTES)
+		if environment is None:
+			continue
+		wine_prefix = next(
+			(
+				entry.removeprefix(b"WINEPREFIX=")
+				for entry in environment.split(b"\0")
+				if entry.startswith(b"WINEPREFIX=")
+			),
+			None,
+		)
+		if (
+			wine_prefix is None
+			or _normalized_path(os.fsdecode(wine_prefix)) not in prefixes
+		):
+			continue
+		command = _read_bounded(process / "cmdline", MAX_PROCESS_COMMAND_BYTES)
+		if command is None:
+			continue
+		normalized_command = os.fsdecode(command).casefold().replace("\\", "/")
+		if runtime_marker in normalized_command:
+			return True
+	return False
+
+
+def _read_bounded(path: Path, maximum_bytes: int) -> bytes | None:
+	try:
+		with path.open("rb") as handle:
+			value = handle.read(maximum_bytes + 1)
+	except OSError:
+		return None
+	return value if len(value) <= maximum_bytes else None
+
+
+def _normalized_path(path: Path | str) -> str:
+	value = str(path)
+	if not value:
+		return ""
+	return str(Path(value).expanduser().resolve(strict=False))
+
+
 def _read_owner(handle: TextIO) -> str:
 	handle.seek(0)
 	return handle.read().strip() or "unknown operation"