steam-backlog-enforcer/steam_backlog_enforcer/game_uninstall.py
Krzysztof kuhy Rudnicki 21fe2f7742 Stop the enforcer launching Steam and notifications as root
The enforce service runs as root (no User=) but sets DISPLAY=:0, so any GUI
it starts lands on the desktop session. Two resolvers disagreed about who to
drop privileges to:

  library_hider._resolve_desktop_user()  read STEAM_ENFORCER_DESKTOP_USER
  game_install._get_real_user()          read only SUDO_USER or USER

systemd sets neither of the latter, so _get_real_user() returned None under
the service and every `geteuid() == 0 and real_user and ...` guard fell
through to running as root. Steam answered with a zenity modal ("Cannot run
as root user", /usr/lib/steam/steam:261) on screen.

Confirmed from the live process tree: root `bash /usr/lib/steam/steam
-cef-disable-gpu ... steam://install/618510` with a root zenity child. It
never reached the journal, because that text goes to zenity and _run_as_user
sends child output to DEVNULL.

- _desktop_env: add resolve_desktop_user/desktop_uid/desktop_user_cmd. Only
  the argv builder is shared, never the spawn call: tests/_no_subprocess.py
  patches subprocess per module by name, so a spawn site in an unpatched
  module could fire a real `sudo -u kuhy steam`.
- game_install._get_real_user: delegate to the shared resolver. This alone
  also fixes the root `steam -silent` in _ensure_steam_running and the
  no-op os.chown on new appmanifests.
- _trigger_steam_install / enforcer.send_notification: drop privileges.
  send_notification had no DBUS_SESSION_BUS_ADDRESS, so it silently reached
  nobody for all six of its callers.
- _run_as_user: fail closed. Running unchanged as root when no desktop user
  resolves is what put the modal on screen; refuse and log instead.

Also stop the retry storm behind it. steamapps does not exist (Steam has
never completed sign-in), so is_game_installed() was always False and the
loop re-triggered every allowed game every pass: 1656 attempts in 30
minutes, service RSS 1.5 GB (peak 4.3 GB), a FileNotFoundError traceback
each time. Guard install_game and _reinstall_missing_allowed on
steam_library_ready() -- a missing library means no install can succeed by
any route, so this is a correctness check rather than a tuned retry limit.

The module splits here are forced by the pre-commit 250-line gate, which
blocks any commit touching an over-cap file: game_install, library_hider and
_enforce_loop were already over before this change. They are split by
responsibility (_cdp transport, _steam_launch lifecycle, _steam_process
spawning, _steam_errors, _steam_client, _game_names, game_uninstall,
_enforce_steps, _owned_apps_cache, _echo, _protected_apps). game_install and
library_hider re-export their old public names, so the 15 modules that
import from them are untouched by this commit.

Verified as real root under the unit's environment: argv is now
`sudo -u kuhy env DISPLAY=:0 ... xdg-open steam://install/...` for both the
installer and notify-send; three enforce passes spawn no process and log
once; _run_as_user refuses with no desktop user. After restart: 0 retries,
0 tracebacks, 0 root-owned files under ~/.local/share/Steam, RSS 342 MB.

1311 tests pass. _desktop_env and _steam_state at 100% branch coverage.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016A1EYiv7e7HGhET84oa9M3
2026-08-24 13:55:44 +02:00

175 lines
5.9 KiB
Python

"""Uninstalling games and querying what is installed.
Split out of :mod:`steam_backlog_enforcer.game_install` to keep both files
under the 250-line cap: that module owns getting a game *onto* disk, this one
owns taking it off and reporting what is there.
"""
from __future__ import annotations
import contextlib
import logging
import re
import shutil
from typing import TYPE_CHECKING
from steam_backlog_enforcer._game_names import _is_protected_name
from steam_backlog_enforcer._protected_apps import PROTECTED_APP_IDS
from steam_backlog_enforcer._steam_state import STEAMAPPS_PATH, _assert_not_real_steam
from steam_backlog_enforcer._whitelist import get_approved_exception_ids
if TYPE_CHECKING:
from pathlib import Path
logger = logging.getLogger(__name__)
# ──────────────────────────────────────────────────────────────
# Game uninstall management
# ──────────────────────────────────────────────────────────────
def get_installed_games() -> list[tuple[int, str]]:
"""Parse appmanifest files to find installed games.
Returns: list of (app_id, game_name) tuples.
"""
installed: list[tuple[int, str]] = []
for manifest_file in STEAMAPPS_PATH.glob("appmanifest_*.acf"):
with contextlib.suppress(OSError):
content = manifest_file.read_text(encoding="utf-8")
app_id_match = re.search(r'"appid"\s+"(\d+)"', content)
name_match = re.search(r'"name"\s+"([^"]+)"', content)
if app_id_match:
app_id = int(app_id_match.group(1))
name = name_match.group(1) if name_match else f"Unknown ({app_id})"
installed.append((app_id, name))
installed.sort(key=lambda x: x[1].lower())
return installed
def _read_install_dir(manifest: Path) -> Path | None:
"""Read installdir from a game's appmanifest file."""
if not manifest.exists():
return None
try:
content = manifest.read_text(encoding="utf-8")
match = re.search(r'"installdir"\s+"([^"]+)"', content)
if match:
return STEAMAPPS_PATH / "common" / match.group(1)
except OSError:
pass
return None
def _remove_manifest(manifest: Path, game_name: str, app_id: int) -> bool:
"""Remove a game manifest file.
Args:
manifest: Path to the appmanifest file.
game_name: Human-readable game name for logging.
app_id: Steam application ID.
"""
_assert_not_real_steam(manifest)
try:
if manifest.exists():
manifest.unlink()
logger.info(
"Removed manifest for %s (AppID=%d)", game_name or app_id, app_id
)
except OSError:
logger.exception("Failed to remove manifest for AppID=%d", app_id)
return False
return True
def _remove_game_dirs(install_dir: Path | None, app_id: int) -> bool:
"""Remove game installation directory and cache directories.
Args:
install_dir: Path to the game's install directory, or None.
app_id: Steam application ID.
"""
success = True
if install_dir and install_dir.is_dir():
_assert_not_real_steam(install_dir)
if _is_protected_name(install_dir.name):
logger.warning(
"Refusing to remove %s: name matches an allowed game", install_dir
)
return False
try:
shutil.rmtree(install_dir)
logger.info("Removed game files: %s", install_dir)
except OSError:
logger.exception("Failed to remove game dir %s", install_dir)
success = False
for subdir in ("shadercache", "compatdata"):
cache_path = STEAMAPPS_PATH / subdir / str(app_id)
if cache_path.is_dir():
_assert_not_real_steam(cache_path)
with contextlib.suppress(OSError):
shutil.rmtree(cache_path)
logger.debug("Removed %s/%d", subdir, app_id)
return success
def uninstall_game(app_id: int, game_name: str = "") -> bool:
"""Uninstall a single game by removing its manifest and game files.
Uses direct file removal instead of ``steam://uninstall`` URI to avoid
GUI popups and to work when Steam is not running.
"""
manifest = STEAMAPPS_PATH / f"appmanifest_{app_id}.acf"
install_dir = _read_install_dir(manifest)
success = _remove_manifest(manifest, game_name, app_id)
if not _remove_game_dirs(install_dir, app_id):
success = False
return success
def uninstall_other_games(allowed_app_ids: set[int]) -> int:
"""Uninstall all installed games except the allowed ones and protected IDs.
Args:
allowed_app_ids: Every app id that must survive — the assignment plus
any concurrent manual picks. Empty means "keep nothing".
Returns: number of games uninstalled.
"""
installed = get_installed_games()
count = 0
for app_id, name in installed:
if app_id in allowed_app_ids:
logger.info("KEEPING allowed game: %s (AppID=%d)", name, app_id)
continue
if is_protected_app(app_id):
logger.debug("Skipping protected: %s (AppID=%d)", name, app_id)
continue
logger.info("UNINSTALLING: %s (AppID=%d)", name, app_id)
if uninstall_game(app_id, name):
count += 1
return count
def is_protected_app(app_id: int) -> bool:
"""Return True if *app_id* must never be uninstalled.
Combines the hardcoded Steam infrastructure set with any app IDs that
have been approved via the time-locked exception mechanism.
Args:
app_id: Steam application ID to check.
Returns:
True if the app should be left alone by the enforcer.
"""
return app_id in PROTECTED_APP_IDS or app_id in get_approved_exception_ids()