Initial Commit

vm/host/owuivm-powerdown

@@ -0,0 +1,57 @@
+#!/bin/bash
+# =====================================================================
+# Presses the virtual power button, from the unit's ExecStop=.
+#
+# WHY THIS EXISTS
+#
+# Stopping the unit used to SIGTERM qemu, which from inside the machine
+# is indistinguishable from pulling the plug out of the wall. For a
+# session that is fine - the overlay is thrown away either side of it -
+# but a MAINTENANCE boot is the operator editing the base image that
+# every future session runs from, and yanking power on that is how a
+# frozen image acquires a dirty filesystem, or a half-written registry.
+#
+# ExecStop= runs while the main process is still alive, so this sends
+# `system_powerdown` over QMP and returns. systemd then waits for qemu
+# to exit by itself, up to TimeoutStopSec - and if the guest ignores the
+# button, or has already hung, the SIGTERM still happens afterwards. So
+# this is a courtesy with a deadline, not a new way to get stuck.
+#
+# Deliberately never fails: a stop path that can error is a stop path
+# that leaves the unit in `failed` and the next start blocked.
+# =====================================================================
+set -u
+
+SESSION="${1:-${OWUIVM_SESSION:-}}"
+[[ "$SESSION" =~ ^[0-9a-f]{32}$ ]] || exit 0
+SOCK="/run/owuivm/$SESSION/qmp.sock"
+[ -S "$SOCK" ] || exit 0
+
+/usr/bin/python3 - "$SOCK" <<'PY' 2>/dev/null || true
+import json, socket, sys, time
+path = sys.argv[1]
+try:
+    s = socket.socket(socket.AF_UNIX); s.settimeout(5); s.connect(path)
+    f = s.makefile("rwb")
+    f.readline()                                    # greeting
+    f.write(b'{"execute":"qmp_capabilities"}\n'); f.flush(); f.readline()
+    f.write(b'{"execute":"system_powerdown"}\n'); f.flush(); f.readline()
+    # Give the guest a moment to notice the button before systemd starts
+    # counting; an OS that has begun shutting down will not be helped by
+    # being asked twice.
+    deadline = time.monotonic() + 90
+    while time.monotonic() < deadline:
+        f.write(b'{"execute":"query-status"}\n'); f.flush()
+        line = f.readline()
+        if not line:
+            break                                   # qemu has gone: done
+        try:
+            if not (json.loads(line).get("return") or {}).get("running", True):
+                break
+        except ValueError:
+            pass
+        time.sleep(1)
+except Exception:
+    pass
+PY
+exit 0