vrunner: use QMP quit before SIGTERM in daemon_stop escalation

When the SHUTDOWN-via-virtio-serial poll window expires and the QEMU
process is still alive, send a QMP quit before SIGTERMing. Functionally
near-equivalent to SIGTERM at the process level (both converge on
qemu_system_killed() and a block-layer flush) but goes through QEMU's
monitor interface, which is the same mechanism hv_idle_shutdown() already
uses for idle-timeout shutdowns. Unifying the two escalation paths
makes the code easier to reason about — one channel for "ask QEMU to
exit cleanly," one fallback for "the monitor isn't responding."

QMP quit is NOT a replacement for the virtio-serial ===SHUTDOWN===
command: it stops QEMU without giving the guest a chance to run its
own graceful_shutdown() (which is what cleanly unmounts the state
disk). It's only an improvement over SIGTERM as the *fallback* when
the guest hasn't responded to the SHUTDOWN command within the poll
window. The full architectural fix — QMP system_powerdown driving an
ACPI handler in the guest that calls graceful_shutdown() — needs
guest-side acpid wiring and is tracked separately.

SIGTERM and SIGKILL remain as further fallbacks for cases where QMP
itself is unresponsive (e.g. older configs without a QMP socket, or
QEMU hung in a state where the monitor stops servicing commands).

Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>

1 files changed, 17 insertions, 1 deletions

diff --git a/recipes-containers/vcontainer/files/vrunner.sh b/recipes-containers/vcontainer/files/vrunner.sh
index 92db55d2..680fe509 100755
--- a/recipes-containers/vcontainer/files/vrunner.sh
+++ b/recipes-containers/vcontainer/files/vrunner.sh
@@ -633,7 +633,23 @@ daemon_stop() {
         done
     fi
 
-    # If still running after the graceful window, escalate.
+    # If still running after the graceful window, escalate via QMP quit.
+    # Functionally similar to SIGTERM at the QEMU-process level (both
+    # converge on qemu_system_killed and a block-layer flush), but goes
+    # through QEMU's monitor interface — the same path hv_idle_shutdown()
+    # uses. Keeps the two escalation paths consistent.
+    if kill -0 "$pid" 2>/dev/null; then
+        local qmp_sock="$DAEMON_SOCKET_DIR/qmp.sock"
+        if [ -S "$qmp_sock" ]; then
+            log "INFO" "Sending QMP quit..."
+            echo '{"execute":"qmp_capabilities"}{"execute":"quit"}' | \
+                socat - "UNIX-CONNECT:$qmp_sock" >/dev/null 2>&1 || true
+            sleep 2
+        fi
+    fi
+
+    # If QMP quit didn't take (or no QMP socket — older configs), fall
+    # back to SIGTERM.
     if kill -0 "$pid" 2>/dev/null; then
         log "INFO" "Sending SIGTERM..."
         kill "$pid" 2>/dev/null || true