snapcraft: provide qemu-external plug connect/disconnect hooks

Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
(cherry picked from commit b4db1b5)

snapcraft/commands/daemon.start

@@ -173,6 +173,13 @@ echo "==> Preparing /run/bin"
 mkdir -p "/run/bin"
 export PATH="/run/bin:${PATH}"
 
+if [ -e "${SNAP_COMMON}/use-qemu-external-snap" ]; then
+    echo "==> Setting up external QEMU snap integration"
+    export SNAP_QEMU_PREFIX="external/qemu"
+    LD_LPATH_PIPEWIRE="$(readlink -f "${SNAP_CURRENT}"/${SNAP_QEMU_PREFIX}/lib/"${ARCH}"/pipewire-*/)"
+    export LD_LIBRARY_PATH="${SNAP_CURRENT}/${SNAP_QEMU_PREFIX}/lib/${ARCH}:${SNAP_CURRENT}/${SNAP_QEMU_PREFIX}/lib/${ARCH}/pulseaudio:${SNAP_CURRENT}/${SNAP_QEMU_PREFIX}/lib/${ARCH}/ceph:${LD_LPATH_PIPEWIRE:+${LD_LPATH_PIPEWIRE}:}${LD_LIBRARY_PATH}"
+fi
+
 if [ "${ceph_external:-"false"}" = "true" ]; then
     ln -s "${SNAP}/wrappers/run-host" "/run/bin/ceph"
     ln -s "${SNAP}/wrappers/run-host" "/run/bin/radosgw-admin"

snapcraft/hooks/connect-plug-qemu-external

@@ -0,0 +1,16 @@
+#!/bin/sh
+set -eu
+
+# Re-exec outside of apparmor confinement
+if [ -d /sys/kernel/security/apparmor ]; then
+  label="$(cat /proc/self/attr/current 2>/dev/null)"
+  if [ "$label" != "unconfined" ] && [ -n "${label##*(unconfined)}" ]; then
+    exec aa-exec -p unconfined -- "$0" "$@"
+  fi
+fi
+
+echo 1 > "${SNAP_COMMON}/use-qemu-external-snap"
+
+echo reload > "${SNAP_COMMON}/state"
+read -r PID < "${SNAP_COMMON}/lxd.pid"
+kill "$PID"

snapcraft/hooks/disconnect-plug-qemu-external

@@ -0,0 +1,16 @@
+#!/bin/sh
+set -eu
+
+# Re-exec outside of apparmor confinement
+if [ -d /sys/kernel/security/apparmor ]; then
+  label="$(cat /proc/self/attr/current 2>/dev/null)"
+  if [ "$label" != "unconfined" ] && [ -n "${label##*(unconfined)}" ]; then
+    exec aa-exec -p unconfined -- "$0" "$@"
+  fi
+fi
+
+rm -f "${SNAP_COMMON}/use-qemu-external-snap"
+
+echo reload > "${SNAP_COMMON}/state"
+read -r PID < "${SNAP_COMMON}/lxd.pid"
+kill "$PID"