runscript.sh: add chroot support

This adds support for a chroot variable which will be passed to the
start-stop-daemon --chroot switch to runscript.sh when starting a
daemon. This also needs to be saved so it can be used in locating the
pid file when stopping the daemon.

X-Gentoo-Bug: 524388
X-Gentoo-Bug-URL: https://bugs.gentoo.org/show_bug.cgi?id=524388

man/openrc-run.8

@@ -120,6 +120,9 @@ Set this to "true", "yes" or "1" (case-insensitive) to force the daemon into
 the background. This implies the "--make-pidfile" and "--pidfile" option of
 .Xr start-stop-daemon 8
 so the pidfile variable must be set.
+.It Ar chroot
+.Xr start-stop-daemon 8
+will chroot into this path before writing the pid file or starting the daemon.
 .It Ar pidfile
 Pidfile to use for the above defined command.
 .It Ar name

sh/runscript.sh.in

@@ -142,12 +142,14 @@ start()
 	fi
 	eval start-stop-daemon --start \
 		--exec $command \
+		${chroot:+--chroot} $chroot \
 		${procname:+--name} $procname \
 		${pidfile:+--pidfile} $pidfile \
 		$_background $start_stop_daemon_args \
 		-- $command_args
 	if eend $? "Failed to start $RC_SVCNAME"; then
 		service_set_value "command" "${command}"
+		[ -n "${chroot}" ] && service_set_value "chroot" "${chroot}"
 		[ -n "${pidfile}" ] && service_set_value "pidfile" "${pidfile}"
 		[ -n "${procname}" ] && service_set_value "procname" "${procname}"
 		return 0
@@ -163,9 +165,11 @@ start()
 stop()
 {
 	local startcommand="$(service_get_value "command")"
+	local startchroot="$(service_get_value "chroot")"
 	local startpidfile="$(service_get_value "pidfile")"
 	local startprocname="$(service_get_value "procname")"
 	command="${startcommand:-$command}"
+	chroot="${startchroot:-$chroot}"
 	pidfile="${startpidfile:-$pidfile}"
 	procname="${startprocname:-$procname}"
 	[ -n "$command" -o -n "$procname" -o -n "$pidfile" ] || return 0
@@ -174,7 +178,7 @@ stop()
 		${retry:+--retry} $retry \
 		${command:+--exec} $command \
 		${procname:+--name} $procname \
-		${pidfile:+--pidfile} $pidfile \
+		${pidfile:+--pidfile} $chroot$pidfile \
 		${stopsig:+--signal} $stopsig
 	eend $? "Failed to stop $RC_SVCNAME"
 }