sx: traps can explicitly set an exit status

The prior commit 666b87e would still fail if the sx program itself was
killed leaving an xorg server behind.  While trap handlers aren't
typically allowed to change the exit status, if we explicitly exit with
a value then it is honoured.

This works around the subshell setting an exit status of 138 (due to
SIGUSR1) by explicitly using the return value from the last wait or the
last command if the server never started at all.

sx

@@ -4,11 +4,18 @@
 # requires xauth Xorg
 
 cleanup() {
+    if [ "$pid" ] && kill -0 "$pid" 2> /dev/null; then
+        kill -s TERM "$pid"
+        wait "$pid"
+        r=$?
+    fi
+
     if ! stty "$stty"; then
         stty sane
     fi
 
     xauth remove :"$tty"
+    exit "${r:-$?}"
 }
 
 stty=$(stty -g)
@@ -24,8 +31,7 @@ export XAUTHORITY=${XAUTHORITY:-$cfgdir/xauthority}
 mkdir -p "$cfgdir" "${XAUTHORITY%/*}"
 touch "$XAUTHORITY"
 
-trap 'cleanup "$pid"' EXIT
-
+trap 'cleanup' EXIT
 xauth add :"$tty" MIT-MAGIC-COOKIE-1 "$(od -An -N16 -tx /dev/urandom | tr -d ' ')"
 
 # Xorg will check if its SIGUSR1 disposition is SIG_IGN and use this state to
@@ -34,14 +40,5 @@ xauth add :"$tty" MIT-MAGIC-COOKIE-1 "$(od -An -N16 -tx /dev/urandom | tr -d ' '
 # Taking advantage of this feature allows us to launch our client directly
 # from the SIGUSR1 handler and avoid the need to poll for server readiness.
 trap 'DISPLAY=:$tty "${@:-$cfgdir/sxrc}"' USR1
-(
-    trap '' USR1
-    exec /usr/lib/xorg-server/Xorg :"$tty" -keeptty vt"$tty" -noreset -auth "$XAUTHORITY"
-) & pid=$!
-
+(trap '' USR1 && exec /usr/lib/xorg-server/Xorg :"$tty" -keeptty vt"$tty" -noreset -auth "$XAUTHORITY") & pid=$!
 wait "$pid"
-
-if kill -0 "$pid" 2> /dev/null; then
-    kill -s TERM "$pid"
-    wait "$pid"
-fi