Fix error on installer abort/exit

^C during questiong yields
	/install: /tmp/cppid: cannot open $(<) input

The trap handler must first test existence, then read the PID file.
Quote like other PID file constructs in install.sub do.

Use newlines to make the trap function readable.

OK miod

diff --git a/distrib/miniroot/install.sub b/distrib/miniroot/install.sub
index 8a24248..c5d0d7f 100644 (file)
--- a/distrib/miniroot/install.sub
+++ b/distrib/miniroot/install.sub
@@ -1,5 +1,5 @@
 #!/bin/ksh
-#      $OpenBSD: install.sub,v 1.1233 2023/03/09 19:49:57 naddy Exp $
+#      $OpenBSD: install.sub,v 1.1234 2023/03/10 10:33:40 kn Exp $
 #
 # Copyright (c) 1997-2015 Todd Miller, Theo de Raadt, Ken Westerback
 # Copyright (c) 2015, Robert Peichaer <rpe@openbsd.org>
@@ -557,8 +557,15 @@ unlock() {
 
 # Add a trap to kill the dmesg listener co-process on exit of the installer.
 retrap() {
-       trap '_cppid=$(</tmp/cppid); if [ -n $_cppid ]; then kill -KILL -$_cppid 2>/dev/null; rm -f /tmp/cppid; fi; echo; stty echo; exit 0' \
-               INT EXIT TERM
+       trap '
+               if [[ -f /tmp/cppid ]]; then
+                       kill -KILL -"$(</tmp/cppid)" 2>/dev/null
+                       rm -f /tmp/cppid
+               fi
+               echo
+               stty echo
+               exit 0
+       ' INT EXIT TERM
 }
 
 # Start a listener process looking for dmesg changes which indicates a possible