Fix watchdog in the installer.

We only had one watchdog running that triggered after 30 minutes. If
an unattended upgrade (e.g. started by sysupgrade(8)) took longer than
this in total, the machine would reboot half way through an upgrade.
The intention was that the watchdog would be reset after each set
download and after each set installation. But this never worked
correctly because the actual upgrade ran in a sub-shell and WDPID was
not visible.
To fix this we first need to export WDPID to make it visible in the
sub-shell. Then reset_watchdog was guarded by $UU && reset_watchdog,
but UU wasn't visible either. But we can't export it because we would
enter a loop. We can just use the fact that WDPID is not empty to
restart the watchdog.
Lastly the watchdog process would keep stderr and stdout open. This
made the tee(1) hang that is collecting the autoupgrade log that is
mailed to root.
As a simplification, we don't need to run the watchdog as a
co-process, we don't want to communicate with it, we can just run it
in the background.
Problem reported by stsp
With & OK deraadt
OK millert

1 files changed, 13 insertions, 12 deletions

diff --git a/distrib/miniroot/install.sub b/distrib/miniroot/install.sub
index 4bc44f10942..e7ad9da30ae 100644
--- a/distrib/miniroot/install.sub
+++ b/distrib/miniroot/install.sub
@@ -1,5 +1,5 @@
 #!/bin/ksh
-#	$OpenBSD: install.sub,v 1.1195 2022/05/03 11:48:47 krw Exp $
+#	$OpenBSD: install.sub,v 1.1196 2022/05/05 20:07:23 florian Exp $
 #
 # Copyright (c) 1997-2015 Todd Miller, Theo de Raadt, Ken Westerback
 # Copyright (c) 2015, Robert Peichaer <rpe@openbsd.org>
@@ -1652,7 +1652,7 @@ install_files() {
 
 		# Fetch and verify the set files.
 		for _f in $_get_sets; do
-			$UU && reset_watchdog
+			reset_watchdog
 
 			rm -f /tmp/h /tmp/fail
 
@@ -1717,7 +1717,7 @@ install_files() {
 
 	# Install the set files.
 	for _f in $_get_sets; do
-		$UU && reset_watchdog
+		reset_watchdog
 		_fsrc="$_src/$_f"
 
 		# Take the set file from the prefetch area if possible.
@@ -1766,7 +1766,7 @@ install_files() {
 		cp ${_src#file://}/SHA256 /mnt/var/db/installed.SHA256
 	fi
 
-	$UU && reset_watchdog
+	reset_watchdog
 }
 
 # Fetch install sets from an HTTP server possibly using a proxy.
@@ -3304,6 +3304,7 @@ do_upgrade() {
 
 	# Perform final steps common to both an install and an upgrade.
 	finish_up
+	[[ -n $WDPID ]] && kill -KILL $WDPID 2>/dev/null
 }
 
 check_unattendedupgrade() {
@@ -3330,20 +3331,19 @@ WATCHDOG_PERIOD_SEC=$((30 * 60))
 
 # Restart the background timer.
 reset_watchdog() {
-	kill -KILL $WDPID 2>/dev/null
-	start_watchdog
+	if [[ -n $WDPID ]]; then
+		kill -KILL $WDPID 2>/dev/null
+		start_watchdog
+	fi
 }
 
-# Start a co-process to reboot a stalled sysupgrade.
+# Start a process to reboot a stalled sysupgrade.
 # This mechanism is only used during non-interactive sysupgrade.
 start_watchdog() {
 	(
-		sleep $WATCHDOG_PERIOD_SEC && reboot
-	) |&
+		sleep $WATCHDOG_PERIOD_SEC && echo WATCHDOG > /dev/tty && reboot
+	) >/dev/null 2>&1 &
 	WDPID=$!
-
-	# Close standard input of the co-process.
-	exec 3>&p; exec 3>&-
 }
 
 # ------------------------------------------------------------------------------
@@ -3496,6 +3496,7 @@ elif $UU; then
 	check_unattendedupgrade || exit 1
 
 	start_watchdog
+	export WDPID
 
 	get_responsefile
 	do_autoinstall