Replace tty0 with tty1 when starting getty

1) tty0 points to current virtual console. it is not a problem when getty
is started very early before pillar/monitor are started however under
following conditions it causes problems:
1. there is NO 'getty' specified on kernel command line
2. there is console=tty0 specified
3. debug.enable.console=true is set

if all 3 are true then getty is started by pillar AFTER monitor app is
started on tty2 and since tty0 points to tty2 in this case getty revokes
console from monitor app and the output gets corrupted

2) we cannot use /dev/console from rungetty.sh anymore because it
corrupts tty2 when running from pillar. Instead we use /dev/tty so
the logs will be redirected to proper stdout and it should work in both
cases: when getty is started by 'getty' parameter and when it is started
from context of pillar. In later case logs will appear from pillar
context which is correct

Signed-off-by: Mikhail Malyshev <mike.malyshev@gmail.com>

pkg/dom0-ztools/rootfs/usr/bin/rungetty.sh

@@ -15,17 +15,26 @@ start_getty() {
 	term="linux"
 	[ "$speed" = "$1" ] && speed=115200
 
+	# if console=tty0 is specified on the kernel command line, we should not start a getty on tty0
+	# but instead start it on the first available tty. tty0 points to the current console, so if
+	# we start a getty from pillar of debug.enable.console=true we may start it on current tty
+	# which may be occupied by TUI monitor application and tty will be taken away by getty.
+	# replacing tty0 with tty1 should be ok because this is the user's intention
+	if [ "$tty" = "tty0" ]; then
+        tty="tty1"
+    fi
+
 	# did we already process this tty?
 	if $(echo "${PROCESSEDTTY}" | grep -q -w "$tty"); then
-		echo "getty: already processed tty for $tty, not starting twice" | tee /dev/console
+		echo "getty: already processed tty for $tty, not starting twice" | tee /dev/tty
 		return
 	fi
 	# now indicate that we are processing it
 	PROCESSEDTTY="${PROCESSEDTTY} ${tty}"
 
 	# does the device even exist?
 	if [ ! -c /dev/$tty ]; then
-		echo "getty: cmdline has console=$tty but /dev/$tty is not a character device; not starting getty for $tty" | tee /dev/console
+		echo "getty: cmdline has console=$tty but /dev/$tty is not a character device; not starting getty for $tty" | tee /dev/tty
 		return
 	fi