From 6a2b39b96e50d4b248defab42a369e716a9b1180 Mon Sep 17 00:00:00 2001
From: Pratyush Anand <panand@redhat.com>
Date: Wed, 20 Jul 2016 23:42:21 +0530
Subject: [PATCH] kdumpctl: force rebuild in case of watchdog state change

If state of a watchdog device is changed by an user after kdumpctl restart
then initramfs must be rebuilt on the basis of new watchdog status.

Testing:
-------------------------------------------------------
Initramfs	wdt state
		Prev	Current		Result
-------------------------------------------------------
Not Exist	NA	X		Rebuild
Exist		Inact	Inact		No Rebuild
Exist		Inact	Act		Force Rebuild
Exist		Act	Inact		Force Rebuild
Exist		Act	Act(Same wdt)	No Rebuild
Exist		Act	Act(Diff wdt)	Force Rebuild
Exist		Act	Module Removed	Force Rebuild

Signed-off-by: Pratyush Anand <panand@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
---
 kdumpctl | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/kdumpctl b/kdumpctl
index c8fc54f..0436bfc 100755
--- a/kdumpctl
+++ b/kdumpctl
@@ -427,6 +427,40 @@ check_dump_fs_modified()
 	return 1
 }
 
+check_wdt_modified()
+{
+	is_wdt_mod_omitted
+	[[ $? -eq 0 ]] && return 0
+	[[ -d /sys/class/watchdog/ ]] || return 0
+
+	for dir in /sys/class/watchdog/*; do
+		[[ -d "$dir" ]] || continue
+		[[ -f "$dir/state" ]] || continue
+		wdtdrv=$(< "$dir/device/modalias")
+		wdtdrv=$(modinfo $wdtdrv | grep filename | awk -F"kernel/" '{print $2}')
+		active=$(< "$dir/state")
+		# rebuild when:
+		# module for this watchdog is not found and watchdog is active
+		# module for this watchdog is found and watchdog is inactive
+		lsinitrd $TARGET_INITRD | grep $wdtdrv &> /dev/null
+		if [ $? -ne 0 ]; then
+			[[ "$active" =  "active" ]] && return 1
+		else
+			[[ "$active" =  "inactive" ]] && return 1
+		fi
+	done
+
+	# check if watchdog kernel module unloaded.
+	loaded_mods=$(lsinitrd $TARGET_INITRD -f etc/cmdline.d/00-watchdog.conf)
+	[[ -n $loaded_mods ]] && loaded_mods=$(echo $loaded_mods | awk -F"rd.driver.pre=" '{print $2}' | sed "s/,/ /g")
+	for mod in $loaded_mods ; do
+	       lsmod | grep $mod &> /dev/null
+	       [[ $? != 0 ]] && return 1
+        done
+
+	return 0
+}
+
 # returns 0 if system is not modified
 # returns 1 if system is modified
 # returns 2 if system modification is invalid
@@ -448,6 +482,12 @@ check_system_modified()
 		return $ret
 	fi
 
+	check_wdt_modified
+	if [ $? -ne 0 ]; then
+		echo "Detected change in watchdog state"
+		return 1
+	fi
+
 	return 0
 }