[VTPM] Make vTPM hotplug scripts use the UUID of the vTPM instance

Make the vTPM hotplug script use the UUID of the vTPM instance for
associating it with its instance number rather than the name of the
domain.
Also change the cleanup in the xm test to use the atexit mechanism
rather than explicitly calling a function to clean up.

Signed-off-by: Stefan Berger <stefanb@us.ibm.com>

tools/examples/vtpm-common.sh

@@ -20,7 +20,7 @@ dir=$(dirname "$0")
 . "$dir/logging.sh"
 . "$dir/locking.sh"
 
-VTPMDB="/etc/xen/vtpm.db"
+VTPMDB="/var/vtpm/vtpm.db"
 
 #In the vtpm-impl file some commands should be defined:
 #      vtpm_create, vtpm_setup, vtpm_start, etc. (see below)
@@ -241,12 +241,21 @@ function vtpm_get_create_reason () {
 # If no entry in the TPM database is found, the instance is
 # created and an entry added to the database.
 function vtpm_create_instance () {
-	local res instance domname reason
-	domname=$(xenstore_read "$XENBUS_PATH"/domain)
+	local res instance domname reason uuid
+	uuid=$(xenstore_read "$XENBUS_PATH"/uuid)
 	reason=$(vtpm_get_create_reason)
 
 	claim_lock vtpmdb
-	instance=$(vtpmdb_find_instance $domname)
+
+	instance="0"
+
+	if [ "$uuid" != "" ]; then
+		instance=$(vtpmdb_find_instance $uuid)
+	fi
+	if [ "$instance" == "0" ]; then
+		domname=$(xenstore_read "$XENBUS_PATH"/domain)
+		instance=$(vtpmdb_find_instance $domname)
+	fi
 
 	if [ "$instance" == "0" -a "$reason" != "create" ]; then
 		release_lock vtpmdb
@@ -268,7 +277,11 @@ function vtpm_create_instance () {
 		vtpm_create $instance
 
 		if [ $vtpm_fatal_error -eq 0 ]; then
-			vtpmdb_add_instance $domname $instance
+			if [ "$uuid" != "" ]; then
+				vtpmdb_add_instance $uuid $instance
+			else
+				vtpmdb_add_instance $domname $instance
+			fi
 		fi
 	else
 		if [ "$reason" == "resume" ]; then
@@ -288,22 +301,29 @@ function vtpm_create_instance () {
 #Since it is assumed that the VM will appear again, the
 #entry is kept in the VTPMDB file.
 function vtpm_remove_instance () {
-	local instance reason domname
+	local instance reason domname uuid
 	#Stop script execution quietly if path does not exist (anymore)
 	xenstore-exists "$XENBUS_PATH"/domain
-	domname=$(xenstore_read "$XENBUS_PATH"/domain)
+	uuid=$(xenstore_read "$XENBUS_PATH"/uuid)
 
-	if [ "$domname" != "" ]; then
-		claim_lock vtpmdb
+	claim_lock vtpmdb
 
-		instance=$(vtpmdb_find_instance $domname)
+	instance="0"
 
-		if [ "$instance" != "0" ]; then
-			vtpm_suspend $instance
-		fi
-
-		release_lock vtpmdb
+	if [ "$uuid != "" ]; then
+		instance=$(vtpmdb_find_instance $uuid)
 	fi
+
+	if [ "$instance == "0" ]; then
+		domname=$(xenstore_read "$XENBUS_PATH"/domain)
+		instance=$(vtpmdb_find_instance $domname)
+	fi
+
+	if [ "$instance" != "0" ]; then
+		vtpm_suspend $instance
+	fi
+
+	release_lock vtpmdb
 }