Merge remote-tracking branch 'qubesos/pr/33'

* qubesos/pr/33:
  qubes-dom0-update: Adapt template backup failsafe for R4

dom0-updates/qubes-dom0-update

@@ -30,6 +30,8 @@ ALL_OPTS="$*"
 YUM_ACTION=
 QVMRUN_OPTS=
 CLEAN=
+TEMPLATE=
+TEMPLATE_BACKUP=
 # Filter out some yum options and collect packages list
 while [ $# -gt 0 ]; do
     case "$1" in
@@ -70,25 +72,29 @@ if [ "$YUM_ACTION" == "reinstall" ] || [ "$YUM_ACTION" == "upgrade" ] || [ "$YUM
 
     ONEPKG=`cut -f 1 -d ' ' <<<$PKGS`
     if [[ "$ONEPKG" == "qubes-template-"* ]] && [[ "$ONEPKG" == "${PKGS#\ }" ]]; then # test "$PKGS" minus space
-    # Prepare to backup template root.img in case reinstall doesn't complete.
         ONEPKG=`sed -r 's/-[0-9]+(\.[0-9-]+)+(\.noarch)*$//' <<<$ONEPKG` # Remove version suffix
         TEMPLATE=${ONEPKG#qubes-template-} # Remove prefix
+
         if qvm-shutdown --wait $TEMPLATE ; then
             echo "Template VM halted"
         fi
-        if ! TEMPLATE_NETVM=`qvm-prefs --force-root $TEMPLATE netvm` \
-        || ! BAK_TEMPLATE_ROOT=`qvm-prefs --force-root $TEMPLATE root_img` \
-        || ! BAK_TEMPLATE_PRIVATE=`qvm-prefs --force-root $TEMPLATE private_img` ; then
-            exit 1
-        fi
-        if [[ "$TEMPLATE_NETVM" == *"(default)" ]] ; then
-            TEMPLATE_NETVM="default"
+
+        # Try to avoid unrecoverable failures when operating on the template of
+        # the UpdateVM by making a backup first.
+        UPDATEVM_TEMPLATE=$(qvm-prefs -- "$UPDATEVM" template 2>/dev/null)
+        if [ X"$UPDATEVM_TEMPLATE" = X"$TEMPLATE" ]; then
+            TEMPLATE_BACKUP="${TEMPLATE}-backup-$(date +%Y%m%d)-$(mktemp -u XXXX)"
+            TEMPLATE_BACKUP=${TEMPLATE_BACKUP:0:32}
+            echo "Attempting to operate on template of UpdateVM... backing up $TEMPLATE to $TEMPLATE_BACKUP"
+            if ! qvm-clone -- "$TEMPLATE" "$TEMPLATE_BACKUP"; then
+                echo "ERROR: Unable to make backup of UpdateVM template!" >&2
+                exit 1
+            fi
         fi
     else
         echo "ERROR: Specify only one package to reinstall template"
         exit 1
     fi
-
 else
     TEMPLATE_EXCLUDE_OPTS="--exclude=`rpm -qa --qf '%{NAME},' qubes-template-\*`"
 fi
@@ -183,44 +189,25 @@ if [ -z "$YUM_ACTION" ]; then
     YUM_ACTION=upgrade
 fi
 
-if [ "x$PKGS" != "x" ]; then
-    if [[ -n "$BAK_TEMPLATE_ROOT" ]] ; then # Handle template details
-    # Backup root.img and private.img just in case
-        echo "Creating img backup files"
-        mv "$BAK_TEMPLATE_ROOT" "$BAK_TEMPLATE_ROOT-bak"
-        mv "$BAK_TEMPLATE_PRIVATE" "$BAK_TEMPLATE_PRIVATE-bak"
-        TDIR=`qvm-prefs --force-root $TEMPLATE dir`
-        if [ -f "$TDIR/firewall.xml" ]; then
-            mv "$TDIR/firewall.xml" "$TDIR/firewall.xml-bak"
-        fi
-        rm -f "$TDIR/volatile.img"
-        echo "--> Creating private.img..."
-        truncate -s 2G $BAK_TEMPLATE_PRIVATE
-        mkfs.ext4 -m 0 -q -F $BAK_TEMPLATE_PRIVATE
-        chown root:qubes $BAK_TEMPLATE_PRIVATE
-        chmod 0660 $BAK_TEMPLATE_PRIVATE
+if [ -n "$PKGS" ]; then
+    if [ -n "$TEMPLATE" ]; then
+        TEMPLATE_NETVM=$(qvm-prefs --force-root $TEMPLATE netvm)
     fi
 
     dnf $YUM_OPTS $YUM_ACTION $PKGS ; RETCODE=$?
 
-    if [[ -n "$BAK_TEMPLATE_ROOT" ]] ; then # Handle template details
-        if [[ $RETCODE -eq 0 && -f "$BAK_TEMPLATE_ROOT" ]]; then
-        # Reinstall went OK, remove backup files.
-            rm -f "$BAK_TEMPLATE_ROOT-bak"
-            rm -f "$BAK_TEMPLATE_PRIVATE-bak"
-        else
-            echo "Yum exit: Restoring img files"
-            mv "$BAK_TEMPLATE_ROOT-bak" "$BAK_TEMPLATE_ROOT"
-            mv "$BAK_TEMPLATE_PRIVATE-bak" "$BAK_TEMPLATE_PRIVATE"
-        fi
-        if [ -f "$TDIR/firewall.xml-bak" ]; then
-            mv "$TDIR/firewall.xml-bak" "$TDIR/firewall.xml"
-        fi
-        if ! qvm-prefs --force-root -s $TEMPLATE netvm $TEMPLATE_NETVM ; then
-            echo "ERROR: NetVM setting could not be restored!"
+    if [ -n "$TEMPLATE_BACKUP" -a "$RETCODE" -eq 0 ]; then
+        # Remove backup, if we made one. Better to do this only on success and
+        # potentially leave extra backups around than do it on an exit trap and
+        # clean up more reliably but potentially brick a system.
+        qvm-remove -- "$TEMPLATE_BACKUP"
+    fi
+
+    if [ -n "$TEMPLATE" -a -n "$TEMPLATE_NETVM" -a x"$TEMPLATE_NETVM" != xNone ]; then
+        if ! qvm-prefs --force-root -s $TEMPLATE netvm $TEMPLATE_NETVM; then
+            echo "ERROR: NetVM setting could not be restored!" >&2
             exit 1
         fi
-        
     fi
 elif [ -f /var/lib/qubes/updates/repodata/repomd.xml ]; then
     # Above file exists only when at least one package was downloaded