dom0: create volatile.img if not exists (StandaloneVM case)

StandaloneVM have no template to get clean volatile.img. Normally it is copied
from template during VM creation, but it can happen that image would not extx
(e.g. after backup restore). So create it from scratch.

Stay with original approach (restoring from clean image of template) for other
cases as it is much simpler (and perhaps faster).

dom0/aux-tools/prepare_volatile_img.sh

@@ -0,0 +1,36 @@
+#!/bin/sh
+
+if [ "`id -u`" != "0" ]; then
+	exec sudo $0 $*
+fi
+
+set -e
+
+FILENAME=$1
+ROOT_SIZE=$2
+SWAP_SIZE=$[ 1024 ]
+
+if [ -z "$ROOT_SIZE" -o -z "$FILENAME" ]; then
+	echo "Usage: $0 <filename> <root.img size in MB>"
+	exit 1
+fi
+
+if [ -e "$FILENAME" ]; then
+	echo "$FILENAME already exists, not overriding"
+	exit 1
+fi
+
+TOTAL_SIZE=$[ $ROOT_SIZE + $SWAP_SIZE + 512 ]
+truncate -s ${TOTAL_SIZE}M "$FILENAME"
+sfdisk --no-reread -u M "$FILENAME" > /dev/null 2> /dev/null <<EOF
+0,${SWAP_SIZE},S
+,${ROOT_SIZE},L
+EOF
+
+kpartx -s -a "$FILENAME"
+loopdev=`losetup -j "$FILENAME"|tail -n 1 |cut -d: -f1`
+looppart=`echo $loopdev|sed 's:dev:dev/mapper:'`
+mkswap -f ${looppart}p1 > /dev/null
+kpartx -s -d ${loopdev}
+losetup -d ${loopdev} || :
+chown --reference `dirname "$FILENAME"` "$FILENAME"

dom0/qvm-core/qubes.py

@@ -106,6 +106,7 @@ dom0_vm = None
 qubes_appmenu_create_cmd = "/usr/lib/qubes/create_apps_for_appvm.sh"
 qubes_appmenu_remove_cmd = "/usr/lib/qubes/remove_appvm_appmenus.sh"
 qubes_pciback_cmd = '/usr/lib/qubes/unbind_pci_device.sh'
+prepare_volatile_img_cmd = '/usr/lib/qubes/prepare_volatile_img.sh'
 
 yum_proxy_ip = '10.137.255.254'
 yum_proxy_port = '8082'
@@ -1238,6 +1239,15 @@ class QubesVm(object):
 
         # Only makes sense on template based VM
         if source_template is None:
+            # For StandaloneVM create it only if not already exists (eg after backup-restore)
+            if not os.path.exists(self.volatile_img):
+                if verbose:
+                    print >> sys.stderr, "--> Creating volatile image: {0}...".format (self.volatile_img)
+                f_root = open (self.root_img, "r")
+                f_root.seek(0, os.SEEK_END)
+                root_size = f_root.tell()
+                f_root.close()
+                subprocess.check_call([prepare_volatile_img_cmd, self.volatile_img, str(root_size / 1024 / 1024)])
             return
 
         if verbose:

rpm_spec/core-dom0.spec

@@ -145,6 +145,7 @@ cp aux-tools/remove_appvm_appmenus.sh $RPM_BUILD_ROOT/usr/lib/qubes
 cp aux-tools/cleanup_dispvms $RPM_BUILD_ROOT/usr/lib/qubes
 cp aux-tools/startup-dvm.sh $RPM_BUILD_ROOT/usr/lib/qubes
 cp aux-tools/startup-misc.sh $RPM_BUILD_ROOT/usr/lib/qubes
+cp aux-tools/prepare_volatile_img.sh $RPM_BUILD_ROOT/usr/lib/qubes
 cp qmemman/server.py $RPM_BUILD_ROOT/usr/lib/qubes/qmemman_daemon.py
 cp ../misc/meminfo-writer $RPM_BUILD_ROOT/usr/lib/qubes/
 cp ../qrexec/qrexec_daemon $RPM_BUILD_ROOT/usr/lib/qubes/
@@ -440,6 +441,7 @@ fi
 /usr/lib/qubes/fix_dir_perms.sh
 /usr/lib/qubes/startup-dvm.sh
 /usr/lib/qubes/startup-misc.sh
+/usr/lib/qubes/prepare_volatile_img.sh
 %attr(4750,root,qubes) /usr/lib/qubes/qfile-dom0-unpacker
 %if %{use_systemd}
 %{_unitdir}/qubes-block-cleaner.service