DVM: manage savefiles

Instead of hardcoded savefile name, use a symlink in
/var/run/qubes. Tools should set this symlink to a correct
savefile. Also, test whether the savefile is older than the
template root.img.

dom0/init.d/qubes_core

@@ -16,7 +16,27 @@
 # Source function library.
 . /etc/rc.d/init.d/functions
 
-
+setup_dvm_files()
+{
+    ROOT=/var/lib/qubes/dvmdata/savefile_root
+    DEFAULT=/var/lib/qubes/dvmdata/default_savefile
+    if ! [ -f $DEFAULT ] ; then return ; fi
+    if ! [ -f $ROOT ] ; then return ; fi
+    if [ $ROOT -nt $DEFAULT ] ; then
+        echo DVM require reconfiguration
+        return
+    fi
+    if [ -f /var/lib/qubes/dvmdata/dont_use_shm ] ; then
+        ln -s $DEFAULT /var/run/qubes/current_savefile
+    else
+    	mkdir -m 770 /dev/shm/qubes
+    	chown root.qubes /dev/shm/qubes
+    	cp $DEFAULT /dev/shm/qubes/current_savefile
+    	chown root.qubes /dev/shm/qubes/current_savefile
+    	chmod 660 /dev/shm/qubes/current_savefile
+    	ln -s /dev/shm/qubes/current_savefile /var/run/qubes/current_savefile
+    fi 
+}
 
 start()
 {
@@ -35,6 +55,7 @@ start()
     chmod 660 /var/run/qubes/dispVM_seq
     xm mem-set 0 800
     cp /var/lib/qubes/qubes.xml /var/lib/qubes/backup/qubes-$(date +%F-%T).xml
+    setup_dvm_files
     touch /var/lock/subsys/qubes_core
     success
     echo

dom0/pendrive_swapper/qfilexchgd

@@ -34,6 +34,7 @@ from qubes.qubes import QubesDaemonPidfile
 filename_seq = 50
 pen_cmd = '/usr/lib/qubes/qubes_pencmd'
 disposable_domains_dict = {}
+current_savefile = '/var/run/qubes/current_savefile'
 
 def get_next_filename_seq():
     global filename_seq
@@ -196,7 +197,7 @@ class DomainState:
             qvm_collection.unlock_db()
             return False
         retcode = subprocess.call(['/usr/bin/qubes_restore',
-            '/dev/shm/qubes/disposable_savefile',
+            current_savefile,
             '-c', vm.label.color,
             '-i', vm.label.icon,
             '-l', str(vm.label.index)])
@@ -230,8 +231,20 @@ class DomainState:
         return True
 
     def handle_transfer(self, vmname, transaction_seq):
+        dvmdata_dir = '/var/lib/qubes/dvmdata/'
         if vmname != 'disposable':
             return self.handle_transfer_regular(vmname, transaction_seq)
+        if not os.path.isfile(current_savefile):
+            subprocess.call(['/usr/bin/kdialog', '--sorry', 'There is no current savefile defined; run Qubes Manager'])
+            return False
+        if not os.path.isfile(dvmdata_dir+'default_savefile') or not os.path.isfile(dvmdata_dir+'savefile_root'):
+            subprocess.call(['/usr/bin/kdialog', '--sorry', 'Default savefile misconfiguration; run Qubes Manager'])
+            return False
+        dvm_mtime = os.stat(current_savefile).st_mtime
+        root_mtime = os.stat(dvmdata_dir+'savefile_root').st_mtime
+        if dvm_mtime < root_mtime:
+            subprocess.call(['/usr/bin/kdialog', '--sorry', 'Your current savefile is outdated, as you have updated the template VM. Run Qubes Manager and recreate the savefile'])
+            return False       
         return self.handle_transfer_disposable(transaction_seq)
 
 class XS_Watcher:

rpm_spec/core-dom0.spec

@@ -86,6 +86,7 @@ mkdir -p $RPM_BUILD_ROOT/var/lib/qubes/vm-templates
 mkdir -p $RPM_BUILD_ROOT/var/lib/qubes/appvms
 
 mkdir -p $RPM_BUILD_ROOT/var/lib/qubes/backup
+mkdir -p $RPM_BUILD_ROOT/var/lib/qubes/dvmdata
 
 mkdir -p $RPM_BUILD_ROOT/usr/share/qubes/icons
 cp icons/*.png $RPM_BUILD_ROOT/usr/share/qubes/icons
@@ -205,6 +206,7 @@ fi
 %attr(770,root,qubes) %dir /var/lib/qubes/vm-templates
 %attr(770,root,qubes) %dir /var/lib/qubes/appvms
 %attr(770,root,qubes) %dir /var/lib/qubes/backup
+%attr(770,root,qubes) %dir /var/lib/qubes/dvmdata
 %dir /usr/share/qubes/icons/*.png
 /etc/yum.repos.d/qubes.repo
 /usr/bin/qubes_setup_dnat_to_ns