dom0/qvm-core: ignore stderr from VM commands when not needed for sure (#626)

pam_systemd.so has a bug, which cause spurious '...killed' output on stderr.

dom0/qvm-core/qubes.py

@@ -1301,9 +1301,14 @@ class QubesVm(object):
 
         return conf
 
-    def run(self, command, verbose = True, autostart = False, notify_function = None, passio = False, passio_popen = False, localcmd = None, wait = False, gui = True):
+    def run(self, command, verbose = True, autostart = False, notify_function = None, passio = False, passio_popen = False, passio_stderr=False, ignore_stderr=False, localcmd = None, wait = False, gui = True):
-        """command should be in form 'user:cmdline'"""
+        """command should be in form 'user:cmdline'
+            When passio_popen=True, popen object with stdout connected to pipe.
+            When additionally passio_stderr=True, stderr also is connected to pipe.
+            When ignore_stderr=True, stderr is connected to /dev/null.
+            """
 
+        null = None
         if not self.is_running():
             if not autostart:
                 raise QubesException("VM not running")
@@ -1330,12 +1335,28 @@ class QubesVm(object):
         if passio:
             os.execv(qrexec_client_path, args)
             exit(1)
+
+        call_kwargs = {}
+        if ignore_stderr:
+            null = open("/dev/null", "w")
+            call_kwargs['stderr'] = null
+
         if passio_popen:
-            p = subprocess.Popen (args, stdout=subprocess.PIPE)
+            popen_kwargs={'stdout': subprocess.PIPE}
+            if passio_stderr:
+                popen_kwargs['stderr'] = subprocess.PIPE
+            else:
+                popen_kwargs['stderr'] = call_kwargs.get('stderr', None)
+            p = subprocess.Popen (args, **popen_kwargs)
+            if null:
+                null.close()
             return p
         if not wait:
             args += ["-e"]
-        return subprocess.call(args)
+        retcode = subprocess.call(args, **call_kwargs)
+        if null:
+            null.close()
+        return retcode
 
     def attach_network(self, verbose = False, wait = True, netvm = None):
         if dry_run:

dom0/qvm-tools/qubes-dom0-update

@@ -75,7 +75,7 @@ echo "Checking for dom0 updates" >&2
 # Start VM if not running already
 qvm-run -a $UPDATEVM true || exit 1
 
-/usr/lib/qubes/qrexec_client -d "$UPDATEVM" -l 'tar c /var/lib/rpm /etc/yum.repos.d /etc/yum.conf 2>/dev/null' 'user:tar x -C /var/lib/qubes/dom0-updates'
+/usr/lib/qubes/qrexec_client -d "$UPDATEVM" -l 'tar c /var/lib/rpm /etc/yum.repos.d /etc/yum.conf 2>/dev/null' 'user:tar x -C /var/lib/qubes/dom0-updates' 2> /dev/null
 
 qvm-run --pass-io $UPDATEVM "/usr/lib/qubes/qubes_download_dom0_updates.sh --doit --nogui $ALL_OPTS"
 RETCODE=$?

dom0/qvm-tools/qvm-sync-clock

@@ -64,14 +64,14 @@ def main():
 
     # Ignore retcode, try even if nm-online failed - user can setup network manually
     #  on-online has timeout 30sec by default
-    net_vm.run('user:nm-online -x', verbose=verbose, wait=True)
+    net_vm.run('user:nm-online -x', verbose=verbose, wait=True, ignore_stderr=True)
 
     # Sync clock
-    if clock_vm.run('root:QUBESRPC qubes.SyncNtpClock dom0', verbose=verbose, wait=True) != 0:
+    if clock_vm.run('root:QUBESRPC qubes.SyncNtpClock dom0', verbose=verbose, wait=True, ignore_stderr=True) != 0:
         print >> sys.stderr, 'Time sync failed, aborting!'
         sys.exit(1)
     
-    p = clock_vm.run('user:date -u', verbose=verbose, passio_popen=True)
+    p = clock_vm.run('user:date -u', verbose=verbose, passio_popen=True, ignore_stderr=True)
     date_out = p.stdout.read(100)
     date_out = date_out.strip()
     if not re.match(r'^[A-Za-z]* [A-Za-z]* [ 0-9][0-9] [0-9][0-9]:[0-9][0-9]:[0-9][0-9] [A-Z]* [0-9][0-9][0-9][0-9]$', date_out):