xenapi/agent: Change openssl error handling

Prior to this patch, if the openssl command returned a zero exit code
and wrote details to stderr, nova would raise a RuntimeError exception.
This patch changes the behavior to only raise a RuntimeError exception
when openssl returns a non-zero exit code. Regardless of the exit code
a warning will always be logged with stderr details if stderr is not
None. Note that processutils.execute will now raise a
processutils.ProcessExecutionError exception for any non-zero exit code
since we are passing check_exit_code=True, which we convert to a
Runtime error.

Thanks to Dimitri John Ledkov <xnox@ubuntu.com> and Eric Fried
<openstack@fried.cc> for helping with this patch.

Change-Id: I212ac2b5ccd93e00adb7b9fe102fcb70857c6073
Partial-Bug: #1771506
(cherry picked from commit 1da71fa4ab)

nova/tests/unit/virt/xenapi/test_agent.py

@@ -19,6 +19,7 @@ import time
 import mock
 from os_xenapi.client import host_agent
 from os_xenapi.client import XenAPI
+from oslo_concurrency import processutils
 from oslo_utils import uuidutils
 
 from nova import exception
@@ -311,6 +312,19 @@ class SetAdminPasswordTestCase(AgentTestCaseBase):
 
         mock_add_fault.assert_called_once_with(error, mock.ANY)
 
+    @mock.patch('oslo_concurrency.processutils.execute')
+    def test_run_ssl_successful(self, mock_execute):
+        mock_execute.return_value = ('0',
+            '*** WARNING : deprecated key derivation used.'
+            'Using -iter or -pbkdf2 would be better.')
+        agent.SimpleDH()._run_ssl('foo')
+
+    @mock.patch('oslo_concurrency.processutils.execute',
+                side_effect=processutils.ProcessExecutionError(
+                    exit_code=1, stderr=('ERROR: Something bad happened')))
+    def test_run_ssl_failure(self, mock_execute):
+        self.assertRaises(RuntimeError, agent.SimpleDH()._run_ssl, 'foo')
+
 
 class UpgradeRequiredTestCase(test.NoDBTestCase):
     def test_less_than(self):

nova/virt/xenapi/agent.py

@@ -422,11 +422,18 @@ class SimpleDH(object):
                'pass:%s' % self._shared, '-nosalt']
         if decrypt:
             cmd.append('-d')
-        out, err = processutils.execute(
-            *cmd, process_input=encodeutils.safe_encode(text))
-        if err:
-            raise RuntimeError(_('OpenSSL error: %s') % err)
-        return out
+        try:
+            out, err = processutils.execute(
+                *cmd,
+                process_input=encodeutils.safe_encode(text),
+                check_exit_code=True)
+            if err:
+                LOG.warning("OpenSSL stderr: %s", err)
+            return out
+        except processutils.ProcessExecutionError as e:
+            raise RuntimeError(
+                _('OpenSSL errored with exit code %(exit_code)d: %(stderr)s') %
+                 {'exit_code': e.exit_code, 'stderr': e.stderr})
 
     def encrypt(self, text):
         return self._run_ssl(text).strip('\n')