storage: Don't allow encryption secretPath to be NULL

Allowing a NULL @secretPath for virStorageBackendCreateQemuImgCmdFromVol
would result in a generated command line with a dangling "file=" output.
So let's make sure the @secretPath exists before processing.

This means we should pass a dummy path from the storage test.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>
ACKed-by: NMichal Privoznik <mprivozn@redhat.com>

src/storage/storage_util.c

@@ -1233,6 +1233,11 @@ virStorageBackendCreateQemuImgCmdFromVol(virStoragePoolObjPtr pool,
 
     if (info.format == VIR_STORAGE_FILE_RAW && vol->target.encryption &&
         vol->target.encryption->format == VIR_STORAGE_ENCRYPTION_FORMAT_LUKS) {
+        if (!info.secretPath) {
+            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                           _("path to secret data file is required"));
+            goto error;
+        }
         if (virAsprintf(&info.secretAlias, "%s_encrypt0", vol->name) < 0)
             goto error;
         if (storageBackendCreateQemuImgSecretObject(cmd, info.secretPath,

tests/storagevolxml2argvtest.c

@@ -82,7 +82,7 @@ testCompareXMLToArgvFiles(bool shouldFail,
     cmd = virStorageBackendCreateQemuImgCmdFromVol(obj, vol,
                                                    inputvol, flags,
                                                    create_tool,
-                                                   NULL);
+                                                   "/path/to/secretFile");
     if (!cmd) {
         if (shouldFail) {
             virResetLastError();