qemu: restore: Fix restoring of VM when the restore hook returns empty XML

The documentation for the restore hook states that returning an empty
XML is equivalent with copying the input. There was a bug in the code
checking the returned string by checking the string instead of the
contents. Use the new helper to check if the string is empty.

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 009abc612a804f74647820a3db71df05272c49d0..d1f960007b36116e1bfbb32c619a74e1fe3a5ab5 100644 (file)
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -5831,7 +5831,7 @@ qemuDomainRestoreFlags(virConnectPtr conn,
                                    &xmlout)) < 0)
             goto cleanup;
 
-        if (hookret == 0 && xmlout) {
+        if (hookret == 0 && !virStringIsEmpty(xmlout)) {
             VIR_DEBUG("Using hook-filtered domain XML: %s", xmlout);
             hook_taint = true;
             newxml = xmlout;
@@ -6047,7 +6047,7 @@ qemuDomainObjRestore(virConnectPtr conn,
                                    NULL, xml, &xmlout)) < 0)
             goto cleanup;
 
-        if (hookret == 0 && xmlout) {
+        if (hookret == 0 && !virStringIsEmpty(xmlout)) {
             virDomainDefPtr tmp;
 
             VIR_DEBUG("Using hook-filtered domain XML: %s", xmlout);