qemu: migration: Make check for empty hook XML robust

Also consider whitespace only strings returned from the hook as empty
result.

(cherry picked from commit 19b1ee42b49b2764f7df23787f4b6022886a612c)

diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
index 284cd5adbf1b03a46082ca1bfd864c0bd58dcec6..2a96661a01c85e628a31ed1a7adc3bead924438c 100644 (file)
--- a/src/qemu/qemu_migration.c
+++ b/src/qemu/qemu_migration.c
@@ -2570,7 +2570,7 @@ qemuMigrationPrepareAny(virQEMUDriverPtr driver,
         if (hookret < 0) {
             goto cleanup;
         } else if (hookret == 0) {
-            if (!*xmlout) {
+            if (virStringIsEmpty(xmlout)) {
                 VIR_DEBUG("Migrate hook filter returned nothing; using the"
                           " original XML");
             } else {