vircgroup: extract virCgroupV1StealPlacement

Reviewed-by: NFabiano Fidêncio <fidencio@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

src/util/vircgroup.c

@@ -1319,8 +1319,7 @@ virCgroupNewMachineSystemd(const char *name,
                            &init) < 0)
         return -1;
 
-    path = init->controllers[VIR_CGROUP_CONTROLLER_SYSTEMD].placement;
-    init->controllers[VIR_CGROUP_CONTROLLER_SYSTEMD].placement = NULL;
+    path = init->backend->stealPlacement(init);
     virCgroupFree(&init);
 
     if (!path || STREQ(path, "/") || path[0] != '/') {

src/util/vircgroupbackend.h

@@ -66,6 +66,9 @@ typedef int
 (*virCgroupValidatePlacementCB)(virCgroupPtr group,
                                 pid_t pid);
 
+typedef char *
+(*virCgroupStealPlacementCB)(virCgroupPtr group);
+
 struct _virCgroupBackend {
     virCgroupBackendType type;
 
@@ -77,6 +80,7 @@ struct _virCgroupBackend {
     virCgroupDetectMountsCB detectMounts;
     virCgroupDetectPlacementCB detectPlacement;
     virCgroupValidatePlacementCB validatePlacement;
+    virCgroupStealPlacementCB stealPlacement;
 };
 typedef struct _virCgroupBackend virCgroupBackend;
 typedef virCgroupBackend *virCgroupBackendPtr;

src/util/vircgroupv1.c

@@ -402,6 +402,17 @@ virCgroupV1ValidatePlacement(virCgroupPtr group,
 }
 
 
+static char *
+virCgroupV1StealPlacement(virCgroupPtr group)
+{
+    char *ret = NULL;
+
+    VIR_STEAL_PTR(ret, group->controllers[VIR_CGROUP_CONTROLLER_SYSTEMD].placement);
+
+    return ret;
+}
+
+
 virCgroupBackend virCgroupV1Backend = {
     .type = VIR_CGROUP_BACKEND_TYPE_V1,
 
@@ -412,6 +423,7 @@ virCgroupBackend virCgroupV1Backend = {
     .detectMounts = virCgroupV1DetectMounts,
     .detectPlacement = virCgroupV1DetectPlacement,
     .validatePlacement = virCgroupV1ValidatePlacement,
+    .stealPlacement = virCgroupV1StealPlacement,
 };