libxl: add API wrapper for libxl_domain_create_restore

Upcoming changes will use different LIBXL_API_VERSION variants.

Prepare libxl_domain_create_restore, which got a new parameter
"send_back_fd" in Xen 4.7. libvirt does not use this parameter.

No functional change intended.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Reviewed-by: Jim Fehlig <jfehlig@suse.com>

src/libxl/libxl_api_wrapper.h

@@ -0,0 +1,44 @@
+/*
+ * libxl_api_wrapper.h: handle various libxl API variants
+ *
+ * Copyright (C) 2021 SUSE LLC
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <libxl.h>
+
+static inline int
+libxlDomainCreateRestoreWrapper(libxl_ctx *ctx,
+                                libxl_domain_config *d_config,
+                                uint32_t *domid,
+                                int restore_fd,
+                                const libxl_domain_restore_params *params,
+                                const libxl_asyncprogress_how *aop_console_how)
+{
+    int ret;
+
+#if LIBXL_API_VERSION < 0x040700
+    ret = libxl_domain_create_restore(ctx, d_config, domid, restore_fd, params,
+                                      NULL, aop_console_how);
+#else
+    ret = libxl_domain_create_restore(ctx, d_config, domid, restore_fd, -1,
+                                      params, NULL, aop_console_how);
+#endif
+
+    return ret;
+}

src/libxl/libxl_domain.c

@@ -22,6 +22,7 @@
 
 #include <fcntl.h>
 
+#include "libxl_api_wrapper.h"
 #include "libxl_domain.h"
 #include "libxl_capabilities.h"
 
@@ -1396,8 +1397,8 @@ libxlDomainStart(libxlDriverPrivatePtr driver,
 #ifdef LIBXL_HAVE_SRM_V2
         params.stream_version = restore_ver;
 #endif
-        ret = libxl_domain_create_restore(cfg->ctx, &d_config, &domid,
+        ret = libxlDomainCreateRestoreWrapper(cfg->ctx, &d_config, &domid,
-                                          restore_fd, &params, NULL,
+                                              restore_fd, &params,
                                           &aop_console_how);
         libxl_domain_restore_params_dispose(&params);
     }