From b8cf990079d267d9e34fe03acaad515c623155e4 Mon Sep 17 00:00:00 2001
From: Wei Li <liwei@anbutu.com>
Date: Thu, 1 Feb 2018 18:56:04 +0800
Subject: [PATCH] qemu: clear persist flag on tap device

In the scenario which tap device was not created by qemu but passed
in(e.g, with some cni plugin), there was IFF_PERSIST flag set on it,
the flag need to be cleared to make sure tap device removed cleanly
on qemu exit.

(cherry picked from commit c3fbef2bb406e589c11286807ff6243687c8377a)
---
 hypervisor/qemu/network.go | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/hypervisor/qemu/network.go b/hypervisor/qemu/network.go
index dc58f425..5fa37d71 100644
--- a/hypervisor/qemu/network.go
+++ b/hypervisor/qemu/network.go
@@ -47,6 +47,11 @@ func GetTapFd(device, bridge, options string) (int, error) {
 		tapFile.Close()
 		return -1, fmt.Errorf("create tap device failed\n")
 	}
+	_, _, errno = syscall.Syscall(syscall.SYS_IOCTL, tapFile.Fd(), uintptr(syscall.TUNSETPERSIST), 0)
+	if errno != 0 {
+		tapFile.Close()
+		return -1, fmt.Errorf("clear tap device persist flag failed\n")
+	}
 
 	err = network.UpAndAddToBridge(device, bridge, options)
 	if err != nil {