[Qemu-devel] [PATCH] fix network interface tap backend

[Christoph Egger <Christoph.Egger@amd.com>]

Fix network interface tap backend work on NetBSD.
It uses an ioctl to get the tap name.

 From Manuel Bouyer <bouyer@netbsd.org>
Signed-off-by: Christoph Egger <Christoph.Egger@amd.com>

diff --git a/net/tap-bsd.c b/net/tap-bsd.c
index 2f3efde..577aafe 100644
--- a/net/tap-bsd.c
+++ b/net/tap-bsd.c
@@ -28,6 +28,8 @@
  #include "qemu-error.h"

  #ifdef __NetBSD__
+#include <sys/ioctl.h>
+#include <net/if.h>
  #include <net/if_tap.h>
  #endif

@@ -40,8 +42,12 @@
  int tap_open(char *ifname, int ifname_size, int *vnet_hdr, int 
vnet_hdr_required)
  {
      int fd;
+#ifdef TAPGIFNAME
+    struct ifreq ifr;
+#else
      char *dev;
      struct stat s;
+#endif

  #if defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || 
defined(__OpenBSD__)
      /* if no ifname is given, always start the search from tap0/tun0. */
@@ -77,14 +83,30 @@ int tap_open(char *ifname, int ifname_size, int 
*vnet_hdr, int vnet_hdr_required
  #else
      TFR(fd = open("/dev/tap", O_RDWR));
      if (fd < 0) {
-        fprintf(stderr, "warning: could not open /dev/tap: no virtual 
network emulation\n");
+        fprintf(stderr,
+            "warning: could not open /dev/tap: no virtual network 
emulation: %s\n",
+            strerror(errno));
          return -1;
      }
  #endif

-    fstat(fd, &s);
+#ifdef TAPGIFNAME
+    if (ioctl(fd, TAPGIFNAME, (void *)&ifr) < 0) {
+        fprintf(stderr, "warning: could not get tap name: %s\n",
+            strerror(errno));
+        return -1;
+    }
+    pstrcpy(ifname, ifname_size, ifr.ifr_name);
+#else
+    if (fstat(fd, &s) < 0) {
+        fprintf(stderr,
+            "warning: could not stat /dev/tap: no virtual network 
emulation: %s\n",
+            strerror(errno));
+        return -1;
+    }
      dev = devname(s.st_rdev, S_IFCHR);
      pstrcpy(ifname, ifname_size, dev);
+#endif

      if (*vnet_hdr) {
          /* BSD doesn't have IFF_VNET_HDR */


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