Re: [libvirt] [PATCH v3 4/4] FreeBSD: implement virNetDevTapCreate() and virNetDevTapDelete().

5 Feb 2013

On 01/26/2013 08:13 AM, Roman Bogorodskiy wrote:
...
---
 src/util/virnetdevtap.c | 114 ++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 111 insertions(+), 3 deletions(-)

diff --git a/src/util/virnetdevtap.c b/src/util/virnetdevtap.c
index a884de1..36994fc 100644
--- a/src/util/virnetdevtap.c
+++ b/src/util/virnetdevtap.c
@@ -103,7 +103,7 @@ virNetDevProbeVnetHdr(int tapfd)
 #endif
-#ifdef TUNSETIFF
+#if defined(TUNSETIFF)
Pointless churn.
...
@@ -230,7 +230,115 @@ cleanup:
     VIR_FORCE_CLOSE(fd);
     return ret;
 }
-#else /* ! TUNSETIFF */
+#elif defined(__FreeBSD__)
Again, what is the REAL feature that we are probing here, instead of
hard-coding things to an OS probe?
...
+int virNetDevTapCreate(char **ifname,
+                       int *tapfd,
+                       unsigned int flags ATTRIBUTE_UNUSED)
+{
+    int s;
+    struct ifreq ifr;
+    int ret = -1;
+    char *newifname = NULL;
+
+    /* As FreeBSD determines interface type by name,
+     * we have to create 'tap' interface first and
+     * then rename it to 'vnet'
+     */
+    if ((s = virNetDevSetupControl("tap", &ifr)) < 0)
+        return -1;
+
+    if (ioctl(s, SIOCIFCREATE2, &ifr) < 0) {
Is the existence of SIOCIFCREATE2 the right feature to be probing for?
...
+        virReportSystemError(errno, "%s",
+                             _("Unable to create tap device"));
+        goto cleanup;
+    }
+
+    /* In case we were given exact interface name (e.g. 'vnetN'),
+     * we just rename to it. If we have format string like
+     * 'vnet%d', we need to find the first available name that
+     * matches this pattern
+     */
+    if (strstr(*ifname, "%d") != NULL) {
+        int i;
+        for (i = 0; i <= IF_MAXUNIT; i++) {
+            virBuffer newname = VIR_BUFFER_INITIALIZER;
+            virBufferAsprintf(&newname, *ifname, i);
+
+            if (virBufferError(&newname)) {
+                virBufferFreeAndReset(&newname);
+                virReportOOMError();
+                goto cleanup;
+            }
virBuffer is useful for concatenation.  But your use case is one-shot
formatting; in which case I'd use virAsprintf instead of virBufferAsprintf:

char *newname;
if (virAsprintf(&newname, *ifname, i) < 0) {
    virReportOOMError();
    goto cleanup;
}
...
+
+            if (virNetDevExists(virBufferCurrentContent(&newname)) == 0) {
+                newifname = strdup(virBufferContentAndReset(&newname));
+                break;
+            }
at which point, you don't have to strdup(); newname is already the right
allocated string.
...
+        }
+        if (newifname) {
+            VIR_FREE(*ifname);
+            *ifname = newifname;
+        } else {
+            virReportError(VIR_ERR_INTERNAL_ERROR,
+                           _("Failed to generate new name for interface %s"),
+                           ifr.ifr_name);
+            goto cleanup;
+        }
+    }
...
+
+int virNetDevTapDelete(const char *ifname)
int
virNetDevTapDelete(const char *ifname)
...
+
+#else /* !defined(__FreeBSD__) */
This comment isn't quite right; it is more like:

#else /* !TUNSETIFF && !__FreeBSD__ */

or whatever feature check we actually use.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

    