Re: [libvirt] PATCH: Fix passing of ifname to QEMU
"Daniel P. Berrange" <berrange(a)redhat.com> wrote:
When using the type='ethernet' network device configuration
for a guest
we pass a script, and optional interface name to QEMU. If ifname is
omitted, then QEMU allocates one itself. The problem was we were passing
an ifname of '(null)' by mistake. This patch corrects that problem and
adds a test for it.
Daniel
diff -r b6a065030fa6 src/qemu_conf.c
--- a/src/qemu_conf.c Fri Jan 30 12:28:00 2009 +0000
+++ b/src/qemu_conf.c Fri Jan 30 13:07:11 2009 +0000
@@ -1147,11 +1147,18 @@ int qemudBuildCommandLine(virConnectPtr
case VIR_DOMAIN_NET_TYPE_ETHERNET:
{
char arg[PATH_MAX];
- if (snprintf(arg, PATH_MAX-1,
"tap,ifname=%s,script=%s,vlan=%d",
- net->ifname,
- net->data.ethernet.script,
- vlan) >= (PATH_MAX-1))
- goto error;
+ if (net->ifname) {
+ if (snprintf(arg, PATH_MAX-1,
"tap,ifname=%s,script=%s,vlan=%d",
+ net->ifname,
+ net->data.ethernet.script,
+ vlan) >= (PATH_MAX-1))
+ goto error;
+ } else {
+ if (snprintf(arg, PATH_MAX-1,
"tap,script=%s,vlan=%d",
+ net->data.ethernet.script,
+ vlan) >= (PATH_MAX-1))
+ goto error;
+ }
Along the way, it'd be nice to use "sizeof(arg)-1" in place of
PATH_MAX-1.
That format string and arg list are long enough
that it'd be good not to duplicate them.
How about this instead?
char if_buf[PATH_MAX];
if_buf[0] = 0;
if (net->ifname
&& (snprintf(if_buf, sizeof(if_buf), ",script=%s",
ifname)
= sizeof(if_buf)-1))
goto error;
if (snprintf(arg, sizeof(arg), "tap%s,script=%s,vlan=%d",
if_buf,
net->data.ethernet.script,
vlan) >= sizeof(arg)-1))
goto error;
+1 for the test
ACK either way.