Re: [Qemu-devel] [PATCH] net: tap-linux: Fix unhelpful error message

[Luiz Capitulino <lcapitulino@redhat.com>]

On Fri, 14 Oct 2011 15:05:10 -0300
Luiz Capitulino <lcapitulino@redhat.com> wrote:

> I'm getting:
> 
>     could not configure /dev/net/tun (tap%d): Operation not permitted
> 
> When the ioctl() fails, ifr.ifr_name will most likely not be overwritten.
> So we better only use it when ifname contains a string.

I had forgotten about this one, but just got it again... Stefan, I think
this is a candidate for the trivial tree.

> 
> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
> ---
> 
> PS: Trivial tree candidate.
> 
>  net/tap-linux.c |    6 +++++-
>  1 files changed, 5 insertions(+), 1 deletions(-)
> 
> diff --git a/net/tap-linux.c b/net/tap-linux.c
> index ff8cad0..41d581b 100644
> --- a/net/tap-linux.c
> +++ b/net/tap-linux.c
> @@ -73,7 +73,11 @@ int tap_open(char *ifname, int ifname_size, int *vnet_hdr, int vnet_hdr_required
>          pstrcpy(ifr.ifr_name, IFNAMSIZ, "tap%d");
>      ret = ioctl(fd, TUNSETIFF, (void *) &ifr);
>      if (ret != 0) {
> -        error_report("could not configure %s (%s): %m", PATH_NET_TUN, ifr.ifr_name);
> +        if (ifname[0] != '\0') {
> +            error_report("could not configure %s (%s): %m", PATH_NET_TUN, ifr.ifr_name);
> +        } else {
> +            error_report("could not configure %s: %m", PATH_NET_TUN);
> +        }
>          close(fd);
>          return -1;
>      }