Michael Tokarev <m...@tls.msk.ru> writes:
> In net/tap-linux.c, when manipulation of /dev/net/tun fails, it prints
> (with fprintf) something like this:
>
> warning: could not open /dev/net/tun: no virtual network emulation
>
> this has 2 issues:
> 1) it is not a warning really, it's a fatal error (kvm exits after that),
> 2) there's no indication as of what's actually wrong: printing errno there
> is helpful.
>
> The patch below removes the "warning" prefix, uses %m (since it's linux,
> %m is available as format modifier), and changes fprintf() to qemu_error().
> Now it prints something like this instead:
>
> could not configure /dev/net/tun: Device or resource busy
>
> (there are 2 messages like that in the same function)
>
> This fixes Debian bug #578154, see
> http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=578154
>
> Signed-Off-By: Michael Tokarev <m...@tls.msk.ru>
>
> diff --git a/net/tap-linux.c b/net/tap-linux.c
> index 6af9e82..dbcbe6f 100644
> --- a/net/tap-linux.c
> +++ b/net/tap-linux.c
> @@ -39,7 +39,7 @@ int tap_open(char *ifname, int ifname_size, int *vnet_hdr,
> int vnet_hdr_required
>
> TFR(fd = open("/dev/net/tun", O_RDWR));
> if (fd < 0) {
> - fprintf(stderr, "warning: could not open /dev/net/tun: no virtual
> network emulation\n");
> + qemu_error("could not open /dev/net/tun: %m\n");
> return -1;
> }
> memset(&ifr, 0, sizeof(ifr));
This might apply to the stable branch (I haven't tried), but I don't
think it works on master. There, it should look like this (untested):
+ error_report("could not open /dev/net/tun: %m");
[...]
