[libvirt] [PATCH] Revert "utils: Remove the logging of errors from virNetDevSendEthtoolIoctl"

[John Ferlan]

On 11/03/2015 09:17 AM, Daniel P. Berrange wrote:
> This reverts commit 6f2a0198e913c91a2ef8b99db79b7d3cc5396957.
> 
> This commit removed error reporting from virNetDevSendEthtoolIoctl
> pushing responsibility onto the callers. This is wrong, however,
> since virNetDevSendEthtoolIoctl calls virNetDevSetupControl
> which can still report errors. So as a result virNetDevSendEthtoolIoctl
> may or may not report errors depending on which bit of it fails, and as
> a result callers now overwrite some errors.
> 
> It also introduced a regression causing unprivileged libvirtd to
> spew error messages to the console due to inability to query the
> NIC features, an error which was previously ignored.
> 
> virNetDevSetupControlFull:148 : Cannot open network interface control socket: Operation not permitted
> virNetDevFeatureAvailable:3062 : Cannot get device wlp3s0 flags: Operation not permitted
> virNetDevSetupControlFull:148 : Cannot open network interface control socket: Operation not permitted
> virNetDevFeatureAvailable:3062 : Cannot get device wlp3s0 flags: Operation not permitted
> virNetDevSetupControlFull:148 : Cannot open network interface control socket: Operation not permitted
> virNetDevFeatureAvailable:3062 : Cannot get device wlp3s0 flags: Operation not permitted
> virNetDevSetupControlFull:148 : Cannot open network interface control socket: Operation not permitted
> virNetDevFeatureAvailable:3062 : Cannot get device wlp3s0 flags: Operation not permitted
> 
> Looking back at the original posting I see no explanation of why
> thsi refactoring was needed, so reverting the clearly broken
> error reporting logic looks like the best option.

A bit of history...

Going back through the timeline...  Moshe Levi proposes patches to add
support for new feature/bits:

http://www.redhat.com/archives/libvir-list/2015-June/msg00921.html

reviewed and posted v2 in July:

http://www.redhat.com/archives/libvir-list/2015-July/msg00548.html

Changes get pushed; however, they lead to an issue:

http://www.redhat.com/archives/libvir-list/2015-August/msg00162.html

Moshe provided a patch to resolve that:

http://www.redhat.com/archives/libvir-list/2015-August/msg00263.html

Laine has a different proposal:

http://www.redhat.com/archives/libvir-list/2015-August/msg00382.html

which after review gets shortened a bit:

http://www.redhat.com/archives/libvir-list/2015-August/msg00471.html

and pushed

Moshe as an update to his v1 msg00263

http://www.redhat.com/archives/libvir-list/2015-August/msg00567.html

Comments from there lead to posting changes just for the ioctl errors:

http://www.redhat.com/archives/libvir-list/2015-August/msg00625.html

Which leads to the v2 of that series (which you're proposing to revert):

http://www.redhat.com/archives/libvir-list/2015-August/msg00720.html


I suppose when I reviewed I just saw using virNetDevSetupControl as way
to use existing functions as opposed to calling socket() directly. It
was something different between v2 and v1 of that change, but other than
the additional virSetInherit call - it was essentially the same.

Even with the revert, in the unpriv'd libvirt, wouldn't the error:

    virReportSystemError(errno, "%s", _("Cannot open control socket"));

still still be spewed? Since virNetDevSetupControlFull:148 is the socket
call failure and not the ioctl failure. Sure the caller wouldn't spew a
second one, but why would the first one not be spewed?

Seems another option would be to add a "!virGetLastError()" prior to the
virReportSystemError in the callers (at least to avoid the two error
messages. Although there was a exchange between Martin and Moshe about that.

The whole reason for the removal of the switch on ioctl() failure was
detailed in one of the responses to the link above.  It wasn't clear why
we would filter on certain errno values, although I suppose the unpriv'd
libvirt path makes it more understandable. Still the socket() call
failure path would be hit first.



John

> 
> Signed-off-by: Daniel P. Berrange <berrange at redhat.com>
> ---
>  src/util/virnetdev.c | 56 +++++++++++++++++++++++++++++++++++++---------------
>  1 file changed, 40 insertions(+), 16 deletions(-)
> 
> diff --git a/src/util/virnetdev.c b/src/util/virnetdev.c
> index 9789e93..657df3a 100644
> --- a/src/util/virnetdev.c
> +++ b/src/util/virnetdev.c
> @@ -3145,15 +3145,39 @@ static int
>  virNetDevSendEthtoolIoctl(const char *ifname, void *cmd)
>  {
>      int ret = -1;
> -    int fd;
> -    struct ifreq ifr;
> +    int sock = -1;
> +    virIfreq ifr;
>  
> -    if ((fd = virNetDevSetupControl(ifname, &ifr)) < 0)
> -        return ret;
> +    sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
> +    if (sock < 0) {
> +        virReportSystemError(errno, "%s", _("Cannot open control socket"));
> +        goto cleanup;
> +    }
> +
> +    memset(&ifr, 0, sizeof(ifr));
> +    strcpy(ifr.ifr_name, ifname);
>      ifr.ifr_data = cmd;
> -    ret = ioctl(fd, SIOCETHTOOL, &ifr);
> +    ret = ioctl(sock, SIOCETHTOOL, &ifr);
> +    if (ret != 0) {
> +        switch (errno) {
> +            case EPERM:
> +                VIR_DEBUG("ethtool ioctl: permission denied");
> +                break;
> +            case EINVAL:
> +                VIR_DEBUG("ethtool ioctl: invalid request");
> +                break;
> +            case EOPNOTSUPP:
> +                VIR_DEBUG("ethtool ioctl: request not supported");
> +                break;
> +            default:
> +                virReportSystemError(errno, "%s", _("ethtool ioctl error"));
> +                goto cleanup;
> +        }
> +    }
>  
> -    VIR_FORCE_CLOSE(fd);
> + cleanup:
> +    if (sock)
> +        VIR_FORCE_CLOSE(sock);
>      return ret;
>  }
>  
> @@ -3170,12 +3194,12 @@ virNetDevSendEthtoolIoctl(const char *ifname, void *cmd)
>  static int
>  virNetDevFeatureAvailable(const char *ifname, struct ethtool_value *cmd)
>  {
> +    int ret = -1;
> +
>      cmd = (void*)cmd;
> -    if (virNetDevSendEthtoolIoctl(ifname, cmd) < 0) {
> -        virReportSystemError(errno, _("Cannot get device %s flags"), ifname);
> -        return -1;
> -    }
> -    return cmd->data > 0 ? 1 : 0;
> +    if (!virNetDevSendEthtoolIoctl(ifname, cmd))
> +        ret = cmd->data > 0 ? 1 : 0;
> +    return ret;
>  }
>  
>  
> @@ -3192,12 +3216,12 @@ virNetDevFeatureAvailable(const char *ifname, struct ethtool_value *cmd)
>  static int
>  virNetDevGFeatureAvailable(const char *ifname, struct ethtool_gfeatures *cmd)
>  {
> +    int ret = -1;
> +
>      cmd = (void*)cmd;
> -    if (virNetDevSendEthtoolIoctl(ifname, cmd) < 0) {
> -        virReportSystemError(errno, _("Cannot get device %s generic features"), ifname);
> -        return -1;
> -    }
> -    return FEATURE_BIT_IS_SET(cmd->features, TX_UDP_TNL, active);
> +    if (!virNetDevSendEthtoolIoctl(ifname, cmd))
> +        ret = FEATURE_BIT_IS_SET(cmd->features, TX_UDP_TNL, active);
> +    return ret;
>  }
>  # endif
>  
>