[libvirt] [PATCH] Fix vlan ID detection in udev interface driver

[Michal Privoznik]

On 24.04.2014 15:19, Ján Tomko wrote:
> Instead of guessing it from the interface name, look into
> /proc/net/vlan/<interface>.
>
> This works for devices not named <real_device>.<vlan ID>,
> avoiding an error flood when virt-manager keeps asking about
> them every second:
>
> https://bugzilla.redhat.com/show_bug.cgi?id=966329
> ---
>   src/interface/interface_backend_udev.c | 67 ++++++++++++++++++++++++++--------
>   1 file changed, 51 insertions(+), 16 deletions(-)
>
> diff --git a/src/interface/interface_backend_udev.c b/src/interface/interface_backend_udev.c
> index b05ac0e..bec8c45 100644
> --- a/src/interface/interface_backend_udev.c
> +++ b/src/interface/interface_backend_udev.c
> @@ -20,11 +20,13 @@
>    */
>   #include <config.h>
>
> +#include <ctype.h>
>   #include <errno.h>
>   #include <dirent.h>
>   #include <libudev.h>
>
>   #include "virerror.h"
> +#include "virfile.h"
>   #include "c-ctype.h"
>   #include "datatypes.h"
>   #include "domain_conf.h"
> @@ -966,31 +968,64 @@ udevGetIfaceDefVlan(struct udev *udev ATTRIBUTE_UNUSED,
>                       const char *name,
>                       virInterfaceDef *ifacedef)
>   {
> -    const char *vid;
> +    char *procpath = NULL;
> +    char *buf = NULL;
> +    char *vid_pos, *dev_pos;
> +    size_t vid_len, dev_len;
> +    const char *vid_prefix = "VID: ";
> +    const char *dev_prefix = "\nDevice: ";
> +    int ret = -1;
> +
> +    if (virAsprintf(&procpath, "/proc/net/vlan/%s", name) < 0)
> +        goto cleanup;
> +
> +    if (virFileReadAll(procpath, BUFSIZ, &buf) < 0)
> +        goto cleanup;
>
> -    /* Find the DEVICE.VID again */
> -    vid = strrchr(name, '.');
> -    if (!vid) {
> +    if ((vid_pos = strstr(buf, vid_prefix)) == NULL) {
>           virReportError(VIR_ERR_INTERNAL_ERROR,
>                          _("failed to find the VID for the VLAN device '%s'"),
>                          name);
> -        return -1;
> +        goto cleanup;
>       }
> +    vid_pos += strlen(vid_prefix);
>
> -    /* Set the VLAN specifics */
> -    if (VIR_STRDUP(ifacedef->data.vlan.tag, vid + 1) < 0)
> -        goto error;
> -    if (VIR_STRNDUP(ifacedef->data.vlan.devname,
> -                    name, (vid - name)) < 0)
> -        goto error;
> +    if ((vid_len = strspn(vid_pos, "0123456789")) == 0 ||
> +        !isspace(vid_pos[vid_len])) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR,
> +                       _("failed to find the VID for the VLAN device '%s'"),
> +                       name);
> +        goto cleanup;
> +    }
>
> -    return 0;
> +    if ((dev_pos = strstr(vid_pos + vid_len, dev_prefix)) == NULL) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR,
> +                       _("failed to find the real device for the VLAN device '%s'"),
> +                       name);
> +        goto cleanup;
> +    }
> +    dev_pos += strlen(dev_prefix);
>
> - error:
> -    VIR_FREE(ifacedef->data.vlan.tag);
> -    VIR_FREE(ifacedef->data.vlan.devname);
> +    if ((dev_len = strcspn(dev_pos, "\n")) == 0) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR,
> +                       _("failed to find the real device for the VLAN device '%s'"),
> +                       name);
> +        goto cleanup;
> +    }
>
> -    return -1;
> +    if (VIR_STRNDUP(ifacedef->data.vlan.tag, vid_pos, vid_len) < 0)
> +        goto cleanup;
> +    if (VIR_STRNDUP(ifacedef->data.vlan.devname, dev_pos, dev_len) < 0) {
> +        VIR_FREE(ifacedef->data.vlan.tag);
> +        goto cleanup;
> +    }
> +
> +    ret = 0;
> +
> + cleanup:
> +    VIR_FREE(procpath);
> +    VIR_FREE(buf);
> +    return ret;
>   }
>
>   static virInterfaceDef * ATTRIBUTE_NONNULL(1)
>

ACK, but I'm not sure if this qualifies as the release material.

Michal