Re: [libvirt] [PATCH 4/5] virnetdevtap: add virNetDevTapGetName

This will be used on a tap file descriptor returned by the bridge helper to populate the <target> element, because the helper does not provide the interface name. Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com&gt; --- src/libvirt_private.syms | 1 + src/util/virnetdevtap.c | 33 +++++++++++++++++++++++++++++++++ src/util/virnetdevtap.h | 3 +++ 3 files changed, 37 insertions(+) diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms index f241ec4..06085ba 100644 --- a/src/libvirt_private.syms +++ b/src/libvirt_private.syms @@ -1515,6 +1515,7 @@ virNetDevOpenvswitchSetMigrateData; virNetDevTapCreate; virNetDevTapCreateInBridgePort; virNetDevTapDelete; +virNetDevTapGetName; # util/virnetdevveth.h diff --git a/src/util/virnetdevtap.c b/src/util/virnetdevtap.c index a884de1..e9fddf1 100644 --- a/src/util/virnetdevtap.c +++ b/src/util/virnetdevtap.c @@ -44,6 +44,39 @@ #define VIR_FROM_THIS VIR_FROM_NONE /** + * virNetDevTapGetName: + * @tapfd: a tun/tap file descriptor + * @ifname: a pointer that will receive the interface name + * + * Retrieve the interface name given a file descriptor for a tun/tap + * interface. + * + * Returns 0 if the interface name is successfully queried, -1 otherwise + */ +int +virNetDevTapGetName(int tapfd, char **ifname) +{ +#ifdef TUNGETIFF + struct ifreq ifr; + + /* The kernel will always return -1 at this point. + * If TUNGETIFF is not implemented then errno == EBADFD. + */ + if (ioctl(tapfd, TUNGETIFF, &ifr) < 0) { + virReportSystemError(errno, "%s", + _("Unable to query tap interface name")); + return -1; + } + + *ifname = strdup(ifr.ifr_name);

+ return 0; +#else + return -1; +#endif +} + + +/** * virNetDevProbeVnetHdr: * @tapfd: a tun/tap file descriptor * diff --git a/src/util/virnetdevtap.h b/src/util/virnetdevtap.h index 980db61..6bfc80c 100644 --- a/src/util/virnetdevtap.h +++ b/src/util/virnetdevtap.h @@ -35,6 +35,9 @@ int virNetDevTapCreate(char **ifname, int virNetDevTapDelete(const char *ifname) ATTRIBUTE_NONNULL(1) ATTRIBUTE_RETURN_CHECK; +int virNetDevTapGetName(int tapfd, char **ifname) + ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK; + typedef enum { VIR_NETDEV_TAP_CREATE_NONE = 0, /* Bring the interface up */