Re: [libvirt] [PATCH 07/10] libxl: prevent attaching multiple netdevs with the same MAC

Marek Marczykowski-Górecki wrote: > On Thu, Feb 19, 2015 at 11:43:15AM -0700, Jim Fehlig wrote: > >> Marek Marczykowski-Górecki wrote: >> >>> It will not be possible to detach such device later. Also improve >>> logging in such cases. >>> >>> Signed-off-by: Marek Marczykowski-Górecki <marmarek(a)invisiblethingslab.com&gt; >>> --- >>> src/libxl/libxl_driver.c | 41 +++++++++++++++++++++++++++++++++++++++-- >>> 1 file changed, 39 insertions(+), 2 deletions(-) >>> >>> diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c >>> index ce3a99b..005cc96 100644 >>> --- a/src/libxl/libxl_driver.c >>> +++ b/src/libxl/libxl_driver.c >>> @@ -2787,6 +2787,7 @@ libxlDomainAttachNetDevice(libxlDriverPrivatePtr driver, >>> int actualType; >>> libxl_device_nic nic; >>> int ret = -1; >>> + char mac[VIR_MAC_STRING_BUFLEN]; >>> >>> /* preallocate new slot for device */ >>> if (VIR_REALLOC_N(vm->def->nets, vm->def->nnets + 1) < 0) >>> @@ -2801,6 +2802,14 @@ libxlDomainAttachNetDevice(libxlDriverPrivatePtr driver, >>> >>> actualType = virDomainNetGetActualType(net); >>> >>> + /* -2 means "multiple matches" so then fail also */ >>> >>> >> No longer true after commit 2fbae1b2. I think you just want to check if >> virDomainNetFindIdx() >= 0, meaning the def already contains a net >> device with the same mac address. >> > > But here the error is when the device *is* found, so the opposite case > than already reported as an error by virDomainNetFindIdx. If you find an idx >= 0, then the domain def already contains a net device with the same mac address, right? In that case, you report an error and return failure from libxlDomainAttachNetDevice().