Re: [libvirt] [PATCH] lxc: Fix return value handlings of vethInterfaceUpOrDown and moveInterfaceToNetNs

On Sun, Jul 25, 2010 at 02:25:05AM +0900, Ryota Ozaki wrote: > On Sat, Jul 24, 2010 at 11:44 PM, Ryota Ozaki <ozaki.ryota(a)gmail.com&gt; wrote: > > Hi Laine, > > > > On Sat, Jul 24, 2010 at 2:58 AM, Laine Stump <laine(a)laine.org&gt; wrote: > >>  On 07/23/2010 01:25 PM, Ryota Ozaki wrote: > >>> > >>> Both may return a positive value when they fail. We should check > >>> if the value is not zero instead of checking if it's negative. > >> > >> I notice that  lxcSetupInterfaces has a comment saying that it returns -1 on > >> failure, but it actually just passes on what is returned by > >> vethInterfaceUpOrDown. > > > > Oh, I didn't know that. > > > > Additionally, I found that other functions, e.g., setMacAddr, are also handled > > with the wrong way. And also handling return values with virReportSystemError > > is also wrong because it expects an errno, not an exit code. We have to fix > > all of them ;-< > > > >> > >> Would you be willing to consider instead just changing vethInterfaceUpOrDown > >> and moveInterfaceToNetNs to return -1 in all error cases (and checking the > >> return for < 0), rather than grabbing the exit code of the exec'ed command? > >> None of the callers do anything with that extra information anyway, and it > >> would help to make the return values more consistent (which makes it easier > >> to catch bugs like this, or eliminates them altogether ;-) > > > > Yeah, I'm also a bit annoying with the return values. Hmm, but we now show error > > messages with the return values outside the functions. Without that, we have to > > show the error message in the functions or some other place, otherwise we lose > > useful information of errors. It seems not good idea. > > > > One option is to let virRun show an error message by passing NULL to the second > > argument (status) of it, like brSetEnableSTP in util/bridge.c, and > > always return -1 > > on a failure. It'd satisfy what you suggest. > > > > Honestly said, I cannot decide. Anyone has any suggestions on that? You could just change   return cmdResult to   return -cmdResult; That would still let you give the error code, while also keeping the value < 0

Daniel -- |: Red Hat, Engineering, London    -o-   http://people.redhat.com/berrange/ :| |: http://libvirt.org -o- http://virt-manager.org -o- http://deltacloud.org :| |: http://autobuild.org        -o-         http://search.cpan.org/~danberr/ :| |: GnuPG: 7D3B9505  -o-   F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|