Date: Mon, 27 Feb 2006 13:20:30 +0300 From: Yar Tikhiy <yar@comp.chem.msu.su> To: Gleb Smirnoff <glebius@FreeBSD.org> Cc: arch@FreeBSD.org, Andre Oppermann <andre@FreeBSD.org>, jlemon@FreeBSD.org Subject: Re: changing EINVAL for SIOCSIFCAP to something else Message-ID: <20060227102029.GK6435@comp.chem.msu.su> In-Reply-To: <20060227100031.GY55275@cell.sick.ru> References: <20060227083815.GW55275@cell.sick.ru> <20060227091417.GF6435@comp.chem.msu.su> <20060227083815.GW55275@cell.sick.ru> <4402C09C.C3FB0064@freebsd.org> <20060227093431.GX55275@cell.sick.ru> <20060227094458.GH6435@comp.chem.msu.su> <20060227100031.GY55275@cell.sick.ru>
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On Mon, Feb 27, 2006 at 01:00:31PM +0300, Gleb Smirnoff wrote: > On Mon, Feb 27, 2006 at 12:44:58PM +0300, Yar Tikhiy wrote: > Y> > On Mon, Feb 27, 2006 at 10:04:28AM +0100, Andre Oppermann wrote: > Y> > A> > I prefer this variant: > Y> > A> > > Y> > A> > if (ifp->if_ioctl == NULL) > Y> > A> > return (ENOTTY); > Y> > A> > if (ifr->ifr_reqcap & ~ifp->if_capabilities) > Y> > A> > return (ENODEV); > Y> > A> > > Y> > A> > Any objections? > Y> [...] > Y> > Y> I'm afraid that this is a case when EINVAL is used properly: an > Y> > Y> argument to ioctl doesn't make sense to a particular device. It's > Y> > Y> true that EINVAL may be abused in other places though. I wish each > Y> > Y> EINVAL being returned to the userland were accompanied by log(). > Y> > > Y> > I don't agree. EINVAL can logically fit to almost any error condition. We > Y> > should fine error codes fitting better. If "ioctl doesn't make sense to a > Y> > particular device", then we should say "Operation not supported by device", > Y> > which is ENODEV. > Y> > Y> You see, it isn't ioctl itself that doesn't make sense to the device, > Y> it's a single argument, ifr_reqcap. That was my point. Of course, > > Yes. The ioctl is correct, that's why we do not return ENOTTY. The > argument is correct, that's why we do not return EINVAL. The argument > is not applicable to this device, that's why I suggest to use ENODEV. This interpretation sounds fair to me. Did you look at other cases when ENODEV was returned? How consistent were they with this one? > Y> I won't insist on it because the traditional errno is getting very > Y> limited under the present conditions anyway. -- Yar
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