pidfile_open incorrectly returns EAGAIN when pidfile is locked

[Pawel Jakub Dawidek]

On Thu, Mar 14, 2013 at 09:42:40AM -0400, John Baldwin wrote:
> On Thursday, March 14, 2013 4:44:20 am Pawel Jakub Dawidek wrote:
> > On Thu, Mar 14, 2013 at 08:28:25AM +0100, Dirk Engling wrote:
> > > -----BEGIN PGP SIGNED MESSAGE-----
> > > Hash: SHA1
> > > 
> > > On 13.03.13 23:08, Pawel Jakub Dawidek wrote:
> > > 
> > > > I think I considered something similar at first, but the change I 
> > > > proposed was optimal, IMHO at the cost of producing pretty large
> > > > diff, because of indentation change. But to be sure, can you send a
> > > > patch of your proposed change?
> > > 
> > > http://erdgeist.org/arts/software/Code/pidfile.c.diff
> > 
> > Right. Your patch assumes EWOULDBLOCK is equal to EAGAIN, which is true
> > on FreeBSD, but is not portable. Also in case pidptr is NULL you compare
> > errno three times instead of just one (not a big deal of course, just
> > something that could be done a bit more optimal:)).
> 
> Geeze, why not just add an else.  That's the really short diff:

Heh, I did consider that as well, but here you check errno twice,
instead of once. Guys, is there anything wrong with the patch I
proposed?

> Index: pidfile.c
> ===================================================================
> --- pidfile.c	(revision 248162)
> +++ pidfile.c	(working copy)
> @@ -140,7 +140,8 @@ pidfile_open(const char *path, mode_t mode, pid_t
>  				*pidptr = -1;
>  			if (errno == 0 || errno == EAGAIN)
>  				errno = EEXIST;
> -		}
> +		} else if (errno == EWOULDBLOCK)
> +			errno = EEXIST;
>  		free(pfh);
>  		return (NULL);
>  	}

-- 
Pawel Jakub Dawidek                       http://www.wheelsystems.com
FreeBSD committer                         http://www.FreeBSD.org
Am I Evil? Yes, I Am!                     http://tupytaj.pl
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