svn commit: r194262 - in head: include lib/libc/sys sys/compat/freebsd32 sys/kern tools/regression/file/closefrom

[John Baldwin]

On Monday 15 June 2009 4:49:38 pm Colin Percival wrote:
> John Baldwin wrote:
> >   One difference from other *BSD is that this closefrom() does not
> >   fail with any errors.  In practice, while the manpages for NetBSD and
> >   OpenBSD claim that they return EINTR, they ignore internal errors from
> >   close() and never return EINTR.  DFly does return EINTR, but for the common
> >   use case (closing fd's prior to execve()), the caller really wants all
> >   fd's closed and returning EINTR just forces callers to call closefrom() in
> >   a loop until it stops failing.
> 
> Wouldn't it be better for portability if closefrom(2) is defined to return an
> int, even if the value returned is always zero?  Otherwise people who want to
> write code which works on all BSDs end up having to do something like
> #ifdef __FreeBSD__
> 	closefrom(x);
> #else
> 	while (closefrom(x))
> 		continue;
> #endif

Solaris returns void, so we just end up in their #ifdef vs the other.  Also,
Robert's belief is that the vast majority of existing code doesn't do a loop
correctly, but instead just does a single call to closefrom(x).  In that
case, ignoring errors gives the best chance of working correctly.

-- 
John Baldwin