svn commit: r273441 - in head/sys: kern sys

[Mateusz Guzik]

On Wed, Oct 22, 2014 at 10:51:31AM +0300, Konstantin Belousov wrote:
> On Wed, Oct 22, 2014 at 12:23:44AM +0000, Mateusz Guzik wrote:
> > Author: mjg
> > Date: Wed Oct 22 00:23:43 2014
> > New Revision: 273441
> > URL: https://svnweb.freebsd.org/changeset/base/273441
> > 
> > Log:
> >   filedesc: cleanup setugidsafety a little
> >   
> >   Rename it to fdsetugidsafety for consistency with other functions.
> >   
> >   There is no need to take filedesc lock if not closing any files.
> >   
> >   The loop has to verify each file and we are guaranteed fdtable has space
> >   for at least 20 fds. As such there is no need to check fd_lastfile.
> ^^^^^^^^^^^^^^^^^^^^^^^^ *
> 
[..]
> >  	fdp = td->td_proc->p_fd;
> >  	KASSERT(fdp->fd_refcnt == 1, ("the fdtable should not be shared"));
> > -	FILEDESC_XLOCK(fdp);
> > -	for (i = 0; i <= fdp->fd_lastfile; i++) {
> > -		if (i > 2)
> > -			break;
> > +	for (i = 0; i <= 2; i++) {
> [*] This requires an assert.
> 

I was considering adding one, but failed to come up with anything good.

Ideally we would compile-time assert that NDFILE is at least 3, but that
seems weirdly circumventable by sufficient accident.

MPASS(fdp->fd_nfiles > 3) does not guarantee we wont run into trouble,
has a potential to help.

Any suggestions?

-- 
Mateusz Guzik <mjguzik gmail.com>