Re: [PATCH] Drop O_LARGEFILE from F_GETFL for POSIX compliance

[Andi Kleen <ak@suse.de>]

On Sun, 21 Mar 2004 21:39:44 -0800
Andrew Morton <akpm@osdl.org> wrote:

> Andi Kleen <ak@suse.de> wrote:
> >
> > 
> > On 64bit architectures open() sets O_LARGEFILE implicitely. This causes the LSB
> > testsuite to fail, which checks that F_GETFL only returns the flags set by 
> > a previous open.
> > 
> > According to the POSIX standards gurus the Linux behaviour is not compliant.
> > 
> > This patch fixes this by just not reporting O_LARGEFILE in F_GETFL.
> > 
> > This has been in several shipping SuSE releases and the x86-64.org CVS
> > treee for a long time, so is unlikely to break anything.
> > 
> > -Andi
> > 
> > diff -burpN -X ../KDIFX linux-2.4.26-pre5/fs/fcntl.c linux-merge/fs/fcntl.c
> > --- linux-2.4.26-pre5/fs/fcntl.c	2004-01-13 10:29:17.000000000 +0100
> > +++ linux-merge/fs/fcntl.c	2003-10-23 15:40:52.000000000 +0200
> > @@ -271,7 +271,7 @@ static long do_fcntl(unsigned int fd, un
> >  			set_close_on_exec(fd, arg&1);
> >  			break;
> >  		case F_GETFL:
> > -			err = filp->f_flags;
> > +			err = filp->f_flags & ~O_LARGEFILE;
> >  			break;
> >  		case F_SETFL:
> >  			lock_kernel();
> 
> eh?   If the application on a 64-bit box does
> 
> 	open("foo", O_LARGEFILE|O_RDWR);
> 
> then a subsequent F_GETFL will now return just O_RDWR, will it not?  So
> it's still posixly incorrect?

No, because O_LARGEFILE is not part of POSIX :-) (they use open64 etc.)


> I think open() needs to set O_KERNEL_LARGEFILE, and we mask that off in
> F_GETFL, and test for (O_LARGEFILE|O_KERNEL_LARGEFILE) everywhere.


That would be the best solution, agreed But it would be a lot more intrusive
because all file systems need to be audited and fixed.

-Andi