linux-mips
[Top] [All Lists]

Re: pread and pwrite

To: Carsten Langgaard <carstenl@mips.com>
Subject: Re: pread and pwrite
From: "H. J. Lu" <hjl@lucon.org>
Date: Wed, 17 Jul 2002 12:01:08 -0700
Cc: Ralf Baechle <ralf@oss.sgi.com>, linux-mips@oss.sgi.com
In-reply-to: <3D357CA9.B847EDAC@mips.com>; from carstenl@mips.com on Wed, Jul 17, 2002 at 04:18:17PM +0200
References: <3D3532FB.E227A5AD@mips.com> <20020717155930.A25258@dea.linux-mips.net> <3D357CA9.B847EDAC@mips.com>
Sender: owner-linux-mips@oss.sgi.com
User-agent: Mutt/1.2.5.1i
On Wed, Jul 17, 2002 at 04:18:17PM +0200, Carsten Langgaard wrote:
> Ralf Baechle wrote:
> 
> > On Wed, Jul 17, 2002 at 11:03:55AM +0200, Carsten Langgaard wrote:
> >
> > >
> > > Here there is some checking for sane values and a proper error value is
> > > return.
> > > I guess this routine is replaced, if we have the syscall implemented
> > > with the sysdeps/unix/sysv/linux/mips/pread.c file.
> > > Here there is no check for sane values, is there any reason why ?
> > > The same thing goes for pwrite.
> >
> > The kernel does it's own error checking.  No need to duplicate that in
> > userspace.
> 
> The kernel doesn't do this a proper check then.
> The pread/pwrite parameters is also convert in glibc, the 'offset' is
> convert from a 'long' to a 'long long', but it isn't sign extended.
> So when pread is call with offset -1, then kernel won't see it as -1.
> 

Please check it out:

http://sources.redhat.com/ml/libc-alpha/2002-07/msg00188.html


H.J.


<Prev in Thread] Current Thread [Next in Thread>