Re: pread and pwrite

[Carsten Langgaard <carstenl@mips.com>]

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.

>
>   Ralf

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