On Sat, Feb 11, 2012 at 02:04:23AM -0500, Mouse wrote:
> I find myself wanting something I'm tentatively calling O_NOACCESS,
> which is basically "open for neither read nor write". (I want this
> mostly so I can open a --x directory for fchdir() purposes.)
>
> Looking at sys_open(), I see that one of the first checks it does is
>
> if ((flags & (FREAD | FWRITE)) == 0)
> return (EINVAL);
Not the least of your problems is that the user specifies one of
O_RDONLY, O_WRONLY or O_RDWR - which are 0, 1 and 2.
Makes it a little difficult to request 'no access'.
But I agree, an open(".", ???) in particular should work even when
you only have 'x' permissions so that you can fchdir() back later.
Possibly even open(".", O_RDONLY) shouls succeed - but not let
you perform any operations except fchdir() (and maybe openat()).
David
--
David Laight: da...@l8s.co.uk
