Re: more fun with procfs (netfilter)

["H. Peter Anvin" <hpa@zytor.com>]

Followup to:  <Pine.GSO.4.21.0111190419250.17210-100000@weyl.math.psu.edu>
By author:    Alexander Viro <viro@math.psu.edu>
In newsgroup: linux.dev.kernel
> 
> Some shells (pdksh 5.2.14-1, bash 2.04 as shipped by SuSE) are trying to be
> smart if stdin is from regular file - they hope that third argument of
> lseek() is in bytes and is consistent with read() return value.
> 

Not just hope... they have a legitimate reason to expect that
guarantee from anything that advertises itself as S_IFREG.  I really
think procfs files should advertise themselves as S_IFCHR if they
can't fully obey the semantics of S_IFREG files (including having a
working length in stat()!)

Such S_IFCHR devices can return 0 in st_rdev to signal userspace that
this is a device node keyed by special filesystem semantics rather
than by device number.

	-hpa
-- 
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