kern/120869: [procfs] 'stat' shows that all files have 0-length when they are actually not empty

[Bruce Evans]

On Thu, 21 Feb 2008, Robert Watson wrote:

> On Thu, 21 Feb 2008, Bruce Evans wrote:
>>> [about files in procfs]
>> The bug is mainly that stat() claims that the files are regular when they 
>> highly irregular (they are more like fifos).  This confuses naive 
>> applications into thinking that normal access methods for regular files 
>> actually work.
>
> I feel this way more generally about synthetic file systems with objects in 
> them that don't correspond with any of the standard file system objects that 
> applications known how to deal with.

Enough to break compatibility/portabiility by adding a new file type? :-)
S_IFMT has 4 bits, so it could encode 16 file types, but it currently only
encodes 8.  It looks like it once had only 3 bits but was expanded for
fifos.  It was last changed in ~1993 in 4.4BSD to add whiteouts.

Bruce