Subject: Re: EISDIR on directory read(2)
To: None <>
From: der Mouse <mouse@Rodents.Montreal.QC.CA>
List: tech-kern
Date: 10/11/1999 02:53:57
> I'd like to go down on the record as disagreeing with returning
> EISDIR on directory read(2)

Me too, at least when the directory is local.

I'm really writing to respond to

> Locally, opendir(3) and readdir(3) are just magic wrappers around
> open(2) and read(2).

Are they?  I thought they were wrappers around getdents().  That's
certainly what the code in lib/libc/gen/ looks like to me.

> To me, as a programmer, this makes perfect sense.  getdents(2)
> *almost* strikes me as more of a hack than opendir(3) and readdir(3).
> Almost.

getdents is really necessary to present a uniform view of directory
entries across multiple filesystem types; userland code - even libc -
cannot be expected to know all about all possible directory formats,
especially remote ones on foreign OSes - VMS, for example.

> If you're going to return EISDIR, wouldn't you be doing that on the
> open(2), not the read(2)?

Yes...except that then we need a "open for fchdir/fstat/etc" method of
some sort.

> "If it ain't broke, don't fix it."


					der Mouse

		     7D C8 61 52 5D E7 2D 39  4E F1 31 3E E8 B3 27 4B