BSD tty security, part 4: What You Can Look Forward To

[Dan Bernstein]

In article <1991May1.201408.16204 at pcserver2.naitc.com> kdenning at genesis.Naitc.Com (Karl Denninger) writes:
> And I think I have a fix -- actually, two different
> fixes, both of which should be easily implemented.  Both ARE implemented on
> two different machines from different manufacturers here.
  [ 1. dynamic ptys, as on the RS/6000 ]

These are rather difficult to implement. They are an excellent long-term
solution, but it's much easier to apply my fixes to a typical BSD
machine than to radically reorganize and rewrite many parts of the
kernel for dynamic ttys.

  [ 2. something with O_EXCL on the MIPS ]

Um, O_EXCL does not have the semantics you describe on a standard BSD
machine, nor on any of the variants with which I'm familiar. MIPS may
have added something to have O_EXCL pay attention to reference counts,
but that solution simply won't work under SunOS or Ultrix or any similar
system. (Of course, with my TIOCOPENCT you can simulate the same thing.)

---Dan