8 Aug
2019
8 Aug
'19
3:33 a.m.
On Tue, 6 Aug 2019, Lyndon Nerenberg wrote:
Hmmm... I have this vague memory of V5 (which I only used for a couple of
months before we got V6) not clearing that bit, but after all these years
my memory is starting to fail me :-(
Just to extend
this thread a bit more, when did the set[ug]id bit start
getting turned off if the file was overwritten?
I'm pretty sure that's been the case since the dawn of time. It was certainly the case in every System V (release 0
and beyond) I
worked with, along with many BSDs derivatives (SunOS 3+, Ultrix, etc).
(And Xenix, which had it's own insanity that I now think selinux is
trying to inflict on me.)
I've always thought that Xenix was insane to start with... Then again, my
first experience with it was on a 286... Now, when porting Unify, should
I use large memory model here or small memory model? Crazy.
This has been documented in chown(2) for as long as I
can remember, so
that's a good place to start if you want to dig back through the various
source trees.
I don't have access to the sources right now, but I'll take your word for
it; it was just a passing thought.
-- Dave
8 Aug
8 Aug
12:39 p.m.
New subject: Set-uid shell scripts
On 2019-Aug-08 07:33:47 +1000, Dave Horsfall <dave(a)horsfall.org> wrote:
I've always thought that Xenix was insane to start
with... Then again, my
first experience with it was on a 286... Now, when porting Unify, should
I use large memory model here or small memory model? Crazy.
Ah, yes. I remember it well. The large, small and various mixed modes
were a consequence of the braindeadedness of the 286 - reloading segment
registers (pretty much every memory reference in large mode) was abysmally
slow. I recall hacking mg (a cut-down emacs clone) so that buffers were
in "far" memory and everything else was "near".
Some of the Xenix features I recall were:
* occasionally fork() would return -1 in both the parent and child (or
something like that - it would both succeed and report failure)
* The contents of comments would affect the Pascal compiler's ability
to compile the program (this was "using uninitialised variables"
behaviour, rather than magic lint-style comments). It made software
development "interesting" because checking a program into SCCS might
stop it compiling.
* fork()ing a large process could panic the system.
* The C compiler barfed on parts of starchart (from comp.sources.???)
--
Peter Jeremy
1964
days inactive
1965
days old
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