Trojan Horses

Steve Nuchia steve at nuchat.UUCP
Fri Oct 19 00:36:34 AEST 1990


In article <BZS.90Oct17215707 at world.std.com> bzs at world.std.com (Barry Shein) writes:
>Trying to close a closed file descriptor will cause -1 to be returned
>and errno set to EBADF. Close can also be interrupted (EINTR), I would

You get EBADF if you pass it something that isn't an open file descriptor,
whether it used to be one or not.

If you have a 4.2 BSD or earlier "more" (maybe still, I dunno) ask it
for help N times, where N is approximately equal to the maximum number
of file descriptors your kernel allows.  This demonstration "worked"
(ie, broke) last time I tried it on a Sun.

I'm told that the code is passing a FILE * to close(2), and not
checking the return value.  Naughty Naughty.

On the other hand, you should never check for an error that you
don't know what to do about.  :-)
-- 
Steve Nuchia	      South Coast Computing Services      (713) 964-2462
	"Could we find tools that would teach their own use,
	 we should have discovered something truly beyond price."
		Socrates, in Plato's Republic



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