mkdir has stopped working - SCO Xenix

[Holger Veit]

In <15884 at smoke.brl.mil> gwyn at smoke.brl.mil (Doug Gwyn) writes:

>In article <1991Apr10.090338.4967 at nodecg.ncc.telecomwa.oz.au> baker at nodecg.ncc.telecomwa.oz.au (mark baker 4206813) writes:
>>One of my 386 machines running Xenix 2.3.2 has suddenly refused to let
>>any user, including root, from making a directory.

>On many UNIX implementations, presumably including yours,
>"mkdir" must be installed set-UID 0 in order to work.
>I would guess that somebody changed the owners of the system utilities,
>or their protection modes, or something like that.

I also first guessed that. Mkdir on Sys5 systems depends on the mknod(2) 
system call which is executable only by root. Mknod allocates a new Inode,
which is then linked into the tree, the directory file is then filled with the
'.' and '..' entries. Mknod requires root-only execution because you can easily
destroy file system consistency with wrong usage or faults. (the root always 
knows what s/he does :-)))))

But Mark Baker said above, that even root cannot make a directory. So, setuid 0
for mkdir is obviously not the problem. I think the effect can be simulated by
patching the /etc/passwd root entry to another UID than 0, which would be
a very ugly thing if it happened... :-)

Hope this helps.

Holger

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