Article View: comp.bugs.4bsd
Article #13Re: cpio - segmentation violation
From: Patrick Place
Date: Sun, 18 Jun 1989 22:02
Date: Sun, 18 Jun 1989 22:02
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1767 bytes
In article <10406@smoke.BRL.MIL>, gwyn@smoke.BRL.MIL (Doug Gwyn) writes:
> In article <1120@servax0.essex.ac.uk> peter@essex.ac.uk (Allott P) writes:
> >The problem is that some users have files on their areas with a uid of -2.
>
> That NFS-induced modification to the concept of UID has caused numerous
> problems. AT&T UIDs are unsigned (i.e. nonnegative) integers, and AT&T
> UNIX software relies on this. (So did some BSD software.) The whole
> issue of NFS ID mapping has been a real mess.
It is not so much a matter of having negative uids (which I admit is
unusual) as that on Suns for example,
printf("%.6ho", -2)
will print a 10 character wide representation of -2, rather than
the requested 6 character representation. I had exactly this problem
and fixed it by casting the offending value to a halfword, having
masked off all but the last 16 bits. It seemed to work and allowed
me once again to read (and write) cpio archives. I will grant that
the fix is not pretty, but I could not come up with any other way to
make printf print out a 6 character wide value. To be fair, if I
recall my reading of the Sun manual page for printf, it doesn't
guarantee that it will limit the output to 6 characters, merely that
it will use 6 characters (ie pad if necessary).
Pat Place
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!rochester!pt.cs.cmu.edu!sei!prp From: prp@sei.cmu.edu (Patrick Place) Newsgroups: comp.bugs.4bsd Subject: Re: cpio - segmentation violation Keywords: cpio, negative UID Message-ID: <3517@fy.sei.cmu.edu> Date: 18 Jun 89 22:02:29 GMT References: <1120@servax0.essex.ac.uk> <10406@smoke.BRL.MIL> Organization: Carnegie-Mellon University (Software Engineering Institute), Pgh, PA Lines: 25