[9fans] what a mess the Unix world has become

[Aharon Robbins <arnold@skeeve.com>]

I forward this for the amusement of the list members.  My initial
reply to this question was that the "Unix guru gives up in disgust
and moves to Plan 9."  Would that I could.

Arnold

> Date: Sat, 8 Feb 2003 09:37:50 -0700 (MST)
> Subject: Readable files: a Unix philosophy question for gurus
>
> In "man test", we find this documentation:
>
>        -r FILE
>               FILE exists and is readable
>
> Similar wording appears in vendor man pages, although Compaq OSF/1
> is a bit more precise:
>
>        -r file
>            TRUE if file exists and has read permission.
>
> Consider a file with these permissions:
>
> 	% ls -l foo.xml
> 	-rwSr-Srwx    2 beebe    staff      174440 Feb  8 08:20 foo.xml
>
> created by
>
> 	chmod u+s,g+s,o+rwxt foo.xml
>
> Now look at this:
>
> (1) On the file server:
>
> 	/bin/test -r foo.xml && echo file is readable
> 	file is readable
>
> 	/usr/local/bin/test -r foo.xml && echo file is readable
> 	file is readable
>
> 	/usr/local/bin/test --version
> 	test (GNU coreutils) 4.5.6
> 	...
>
> 	/bin/cat foo.xml > /dev/null
>
> 	echo $?
> 	0
>
> (2) On a [Sun Solaris 2.8] client, where the filesystem is mounted via
>     NFS with the attributes remote/read/write/nosuid/grpid/intr/noquota:
>
> 	/bin/test -r foo.xml && echo file is readable
> 	[no output]
>
> 	/usr/local/bin/test -r foo.xml && echo file is readable
> 	file is readable
>
> 	/bin/cat foo.xml > /dev/null
> 	cat: cannot open foo.xml
>
> 	/usr/local/bin/cat foo.xml > /dev/null
> 	/usr/local/bin/cat: foo.xml: Permission denied
>
> 	echo $?
> 	1
>
> The $65,536 question is: what should test report?  In this case, the
> setuid bit combined with the mount options makes the file unreadable,
> and the Solaris test command reflects that, but the GNU coreutils
> one does not.
>
> Experiments with native test on other systems produced these results:
>
> 	SGI IRIX 6.5:		file is readable, cat fails
> 	Compaq OSF/1 4.0:	no output from test, cat fails
>
> On AIX, my home filesystem is not mounted with special attributes, so
> I could not make the same experiment.
>
> On FreeBSD, chmod would not do g+s or o+t for me, and the file
> remained readable for both test and cat.
>
> My feeling is that the GNU version of test (going back to at least
> sh-utils 2.0.11 on Red Hat 7.2, and likely much earlier), and the IRIX
> version too, are wrong.
>
> I think that one really should be able to do "test -r foo && cat foo"
> without cat failing because of permissions.
>
> Comments?