Date: Wed, 30 Oct 1996 16:13:36 -0600 (CST) From: Joe Greco <jgreco@brasil.moneng.mei.com> To: MRC@CAC.Washington.EDU (Mark Crispin) Cc: jgreco@brasil.moneng.mei.com, terry@lambert.org, j@uriah.heep.sax.de, roberto@keltia.freenix.fr, current@FreeBSD.org, scrappy@ki.net Subject: Re: /var/mail (was: re: Help, permission problems...) Message-ID: <199610302213.QAA26662@brasil.moneng.mei.com> In-Reply-To: <MailManager.846701797.335.mrc@Ikkoku-Kan.Panda.COM> from "Mark Crispin" at Oct 30, 96 10:56:37 am
next in thread | previous in thread | raw e-mail | index | archive | help
> On Wed, 30 Oct 1996 08:51:27 -0600 (CST), Joe Greco wrote:
> > Has it ever dawned on you that if you were to make this sort of policy
> > decision bubble up to the surface via a Configure-like mechanism, in the
> > manner that Elm does, that this would completely solve your problem?
>
> No, this won't. Most people who have systems and install software do not know
> what an fcntl is. Most people who have systems and install software don't
> even build their own software.
Then, who does build their software?
Maybe you meant that somebody with a clue builds their software. But
then this would not be a problem.
Now, if you were really interested in a SOLUTION to this problem, rather
than just defending your position on the matter, you would consider a
Configure-style solution.
It should be trivial to figure out, even at run time. THINK about what I
am saying:
If a system has a mail spool that is mode 0755, you CAN NOT use .lock style
locking: it will not work. Not only IMAP but also Elm and other mail agents
WILL NOT be able to lock the mailboxes. IF this is the result of a local
configuration error, it is MUCH more serious than just your one agent.
HOWEVER, it is very likely that a system with mode 0755 was set up
specifically because the mail system was engineered to handle that.
If a system has a mode 0775 mail spool, AND the program has been started
setgid, then you may clearly use .lock style locking, and the system
appears to be suggesting this to you. There is no harm in doing so.
If a system has mode 0775 mail spool and the program has NOT been started
setgid, one could examine the setgid status of /bin/mail (/usr/bin/mail,
whatever the heck) to determine if your agent should be running setgid but
in fact is not. In that case, clearly a warning SHOULD be issued.
If a system has mode ?777 mail spool, you may clearly use .lock style
locking.
Using file locking in all cases is, apparently, at least not harmful,
and could probably be used consistently. I may be incorrect.
So, I remain confused: what is so freaking bad about working out a
Configure-style solution that:
1) Gets the mode on ${mailspooldir}
2) Gets the setgid status of ${systemdefaultmailprogram}
3) Compares them using the above matrix, and
4) Compiles your agent appropriately?
I would prefer that it actually ASK the user, after having set the
defaults appropriately, but I am not going to argue trivial details.
GEEEEEZ. It's not rocket science to do this stuff. I haven't been
naive enough to expect my code to compile identically on all boxes using
the same paradigms for the better part of a decade.
> If you are smart enough to know what the right answer is to "use fcntl or lock
> file", and understand all the implications of that decision when your system
> is in a heterogenuous NFS cluster, then you are smart enough to know how to
> look at the code and find the compile-time option to turn off a warning
> message.
Yes, I agree. So for the rest of the world, you want to print a confusing
and potentially worrisome message because their more sophisticated and
modern UNIX system does not conform to your idea of How The World Must
Work?
I'm lost as to why that must obviously be correct.
I've been building software under many UNIX variants for many years. All
the good packages attempt to make as many reasonable guesses as possible
about their environment. This generally allows an administrator to pull
the software out of the tarball, glance at README/INSTALL, maybe type
"sh Configure" or somesuch, and then type "make; make install".
Since this whole thread was started when Marc Fournier (who - as far as
I can tell - is a very competent systems administrator) ran into this
problem, it appears that your assertion that ""If you are smart enough to
know what the right answer[...], then you are smart enough to know how to
look at the code and find the compile-time option to turn off a warning""
is just not true.
> Do you even use the software in question? If not, then shut up and leave the
> discussion to those who have a stake in the question.
I've been dealing with mail systems, issues, and implementations for years.
I apologize if I didn't make that clear.
I've also been around long enough to recognize your name as someone who
is rather unlikely to be swayed by rational argument and modern
configuration practices. So please do not bother responding to this
message, since I know you think that I am wrong.
... Joe
-------------------------------------------------------------------------------
Joe Greco - Systems Administrator jgreco@ns.sol.net
Solaria Public Access UNIX - Milwaukee, WI 414/546-7968
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199610302213.QAA26662>