Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!cs.utexas.edu!usc!apple!veritas!tron
From: tron@veritas.uucp (Ronald S. Karr)
Newsgroups: comp.unix.wizards
Subject: Smail3, SunOS and shared libraries
Keywords: smail3 sunos shared-libraries
Message-ID: <1990Aug27.115140.27772@veritas.uucp>
Date: 27 Aug 90 11:51:40 GMT
Reply-To: tron@veritas.com (Ronald S. Karr)
Organization: VERITAS Software
Lines: 36

The Smail3 program does not run well on several recent releases of
SunOS, and I don't understand why.  I do not actually have a Sun
myself, so I can't look into the problem directly, though some of the
sites that have Smail3 sources and Sun machines have tried to find
the problem, and so far nobody has reported a solution.

The problem is this:  Smail3 cannot exec programs that require
shared libraries, if the smail binary is setuid to root, or is run
by root.  One time, over the phone, I talked someone through the
process of getting smail to exec an interactive shell by mailing
a message through smail.  This worked, but only commands without
shared libraries could be executed.

I can only think of a few things in the smail sources that might
cause these problems, and so everyone that I have talked to about
this believes that these should cause a problem.  These are the
things that may (even remotely conceivably) be related:

	1.  the environment is completely reinitialized.

	2.  all file descriptors greater than 2 are closed, both
	    at startup and before execing something in a forked
	    process.

	3.  setgid() and setuid() are used to set the effective
	    (and hopefully the real) user and group IDs before
	    execing another program.

I would very much appreciate a response from anyone who has an idea
on what the problem is and how it can be fixed.

One last note:  Smail3 runs just fine under SVR4.0, which has a very
similar (though not identical) shared library structure.
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