Re: terminal problems with emacs

[Matthew Swift <swift@bu.edu>]

Making popclient setuid root removed that error, thanks very much.  

There are potential problems bout making something setuid root,
however, and I wonder if it isn't a bug in popclient that it doesn't
internally obtain the right priveleges when setting the biffbit.
What do others think?

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FYI, "chmod u+s" makes an executable file "setuid", which means as you
say, that it runs with the priveleges of the file's owner.

There is an equivalent "g+s" which makes an executable run "setgid",
that is, with the priveleges of the file's group.

Making anything setuid root poses a security risk, since sometimes the
priveleges of these programs can be turned to destructive purposes
with sneaky tricks that as a matter of policy aren't publicized by the
gurus who know about them. 

In some ways, these facts pertaining to file permissions are very
basic Unix, but there are some subtleties.  I have used Unix for
almost 8 years without understanding why a shell script that is setuid
userX can't read or execute a file that only userX can read or
execute.  The expected thing happens, however, with setgid scripts.
There is in general a complication in that the system keeps track of
"effective" and "real" user ids, and you can't change your real user
id without a C program.

Thanks for your response.  If you have any questions about file
permissions, let's take them offline, I'd be happy to try to answer
them. 

Matt