On 1999/03/24, Mark Phillips wrote:
> > On 1999/03/23, Ruud de Rooij wrote:
> >
> > > Can you please try to reproduce it again, by running
> > >
> > > strace -o inc.trace inc -silent +tmp2
> >
> > which (obviously) won't work because inc is setgid.
>
> Please excuse my ignorance, but what is setgid and why does it mean
> strace wouldn't work?
setgid stands for set-group-id. It means that when you run inc, the system
will grant it additional privileges (the "mail" group) which are required
for creating lock files in the mail spool directory.
For security reasons, it is not allowed to trace privileged processes.
> > Can you still try to get a core file, and send that to me (gzipped)?
>
> I couldn't find a core file. Where should it end up --- in the
> directory that inc was run from? It's not there. (Nor could I find
> it anywhere else.)
>
> > If inc also segfaults if you run it with -file, you can try copying
> > /usr/bin/mh/inc to your own directory (so it'll lose its setgid bit) and
> > run it as
> >
> > strace -o inc.trace ./inc -silent -file mailbox +tmp2
>
> Okay, I've done this and included inc.trace, using X-uuencode. I'll also
> include the mail file again using X-uuencode, just in case last time something> was
>mucked up in the file transfer.
The trace file was useful, but not enough for me to determine where things
go wrong. In order to create a core dump file, you probably have to do
ulimit -c unlimited (if you're using the bash shell)
limit coredumpsize unlimited (if you're using the tcsh shell)
And then run inc again (strace is not needed). The file is named core, and
is placed in the directory you ran inc from. The same rule applies here for
privileged processes.
Thanks a lot for your cooperation in tracking down this bug!
Greetings,
Ruud de Rooij.
--
Ruud de Rooij
[EMAIL PROTECTED]
http://sepc.twi.tudelft.nl/~derooij/
