[zope2-tracker] [Bug 143623] Re: zope.conf: effective-user breaks clean segfault handling

[stephan_hofmockel]

I struggled also with (own) c-modules and 'effective-user', so I would like to share my experiences. 
First of all, I did my tests with  svn://svn.zope.org/repos/main/Zope/tags/2.12.3 Revision: 110486 python2.6 under Linux with Kernel Version 2.6.31

I created a little c-module to simplify work (see attachment). I hooked
this module into the Zope via a external method and checked first if
zdaemon restarts the server after executing the method.

>From my point of view this works fine. The server process is killed
completely and a new one is started by zdaemon.

Unfortunately no core-dump was written and I did these three points to
get it

 1) 'ulimit -c unlimited' If this value is smaller then the core-file to
be written, then no core-file is written.

 2) echo '/tmp/core' > /proc/sys/kernel/core_pattern In default mode the
core file is written to the current working directory. For a reason I
currently cannot explain, the default doesn't work and only after
setting it to a hardcoded path the file appears.

 3)  echo -n 2 > /proc/sys/fs/suid_dumpable According to
http://www.kernel.org/doc/man-pages/online/pages/man5/proc.5.html for
programs executing the seteuid call (which is done by 'dropPrivileges'
in Zope2/Startup/__init__.py)  no core-file is written by default.
Switching this value to 2 changes this behavior.

After applying all these 3 configurations a core-file was created.

** Attachment added: "segfault.c"
   http://launchpadlibrarian.net/43168314/segfault.c

-- 
zope.conf: effective-user breaks clean segfault handling
https://bugs.launchpad.net/bugs/143623
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