Re: [PATCH] kernel 2.4.19 & 2.5.38 - coredump sysctl

From: Michael Sinz (
Date: Fri Sep 20 2002 - 16:29:46 EST

Andrew Morton wrote:
> Michael Sinz wrote:
>>coredump name format control via sysctl
>>Provides for a way to securely move where core files show up and to
>>set the name pattern for core files to include the UID, Program,
>>Hostname, and/or PID of the process that caused the core dump.
> That seems a reasonable thing to want to do.
>>The following format options are available in that string:
>> %P The Process ID (current->pid)
>> %U The UID of the process (current->uid)
>> %N The command name of the process (current->comm)
>> %H The nodename of the system (system_utsname.nodename)
>> %% A "%"
>>For example, in my clusters, I have an NFS R/W mount at /coredumps
>>that all nodes have access to. The format string I use is:
>> sysctl -w "kernel.core_name_format=/coredumps/%H-%N-%P.core"
> Does it need to be this fancy? Why not just have:
> if (core_name_format is unset)
> use "core"
> else
> use core_name_format/nodename-uid-pid-comm.core
> which saves all that string format processing, while giving
> people everything they could want?

Well, it depends on if you really need the complex form or not.

There are some people who use a format of:


which places the core file in the current directory but adds in the
name of the program. (Something that is very nice when you have
a lot of programs that may core "together" when something bad happens)

The string processing is not that much work anyway (very small)
and, given the fact that I am about to write to disk a core dump,
it can not be a critical path/fast path issue either :-)

What can be done at the default pattern level in later kernels
would be to make it a bit more than just "core" (such as maybe
the "%N.%P.core" or something like that) but that is not that

Also, FreeBSD (yes, I know, it is not Linux) has a very simular
feature that we used for the FreeBSD clusters we built.

Michael Sinz -- Director, Systems Engineering -- Worldgate Communications
A master's secrets are only as good as
	the master's ability to explain them to others.

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