How to change core pattern only for a particular application?

Question

My application requires the core file to be generated in a specific pattern.

How do I do this without affecting other processes?

And how do I do this when /proc is read-only?

Answer 1

man core tells us:

Piping core dumps to a program

Since kernel 2.6.19, Linux supports an alternate syntax for the /proc/sys/kernel/core_pattern file. If the first character of this file is a pipe symbol (|), then the remainder of the line is interpreted as a program to be executed. Instead of being written to a disk file, the core dump is given as standard input to the program.

Note the following points:

• The program must be specified using an absolute pathname (or a pathname relative to the root directory, /), and must immediately follow the '|' character.

• The process created to run the program runs as user and group root.

• Command-line arguments can be supplied to the program (since Linux 2.6.24), delimited by white space (up to a total line length of 128 bytes).

• The command-line arguments can include any of the % specifiers listed above. For example, to pass the PID of the process that is being dumped, specify %p in an argument.

You can put a script there, like e.g.

| /path/to/myscript %p %s %c

You can detect which process is triggering the coredump: (man core):

       %%  a single % character
       %p  PID of dumped process
       %u  (numeric) real UID of dumped process
       %g  (numeric) real GID of dumped process
       %s  number of signal causing dump
       %t  time of dump, expressed as seconds since the Epoch,  1970-01-01
           00:00:00 +0000 (UTC)
       %h  hostname (same as nodename returned by uname(2))
       %e  executable filename (without path prefix)
       %E  pathname of executable, with slashes ('/') replaced by exclama‐
           tion marks ('!').
       %c  core file size soft resource limit of crashing  process  (since
           Linux 2.6.24)

Now all you have to do is "do the default thing" for other processes than your own