How can I automatically set the core dump size on a single user?

Question

I am running OpenSUSE. I usually open the console with an interactive non-login shell bash, and frequently use tcsh after logon. I am writing some C code, compiling with gcc, and I'd like to have the core dump files created whenever an executable fails.

I know I can select manually the core dump size to be unlimited, but I don't want to type

limits coredumpsize unlimited

in tcsh or

ulimit -c unlimited

in the default shell bash every time I log on as my user.

Is there a way to set the core dump size automatically whenever I logon as user in bash and/or tcsh?

Answer 1

After a bit of research I may have solved the problem. Once I login to the UNIX machine, it redirects me to the home directory, according to the shell chosen, from the available ones on the system from the file \etc\passwd as follows:

alandella:x:1000:100:alandella:/home/alandella:/bin/bash

This explains the non-login interactive bash shell (konsole). The shell, let it be bash or tcsh runs, and the following files are read at login/logout:

~/.login  -> Executes cmds at login
~/.tcshrc ->               same as ~./bashrc in bash and ~./cshrc in csh
~/.logout ->               at logout

So, by adding the following lines to the ~/.tcshrc and ~/.bashrc files:

~/.bashrc -> ulimit -Sc X
~/.tcshrc -> limit coredumpsize X

where X is a value (kB) or unlimited, and it should do the trick.

Sometimes, it is told to also edit the ~/.profile file. I did not edit it, even if MY bash shell sources it at login. Why does it not make a difference? Because I always use a non-login shell, as I double-click konsole to open the terminal. The ~/.profile file is sourced at startup only in a login shell (usually sh, which I do not use). I have bash that looks at the following files in sequence:

.bash_profile -> .bash_login -> .profile

in MY case, the first two files do not exist, so bash sources .profile if I use a login shell.

NOTE. This operation must be done as root, and in order to make this trick work, the following conditions must/should be met:

1. That the file /etc/security/limits.conf sets suitable hard/soft limits for the user and root. If a hard limit of the core dump size of 2000 kB is imposed, then when we modify ~/.bashrc with 3000 kB, the core dump size limit will continue to be 2000 kB. Lookup limits.conf.

2. That the files under /etc/pam.d contain the session required pam_limits.so line, in order to allow the /etc/security/limits.conf settings to take place.

3. That the file /etc/sysctl.conf contains kernel.core_pattern = core.%e.%p, this sets the format of the generated core files, where %e is the executable filename and %p is the pid.