openssh interface

[Gorka Lendrino Vela]

Dear all,

This is my first post to this group so excuse me if this topic has been
solved previously.

If I want to shutdown a remote database, I could send a "systemctl stop
mariadb" command using ssh. But I wonder if it is possible to update the
openssh server to implement a specific handler/callback that catch this
message and then call a C/C++ code.

In short, is there any interface provided by the openssh server to add new
functionality or call a dynamic library that implements this functionality?

Thanks in advance,
Gorka