How to make a function call before session initialization in Linux?

Question

linux

Good afternoon!
Is it possible to somehow execute a function before initializing a session in Linux via SSH?
Those. after someone logged in via SSH in the system, say by email, a notification about this came.
Is it possible to implement this in BASH, so that it would be possible to expand the script

Answer 1

linux.die.net/man/5/sshd_config

PermitUserRC
Specifies whether any ~/.ssh/rc file is executed. The default is "yes".
ForceCommand
Forces the execution of the command specified by ForceCommand, ignoring any command supplied by the client and ~/.ssh/rc if present. The command is invoked by using the user's login shell with the -c option. This
applies to shell, command, or subsystem execution. It is most useful inside a Match block. The command originally supplied by the client is available in the SSH_ORIGINAL_COMMAND environment variable. Specifying a
command of “internal-sftp” will force the use of an in-process sftp server that requires no support files when used with ChrootDirectory. The default is "none".