Debian: Add post install script

This DKMS script will be run when the package is installed.
It will run the standard DKMS build steps (compiling the module against
the current kernel version), and will additionally:

- Load the module immediately
- Configure the module to be loaded automatically at boot

This is not handled by default by DKMS, because usually, kernel modules
are associated with some hardware, and the hardware detection in the
kernel will be enough to load the module.

But, in the case of tty0tty, there is no associated hardware, and so,
the module must be explicitly loaded.

.gitignore

@@ -26,7 +26,8 @@ pts/tty0tty
 .pydevproject
 
 # debian packaging artifacts
-debian/*
+debian/.debhelper/
+debian/tty0tty-dkms/
 debhelper/*
 files
 *-dkms.debhelper.log

debian/postinst

@@ -0,0 +1,40 @@
+#!/bin/sh
+set -e
+# Automatically added by dh_dkms/3.0.10-8+deb12u1
+# The original file can be found in template-dkms-mkdeb/debian/postinst
+# in the DKMS tarball, check it for copyright notices.
+
+DKMS_NAME=tty0tty
+DKMS_PACKAGE_NAME=$DKMS_NAME-dkms
+DKMS_VERSION=1.2
+
+postinst_found=0
+
+case "$1" in
+	configure)
+		for DKMS_POSTINST in /usr/lib/dkms/common.postinst /usr/share/$DKMS_PACKAGE_NAME/postinst; do
+			if [ -f $DKMS_POSTINST ]; then
+				$DKMS_POSTINST $DKMS_NAME $DKMS_VERSION /usr/share/$DKMS_PACKAGE_NAME "" $2
+				postinst_found=1
+				break
+			fi
+		done
+		if [ "$postinst_found" -eq 0 ]; then
+			echo "ERROR: DKMS version is too old and $DKMS_PACKAGE_NAME was not"
+			echo "built with legacy DKMS support."
+			echo "You must either rebuild $DKMS_PACKAGE_NAME with legacy postinst"
+			echo "support or upgrade DKMS to a more current version."
+			exit 1
+		fi
+        # Load the tty0tty kernel module immediately
+        if ! lsmod | grep -q tty0tty; then
+            modprobe tty0tty
+        fi
+        # Ensure the module loads on boot
+        if ! grep -q "^tty0tty$" /etc/modules-load.d/tty0tty.conf; then
+            echo tty0tty >> /etc/modules-load.d/tty0tty.conf
+        fi
+	;;
+esac
+# End automatically added section
+exit 0