hello world kmod

hello_world.c

#include <sys/param.h>
#include <sys/module.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/conf.h>

static int event_handler(struct module *module, int event, void *arg) {
        int e = 0;
        switch(event) {
                case MOD_LOAD:
                        uprintf("Hello world\n");
                        break;
                case MOD_SHUTDOWN:
                case MOD_UNLOAD:
                        break;
                default:
                        e = EOPNOTSUPP;
                        break;
        }

        return e;
}


DEV_MODULE(hello_world, event_handler, NULL);

Makefile

KMOD = hello_world
SRCS = hello_world.c

.include <bsd.kmod.mk>