#include <sys/types.h>
#include <sys/param.h>
#include <sys/proc.h>
#include <sys/module.h>
#include <sys/sysent.h>
#include <sys/kernel.h>
#include <sys/systm.h>

static int
hello
(struct proc *p, void *arg)
{
  unsigned char *message = * ((unsigned char **) arg);
  printf("message = %s\n", message);
  return 0;
}

static struct sysent hello_sysent =
  { 1, hello };

static int offset = NO_SYSCALL;

static int
load
(struct module *module, int cmd, void *arg)
{
  int error = 0;
  switch (cmd)
    {
    case MOD_LOAD:
      printf("syscall loaded at %d\n", offset);
      break;
    case MOD_UNLOAD:
      printf("syscall unloaded at %d\n", offset);
      break;
    default:
      error = EINVAL;
      break;
    }
  return error;
}

SYSCALL_MODULE(messagepost, &offset, &hello_sysent, load, NULL);