> int main()
> {
>      sigset_t set;
>      int status;

>      if (getpid() != 1) return 1;

>      sigfillset(&set);
>      sigprocmask(SIG_BLOCK, &set, 0);

>      if (fork()) for (;;) wait(&status);

>      sigprocmask(SIG_UNBLOCK, &set, 0);

>      setsid();
>      setpgid(0, 0);
>      return execve("/etc/rc", (char *[]){ "rc", 0 }, (char *[]){ 0 });
> }

     Let me remind you that the way to create a process is fork(). 
execve() does not create a process; it replaces the current program by 
another, within the same process. If you want to "spawn" a process 
running rc, you must invoke both fork() and then execve().

     fork() creates two identical processes. It returns the pid of the 
child in the old process and 0 in the new.

     If fork() returns 0, you are the new process and you execute rc, 
after unblocking the signals etc. If you are still the parent, you just 
wait() for children indefinitely.

     Didier

     I find strange that the code doesn't include sys/types.h and 
sys/wait.h .

     Didier