/*
 * pinexec.c -- pin self to a CPU (root) then exec.  Children inherit
 * the lwp cpu mask across fork/exec and credential changes, so this
 * launches both the root rig and (via su) the opuser weapon onto the
 * same CPU -- the DragonFly slab allocator is per-CPU, so shaping and
 * allocation must meet in the same per-CPU zone list.
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <sys/syscall.h>
#include <sys/usched.h>

int
main(int argc, char **argv)
{
	int cpu;

	if (argc < 3) {
		fprintf(stderr, "usage: pinexec <cpu> <cmd> [args...]\n");
		return (2);
	}
	cpu = atoi(argv[1]);
	if (syscall(SYS_usched_set, 0, USCHED_SET_CPU, &cpu,
	    sizeof(cpu)) != 0) {
		perror("usched_set");
		return (1);
	}
	execvp(argv[2], &argv[2]);
	perror("execvp");
	return (1);
}