[mirror_ubuntu-bionic-kernel.git] / kernel / itimer.c

/*
 * linux/kernel/itimer.c
 *
 * Copyright (C) 1992 Darren Senn
 */

/* These are all the functions necessary to implement itimers */

#include <linux/mm.h>
#include <linux/smp_lock.h>
#include <linux/interrupt.h>
#include <linux/syscalls.h>
#include <linux/time.h>
#include <linux/posix-timers.h>
#include <linux/hrtimer.h>

#include <asm/uaccess.h>

/**
 * itimer_get_remtime - get remaining time for the timer
 *
 * @timer: the timer to read
 *
 * Returns the delta between the expiry time and now, which can be
 * less than zero or 1usec for an pending expired timer
 */
static struct timeval itimer_get_remtime(struct hrtimer *timer)
{
	ktime_t rem = hrtimer_get_remaining(timer);

	/*
	 * Racy but safe: if the itimer expires after the above
	 * hrtimer_get_remtime() call but before this condition
	 * then we return 0 - which is correct.
	 */
	if (hrtimer_active(timer)) {
		if (rem.tv64 <= 0)
			rem.tv64 = NSEC_PER_USEC;
	} else
		rem.tv64 = 0;

	return ktime_to_timeval(rem);
}

int do_getitimer(int which, struct itimerval *value)
{
	struct task_struct *tsk = current;
	cputime_t cinterval, cval;

	switch (which) {
	case ITIMER_REAL:
		spin_lock_irq(&tsk->sighand->siglock);
		value->it_value = itimer_get_remtime(&tsk->signal->real_timer);
		value->it_interval =
			ktime_to_timeval(tsk->signal->it_real_incr);
		spin_unlock_irq(&tsk->sighand->siglock);
		break;
	case ITIMER_VIRTUAL:
		read_lock(&tasklist_lock);
		spin_lock_irq(&tsk->sighand->siglock);
		cval = tsk->signal->it_virt_expires;
		cinterval = tsk->signal->it_virt_incr;
		if (!cputime_eq(cval, cputime_zero)) {
			struct task_struct *t = tsk;
			cputime_t utime = tsk->signal->utime;
			do {
				utime = cputime_add(utime, t->utime);
				t = next_thread(t);
			} while (t != tsk);
			if (cputime_le(cval, utime)) { /* about to fire */
				cval = jiffies_to_cputime(1);
			} else {
				cval = cputime_sub(cval, utime);
			}
		}
		spin_unlock_irq(&tsk->sighand->siglock);
		read_unlock(&tasklist_lock);
		cputime_to_timeval(cval, &value->it_value);
		cputime_to_timeval(cinterval, &value->it_interval);
		break;
	case ITIMER_PROF:
		read_lock(&tasklist_lock);
		spin_lock_irq(&tsk->sighand->siglock);
		cval = tsk->signal->it_prof_expires;
		cinterval = tsk->signal->it_prof_incr;
		if (!cputime_eq(cval, cputime_zero)) {
			struct task_struct *t = tsk;
			cputime_t ptime = cputime_add(tsk->signal->utime,
						      tsk->signal->stime);
			do {
				ptime = cputime_add(ptime,
						    cputime_add(t->utime,
								t->stime));
				t = next_thread(t);
			} while (t != tsk);
			if (cputime_le(cval, ptime)) { /* about to fire */
				cval = jiffies_to_cputime(1);
			} else {
				cval = cputime_sub(cval, ptime);
			}
		}
		spin_unlock_irq(&tsk->sighand->siglock);
		read_unlock(&tasklist_lock);
		cputime_to_timeval(cval, &value->it_value);
		cputime_to_timeval(cinterval, &value->it_interval);
		break;
	default:
		return(-EINVAL);
	}
	return 0;
}

asmlinkage long sys_getitimer(int which, struct itimerval __user *value)
{
	int error = -EFAULT;
	struct itimerval get_buffer;

	if (value) {
		error = do_getitimer(which, &get_buffer);
		if (!error &&
		    copy_to_user(value, &get_buffer, sizeof(get_buffer)))
			error = -EFAULT;
	}
	return error;
}


/*
 * The timer is automagically restarted, when interval != 0
 */
int it_real_fn(struct hrtimer *timer)
{
	struct signal_struct *sig =
	    container_of(timer, struct signal_struct, real_timer);

	send_group_sig_info(SIGALRM, SEND_SIG_PRIV, sig->tsk);

	if (sig->it_real_incr.tv64 != 0) {
		hrtimer_forward(timer, timer->base->softirq_time,
				sig->it_real_incr);
		return HRTIMER_RESTART;
	}
	return HRTIMER_NORESTART;
}

/*
 * We do not care about correctness. We just sanitize the values so
 * the ktime_t operations which expect normalized values do not
 * break. This converts negative values to long timeouts similar to
 * the code in kernel versions < 2.6.16
 *
 * Print a limited number of warning messages when an invalid timeval
 * is detected.
 */
static void fixup_timeval(struct timeval *tv, int interval)
{
	static int warnlimit = 10;
	unsigned long tmp;

	if (warnlimit > 0) {
		warnlimit--;
		printk(KERN_WARNING
		       "setitimer: %s (pid = %d) provided "
		       "invalid timeval %s: tv_sec = %ld tv_usec = %ld\n",
		       current->comm, current->pid,
		       interval ? "it_interval" : "it_value",
		       tv->tv_sec, (long) tv->tv_usec);
	}

	tmp = tv->tv_usec;
	if (tmp >= USEC_PER_SEC) {
		tv->tv_usec = tmp % USEC_PER_SEC;
		tv->tv_sec += tmp / USEC_PER_SEC;
	}

	tmp = tv->tv_sec;
	if (tmp > LONG_MAX)
		tv->tv_sec = LONG_MAX;
}

/*
 * Returns true if the timeval is in canonical form
 */
#define timeval_valid(t) \
	(((t)->tv_sec >= 0) && (((unsigned long) (t)->tv_usec) < USEC_PER_SEC))

/*
 * Check for invalid timevals, sanitize them and print a limited
 * number of warnings.
 */
static void check_itimerval(struct itimerval *value) {

	if (unlikely(!timeval_valid(&value->it_value)))
		fixup_timeval(&value->it_value, 0);

	if (unlikely(!timeval_valid(&value->it_interval)))
		fixup_timeval(&value->it_interval, 1);
}

int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue)
{
	struct task_struct *tsk = current;
	struct hrtimer *timer;
	ktime_t expires;
	cputime_t cval, cinterval, nval, ninterval;

	/*
	 * Validate the timevals in value.
	 *
	 * Note: Although the spec requires that invalid values shall
	 * return -EINVAL, we just fixup the value and print a limited
	 * number of warnings in order not to break users of this
	 * historical misfeature.
	 *
	 * Scheduled for replacement in March 2007
	 */
	check_itimerval(value);

	switch (which) {
	case ITIMER_REAL:
again:
		spin_lock_irq(&tsk->sighand->siglock);
		timer = &tsk->signal->real_timer;
		if (ovalue) {
			ovalue->it_value = itimer_get_remtime(timer);
			ovalue->it_interval
				= ktime_to_timeval(tsk->signal->it_real_incr);
		}
		/* We are sharing ->siglock with it_real_fn() */
		if (hrtimer_try_to_cancel(timer) < 0) {
			spin_unlock_irq(&tsk->sighand->siglock);
			goto again;
		}
		tsk->signal->it_real_incr =
			timeval_to_ktime(value->it_interval);
		expires = timeval_to_ktime(value->it_value);
		if (expires.tv64 != 0)
			hrtimer_start(timer, expires, HRTIMER_REL);
		spin_unlock_irq(&tsk->sighand->siglock);
		break;
	case ITIMER_VIRTUAL:
		nval = timeval_to_cputime(&value->it_value);
		ninterval = timeval_to_cputime(&value->it_interval);
		read_lock(&tasklist_lock);
		spin_lock_irq(&tsk->sighand->siglock);
		cval = tsk->signal->it_virt_expires;
		cinterval = tsk->signal->it_virt_incr;
		if (!cputime_eq(cval, cputime_zero) ||
		    !cputime_eq(nval, cputime_zero)) {
			if (cputime_gt(nval, cputime_zero))
				nval = cputime_add(nval,
						   jiffies_to_cputime(1));
			set_process_cpu_timer(tsk, CPUCLOCK_VIRT,
					      &nval, &cval);
		}
		tsk->signal->it_virt_expires = nval;
		tsk->signal->it_virt_incr = ninterval;
		spin_unlock_irq(&tsk->sighand->siglock);
		read_unlock(&tasklist_lock);
		if (ovalue) {
			cputime_to_timeval(cval, &ovalue->it_value);
			cputime_to_timeval(cinterval, &ovalue->it_interval);
		}
		break;
	case ITIMER_PROF:
		nval = timeval_to_cputime(&value->it_value);
		ninterval = timeval_to_cputime(&value->it_interval);
		read_lock(&tasklist_lock);
		spin_lock_irq(&tsk->sighand->siglock);
		cval = tsk->signal->it_prof_expires;
		cinterval = tsk->signal->it_prof_incr;
		if (!cputime_eq(cval, cputime_zero) ||
		    !cputime_eq(nval, cputime_zero)) {
			if (cputime_gt(nval, cputime_zero))
				nval = cputime_add(nval,
						   jiffies_to_cputime(1));
			set_process_cpu_timer(tsk, CPUCLOCK_PROF,
					      &nval, &cval);
		}
		tsk->signal->it_prof_expires = nval;
		tsk->signal->it_prof_incr = ninterval;
		spin_unlock_irq(&tsk->sighand->siglock);
		read_unlock(&tasklist_lock);
		if (ovalue) {
			cputime_to_timeval(cval, &ovalue->it_value);
			cputime_to_timeval(cinterval, &ovalue->it_interval);
		}
		break;
	default:
		return -EINVAL;
	}
	return 0;
}

/**
 * alarm_setitimer - set alarm in seconds
 *
 * @seconds:	number of seconds until alarm
 *		0 disables the alarm
 *
 * Returns the remaining time in seconds of a pending timer or 0 when
 * the timer is not active.
 *
 * On 32 bit machines the seconds value is limited to (INT_MAX/2) to avoid
 * negative timeval settings which would cause immediate expiry.
 */
unsigned int alarm_setitimer(unsigned int seconds)
{
	struct itimerval it_new, it_old;

#if BITS_PER_LONG < 64
	if (seconds > INT_MAX)
		seconds = INT_MAX;
#endif
	it_new.it_value.tv_sec = seconds;
	it_new.it_value.tv_usec = 0;
	it_new.it_interval.tv_sec = it_new.it_interval.tv_usec = 0;

	do_setitimer(ITIMER_REAL, &it_new, &it_old);

	/*
	 * We can't return 0 if we have an alarm pending ...  And we'd
	 * better return too much than too little anyway
	 */
	if ((!it_old.it_value.tv_sec && it_old.it_value.tv_usec) ||
	      it_old.it_value.tv_usec >= 500000)
		it_old.it_value.tv_sec++;

	return it_old.it_value.tv_sec;
}

asmlinkage long sys_setitimer(int which,
			      struct itimerval __user *value,
			      struct itimerval __user *ovalue)
{
	struct itimerval set_buffer, get_buffer;
	int error;

	if (value) {
		if(copy_from_user(&set_buffer, value, sizeof(set_buffer)))
			return -EFAULT;
	} else
		memset((char *) &set_buffer, 0, sizeof(set_buffer));

	error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL);
	if (error || !ovalue)
		return error;

	if (copy_to_user(ovalue, &get_buffer, sizeof(get_buffer)))
		return -EFAULT; 
	return 0;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/kernel/itimer.c
	3	*
	4	* Copyright (C) 1992 Darren Senn
	5	*/
	6
	7	/* These are all the functions necessary to implement itimers */
	8
	9	#include <linux/mm.h>
	10	#include <linux/smp_lock.h>
	11	#include <linux/interrupt.h>
	12	#include <linux/syscalls.h>
	13	#include <linux/time.h>
	14	#include <linux/posix-timers.h>
2ff678b8	15	#include <linux/hrtimer.h>
1da177e4 LT	16
	17	#include <asm/uaccess.h>
	18
2ff678b8 TG	19	/**
	20	* itimer_get_remtime - get remaining time for the timer
	21	*
	22	* @timer: the timer to read
	23	*
	24	* Returns the delta between the expiry time and now, which can be
	25	* less than zero or 1usec for an pending expired timer
	26	*/
	27	static struct timeval itimer_get_remtime(struct hrtimer *timer)
1da177e4	28	{
2ff678b8	29	ktime_t rem = hrtimer_get_remaining(timer);
1da177e4	30
2ff678b8 TG	31	/*
	32	* Racy but safe: if the itimer expires after the above
	33	* hrtimer_get_remtime() call but before this condition
	34	* then we return 0 - which is correct.
	35	*/
	36	if (hrtimer_active(timer)) {
	37	if (rem.tv64 <= 0)
	38	rem.tv64 = NSEC_PER_USEC;
	39	} else
	40	rem.tv64 = 0;
	41
	42	return ktime_to_timeval(rem);
1da177e4 LT	43	}
	44
	45	int do_getitimer(int which, struct itimerval *value)
	46	{
	47	struct task_struct *tsk = current;
1da177e4 LT	48	cputime_t cinterval, cval;
	49
	50	switch (which) {
	51	case ITIMER_REAL:
bc1978d4	52	spin_lock_irq(&tsk->sighand->siglock);
2ff678b8 TG	53	value->it_value = itimer_get_remtime(&tsk->signal->real_timer);
	54	value->it_interval =
	55	ktime_to_timeval(tsk->signal->it_real_incr);
bc1978d4	56	spin_unlock_irq(&tsk->sighand->siglock);
1da177e4 LT	57	break;
	58	case ITIMER_VIRTUAL:
	59	read_lock(&tasklist_lock);
	60	spin_lock_irq(&tsk->sighand->siglock);
	61	cval = tsk->signal->it_virt_expires;
	62	cinterval = tsk->signal->it_virt_incr;
	63	if (!cputime_eq(cval, cputime_zero)) {
	64	struct task_struct *t = tsk;
	65	cputime_t utime = tsk->signal->utime;
	66	do {
	67	utime = cputime_add(utime, t->utime);
	68	t = next_thread(t);
	69	} while (t != tsk);
	70	if (cputime_le(cval, utime)) { /* about to fire */
	71	cval = jiffies_to_cputime(1);
	72	} else {
	73	cval = cputime_sub(cval, utime);
	74	}
	75	}
	76	spin_unlock_irq(&tsk->sighand->siglock);
	77	read_unlock(&tasklist_lock);
	78	cputime_to_timeval(cval, &value->it_value);
	79	cputime_to_timeval(cinterval, &value->it_interval);
	80	break;
	81	case ITIMER_PROF:
	82	read_lock(&tasklist_lock);
	83	spin_lock_irq(&tsk->sighand->siglock);
	84	cval = tsk->signal->it_prof_expires;
	85	cinterval = tsk->signal->it_prof_incr;
	86	if (!cputime_eq(cval, cputime_zero)) {
	87	struct task_struct *t = tsk;
	88	cputime_t ptime = cputime_add(tsk->signal->utime,
	89	tsk->signal->stime);
	90	do {
	91	ptime = cputime_add(ptime,
	92	cputime_add(t->utime,
	93	t->stime));
	94	t = next_thread(t);
	95	} while (t != tsk);
	96	if (cputime_le(cval, ptime)) { /* about to fire */
	97	cval = jiffies_to_cputime(1);
	98	} else {
	99	cval = cputime_sub(cval, ptime);
	100	}
	101	}
	102	spin_unlock_irq(&tsk->sighand->siglock);
	103	read_unlock(&tasklist_lock);
	104	cputime_to_timeval(cval, &value->it_value);
	105	cputime_to_timeval(cinterval, &value->it_interval);
	106	break;
	107	default:
	108	return(-EINVAL);
	109	}
	110	return 0;
	111	}
	112
	113	asmlinkage long sys_getitimer(int which, struct itimerval __user *value)
	114	{
	115	int error = -EFAULT;
	116	struct itimerval get_buffer;
	117
	118	if (value) {
	119	error = do_getitimer(which, &get_buffer);
	120	if (!error &&
121	copy_to_user(value, &get_buffer, sizeof(get_buffer)))
122	error = -EFAULT;
123	}
124	return error;
125	}
126
1da177e4	127
2ff678b8 TG	128	/*
	129	* The timer is automagically restarted, when interval != 0
	130	*/
05cfb614	131	int it_real_fn(struct hrtimer *timer)
1da177e4	132	{
05cfb614 RZ	133	struct signal_struct *sig =
05cfb614 RZ	134	container_of(timer, struct signal_struct, real_timer);
1da177e4	135
05cfb614	136	send_group_sig_info(SIGALRM, SEND_SIG_PRIV, sig->tsk);
2ff678b8	137
05cfb614 RZ	138	if (sig->it_real_incr.tv64 != 0) {
	139	hrtimer_forward(timer, timer->base->softirq_time,
	140	sig->it_real_incr);
2ff678b8 TG	141	return HRTIMER_RESTART;
	142	}
	143	return HRTIMER_NORESTART;
1da177e4 LT	144	}
1da177e4 LT	145
7d99b7d6 TG	146	/*
	147	* We do not care about correctness. We just sanitize the values so
	148	* the ktime_t operations which expect normalized values do not
	149	* break. This converts negative values to long timeouts similar to
	150	* the code in kernel versions < 2.6.16
	151	*
	152	* Print a limited number of warning messages when an invalid timeval
	153	* is detected.
	154	*/
	155	static void fixup_timeval(struct timeval *tv, int interval)
	156	{
	157	static int warnlimit = 10;
	158	unsigned long tmp;
	159
	160	if (warnlimit > 0) {
	161	warnlimit--;
	162	printk(KERN_WARNING
	163	"setitimer: %s (pid = %d) provided "
	164	"invalid timeval %s: tv_sec = %ld tv_usec = %ld\n",
	165	current->comm, current->pid,
	166	interval ? "it_interval" : "it_value",
	167	tv->tv_sec, (long) tv->tv_usec);
	168	}
	169
	170	tmp = tv->tv_usec;
	171	if (tmp >= USEC_PER_SEC) {
	172	tv->tv_usec = tmp % USEC_PER_SEC;
	173	tv->tv_sec += tmp / USEC_PER_SEC;
	174	}
	175
	176	tmp = tv->tv_sec;
	177	if (tmp > LONG_MAX)
	178	tv->tv_sec = LONG_MAX;
	179	}
	180
	181	/*
	182	* Returns true if the timeval is in canonical form
	183	*/
	184	#define timeval_valid(t) \
	185	(((t)->tv_sec >= 0) && (((unsigned long) (t)->tv_usec) < USEC_PER_SEC))
	186
	187	/*
	188	* Check for invalid timevals, sanitize them and print a limited
	189	* number of warnings.
	190	*/
	191	static void check_itimerval(struct itimerval *value) {
	192
	193	if (unlikely(!timeval_valid(&value->it_value)))
	194	fixup_timeval(&value->it_value, 0);
	195
	196	if (unlikely(!timeval_valid(&value->it_interval)))
	197	fixup_timeval(&value->it_interval, 1);
	198	}
	199
1da177e4 LT	200	int do_setitimer(int which, struct itimerval value, struct itimerval ovalue)
	201	{
	202	struct task_struct *tsk = current;
2ff678b8 TG	203	struct hrtimer *timer;
2ff678b8 TG	204	ktime_t expires;
1da177e4 LT	205	cputime_t cval, cinterval, nval, ninterval;
1da177e4 LT	206
7d99b7d6 TG	207	/*
	208	* Validate the timevals in value.
	209	*
	210	* Note: Although the spec requires that invalid values shall
	211	* return -EINVAL, we just fixup the value and print a limited
	212	* number of warnings in order not to break users of this
	213	* historical misfeature.
	214	*
	215	* Scheduled for replacement in March 2007
	216	*/
	217	check_itimerval(value);
	218
1da177e4 LT	219	switch (which) {
1da177e4 LT	220	case ITIMER_REAL:
bc1978d4 TG	221	again:
bc1978d4 TG	222	spin_lock_irq(&tsk->sighand->siglock);
2ff678b8	223	timer = &tsk->signal->real_timer;
1da177e4	224	if (ovalue) {
2ff678b8 TG	225	ovalue->it_value = itimer_get_remtime(timer);
	226	ovalue->it_interval
	227	= ktime_to_timeval(tsk->signal->it_real_incr);
1da177e4	228	}
a16a1c09 TG	229	/* We are sharing ->siglock with it_real_fn() */
	230	if (hrtimer_try_to_cancel(timer) < 0) {
	231	spin_unlock_irq(&tsk->sighand->siglock);
	232	goto again;
	233	}
2ff678b8 TG	234	tsk->signal->it_real_incr =
	235	timeval_to_ktime(value->it_interval);
	236	expires = timeval_to_ktime(value->it_value);
	237	if (expires.tv64 != 0)
	238	hrtimer_start(timer, expires, HRTIMER_REL);
bc1978d4	239	spin_unlock_irq(&tsk->sighand->siglock);
1da177e4 LT	240	break;
	241	case ITIMER_VIRTUAL:
	242	nval = timeval_to_cputime(&value->it_value);
	243	ninterval = timeval_to_cputime(&value->it_interval);
	244	read_lock(&tasklist_lock);
	245	spin_lock_irq(&tsk->sighand->siglock);
	246	cval = tsk->signal->it_virt_expires;
	247	cinterval = tsk->signal->it_virt_incr;
	248	if (!cputime_eq(cval, cputime_zero) \|\|
	249	!cputime_eq(nval, cputime_zero)) {
	250	if (cputime_gt(nval, cputime_zero))
	251	nval = cputime_add(nval,
	252	jiffies_to_cputime(1));
	253	set_process_cpu_timer(tsk, CPUCLOCK_VIRT,
	254	&nval, &cval);
	255	}
	256	tsk->signal->it_virt_expires = nval;
	257	tsk->signal->it_virt_incr = ninterval;
	258	spin_unlock_irq(&tsk->sighand->siglock);
	259	read_unlock(&tasklist_lock);
	260	if (ovalue) {
	261	cputime_to_timeval(cval, &ovalue->it_value);
	262	cputime_to_timeval(cinterval, &ovalue->it_interval);
	263	}
	264	break;
	265	case ITIMER_PROF:
	266	nval = timeval_to_cputime(&value->it_value);
	267	ninterval = timeval_to_cputime(&value->it_interval);
	268	read_lock(&tasklist_lock);
	269	spin_lock_irq(&tsk->sighand->siglock);
	270	cval = tsk->signal->it_prof_expires;
	271	cinterval = tsk->signal->it_prof_incr;
	272	if (!cputime_eq(cval, cputime_zero) \|\|
	273	!cputime_eq(nval, cputime_zero)) {
	274	if (cputime_gt(nval, cputime_zero))
	275	nval = cputime_add(nval,
	276	jiffies_to_cputime(1));
	277	set_process_cpu_timer(tsk, CPUCLOCK_PROF,
	278	&nval, &cval);
	279	}
	280	tsk->signal->it_prof_expires = nval;
	281	tsk->signal->it_prof_incr = ninterval;
	282	spin_unlock_irq(&tsk->sighand->siglock);
	283	read_unlock(&tasklist_lock);
	284	if (ovalue) {
	285	cputime_to_timeval(cval, &ovalue->it_value);
	286	cputime_to_timeval(cinterval, &ovalue->it_interval);
	287	}
	288	break;
	289	default:
	290	return -EINVAL;
	291	}
	292	return 0;
	293	}
	294
c08b8a49 TG	295	/**
	296	* alarm_setitimer - set alarm in seconds
	297	*
	298	* @seconds: number of seconds until alarm
	299	* 0 disables the alarm
	300	*
	301	* Returns the remaining time in seconds of a pending timer or 0 when
	302	* the timer is not active.
	303	*
	304	* On 32 bit machines the seconds value is limited to (INT_MAX/2) to avoid
	305	* negative timeval settings which would cause immediate expiry.
	306	*/
	307	unsigned int alarm_setitimer(unsigned int seconds)
	308	{
	309	struct itimerval it_new, it_old;
	310
	311	#if BITS_PER_LONG < 64
	312	if (seconds > INT_MAX)
	313	seconds = INT_MAX;
	314	#endif
	315	it_new.it_value.tv_sec = seconds;
	316	it_new.it_value.tv_usec = 0;
	317	it_new.it_interval.tv_sec = it_new.it_interval.tv_usec = 0;
	318
	319	do_setitimer(ITIMER_REAL, &it_new, &it_old);
	320
	321	/*
	322	* We can't return 0 if we have an alarm pending ... And we'd
	323	* better return too much than too little anyway
	324	*/
	325	if ((!it_old.it_value.tv_sec && it_old.it_value.tv_usec) \|\|
	326	it_old.it_value.tv_usec >= 500000)
	327	it_old.it_value.tv_sec++;
	328
	329	return it_old.it_value.tv_sec;
	330	}
	331
1da177e4 LT	332	asmlinkage long sys_setitimer(int which,
	333	struct itimerval __user *value,
	334	struct itimerval __user *ovalue)
	335	{
	336	struct itimerval set_buffer, get_buffer;
	337	int error;
	338
	339	if (value) {
	340	if(copy_from_user(&set_buffer, value, sizeof(set_buffer)))
	341	return -EFAULT;
	342	} else
	343	memset((char *) &set_buffer, 0, sizeof(set_buffer));
	344
	345	error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL);
	346	if (error \|\| !ovalue)
	347	return error;
	348
	349	if (copy_to_user(ovalue, &get_buffer, sizeof(get_buffer)))
	350	return -EFAULT;
	351	return 0;
	352	}