[linux-2.6-block.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(void *data)
{
	struct task_struct *tsk = (struct task_struct *) data;

	send_group_sig_info(SIGALRM, SEND_SIG_PRIV, tsk);

	if (tsk->signal->it_real_incr.tv64 != 0) {
		hrtimer_forward(&tsk->signal->real_timer,
				tsk->signal->real_timer.base->softirq_time,
				tsk->signal->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	*/
	131	int it_real_fn(void *data)
1da177e4	132	{
2ff678b8	133	struct task_struct tsk = (struct task_struct ) data;
1da177e4	134
2ff678b8	135	send_group_sig_info(SIGALRM, SEND_SIG_PRIV, tsk);
1da177e4	136
2ff678b8 TG	137	if (tsk->signal->it_real_incr.tv64 != 0) {
2ff678b8 TG	138	hrtimer_forward(&tsk->signal->real_timer,
44f21475 RZ	139	tsk->signal->real_timer.base->softirq_time,
44f21475 RZ	140	tsk->signal->it_real_incr);
2ff678b8 TG	141
	142	return HRTIMER_RESTART;
	143	}
	144	return HRTIMER_NORESTART;
1da177e4 LT	145	}
1da177e4 LT	146
7d99b7d6 TG	147	/*
	148	* We do not care about correctness. We just sanitize the values so
	149	* the ktime_t operations which expect normalized values do not
	150	* break. This converts negative values to long timeouts similar to
	151	* the code in kernel versions < 2.6.16
	152	*
	153	* Print a limited number of warning messages when an invalid timeval
	154	* is detected.
	155	*/
	156	static void fixup_timeval(struct timeval *tv, int interval)
	157	{
	158	static int warnlimit = 10;
	159	unsigned long tmp;
	160
	161	if (warnlimit > 0) {
	162	warnlimit--;
	163	printk(KERN_WARNING
	164	"setitimer: %s (pid = %d) provided "
	165	"invalid timeval %s: tv_sec = %ld tv_usec = %ld\n",
	166	current->comm, current->pid,
	167	interval ? "it_interval" : "it_value",
	168	tv->tv_sec, (long) tv->tv_usec);
	169	}
	170
	171	tmp = tv->tv_usec;
	172	if (tmp >= USEC_PER_SEC) {
	173	tv->tv_usec = tmp % USEC_PER_SEC;
	174	tv->tv_sec += tmp / USEC_PER_SEC;
	175	}
	176
	177	tmp = tv->tv_sec;
	178	if (tmp > LONG_MAX)
	179	tv->tv_sec = LONG_MAX;
	180	}
	181
	182	/*
	183	* Returns true if the timeval is in canonical form
	184	*/
	185	#define timeval_valid(t) \
	186	(((t)->tv_sec >= 0) && (((unsigned long) (t)->tv_usec) < USEC_PER_SEC))
	187
	188	/*
	189	* Check for invalid timevals, sanitize them and print a limited
	190	* number of warnings.
	191	*/
	192	static void check_itimerval(struct itimerval *value) {
	193
	194	if (unlikely(!timeval_valid(&value->it_value)))
	195	fixup_timeval(&value->it_value, 0);
	196
	197	if (unlikely(!timeval_valid(&value->it_interval)))
	198	fixup_timeval(&value->it_interval, 1);
	199	}
	200
1da177e4 LT	201	int do_setitimer(int which, struct itimerval value, struct itimerval ovalue)
	202	{
	203	struct task_struct *tsk = current;
2ff678b8 TG	204	struct hrtimer *timer;
2ff678b8 TG	205	ktime_t expires;
1da177e4 LT	206	cputime_t cval, cinterval, nval, ninterval;
1da177e4 LT	207
7d99b7d6 TG	208	/*
	209	* Validate the timevals in value.
	210	*
	211	* Note: Although the spec requires that invalid values shall
	212	* return -EINVAL, we just fixup the value and print a limited
	213	* number of warnings in order not to break users of this
	214	* historical misfeature.
	215	*
	216	* Scheduled for replacement in March 2007
	217	*/
	218	check_itimerval(value);
	219
1da177e4 LT	220	switch (which) {
1da177e4 LT	221	case ITIMER_REAL:
bc1978d4 TG	222	again:
bc1978d4 TG	223	spin_lock_irq(&tsk->sighand->siglock);
2ff678b8	224	timer = &tsk->signal->real_timer;
1da177e4	225	if (ovalue) {
2ff678b8 TG	226	ovalue->it_value = itimer_get_remtime(timer);
	227	ovalue->it_interval
	228	= ktime_to_timeval(tsk->signal->it_real_incr);
1da177e4	229	}
a16a1c09 TG	230	/* We are sharing ->siglock with it_real_fn() */
	231	if (hrtimer_try_to_cancel(timer) < 0) {
	232	spin_unlock_irq(&tsk->sighand->siglock);
	233	goto again;
	234	}
2ff678b8 TG	235	tsk->signal->it_real_incr =
	236	timeval_to_ktime(value->it_interval);
	237	expires = timeval_to_ktime(value->it_value);
	238	if (expires.tv64 != 0)
	239	hrtimer_start(timer, expires, HRTIMER_REL);
bc1978d4	240	spin_unlock_irq(&tsk->sighand->siglock);
1da177e4 LT	241	break;
	242	case ITIMER_VIRTUAL:
	243	nval = timeval_to_cputime(&value->it_value);
	244	ninterval = timeval_to_cputime(&value->it_interval);
	245	read_lock(&tasklist_lock);
	246	spin_lock_irq(&tsk->sighand->siglock);
	247	cval = tsk->signal->it_virt_expires;
	248	cinterval = tsk->signal->it_virt_incr;
	249	if (!cputime_eq(cval, cputime_zero) \|\|
	250	!cputime_eq(nval, cputime_zero)) {
	251	if (cputime_gt(nval, cputime_zero))
	252	nval = cputime_add(nval,
	253	jiffies_to_cputime(1));
	254	set_process_cpu_timer(tsk, CPUCLOCK_VIRT,
	255	&nval, &cval);
	256	}
	257	tsk->signal->it_virt_expires = nval;
	258	tsk->signal->it_virt_incr = ninterval;
	259	spin_unlock_irq(&tsk->sighand->siglock);
	260	read_unlock(&tasklist_lock);
	261	if (ovalue) {
	262	cputime_to_timeval(cval, &ovalue->it_value);
	263	cputime_to_timeval(cinterval, &ovalue->it_interval);
	264	}
	265	break;
	266	case ITIMER_PROF:
	267	nval = timeval_to_cputime(&value->it_value);
	268	ninterval = timeval_to_cputime(&value->it_interval);
	269	read_lock(&tasklist_lock);
	270	spin_lock_irq(&tsk->sighand->siglock);
	271	cval = tsk->signal->it_prof_expires;
	272	cinterval = tsk->signal->it_prof_incr;
	273	if (!cputime_eq(cval, cputime_zero) \|\|
	274	!cputime_eq(nval, cputime_zero)) {
	275	if (cputime_gt(nval, cputime_zero))
	276	nval = cputime_add(nval,
	277	jiffies_to_cputime(1));
	278	set_process_cpu_timer(tsk, CPUCLOCK_PROF,
	279	&nval, &cval);
	280	}
	281	tsk->signal->it_prof_expires = nval;
	282	tsk->signal->it_prof_incr = ninterval;
	283	spin_unlock_irq(&tsk->sighand->siglock);
	284	read_unlock(&tasklist_lock);
	285	if (ovalue) {
	286	cputime_to_timeval(cval, &ovalue->it_value);
	287	cputime_to_timeval(cinterval, &ovalue->it_interval);
	288	}
	289	break;
	290	default:
	291	return -EINVAL;
	292	}
	293	return 0;
	294	}
	295
c08b8a49 TG	296	/**
	297	* alarm_setitimer - set alarm in seconds
	298	*
	299	* @seconds: number of seconds until alarm
	300	* 0 disables the alarm
	301	*
	302	* Returns the remaining time in seconds of a pending timer or 0 when
	303	* the timer is not active.
	304	*
	305	* On 32 bit machines the seconds value is limited to (INT_MAX/2) to avoid
	306	* negative timeval settings which would cause immediate expiry.
	307	*/
	308	unsigned int alarm_setitimer(unsigned int seconds)
	309	{
	310	struct itimerval it_new, it_old;
	311
	312	#if BITS_PER_LONG < 64
	313	if (seconds > INT_MAX)
	314	seconds = INT_MAX;
	315	#endif
	316	it_new.it_value.tv_sec = seconds;
	317	it_new.it_value.tv_usec = 0;
	318	it_new.it_interval.tv_sec = it_new.it_interval.tv_usec = 0;
	319
	320	do_setitimer(ITIMER_REAL, &it_new, &it_old);
	321
	322	/*
	323	* We can't return 0 if we have an alarm pending ... And we'd
	324	* better return too much than too little anyway
	325	*/
	326	if ((!it_old.it_value.tv_sec && it_old.it_value.tv_usec) \|\|
	327	it_old.it_value.tv_usec >= 500000)
	328	it_old.it_value.tv_sec++;
	329
	330	return it_old.it_value.tv_sec;
	331	}
	332
1da177e4 LT	333	asmlinkage long sys_setitimer(int which,
	334	struct itimerval __user *value,
	335	struct itimerval __user *ovalue)
	336	{
	337	struct itimerval set_buffer, get_buffer;
	338	int error;
	339
	340	if (value) {
	341	if(copy_from_user(&set_buffer, value, sizeof(set_buffer)))
	342	return -EFAULT;
	343	} else
	344	memset((char *) &set_buffer, 0, sizeof(set_buffer));
	345
	346	error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL);
	347	if (error \|\| !ovalue)
	348	return error;
	349
	350	if (copy_to_user(ovalue, &get_buffer, sizeof(get_buffer)))
	351	return -EFAULT;
	352	return 0;
	353	}