[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/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:
		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_cputime cputime;
			cputime_t utime;

			thread_group_cputimer(tsk, &cputime);
			utime = cputime.utime;
			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);
		cputime_to_timeval(cval, &value->it_value);
		cputime_to_timeval(cinterval, &value->it_interval);
		break;
	case ITIMER_PROF:
		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_cputime times;
			cputime_t ptime;

			thread_group_cputimer(tsk, &times);
			ptime = cputime_add(times.utime, times.stime);
			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);
		cputime_to_timeval(cval, &value->it_value);
		cputime_to_timeval(cinterval, &value->it_interval);
		break;
	default:
		return(-EINVAL);
	}
	return 0;
}

SYSCALL_DEFINE2(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
 */
enum hrtimer_restart it_real_fn(struct hrtimer *timer)
{
	struct signal_struct *sig =
		container_of(timer, struct signal_struct, real_timer);

	kill_pid_info(SIGALRM, SEND_SIG_PRIV, sig->leader_pid);

	return HRTIMER_NORESTART;
}

/*
 * 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))

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.
	 */
	if (!timeval_valid(&value->it_value) ||
	    !timeval_valid(&value->it_interval))
		return -EINVAL;

	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;
		}
		expires = timeval_to_ktime(value->it_value);
		if (expires.tv64 != 0) {
			tsk->signal->it_real_incr =
				timeval_to_ktime(value->it_interval);
			hrtimer_start(timer, expires, HRTIMER_MODE_REL);
		} else
			tsk->signal->it_real_incr.tv64 = 0;

		spin_unlock_irq(&tsk->sighand->siglock);
		break;
	case ITIMER_VIRTUAL:
		nval = timeval_to_cputime(&value->it_value);
		ninterval = timeval_to_cputime(&value->it_interval);
		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);
		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);
		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);
		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;
}

SYSCALL_DEFINE3(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>
1da177e4 LT	10	#include <linux/interrupt.h>
	11	#include <linux/syscalls.h>
	12	#include <linux/time.h>
	13	#include <linux/posix-timers.h>
2ff678b8	14	#include <linux/hrtimer.h>
1da177e4 LT	15
	16	#include <asm/uaccess.h>
	17
2ff678b8 TG	18	/**
	19	* itimer_get_remtime - get remaining time for the timer
	20	*
	21	* @timer: the timer to read
	22	*
	23	* Returns the delta between the expiry time and now, which can be
	24	* less than zero or 1usec for an pending expired timer
	25	*/
	26	static struct timeval itimer_get_remtime(struct hrtimer *timer)
1da177e4	27	{
2ff678b8	28	ktime_t rem = hrtimer_get_remaining(timer);
1da177e4	29
2ff678b8 TG	30	/*
	31	* Racy but safe: if the itimer expires after the above
	32	* hrtimer_get_remtime() call but before this condition
	33	* then we return 0 - which is correct.
	34	*/
	35	if (hrtimer_active(timer)) {
	36	if (rem.tv64 <= 0)
	37	rem.tv64 = NSEC_PER_USEC;
	38	} else
	39	rem.tv64 = 0;
	40
	41	return ktime_to_timeval(rem);
1da177e4 LT	42	}
	43
	44	int do_getitimer(int which, struct itimerval *value)
	45	{
	46	struct task_struct *tsk = current;
1da177e4 LT	47	cputime_t cinterval, cval;
	48
	49	switch (which) {
	50	case ITIMER_REAL:
bc1978d4	51	spin_lock_irq(&tsk->sighand->siglock);
2ff678b8 TG	52	value->it_value = itimer_get_remtime(&tsk->signal->real_timer);
	53	value->it_interval =
	54	ktime_to_timeval(tsk->signal->it_real_incr);
bc1978d4	55	spin_unlock_irq(&tsk->sighand->siglock);
1da177e4 LT	56	break;
1da177e4 LT	57	case ITIMER_VIRTUAL:
1da177e4 LT	58	spin_lock_irq(&tsk->sighand->siglock);
	59	cval = tsk->signal->it_virt_expires;
	60	cinterval = tsk->signal->it_virt_incr;
	61	if (!cputime_eq(cval, cputime_zero)) {
f06febc9 FM	62	struct task_cputime cputime;
	63	cputime_t utime;
	64
4cd4c1b4	65	thread_group_cputimer(tsk, &cputime);
f06febc9	66	utime = cputime.utime;
1da177e4 LT	67	if (cputime_le(cval, utime)) { /* about to fire */
	68	cval = jiffies_to_cputime(1);
	69	} else {
	70	cval = cputime_sub(cval, utime);
	71	}
	72	}
	73	spin_unlock_irq(&tsk->sighand->siglock);
1da177e4 LT	74	cputime_to_timeval(cval, &value->it_value);
	75	cputime_to_timeval(cinterval, &value->it_interval);
	76	break;
	77	case ITIMER_PROF:
1da177e4 LT	78	spin_lock_irq(&tsk->sighand->siglock);
	79	cval = tsk->signal->it_prof_expires;
	80	cinterval = tsk->signal->it_prof_incr;
	81	if (!cputime_eq(cval, cputime_zero)) {
f06febc9 FM	82	struct task_cputime times;
	83	cputime_t ptime;
	84
4cd4c1b4	85	thread_group_cputimer(tsk, &times);
f06febc9	86	ptime = cputime_add(times.utime, times.stime);
1da177e4 LT	87	if (cputime_le(cval, ptime)) { /* about to fire */
	88	cval = jiffies_to_cputime(1);
	89	} else {
	90	cval = cputime_sub(cval, ptime);
	91	}
	92	}
	93	spin_unlock_irq(&tsk->sighand->siglock);
1da177e4 LT	94	cputime_to_timeval(cval, &value->it_value);
	95	cputime_to_timeval(cinterval, &value->it_interval);
	96	break;
	97	default:
	98	return(-EINVAL);
	99	}
	100	return 0;
	101	}
	102
b290ebe2	103	SYSCALL_DEFINE2(getitimer, int, which, struct itimerval __user *, value)
1da177e4 LT	104	{
	105	int error = -EFAULT;
	106	struct itimerval get_buffer;
	107
	108	if (value) {
	109	error = do_getitimer(which, &get_buffer);
	110	if (!error &&
	111	copy_to_user(value, &get_buffer, sizeof(get_buffer)))
	112	error = -EFAULT;
	113	}
	114	return error;
	115	}
	116
1da177e4	117
2ff678b8 TG	118	/*
	119	* The timer is automagically restarted, when interval != 0
	120	*/
c9cb2e3d	121	enum hrtimer_restart it_real_fn(struct hrtimer *timer)
1da177e4	122	{
05cfb614	123	struct signal_struct *sig =
0719e370	124	container_of(timer, struct signal_struct, real_timer);
1da177e4	125
fea9d175	126	kill_pid_info(SIGALRM, SEND_SIG_PRIV, sig->leader_pid);
2ff678b8	127
2ff678b8	128	return HRTIMER_NORESTART;
1da177e4 LT	129	}
1da177e4 LT	130
7d99b7d6 TG	131	/*
	132	* Returns true if the timeval is in canonical form
	133	*/
	134	#define timeval_valid(t) \
	135	(((t)->tv_sec >= 0) && (((unsigned long) (t)->tv_usec) < USEC_PER_SEC))
	136
1da177e4 LT	137	int do_setitimer(int which, struct itimerval value, struct itimerval ovalue)
	138	{
	139	struct task_struct *tsk = current;
2ff678b8 TG	140	struct hrtimer *timer;
2ff678b8 TG	141	ktime_t expires;
1da177e4 LT	142	cputime_t cval, cinterval, nval, ninterval;
1da177e4 LT	143
7d99b7d6 TG	144	/*
7d99b7d6 TG	145	* Validate the timevals in value.
7d99b7d6	146	*/
35bab756 AB	147	if (!timeval_valid(&value->it_value) \|\|
	148	!timeval_valid(&value->it_interval))
	149	return -EINVAL;
7d99b7d6	150
1da177e4 LT	151	switch (which) {
1da177e4 LT	152	case ITIMER_REAL:
bc1978d4 TG	153	again:
bc1978d4 TG	154	spin_lock_irq(&tsk->sighand->siglock);
2ff678b8	155	timer = &tsk->signal->real_timer;
1da177e4	156	if (ovalue) {
2ff678b8 TG	157	ovalue->it_value = itimer_get_remtime(timer);
	158	ovalue->it_interval
	159	= ktime_to_timeval(tsk->signal->it_real_incr);
1da177e4	160	}
a16a1c09 TG	161	/* We are sharing ->siglock with it_real_fn() */
	162	if (hrtimer_try_to_cancel(timer) < 0) {
	163	spin_unlock_irq(&tsk->sighand->siglock);
	164	goto again;
	165	}
2ff678b8	166	expires = timeval_to_ktime(value->it_value);
8bfd9a7a TG	167	if (expires.tv64 != 0) {
	168	tsk->signal->it_real_incr =
	169	timeval_to_ktime(value->it_interval);
c9cb2e3d	170	hrtimer_start(timer, expires, HRTIMER_MODE_REL);
8bfd9a7a TG	171	} else
	172	tsk->signal->it_real_incr.tv64 = 0;
	173
bc1978d4	174	spin_unlock_irq(&tsk->sighand->siglock);
1da177e4 LT	175	break;
	176	case ITIMER_VIRTUAL:
	177	nval = timeval_to_cputime(&value->it_value);
	178	ninterval = timeval_to_cputime(&value->it_interval);
1da177e4 LT	179	spin_lock_irq(&tsk->sighand->siglock);
	180	cval = tsk->signal->it_virt_expires;
	181	cinterval = tsk->signal->it_virt_incr;
	182	if (!cputime_eq(cval, cputime_zero) \|\|
	183	!cputime_eq(nval, cputime_zero)) {
	184	if (cputime_gt(nval, cputime_zero))
	185	nval = cputime_add(nval,
	186	jiffies_to_cputime(1));
	187	set_process_cpu_timer(tsk, CPUCLOCK_VIRT,
	188	&nval, &cval);
	189	}
	190	tsk->signal->it_virt_expires = nval;
	191	tsk->signal->it_virt_incr = ninterval;
	192	spin_unlock_irq(&tsk->sighand->siglock);
1da177e4 LT	193	if (ovalue) {
	194	cputime_to_timeval(cval, &ovalue->it_value);
	195	cputime_to_timeval(cinterval, &ovalue->it_interval);
	196	}
	197	break;
	198	case ITIMER_PROF:
	199	nval = timeval_to_cputime(&value->it_value);
	200	ninterval = timeval_to_cputime(&value->it_interval);
1da177e4 LT	201	spin_lock_irq(&tsk->sighand->siglock);
	202	cval = tsk->signal->it_prof_expires;
	203	cinterval = tsk->signal->it_prof_incr;
	204	if (!cputime_eq(cval, cputime_zero) \|\|
	205	!cputime_eq(nval, cputime_zero)) {
	206	if (cputime_gt(nval, cputime_zero))
	207	nval = cputime_add(nval,
	208	jiffies_to_cputime(1));
	209	set_process_cpu_timer(tsk, CPUCLOCK_PROF,
	210	&nval, &cval);
	211	}
	212	tsk->signal->it_prof_expires = nval;
	213	tsk->signal->it_prof_incr = ninterval;
	214	spin_unlock_irq(&tsk->sighand->siglock);
1da177e4 LT	215	if (ovalue) {
	216	cputime_to_timeval(cval, &ovalue->it_value);
	217	cputime_to_timeval(cinterval, &ovalue->it_interval);
	218	}
	219	break;
	220	default:
	221	return -EINVAL;
	222	}
	223	return 0;
	224	}
	225
c08b8a49 TG	226	/**
	227	* alarm_setitimer - set alarm in seconds
	228	*
	229	* @seconds: number of seconds until alarm
	230	* 0 disables the alarm
	231	*
	232	* Returns the remaining time in seconds of a pending timer or 0 when
	233	* the timer is not active.
	234	*
	235	* On 32 bit machines the seconds value is limited to (INT_MAX/2) to avoid
	236	* negative timeval settings which would cause immediate expiry.
	237	*/
	238	unsigned int alarm_setitimer(unsigned int seconds)
	239	{
	240	struct itimerval it_new, it_old;
	241
	242	#if BITS_PER_LONG < 64
	243	if (seconds > INT_MAX)
	244	seconds = INT_MAX;
	245	#endif
	246	it_new.it_value.tv_sec = seconds;
	247	it_new.it_value.tv_usec = 0;
	248	it_new.it_interval.tv_sec = it_new.it_interval.tv_usec = 0;
	249
	250	do_setitimer(ITIMER_REAL, &it_new, &it_old);
	251
	252	/*
	253	* We can't return 0 if we have an alarm pending ... And we'd
	254	* better return too much than too little anyway
	255	*/
	256	if ((!it_old.it_value.tv_sec && it_old.it_value.tv_usec) \|\|
	257	it_old.it_value.tv_usec >= 500000)
	258	it_old.it_value.tv_sec++;
	259
	260	return it_old.it_value.tv_sec;
	261	}
	262
362e9c07 HC	263	SYSCALL_DEFINE3(setitimer, int, which, struct itimerval __user *, value,
362e9c07 HC	264	struct itimerval __user *, ovalue)
1da177e4 LT	265	{
	266	struct itimerval set_buffer, get_buffer;
	267	int error;
	268
	269	if (value) {
	270	if(copy_from_user(&set_buffer, value, sizeof(set_buffer)))
	271	return -EFAULT;
	272	} else
	273	memset((char *) &set_buffer, 0, sizeof(set_buffer));
	274
	275	error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL);
	276	if (error \|\| !ovalue)
	277	return error;
	278
	279	if (copy_to_user(ovalue, &get_buffer, sizeof(get_buffer)))
0719e370	280	return -EFAULT;
1da177e4 LT	281	return 0;
1da177e4 LT	282	}