[linux.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:
		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
 */
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);
		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>
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;
	57	case ITIMER_VIRTUAL:
	58	read_lock(&tasklist_lock);
	59	spin_lock_irq(&tsk->sighand->siglock);
	60	cval = tsk->signal->it_virt_expires;
	61	cinterval = tsk->signal->it_virt_incr;
	62	if (!cputime_eq(cval, cputime_zero)) {
	63	struct task_struct *t = tsk;
	64	cputime_t utime = tsk->signal->utime;
	65	do {
	66	utime = cputime_add(utime, t->utime);
	67	t = next_thread(t);
	68	} while (t != tsk);
	69	if (cputime_le(cval, utime)) { /* about to fire */
	70	cval = jiffies_to_cputime(1);
	71	} else {
	72	cval = cputime_sub(cval, utime);
	73	}
	74	}
	75	spin_unlock_irq(&tsk->sighand->siglock);
	76	read_unlock(&tasklist_lock);
	77	cputime_to_timeval(cval, &value->it_value);
	78	cputime_to_timeval(cinterval, &value->it_interval);
	79	break;
	80	case ITIMER_PROF:
	81	read_lock(&tasklist_lock);
	82	spin_lock_irq(&tsk->sighand->siglock);
	83	cval = tsk->signal->it_prof_expires;
	84	cinterval = tsk->signal->it_prof_incr;
	85	if (!cputime_eq(cval, cputime_zero)) {
	86	struct task_struct *t = tsk;
	87	cputime_t ptime = cputime_add(tsk->signal->utime,
	88	tsk->signal->stime);
	89	do {
	90	ptime = cputime_add(ptime,
	91	cputime_add(t->utime,
	92	t->stime));
	93	t = next_thread(t);
	94	} while (t != tsk);
	95	if (cputime_le(cval, ptime)) { /* about to fire */
	96	cval = jiffies_to_cputime(1);
	97	} else {
	98	cval = cputime_sub(cval, ptime);
	99	}
	100	}
	101	spin_unlock_irq(&tsk->sighand->siglock);
	102	read_unlock(&tasklist_lock);
	103	cputime_to_timeval(cval, &value->it_value);
	104	cputime_to_timeval(cinterval, &value->it_interval);
	105	break;
	106	default:
	107	return(-EINVAL);
	108	}
	109	return 0;
	110	}
	111
	112	asmlinkage long sys_getitimer(int which, struct itimerval __user *value)
	113	{
	114	int error = -EFAULT;
	115	struct itimerval get_buffer;
	116
	117	if (value) {
	118	error = do_getitimer(which, &get_buffer);
	119	if (!error &&
120	copy_to_user(value, &get_buffer, sizeof(get_buffer)))
121	error = -EFAULT;
122	}
123	return error;
124	}
125
1da177e4	126
2ff678b8 TG	127	/*
	128	* The timer is automagically restarted, when interval != 0
	129	*/
c9cb2e3d	130	enum hrtimer_restart it_real_fn(struct hrtimer *timer)
1da177e4	131	{
05cfb614	132	struct signal_struct *sig =
0719e370	133	container_of(timer, struct signal_struct, real_timer);
1da177e4	134
fea9d175	135	kill_pid_info(SIGALRM, SEND_SIG_PRIV, sig->leader_pid);
2ff678b8	136
2ff678b8	137	return HRTIMER_NORESTART;
1da177e4 LT	138	}
1da177e4 LT	139
7d99b7d6 TG	140	/*
	141	* Returns true if the timeval is in canonical form
	142	*/
	143	#define timeval_valid(t) \
	144	(((t)->tv_sec >= 0) && (((unsigned long) (t)->tv_usec) < USEC_PER_SEC))
	145
1da177e4 LT	146	int do_setitimer(int which, struct itimerval value, struct itimerval ovalue)
	147	{
	148	struct task_struct *tsk = current;
2ff678b8 TG	149	struct hrtimer *timer;
2ff678b8 TG	150	ktime_t expires;
1da177e4 LT	151	cputime_t cval, cinterval, nval, ninterval;
1da177e4 LT	152
7d99b7d6 TG	153	/*
7d99b7d6 TG	154	* Validate the timevals in value.
7d99b7d6	155	*/
35bab756 AB	156	if (!timeval_valid(&value->it_value) \|\|
	157	!timeval_valid(&value->it_interval))
	158	return -EINVAL;
7d99b7d6	159
1da177e4 LT	160	switch (which) {
1da177e4 LT	161	case ITIMER_REAL:
bc1978d4 TG	162	again:
bc1978d4 TG	163	spin_lock_irq(&tsk->sighand->siglock);
2ff678b8	164	timer = &tsk->signal->real_timer;
1da177e4	165	if (ovalue) {
2ff678b8 TG	166	ovalue->it_value = itimer_get_remtime(timer);
	167	ovalue->it_interval
	168	= ktime_to_timeval(tsk->signal->it_real_incr);
1da177e4	169	}
a16a1c09 TG	170	/* We are sharing ->siglock with it_real_fn() */
	171	if (hrtimer_try_to_cancel(timer) < 0) {
	172	spin_unlock_irq(&tsk->sighand->siglock);
	173	goto again;
	174	}
2ff678b8	175	expires = timeval_to_ktime(value->it_value);
8bfd9a7a TG	176	if (expires.tv64 != 0) {
	177	tsk->signal->it_real_incr =
	178	timeval_to_ktime(value->it_interval);
c9cb2e3d	179	hrtimer_start(timer, expires, HRTIMER_MODE_REL);
8bfd9a7a TG	180	} else
	181	tsk->signal->it_real_incr.tv64 = 0;
	182
bc1978d4	183	spin_unlock_irq(&tsk->sighand->siglock);
1da177e4 LT	184	break;
	185	case ITIMER_VIRTUAL:
	186	nval = timeval_to_cputime(&value->it_value);
	187	ninterval = timeval_to_cputime(&value->it_interval);
	188	read_lock(&tasklist_lock);
	189	spin_lock_irq(&tsk->sighand->siglock);
	190	cval = tsk->signal->it_virt_expires;
	191	cinterval = tsk->signal->it_virt_incr;
	192	if (!cputime_eq(cval, cputime_zero) \|\|
	193	!cputime_eq(nval, cputime_zero)) {
	194	if (cputime_gt(nval, cputime_zero))
	195	nval = cputime_add(nval,
	196	jiffies_to_cputime(1));
	197	set_process_cpu_timer(tsk, CPUCLOCK_VIRT,
	198	&nval, &cval);
	199	}
	200	tsk->signal->it_virt_expires = nval;
	201	tsk->signal->it_virt_incr = ninterval;
	202	spin_unlock_irq(&tsk->sighand->siglock);
	203	read_unlock(&tasklist_lock);
	204	if (ovalue) {
	205	cputime_to_timeval(cval, &ovalue->it_value);
	206	cputime_to_timeval(cinterval, &ovalue->it_interval);
	207	}
	208	break;
	209	case ITIMER_PROF:
	210	nval = timeval_to_cputime(&value->it_value);
	211	ninterval = timeval_to_cputime(&value->it_interval);
	212	read_lock(&tasklist_lock);
	213	spin_lock_irq(&tsk->sighand->siglock);
	214	cval = tsk->signal->it_prof_expires;
	215	cinterval = tsk->signal->it_prof_incr;
	216	if (!cputime_eq(cval, cputime_zero) \|\|
	217	!cputime_eq(nval, cputime_zero)) {
	218	if (cputime_gt(nval, cputime_zero))
	219	nval = cputime_add(nval,
	220	jiffies_to_cputime(1));
	221	set_process_cpu_timer(tsk, CPUCLOCK_PROF,
	222	&nval, &cval);
	223	}
	224	tsk->signal->it_prof_expires = nval;
	225	tsk->signal->it_prof_incr = ninterval;
	226	spin_unlock_irq(&tsk->sighand->siglock);
	227	read_unlock(&tasklist_lock);
	228	if (ovalue) {
	229	cputime_to_timeval(cval, &ovalue->it_value);
	230	cputime_to_timeval(cinterval, &ovalue->it_interval);
	231	}
	232	break;
	233	default:
	234	return -EINVAL;
	235	}
	236	return 0;
	237	}
	238
c08b8a49 TG	239	/**
	240	* alarm_setitimer - set alarm in seconds
	241	*
	242	* @seconds: number of seconds until alarm
	243	* 0 disables the alarm
	244	*
	245	* Returns the remaining time in seconds of a pending timer or 0 when
	246	* the timer is not active.
	247	*
	248	* On 32 bit machines the seconds value is limited to (INT_MAX/2) to avoid
	249	* negative timeval settings which would cause immediate expiry.
	250	*/
	251	unsigned int alarm_setitimer(unsigned int seconds)
	252	{
	253	struct itimerval it_new, it_old;
	254
	255	#if BITS_PER_LONG < 64
	256	if (seconds > INT_MAX)
	257	seconds = INT_MAX;
	258	#endif
	259	it_new.it_value.tv_sec = seconds;
	260	it_new.it_value.tv_usec = 0;
	261	it_new.it_interval.tv_sec = it_new.it_interval.tv_usec = 0;
	262
	263	do_setitimer(ITIMER_REAL, &it_new, &it_old);
	264
	265	/*
	266	* We can't return 0 if we have an alarm pending ... And we'd
	267	* better return too much than too little anyway
	268	*/
	269	if ((!it_old.it_value.tv_sec && it_old.it_value.tv_usec) \|\|
	270	it_old.it_value.tv_usec >= 500000)
	271	it_old.it_value.tv_sec++;
	272
	273	return it_old.it_value.tv_sec;
	274	}
	275
1da177e4 LT	276	asmlinkage long sys_setitimer(int which,
	277	struct itimerval __user *value,
	278	struct itimerval __user *ovalue)
	279	{
	280	struct itimerval set_buffer, get_buffer;
	281	int error;
	282
	283	if (value) {
	284	if(copy_from_user(&set_buffer, value, sizeof(set_buffer)))
	285	return -EFAULT;
	286	} else
	287	memset((char *) &set_buffer, 0, sizeof(set_buffer));
	288
	289	error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL);
	290	if (error \|\| !ovalue)
	291	return error;
	292
	293	if (copy_to_user(ovalue, &get_buffer, sizeof(get_buffer)))
0719e370	294	return -EFAULT;
1da177e4 LT	295	return 0;
1da177e4 LT	296	}