[linux.git] / kernel / time / posix-clock.c

/*
 * posix-clock.c - support for dynamic clock devices
 *
 * Copyright (C) 2010 OMICRON electronics GmbH
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
#include <linux/device.h>
#include <linux/export.h>
#include <linux/file.h>
#include <linux/posix-clock.h>
#include <linux/slab.h>
#include <linux/syscalls.h>
#include <linux/uaccess.h>

static void delete_clock(struct kref *kref);

/*
 * Returns NULL if the posix_clock instance attached to 'fp' is old and stale.
 */
static struct posix_clock *get_posix_clock(struct file *fp)
{
	struct posix_clock *clk = fp->private_data;

	down_read(&clk->rwsem);

	if (!clk->zombie)
		return clk;

	up_read(&clk->rwsem);

	return NULL;
}

static void put_posix_clock(struct posix_clock *clk)
{
	up_read(&clk->rwsem);
}

static ssize_t posix_clock_read(struct file *fp, char __user *buf,
				size_t count, loff_t *ppos)
{
	struct posix_clock *clk = get_posix_clock(fp);
	int err = -EINVAL;

	if (!clk)
		return -ENODEV;

	if (clk->ops.read)
		err = clk->ops.read(clk, fp->f_flags, buf, count);

	put_posix_clock(clk);

	return err;
}

static unsigned int posix_clock_poll(struct file *fp, poll_table *wait)
{
	struct posix_clock *clk = get_posix_clock(fp);
	unsigned int result = 0;

	if (!clk)
		return POLLERR;

	if (clk->ops.poll)
		result = clk->ops.poll(clk, fp, wait);

	put_posix_clock(clk);

	return result;
}

static int posix_clock_fasync(int fd, struct file *fp, int on)
{
	struct posix_clock *clk = get_posix_clock(fp);
	int err = 0;

	if (!clk)
		return -ENODEV;

	if (clk->ops.fasync)
		err = clk->ops.fasync(clk, fd, fp, on);

	put_posix_clock(clk);

	return err;
}

static int posix_clock_mmap(struct file *fp, struct vm_area_struct *vma)
{
	struct posix_clock *clk = get_posix_clock(fp);
	int err = -ENODEV;

	if (!clk)
		return -ENODEV;

	if (clk->ops.mmap)
		err = clk->ops.mmap(clk, vma);

	put_posix_clock(clk);

	return err;
}

static long posix_clock_ioctl(struct file *fp,
			      unsigned int cmd, unsigned long arg)
{
	struct posix_clock *clk = get_posix_clock(fp);
	int err = -ENOTTY;

	if (!clk)
		return -ENODEV;

	if (clk->ops.ioctl)
		err = clk->ops.ioctl(clk, cmd, arg);

	put_posix_clock(clk);

	return err;
}

#ifdef CONFIG_COMPAT
static long posix_clock_compat_ioctl(struct file *fp,
				     unsigned int cmd, unsigned long arg)
{
	struct posix_clock *clk = get_posix_clock(fp);
	int err = -ENOTTY;

	if (!clk)
		return -ENODEV;

	if (clk->ops.ioctl)
		err = clk->ops.ioctl(clk, cmd, arg);

	put_posix_clock(clk);

	return err;
}
#endif

static int posix_clock_open(struct inode *inode, struct file *fp)
{
	int err;
	struct posix_clock *clk =
		container_of(inode->i_cdev, struct posix_clock, cdev);

	down_read(&clk->rwsem);

	if (clk->zombie) {
		err = -ENODEV;
		goto out;
	}
	if (clk->ops.open)
		err = clk->ops.open(clk, fp->f_mode);
	else
		err = 0;

	if (!err) {
		kref_get(&clk->kref);
		fp->private_data = clk;
	}
out:
	up_read(&clk->rwsem);
	return err;
}

static int posix_clock_release(struct inode *inode, struct file *fp)
{
	struct posix_clock *clk = fp->private_data;
	int err = 0;

	if (clk->ops.release)
		err = clk->ops.release(clk);

	kref_put(&clk->kref, delete_clock);

	fp->private_data = NULL;

	return err;
}

static const struct file_operations posix_clock_file_operations = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.read		= posix_clock_read,
	.poll		= posix_clock_poll,
	.unlocked_ioctl	= posix_clock_ioctl,
	.open		= posix_clock_open,
	.release	= posix_clock_release,
	.fasync		= posix_clock_fasync,
	.mmap		= posix_clock_mmap,
#ifdef CONFIG_COMPAT
	.compat_ioctl	= posix_clock_compat_ioctl,
#endif
};

int posix_clock_register(struct posix_clock *clk, dev_t devid)
{
	int err;

	kref_init(&clk->kref);
	init_rwsem(&clk->rwsem);

	cdev_init(&clk->cdev, &posix_clock_file_operations);
	clk->cdev.owner = clk->ops.owner;
	err = cdev_add(&clk->cdev, devid, 1);

	return err;
}
EXPORT_SYMBOL_GPL(posix_clock_register);

static void delete_clock(struct kref *kref)
{
	struct posix_clock *clk = container_of(kref, struct posix_clock, kref);

	if (clk->release)
		clk->release(clk);
}

void posix_clock_unregister(struct posix_clock *clk)
{
	cdev_del(&clk->cdev);

	down_write(&clk->rwsem);
	clk->zombie = true;
	up_write(&clk->rwsem);

	kref_put(&clk->kref, delete_clock);
}
EXPORT_SYMBOL_GPL(posix_clock_unregister);

struct posix_clock_desc {
	struct file *fp;
	struct posix_clock *clk;
};

static int get_clock_desc(const clockid_t id, struct posix_clock_desc *cd)
{
	struct file *fp = fget(CLOCKID_TO_FD(id));
	int err = -EINVAL;

	if (!fp)
		return err;

	if (fp->f_op->open != posix_clock_open || !fp->private_data)
		goto out;

	cd->fp = fp;
	cd->clk = get_posix_clock(fp);

	err = cd->clk ? 0 : -ENODEV;
out:
	if (err)
		fput(fp);
	return err;
}

static void put_clock_desc(struct posix_clock_desc *cd)
{
	put_posix_clock(cd->clk);
	fput(cd->fp);
}

static int pc_clock_adjtime(clockid_t id, struct timex *tx)
{
	struct posix_clock_desc cd;
	int err;

	err = get_clock_desc(id, &cd);
	if (err)
		return err;

	if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
		err = -EACCES;
		goto out;
	}

	if (cd.clk->ops.clock_adjtime)
		err = cd.clk->ops.clock_adjtime(cd.clk, tx);
	else
		err = -EOPNOTSUPP;
out:
	put_clock_desc(&cd);

	return err;
}

static int pc_clock_gettime(clockid_t id, struct timespec *ts)
{
	struct posix_clock_desc cd;
	int err;

	err = get_clock_desc(id, &cd);
	if (err)
		return err;

	if (cd.clk->ops.clock_gettime)
		err = cd.clk->ops.clock_gettime(cd.clk, ts);
	else
		err = -EOPNOTSUPP;

	put_clock_desc(&cd);

	return err;
}

static int pc_clock_getres(clockid_t id, struct timespec *ts)
{
	struct posix_clock_desc cd;
	int err;

	err = get_clock_desc(id, &cd);
	if (err)
		return err;

	if (cd.clk->ops.clock_getres)
		err = cd.clk->ops.clock_getres(cd.clk, ts);
	else
		err = -EOPNOTSUPP;

	put_clock_desc(&cd);

	return err;
}

static int pc_clock_settime(clockid_t id, const struct timespec *ts)
{
	struct posix_clock_desc cd;
	int err;

	err = get_clock_desc(id, &cd);
	if (err)
		return err;

	if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
		err = -EACCES;
		goto out;
	}

	if (cd.clk->ops.clock_settime)
		err = cd.clk->ops.clock_settime(cd.clk, ts);
	else
		err = -EOPNOTSUPP;
out:
	put_clock_desc(&cd);

	return err;
}

static int pc_timer_create(struct k_itimer *kit)
{
	clockid_t id = kit->it_clock;
	struct posix_clock_desc cd;
	int err;

	err = get_clock_desc(id, &cd);
	if (err)
		return err;

	if (cd.clk->ops.timer_create)
		err = cd.clk->ops.timer_create(cd.clk, kit);
	else
		err = -EOPNOTSUPP;

	put_clock_desc(&cd);

	return err;
}

static int pc_timer_delete(struct k_itimer *kit)
{
	clockid_t id = kit->it_clock;
	struct posix_clock_desc cd;
	int err;

	err = get_clock_desc(id, &cd);
	if (err)
		return err;

	if (cd.clk->ops.timer_delete)
		err = cd.clk->ops.timer_delete(cd.clk, kit);
	else
		err = -EOPNOTSUPP;

	put_clock_desc(&cd);

	return err;
}

static void pc_timer_gettime(struct k_itimer *kit, struct itimerspec *ts)
{
	clockid_t id = kit->it_clock;
	struct posix_clock_desc cd;

	if (get_clock_desc(id, &cd))
		return;

	if (cd.clk->ops.timer_gettime)
		cd.clk->ops.timer_gettime(cd.clk, kit, ts);

	put_clock_desc(&cd);
}

static int pc_timer_settime(struct k_itimer *kit, int flags,
			    struct itimerspec *ts, struct itimerspec *old)
{
	clockid_t id = kit->it_clock;
	struct posix_clock_desc cd;
	int err;

	err = get_clock_desc(id, &cd);
	if (err)
		return err;

	if (cd.clk->ops.timer_settime)
		err = cd.clk->ops.timer_settime(cd.clk, kit, flags, ts, old);
	else
		err = -EOPNOTSUPP;

	put_clock_desc(&cd);

	return err;
}

struct k_clock clock_posix_dynamic = {
	.clock_getres	= pc_clock_getres,
	.clock_set	= pc_clock_settime,
	.clock_get	= pc_clock_gettime,
	.clock_adj	= pc_clock_adjtime,
	.timer_create	= pc_timer_create,
	.timer_set	= pc_timer_settime,
	.timer_del	= pc_timer_delete,
	.timer_get	= pc_timer_gettime,
};
Commit	Line	Data
0606f422 RC	1	/*
	2	* posix-clock.c - support for dynamic clock devices
	3	*
	4	* Copyright (C) 2010 OMICRON electronics GmbH
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; either version 2 of the License, or
	9	* (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public License
	17	* along with this program; if not, write to the Free Software
	18	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	19	*/
	20	#include <linux/device.h>
6e5fdeed	21	#include <linux/export.h>
0606f422	22	#include <linux/file.h>
0606f422 RC	23	#include <linux/posix-clock.h>
	24	#include <linux/slab.h>
	25	#include <linux/syscalls.h>
	26	#include <linux/uaccess.h>
	27
	28	static void delete_clock(struct kref *kref);
	29
	30	/*
	31	* Returns NULL if the posix_clock instance attached to 'fp' is old and stale.
	32	*/
	33	static struct posix_clock get_posix_clock(struct file fp)
	34	{
	35	struct posix_clock *clk = fp->private_data;
	36
1791f881	37	down_read(&clk->rwsem);
0606f422 RC	38
	39	if (!clk->zombie)
	40	return clk;
	41
1791f881	42	up_read(&clk->rwsem);
0606f422 RC	43
	44	return NULL;
	45	}
	46
	47	static void put_posix_clock(struct posix_clock *clk)
	48	{
1791f881	49	up_read(&clk->rwsem);
0606f422 RC	50	}
	51
	52	static ssize_t posix_clock_read(struct file fp, char __user buf,
	53	size_t count, loff_t *ppos)
	54	{
	55	struct posix_clock *clk = get_posix_clock(fp);
	56	int err = -EINVAL;
	57
	58	if (!clk)
	59	return -ENODEV;
	60
	61	if (clk->ops.read)
	62	err = clk->ops.read(clk, fp->f_flags, buf, count);
	63
	64	put_posix_clock(clk);
	65
	66	return err;
	67	}
	68
	69	static unsigned int posix_clock_poll(struct file fp, poll_table wait)
	70	{
	71	struct posix_clock *clk = get_posix_clock(fp);
1b9f2372	72	unsigned int result = 0;
0606f422 RC	73
0606f422 RC	74	if (!clk)
1b9f2372	75	return POLLERR;
0606f422 RC	76
	77	if (clk->ops.poll)
	78	result = clk->ops.poll(clk, fp, wait);
	79
	80	put_posix_clock(clk);
	81
	82	return result;
	83	}
	84
	85	static int posix_clock_fasync(int fd, struct file *fp, int on)
	86	{
	87	struct posix_clock *clk = get_posix_clock(fp);
	88	int err = 0;
	89
	90	if (!clk)
	91	return -ENODEV;
	92
	93	if (clk->ops.fasync)
	94	err = clk->ops.fasync(clk, fd, fp, on);
	95
	96	put_posix_clock(clk);
	97
	98	return err;
	99	}
	100
	101	static int posix_clock_mmap(struct file fp, struct vm_area_struct vma)
	102	{
	103	struct posix_clock *clk = get_posix_clock(fp);
	104	int err = -ENODEV;
	105
	106	if (!clk)
	107	return -ENODEV;
	108
	109	if (clk->ops.mmap)
	110	err = clk->ops.mmap(clk, vma);
	111
	112	put_posix_clock(clk);
	113
	114	return err;
	115	}
	116
	117	static long posix_clock_ioctl(struct file *fp,
	118	unsigned int cmd, unsigned long arg)
	119	{
	120	struct posix_clock *clk = get_posix_clock(fp);
	121	int err = -ENOTTY;
	122
	123	if (!clk)
	124	return -ENODEV;
	125
	126	if (clk->ops.ioctl)
	127	err = clk->ops.ioctl(clk, cmd, arg);
	128
	129	put_posix_clock(clk);
	130
	131	return err;
	132	}
	133
	134	#ifdef CONFIG_COMPAT
	135	static long posix_clock_compat_ioctl(struct file *fp,
	136	unsigned int cmd, unsigned long arg)
	137	{
	138	struct posix_clock *clk = get_posix_clock(fp);
	139	int err = -ENOTTY;
140
141	if (!clk)
142	return -ENODEV;
143
144	if (clk->ops.ioctl)
145	err = clk->ops.ioctl(clk, cmd, arg);
146
147	put_posix_clock(clk);
148
149	return err;
150	}
151	#endif
152
153	static int posix_clock_open(struct inode inode, struct file fp)
154	{
155	int err;
156	struct posix_clock *clk =
157	container_of(inode->i_cdev, struct posix_clock, cdev);
158
1791f881	159	down_read(&clk->rwsem);
0606f422 RC	160
	161	if (clk->zombie) {
	162	err = -ENODEV;
	163	goto out;
	164	}
	165	if (clk->ops.open)
	166	err = clk->ops.open(clk, fp->f_mode);
	167	else
	168	err = 0;
	169
	170	if (!err) {
	171	kref_get(&clk->kref);
	172	fp->private_data = clk;
	173	}
	174	out:
1791f881	175	up_read(&clk->rwsem);
0606f422 RC	176	return err;
	177	}
	178
	179	static int posix_clock_release(struct inode inode, struct file fp)
	180	{
	181	struct posix_clock *clk = fp->private_data;
	182	int err = 0;
	183
	184	if (clk->ops.release)
	185	err = clk->ops.release(clk);
	186
	187	kref_put(&clk->kref, delete_clock);
	188
	189	fp->private_data = NULL;
	190
	191	return err;
	192	}
	193
	194	static const struct file_operations posix_clock_file_operations = {
	195	.owner = THIS_MODULE,
	196	.llseek = no_llseek,
	197	.read = posix_clock_read,
	198	.poll = posix_clock_poll,
	199	.unlocked_ioctl = posix_clock_ioctl,
	200	.open = posix_clock_open,
	201	.release = posix_clock_release,
	202	.fasync = posix_clock_fasync,
	203	.mmap = posix_clock_mmap,
	204	#ifdef CONFIG_COMPAT
	205	.compat_ioctl = posix_clock_compat_ioctl,
	206	#endif
	207	};
	208
	209	int posix_clock_register(struct posix_clock *clk, dev_t devid)
	210	{
	211	int err;
	212
	213	kref_init(&clk->kref);
1791f881	214	init_rwsem(&clk->rwsem);
0606f422 RC	215
	216	cdev_init(&clk->cdev, &posix_clock_file_operations);
	217	clk->cdev.owner = clk->ops.owner;
	218	err = cdev_add(&clk->cdev, devid, 1);
0606f422 RC	219
0606f422 RC	220	return err;
0606f422 RC	221	}
	222	EXPORT_SYMBOL_GPL(posix_clock_register);
	223
	224	static void delete_clock(struct kref *kref)
	225	{
	226	struct posix_clock *clk = container_of(kref, struct posix_clock, kref);
1791f881	227
0606f422 RC	228	if (clk->release)
	229	clk->release(clk);
	230	}
	231
	232	void posix_clock_unregister(struct posix_clock *clk)
	233	{
	234	cdev_del(&clk->cdev);
	235
1791f881	236	down_write(&clk->rwsem);
0606f422	237	clk->zombie = true;
1791f881	238	up_write(&clk->rwsem);
0606f422 RC	239
	240	kref_put(&clk->kref, delete_clock);
	241	}
	242	EXPORT_SYMBOL_GPL(posix_clock_unregister);
	243
	244	struct posix_clock_desc {
	245	struct file *fp;
	246	struct posix_clock *clk;
	247	};
	248
	249	static int get_clock_desc(const clockid_t id, struct posix_clock_desc *cd)
	250	{
	251	struct file *fp = fget(CLOCKID_TO_FD(id));
	252	int err = -EINVAL;
	253
	254	if (!fp)
	255	return err;
	256
	257	if (fp->f_op->open != posix_clock_open \|\| !fp->private_data)
	258	goto out;
	259
	260	cd->fp = fp;
	261	cd->clk = get_posix_clock(fp);
	262
	263	err = cd->clk ? 0 : -ENODEV;
	264	out:
	265	if (err)
	266	fput(fp);
	267	return err;
	268	}
	269
	270	static void put_clock_desc(struct posix_clock_desc *cd)
	271	{
	272	put_posix_clock(cd->clk);
	273	fput(cd->fp);
	274	}
	275
	276	static int pc_clock_adjtime(clockid_t id, struct timex *tx)
	277	{
	278	struct posix_clock_desc cd;
	279	int err;
	280
	281	err = get_clock_desc(id, &cd);
	282	if (err)
	283	return err;
	284
6e6823d1 TH	285	if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
	286	err = -EACCES;
	287	goto out;
	288	}
	289
0606f422 RC	290	if (cd.clk->ops.clock_adjtime)
	291	err = cd.clk->ops.clock_adjtime(cd.clk, tx);
	292	else
	293	err = -EOPNOTSUPP;
6e6823d1	294	out:
0606f422 RC	295	put_clock_desc(&cd);
	296
	297	return err;
	298	}
	299
	300	static int pc_clock_gettime(clockid_t id, struct timespec *ts)
	301	{
	302	struct posix_clock_desc cd;
	303	int err;
	304
	305	err = get_clock_desc(id, &cd);
	306	if (err)
	307	return err;
	308
	309	if (cd.clk->ops.clock_gettime)
	310	err = cd.clk->ops.clock_gettime(cd.clk, ts);
	311	else
	312	err = -EOPNOTSUPP;
	313
	314	put_clock_desc(&cd);
	315
	316	return err;
	317	}
	318
	319	static int pc_clock_getres(clockid_t id, struct timespec *ts)
	320	{
	321	struct posix_clock_desc cd;
	322	int err;
	323
	324	err = get_clock_desc(id, &cd);
	325	if (err)
	326	return err;
	327
	328	if (cd.clk->ops.clock_getres)
	329	err = cd.clk->ops.clock_getres(cd.clk, ts);
	330	else
	331	err = -EOPNOTSUPP;
	332
	333	put_clock_desc(&cd);
	334
	335	return err;
	336	}
	337
	338	static int pc_clock_settime(clockid_t id, const struct timespec *ts)
	339	{
	340	struct posix_clock_desc cd;
	341	int err;
	342
	343	err = get_clock_desc(id, &cd);
	344	if (err)
	345	return err;
	346
6e6823d1 TH	347	if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
	348	err = -EACCES;
	349	goto out;
	350	}
	351
0606f422 RC	352	if (cd.clk->ops.clock_settime)
	353	err = cd.clk->ops.clock_settime(cd.clk, ts);
	354	else
	355	err = -EOPNOTSUPP;
6e6823d1	356	out:
0606f422 RC	357	put_clock_desc(&cd);
	358
	359	return err;
	360	}
	361
	362	static int pc_timer_create(struct k_itimer *kit)
	363	{
	364	clockid_t id = kit->it_clock;
	365	struct posix_clock_desc cd;
	366	int err;
	367
	368	err = get_clock_desc(id, &cd);
	369	if (err)
	370	return err;
	371
	372	if (cd.clk->ops.timer_create)
	373	err = cd.clk->ops.timer_create(cd.clk, kit);
	374	else
	375	err = -EOPNOTSUPP;
	376
	377	put_clock_desc(&cd);
	378
	379	return err;
	380	}
	381
	382	static int pc_timer_delete(struct k_itimer *kit)
	383	{
	384	clockid_t id = kit->it_clock;
	385	struct posix_clock_desc cd;
	386	int err;
	387
	388	err = get_clock_desc(id, &cd);
	389	if (err)
	390	return err;
	391
	392	if (cd.clk->ops.timer_delete)
	393	err = cd.clk->ops.timer_delete(cd.clk, kit);
	394	else
	395	err = -EOPNOTSUPP;
	396
	397	put_clock_desc(&cd);
	398
	399	return err;
	400	}
	401
	402	static void pc_timer_gettime(struct k_itimer kit, struct itimerspec ts)
	403	{
	404	clockid_t id = kit->it_clock;
	405	struct posix_clock_desc cd;
	406
	407	if (get_clock_desc(id, &cd))
	408	return;
	409
	410	if (cd.clk->ops.timer_gettime)
	411	cd.clk->ops.timer_gettime(cd.clk, kit, ts);
	412
	413	put_clock_desc(&cd);
	414	}
	415
	416	static int pc_timer_settime(struct k_itimer *kit, int flags,
	417	struct itimerspec ts, struct itimerspec old)
	418	{
	419	clockid_t id = kit->it_clock;
	420	struct posix_clock_desc cd;
421	int err;
422
423	err = get_clock_desc(id, &cd);
424	if (err)
425	return err;
426
427	if (cd.clk->ops.timer_settime)
428	err = cd.clk->ops.timer_settime(cd.clk, kit, flags, ts, old);
429	else
430	err = -EOPNOTSUPP;
431
432	put_clock_desc(&cd);
433
434	return err;
435	}
436
437	struct k_clock clock_posix_dynamic = {
438	.clock_getres = pc_clock_getres,
439	.clock_set = pc_clock_settime,
440	.clock_get = pc_clock_gettime,
441	.clock_adj = pc_clock_adjtime,
442	.timer_create = pc_timer_create,
443	.timer_set = pc_timer_settime,
444	.timer_del = pc_timer_delete,
445	.timer_get = pc_timer_gettime,
446	};