kernel/time/posix-clock.c - linux - Git at Google

 /*
  * 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,
 };
	/*
	* 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,
	};