path: root/drivers/media/dvb-core/dmxdev.c

/*
 * dmxdev.c - DVB demultiplexer device
 *
 * Copyright (C) 2000 Ralph Metzler & Marcus Metzler
 *		      for convergence integrated media GmbH
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2.1
 * 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.
 *
 */

#define pr_fmt(fmt) "dmxdev: " fmt

#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/module.h>
#include <linux/poll.h>
#include <linux/ioctl.h>
#include <linux/wait.h>
#include <linux/uaccess.h>
#include "dmxdev.h"

static int debug;

module_param(debug, int, 0644);
MODULE_PARM_DESC(debug, "Turn on/off debugging (default:off).");

#define dprintk(fmt, arg...) do {					\
	if (debug)							\
		printk(KERN_DEBUG pr_fmt("%s: " fmt),			\
			__func__, ##arg);				\
} while (0)

static int dvb_dmxdev_buffer_write(struct dvb_ringbuffer *buf,
				   const u8 *src, size_t len)
{
	ssize_t free;

	if (!len)
		return 0;
	if (!buf->data)
		return 0;

	free = dvb_ringbuffer_free(buf);
	if (len > free) {
		dprintk("buffer overflow\n");
		return -EOVERFLOW;
	}

	return dvb_ringbuffer_write(buf, src, len);
}

static ssize_t dvb_dmxdev_buffer_read(struct dvb_ringbuffer *src,
				      int non_blocking, char __user *buf,
				      size_t count, loff_t *ppos)
{
	size_t todo;
	ssize_t avail;
	ssize_t ret = 0;

	if (!src->data)
		return 0;

	if (src->error) {
		ret = src->error;
		dvb_ringbuffer_flush(src);
		return ret;
	}

	for (todo = count; todo > 0; todo -= ret) {
		if (non_blocking && dvb_ringbuffer_empty(src)) {
			ret = -EWOULDBLOCK;
			break;
		}

		ret = wait_event_interruptible(src->queue,
					       !dvb_ringbuffer_empty(src) ||
					       (src->error != 0));
		if (ret < 0)
			break;

		if (src->error) {
			ret = src->error;
			dvb_ringbuffer_flush(src);
			break;
		}

		avail = dvb_ringbuffer_avail(src);
		if (avail > todo)
			avail = todo;

		ret = dvb_ringbuffer_read_user(src, buf, avail);
		if (ret < 0)
			break;

		buf += ret;
	}

	return (count - todo) ? (count - todo) : ret;
}

static struct dmx_frontend *get_fe(struct dmx_demux *demux, int type)
{
	struct list_head *head, *pos;

	head = demux->get_frontends(demux);
	if (!head)
		return NULL;
	list_for_each(pos, head)
		if (DMX_FE_ENTRY(pos)->source == type)
			return DMX_FE_ENTRY(pos);

	return NULL;
}

static int dvb_dvr_open(struct inode *inode,