info.c

linux 内核源代码

/*
 *  Information interface for ALSA driver
 *  Copyright (c) by Jaroslav Kysela <[e-mail]>
 *
 *
 *   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 */

#include <sound/driver.h>
#include <linux/init.h>
#include <linux/time.h>
#include <linux/smp_lock.h>
#include <linux/string.h>
#include <sound/core.h>
#include <sound/minors.h>
#include <sound/info.h>
#include <sound/version.h>
#include <linux/proc_fs.h>
#include <linux/mutex.h>
#include <stdarg.h>

/*
 *
 */

#ifdef CONFIG_PROC_FS

int snd_info_check_reserved_words(const char *str)
{
	static char *reserved[] =
	{
		"version",
		"meminfo",
		"memdebug",
		"detect",
		"devices",
		"oss",
		"cards",
		"timers",
		"synth",
		"pcm",
		"seq",
		NULL
	};
	char **xstr = reserved;

	while (*xstr) {
		if (!strcmp(*xstr, str))
			return 0;
		xstr++;
	}
	if (!strncmp(str, "card", 4))
		return 0;
	return 1;
}

static DEFINE_MUTEX(info_mutex);

struct snd_info_private_data {
	struct snd_info_buffer *rbuffer;
	struct snd_info_buffer *wbuffer;
	struct snd_info_entry *entry;
	void *file_private_data;
};

static int snd_info_version_init(void);
static int snd_info_version_done(void);
static void snd_info_disconnect(struct snd_info_entry *entry);


/* resize the proc r/w buffer */
static int resize_info_buffer(struct snd_info_buffer *buffer,
			      unsigned int nsize)
{
	char *nbuf;

	nsize = PAGE_ALIGN(nsize);
	nbuf = kmalloc(nsize, GFP_KERNEL);
	if (! nbuf)
		return -ENOMEM;

	memcpy(nbuf, buffer->buffer, buffer->len);
	kfree(buffer->buffer);
	buffer->buffer = nbuf;
	buffer->len = nsize;
	return 0;
}

/**
 * snd_iprintf - printf on the procfs buffer
 * @buffer: the procfs buffer
 * @fmt: the printf format
 *
 * Outputs the string on the procfs buffer just like printf().
 *
 * Returns the size of output string.
 */
int snd_iprintf(struct snd_info_buffer *buffer, char *fmt,...)
{
	va_list args;
	int len, res;
	int err = 0;

	might_sleep();
	if (buffer->stop || buffer->error)
		return 0;
	len = buffer->len - buffer->size;
	va_start(args, fmt);
	for (;;) {
		va_list ap;
		va_copy(ap, args);
		res = vsnprintf(buffer->buffer + buffer->curr, len, fmt, ap);
		va_end(ap);
		if (res < len)
			break;
		err = resize_info_buffer(buffer, buffer->len + PAGE_SIZE);
		if (err < 0)
			break;
		len = buffer->len - buffer->size;
	}
	va_end(args);

	if (err < 0)
		return err;
	buffer->curr += res;
	buffer->size += res;
	return res;
}

EXPORT_SYMBOL(snd_iprintf);

/*

 */

static struct proc_dir_entry *snd_proc_root;
struct snd_info_entry *snd_seq_root;
EXPORT_SYMBOL(snd_seq_root);

#ifdef CONFIG_SND_OSSEMUL
struct snd_info_entry *snd_oss_root;
#endif

static inline void snd_info_entry_prepare(struct proc_dir_entry *de)
{
	de->owner = THIS_MODULE;
}

static void snd_remove_proc_entry(struct proc_dir_entry *parent,
				  struct proc_dir_entry *de)
{
	if (de)
		remove_proc_entry(de->name, parent);
}

static loff_t snd_info_entry_llseek(struct file *file, loff_t offset, int orig)
{
	struct snd_info_private_data *data;
	struct snd_info_entry *entry;
	loff_t ret;

	data = file->private_data;
	entry = data->entry;
	lock_kernel();
	switch (entry->content) {
	case SNDRV_INFO_CONTENT_TEXT:
		switch (orig) {
		case SEEK_SET:
			file->f_pos = offset;
			ret = file->f_pos;
			goto out;
		case SEEK_CUR:
			file->f_pos += offset;
			ret = file->f_pos;
			goto out;
		case SEEK_END:
		default:
			ret = -EINVAL;
			goto out;
		}
		break;
	case SNDRV_INFO_CONTENT_DATA:
		if (entry->c.ops->llseek) {
			ret = entry->c.ops->llseek(entry,
						    data->file_private_data,
						    file, offset, orig);
			goto out;
		}
		break;
	}
	ret = -ENXIO;
out:
	unlock_kernel();
	return ret;
}

static ssize_t snd_info_entry_read(struct file *file, char __user *buffer,
				   size_t count, loff_t * offset)
{
	struct snd_info_private_data *data;
	struct snd_info_entry *entry;
	struct snd_info_buffer *buf;
	size_t size = 0;
	loff_t pos;

	data = file->private_data;
	snd_assert(data != NULL, return -ENXIO);
	pos = *offset;
	if (pos < 0 || (long) pos != pos || (ssize_t) count < 0)
		return -EIO;
	if ((unsigned long) pos + (unsigned long) count < (unsigned long) pos)
		return -EIO;
	entry = data->entry;
	switch (entry->content) {
	case SNDRV_INFO_CONTENT_TEXT:
		buf = data->rbuffer;
		if (buf == NULL)
			return -EIO;
		if (pos >= buf->size)
			return 0;
		size = buf->size - pos;
		size = min(count, size);
		if (copy_to_user(buffer, buf->buffer + pos, size))
			return -EFAULT;
		break;
	case SNDRV_INFO_CONTENT_DATA:
		if (entry->c.ops->read)
			size = entry->c.ops->read(entry,
						  data->file_private_data,
						  file, buffer, count, pos);
		break;
	}
	if ((ssize_t) size > 0)
		*offset = pos + size;
	return size;
}

static ssize_t snd_info_entry_write(struct file *file, const char __user *buffer,
				    size_t count, loff_t * offset)
{
	struct snd_info_private_data *data;
	struct snd_info_entry *entry;
	struct snd_info_buffer *buf;
	ssize_t size = 0;
	loff_t pos;

	data = file->private_data;
	snd_assert(data != NULL, return -ENXIO);
	entry = data->entry;
	pos = *offset;
	if (pos < 0 || (long) pos != pos || (ssize_t) count < 0)
		return -EIO;
	if ((unsigned long) pos + (unsigned long) count < (unsigned long) pos)
		return -EIO;
	switch (entry->content) {
	case SNDRV_INFO_CONTENT_TEXT:
		buf = data->wbuffer;
		if (buf == NULL)
			return -EIO;
		mutex_lock(&entry->access);
		if (pos + count >= buf->len) {
			if (resize_info_buffer(buf, pos + count)) {
				mutex_unlock(&entry->access);
				return -ENOMEM;
			}
		}
		if (copy_from_user(buf->buffer + pos, buffer, count)) {
			mutex_unlock(&entry->access);
			return -EFAULT;
		}
		buf->size = pos + count;
		mutex_unlock(&entry->access);
		size = count;
		break;
	case SNDRV_INFO_CONTENT_DATA:
		if (entry->c.ops->write)
			size = entry->c.ops->write(entry,
						   data->file_private_data,
						   file, buffer, count, pos);
		break;
	}
	if ((ssize_t) size > 0)
		*offset = pos + size;
	return size;
}

static int snd_info_entry_open(struct inode *inode, struct file *file)
{
	struct snd_info_entry *entry;
	struct snd_info_private_data *data;
	struct snd_info_buffer *buffer;
	struct proc_dir_entry *p;
	int mode, err;

	mutex_lock(&info_mutex);
	p = PDE(inode);
	entry = p == NULL ? NULL : (struct snd_info_entry *)p->data;
	if (entry == NULL || ! entry->p) {
		mutex_unlock(&info_mutex);
		return -ENODEV;
	}
	if (!try_module_get(entry->module)) {
		err = -EFAULT;
		goto __error1;
	}
	mode = file->f_flags & O_ACCMODE;
	if (mode == O_RDONLY || mode == O_RDWR) {
		if ((entry->content == SNDRV_INFO_CONTENT_DATA &&
		     entry->c.ops->read == NULL)) {
		    	err = -ENODEV;
		    	goto __error;
		}
	}
	if (mode == O_WRONLY || mode == O_RDWR) {
		if ((entry->content == SNDRV_INFO_CONTENT_DATA &&
		     entry->c.ops->write == NULL)) {
		    	err = -ENODEV;
		    	goto __error;
		}
	}
	data = kzalloc(sizeof(*data), GFP_KERNEL);
	if (data == NULL) {
		err = -ENOMEM;
		goto __error;
	}
	data->entry = entry;
	switch (entry->content) {
	case SNDRV_INFO_CONTENT_TEXT:
		if (mode == O_RDONLY || mode == O_RDWR) {
			buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
			if (buffer == NULL)
				goto __nomem;
			data->rbuffer = buffer;
			buffer->len = PAGE_SIZE;
			buffer->buffer = kmalloc(buffer->len, GFP_KERNEL);
			if (buffer->buffer == NULL)
				goto __nomem;
		}
		if (mode == O_WRONLY || mode == O_RDWR) {
			buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
			if (buffer == NULL)
				goto __nomem;
			data->wbuffer = buffer;
			buffer->len = PAGE_SIZE;
			buffer->buffer = kmalloc(buffer->len, GFP_KERNEL);
			if (buffer->buffer == NULL)
				goto __nomem;
		}
		break;
	case SNDRV_INFO_CONTENT_DATA:	/* data */
		if (entry->c.ops->open) {
			if ((err = entry->c.ops->open(entry, mode,
						      &data->file_private_data)) < 0) {
				kfree(data);
				goto __error;
			}
		}
		break;
	}
	file->private_data = data;
	mutex_unlock(&info_mutex);
	if (entry->content == SNDRV_INFO_CONTENT_TEXT &&
	    (mode == O_RDONLY || mode == O_RDWR)) {
		if (entry->c.text.read) {
			mutex_lock(&entry->access);
			entry->c.text.read(entry, data->rbuffer);
			mutex_unlock(&entry->access);
		}
	}
	return 0;

 __nomem:
	if (data->rbuffer) {
		kfree(data->rbuffer->buffer);
		kfree(data->rbuffer);
	}
	if (data->wbuffer) {
		kfree(data->wbuffer->buffer);
		kfree(data->wbuffer);
	}
	kfree(data);
	err = -ENOMEM;
      __error:
	module_put(entry->module);
      __error1:
	mutex_unlock(&info_mutex);
	return err;
}

static int snd_info_entry_release(struct inode *inode, struct file *file)
{
	struct snd_info_entry *entry;
	struct snd_info_private_data *data;
	int mode;

	mode = file->f_flags & O_ACCMODE;
	data = file->private_data;
	entry = data->entry;
	switch (entry->content) {
	case SNDRV_INFO_CONTENT_TEXT:
		if (data->rbuffer) {
			kfree(data->rbuffer->buffer);
			kfree(data->rbuffer);
		}
		if (data->wbuffer) {
			if (entry->c.text.write) {
				entry->c.text.write(entry, data->wbuffer);
				if (data->wbuffer->error) {
					snd_printk(KERN_WARNING "data write error to %s (%i)\n",
						entry->name,
						data->wbuffer->error);
				}
			}
			kfree(data->wbuffer->buffer);
			kfree(data->wbuffer);
		}
		break;
	case SNDRV_INFO_CONTENT_DATA:
		if (entry->c.ops->release)
			entry->c.ops->release(entry, mode,
					      data->file_private_data);
		break;
	}
	module_put(entry->module);
	kfree(data);
	return 0;
}

static unsigned int snd_info_entry_poll(struct file *file, poll_table * wait)
{
	struct snd_info_private_data *data;
	struct snd_info_entry *entry;
	unsigned int mask;

	data = file->private_data;
	if (data == NULL)
		return 0;
	entry = data->entry;
	mask = 0;
	switch (entry->content) {
	case SNDRV_INFO_CONTENT_DATA:
		if (entry->c.ops->poll)
			return entry->c.ops->poll(entry,
						  data->file_private_data,
						  file, wait);
		if (entry->c.ops->read)
			mask |= POLLIN | POLLRDNORM;
		if (entry->c.ops->write)
			mask |= POLLOUT | POLLWRNORM;
		break;
	}
	return mask;
}

static long snd_info_entry_ioctl(struct file *file, unsigned int cmd,
				unsigned long arg)
{
	struct snd_info_private_data *data;
	struct snd_info_entry *entry;

	data = file->private_data;
	if (data == NULL)
		return 0;
	entry = data->entry;
	switch (entry->content) {
	case SNDRV_INFO_CONTENT_DATA:
		if (entry->c.ops->ioctl)
			return entry->c.ops->ioctl(entry,
						   data->file_private_data,
						   file, cmd, arg);
		break;
	}
	return -ENOTTY;
}

static int snd_info_entry_mmap(struct file *file, struct vm_area_struct *vma)
{
	struct inode *inode = file->f_path.dentry->d_inode;
	struct snd_info_private_data *data;
	struct snd_info_entry *entry;

	data = file->private_data;
	if (data == NULL)
		return 0;
	entry = data->entry;
	switch (entry->content) {
	case SNDRV_INFO_CONTENT_DATA:
		if (entry->c.ops->mmap)
			return entry->c.ops->mmap(entry,
						  data->file_private_data,
						  inode, file, vma);
		break;