path: root/sound/core/info.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Information interface for ALSA driver
 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
 */

#include <linux/init.h>
#include <linux/time.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/module.h>
#include <sound/core.h>
#include <sound/minors.h>
#include <sound/info.h>
#include <linux/utsname.h>
#include <linux/proc_fs.h>
#include <linux/mutex.h>
#include <stdarg.h>

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 void snd_info_disconnect(struct snd_info_entry *entry);

/*

 */

static struct snd_info_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 int alloc_info_private(struct snd_info_entry *entry,
			      struct snd_info_private_data **ret)
{
	struct snd_info_private_data *data;

	if (!entry || !entry->p)
		return -ENODEV;
	if (!try_module_get(entry->module))
		return -EFAULT;
	data = kzalloc(sizeof(*data), GFP_KERNEL);
	if (!data) {
		module_put(entry->module);
		return -ENOMEM;
	}
	data->entry = entry;
	*ret = data;
	return 0;
}

static bool valid_pos(loff_t pos, size_t count)
{
	if (pos < 0 || (long) pos != pos || (ssize_t) count < 0)
		return false;
	if ((unsigned long) pos + (unsigned long) count < (unsigned long) pos)
		return false;
	return true;
}

/*
 * file ops for binary proc files
 */
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 = -EINVAL, size;

	data = file->private_data;
	entry = data->entry;
	mutex_lock(&entry->access);
	if (entry->c.ops->llseek) {
		offset = entry->c.ops->llseek(entry,
					      data->file_private_data,
					      file, offset, orig);
		goto out;
	}

	size = entry->size;
	switch (orig) {
	case SEEK_SET:
		break;
	case SEEK_CUR:
		offset += file->f_pos;
		break;
	case SEEK_END:
		if (!size)
			goto out;
		offset += size;
		break;
	default:
		goto out;
	}
	if (offset < 0)
		goto out;
	if (size && offset > size)
		offset = size;
	file->f_pos = offset;
	ret = offset;
 out:
	mutex_unlock(&entry->access);
	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 = file->private_data;
	struct snd_info_entry *entry = data->entry;
	size_t size;
	loff_t pos;

	pos = *offset;
	if (!valid_pos(pos, count))
		return -EIO;
	if (pos >= entry->size)
		return 0;
	size = entry->size - pos;
	size = min(count, size);
	size = entry->c.ops->read(entry, data->file_private_data,
				  file, buffer, size, pos);
	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 = file->private_data;
	struct snd_info_entry *entry = data->entry;
	ssize_t size = 0;
	loff_t pos;

	pos = *offset;
	if (!valid_pos(pos, count))
		return -EIO;
	if (count > 0) {
		size_t maxsize = entry->size - pos;
		count = min(count, maxsize);
		size = entry->c.ops->write(entry, data->file_private_data,
					   file, buffer, count, pos);
	}
	if (size > 0)
		*offset = pos + size;
	return size;
}

static __poll_t snd_info_entry_poll(struct file *file, poll_table *wait)
{
	struct snd_info_private_data *data = file->private_data;
	struct snd_info_entry *entry = data->entry;
	__poll_t mask = 0;

	if (entry->c.ops->poll)
		return entry->c.ops->poll(entry,
					  data->file_private_data,
					  file, wait);
	if (entry->c.ops->read)
		mask |= EPOLLIN | EPOLLRDNORM;
	if (entry->c.ops->write)
		mask |= EPOLLOUT | EPOLLWRNORM;
	return mask;
}

static long snd_info_entry_ioctl(