file.c

linux 内核源代码

 * This function will return a pointer to a dentry if it succeeds.  This
 * pointer must be passed to the debugfs_remove() function when the file is
 * to be removed (no automatic cleanup happens if your module is unloaded,
 * you are responsible here.)  If an error occurs, %NULL will be returned.
 *
 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
 * returned.  It is not wise to check for this value, but rather, check for
 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
 * code.
 */
struct dentry *debugfs_create_u64(const char *name, mode_t mode,
				 struct dentry *parent, u64 *value)
{
	return debugfs_create_file(name, mode, parent, value, &fops_u64);
}
EXPORT_SYMBOL_GPL(debugfs_create_u64);

DEFINE_SIMPLE_ATTRIBUTE(fops_x8, debugfs_u8_get, debugfs_u8_set, "0x%02llx\n");

DEFINE_SIMPLE_ATTRIBUTE(fops_x16, debugfs_u16_get, debugfs_u16_set, "0x%04llx\n");

DEFINE_SIMPLE_ATTRIBUTE(fops_x32, debugfs_u32_get, debugfs_u32_set, "0x%08llx\n");

/*
 * debugfs_create_x{8,16,32} - create a debugfs file that is used to read and write an unsigned {8,16,32}-bit value
 *
 * These functions are exactly the same as the above functions (but use a hex
 * output for the decimal challenged). For details look at the above unsigned
 * decimal functions.
 */

/**
 * debugfs_create_x8 - create a debugfs file that is used to read and write an unsigned 8-bit value
 * @name: a pointer to a string containing the name of the file to create.
 * @mode: the permission that the file should have
 * @parent: a pointer to the parent dentry for this file.  This should be a
 *          directory dentry if set.  If this parameter is %NULL, then the
 *          file will be created in the root of the debugfs filesystem.
 * @value: a pointer to the variable that the file should read to and write
 *         from.
 */
struct dentry *debugfs_create_x8(const char *name, mode_t mode,
				 struct dentry *parent, u8 *value)
{
	return debugfs_create_file(name, mode, parent, value, &fops_x8);
}
EXPORT_SYMBOL_GPL(debugfs_create_x8);

/**
 * debugfs_create_x16 - create a debugfs file that is used to read and write an unsigned 16-bit value
 * @name: a pointer to a string containing the name of the file to create.
 * @mode: the permission that the file should have
 * @parent: a pointer to the parent dentry for this file.  This should be a
 *          directory dentry if set.  If this parameter is %NULL, then the
 *          file will be created in the root of the debugfs filesystem.
 * @value: a pointer to the variable that the file should read to and write
 *         from.
 */
struct dentry *debugfs_create_x16(const char *name, mode_t mode,
				 struct dentry *parent, u16 *value)
{
	return debugfs_create_file(name, mode, parent, value, &fops_x16);
}
EXPORT_SYMBOL_GPL(debugfs_create_x16);

/**
 * debugfs_create_x32 - create a debugfs file that is used to read and write an unsigned 32-bit value
 * @name: a pointer to a string containing the name of the file to create.
 * @mode: the permission that the file should have
 * @parent: a pointer to the parent dentry for this file.  This should be a
 *          directory dentry if set.  If this parameter is %NULL, then the
 *          file will be created in the root of the debugfs filesystem.
 * @value: a pointer to the variable that the file should read to and write
 *         from.
 */
struct dentry *debugfs_create_x32(const char *name, mode_t mode,
				 struct dentry *parent, u32 *value)
{
	return debugfs_create_file(name, mode, parent, value, &fops_x32);
}
EXPORT_SYMBOL_GPL(debugfs_create_x32);

static ssize_t read_file_bool(struct file *file, char __user *user_buf,
			      size_t count, loff_t *ppos)
{
	char buf[3];
	u32 *val = file->private_data;
	
	if (*val)
		buf[0] = 'Y';
	else
		buf[0] = 'N';
	buf[1] = '\n';
	buf[2] = 0x00;
	return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
}

static ssize_t write_file_bool(struct file *file, const char __user *user_buf,
			       size_t count, loff_t *ppos)
{
	char buf[32];
	int buf_size;
	u32 *val = file->private_data;

	buf_size = min(count, (sizeof(buf)-1));
	if (copy_from_user(buf, user_buf, buf_size))
		return -EFAULT;

	switch (buf[0]) {
	case 'y':
	case 'Y':
	case '1':
		*val = 1;
		break;
	case 'n':
	case 'N':
	case '0':
		*val = 0;
		break;
	}
	
	return count;
}

static const struct file_operations fops_bool = {
	.read =		read_file_bool,
	.write =	write_file_bool,
	.open =		default_open,
};

/**
 * debugfs_create_bool - create a debugfs file that is used to read and write a boolean value
 * @name: a pointer to a string containing the name of the file to create.
 * @mode: the permission that the file should have
 * @parent: a pointer to the parent dentry for this file.  This should be a
 *          directory dentry if set.  If this parameter is %NULL, then the
 *          file will be created in the root of the debugfs filesystem.
 * @value: a pointer to the variable that the file should read to and write
 *         from.
 *
 * This function creates a file in debugfs with the given name that
 * contains the value of the variable @value.  If the @mode variable is so
 * set, it can be read from, and written to.
 *
 * This function will return a pointer to a dentry if it succeeds.  This
 * pointer must be passed to the debugfs_remove() function when the file is
 * to be removed (no automatic cleanup happens if your module is unloaded,
 * you are responsible here.)  If an error occurs, %NULL will be returned.
 *
 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
 * returned.  It is not wise to check for this value, but rather, check for
 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
 * code.
 */
struct dentry *debugfs_create_bool(const char *name, mode_t mode,
				   struct dentry *parent, u32 *value)
{
	return debugfs_create_file(name, mode, parent, value, &fops_bool);
}
EXPORT_SYMBOL_GPL(debugfs_create_bool);

static ssize_t read_file_blob(struct file *file, char __user *user_buf,
			      size_t count, loff_t *ppos)
{
	struct debugfs_blob_wrapper *blob = file->private_data;
	return simple_read_from_buffer(user_buf, count, ppos, blob->data,
			blob->size);
}

static const struct file_operations fops_blob = {
	.read =		read_file_blob,
	.open =		default_open,
};

/**
 * debugfs_create_blob - create a debugfs file that is used to read and write a binary blob
 * @name: a pointer to a string containing the name of the file to create.
 * @mode: the permission that the file should have
 * @parent: a pointer to the parent dentry for this file.  This should be a
 *          directory dentry if set.  If this parameter is %NULL, then the
 *          file will be created in the root of the debugfs filesystem.
 * @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer
 *        to the blob data and the size of the data.
 *
 * This function creates a file in debugfs with the given name that exports
 * @blob->data as a binary blob. If the @mode variable is so set it can be
 * read from. Writing is not supported.
 *
 * This function will return a pointer to a dentry if it succeeds.  This
 * pointer must be passed to the debugfs_remove() function when the file is
 * to be removed (no automatic cleanup happens if your module is unloaded,
 * you are responsible here.)  If an error occurs, %NULL will be returned.
 *
 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
 * returned.  It is not wise to check for this value, but rather, check for
 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
 * code.
 */
struct dentry *debugfs_create_blob(const char *name, mode_t mode,
				   struct dentry *parent,
				   struct debugfs_blob_wrapper *blob)
{
	return debugfs_create_file(name, mode, parent, blob, &fops_blob);
}
EXPORT_SYMBOL_GPL(debugfs_create_blob);