/* *  inode.c - securityfs * *  Copyright (C) 2005 Greg Kroah-Hartman <gregkh@suse.de> * *	This program is free software; you can redistribute it and/or *	modify it under the terms of the GNU General Public License version *	2 as published by the Free Software Foundation. * *  Based on fs/debugfs/inode.c which had the following copyright notice: *    Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com> *    Copyright (C) 2004 IBM Inc. */ /* #define DEBUG */#include <linux/module.h>#include <linux/fs.h>#include <linux/mount.h>#include <linux/pagemap.h>#include <linux/init.h>#include <linux/namei.h>#include <linux/security.h>#include <linux/magic.h> static struct vfsmount *mount;static int mount_count; static int fill_super(struct super_block *sb, void *data, int silent){	static struct tree_descr files[] = {{""}}; 	return simple_fill_super(sb, SECURITYFS_MAGIC, files);} static struct dentry *get_sb(struct file_system_type *fs_type,		  int flags, const char *dev_name,		  void *data){	return mount_single(fs_type, flags, data, fill_super);} static struct file_system_type fs_type = {	.owner =	THIS_MODULE,	.name =		"securityfs",	.mount =	get_sb,	.kill_sb =	kill_litter_super,}; /** * securityfs_create_file - create a file in the securityfs filesystem * * @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 securityfs filesystem. * @data: a pointer to something that the caller will want to get to later *        on.  The inode.i_private pointer will point to this value on *        the open() call. * @fops: a pointer to a struct file_operations that should be used for *        this file. * * This is the basic "create a file" function for securityfs.  It allows for a * wide range of flexibility in creating a file, or a directory (if you * want to create a directory, the securityfs_create_dir() function is * recommended to be used instead). * * This function returns a pointer to a dentry if it succeeds.  This * pointer must be passed to the securityfs_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, the function will return * the error value (via ERR_PTR). * * If securityfs is not enabled in the kernel, the value %-ENODEV is * returned. */struct dentry *securityfs_create_file(const char *name, umode_t mode,				   struct dentry *parent, void *data,				   const struct file_operations *fops){	struct dentry *dentry;	int is_dir = S_ISDIR(mode);	struct inode *dir, *inode;	int error; 	if (!is_dir) {		BUG_ON(!fops);		mode = (mode & S_IALLUGO) | S_IFREG;	} 	pr_debug("securityfs: creating file '%s'\n",name); 	error = simple_pin_fs(&fs_type, &mount, &mount_count);	if (error)		return ERR_PTR(error); 	if (!parent)		parent = mount->mnt_root; 	dir = d_inode(parent); 	mutex_lock(&dir->i_mutex);	dentry = lookup_one_len(name, parent, strlen(name));	if (IS_ERR(dentry))		goto out; 	if (d_really_is_positive(dentry)) {		error = -EEXIST;		goto out1;	} 	inode = new_inode(dir->i_sb);	if (!inode) {		error = -ENOMEM;		goto out1;	} 	inode->i_ino = get_next_ino();	inode->i_mode = mode;	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;	inode->i_private = data;	if (is_dir) {		inode->i_op = &simple_dir_inode_operations;		inode->i_fop = &simple_dir_operations;		inc_nlink(inode);		inc_nlink(dir);	} else {		inode->i_fop = fops;	}	d_instantiate(dentry, inode);	dget(dentry);	mutex_unlock(&dir->i_mutex);	return dentry; out1:	dput(dentry);	dentry = ERR_PTR(error);out:	mutex_unlock(&dir->i_mutex);	simple_release_fs(&mount, &mount_count);	return dentry;}EXPORT_SYMBOL_GPL(securityfs_create_file); /** * securityfs_create_dir - create a directory in the securityfs filesystem * * @name: a pointer to a string containing the name of the directory to *        create. * @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 *          directory will be created in the root of the securityfs filesystem. * * This function creates a directory in securityfs with the given @name. * * This function returns a pointer to a dentry if it succeeds.  This * pointer must be passed to the securityfs_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 securityfs is not enabled in the kernel, the value %-ENODEV is * 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 *securityfs_create_dir(const char *name, struct dentry *parent){	return securityfs_create_file(name,				      S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,				      parent, NULL, NULL);}EXPORT_SYMBOL_GPL(securityfs_create_dir); /** * securityfs_remove - removes a file or directory from the securityfs filesystem * * @dentry: a pointer to a the dentry of the file or directory to be removed. * * This function removes a file or directory in securityfs that was previously * created with a call to another securityfs function (like * securityfs_create_file() or variants thereof.) * * This function is required to be called in order for the file to be * removed. No automatic cleanup of files will happen when a module is * removed; you are responsible here. */void securityfs_remove(struct dentry *dentry){	struct dentry *parent; 	if (!dentry || IS_ERR(dentry))		return; 	parent = dentry->d_parent;	if (!parent || d_really_is_negative(parent))		return; 	mutex_lock(&d_inode(parent)->i_mutex);	if (simple_positive(dentry)) {		if (d_is_dir(dentry))			simple_rmdir(d_inode(parent), dentry);		else			simple_unlink(d_inode(parent), dentry);		dput(dentry);	}	mutex_unlock(&d_inode(parent)->i_mutex);	simple_release_fs(&mount, &mount_count);}EXPORT_SYMBOL_GPL(securityfs_remove); static int __init securityfs_init(void){	int retval; 	retval = sysfs_create_mount_point(kernel_kobj, "security");	if (retval)		return retval; 	retval = register_filesystem(&fs_type);	if (retval)		sysfs_remove_mount_point(kernel_kobj, "security");	return retval;} core_initcall(securityfs_init);MODULE_LICENSE("GPL");