sgfs.h

/*
 * Copyright (c) 1998-2015 Erez Zadok
 * Copyright (c) 2009	   Shrikar Archak
 * Copyright (c) 2003-2015 Stony Brook University
 * Copyright (c) 2003-2015 The Research Foundation of SUNY
 *
 * 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.
 */

#ifndef _SGFS_H_
#define _SGFS_H_

#include <linux/kernel.h>
#include <linux/dcache.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/seq_file.h>
#include <linux/statfs.h>
#include <linux/fs_stack.h>
#include <linux/magic.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/xattr.h>
#include <linux/exportfs.h>

#include <linux/string.h>
#include <asm-generic/errno-base.h>
#include <linux/scatterlist.h>
#include <linux/crypto.h>
#include <linux/ceph/types.h>
#include <crypto/skcipher.h>
#include <linux/time.h>
#include <linux/timekeeping.h>
#include <linux/completion.h>

/* the file system name */
#define SGFS_NAME "sgfs"

/* sgfs root inode number */
#define SGFS_ROOT_INO     1

#define SGFS_TRASH_ENC		"/.trash_encryptor"
#define SGFS_TRASH_DIR		"/.sg"		
#define RES	1074020608

/* useful for tracking code reachability */
#define UDBG printk(KERN_DEFAULT "DBG:%s:%s:%d\n", __FILE__, __func__, __LINE__)

/* operations vectors defined in specific files */
extern const struct file_operations sgfs_main_fops;
extern const struct file_operations sgfs_dir_fops;
extern const struct inode_operations sgfs_main_iops;
extern const struct inode_operations sgfs_dir_iops;
extern const struct inode_operations sgfs_symlink_iops;
extern const struct super_operations sgfs_sops;
extern const struct dentry_operations sgfs_dops;
extern const struct address_space_operations sgfs_aops, sgfs_dummy_aops;
extern const struct vm_operations_struct sgfs_vm_ops;
extern const struct export_operations sgfs_export_ops;

extern int sgfs_init_inode_cache(void);
extern void sgfs_destroy_inode_cache(void);
extern int sgfs_init_dentry_cache(void);
extern void sgfs_destroy_dentry_cache(void);
extern int new_dentry_private_data(struct dentry *dentry);
extern void free_dentry_private_data(struct dentry *dentry);
extern struct dentry *sgfs_lookup(struct inode *dir, struct dentry *dentry,
				    unsigned int flags);
extern struct inode *sgfs_iget(struct super_block *sb,
				 struct inode *lower_inode);
extern int sgfs_interpose(struct dentry *dentry, struct super_block *sb,
			    struct path *lower_path);
extern int kencrypt(const char *, int, char *,char *, int, int);

/* file private data */
struct sgfs_file_info {
	struct file *lower_file;
	const struct vm_operations_struct *lower_vm_ops;
};

/* sgfs inode data in memory */
struct sgfs_inode_info {
	struct inode *lower_inode;
	struct inode vfs_inode;
};

/* sgfs dentry data in memory */
struct sgfs_dentry_info {
	spinlock_t lock;	/* protects lower_path */
	struct path lower_path;
};

/* sgfs super-block data in memory */
struct sgfs_sb_info {
	struct super_block *lower_sb;
};

/* user defined struct to pass parameters at mount time */
struct sgfs_parameters {
	void *lower_path_name;
	char *encrypt_key;
};

/* user defined struct for encryption callback function*/
struct tcrypt_result {
	struct completion completion;
	int err;
};

/*Buffer size for encryption and decryption tasks*/
#define	BUFFER_SIZE	16

/*
 * inode to private data
 *
 * Since we use containers and the struct inode is _inside_ the
 * sgfs_inode_info structure, SGFS_I will always (given a non-NULL
 * inode pointer), return a valid non-NULL pointer.
 */
static inline struct sgfs_inode_info *SGFS_I(const struct inode *inode)
{
	return container_of(inode, struct sgfs_inode_info, vfs_inode);
}

/* dentry to private data */
#define SGFS_D(dent) ((struct sgfs_dentry_info *)(dent)->d_fsdata)

/* superblock to private data */
#define SGFS_SB(super) ((struct sgfs_sb_info *)(super)->s_fs_info)

/* file to private Data */
#define SGFS_F(file) ((struct sgfs_file_info *)((file)->private_data))

/* file to lower file */
static inline struct file *sgfs_lower_file(const struct file *f)
{
	return SGFS_F(f)->lower_file;
}

static inline void sgfs_set_lower_file(struct file *f, struct file *val)
{
	SGFS_F(f)->lower_file = val;
}

/* inode to lower inode. */
static inline struct inode *sgfs_lower_inode(const struct inode *i)
{
	return SGFS_I(i)->lower_inode;
}

static inline void sgfs_set_lower_inode(struct inode *i, struct inode *val)
{
	SGFS_I(i)->lower_inode = val;
}

/* superblock to lower superblock */
static inline struct super_block *sgfs_lower_super(
	const struct super_block *sb)
{
	return SGFS_SB(sb)->lower_sb;
}

static inline void sgfs_set_lower_super(struct super_block *sb,
					  struct super_block *val)
{
	SGFS_SB(sb)->lower_sb = val;
}

/* path based (dentry/mnt) macros */
static inline void pathcpy(struct path *dst, const struct path *src)
{
	dst->dentry = src->dentry;
	dst->mnt = src->mnt;
}
/* Returns struct path.  Caller must path_put it. */
static inline void sgfs_get_lower_path(const struct dentry *dent,
					 struct path *lower_path)
{
	spin_lock(&SGFS_D(dent)->lock);
	pathcpy(lower_path, &SGFS_D(dent)->lower_path);
	path_get(lower_path);
	spin_unlock(&SGFS_D(dent)->lock);
	return;
}
static inline void sgfs_put_lower_path(const struct dentry *dent,
					 struct path *lower_path)
{
	path_put(lower_path);
	return;
}
static inline void sgfs_set_lower_path(const struct dentry *dent,
					 struct path *lower_path)
{
	spin_lock(&SGFS_D(dent)->lock);
	pathcpy(&SGFS_D(dent)->lower_path, lower_path);
	spin_unlock(&SGFS_D(dent)->lock);
	return;
}
static inline void sgfs_reset_lower_path(const struct dentry *dent)
{
	spin_lock(&SGFS_D(dent)->lock);
	SGFS_D(dent)->lower_path.dentry = NULL;
	SGFS_D(dent)->lower_path.mnt = NULL;
	spin_unlock(&SGFS_D(dent)->lock);
	return;
}
static inline void sgfs_put_reset_lower_path(const struct dentry *dent)
{
	struct path lower_path;
	spin_lock(&SGFS_D(dent)->lock);
	pathcpy(&lower_path, &SGFS_D(dent)->lower_path);
	SGFS_D(dent)->lower_path.dentry = NULL;
	SGFS_D(dent)->lower_path.mnt = NULL;
	spin_unlock(&SGFS_D(dent)->lock);
	path_put(&lower_path);
	return;
}

/* locking helpers */
static inline struct dentry *lock_parent(struct dentry *dentry)
{
	struct dentry *dir = dget_parent(dentry);
	inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
	return dir;
}

static inline void unlock_dir(struct dentry *dir)
{
	inode_unlock(d_inode(dir));
	dput(dir);
}
#endif	/* not _SGFS_H_ */