[mirror_ubuntu-zesty-kernel.git] / include / linux / posix_acl.h

/*
  File: linux/posix_acl.h

  (C) 2002 Andreas Gruenbacher, <a.gruenbacher@computer.org>
*/


#ifndef __LINUX_POSIX_ACL_H
#define __LINUX_POSIX_ACL_H

#include <linux/bug.h>
#include <linux/slab.h>
#include <linux/rcupdate.h>

#define ACL_UNDEFINED_ID	(-1)

/* a_type field in acl_user_posix_entry_t */
#define ACL_TYPE_ACCESS		(0x8000)
#define ACL_TYPE_DEFAULT	(0x4000)

/* e_tag entry in struct posix_acl_entry */
#define ACL_USER_OBJ		(0x01)
#define ACL_USER		(0x02)
#define ACL_GROUP_OBJ		(0x04)
#define ACL_GROUP		(0x08)
#define ACL_MASK		(0x10)
#define ACL_OTHER		(0x20)

/* permissions in the e_perm field */
#define ACL_READ		(0x04)
#define ACL_WRITE		(0x02)
#define ACL_EXECUTE		(0x01)
//#define ACL_ADD		(0x08)
//#define ACL_DELETE		(0x10)

struct posix_acl_entry {
	short			e_tag;
	unsigned short		e_perm;
	unsigned int		e_id;
};

struct posix_acl {
	union {
		atomic_t		a_refcount;
		struct rcu_head		a_rcu;
	};
	unsigned int		a_count;
	struct posix_acl_entry	a_entries[0];
};

#define FOREACH_ACL_ENTRY(pa, acl, pe) \
	for(pa=(acl)->a_entries, pe=pa+(acl)->a_count; pa<pe; pa++)


/*
 * Duplicate an ACL handle.
 */
static inline struct posix_acl *
posix_acl_dup(struct posix_acl *acl)
{
	if (acl)
		atomic_inc(&acl->a_refcount);
	return acl;
}

/*
 * Free an ACL handle.
 */
static inline void
posix_acl_release(struct posix_acl *acl)
{
	if (acl && atomic_dec_and_test(&acl->a_refcount))
		kfree_rcu(acl, a_rcu);
}


/* posix_acl.c */

extern void posix_acl_init(struct posix_acl *, int);
extern struct posix_acl *posix_acl_alloc(int, gfp_t);
extern int posix_acl_valid(const struct posix_acl *);
extern int posix_acl_permission(struct inode *, const struct posix_acl *, int);
extern struct posix_acl *posix_acl_from_mode(umode_t, gfp_t);
extern int posix_acl_equiv_mode(const struct posix_acl *, umode_t *);
extern int posix_acl_create(struct posix_acl **, gfp_t, umode_t *);
extern int posix_acl_chmod(struct posix_acl **, gfp_t, umode_t);

extern struct posix_acl *get_posix_acl(struct inode *, int);
extern int set_posix_acl(struct inode *, int, struct posix_acl *);

#ifdef CONFIG_FS_POSIX_ACL
static inline struct posix_acl **acl_by_type(struct inode *inode, int type)
{
	switch (type) {
	case ACL_TYPE_ACCESS:
		return &inode->i_acl;
	case ACL_TYPE_DEFAULT:
		return &inode->i_default_acl;
	default:
		BUG();
	}
}

static inline struct posix_acl *get_cached_acl(struct inode *inode, int type)
{
	struct posix_acl **p = acl_by_type(inode, type);
	struct posix_acl *acl = ACCESS_ONCE(*p);
	if (acl) {
		spin_lock(&inode->i_lock);
		acl = *p;
		if (acl != ACL_NOT_CACHED)
			acl = posix_acl_dup(acl);
		spin_unlock(&inode->i_lock);
	}
	return acl;
}

static inline struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type)
{
	return rcu_dereference(*acl_by_type(inode, type));
}

static inline void set_cached_acl(struct inode *inode,
				  int type,
				  struct posix_acl *acl)
{
	struct posix_acl **p = acl_by_type(inode, type);
	struct posix_acl *old;
	spin_lock(&inode->i_lock);
	old = *p;
	rcu_assign_pointer(*p, posix_acl_dup(acl));
	spin_unlock(&inode->i_lock);
	if (old != ACL_NOT_CACHED)
		posix_acl_release(old);
}

static inline void forget_cached_acl(struct inode *inode, int type)
{
	struct posix_acl **p = acl_by_type(inode, type);
	struct posix_acl *old;
	spin_lock(&inode->i_lock);
	old = *p;
	*p = ACL_NOT_CACHED;
	spin_unlock(&inode->i_lock);
	if (old != ACL_NOT_CACHED)
		posix_acl_release(old);
}

static inline void forget_all_cached_acls(struct inode *inode)
{
	struct posix_acl *old_access, *old_default;
	spin_lock(&inode->i_lock);
	old_access = inode->i_acl;
	old_default = inode->i_default_acl;
	inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
	spin_unlock(&inode->i_lock);
	if (old_access != ACL_NOT_CACHED)
		posix_acl_release(old_access);
	if (old_default != ACL_NOT_CACHED)
		posix_acl_release(old_default);
}
#endif

static inline void cache_no_acl(struct inode *inode)
{
#ifdef CONFIG_FS_POSIX_ACL
	inode->i_acl = NULL;
	inode->i_default_acl = NULL;
#endif
}

#endif  /* __LINUX_POSIX_ACL_H */
Commit	Line	Data
1da177e4 LT	1	/*
	2	File: linux/posix_acl.h
	3
	4	(C) 2002 Andreas Gruenbacher, <a.gruenbacher@computer.org>
	5	*/
	6
	7
	8	#ifndef __LINUX_POSIX_ACL_H
	9	#define __LINUX_POSIX_ACL_H
	10
187f1882	11	#include <linux/bug.h>
1da177e4	12	#include <linux/slab.h>
3567866b	13	#include <linux/rcupdate.h>
1da177e4 LT	14
	15	#define ACL_UNDEFINED_ID (-1)
	16
	17	/* a_type field in acl_user_posix_entry_t */
	18	#define ACL_TYPE_ACCESS (0x8000)
	19	#define ACL_TYPE_DEFAULT (0x4000)
	20
	21	/* e_tag entry in struct posix_acl_entry */
	22	#define ACL_USER_OBJ (0x01)
	23	#define ACL_USER (0x02)
	24	#define ACL_GROUP_OBJ (0x04)
	25	#define ACL_GROUP (0x08)
	26	#define ACL_MASK (0x10)
	27	#define ACL_OTHER (0x20)
	28
	29	/* permissions in the e_perm field */
	30	#define ACL_READ (0x04)
	31	#define ACL_WRITE (0x02)
	32	#define ACL_EXECUTE (0x01)
	33	//#define ACL_ADD (0x08)
	34	//#define ACL_DELETE (0x10)
	35
	36	struct posix_acl_entry {
	37	short e_tag;
	38	unsigned short e_perm;
	39	unsigned int e_id;
	40	};
	41
	42	struct posix_acl {
3567866b AV	43	union {
	44	atomic_t a_refcount;
	45	struct rcu_head a_rcu;
	46	};
1da177e4 LT	47	unsigned int a_count;
	48	struct posix_acl_entry a_entries[0];
	49	};
	50
	51	#define FOREACH_ACL_ENTRY(pa, acl, pe) \
	52	for(pa=(acl)->a_entries, pe=pa+(acl)->a_count; pa<pe; pa++)
	53
	54
	55	/*
	56	* Duplicate an ACL handle.
	57	*/
	58	static inline struct posix_acl *
	59	posix_acl_dup(struct posix_acl *acl)
	60	{
	61	if (acl)
	62	atomic_inc(&acl->a_refcount);
	63	return acl;
	64	}
	65
	66	/*
	67	* Free an ACL handle.
	68	*/
	69	static inline void
	70	posix_acl_release(struct posix_acl *acl)
	71	{
	72	if (acl && atomic_dec_and_test(&acl->a_refcount))
3567866b	73	kfree_rcu(acl, a_rcu);
1da177e4 LT	74	}
	75
	76
	77	/* posix_acl.c */
	78
f61f6da0	79	extern void posix_acl_init(struct posix_acl *, int);
dd0fc66f	80	extern struct posix_acl *posix_acl_alloc(int, gfp_t);
1da177e4 LT	81	extern int posix_acl_valid(const struct posix_acl *);
1da177e4 LT	82	extern int posix_acl_permission(struct inode , const struct posix_acl , int);
3a5fba19	83	extern struct posix_acl *posix_acl_from_mode(umode_t, gfp_t);
d6952123	84	extern int posix_acl_equiv_mode(const struct posix_acl , umode_t );
d3fb6120	85	extern int posix_acl_create(struct posix_acl *, gfp_t, umode_t );
86bc704d	86	extern int posix_acl_chmod(struct posix_acl **, gfp_t, umode_t);
1da177e4 LT	87
	88	extern struct posix_acl get_posix_acl(struct inode , int);
	89	extern int set_posix_acl(struct inode , int, struct posix_acl );
	90
641cf4a6	91	#ifdef CONFIG_FS_POSIX_ACL
951c0d66	92	static inline struct posix_acl *acl_by_type(struct inode inode, int type)
073aaa1b	93	{
073aaa1b AV	94	switch (type) {
073aaa1b AV	95	case ACL_TYPE_ACCESS:
951c0d66	96	return &inode->i_acl;
073aaa1b	97	case ACL_TYPE_DEFAULT:
951c0d66	98	return &inode->i_default_acl;
073aaa1b	99	default:
951c0d66	100	BUG();
073aaa1b	101	}
951c0d66 AV	102	}
	103
	104	static inline struct posix_acl get_cached_acl(struct inode inode, int type)
	105	{
	106	struct posix_acl **p = acl_by_type(inode, type);
	107	struct posix_acl acl = ACCESS_ONCE(p);
073aaa1b AV	108	if (acl) {
	109	spin_lock(&inode->i_lock);
	110	acl = *p;
	111	if (acl != ACL_NOT_CACHED)
	112	acl = posix_acl_dup(acl);
	113	spin_unlock(&inode->i_lock);
	114	}
	115	return acl;
	116	}
	117
3567866b	118	static inline struct posix_acl get_cached_acl_rcu(struct inode inode, int type)
1e1743eb	119	{
3567866b	120	return rcu_dereference(*acl_by_type(inode, type));
1e1743eb NP	121	}
1e1743eb NP	122
073aaa1b AV	123	static inline void set_cached_acl(struct inode *inode,
	124	int type,
	125	struct posix_acl *acl)
	126	{
951c0d66 AV	127	struct posix_acl **p = acl_by_type(inode, type);
951c0d66 AV	128	struct posix_acl *old;
073aaa1b	129	spin_lock(&inode->i_lock);
951c0d66	130	old = *p;
3567866b	131	rcu_assign_pointer(*p, posix_acl_dup(acl));
073aaa1b AV	132	spin_unlock(&inode->i_lock);
	133	if (old != ACL_NOT_CACHED)
	134	posix_acl_release(old);
	135	}
	136
	137	static inline void forget_cached_acl(struct inode *inode, int type)
	138	{
951c0d66 AV	139	struct posix_acl **p = acl_by_type(inode, type);
951c0d66 AV	140	struct posix_acl *old;
073aaa1b	141	spin_lock(&inode->i_lock);
951c0d66 AV	142	old = *p;
951c0d66 AV	143	*p = ACL_NOT_CACHED;
073aaa1b AV	144	spin_unlock(&inode->i_lock);
	145	if (old != ACL_NOT_CACHED)
	146	posix_acl_release(old);
	147	}
796bd952 SW	148
	149	static inline void forget_all_cached_acls(struct inode *inode)
	150	{
	151	struct posix_acl old_access, old_default;
	152	spin_lock(&inode->i_lock);
	153	old_access = inode->i_acl;
	154	old_default = inode->i_default_acl;
	155	inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
	156	spin_unlock(&inode->i_lock);
	157	if (old_access != ACL_NOT_CACHED)
	158	posix_acl_release(old_access);
	159	if (old_default != ACL_NOT_CACHED)
	160	posix_acl_release(old_default);
	161	}
641cf4a6	162	#endif
72c04902 AV	163
	164	static inline void cache_no_acl(struct inode *inode)
	165	{
	166	#ifdef CONFIG_FS_POSIX_ACL
	167	inode->i_acl = NULL;
	168	inode->i_default_acl = NULL;
	169	#endif
	170	}
	171
1da177e4	172	#endif /* __LINUX_POSIX_ACL_H */