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

#ifndef _LINUX_NAMEI_H
#define _LINUX_NAMEI_H

#include <linux/kernel.h>
#include <linux/path.h>
#include <linux/fcntl.h>
#include <linux/errno.h>

enum { MAX_NESTED_LINKS = 8 };

#define MAXSYMLINKS 40

/*
 * Type of the last component on LOOKUP_PARENT
 */
enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};

/*
 * The bitmask for a lookup event:
 *  - follow links at the end
 *  - require a directory
 *  - ending slashes ok even for nonexistent files
 *  - internal "there are more path components" flag
 *  - dentry cache is untrusted; force a real lookup
 *  - suppress terminal automount
 */
#define LOOKUP_FOLLOW		0x0001
#define LOOKUP_DIRECTORY	0x0002
#define LOOKUP_AUTOMOUNT	0x0004

#define LOOKUP_PARENT		0x0010
#define LOOKUP_REVAL		0x0020
#define LOOKUP_RCU		0x0040
#define LOOKUP_NO_REVAL		0x0080

/*
 * Intent data
 */
#define LOOKUP_OPEN		0x0100
#define LOOKUP_CREATE		0x0200
#define LOOKUP_EXCL		0x0400
#define LOOKUP_RENAME_TARGET	0x0800

#define LOOKUP_JUMPED		0x1000
#define LOOKUP_ROOT		0x2000
#define LOOKUP_EMPTY		0x4000

extern int path_pts(struct path *path);

extern int user_path_at_empty(int, const char __user *, unsigned, struct path *, int *empty);

static inline int user_path_at(int dfd, const char __user *name, unsigned flags,
		 struct path *path)
{
	return user_path_at_empty(dfd, name, flags, path, NULL);
}

static inline int user_path(const char __user *name, struct path *path)
{
	return user_path_at_empty(AT_FDCWD, name, LOOKUP_FOLLOW, path, NULL);
}

static inline int user_lpath(const char __user *name, struct path *path)
{
	return user_path_at_empty(AT_FDCWD, name, 0, path, NULL);
}

static inline int user_path_dir(const char __user *name, struct path *path)
{
	return user_path_at_empty(AT_FDCWD, name,
				  LOOKUP_FOLLOW | LOOKUP_DIRECTORY, path, NULL);
}

extern int kern_path(const char *, unsigned, struct path *);

extern struct dentry *kern_path_create(int, const char *, struct path *, unsigned int);
extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int);
extern void done_path_create(struct path *, struct dentry *);
extern struct dentry *kern_path_locked(const char *, struct path *);
extern int kern_path_mountpoint(int, const char *, struct path *, unsigned int);

extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
extern struct dentry *lookup_one_len_unlocked(const char *, struct dentry *, int);
struct qstr;
extern struct dentry *lookup_hash(const struct qstr *, struct dentry *);

extern int follow_down_one(struct path *);
extern int follow_down(struct path *);
extern int follow_up(struct path *);

extern struct dentry *lock_rename(struct dentry *, struct dentry *);
extern void unlock_rename(struct dentry *, struct dentry *);

extern void nd_jump_link(struct path *path);

static inline void nd_terminate_link(void *name, size_t len, size_t maxlen)
{
	((char *) name)[min(len, maxlen)] = '\0';
}

/**
 * retry_estale - determine whether the caller should retry an operation
 * @error: the error that would currently be returned
 * @flags: flags being used for next lookup attempt
 *
 * Check to see if the error code was -ESTALE, and then determine whether
 * to retry the call based on whether "flags" already has LOOKUP_REVAL set.
 *
 * Returns true if the caller should try the operation again.
 */
static inline bool
retry_estale(const long error, const unsigned int flags)
{
	return error == -ESTALE && !(flags & LOOKUP_REVAL);
}

#endif /* _LINUX_NAMEI_H */
Commit	Line	Data
1da177e4 LT	1	#ifndef _LINUX_NAMEI_H
	2	#define _LINUX_NAMEI_H
	3
b853a161	4	#include <linux/kernel.h>
c5e725f3	5	#include <linux/path.h>
b853a161 AV	6	#include <linux/fcntl.h>
b853a161 AV	7	#include <linux/errno.h>
1da177e4	8
737bebd1	9	enum { MAX_NESTED_LINKS = 8 };
1da177e4	10
894bc8c4 AV	11	#define MAXSYMLINKS 40
894bc8c4 AV	12
1da177e4 LT	13	/*
	14	* Type of the last component on LOOKUP_PARENT
	15	*/
	16	enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
	17
	18	/*
	19	* The bitmask for a lookup event:
	20	* - follow links at the end
	21	* - require a directory
	22	* - ending slashes ok even for nonexistent files
47a0dfaa	23	* - internal "there are more path components" flag
1da177e4	24	* - dentry cache is untrusted; force a real lookup
6f45b656	25	* - suppress terminal automount
1da177e4	26	*/
31e6b01f NP	27	#define LOOKUP_FOLLOW 0x0001
31e6b01f NP	28	#define LOOKUP_DIRECTORY 0x0002
d94c177b	29	#define LOOKUP_AUTOMOUNT 0x0004
31e6b01f NP	30
	31	#define LOOKUP_PARENT 0x0010
	32	#define LOOKUP_REVAL 0x0020
	33	#define LOOKUP_RCU 0x0040
949a852e	34	#define LOOKUP_NO_REVAL 0x0080
b6c8069d	35
1da177e4 LT	36	/*
	37	* Intent data
	38	*/
3516586a AV	39	#define LOOKUP_OPEN 0x0100
	40	#define LOOKUP_CREATE 0x0200
	41	#define LOOKUP_EXCL 0x0400
4e9ed2f8	42	#define LOOKUP_RENAME_TARGET 0x0800
1da177e4	43
16c2cd71	44	#define LOOKUP_JUMPED 0x1000
5b6ca027	45	#define LOOKUP_ROOT 0x2000
f52e0c11	46	#define LOOKUP_EMPTY 0x4000
16c2cd71	47
eedf265a EB	48	extern int path_pts(struct path *path);
eedf265a EB	49
1fa1e7f6	50	extern int user_path_at_empty(int, const char __user , unsigned, struct path , int *empty);
2d8f3038	51
b853a161 AV	52	static inline int user_path_at(int dfd, const char __user *name, unsigned flags,
	53	struct path *path)
	54	{
	55	return user_path_at_empty(dfd, name, flags, path, NULL);
	56	}
	57
	58	static inline int user_path(const char __user name, struct path path)
	59	{
	60	return user_path_at_empty(AT_FDCWD, name, LOOKUP_FOLLOW, path, NULL);
	61	}
	62
	63	static inline int user_lpath(const char __user name, struct path path)
	64	{
	65	return user_path_at_empty(AT_FDCWD, name, 0, path, NULL);
	66	}
	67
	68	static inline int user_path_dir(const char __user name, struct path path)
	69	{
	70	return user_path_at_empty(AT_FDCWD, name,
	71	LOOKUP_FOLLOW \| LOOKUP_DIRECTORY, path, NULL);
	72	}
2d8f3038	73
d1811465 AV	74	extern int kern_path(const char , unsigned, struct path );
d1811465 AV	75
1ac12b4b JL	76	extern struct dentry kern_path_create(int, const char , struct path *, unsigned int);
1ac12b4b JL	77	extern struct dentry user_path_create(int, const char __user , struct path *, unsigned int);
921a1650	78	extern void done_path_create(struct path , struct dentry );
79714f72	79	extern struct dentry kern_path_locked(const char , struct path *);
2d864651	80	extern int kern_path_mountpoint(int, const char , struct path , unsigned int);
1da177e4	81
eead1911	82	extern struct dentry lookup_one_len(const char , struct dentry *, int);
bbddca8e	83	extern struct dentry lookup_one_len_unlocked(const char , struct dentry *, int);
3c9fe8cd MS	84	struct qstr;
3c9fe8cd MS	85	extern struct dentry lookup_hash(const struct qstr , struct dentry *);
1da177e4	86
cc53ce53	87	extern int follow_down_one(struct path *);
7cc90cc3	88	extern int follow_down(struct path *);
bab77ebf	89	extern int follow_up(struct path *);
1da177e4 LT	90
	91	extern struct dentry lock_rename(struct dentry , struct dentry *);
	92	extern void unlock_rename(struct dentry , struct dentry );
	93
6e77137b	94	extern void nd_jump_link(struct path *path);
1da177e4	95
03514685 DG	96	static inline void nd_terminate_link(void *name, size_t len, size_t maxlen)
	97	{
	98	((char *) name)[min(len, maxlen)] = '\0';
	99	}
	100
b9d6ba94 JL	101	/**
	102	* retry_estale - determine whether the caller should retry an operation
	103	* @error: the error that would currently be returned
	104	* @flags: flags being used for next lookup attempt
	105	*
	106	* Check to see if the error code was -ESTALE, and then determine whether
	107	* to retry the call based on whether "flags" already has LOOKUP_REVAL set.
	108	*
	109	* Returns true if the caller should try the operation again.
	110	*/
	111	static inline bool
	112	retry_estale(const long error, const unsigned int flags)
	113	{
	114	return error == -ESTALE && !(flags & LOOKUP_REVAL);
	115	}
	116
1da177e4	117	#endif /* _LINUX_NAMEI_H */