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

#ifndef _LINUX_NAMEI_H
#define _LINUX_NAMEI_H

#include <linux/dcache.h>
#include <linux/errno.h>
#include <linux/linkage.h>
#include <linux/path.h>

struct vfsmount;
struct nameidata;

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

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

#define user_path(name, path) user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW, path)
#define user_lpath(name, path) user_path_at(AT_FDCWD, name, 0, path)
#define user_path_dir(name, path) \
	user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, path)

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 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 nameidata *nd, 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
82b0547c	4	#include <linux/dcache.h>
08b60f84	5	#include <linux/errno.h>
1da177e4	6	#include <linux/linkage.h>
c5e725f3	7	#include <linux/path.h>
1da177e4 LT	8
1da177e4 LT	9	struct vfsmount;
1f55a6ec	10	struct nameidata;
1da177e4	11
737bebd1	12	enum { MAX_NESTED_LINKS = 8 };
1da177e4	13
894bc8c4 AV	14	#define MAXSYMLINKS 40
894bc8c4 AV	15
1da177e4 LT	16	/*
	17	* Type of the last component on LOOKUP_PARENT
	18	*/
	19	enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
	20
	21	/*
	22	* The bitmask for a lookup event:
	23	* - follow links at the end
	24	* - require a directory
	25	* - ending slashes ok even for nonexistent files
47a0dfaa	26	* - internal "there are more path components" flag
1da177e4	27	* - dentry cache is untrusted; force a real lookup
6f45b656	28	* - suppress terminal automount
1da177e4	29	*/
31e6b01f NP	30	#define LOOKUP_FOLLOW 0x0001
31e6b01f NP	31	#define LOOKUP_DIRECTORY 0x0002
d94c177b	32	#define LOOKUP_AUTOMOUNT 0x0004
31e6b01f NP	33
	34	#define LOOKUP_PARENT 0x0010
	35	#define LOOKUP_REVAL 0x0020
	36	#define LOOKUP_RCU 0x0040
b6c8069d	37
1da177e4 LT	38	/*
	39	* Intent data
	40	*/
3516586a AV	41	#define LOOKUP_OPEN 0x0100
	42	#define LOOKUP_CREATE 0x0200
	43	#define LOOKUP_EXCL 0x0400
4e9ed2f8	44	#define LOOKUP_RENAME_TARGET 0x0800
1da177e4	45
16c2cd71	46	#define LOOKUP_JUMPED 0x1000
5b6ca027	47	#define LOOKUP_ROOT 0x2000
f52e0c11	48	#define LOOKUP_EMPTY 0x4000
16c2cd71	49
2d8f3038	50	extern int user_path_at(int, const char __user , unsigned, struct path );
1fa1e7f6	51	extern int user_path_at_empty(int, const char __user , unsigned, struct path , int *empty);
2d8f3038 AV	52
	53	#define user_path(name, path) user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW, path)
	54	#define user_lpath(name, path) user_path_at(AT_FDCWD, name, 0, path)
	55	#define user_path_dir(name, path) \
	56	user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW \| LOOKUP_DIRECTORY, path)
	57
d1811465 AV	58	extern int kern_path(const char , unsigned, struct path );
d1811465 AV	59
1ac12b4b JL	60	extern struct dentry kern_path_create(int, const char , struct path *, unsigned int);
1ac12b4b JL	61	extern struct dentry user_path_create(int, const char __user , struct path *, unsigned int);
921a1650	62	extern void done_path_create(struct path , struct dentry );
79714f72	63	extern struct dentry kern_path_locked(const char , struct path *);
2d864651	64	extern int kern_path_mountpoint(int, const char , struct path , unsigned int);
1da177e4	65
eead1911	66	extern struct dentry lookup_one_len(const char , struct dentry *, int);
1da177e4	67
cc53ce53	68	extern int follow_down_one(struct path *);
7cc90cc3	69	extern int follow_down(struct path *);
bab77ebf	70	extern int follow_up(struct path *);
1da177e4 LT	71
	72	extern struct dentry lock_rename(struct dentry , struct dentry *);
	73	extern void unlock_rename(struct dentry , struct dentry );
	74
b5fb63c1	75	extern void nd_jump_link(struct nameidata nd, struct path path);
1da177e4	76
03514685 DG	77	static inline void nd_terminate_link(void *name, size_t len, size_t maxlen)
	78	{
	79	((char *) name)[min(len, maxlen)] = '\0';
	80	}
	81
b9d6ba94 JL	82	/**
	83	* retry_estale - determine whether the caller should retry an operation
	84	* @error: the error that would currently be returned
	85	* @flags: flags being used for next lookup attempt
	86	*
	87	* Check to see if the error code was -ESTALE, and then determine whether
	88	* to retry the call based on whether "flags" already has LOOKUP_REVAL set.
	89	*
	90	* Returns true if the caller should try the operation again.
	91	*/
	92	static inline bool
	93	retry_estale(const long error, const unsigned int flags)
	94	{
	95	return error == -ESTALE && !(flags & LOOKUP_REVAL);
	96	}
	97
1da177e4	98	#endif /* _LINUX_NAMEI_H */