[linux-block.git] / include / linux / namei.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_NAMEI_H
#define _LINUX_NAMEI_H

#include <linux/fs.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};

/* pathwalk mode */
#define LOOKUP_FOLLOW		0x0001	/* follow links at the end */
#define LOOKUP_DIRECTORY	0x0002	/* require a directory */
#define LOOKUP_AUTOMOUNT	0x0004  /* force terminal automount */
#define LOOKUP_EMPTY		0x4000	/* accept empty path [user_... only] */
#define LOOKUP_DOWN		0x8000	/* follow mounts in the starting point */
#define LOOKUP_MOUNTPOINT	0x0080	/* follow mounts in the end */

#define LOOKUP_REVAL		0x0020	/* tell ->d_revalidate() to trust no cache */
#define LOOKUP_RCU		0x0040	/* RCU pathwalk mode; semi-internal */

/* These tell filesystem methods that we are dealing with the final component... */
#define LOOKUP_OPEN		0x0100	/* ... in open */
#define LOOKUP_CREATE		0x0200	/* ... in object creation */
#define LOOKUP_EXCL		0x0400	/* ... in exclusive creation */
#define LOOKUP_RENAME_TARGET	0x0800	/* ... in destination of rename() */

/* internal use only */
#define LOOKUP_PARENT		0x0010

/* Scoping flags for lookup. */
#define LOOKUP_NO_SYMLINKS	0x010000 /* No symlink crossing. */
#define LOOKUP_NO_MAGICLINKS	0x020000 /* No nd_jump_link() crossing. */
#define LOOKUP_NO_XDEV		0x040000 /* No mountpoint crossing. */
#define LOOKUP_BENEATH		0x080000 /* No escaping from starting point. */
#define LOOKUP_IN_ROOT		0x100000 /* Treat dirfd as fs root. */
#define LOOKUP_CACHED		0x200000 /* Only do cached lookup */
/* LOOKUP_* flags which do scope-related checks based on the dirfd. */
#define LOOKUP_IS_SCOPED (LOOKUP_BENEATH | LOOKUP_IN_ROOT)

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);
}

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 struct dentry *try_lookup_one_len(const char *, struct dentry *, int);
extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
extern struct dentry *lookup_one_len_unlocked(const char *, struct dentry *, int);
extern struct dentry *lookup_positive_unlocked(const char *, struct dentry *, int);
struct dentry *lookup_one(struct user_namespace *, const char *, struct dentry *, int);
struct dentry *lookup_one_unlocked(struct user_namespace *mnt_userns,
				   const char *name, struct dentry *base,
				   int len);
struct dentry *lookup_one_positive_unlocked(struct user_namespace *mnt_userns,
					    const char *name,
					    struct dentry *base, int len);

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 int __must_check nd_jump_link(const 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
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
1da177e4 LT	2	#ifndef _LINUX_NAMEI_H
	3	#define _LINUX_NAMEI_H
	4
adb21d2b	5	#include <linux/fs.h>
b853a161	6	#include <linux/kernel.h>
c5e725f3	7	#include <linux/path.h>
b853a161 AV	8	#include <linux/fcntl.h>
b853a161 AV	9	#include <linux/errno.h>
1da177e4	10
737bebd1	11	enum { MAX_NESTED_LINKS = 8 };
1da177e4	12
894bc8c4 AV	13	#define MAXSYMLINKS 40
894bc8c4 AV	14
1da177e4 LT	15	/*
	16	* Type of the last component on LOOKUP_PARENT
	17	*/
b4c03536	18	enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT};
1da177e4	19
6b61aed0 AV	20	/* pathwalk mode */
	21	#define LOOKUP_FOLLOW 0x0001 /* follow links at the end */
	22	#define LOOKUP_DIRECTORY 0x0002 /* require a directory */
	23	#define LOOKUP_AUTOMOUNT 0x0004 /* force terminal automount */
	24	#define LOOKUP_EMPTY 0x4000 /* accept empty path [user_... only] */
	25	#define LOOKUP_DOWN 0x8000 /* follow mounts in the starting point */
161aff1d	26	#define LOOKUP_MOUNTPOINT 0x0080 /* follow mounts in the end */
6b61aed0 AV	27
	28	#define LOOKUP_REVAL 0x0020 /* tell ->d_revalidate() to trust no cache */
	29	#define LOOKUP_RCU 0x0040 /* RCU pathwalk mode; semi-internal */
	30
	31	/* These tell filesystem methods that we are dealing with the final component... */
	32	#define LOOKUP_OPEN 0x0100 /* ... in open */
	33	#define LOOKUP_CREATE 0x0200 /* ... in object creation */
	34	#define LOOKUP_EXCL 0x0400 /* ... in exclusive creation */
	35	#define LOOKUP_RENAME_TARGET 0x0800 /* ... in destination of rename() */
	36
	37	/* internal use only */
31e6b01f	38	#define LOOKUP_PARENT 0x0010
16c2cd71	39
27812141 AS	40	/* Scoping flags for lookup. */
27812141 AS	41	#define LOOKUP_NO_SYMLINKS 0x010000 /* No symlink crossing. */
4b99d499	42	#define LOOKUP_NO_MAGICLINKS 0x020000 /* No nd_jump_link() crossing. */
72ba2929	43	#define LOOKUP_NO_XDEV 0x040000 /* No mountpoint crossing. */
adb21d2b	44	#define LOOKUP_BENEATH 0x080000 /* No escaping from starting point. */
8db52c7e	45	#define LOOKUP_IN_ROOT 0x100000 /* Treat dirfd as fs root. */
6c6ec2b0	46	#define LOOKUP_CACHED 0x200000 /* Only do cached lookup */
adb21d2b	47	/* LOOKUP_* flags which do scope-related checks based on the dirfd. */
8db52c7e	48	#define LOOKUP_IS_SCOPED (LOOKUP_BENEATH \| LOOKUP_IN_ROOT)
27812141	49
eedf265a EB	50	extern int path_pts(struct path *path);
eedf265a EB	51
1fa1e7f6	52	extern int user_path_at_empty(int, const char __user , unsigned, struct path , int *empty);
2d8f3038	53
b853a161 AV	54	static inline int user_path_at(int dfd, const char __user *name, unsigned flags,
	55	struct path *path)
	56	{
	57	return user_path_at_empty(dfd, name, flags, path, NULL);
	58	}
	59
d1811465 AV	60	extern int kern_path(const char , unsigned, struct path );
d1811465 AV	61
1ac12b4b JL	62	extern struct dentry kern_path_create(int, const char , struct path *, unsigned int);
1ac12b4b JL	63	extern struct dentry user_path_create(int, const char __user , struct path *, unsigned int);
921a1650	64	extern void done_path_create(struct path , struct dentry );
79714f72	65	extern struct dentry kern_path_locked(const char , struct path *);
1da177e4	66
0da0b7fd	67	extern struct dentry try_lookup_one_len(const char , struct dentry *, int);
eead1911	68	extern struct dentry lookup_one_len(const char , struct dentry *, int);
bbddca8e	69	extern struct dentry lookup_one_len_unlocked(const char , struct dentry *, int);
6c2d4798	70	extern struct dentry lookup_positive_unlocked(const char , struct dentry *, int);
c2fd68b6	71	struct dentry lookup_one(struct user_namespace , const char , struct dentry , int);
00675017 CB	72	struct dentry lookup_one_unlocked(struct user_namespace mnt_userns,
	73	const char name, struct dentry base,
	74	int len);
	75	struct dentry lookup_one_positive_unlocked(struct user_namespace mnt_userns,
	76	const char *name,
	77	struct dentry *base, int len);
1da177e4	78
cc53ce53	79	extern int follow_down_one(struct path *);
7cc90cc3	80	extern int follow_down(struct path *);
bab77ebf	81	extern int follow_up(struct path *);
1da177e4 LT	82
	83	extern struct dentry lock_rename(struct dentry , struct dentry *);
	84	extern void unlock_rename(struct dentry , struct dentry );
	85
ea4af4aa	86	extern int __must_check nd_jump_link(const struct path *path);
1da177e4	87
03514685 DG	88	static inline void nd_terminate_link(void *name, size_t len, size_t maxlen)
	89	{
	90	((char *) name)[min(len, maxlen)] = '\0';
	91	}
	92
b9d6ba94 JL	93	/**
	94	* retry_estale - determine whether the caller should retry an operation
	95	* @error: the error that would currently be returned
	96	* @flags: flags being used for next lookup attempt
	97	*
	98	* Check to see if the error code was -ESTALE, and then determine whether
	99	* to retry the call based on whether "flags" already has LOOKUP_REVAL set.
	100	*
	101	* Returns true if the caller should try the operation again.
	102	*/
	103	static inline bool
	104	retry_estale(const long error, const unsigned int flags)
	105	{
	106	return error == -ESTALE && !(flags & LOOKUP_REVAL);
	107	}
	108
1da177e4	109	#endif /* _LINUX_NAMEI_H */