1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Copyright (c) 2000,2002-2003,2005 Silicon Graphics, Inc.
  4 * All Rights Reserved.
  5 */
  6#ifndef __XFS_ATTR_H__
  7#define	__XFS_ATTR_H__
  8
  9struct xfs_inode;
 10struct xfs_da_args;
 11struct xfs_attr_list_context;
 12
 13/*
 14 * Large attribute lists are structured around Btrees where all the data
 15 * elements are in the leaf nodes.  Attribute names are hashed into an int,
 16 * then that int is used as the index into the Btree.  Since the hashval
 17 * of an attribute name may not be unique, we may have duplicate keys.
 18 * The internal links in the Btree are logical block offsets into the file.
 19 *
 20 * Small attribute lists use a different format and are packed as tightly
 21 * as possible so as to fit into the literal area of the inode.
 22 */
 23
 24/*========================================================================
 25 * External interfaces
 26 *========================================================================*/
 27
 28
 29#define ATTR_DONTFOLLOW	0x0001	/* -- unused, from IRIX -- */
 30#define ATTR_ROOT	0x0002	/* use attrs in root (trusted) namespace */
 31#define ATTR_TRUST	0x0004	/* -- unused, from IRIX -- */
 32#define ATTR_SECURE	0x0008	/* use attrs in security namespace */
 33#define ATTR_CREATE	0x0010	/* pure create: fail if attr already exists */
 34#define ATTR_REPLACE	0x0020	/* pure set: fail if attr does not exist */
 35
 36#define ATTR_KERNOTIME	0x1000	/* [kernel] don't update inode timestamps */
 37#define ATTR_KERNOVAL	0x2000	/* [kernel] get attr size only, not value */
 38
 39#define ATTR_INCOMPLETE	0x4000	/* [kernel] return INCOMPLETE attr keys */
 40#define ATTR_ALLOC	0x8000	/* allocate xattr buffer on demand */
 41
 42#define XFS_ATTR_FLAGS \
 43	{ ATTR_DONTFOLLOW, 	"DONTFOLLOW" }, \
 44	{ ATTR_ROOT,		"ROOT" }, \
 45	{ ATTR_TRUST,		"TRUST" }, \
 46	{ ATTR_SECURE,		"SECURE" }, \
 47	{ ATTR_CREATE,		"CREATE" }, \
 48	{ ATTR_REPLACE,		"REPLACE" }, \
 49	{ ATTR_KERNOTIME,	"KERNOTIME" }, \
 50	{ ATTR_KERNOVAL,	"KERNOVAL" }, \
 51	{ ATTR_INCOMPLETE,	"INCOMPLETE" }, \
 52	{ ATTR_ALLOC,		"ALLOC" }
 53
 54/*
 55 * The maximum size (into the kernel or returned from the kernel) of an
 56 * attribute value or the buffer used for an attr_list() call.  Larger
 57 * sizes will result in an ERANGE return code.
 58 */
 59#define	ATTR_MAX_VALUELEN	(64*1024)	/* max length of a value */
 60
 61/*
 62 * Define how lists of attribute names are returned to the user from
 63 * the attr_list() call.  A large, 32bit aligned, buffer is passed in
 64 * along with its size.  We put an array of offsets at the top that each
 65 * reference an attrlist_ent_t and pack the attrlist_ent_t's at the bottom.
 66 */
 67typedef struct attrlist {
 68	__s32	al_count;	/* number of entries in attrlist */
 69	__s32	al_more;	/* T/F: more attrs (do call again) */
 70	__s32	al_offset[1];	/* byte offsets of attrs [var-sized] */
 71} attrlist_t;
 72
 73/*
 74 * Show the interesting info about one attribute.  This is what the
 75 * al_offset[i] entry points to.
 76 */
 77typedef struct attrlist_ent {	/* data from attr_list() */
 78	__u32	a_valuelen;	/* number bytes in value of attr */
 79	char	a_name[1];	/* attr name (NULL terminated) */
 80} attrlist_ent_t;
 81
 82/*
 83 * Given a pointer to the (char*) buffer containing the attr_list() result,
 84 * and an index, return a pointer to the indicated attribute in the buffer.
 85 */
 86#define	ATTR_ENTRY(buffer, index)		\
 87	((attrlist_ent_t *)			\
 88	 &((char *)buffer)[ ((attrlist_t *)(buffer))->al_offset[index] ])
 89
 90/*
 91 * Kernel-internal version of the attrlist cursor.
 92 */
 93typedef struct attrlist_cursor_kern {
 94	__u32	hashval;	/* hash value of next entry to add */
 95	__u32	blkno;		/* block containing entry (suggestion) */
 96	__u32	offset;		/* offset in list of equal-hashvals */
 97	__u16	pad1;		/* padding to match user-level */
 98	__u8	pad2;		/* padding to match user-level */
 99	__u8	initted;	/* T/F: cursor has been initialized */
100} attrlist_cursor_kern_t;
101
102
103/*========================================================================
104 * Structure used to pass context around among the routines.
105 *========================================================================*/
106
107
108/* void; state communicated via *context */
109typedef void (*put_listent_func_t)(struct xfs_attr_list_context *, int,
110			      unsigned char *, int, int);
111
112typedef struct xfs_attr_list_context {
113	struct xfs_trans		*tp;
114	struct xfs_inode		*dp;		/* inode */
115	struct attrlist_cursor_kern	*cursor;	/* position in list */
116	char				*alist;		/* output buffer */
117
118	/*
119	 * Abort attribute list iteration if non-zero.  Can be used to pass
120	 * error values to the xfs_attr_list caller.
121	 */
122	int				seen_enough;
123
124	ssize_t				count;		/* num used entries */
125	int				dupcnt;		/* count dup hashvals seen */
126	int				bufsize;	/* total buffer size */
127	int				firstu;		/* first used byte in buffer */
128	int				flags;		/* from VOP call */
129	int				resynch;	/* T/F: resynch with cursor */
130	put_listent_func_t		put_listent;	/* list output fmt function */
131	int				index;		/* index into output buffer */
132} xfs_attr_list_context_t;
133
134
135/*========================================================================
136 * Function prototypes for the kernel.
137 *========================================================================*/
138
139/*
140 * Overall external interface routines.
141 */
142int xfs_attr_inactive(struct xfs_inode *dp);
143int xfs_attr_list_int_ilocked(struct xfs_attr_list_context *);
144int xfs_attr_list_int(struct xfs_attr_list_context *);
145int xfs_inode_hasattr(struct xfs_inode *ip);
146int xfs_attr_get_ilocked(struct xfs_inode *ip, struct xfs_da_args *args);
147int xfs_attr_get(struct xfs_inode *ip, const unsigned char *name,
148		 unsigned char **value, int *valuelenp, int flags);
149int xfs_attr_set(struct xfs_inode *dp, const unsigned char *name,
150		 unsigned char *value, int valuelen, int flags);
151int xfs_attr_set_args(struct xfs_da_args *args);
152int xfs_attr_remove(struct xfs_inode *dp, const unsigned char *name, int flags);
153int xfs_attr_remove_args(struct xfs_da_args *args);
154int xfs_attr_list(struct xfs_inode *dp, char *buffer, int bufsize,
155		  int flags, struct attrlist_cursor_kern *cursor);
156bool xfs_attr_namecheck(const void *name, size_t length);
157
158#endif	/* __XFS_ATTR_H__ */