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 
9 struct xfs_inode;
10 struct xfs_da_args;
11 struct 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 
41 #define XFS_ATTR_FLAGS \
42 	{ ATTR_DONTFOLLOW, 	"DONTFOLLOW" }, \
43 	{ ATTR_ROOT,		"ROOT" }, \
44 	{ ATTR_TRUST,		"TRUST" }, \
45 	{ ATTR_SECURE,		"SECURE" }, \
46 	{ ATTR_CREATE,		"CREATE" }, \
47 	{ ATTR_REPLACE,		"REPLACE" }, \
48 	{ ATTR_KERNOTIME,	"KERNOTIME" }, \
49 	{ ATTR_KERNOVAL,	"KERNOVAL" }, \
50 	{ ATTR_INCOMPLETE,	"INCOMPLETE" }
51 
52 /*
53  * The maximum size (into the kernel or returned from the kernel) of an
54  * attribute value or the buffer used for an attr_list() call.  Larger
55  * sizes will result in an ERANGE return code.
56  */
57 #define	ATTR_MAX_VALUELEN	(64*1024)	/* max length of a value */
58 
59 /*
60  * Define how lists of attribute names are returned to the user from
61  * the attr_list() call.  A large, 32bit aligned, buffer is passed in
62  * along with its size.  We put an array of offsets at the top that each
63  * reference an attrlist_ent_t and pack the attrlist_ent_t's at the bottom.
64  */
65 typedef struct attrlist {
66 	__s32	al_count;	/* number of entries in attrlist */
67 	__s32	al_more;	/* T/F: more attrs (do call again) */
68 	__s32	al_offset[1];	/* byte offsets of attrs [var-sized] */
69 } attrlist_t;
70 
71 /*
72  * Show the interesting info about one attribute.  This is what the
73  * al_offset[i] entry points to.
74  */
75 typedef struct attrlist_ent {	/* data from attr_list() */
76 	__u32	a_valuelen;	/* number bytes in value of attr */
77 	char	a_name[1];	/* attr name (NULL terminated) */
78 } attrlist_ent_t;
79 
80 /*
81  * Given a pointer to the (char*) buffer containing the attr_list() result,
82  * and an index, return a pointer to the indicated attribute in the buffer.
83  */
84 #define	ATTR_ENTRY(buffer, index)		\
85 	((attrlist_ent_t *)			\
86 	 &((char *)buffer)[ ((attrlist_t *)(buffer))->al_offset[index] ])
87 
88 /*
89  * Kernel-internal version of the attrlist cursor.
90  */
91 typedef struct attrlist_cursor_kern {
92 	__u32	hashval;	/* hash value of next entry to add */
93 	__u32	blkno;		/* block containing entry (suggestion) */
94 	__u32	offset;		/* offset in list of equal-hashvals */
95 	__u16	pad1;		/* padding to match user-level */
96 	__u8	pad2;		/* padding to match user-level */
97 	__u8	initted;	/* T/F: cursor has been initialized */
98 } attrlist_cursor_kern_t;
99 
100 
101 /*========================================================================
102  * Structure used to pass context around among the routines.
103  *========================================================================*/
104 
105 
106 /* void; state communicated via *context */
107 typedef void (*put_listent_func_t)(struct xfs_attr_list_context *, int,
108 			      unsigned char *, int, int);
109 
110 typedef struct xfs_attr_list_context {
111 	struct xfs_trans		*tp;
112 	struct xfs_inode		*dp;		/* inode */
113 	struct attrlist_cursor_kern	*cursor;	/* position in list */
114 	char				*alist;		/* output buffer */
115 	int				seen_enough;	/* T/F: seen enough of list? */
116 	ssize_t				count;		/* num used entries */
117 	int				dupcnt;		/* count dup hashvals seen */
118 	int				bufsize;	/* total buffer size */
119 	int				firstu;		/* first used byte in buffer */
120 	int				flags;		/* from VOP call */
121 	int				resynch;	/* T/F: resynch with cursor */
122 	put_listent_func_t		put_listent;	/* list output fmt function */
123 	int				index;		/* index into output buffer */
124 } xfs_attr_list_context_t;
125 
126 
127 /*========================================================================
128  * Function prototypes for the kernel.
129  *========================================================================*/
130 
131 /*
132  * Overall external interface routines.
133  */
134 int xfs_attr_inactive(struct xfs_inode *dp);
135 int xfs_attr_list_int_ilocked(struct xfs_attr_list_context *);
136 int xfs_attr_list_int(struct xfs_attr_list_context *);
137 int xfs_inode_hasattr(struct xfs_inode *ip);
138 int xfs_attr_get_ilocked(struct xfs_inode *ip, struct xfs_da_args *args);
139 int xfs_attr_get(struct xfs_inode *ip, const unsigned char *name,
140 		 unsigned char *value, int *valuelenp, int flags);
141 int xfs_attr_set(struct xfs_inode *dp, const unsigned char *name,
142 		 unsigned char *value, int valuelen, int flags);
143 int xfs_attr_set_args(struct xfs_da_args *args);
144 int xfs_attr_remove(struct xfs_inode *dp, const unsigned char *name, int flags);
145 int xfs_attr_remove_args(struct xfs_da_args *args);
146 int xfs_attr_list(struct xfs_inode *dp, char *buffer, int bufsize,
147 		  int flags, struct attrlist_cursor_kern *cursor);
148 
149 
150 #endif	/* __XFS_ATTR_H__ */
151