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 /* -- ignored, 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 /* [kernel] allocate xattr buffer on demand */
41
42 #define ATTR_KERNEL_FLAGS \
43 (ATTR_KERNOTIME | ATTR_KERNOVAL | ATTR_INCOMPLETE | ATTR_ALLOC)
44
45 #define XFS_ATTR_FLAGS \
46 { ATTR_DONTFOLLOW, "DONTFOLLOW" }, \
47 { ATTR_ROOT, "ROOT" }, \
48 { ATTR_TRUST, "TRUST" }, \
49 { ATTR_SECURE, "SECURE" }, \
50 { ATTR_CREATE, "CREATE" }, \
51 { ATTR_REPLACE, "REPLACE" }, \
52 { ATTR_KERNOTIME, "KERNOTIME" }, \
53 { ATTR_KERNOVAL, "KERNOVAL" }, \
54 { ATTR_INCOMPLETE, "INCOMPLETE" }, \
55 { ATTR_ALLOC, "ALLOC" }
56
57 /*
58 * The maximum size (into the kernel or returned from the kernel) of an
59 * attribute value or the buffer used for an attr_list() call. Larger
60 * sizes will result in an ERANGE return code.
61 */
62 #define ATTR_MAX_VALUELEN (64*1024) /* max length of a value */
63
64 /*
65 * Define how lists of attribute names are returned to the user from
66 * the attr_list() call. A large, 32bit aligned, buffer is passed in
67 * along with its size. We put an array of offsets at the top that each
68 * reference an attrlist_ent_t and pack the attrlist_ent_t's at the bottom.
69 */
70 typedef struct attrlist {
71 __s32 al_count; /* number of entries in attrlist */
72 __s32 al_more; /* T/F: more attrs (do call again) */
73 __s32 al_offset[1]; /* byte offsets of attrs [var-sized] */
74 } attrlist_t;
75
76 /*
77 * Show the interesting info about one attribute. This is what the
78 * al_offset[i] entry points to.
79 */
80 typedef struct attrlist_ent { /* data from attr_list() */
81 __u32 a_valuelen; /* number bytes in value of attr */
82 char a_name[1]; /* attr name (NULL terminated) */
83 } attrlist_ent_t;
84
85 /*
86 * Given a pointer to the (char*) buffer containing the attr_list() result,
87 * and an index, return a pointer to the indicated attribute in the buffer.
88 */
89 #define ATTR_ENTRY(buffer, index) \
90 ((attrlist_ent_t *) \
91 &((char *)buffer)[ ((attrlist_t *)(buffer))->al_offset[index] ])
92
93 /*
94 * Kernel-internal version of the attrlist cursor.
95 */
96 typedef struct attrlist_cursor_kern {
97 __u32 hashval; /* hash value of next entry to add */
98 __u32 blkno; /* block containing entry (suggestion) */
99 __u32 offset; /* offset in list of equal-hashvals */
100 __u16 pad1; /* padding to match user-level */
101 __u8 pad2; /* padding to match user-level */
102 __u8 initted; /* T/F: cursor has been initialized */
103 } attrlist_cursor_kern_t;
104
105
106 /*========================================================================
107 * Structure used to pass context around among the routines.
108 *========================================================================*/
109
110
111 /* void; state communicated via *context */
112 typedef void (*put_listent_func_t)(struct xfs_attr_list_context *, int,
113 unsigned char *, int, int);
114
115 typedef struct xfs_attr_list_context {
116 struct xfs_trans *tp;
117 struct xfs_inode *dp; /* inode */
118 struct attrlist_cursor_kern *cursor; /* position in list */
119 char *alist; /* output buffer */
120
121 /*
122 * Abort attribute list iteration if non-zero. Can be used to pass
123 * error values to the xfs_attr_list caller.
124 */
125 int seen_enough;
126
127 ssize_t count; /* num used entries */
128 int dupcnt; /* count dup hashvals seen */
129 int bufsize; /* total buffer size */
130 int firstu; /* first used byte in buffer */
131 int flags; /* from VOP call */
132 int resynch; /* T/F: resynch with cursor */
133 put_listent_func_t put_listent; /* list output fmt function */
134 int index; /* index into output buffer */
135 } xfs_attr_list_context_t;
136
137
138 /*========================================================================
139 * Function prototypes for the kernel.
140 *========================================================================*/
141
142 /*
143 * Overall external interface routines.
144 */
145 int xfs_attr_inactive(struct xfs_inode *dp);
146 int xfs_attr_list_int_ilocked(struct xfs_attr_list_context *);
147 int xfs_attr_list_int(struct xfs_attr_list_context *);
148 int xfs_inode_hasattr(struct xfs_inode *ip);
149 int xfs_attr_get_ilocked(struct xfs_inode *ip, struct xfs_da_args *args);
150 int xfs_attr_get(struct xfs_inode *ip, const unsigned char *name,
151 unsigned char **value, int *valuelenp, int flags);
152 int xfs_attr_set(struct xfs_inode *dp, const unsigned char *name,
153 unsigned char *value, int valuelen, int flags);
154 int xfs_attr_set_args(struct xfs_da_args *args);
155 int xfs_attr_remove(struct xfs_inode *dp, const unsigned char *name, int flags);
156 int xfs_attr_remove_args(struct xfs_da_args *args);
157 int xfs_attr_list(struct xfs_inode *dp, char *buffer, int bufsize,
158 int flags, struct attrlist_cursor_kern *cursor);
159 bool xfs_attr_namecheck(const void *name, size_t length);
160
161 #endif /* __XFS_ATTR_H__ */