1/*
  2 * Copyright (c) 2000,2002-2003,2005 Silicon Graphics, Inc.
  3 * All Rights Reserved.
  4 *
  5 * This program is free software; you can redistribute it and/or
  6 * modify it under the terms of the GNU General Public License as
  7 * published by the Free Software Foundation.
  8 *
  9 * This program is distributed in the hope that it would be useful,
 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 12 * GNU General Public License for more details.
 13 *
 14 * You should have received a copy of the GNU General Public License
 15 * along with this program; if not, write the Free Software Foundation,
 16 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 17 */
 18#ifndef __XFS_ATTR_H__
 19#define	__XFS_ATTR_H__
 20
 21struct xfs_inode;
 22struct xfs_da_args;
 23struct xfs_attr_list_context;
 24
 25/*
 26 * Large attribute lists are structured around Btrees where all the data
 27 * elements are in the leaf nodes.  Attribute names are hashed into an int,
 28 * then that int is used as the index into the Btree.  Since the hashval
 29 * of an attribute name may not be unique, we may have duplicate keys.
 30 * The internal links in the Btree are logical block offsets into the file.
 31 *
 32 * Small attribute lists use a different format and are packed as tightly
 33 * as possible so as to fit into the literal area of the inode.
 34 */
 35
 36/*========================================================================
 37 * External interfaces
 38 *========================================================================*/
 39
 40
 41#define ATTR_DONTFOLLOW	0x0001	/* -- unused, from IRIX -- */
 42#define ATTR_ROOT	0x0002	/* use attrs in root (trusted) namespace */
 43#define ATTR_TRUST	0x0004	/* -- unused, from IRIX -- */
 44#define ATTR_SECURE	0x0008	/* use attrs in security namespace */
 45#define ATTR_CREATE	0x0010	/* pure create: fail if attr already exists */
 46#define ATTR_REPLACE	0x0020	/* pure set: fail if attr does not exist */
 47
 48#define ATTR_KERNOTIME	0x1000	/* [kernel] don't update inode timestamps */
 49#define ATTR_KERNOVAL	0x2000	/* [kernel] get attr size only, not value */
 50
 51#define XFS_ATTR_FLAGS \
 52	{ ATTR_DONTFOLLOW, 	"DONTFOLLOW" }, \
 53	{ ATTR_ROOT,		"ROOT" }, \
 54	{ ATTR_TRUST,		"TRUST" }, \
 55	{ ATTR_SECURE,		"SECURE" }, \
 56	{ ATTR_CREATE,		"CREATE" }, \
 57	{ ATTR_REPLACE,		"REPLACE" }, \
 58	{ ATTR_KERNOTIME,	"KERNOTIME" }, \
 59	{ ATTR_KERNOVAL,	"KERNOVAL" }
 60
 61/*
 62 * The maximum size (into the kernel or returned from the kernel) of an
 63 * attribute value or the buffer used for an attr_list() call.  Larger
 64 * sizes will result in an ERANGE return code.
 65 */
 66#define	ATTR_MAX_VALUELEN	(64*1024)	/* max length of a value */
 67
 68/*
 69 * Define how lists of attribute names are returned to the user from
 70 * the attr_list() call.  A large, 32bit aligned, buffer is passed in
 71 * along with its size.  We put an array of offsets at the top that each
 72 * reference an attrlist_ent_t and pack the attrlist_ent_t's at the bottom.
 73 */
 74typedef struct attrlist {
 75	__s32	al_count;	/* number of entries in attrlist */
 76	__s32	al_more;	/* T/F: more attrs (do call again) */
 77	__s32	al_offset[1];	/* byte offsets of attrs [var-sized] */
 78} attrlist_t;
 79
 80/*
 81 * Show the interesting info about one attribute.  This is what the
 82 * al_offset[i] entry points to.
 83 */
 84typedef struct attrlist_ent {	/* data from attr_list() */
 85	__u32	a_valuelen;	/* number bytes in value of attr */
 86	char	a_name[1];	/* attr name (NULL terminated) */
 87} attrlist_ent_t;
 88
 89/*
 90 * Given a pointer to the (char*) buffer containing the attr_list() result,
 91 * and an index, return a pointer to the indicated attribute in the buffer.
 92 */
 93#define	ATTR_ENTRY(buffer, index)		\
 94	((attrlist_ent_t *)			\
 95	 &((char *)buffer)[ ((attrlist_t *)(buffer))->al_offset[index] ])
 96
 97/*
 98 * Kernel-internal version of the attrlist cursor.
 99 */
100typedef struct attrlist_cursor_kern {
101	__u32	hashval;	/* hash value of next entry to add */
102	__u32	blkno;		/* block containing entry (suggestion) */
103	__u32	offset;		/* offset in list of equal-hashvals */
104	__u16	pad1;		/* padding to match user-level */
105	__u8	pad2;		/* padding to match user-level */
106	__u8	initted;	/* T/F: cursor has been initialized */
107} attrlist_cursor_kern_t;
108
109
110/*========================================================================
111 * Structure used to pass context around among the routines.
112 *========================================================================*/
113
114
115typedef int (*put_listent_func_t)(struct xfs_attr_list_context *, int,
116			      unsigned char *, int, int, unsigned char *);
117
118typedef struct xfs_attr_list_context {
119	struct xfs_inode		*dp;		/* inode */
120	struct attrlist_cursor_kern	*cursor;	/* position in list */
121	char				*alist;		/* output buffer */
122	int				seen_enough;	/* T/F: seen enough of list? */
123	ssize_t				count;		/* num used entries */
124	int				dupcnt;		/* count dup hashvals seen */
125	int				bufsize;	/* total buffer size */
126	int				firstu;		/* first used byte in buffer */
127	int				flags;		/* from VOP call */
128	int				resynch;	/* T/F: resynch with cursor */
129	int				put_value;	/* T/F: need value for listent */
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_rmtval_get(struct xfs_da_args *args);
144int xfs_attr_list_int(struct xfs_attr_list_context *);
145
146#endif	/* __XFS_ATTR_H__ */