xref: /titanic_50/usr/src/uts/common/sharefs/sharetab.h (revision a237e38e9161f0acd6451439d4a7dd597e66291d)
1*a237e38eSth199096 /*
2*a237e38eSth199096  * CDDL HEADER START
3*a237e38eSth199096  *
4*a237e38eSth199096  * The contents of this file are subject to the terms of the
5*a237e38eSth199096  * Common Development and Distribution License (the "License").
6*a237e38eSth199096  * You may not use this file except in compliance with the License.
7*a237e38eSth199096  *
8*a237e38eSth199096  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9*a237e38eSth199096  * or http://www.opensolaris.org/os/licensing.
10*a237e38eSth199096  * See the License for the specific language governing permissions
11*a237e38eSth199096  * and limitations under the License.
12*a237e38eSth199096  *
13*a237e38eSth199096  * When distributing Covered Code, include this CDDL HEADER in each
14*a237e38eSth199096  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15*a237e38eSth199096  * If applicable, add the following below this CDDL HEADER, with the
16*a237e38eSth199096  * fields enclosed by brackets "[]" replaced with your own identifying
17*a237e38eSth199096  * information: Portions Copyright [yyyy] [name of copyright owner]
18*a237e38eSth199096  *
19*a237e38eSth199096  * CDDL HEADER END
20*a237e38eSth199096  */
21*a237e38eSth199096 
22*a237e38eSth199096 /*
23*a237e38eSth199096  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
24*a237e38eSth199096  * Use is subject to license terms.
25*a237e38eSth199096  */
26*a237e38eSth199096 
27*a237e38eSth199096 #ifndef _SHAREFS_SHARETAB_H
28*a237e38eSth199096 #define	_SHAREFS_SHARETAB_H
29*a237e38eSth199096 
30*a237e38eSth199096 #pragma ident	"%Z%%M%	%I%	%E% SMI"
31*a237e38eSth199096 
32*a237e38eSth199096 /*
33*a237e38eSth199096  * This header defines the glue to keeping a sharetab in memory.
34*a237e38eSth199096  * It is broken out from sharefs.h in the case that it will be
35*a237e38eSth199096  * reused in userland.
36*a237e38eSth199096  */
37*a237e38eSth199096 
38*a237e38eSth199096 /*
39*a237e38eSth199096  * Note:
40*a237e38eSth199096  * Must include share/share.h before this header.
41*a237e38eSth199096  */
42*a237e38eSth199096 
43*a237e38eSth199096 #ifdef __cplusplus
44*a237e38eSth199096 extern "C" {
45*a237e38eSth199096 #endif
46*a237e38eSth199096 
47*a237e38eSth199096 typedef struct sh_list {		/* cached share list */
48*a237e38eSth199096 	struct sh_list	*shl_next;
49*a237e38eSth199096 	share_t		*shl_sh;
50*a237e38eSth199096 } sh_list_t;
51*a237e38eSth199096 
52*a237e38eSth199096 typedef struct sharefs_hash_head {
53*a237e38eSth199096 	share_t		*ssh_sh;
54*a237e38eSth199096 	uint_t		ssh_count;
55*a237e38eSth199096 } sharefs_hash_head_t;
56*a237e38eSth199096 
57*a237e38eSth199096 #define	SHARETAB_HASHES		256
58*a237e38eSth199096 
59*a237e38eSth199096 typedef struct sharetab {
60*a237e38eSth199096 	sharefs_hash_head_t	s_buckets[SHARETAB_HASHES];
61*a237e38eSth199096 	char			*s_fstype;
62*a237e38eSth199096 	struct sharetab		*s_next;
63*a237e38eSth199096 	uint_t			s_count;
64*a237e38eSth199096 } sharetab_t;
65*a237e38eSth199096 
66*a237e38eSth199096 #define	MOD2(a, pow_of_2)	(a) & ((pow_of_2) - 1)
67*a237e38eSth199096 
68*a237e38eSth199096 /*
69*a237e38eSth199096  * Pearson's string hash
70*a237e38eSth199096  *
71*a237e38eSth199096  * See: Communications of the ACM, June 1990 Vol 33 pp 677-680
72*a237e38eSth199096  * http://www.acm.org/pubs/citations/journals/cacm/1990-33-6/p677-pearson
73*a237e38eSth199096  */
74*a237e38eSth199096 #define	SHARETAB_HASH_IT(hash, path)					\
75*a237e38eSth199096 {									\
76*a237e38eSth199096 	uint_t		key = 0x12345678;	/* arbitrary value */	\
77*a237e38eSth199096 	int		i, len;						\
78*a237e38eSth199096 									\
79*a237e38eSth199096 	len = strlen((path));						\
80*a237e38eSth199096 									\
81*a237e38eSth199096 	(hash) = MOD2((key + len), SHARETAB_HASHES);			\
82*a237e38eSth199096 									\
83*a237e38eSth199096 	for (i = 0; i < len; i++) {					\
84*a237e38eSth199096 		(hash) = MOD2(((hash) + (path)[i]), SHARETAB_HASHES);	\
85*a237e38eSth199096 		(hash) = pkp_tab[(hash)];				\
86*a237e38eSth199096 	}								\
87*a237e38eSth199096 }
88*a237e38eSth199096 
89*a237e38eSth199096 #ifdef __cplusplus
90*a237e38eSth199096 }
91*a237e38eSth199096 #endif
92*a237e38eSth199096 
93*a237e38eSth199096 #endif /* !_SHAREFS_SHARETAB_H */
94