amr.4: Remove an unneeded .Pp
[dragonfly.git] / libexec / mknetid / hash.c
CommitLineData
984263bc
MD
1/*
2 * Copyright (c) 1995
3 * Bill Paul <wpaul@ctr.columbia.edu>. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by Bill Paul.
16 * 4. Neither the name of the author nor the names of any co-contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY Bill Paul AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL Bill Paul OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
1de703da
MD
31 *
32 * $FreeBSD: src/libexec/mknetid/hash.c,v 1.5 1999/08/28 00:09:40 peter Exp $
33 * $DragonFly: src/libexec/mknetid/hash.c,v 1.2 2003/06/17 04:27:07 dillon Exp $
984263bc
MD
34 */
35
36#include <stdio.h>
37#include <stdlib.h>
38#include <string.h>
39#include <sys/types.h>
40#include "hash.h"
41
984263bc
MD
42/*
43 * This hash function is stolen directly from the
44 * Berkeley DB package. It already exists inside libc, but
45 * it's declared static which prevents us from calling it
46 * from here.
47 */
48/*
49 * OZ's original sdbm hash
50 */
06a0ed23
SW
51static u_int32_t
52hash(const void *keyarg, size_t len)
984263bc 53{
06a0ed23
SW
54 const u_char *key;
55 size_t loop;
56 u_int32_t h;
984263bc
MD
57
58#define HASHC h = *key++ + 65599 * h
59
60 h = 0;
61 key = keyarg;
62 if (len > 0) {
63 loop = (len + 8 - 1) >> 3;
64
65 switch (len & (8 - 1)) {
66 case 0:
67 do {
68 HASHC;
69 /* FALLTHROUGH */
70 case 7:
71 HASHC;
72 /* FALLTHROUGH */
73 case 6:
74 HASHC;
75 /* FALLTHROUGH */
76 case 5:
77 HASHC;
78 /* FALLTHROUGH */
79 case 4:
80 HASHC;
81 /* FALLTHROUGH */
82 case 3:
83 HASHC;
84 /* FALLTHROUGH */
85 case 2:
86 HASHC;
87 /* FALLTHROUGH */
88 case 1:
89 HASHC;
90 } while (--loop);
91 }
92 }
93 return (h);
94}
95
96/*
97 * Generate a hash value for a given key (character string).
98 * We mask off all but the lower 8 bits since our table array
99 * can only hole 256 elements.
100 */
06a0ed23
SW
101static u_int32_t
102hashkey(char *key)
984263bc
MD
103{
104
105 if (key == NULL)
106 return (-1);
107 return(hash((void *)key, strlen(key)) & HASH_MASK);
108}
109
110/* Find an entry in the hash table (may be hanging off a linked list). */
06a0ed23
SW
111struct grouplist *
112lookup(struct member_entry *table[], char *key)
984263bc
MD
113{
114 struct member_entry *cur;
115
116 cur = table[hashkey(key)];
117
118 while (cur) {
119 if (!strcmp(cur->key, key))
120 return(cur->groups);
121 cur = cur->next;
122 }
123
124 return(NULL);
125}
126
127struct grouplist dummy = { 99999, NULL };
128
129/*
130 * Store an group member entry and/or update its grouplist.
131 */
06a0ed23
SW
132void
133mstore(struct member_entry *table[], char *key, int gid, int dup)
984263bc
MD
134{
135 struct member_entry *cur, *new;
06a0ed23 136 struct grouplist *tmp = NULL;
984263bc
MD
137 u_int32_t i;
138
139 i = hashkey(key);
140 cur = table[i];
141
142 if (!dup) {
143 tmp = (struct grouplist *)malloc(sizeof(struct grouplist));
144 tmp->groupid = gid;
145 tmp->next = NULL;
146 }
147
148 /* Check if all we have to do is insert a new groupname. */
149 while (cur) {
150 if (!dup && !strcmp(cur->key, key)) {
151 tmp->next = cur->groups;
152 cur->groups = tmp;
153 return;
154 }
155 cur = cur->next;
156 }
157
158 /* Didn't find a match -- add the whole mess to the table. */
159 new = (struct member_entry *)malloc(sizeof(struct member_entry));
160 new->key = strdup(key);
161 if (!dup)
162 new->groups = tmp;
163 else
164 new->groups = (struct grouplist *)&dummy;
165 new->next = table[i];
166 table[i] = new;
167
168 return;
169}