ddb(4): mention 'show ktr' command
[dragonfly.git] / libexec / mknetid / hash.c
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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.
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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 $
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34 */
35
36#include <stdio.h>
37#include <stdlib.h>
38#include <string.h>
39#include <sys/types.h>
40#include "hash.h"
41
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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 */
51u_int32_t
52hash(keyarg, len)
53 const void *keyarg;
54 register size_t len;
55{
56 register const u_char *key;
57 register size_t loop;
58 register u_int32_t h;
59
60#define HASHC h = *key++ + 65599 * h
61
62 h = 0;
63 key = keyarg;
64 if (len > 0) {
65 loop = (len + 8 - 1) >> 3;
66
67 switch (len & (8 - 1)) {
68 case 0:
69 do {
70 HASHC;
71 /* FALLTHROUGH */
72 case 7:
73 HASHC;
74 /* FALLTHROUGH */
75 case 6:
76 HASHC;
77 /* FALLTHROUGH */
78 case 5:
79 HASHC;
80 /* FALLTHROUGH */
81 case 4:
82 HASHC;
83 /* FALLTHROUGH */
84 case 3:
85 HASHC;
86 /* FALLTHROUGH */
87 case 2:
88 HASHC;
89 /* FALLTHROUGH */
90 case 1:
91 HASHC;
92 } while (--loop);
93 }
94 }
95 return (h);
96}
97
98/*
99 * Generate a hash value for a given key (character string).
100 * We mask off all but the lower 8 bits since our table array
101 * can only hole 256 elements.
102 */
103u_int32_t hashkey(key)
104 char *key;
105{
106
107 if (key == NULL)
108 return (-1);
109 return(hash((void *)key, strlen(key)) & HASH_MASK);
110}
111
112/* Find an entry in the hash table (may be hanging off a linked list). */
113struct grouplist *lookup(table, key)
114 struct member_entry *table[];
115 char *key;
116{
117 struct member_entry *cur;
118
119 cur = table[hashkey(key)];
120
121 while (cur) {
122 if (!strcmp(cur->key, key))
123 return(cur->groups);
124 cur = cur->next;
125 }
126
127 return(NULL);
128}
129
130struct grouplist dummy = { 99999, NULL };
131
132/*
133 * Store an group member entry and/or update its grouplist.
134 */
135void mstore (table, key, gid, dup)
136 struct member_entry *table[];
137 char *key;
138 int gid;
139 int dup;
140{
141 struct member_entry *cur, *new;
142 struct grouplist *tmp;
143 u_int32_t i;
144
145 i = hashkey(key);
146 cur = table[i];
147
148 if (!dup) {
149 tmp = (struct grouplist *)malloc(sizeof(struct grouplist));
150 tmp->groupid = gid;
151 tmp->next = NULL;
152 }
153
154 /* Check if all we have to do is insert a new groupname. */
155 while (cur) {
156 if (!dup && !strcmp(cur->key, key)) {
157 tmp->next = cur->groups;
158 cur->groups = tmp;
159 return;
160 }
161 cur = cur->next;
162 }
163
164 /* Didn't find a match -- add the whole mess to the table. */
165 new = (struct member_entry *)malloc(sizeof(struct member_entry));
166 new->key = strdup(key);
167 if (!dup)
168 new->groups = tmp;
169 else
170 new->groups = (struct grouplist *)&dummy;
171 new->next = table[i];
172 table[i] = new;
173
174 return;
175}