Initial import from FreeBSD RELENG_4:
[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.
31 */
32
33#include <stdio.h>
34#include <stdlib.h>
35#include <string.h>
36#include <sys/types.h>
37#include "hash.h"
38
39#ifndef lint
40static const char rcsid[] =
41 "$FreeBSD: src/libexec/mknetid/hash.c,v 1.5 1999/08/28 00:09:40 peter Exp $";
42#endif /* not lint */
43
44/*
45 * This hash function is stolen directly from the
46 * Berkeley DB package. It already exists inside libc, but
47 * it's declared static which prevents us from calling it
48 * from here.
49 */
50/*
51 * OZ's original sdbm hash
52 */
53u_int32_t
54hash(keyarg, len)
55 const void *keyarg;
56 register size_t len;
57{
58 register const u_char *key;
59 register size_t loop;
60 register u_int32_t h;
61
62#define HASHC h = *key++ + 65599 * h
63
64 h = 0;
65 key = keyarg;
66 if (len > 0) {
67 loop = (len + 8 - 1) >> 3;
68
69 switch (len & (8 - 1)) {
70 case 0:
71 do {
72 HASHC;
73 /* FALLTHROUGH */
74 case 7:
75 HASHC;
76 /* FALLTHROUGH */
77 case 6:
78 HASHC;
79 /* FALLTHROUGH */
80 case 5:
81 HASHC;
82 /* FALLTHROUGH */
83 case 4:
84 HASHC;
85 /* FALLTHROUGH */
86 case 3:
87 HASHC;
88 /* FALLTHROUGH */
89 case 2:
90 HASHC;
91 /* FALLTHROUGH */
92 case 1:
93 HASHC;
94 } while (--loop);
95 }
96 }
97 return (h);
98}
99
100/*
101 * Generate a hash value for a given key (character string).
102 * We mask off all but the lower 8 bits since our table array
103 * can only hole 256 elements.
104 */
105u_int32_t hashkey(key)
106 char *key;
107{
108
109 if (key == NULL)
110 return (-1);
111 return(hash((void *)key, strlen(key)) & HASH_MASK);
112}
113
114/* Find an entry in the hash table (may be hanging off a linked list). */
115struct grouplist *lookup(table, key)
116 struct member_entry *table[];
117 char *key;
118{
119 struct member_entry *cur;
120
121 cur = table[hashkey(key)];
122
123 while (cur) {
124 if (!strcmp(cur->key, key))
125 return(cur->groups);
126 cur = cur->next;
127 }
128
129 return(NULL);
130}
131
132struct grouplist dummy = { 99999, NULL };
133
134/*
135 * Store an group member entry and/or update its grouplist.
136 */
137void mstore (table, key, gid, dup)
138 struct member_entry *table[];
139 char *key;
140 int gid;
141 int dup;
142{
143 struct member_entry *cur, *new;
144 struct grouplist *tmp;
145 u_int32_t i;
146
147 i = hashkey(key);
148 cur = table[i];
149
150 if (!dup) {
151 tmp = (struct grouplist *)malloc(sizeof(struct grouplist));
152 tmp->groupid = gid;
153 tmp->next = NULL;
154 }
155
156 /* Check if all we have to do is insert a new groupname. */
157 while (cur) {
158 if (!dup && !strcmp(cur->key, key)) {
159 tmp->next = cur->groups;
160 cur->groups = tmp;
161 return;
162 }
163 cur = cur->next;
164 }
165
166 /* Didn't find a match -- add the whole mess to the table. */
167 new = (struct member_entry *)malloc(sizeof(struct member_entry));
168 new->key = strdup(key);
169 if (!dup)
170 new->groups = tmp;
171 else
172 new->groups = (struct grouplist *)&dummy;
173 new->next = table[i];
174 table[i] = new;
175
176 return;
177}