Merge from vendor branch BINUTILS:
[dragonfly.git] / libexec / revnetgroup / 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/revnetgroup/hash.c,v 1.6 1999/08/28 00:09:47 peter Exp $
33 * $DragonFly: src/libexec/revnetgroup/hash.c,v 1.2 2003/06/17 04:27:07 dillon Exp $
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34 */
35
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36#include <stdio.h>
37#include <stdlib.h>
38#include <string.h>
39#include <sys/types.h>
40#include "hash.h"
41
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 hold 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). */
113char *lookup(table, key)
114 struct group_entry *table[];
115 char *key;
116{
117 struct group_entry *cur;
118
119 cur = table[hashkey(key)];
120
121 while (cur) {
122 if (!strcmp(cur->key, key))
123 return(cur->data);
124 cur = cur->next;
125 }
126
127 return(NULL);
128}
129
130/*
131 * Store an entry in the main netgroup hash table. Here's how this
132 * works: the table can only be so big when we initialize it (TABLESIZE)
133 * but the number of netgroups in the /etc/netgroup file could easily be
134 * much larger than the table. Since our hash values are adjusted to
135 * never be greater than TABLESIZE too, this means it won't be long before
136 * we find ourselves with two keys that hash to the same value.
137 *
138 * One way to deal with this is to malloc(2) a second table and start
139 * doing indirection, but this is a pain in the butt and it's not worth
140 * going to all that trouble for a dinky little program like this. Instead,
141 * we turn each table entry into a linked list and simply link keys
142 * with the same hash value together at the same index location within
143 * the table.
144 *
145 * That's a lot of comment for such a small piece of code, isn't it.
146 */
147void store (table, key, data)
148 struct group_entry *table[];
149 char *key, *data;
150{
151 struct group_entry *new;
152 u_int32_t i;
153
154 i = hashkey(key);
155
156 new = (struct group_entry *)malloc(sizeof(struct group_entry));
157 new->key = strdup(key);
158 new->data = strdup(data);
159 new->next = table[i];
160 table[i] = new;
161
162 return;
163}
164
165/*
166 * Store a group member entry and/or update its grouplist. This is
167 * a bit more complicated than the previous function since we have to
168 * maintain not only the hash table of group members, each group member
169 * structure also has a linked list of groups hung off it. If handed
170 * a member name that we haven't encountered before, we have to do
171 * two things: add that member to the table (possibly hanging them
172 * off the end of a linked list, as above), and add a group name to
173 * the member's grouplist list. If we're handed a name that already has
174 * an entry in the table, then we just have to do one thing, which is
175 * to update its grouplist.
176 */
177void mstore (table, key, data, domain)
178 struct member_entry *table[];
179 char *key, *data, *domain;
180{
181 struct member_entry *cur, *new;
182 struct grouplist *tmp;
183 u_int32_t i;
184
185 i = hashkey(key);
186 cur = table[i];
187
188 tmp = (struct grouplist *)malloc(sizeof(struct grouplist));
189 tmp->groupname = strdup(data);
190 tmp->next = NULL;
191
192 /* Check if all we have to do is insert a new groupname. */
193 while (cur) {
194 if (!strcmp(cur->key, key)) {
195 tmp->next = cur->groups;
196 cur->groups = tmp;
197 return;
198 }
199 cur = cur->next;
200 }
201
202 /* Didn't find a match -- add the whole mess to the table. */
203 new = (struct member_entry *)malloc(sizeof(struct member_entry));
204 new->key = strdup(key);
205 new->domain = domain ? strdup(domain) : "*";
206 new->groups = tmp;
207 new->next = table[i];
208 table[i] = new;
209
210 return;
211}