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#ifndef lint
34static const char rcsid[] =
35  "$FreeBSD$";
36#endif /* not lint */
37
38#include <stdio.h>
39#include <stdlib.h>
40#include <string.h>
41#include <sys/types.h>
42#include "hash.h"
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(const void *keyarg, size_t len)
55{
56	const u_char *key;
57	size_t loop;
58	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
104hashkey(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 *
114lookup(struct group_entry *table[], char *key)
115{
116	struct group_entry *cur;
117
118	cur = table[hashkey(key)];
119
120	while (cur) {
121		if (!strcmp(cur->key, key))
122			return(cur->data);
123		cur = cur->next;
124	}
125
126	return(NULL);
127}
128
129/*
130 * Store an entry in the main netgroup hash table. Here's how this
131 * works: the table can only be so big when we initialize it (TABLESIZE)
132 * but the number of netgroups in the /etc/netgroup file could easily be
133 * much larger than the table. Since our hash values are adjusted to
134 * never be greater than TABLESIZE too, this means it won't be long before
135 * we find ourselves with two keys that hash to the same value.
136 *
137 * One way to deal with this is to malloc(2) a second table and start
138 * doing indirection, but this is a pain in the butt and it's not worth
139 * going to all that trouble for a dinky little program like this. Instead,
140 * we turn each table entry into a linked list and simply link keys
141 * with the same hash value together at the same index location within
142 * the table.
143 *
144 * That's a lot of comment for such a small piece of code, isn't it.
145 */
146void
147store(struct group_entry *table[], char *key, char *data)
148{
149	struct group_entry *new;
150	u_int32_t i;
151
152	i = hashkey(key);
153
154	new = (struct group_entry *)malloc(sizeof(struct group_entry));
155	new->key = strdup(key);
156	new->data = strdup(data);
157	new->next = table[i];
158	table[i] = new;
159
160	return;
161}
162
163/*
164 * Store a group member entry and/or update its grouplist. This is
165 * a bit more complicated than the previous function since we have to
166 * maintain not only the hash table of group members, each group member
167 * structure also has a linked list of groups hung off it. If handed
168 * a member name that we haven't encountered before, we have to do
169 * two things: add that member to the table (possibly hanging them
170 * off the end of a linked list, as above), and add a group name to
171 * the member's grouplist list. If we're handed a name that already has
172 * an entry in the table, then we just have to do one thing, which is
173 * to update its grouplist.
174 */
175void
176mstore(struct member_entry *table[], char *key, char *data, char *domain)
177{
178	struct member_entry *cur, *new;
179	struct grouplist *tmp;
180	u_int32_t i;
181
182	i = hashkey(key);
183	cur = table[i];
184
185	tmp = (struct grouplist *)malloc(sizeof(struct grouplist));
186	tmp->groupname = strdup(data);
187	tmp->next = NULL;
188
189	/* Check if all we have to do is insert a new groupname. */
190	while (cur) {
191		if (!strcmp(cur->key, key)) {
192			tmp->next = cur->groups;
193			cur->groups = tmp;
194			return;
195		}
196		cur = cur->next;
197	}
198
199	/* Didn't find a match -- add the whole mess to the table. */
200	new = (struct member_entry *)malloc(sizeof(struct member_entry));
201	new->key = strdup(key);
202	new->domain = domain ? strdup(domain) : "*";
203	new->groups = tmp;
204	new->next = table[i];
205	table[i] = new;
206
207	return;
208}
209