1/*-
2 * SPDX-License-Identifier: BSD-4-Clause
3 *
4 * Copyright (c) 1995
5 *	Bill Paul <wpaul@ctr.columbia.edu>.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 *    must display the following acknowledgement:
17 *	This product includes software developed by Bill Paul.
18 * 4. Neither the name of the author nor the names of any co-contributors
19 *    may be used to endorse or promote products derived from this software
20 *    without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY Bill Paul AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL Bill Paul OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35#include <stdio.h>
36#include <stdlib.h>
37#include <string.h>
38#include <sys/types.h>
39#include "hash.h"
40
41/*
42 * This hash function is stolen directly from the
43 * Berkeley DB package. It already exists inside libc, but
44 * it's declared static which prevents us from calling it
45 * from here.
46 */
47/*
48 * OZ's original sdbm hash
49 */
50u_int32_t
51hash(const void *keyarg, size_t len)
52{
53	const u_char *key;
54	size_t loop;
55	u_int32_t h;
56
57#define HASHC   h = *key++ + 65599 * h
58
59	h = 0;
60	key = keyarg;
61	if (len > 0) {
62		loop = (len + 8 - 1) >> 3;
63
64		switch (len & (8 - 1)) {
65		case 0:
66			do {
67				HASHC;
68				/* FALLTHROUGH */
69		case 7:
70				HASHC;
71				/* FALLTHROUGH */
72		case 6:
73				HASHC;
74				/* FALLTHROUGH */
75		case 5:
76				HASHC;
77				/* FALLTHROUGH */
78		case 4:
79				HASHC;
80				/* FALLTHROUGH */
81		case 3:
82				HASHC;
83				/* FALLTHROUGH */
84		case 2:
85				HASHC;
86				/* FALLTHROUGH */
87		case 1:
88				HASHC;
89			} while (--loop);
90		}
91	}
92	return (h);
93}
94
95/*
96 * Generate a hash value for a given key (character string).
97 * We mask off all but the lower 8 bits since our table array
98 * can only hold 256 elements.
99 */
100u_int32_t
101hashkey(char *key)
102{
103
104	if (key == NULL)
105		return (-1);
106	return(hash((void *)key, strlen(key)) & HASH_MASK);
107}
108
109/* Find an entry in the hash table (may be hanging off a linked list). */
110char *
111lookup(struct group_entry *table[], char *key)
112{
113	struct group_entry *cur;
114
115	cur = table[hashkey(key)];
116
117	while (cur) {
118		if (!strcmp(cur->key, key))
119			return(cur->data);
120		cur = cur->next;
121	}
122
123	return(NULL);
124}
125
126/*
127 * Store an entry in the main netgroup hash table. Here's how this
128 * works: the table can only be so big when we initialize it (TABLESIZE)
129 * but the number of netgroups in the /etc/netgroup file could easily be
130 * much larger than the table. Since our hash values are adjusted to
131 * never be greater than TABLESIZE too, this means it won't be long before
132 * we find ourselves with two keys that hash to the same value.
133 *
134 * One way to deal with this is to malloc(2) a second table and start
135 * doing indirection, but this is a pain in the butt and it's not worth
136 * going to all that trouble for a dinky little program like this. Instead,
137 * we turn each table entry into a linked list and simply link keys
138 * with the same hash value together at the same index location within
139 * the table.
140 *
141 * That's a lot of comment for such a small piece of code, isn't it.
142 */
143void
144store(struct group_entry *table[], char *key, char *data)
145{
146	struct group_entry *new;
147	u_int32_t i;
148
149	i = hashkey(key);
150
151	new = (struct group_entry *)malloc(sizeof(struct group_entry));
152	new->key = strdup(key);
153	new->data = strdup(data);
154	new->next = table[i];
155	table[i] = new;
156
157	return;
158}
159
160/*
161 * Store a group member entry and/or update its grouplist. This is
162 * a bit more complicated than the previous function since we have to
163 * maintain not only the hash table of group members, each group member
164 * structure also has a linked list of groups hung off it. If handed
165 * a member name that we haven't encountered before, we have to do
166 * two things: add that member to the table (possibly hanging them
167 * off the end of a linked list, as above), and add a group name to
168 * the member's grouplist list. If we're handed a name that already has
169 * an entry in the table, then we just have to do one thing, which is
170 * to update its grouplist.
171 */
172void
173mstore(struct member_entry *table[], char *key, char *data, char *domain)
174{
175	struct member_entry *cur, *new;
176	struct grouplist *tmp;
177	u_int32_t i;
178
179	i = hashkey(key);
180	cur = table[i];
181
182	tmp = (struct grouplist *)malloc(sizeof(struct grouplist));
183	tmp->groupname = strdup(data);
184	tmp->next = NULL;
185
186	/* Check if all we have to do is insert a new groupname. */
187	while (cur) {
188		if (!strcmp(cur->key, key)) {
189			tmp->next = cur->groups;
190			cur->groups = tmp;
191			return;
192		}
193		cur = cur->next;
194	}
195
196	/* Didn't find a match -- add the whole mess to the table. */
197	new = (struct member_entry *)malloc(sizeof(struct member_entry));
198	new->key = strdup(key);
199	new->domain = domain ? strdup(domain) : "*";
200	new->groups = tmp;
201	new->next = table[i];
202	table[i] = new;
203
204	return;
205}
206