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#ifndef lint
36static const char rcsid[] =
37  "$FreeBSD$";
38#endif /* not lint */
39
40#include <stdio.h>
41#include <stdlib.h>
42#include <string.h>
43#include <sys/types.h>
44#include "hash.h"
45
46/*
47 * This hash function is stolen directly from the
48 * Berkeley DB package. It already exists inside libc, but
49 * it's declared static which prevents us from calling it
50 * from here.
51 */
52/*
53 * OZ's original sdbm hash
54 */
55u_int32_t
56hash(const void *keyarg, size_t len)
57{
58	const u_char *key;
59	size_t loop;
60	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 hold 256 elements.
104 */
105u_int32_t
106hashkey(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). */
115char *
116lookup(struct group_entry *table[], char *key)
117{
118	struct group_entry *cur;
119
120	cur = table[hashkey(key)];
121
122	while (cur) {
123		if (!strcmp(cur->key, key))
124			return(cur->data);
125		cur = cur->next;
126	}
127
128	return(NULL);
129}
130
131/*
132 * Store an entry in the main netgroup hash table. Here's how this
133 * works: the table can only be so big when we initialize it (TABLESIZE)
134 * but the number of netgroups in the /etc/netgroup file could easily be
135 * much larger than the table. Since our hash values are adjusted to
136 * never be greater than TABLESIZE too, this means it won't be long before
137 * we find ourselves with two keys that hash to the same value.
138 *
139 * One way to deal with this is to malloc(2) a second table and start
140 * doing indirection, but this is a pain in the butt and it's not worth
141 * going to all that trouble for a dinky little program like this. Instead,
142 * we turn each table entry into a linked list and simply link keys
143 * with the same hash value together at the same index location within
144 * the table.
145 *
146 * That's a lot of comment for such a small piece of code, isn't it.
147 */
148void
149store(struct group_entry *table[], char *key, char *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
178mstore(struct member_entry *table[], char *key, char *data, char *domain)
179{
180	struct member_entry *cur, *new;
181	struct grouplist *tmp;
182	u_int32_t i;
183
184	i = hashkey(key);
185	cur = table[i];
186
187	tmp = (struct grouplist *)malloc(sizeof(struct grouplist));
188	tmp->groupname = strdup(data);
189	tmp->next = NULL;
190
191	/* Check if all we have to do is insert a new groupname. */
192	while (cur) {
193		if (!strcmp(cur->key, key)) {
194			tmp->next = cur->groups;
195			cur->groups = tmp;
196			return;
197		}
198		cur = cur->next;
199	}
200
201	/* Didn't find a match -- add the whole mess to the table. */
202	new = (struct member_entry *)malloc(sizeof(struct member_entry));
203	new->key = strdup(key);
204	new->domain = domain ? strdup(domain) : "*";
205	new->groups = tmp;
206	new->next = table[i];
207	table[i] = new;
208
209	return;
210}
211