1 /*-
2 * SPDX-License-Identifier: BSD-4-Clause
3 *
4 * Copyright (c) 1995
5 * Bill Paul <[email protected]>. 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
36 static 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 */
55 u_int32_t
hash(const void * keyarg,size_t len)56 hash(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 */
105 u_int32_t
hashkey(char * key)106 hashkey(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). */
115 char *
lookup(struct group_entry * table[],char * key)116 lookup(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 */
148 void
store(struct group_entry * table[],char * key,char * data)149 store(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 */
177 void
mstore(struct member_entry * table[],char * key,char * data,char * domain)178 mstore(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