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
34 static 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 */
53 u_int32_t
hash(const void * keyarg,size_t len)54 hash(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 */
103 u_int32_t
hashkey(char * key)104 hashkey(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). */
113 char *
lookup(struct group_entry * table[],char * key)114 lookup(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 */
146 void
store(struct group_entry * table[],char * key,char * data)147 store(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 */
175 void
mstore(struct member_entry * table[],char * key,char * data,char * domain)176 mstore(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