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 * $FreeBSD: src/libexec/mknetid/hash.c,v 1.5 1999/08/28 00:09:40 peter Exp $
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 */
50 static u_int32_t
hash(const void * keyarg,size_t len)51 hash(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 hole 256 elements.
99 */
100 static u_int32_t
hashkey(char * key)101 hashkey(char *key)
102 {
103
104 if (key == NULL)
105 return (-1);
106 return(hash(key, strlen(key)) & HASH_MASK);
107 }
108
109 /* Find an entry in the hash table (may be hanging off a linked list). */
110 struct grouplist *
lookup(struct member_entry * table[],char * key)111 lookup(struct member_entry *table[], char *key)
112 {
113 struct member_entry *cur;
114
115 cur = table[hashkey(key)];
116
117 while (cur) {
118 if (!strcmp(cur->key, key))
119 return(cur->groups);
120 cur = cur->next;
121 }
122
123 return(NULL);
124 }
125
126 struct grouplist dummy = { 99999, NULL };
127
128 /*
129 * Store an group member entry and/or update its grouplist.
130 */
131 void
mstore(struct member_entry * table[],char * key,int gid,int dup)132 mstore(struct member_entry *table[], char *key, int gid, int dup)
133 {
134 struct member_entry *cur, *new;
135 struct grouplist *tmp = NULL;
136 u_int32_t i;
137
138 i = hashkey(key);
139 cur = table[i];
140
141 if (!dup) {
142 tmp = (struct grouplist *)malloc(sizeof(struct grouplist));
143 tmp->groupid = gid;
144 tmp->next = NULL;
145 }
146
147 /* Check if all we have to do is insert a new groupname. */
148 while (cur) {
149 if (!dup && !strcmp(cur->key, key)) {
150 tmp->next = cur->groups;
151 cur->groups = tmp;
152 return;
153 }
154 cur = cur->next;
155 }
156
157 /* Didn't find a match -- add the whole mess to the table. */
158 new = (struct member_entry *)malloc(sizeof(struct member_entry));
159 new->key = strdup(key);
160 if (!dup)
161 new->groups = tmp;
162 else
163 new->groups = (struct grouplist *)&dummy;
164 new->next = table[i];
165 table[i] = new;
166
167 return;
168 }
169