3 * Bill Paul <wpaul@ctr.columbia.edu>. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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9 * notice, this list of conditions and the following disclaimer.
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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.
20 * THIS SOFTWARE IS PROVIDED BY Bill Paul AND CONTRIBUTORS ``AS IS'' AND
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34 static const char rcsid[] =
41 #include <sys/types.h>
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
51 * OZ's original sdbm hash
54 hash(const void *keyarg, size_t len)
60 #define HASHC h = *key++ + 65599 * h
65 loop = (len + 8 - 1) >> 3;
67 switch (len & (8 - 1)) {
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.
109 return(hash((void *)key, strlen(key)) & HASH_MASK);
112 /* Find an entry in the hash table (may be hanging off a linked list). */
114 lookup(struct group_entry *table[], char *key)
116 struct group_entry *cur;
118 cur = table[hashkey(key)];
121 if (!strcmp(cur->key, key))
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.
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
144 * That's a lot of comment for such a small piece of code, isn't it.
147 store(struct group_entry *table[], char *key, char *data)
149 struct group_entry *new;
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];
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.
176 mstore(struct member_entry *table[], char *key, char *data, char *domain)
178 struct member_entry *cur, *new;
179 struct grouplist *tmp;
185 tmp = (struct grouplist *)malloc(sizeof(struct grouplist));
186 tmp->groupname = strdup(data);
189 /* Check if all we have to do is insert a new groupname. */
191 if (!strcmp(cur->key, key)) {
192 tmp->next = cur->groups;
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) : "*";
204 new->next = table[i];