/*- * SPDX-License-Identifier: BSD-4-Clause * * Copyright (c) 1995 * Bill Paul <wpaul@ctr.columbia.edu>. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by Bill Paul. * 4. Neither the name of the author nor the names of any co-contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY Bill Paul AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL Bill Paul OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #include "hash.h" /* * This hash function is stolen directly from the * Berkeley DB package. It already exists inside libc, but * it's declared static which prevents us from calling it * from here. */ /* * OZ's original sdbm hash */ u_int32_t hash(const void *keyarg, size_t len) { const u_char *key; size_t loop; u_int32_t h; #define HASHC h = *key++ + 65599 * h h = 0; key = keyarg; if (len > 0) { loop = (len + 8 - 1) >> 3; switch (len & (8 - 1)) { case 0: do { HASHC; /* FALLTHROUGH */ case 7: HASHC; /* FALLTHROUGH */ case 6: HASHC; /* FALLTHROUGH */ case 5: HASHC; /* FALLTHROUGH */ case 4: HASHC; /* FALLTHROUGH */ case 3: HASHC; /* FALLTHROUGH */ case 2: HASHC; /* FALLTHROUGH */ case 1: HASHC; } while (--loop); } } return (h); } /* * Generate a hash value for a given key (character string). * We mask off all but the lower 8 bits since our table array * can only hold 256 elements. */ u_int32_t hashkey(char *key) { if (key == NULL) return (-1); return(hash((void *)key, strlen(key)) & HASH_MASK); } /* Find an entry in the hash table (may be hanging off a linked list). */ char * lookup(struct group_entry *table[], char *key) { struct group_entry *cur; cur = table[hashkey(key)]; while (cur) { if (!strcmp(cur->key, key)) return(cur->data); cur = cur->next; } return(NULL); } /* * Store an entry in the main netgroup hash table. Here's how this * works: the table can only be so big when we initialize it (TABLESIZE) * but the number of netgroups in the /etc/netgroup file could easily be * much larger than the table. Since our hash values are adjusted to * never be greater than TABLESIZE too, this means it won't be long before * we find ourselves with two keys that hash to the same value. * * One way to deal with this is to malloc(2) a second table and start * doing indirection, but this is a pain in the butt and it's not worth * going to all that trouble for a dinky little program like this. Instead, * we turn each table entry into a linked list and simply link keys * with the same hash value together at the same index location within * the table. * * That's a lot of comment for such a small piece of code, isn't it. */ void store(struct group_entry *table[], char *key, char *data) { struct group_entry *new; u_int32_t i; i = hashkey(key); new = (struct group_entry *)malloc(sizeof(struct group_entry)); new->key = strdup(key); new->data = strdup(data); new->next = table[i]; table[i] = new; return; } /* * Store a group member entry and/or update its grouplist. This is * a bit more complicated than the previous function since we have to * maintain not only the hash table of group members, each group member * structure also has a linked list of groups hung off it. If handed * a member name that we haven't encountered before, we have to do * two things: add that member to the table (possibly hanging them * off the end of a linked list, as above), and add a group name to * the member's grouplist list. If we're handed a name that already has * an entry in the table, then we just have to do one thing, which is * to update its grouplist. */ void mstore(struct member_entry *table[], char *key, char *data, char *domain) { struct member_entry *cur, *new; struct grouplist *tmp; u_int32_t i; i = hashkey(key); cur = table[i]; tmp = (struct grouplist *)malloc(sizeof(struct grouplist)); tmp->groupname = strdup(data); tmp->next = NULL; /* Check if all we have to do is insert a new groupname. */ while (cur) { if (!strcmp(cur->key, key)) { tmp->next = cur->groups; cur->groups = tmp; return; } cur = cur->next; } /* Didn't find a match -- add the whole mess to the table. */ new = (struct member_entry *)malloc(sizeof(struct member_entry)); new->key = strdup(key); new->domain = domain ? strdup(domain) : "*"; new->groups = tmp; new->next = table[i]; table[i] = new; return; }
