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 * $DragonFly: src/libexec/mknetid/hash.c,v 1.2 2003/06/17 04:27:07 dillon Exp $ 34 */ 35 36 #include <stdio.h> 37 #include <stdlib.h> 38 #include <string.h> 39 #include <sys/types.h> 40 #include "hash.h" 41 42 /* 43 * This hash function is stolen directly from the 44 * Berkeley DB package. It already exists inside libc, but 45 * it's declared static which prevents us from calling it 46 * from here. 47 */ 48 /* 49 * OZ's original sdbm hash 50 */ 51 u_int32_t 52 hash(keyarg, len) 53 const void *keyarg; 54 register size_t len; 55 { 56 register const u_char *key; 57 register size_t loop; 58 register 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 hole 256 elements. 102 */ 103 u_int32_t hashkey(key) 104 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 struct grouplist *lookup(table, key) 114 struct member_entry *table[]; 115 char *key; 116 { 117 struct member_entry *cur; 118 119 cur = table[hashkey(key)]; 120 121 while (cur) { 122 if (!strcmp(cur->key, key)) 123 return(cur->groups); 124 cur = cur->next; 125 } 126 127 return(NULL); 128 } 129 130 struct grouplist dummy = { 99999, NULL }; 131 132 /* 133 * Store an group member entry and/or update its grouplist. 134 */ 135 void mstore (table, key, gid, dup) 136 struct member_entry *table[]; 137 char *key; 138 int gid; 139 int dup; 140 { 141 struct member_entry *cur, *new; 142 struct grouplist *tmp; 143 u_int32_t i; 144 145 i = hashkey(key); 146 cur = table[i]; 147 148 if (!dup) { 149 tmp = (struct grouplist *)malloc(sizeof(struct grouplist)); 150 tmp->groupid = gid; 151 tmp->next = NULL; 152 } 153 154 /* Check if all we have to do is insert a new groupname. */ 155 while (cur) { 156 if (!dup && !strcmp(cur->key, key)) { 157 tmp->next = cur->groups; 158 cur->groups = tmp; 159 return; 160 } 161 cur = cur->next; 162 } 163 164 /* Didn't find a match -- add the whole mess to the table. */ 165 new = (struct member_entry *)malloc(sizeof(struct member_entry)); 166 new->key = strdup(key); 167 if (!dup) 168 new->groups = tmp; 169 else 170 new->groups = (struct grouplist *)&dummy; 171 new->next = table[i]; 172 table[i] = new; 173 174 return; 175 } 176