1 /*- 2 * SPDX-License-Identifier: BSD-4-Clause 3 * 4 * Copyright (c) 1995 5 * Bill Paul <wpaul@ctr.columbia.edu>. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by Bill Paul. 18 * 4. Neither the name of the author nor the names of any co-contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY Bill Paul AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL Bill Paul OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #ifndef lint 36 static const char rcsid[] = 37 "$FreeBSD$"; 38 #endif /* not lint */ 39 40 #include <stdio.h> 41 #include <stdlib.h> 42 #include <string.h> 43 #include <sys/types.h> 44 #include "hash.h" 45 46 /* 47 * This hash function is stolen directly from the 48 * Berkeley DB package. It already exists inside libc, but 49 * it's declared static which prevents us from calling it 50 * from here. 51 */ 52 /* 53 * OZ's original sdbm hash 54 */ 55 u_int32_t 56 hash(const void *keyarg, size_t len) 57 { 58 const u_char *key; 59 size_t loop; 60 u_int32_t h; 61 62 #define HASHC h = *key++ + 65599 * h 63 64 h = 0; 65 key = keyarg; 66 if (len > 0) { 67 loop = (len + 8 - 1) >> 3; 68 69 switch (len & (8 - 1)) { 70 case 0: 71 do { 72 HASHC; 73 /* FALLTHROUGH */ 74 case 7: 75 HASHC; 76 /* FALLTHROUGH */ 77 case 6: 78 HASHC; 79 /* FALLTHROUGH */ 80 case 5: 81 HASHC; 82 /* FALLTHROUGH */ 83 case 4: 84 HASHC; 85 /* FALLTHROUGH */ 86 case 3: 87 HASHC; 88 /* FALLTHROUGH */ 89 case 2: 90 HASHC; 91 /* FALLTHROUGH */ 92 case 1: 93 HASHC; 94 } while (--loop); 95 } 96 } 97 return (h); 98 } 99 100 /* 101 * Generate a hash value for a given key (character string). 102 * We mask off all but the lower 8 bits since our table array 103 * can only hold 256 elements. 104 */ 105 u_int32_t 106 hashkey(char *key) 107 { 108 109 if (key == NULL) 110 return (-1); 111 return(hash((void *)key, strlen(key)) & HASH_MASK); 112 } 113 114 /* Find an entry in the hash table (may be hanging off a linked list). */ 115 char * 116 lookup(struct group_entry *table[], char *key) 117 { 118 struct group_entry *cur; 119 120 cur = table[hashkey(key)]; 121 122 while (cur) { 123 if (!strcmp(cur->key, key)) 124 return(cur->data); 125 cur = cur->next; 126 } 127 128 return(NULL); 129 } 130 131 /* 132 * Store an entry in the main netgroup hash table. Here's how this 133 * works: the table can only be so big when we initialize it (TABLESIZE) 134 * but the number of netgroups in the /etc/netgroup file could easily be 135 * much larger than the table. Since our hash values are adjusted to 136 * never be greater than TABLESIZE too, this means it won't be long before 137 * we find ourselves with two keys that hash to the same value. 138 * 139 * One way to deal with this is to malloc(2) a second table and start 140 * doing indirection, but this is a pain in the butt and it's not worth 141 * going to all that trouble for a dinky little program like this. Instead, 142 * we turn each table entry into a linked list and simply link keys 143 * with the same hash value together at the same index location within 144 * the table. 145 * 146 * That's a lot of comment for such a small piece of code, isn't it. 147 */ 148 void 149 store(struct group_entry *table[], char *key, char *data) 150 { 151 struct group_entry *new; 152 u_int32_t i; 153 154 i = hashkey(key); 155 156 new = (struct group_entry *)malloc(sizeof(struct group_entry)); 157 new->key = strdup(key); 158 new->data = strdup(data); 159 new->next = table[i]; 160 table[i] = new; 161 162 return; 163 } 164 165 /* 166 * Store a group member entry and/or update its grouplist. This is 167 * a bit more complicated than the previous function since we have to 168 * maintain not only the hash table of group members, each group member 169 * structure also has a linked list of groups hung off it. If handed 170 * a member name that we haven't encountered before, we have to do 171 * two things: add that member to the table (possibly hanging them 172 * off the end of a linked list, as above), and add a group name to 173 * the member's grouplist list. If we're handed a name that already has 174 * an entry in the table, then we just have to do one thing, which is 175 * to update its grouplist. 176 */ 177 void 178 mstore(struct member_entry *table[], char *key, char *data, char *domain) 179 { 180 struct member_entry *cur, *new; 181 struct grouplist *tmp; 182 u_int32_t i; 183 184 i = hashkey(key); 185 cur = table[i]; 186 187 tmp = (struct grouplist *)malloc(sizeof(struct grouplist)); 188 tmp->groupname = strdup(data); 189 tmp->next = NULL; 190 191 /* Check if all we have to do is insert a new groupname. */ 192 while (cur) { 193 if (!strcmp(cur->key, key)) { 194 tmp->next = cur->groups; 195 cur->groups = tmp; 196 return; 197 } 198 cur = cur->next; 199 } 200 201 /* Didn't find a match -- add the whole mess to the table. */ 202 new = (struct member_entry *)malloc(sizeof(struct member_entry)); 203 new->key = strdup(key); 204 new->domain = domain ? strdup(domain) : "*"; 205 new->groups = tmp; 206 new->next = table[i]; 207 table[i] = new; 208 209 return; 210 } 211