1 |
/* |
2 |
* Boa, an http server |
3 |
* Copyright (C) 1995 Paul Phillips <paulp@go2net.com> |
4 |
* Some changes Copyright (C) 1996 Larry Doolittle <ldoolitt@boa.org> |
5 |
* Some changes Copyright (C) 1997 Jon Nelson <jnelson@boa.org> |
6 |
* |
7 |
* This program is free software; you can redistribute it and/or modify |
8 |
* it under the terms of the GNU General Public License as published by |
9 |
* the Free Software Foundation; either version 1, or (at your option) |
10 |
* any later version. |
11 |
* |
12 |
* This program is distributed in the hope that it will be useful, |
13 |
* but WITHOUT ANY WARRANTY; without even the implied warranty of |
14 |
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
15 |
* GNU General Public License for more details. |
16 |
* |
17 |
* You should have received a copy of the GNU General Public License |
18 |
* along with this program; if not, write to the Free Software |
19 |
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
20 |
* |
21 |
*/ |
22 |
|
23 |
/* $Id: hash.c,v 1.14.4.7 2002/09/23 03:44:08 jnelson Exp $*/ |
24 |
|
25 |
#include "boa.h" |
26 |
#include "parse.h" |
27 |
|
28 |
#define DEBUG if |
29 |
#define DEBUG_HASH 0 |
30 |
|
31 |
/* |
32 |
* There are two hash tables used, each with a key/value pair |
33 |
* stored in a hash_struct. They are: |
34 |
* |
35 |
* mime_hashtable: |
36 |
* key = file extension |
37 |
* value = mime type |
38 |
* |
39 |
* passwd_hashtable: |
40 |
* key = username |
41 |
* value = home directory |
42 |
* |
43 |
*/ |
44 |
|
45 |
struct _hash_struct_ { |
46 |
char *key; |
47 |
char *value; |
48 |
struct _hash_struct_ *next; |
49 |
}; |
50 |
|
51 |
typedef struct _hash_struct_ hash_struct; |
52 |
|
53 |
static hash_struct *mime_hashtable[MIME_HASHTABLE_SIZE]; |
54 |
static hash_struct *passwd_hashtable[PASSWD_HASHTABLE_SIZE]; |
55 |
|
56 |
#ifdef WANT_ICKY_HASH |
57 |
static unsigned four_char_hash(const char *buf); |
58 |
#define boa_hash four_char_hash |
59 |
#else |
60 |
#ifdef WANT_SDBM_HASH |
61 |
static unsigned sdbm_hash(const char *str); |
62 |
#define boa_hash sdbm_hash |
63 |
#else |
64 |
#ifdef WANT_DJB2_HASH |
65 |
static unsigned djb2_hash(const char *str); |
66 |
#define boa_hash djb2_hash |
67 |
#else |
68 |
static unsigned fnv1a_hash(const char *str); |
69 |
#define boa_hash fnv1a_hash |
70 |
#endif |
71 |
#endif |
72 |
#endif |
73 |
|
74 |
#ifdef WANT_ICKY_HASH |
75 |
static unsigned four_char_hash(const char *buf) |
76 |
{ |
77 |
unsigned int hash = (buf[0] + |
78 |
(buf[1] ? buf[1] : 241 + |
79 |
(buf[2] ? buf[2] : 251 + |
80 |
(buf[3] ? buf[3] : 257)))); |
81 |
DEBUG(DEBUG_HASH) { |
82 |
log_error_time(); |
83 |
fprintf(stderr, "four_char_hash(%s) = %u\n", buf, hash); |
84 |
} |
85 |
return hash; |
86 |
} |
87 |
|
88 |
/* The next two hashes taken from |
89 |
* http://www.cs.yorku.ca/~oz/hash.html |
90 |
* |
91 |
* In my (admittedly) very brief testing, djb2_hash performed |
92 |
* very slightly better than sdbm_hash. |
93 |
*/ |
94 |
|
95 |
#else |
96 |
#define MAX_HASH_LENGTH 4 |
97 |
#ifdef WANT_SDBM_HASH |
98 |
static unsigned sdbm_hash(const char *str) |
99 |
{ |
100 |
unsigned hash = 0; |
101 |
int c; |
102 |
short count = MAX_HASH_LENGTH; |
103 |
|
104 |
DEBUG(DEBUG_HASH) { |
105 |
log_error_time(); |
106 |
fprintf(stderr, "sdbm_hash(%s) = ", str); |
107 |
} |
108 |
|
109 |
while ((c = *str++) && count--) |
110 |
hash = c + (hash << 6) + (hash << 16) - hash; |
111 |
|
112 |
DEBUG(DEBUG_HASH) { |
113 |
fprintf(stderr, "%u\n", hash); |
114 |
} |
115 |
return hash; |
116 |
} |
117 |
#else |
118 |
#ifdef WANT_DJB2_HASH |
119 |
static unsigned djb2_hash(const char *str) |
120 |
{ |
121 |
unsigned hash = 5381; |
122 |
int c; |
123 |
short count = MAX_HASH_LENGTH; |
124 |
|
125 |
DEBUG(DEBUG_HASH) { |
126 |
log_error_time(); |
127 |
fprintf(stderr, "djb2_hash(%s) = ", str); |
128 |
} |
129 |
|
130 |
while ((c = *(str++)) && count--) |
131 |
hash = ((hash << 5) + hash) + c; /* hash * 33 + c */ |
132 |
|
133 |
DEBUG(DEBUG_HASH) { |
134 |
fprintf(stderr, "%u\n", hash); |
135 |
} |
136 |
return hash; |
137 |
} |
138 |
#else |
139 |
/* |
140 |
* magic 32 bit FNV1a hash constants |
141 |
* |
142 |
* See: http://www.isthe.com/chongo/tech/comp/fnv/index.html |
143 |
*/ |
144 |
#define OFFSET_BASIS 2166136261U |
145 |
#define FNV_PRIME 16777619U |
146 |
static unsigned fnv1a_hash(const char *str) |
147 |
{ |
148 |
unsigned int hash = OFFSET_BASIS; |
149 |
short count = MAX_HASH_LENGTH; |
150 |
|
151 |
/* |
152 |
* compute FNV1a hash of the first file component |
153 |
*/ |
154 |
do { |
155 |
hash ^= *str++; |
156 |
hash *= FNV_PRIME; |
157 |
} while (*str != '\0' && count--); |
158 |
|
159 |
return hash; |
160 |
} |
161 |
|
162 |
#endif |
163 |
#endif |
164 |
#endif |
165 |
|
166 |
/* |
167 |
* Name: hash_insert |
168 |
* Description: Adds a key/value pair to the provided hashtable |
169 |
*/ |
170 |
|
171 |
static |
172 |
hash_struct *hash_insert(hash_struct *table[], unsigned int hash, char *key, char *value) |
173 |
{ |
174 |
hash_struct *current, *trailer; |
175 |
|
176 |
if (!key) { |
177 |
log_error_time(); |
178 |
fprintf(stderr, "Yipes! Null value sent as key to hash_insert!\n"); |
179 |
return NULL; |
180 |
} |
181 |
|
182 |
/* should we bother to check table, hash, and key for NULL/0 ? */ |
183 |
|
184 |
DEBUG(DEBUG_HASH) |
185 |
fprintf(stderr, |
186 |
"Adding key \"%s\" for value \"%s\" (hash=%d)\n", |
187 |
key, value, hash); |
188 |
|
189 |
current = table[hash]; |
190 |
while (current) { |
191 |
if (!strcmp(current->key, key)) |
192 |
return current; /* don't add extension twice */ |
193 |
if (current->next) |
194 |
current = current->next; |
195 |
else |
196 |
break; |
197 |
} |
198 |
|
199 |
/* not found */ |
200 |
trailer = (hash_struct *) malloc(sizeof (hash_struct)); |
201 |
if (trailer == NULL) { |
202 |
WARN("unable to allocate memory for hash_insert"); |
203 |
return NULL; |
204 |
} |
205 |
|
206 |
trailer->key = strdup(key); |
207 |
trailer->value = strdup(value); |
208 |
trailer->next = NULL; |
209 |
|
210 |
if (trailer->key == NULL || trailer->value == NULL) { |
211 |
free(trailer); |
212 |
if (trailer->key) |
213 |
free(trailer->key); |
214 |
if (trailer->value) |
215 |
free(trailer->value); |
216 |
WARN("allocated key or value is NULL"); |
217 |
return NULL; |
218 |
} |
219 |
|
220 |
/* successfully allocated and built new hash structure */ |
221 |
if (!current) { |
222 |
/* no entries for this hash value */ |
223 |
table[hash] = trailer; |
224 |
} else { |
225 |
current->next = trailer; |
226 |
} |
227 |
|
228 |
return trailer; |
229 |
} |
230 |
|
231 |
static |
232 |
hash_struct *find_in_hash(hash_struct *table[], char *key, unsigned int hash) |
233 |
{ |
234 |
hash_struct *current; |
235 |
|
236 |
current = table[hash]; |
237 |
|
238 |
while (current) { |
239 |
if (!strcmp(current->key, key)) /* hit */ |
240 |
return current; |
241 |
current = current->next; |
242 |
} |
243 |
|
244 |
return NULL; |
245 |
} |
246 |
|
247 |
/* |
248 |
* Name: add_mime_type |
249 |
* Description: Adds a key/value pair to the mime_hashtable |
250 |
*/ |
251 |
|
252 |
void add_mime_type(char *extension, char *type) |
253 |
{ |
254 |
unsigned int hash; |
255 |
|
256 |
if (!extension || extension[0] == '\0') { |
257 |
log_error_time(); |
258 |
fprintf(stderr, "Yipes! Null value sent as key to add_mime_type!\n"); |
259 |
return; |
260 |
} |
261 |
|
262 |
hash = get_mime_hash_value(extension); |
263 |
hash_insert(mime_hashtable, hash, extension, type); |
264 |
} |
265 |
|
266 |
/* |
267 |
* Name: get_mime_hash_value |
268 |
* |
269 |
* Description: adds the ASCII values of the file extension letters |
270 |
* and mods by the hashtable size to get the hash value |
271 |
*/ |
272 |
|
273 |
unsigned get_mime_hash_value(char *extension) |
274 |
{ |
275 |
if (extension == NULL || extension[0] == '\0') { |
276 |
/* FIXME */ |
277 |
log_error_time(); |
278 |
fprintf(stderr, "Attempt to hash NULL or empty string! [get_mime_hash_value]!\n"); |
279 |
return 0; |
280 |
} |
281 |
|
282 |
return boa_hash(extension) % MIME_HASHTABLE_SIZE; |
283 |
} |
284 |
|
285 |
/* |
286 |
* Name: get_mime_type |
287 |
* |
288 |
* Description: Returns the mime type for a supplied filename. |
289 |
* Returns default type if not found. |
290 |
*/ |
291 |
|
292 |
char *get_mime_type(const char *filename) |
293 |
{ |
294 |
char *extension; |
295 |
hash_struct *current; |
296 |
|
297 |
unsigned int hash; |
298 |
|
299 |
extension = strrchr(filename, '.'); |
300 |
|
301 |
/* remember, extension points to the *last* '.' in the filename, |
302 |
* which may be NULL or look like: |
303 |
* foo.bar |
304 |
* foo. (in which case extension[1] == '\0') |
305 |
*/ |
306 |
if (!extension || extension[1] == '\0') |
307 |
return default_type; |
308 |
|
309 |
/* make sure we hash on the 'bar' not the '.bar' */ |
310 |
++extension; |
311 |
|
312 |
hash = get_mime_hash_value(extension); |
313 |
current = find_in_hash(mime_hashtable, extension, hash); |
314 |
return (current ? current->value : default_type); |
315 |
} |
316 |
|
317 |
/* |
318 |
* Name: get_homedir_hash_value |
319 |
* |
320 |
* Description: adds the ASCII values of the username letters |
321 |
* and mods by the hashtable size to get the hash value |
322 |
*/ |
323 |
|
324 |
unsigned get_homedir_hash_value(char *name) |
325 |
{ |
326 |
unsigned int hash = 0; |
327 |
|
328 |
if (name == NULL || name[0] == '\0') { |
329 |
/* FIXME */ |
330 |
log_error_time(); |
331 |
fprintf(stderr, "Attempt to hash NULL or empty string! [get_homedir_hash_value]\n"); |
332 |
return 0; |
333 |
} |
334 |
|
335 |
hash = boa_hash(name) % PASSWD_HASHTABLE_SIZE; |
336 |
|
337 |
return hash; |
338 |
} |
339 |
|
340 |
|
341 |
/* |
342 |
* Name: get_home_dir |
343 |
* |
344 |
* Description: Returns a point to the supplied user's home directory. |
345 |
* Adds to the hashtable if it's not already present. |
346 |
* |
347 |
*/ |
348 |
|
349 |
char *get_home_dir(char *name) |
350 |
{ |
351 |
hash_struct *current; |
352 |
|
353 |
unsigned int hash; |
354 |
|
355 |
hash = get_homedir_hash_value(name); |
356 |
|
357 |
current = find_in_hash(passwd_hashtable, name, hash); |
358 |
|
359 |
if (!current) { |
360 |
/* not found */ |
361 |
struct passwd *passwdbuf; |
362 |
|
363 |
passwdbuf = getpwnam(name); |
364 |
|
365 |
if (!passwdbuf) /* does not exist */ |
366 |
return NULL; |
367 |
|
368 |
current = hash_insert(passwd_hashtable, hash, name, passwdbuf->pw_dir); |
369 |
} |
370 |
|
371 |
return (current ? current->value : NULL); |
372 |
} |
373 |
|
374 |
static |
375 |
void clear_hashtable(hash_struct *table[], int size) |
376 |
{ |
377 |
int i; |
378 |
hash_struct *temp; |
379 |
for (i = 0; i < size; ++i) { /* these limits OK? */ |
380 |
temp = table[i]; |
381 |
while (temp) { |
382 |
hash_struct *temp_next; |
383 |
|
384 |
temp_next = temp->next; |
385 |
free(temp->key); |
386 |
free(temp->value); |
387 |
free(temp); |
388 |
|
389 |
temp = temp_next; |
390 |
} |
391 |
table[i] = NULL; |
392 |
} |
393 |
} |
394 |
|
395 |
void dump_mime(void) |
396 |
{ |
397 |
clear_hashtable(mime_hashtable, MIME_HASHTABLE_SIZE); |
398 |
} |
399 |
|
400 |
void dump_passwd(void) |
401 |
{ |
402 |
clear_hashtable(passwd_hashtable, PASSWD_HASHTABLE_SIZE); |
403 |
} |
404 |
|
405 |
void show_hash_stats(void) |
406 |
{ |
407 |
int i; |
408 |
hash_struct *temp; |
409 |
int total = 0; |
410 |
int count; |
411 |
|
412 |
log_error_time(); |
413 |
fprintf(stderr, "mmap_hashtable has %d entries\n", mmap_list_entries_used); |
414 |
|
415 |
for (i = 0; i < MIME_HASHTABLE_SIZE; ++i) { /* these limits OK? */ |
416 |
if (mime_hashtable[i]) { |
417 |
count = 0; |
418 |
temp = mime_hashtable[i]; |
419 |
while (temp) { |
420 |
temp = temp->next; |
421 |
++count; |
422 |
} |
423 |
#ifdef NOISY_SIGALRM |
424 |
log_error_time(); |
425 |
fprintf(stderr, "mime_hashtable[%d] has %d entries\n", |
426 |
i, count); |
427 |
#endif |
428 |
total += count; |
429 |
} |
430 |
} |
431 |
log_error_time(); |
432 |
fprintf(stderr, "mime_hashtable has %d total entries\n", total); |
433 |
|
434 |
total = 0; |
435 |
for (i = 0; i < PASSWD_HASHTABLE_SIZE; ++i) { /* these limits OK? */ |
436 |
if (passwd_hashtable[i]) { |
437 |
temp = passwd_hashtable[i]; |
438 |
count = 0; |
439 |
while (temp) { |
440 |
temp = temp->next; |
441 |
++count; |
442 |
} |
443 |
#ifdef NOISY_SIGALRM |
444 |
log_error_time(); |
445 |
fprintf(stderr, "passwd_hashtable[%d] has %d entries\n", |
446 |
i, count); |
447 |
#endif |
448 |
total += count; |
449 |
} |
450 |
} |
451 |
|
452 |
log_error_time(); |
453 |
fprintf(stderr, "passwd_hashtable has %d total entries\n", |
454 |
total); |
455 |
|
456 |
} |