yp_dblookup.c revision 95658 
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
33#ifndef lint
34static const char rcsid[] =
35  "$FreeBSD: head/usr.sbin/ypserv/yp_dblookup.c 95658 2002-04-28 15:18:50Z des $";
36#endif /* not lint */
37
38#include <db.h>
39#include <errno.h>
40#include <fcntl.h>
41#include <limits.h>
42#include <paths.h>
43#include <stdio.h>
44#include <stdlib.h>
45#include <string.h>
46#include <unistd.h>
47#include <sys/stat.h>
48#include <sys/param.h>
49#include <rpcsvc/yp.h>
50#include "yp_extern.h"
51
52int ypdb_debug = 0;
53enum ypstat yp_errno = YP_TRUE;
54
55#define PERM_SECURE (S_IRUSR|S_IWUSR)
56HASHINFO openinfo = {
57	4096,		/* bsize */
58	32,		/* ffactor */
59	256,		/* nelem */
60	2048 * 512, 	/* cachesize */
61	NULL,		/* hash */
62	0,		/* lorder */
63};
64
65#ifdef DB_CACHE
66#include <sys/queue.h>
67
68#ifndef MAXDBS
69#define MAXDBS 20
70#endif
71
72static int numdbs = 0;
73
74struct dbent {
75	DB *dbp;
76	char *name;
77	char *key;
78	int size;
79	int flags;
80};
81
82static TAILQ_HEAD(circlehead, circleq_entry) qhead;
83
84struct circleq_entry {
85	struct dbent *dbptr;
86	TAILQ_ENTRY(circleq_entry) links;
87};
88
89/*
90 * Initialize the circular queue.
91 */
92void
93yp_init_dbs(void)
94{
95	TAILQ_INIT(&qhead);
96	return;
97}
98
99/*
100 * Dynamically allocate an entry for the circular queue.
101 * Return a NULL pointer on failure.
102 */
103static struct circleq_entry *
104yp_malloc_qent(void)
105{
106	register struct circleq_entry *q;
107
108	q = (struct circleq_entry *)malloc(sizeof(struct circleq_entry));
109	if (q == NULL) {
110		yp_error("failed to malloc() circleq entry");
111		return(NULL);
112	}
113	bzero((char *)q, sizeof(struct circleq_entry));
114	q->dbptr = (struct dbent *)malloc(sizeof(struct dbent));
115	if (q->dbptr == NULL) {
116		yp_error("failed to malloc() circleq entry");
117		free(q);
118		return(NULL);
119	}
120	bzero((char *)q->dbptr, sizeof(struct dbent));
121
122	return(q);
123}
124
125/*
126 * Free a previously allocated circular queue
127 * entry.
128 */
129static void
130yp_free_qent(struct circleq_entry *q)
131{
132	/*
133	 * First, close the database. In theory, this is also
134	 * supposed to free the resources allocated by the DB
135	 * package, including the memory pointed to by q->dbptr->key.
136	 * This means we don't have to free q->dbptr->key here.
137	 */
138	if (q->dbptr->dbp) {
139		(void)(q->dbptr->dbp->close)(q->dbptr->dbp);
140		q->dbptr->dbp = NULL;
141	}
142	/*
143	 * Then free the database name, which was strdup()'ed.
144	 */
145	free(q->dbptr->name);
146
147	/*
148	 * Free the rest of the dbent struct.
149	 */
150	free(q->dbptr);
151	q->dbptr = NULL;
152
153	/*
154	 * Free the circleq struct.
155	 */
156	free(q);
157	q = NULL;
158
159	return;
160}
161
162/*
163 * Zorch a single entry in the dbent queue and release
164 * all its resources. (This always removes the last entry
165 * in the queue.)
166 */
167static void
168yp_flush(void)
169{
170	register struct circleq_entry *qptr;
171
172	qptr = TAILQ_LAST(&qhead, circlehead);
173	TAILQ_REMOVE(&qhead, qptr, links);
174	yp_free_qent(qptr);
175	numdbs--;
176
177	return;
178}
179
180/*
181 * Close all databases, erase all database names and empty the queue.
182 */
183void
184yp_flush_all(void)
185{
186	register struct circleq_entry *qptr;
187
188	while (!TAILQ_EMPTY(&qhead)) {
189		qptr = TAILQ_FIRST(&qhead); /* save this */
190		TAILQ_REMOVE(&qhead, qptr, links);
191		yp_free_qent(qptr);
192	}
193	numdbs = 0;
194
195	return;
196}
197
198static char *inter_string = "YP_INTERDOMAIN";
199static char *secure_string = "YP_SECURE";
200static int inter_sz = sizeof("YP_INTERDOMAIN") - 1;
201static int secure_sz = sizeof("YP_SECURE") - 1;
202
203static int
204yp_setflags(DB *dbp)
205{
206	DBT key = { NULL, 0 }, data = { NULL, 0 };
207	int flags = 0;
208
209	key.data = inter_string;
210	key.size = inter_sz;
211
212	if (!(dbp->get)(dbp, &key, &data, 0))
213		flags |= YP_INTERDOMAIN;
214
215	key.data = secure_string;
216	key.size = secure_sz;
217
218	if (!(dbp->get)(dbp, &key, &data, 0))
219		flags |= YP_SECURE;
220
221	return(flags);
222}
223
224int
225yp_testflag(char *map, char *domain, int flag)
226{
227	char buf[MAXPATHLEN + 2];
228	register struct circleq_entry *qptr;
229
230	if (map == NULL || domain == NULL)
231		return(0);
232
233	strcpy(buf, domain);
234	strcat(buf, "/");
235	strcat(buf, map);
236
237	TAILQ_FOREACH(qptr, &qhead, links) {
238		if (!strcmp(qptr->dbptr->name, buf)) {
239			if (qptr->dbptr->flags & flag)
240				return(1);
241			else
242				return(0);
243		}
244	}
245
246	if (yp_open_db_cache(domain, map, NULL, 0) == NULL)
247		return(0);
248
249	if (TAILQ_FIRST(&qhead)->dbptr->flags & flag)
250		return(1);
251
252	return(0);
253}
254
255/*
256 * Add a DB handle and database name to the cache. We only maintain
257 * fixed number of entries in the cache, so if we're asked to store
258 * a new entry when all our slots are already filled, we have to kick
259 * out the entry in the last slot to make room.
260 */
261static int
262yp_cache_db(DB *dbp, char *name, int size)
263{
264	register struct circleq_entry *qptr;
265
266	if (numdbs == MAXDBS) {
267		if (ypdb_debug)
268			yp_error("queue overflow -- releasing last slot");
269		yp_flush();
270	}
271
272	/*
273	 * Allocate a new queue entry.
274	 */
275
276	if ((qptr = yp_malloc_qent()) == NULL) {
277		yp_error("failed to allocate a new cache entry");
278		return(1);
279	}
280
281	qptr->dbptr->dbp = dbp;
282	qptr->dbptr->name = strdup(name);
283	qptr->dbptr->size = size;
284	qptr->dbptr->key = NULL;
285
286	qptr->dbptr->flags = yp_setflags(dbp);
287
288	TAILQ_INSERT_HEAD(&qhead, qptr, links);
289	numdbs++;
290
291	return(0);
292}
293
294/*
295 * Search the list for a database matching 'name.' If we find it,
296 * move it to the head of the list and return its DB handle. If
297 * not, just fail: yp_open_db_cache() will subsequently try to open
298 * the database itself and call yp_cache_db() to add it to the
299 * list.
300 *
301 * The search works like this:
302 *
303 * - The caller specifies the name of a database to locate. We try to
304 *   find an entry in our queue with a matching name.
305 *
306 * - If the caller doesn't specify a key or size, we assume that the
307 *   first entry that we encounter with a matching name is returned.
308 *   This will result in matches regardless of the key/size values
309 *   stored in the queue entry.
310 *
311 * - If the caller also specifies a key and length, we check to see
312 *   if the key and length saved in the queue entry also matches.
313 *   This lets us return a DB handle that's already positioned at the
314 *   correct location within a database.
315 *
316 * - Once we have a match, it gets migrated to the top of the queue
317 *   so that it will be easier to find if another request for
318 *   the same database comes in later.
319 */
320static DB *
321yp_find_db(const char *name, const char *key, int size)
322{
323	register struct circleq_entry *qptr;
324
325	TAILQ_FOREACH(qptr, &qhead, links) {
326		if (!strcmp(qptr->dbptr->name, name)) {
327			if (size) {
328				if (size != qptr->dbptr->size ||
329				   strncmp(qptr->dbptr->key, key, size))
330					continue;
331			} else {
332				if (qptr->dbptr->size)
333					continue;
334			}
335			if (qptr != TAILQ_FIRST(&qhead)) {
336				TAILQ_REMOVE(&qhead, qptr, links);
337				TAILQ_INSERT_HEAD(&qhead, qptr, links);
338			}
339			return(qptr->dbptr->dbp);
340		}
341	}
342
343	return(NULL);
344}
345
346/*
347 * Open a DB database and cache the handle for later use. We first
348 * check the cache to see if the required database is already open.
349 * If so, we fetch the handle from the cache. If not, we try to open
350 * the database and save the handle in the cache for later use.
351 */
352DB *
353yp_open_db_cache(const char *domain, const char *map, const char *key,
354    const int size)
355{
356	DB *dbp = NULL;
357	char buf[MAXPATHLEN + 2];
358/*
359	snprintf(buf, sizeof(buf), "%s/%s", domain, map);
360*/
361	yp_errno = YP_TRUE;
362
363	strcpy(buf, domain);
364	strcat(buf, "/");
365	strcat(buf, map);
366
367	if ((dbp = yp_find_db(buf, key, size)) != NULL) {
368		return(dbp);
369	} else {
370		if ((dbp = yp_open_db(domain, map)) != NULL) {
371			if (yp_cache_db(dbp, buf, size)) {
372				(void)(dbp->close)(dbp);
373				yp_errno = YP_YPERR;
374				return(NULL);
375			}
376		}
377	}
378
379	return (dbp);
380}
381#endif
382
383/*
384 * Open a DB database.
385 */
386DB *
387yp_open_db(const char *domain, const char *map)
388{
389	DB *dbp = NULL;
390	char buf[MAXPATHLEN + 2];
391
392	yp_errno = YP_TRUE;
393
394	if (map[0] == '.' || strchr(map, '/')) {
395		yp_errno = YP_BADARGS;
396		return (NULL);
397	}
398
399#ifdef DB_CACHE
400	if (yp_validdomain(domain)) {
401		yp_errno = YP_NODOM;
402		return(NULL);
403	}
404#endif
405	snprintf(buf, sizeof(buf), "%s/%s/%s", yp_dir, domain, map);
406
407#ifdef DB_CACHE
408again:
409#endif
410	dbp = dbopen(buf,O_RDONLY, PERM_SECURE, DB_HASH, NULL);
411
412	if (dbp == NULL) {
413		switch (errno) {
414#ifdef DB_CACHE
415		case ENFILE:
416			/*
417			 * We ran out of file descriptors. Nuke an
418			 * open one and try again.
419			 */
420			yp_error("ran out of file descriptors");
421			yp_flush();
422			goto again;
423			break;
424#endif
425		case ENOENT:
426			yp_errno = YP_NOMAP;
427			break;
428		case EFTYPE:
429			yp_errno = YP_BADDB;
430			break;
431		default:
432			yp_errno = YP_YPERR;
433			break;
434		}
435	}
436
437	return (dbp);
438}
439
440/*
441 * Database access routines.
442 *
443 * - yp_get_record(): retrieve an arbitrary key/data pair given one key
444 *                 to match against.
445 *
446 * - yp_first_record(): retrieve first key/data base in a database.
447 *
448 * - yp_next_record(): retrieve key/data pair that sequentially follows
449 *                   the supplied key value in the database.
450 */
451
452#ifdef DB_CACHE
453int
454yp_get_record(DB *dbp, const DBT *key, DBT *data, int allow)
455#else
456int
457yp_get_record(const char *domain, const char *map,
458    const DBT *key, DBT *data, int allow)
459#endif
460{
461#ifndef DB_CACHE
462	DB *dbp;
463#endif
464	int rval = 0;
465#ifndef DB_CACHE
466	static unsigned char buf[YPMAXRECORD];
467#endif
468
469	if (ypdb_debug)
470		yp_error("looking up key [%.*s]",
471			  key->size, key->data);
472
473	/*
474	 * Avoid passing back magic "YP_*" entries unless
475	 * the caller specifically requested them by setting
476	 * the 'allow' flag.
477	 */
478	if (!allow && !strncmp(key->data, "YP_", 3))
479		return(YP_NOKEY);
480
481#ifndef DB_CACHE
482	if ((dbp = yp_open_db(domain, map)) == NULL) {
483		return(yp_errno);
484	}
485#endif
486
487	if ((rval = (dbp->get)(dbp, key, data, 0)) != 0) {
488#ifdef DB_CACHE
489		TAILQ_FIRST(&qhead)->dbptr->size = 0;
490#else
491		(void)(dbp->close)(dbp);
492#endif
493		if (rval == 1)
494			return(YP_NOKEY);
495		else
496			return(YP_BADDB);
497	}
498
499	if (ypdb_debug)
500		yp_error("result of lookup: key: [%.*s] data: [%.*s]",
501			 key->size, key->data, data->size, data->data);
502
503#ifdef DB_CACHE
504	if (TAILQ_FIRST(&qhead)->dbptr->size) {
505		TAILQ_FIRST(&qhead)->dbptr->key = "";
506		TAILQ_FIRST(&qhead)->dbptr->size = 0;
507	}
508#else
509	bcopy(data->data, &buf, data->size);
510	data->data = &buf;
511	(void)(dbp->close)(dbp);
512#endif
513
514	return(YP_TRUE);
515}
516
517int
518yp_first_record(const DB *dbp, DBT *key, DBT *data, int allow)
519{
520	int rval;
521#ifndef DB_CACHE
522	static unsigned char buf[YPMAXRECORD];
523#endif
524
525	if (ypdb_debug)
526		yp_error("retrieving first key in map");
527
528	if ((rval = (dbp->seq)(dbp,key,data,R_FIRST)) != 0) {
529#ifdef DB_CACHE
530		TAILQ_FIRST(&qhead)->dbptr->size = 0;
531#endif
532		if (rval == 1)
533			return(YP_NOKEY);
534		else
535			return(YP_BADDB);
536	}
537
538	/* Avoid passing back magic "YP_*" records. */
539	while (!strncmp(key->data, "YP_", 3) && !allow) {
540		if ((rval = (dbp->seq)(dbp,key,data,R_NEXT)) != 0) {
541#ifdef DB_CACHE
542			TAILQ_FIRST(&qhead)->dbptr->size = 0;
543#endif
544			if (rval == 1)
545				return(YP_NOKEY);
546			else
547				return(YP_BADDB);
548		}
549	}
550
551	if (ypdb_debug)
552		yp_error("result of lookup: key: [%.*s] data: [%.*s]",
553			 key->size, key->data, data->size, data->data);
554
555#ifdef DB_CACHE
556	if (TAILQ_FIRST(&qhead)->dbptr->size) {
557		TAILQ_FIRST(&qhead)->dbptr->key = key->data;
558		TAILQ_FIRST(&qhead)->dbptr->size = key->size;
559	}
560#else
561	bcopy(data->data, &buf, data->size);
562	data->data = &buf;
563#endif
564
565	return(YP_TRUE);
566}
567
568int
569yp_next_record(const DB *dbp, DBT *key, DBT *data, int all, int allow)
570{
571	static DBT lkey = { NULL, 0 };
572	static DBT ldata = { NULL, 0 };
573	int rval;
574#ifndef DB_CACHE
575	static unsigned char keybuf[YPMAXRECORD];
576	static unsigned char datbuf[YPMAXRECORD];
577#endif
578
579	if (key == NULL || !key->size || key->data == NULL) {
580		rval = yp_first_record(dbp,key,data,allow);
581		if (rval == YP_NOKEY)
582			return(YP_NOMORE);
583		else {
584#ifdef DB_CACHE
585			TAILQ_FIRST(&qhead)->dbptr->key = key->data;
586			TAILQ_FIRST(&qhead)->dbptr->size = key->size;
587#endif
588			return(rval);
589		}
590	}
591
592	if (ypdb_debug)
593		yp_error("retrieving next key, previous was: [%.*s]",
594			  key->size, key->data);
595
596	if (!all) {
597#ifdef DB_CACHE
598		if (TAILQ_FIRST(&qhead)->dbptr->key == NULL) {
599#endif
600			(dbp->seq)(dbp,&lkey,&ldata,R_FIRST);
601			while (key->size != lkey.size ||
602			    strncmp(key->data, lkey.data,
603			    (int)key->size))
604				if ((dbp->seq)(dbp,&lkey,&ldata,R_NEXT)) {
605#ifdef DB_CACHE
606					TAILQ_FIRST(&qhead)->dbptr->size = 0;
607#endif
608					return(YP_NOKEY);
609				}
610
611#ifdef DB_CACHE
612		}
613#endif
614	}
615
616	if ((dbp->seq)(dbp,key,data,R_NEXT)) {
617#ifdef DB_CACHE
618		TAILQ_FIRST(&qhead)->dbptr->size = 0;
619#endif
620		return(YP_NOMORE);
621	}
622
623	/* Avoid passing back magic "YP_*" records. */
624	while (!strncmp(key->data, "YP_", 3) && !allow)
625		if ((dbp->seq)(dbp,key,data,R_NEXT)) {
626#ifdef DB_CACHE
627		TAILQ_FIRST(&qhead)->dbptr->size = 0;
628#endif
629			return(YP_NOMORE);
630		}
631
632	if (ypdb_debug)
633		yp_error("result of lookup: key: [%.*s] data: [%.*s]",
634			 key->size, key->data, data->size, data->data);
635
636#ifdef DB_CACHE
637	if (TAILQ_FIRST(&qhead)->dbptr->size) {
638		TAILQ_FIRST(&qhead)->dbptr->key = key->data;
639		TAILQ_FIRST(&qhead)->dbptr->size = key->size;
640	}
641#else
642	bcopy(key->data, &keybuf, key->size);
643	lkey.data = &keybuf;
644	lkey.size = key->size;
645	bcopy(data->data, &datbuf, data->size);
646	data->data = &datbuf;
647#endif
648
649	return(YP_TRUE);
650}
651
652#ifdef DB_CACHE
653/*
654 * Database glue functions.
655 */
656
657static DB *yp_currmap_db = NULL;
658static int yp_allow_db = 0;
659
660ypstat
661yp_select_map(char *map, char *domain, keydat *key, int allow)
662{
663	if (key == NULL)
664		yp_currmap_db = yp_open_db_cache(domain, map, NULL, 0);
665	else
666		yp_currmap_db = yp_open_db_cache(domain, map,
667						 key->keydat_val,
668						 key->keydat_len);
669
670	yp_allow_db = allow;
671	return(yp_errno);
672}
673
674ypstat
675yp_getbykey(keydat *key, valdat *val)
676{
677	DBT db_key = { NULL, 0 }, db_val = { NULL, 0 };
678	ypstat rval;
679
680	db_key.data = key->keydat_val;
681	db_key.size = key->keydat_len;
682
683	rval = yp_get_record(yp_currmap_db,
684				&db_key, &db_val, yp_allow_db);
685
686	if (rval == YP_TRUE) {
687		val->valdat_val = db_val.data;
688		val->valdat_len = db_val.size;
689	}
690
691	return(rval);
692}
693
694ypstat
695yp_firstbykey(keydat *key, valdat *val)
696{
697	DBT db_key = { NULL, 0 }, db_val = { NULL, 0 };
698	ypstat rval;
699
700	rval = yp_first_record(yp_currmap_db, &db_key, &db_val, yp_allow_db);
701
702	if (rval == YP_TRUE) {
703		key->keydat_val = db_key.data;
704		key->keydat_len = db_key.size;
705		val->valdat_val = db_val.data;
706		val->valdat_len = db_val.size;
707	}
708
709	return(rval);
710}
711
712ypstat
713yp_nextbykey(keydat *key, valdat *val)
714{
715	DBT db_key = { NULL, 0 }, db_val = { NULL, 0 };
716	ypstat rval;
717
718	db_key.data = key->keydat_val;
719	db_key.size = key->keydat_len;
720
721	rval = yp_next_record(yp_currmap_db, &db_key, &db_val, 0, yp_allow_db);
722
723	if (rval == YP_TRUE) {
724		key->keydat_val = db_key.data;
725		key->keydat_len = db_key.size;
726		val->valdat_val = db_val.data;
727		val->valdat_len = db_val.size;
728	}
729
730	return(rval);
731}
732#endif
733