source: vendor/FreeBSD-libc/current/net/nsdispatch.c

Last change on this file was 1695, checked in by bird, 21 years ago

FreeBSD 5.3 libc sources.
  • Property cvs2svn:cvs-rev set to 1.1.1.2
  • Property svn:eol-style set to native
  • Property svn:executable set to *
File size: 16.6 KB
Line 
1/* $NetBSD: nsdispatch.c,v 1.9 1999/01/25 00:16:17 lukem Exp $ */
2
3/*-
4 * Copyright (c) 1997, 1998, 1999 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Luke Mewburn.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the NetBSD
21 * Foundation, Inc. and its contributors.
22 * 4. Neither the name of The NetBSD Foundation nor the names of its
23 * contributors may be used to endorse or promote products derived
24 * from this software without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36 * POSSIBILITY OF SUCH DAMAGE.
37 */
38/*-
39 * Copyright (c) 2003 Networks Associates Technology, Inc.
40 * All rights reserved.
41 *
42 * Portions of this software were developed for the FreeBSD Project by
43 * Jacques A. Vidrine, Safeport Network Services, and Network
44 * Associates Laboratories, the Security Research Division of Network
45 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035
46 * ("CBOSS"), as part of the DARPA CHATS research program.
47 *
48 * Redistribution and use in source and binary forms, with or without
49 * modification, are permitted provided that the following conditions
50 * are met:
51 * 1. Redistributions of source code must retain the above copyright
52 * notice, this list of conditions and the following disclaimer.
53 * 2. Redistributions in binary form must reproduce the above copyright
54 * notice, this list of conditions and the following disclaimer in the
55 * documentation and/or other materials provided with the distribution.
56 *
57 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
58 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
59 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
60 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
61 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
62 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
63 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
64 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
65 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
66 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
67 * SUCH DAMAGE.
68 *
69 */
70#include <sys/cdefs.h>
71__FBSDID("$FreeBSD: src/lib/libc/net/nsdispatch.c,v 1.12 2004/04/01 19:12:45 nectar Exp $");
72
73#include "namespace.h"
74#include <sys/param.h>
75#include <sys/stat.h>
76
77#include <dlfcn.h>
78#include <errno.h>
79#include <fcntl.h>
80#define _NS_PRIVATE
81#include <nsswitch.h>
82#include <pthread.h>
83#include <stdio.h>
84#include <stdlib.h>
85#include <string.h>
86#include <syslog.h>
87#include <unistd.h>
88#include "un-namespace.h"
89
90enum _nss_constants {
91 /* Number of elements allocated when we grow a vector */
92 ELEMSPERCHUNK = 8
93};
94
95/*
96 * Global NSS data structures are mostly read-only, but we update
97 * them when we read or re-read the nsswitch.conf.
98 */
99static pthread_rwlock_t nss_lock = PTHREAD_RWLOCK_INITIALIZER;
100
101/*
102 * Runtime determination of whether we are dynamically linked or not.
103 */
104extern int _DYNAMIC __attribute__ ((weak));
105#define is_dynamic() (&_DYNAMIC != NULL)
106
107/*
108 * default sourcelist: `files'
109 */
110const ns_src __nsdefaultsrc[] = {
111 { NSSRC_FILES, NS_SUCCESS },
112 { 0 },
113};
114
115/* Database, source mappings. */
116static unsigned int _nsmapsize;
117static ns_dbt *_nsmap = NULL;
118
119/* NSS modules. */
120static unsigned int _nsmodsize;
121static ns_mod *_nsmod;
122
123/* Placeholder for builtin modules' dlopen `handle'. */
124static int __nss_builtin_handle;
125static void *nss_builtin_handle = &__nss_builtin_handle;
126
127/*
128 * Attempt to spew relatively uniform messages to syslog.
129 */
130#define nss_log(level, fmt, ...) \
131 syslog((level), "NSSWITCH(%s): " fmt, __func__, __VA_ARGS__)
132#define nss_log_simple(level, s) \
133 syslog((level), "NSSWITCH(%s): " s, __func__)
134
135/*
136 * Dynamically growable arrays are used for lists of databases, sources,
137 * and modules. The following `vector' interface is used to isolate the
138 * common operations.
139 */
140typedef int (*vector_comparison)(const void *, const void *);
141typedef void (*vector_free_elem)(void *);
142static void vector_sort(void *, unsigned int, size_t,
143 vector_comparison);
144static void vector_free(void *, unsigned int *, size_t,
145 vector_free_elem);
146static void *vector_ref(unsigned int, void *, unsigned int, size_t);
147static void *vector_search(const void *, void *, unsigned int, size_t,
148 vector_comparison);
149static void *vector_append(const void *, void *, unsigned int *, size_t);
150
151
152/*
153 * Internal interfaces.
154 */
155static int string_compare(const void *, const void *);
156static int mtab_compare(const void *, const void *);
157static int nss_configure(void);
158static void ns_dbt_free(ns_dbt *);
159static void ns_mod_free(ns_mod *);
160static void ns_src_free(ns_src **, int);
161static void nss_load_builtin_modules(void);
162static void nss_load_module(const char *, nss_module_register_fn);
163static void nss_atexit(void);
164/* nsparser */
165extern FILE *_nsyyin;
166
167
168/*
169 * The vector operations
170 */
171static void
172vector_sort(void *vec, unsigned int count, size_t esize,
173 vector_comparison comparison)
174{
175 qsort(vec, count, esize, comparison);
176}
177
178
179static void *
180vector_search(const void *key, void *vec, unsigned int count, size_t esize,
181 vector_comparison comparison)
182{
183 return (bsearch(key, vec, count, esize, comparison));
184}
185
186
187static void *
188vector_append(const void *elem, void *vec, unsigned int *count, size_t esize)
189{
190 void *p;
191
192 if ((*count % ELEMSPERCHUNK) == 0) {
193 p = realloc(vec, (*count + ELEMSPERCHUNK) * esize);
194 if (p == NULL) {
195 nss_log_simple(LOG_ERR, "memory allocation failure");
196 return (vec);
197 }
198 vec = p;
199 }
200 memmove((void *)(((uintptr_t)vec) + (*count * esize)), elem, esize);
201 (*count)++;
202 return (vec);
203}
204
205
206static void *
207vector_ref(unsigned int i, void *vec, unsigned int count, size_t esize)
208{
209 if (i < count)
210 return (void *)((uintptr_t)vec + (i * esize));
211 else
212 return (NULL);
213}
214
215
216#define VECTOR_FREE(v, c, s, f) \
217 do { vector_free(v, c, s, f); v = NULL; } while (0)
218static void
219vector_free(void *vec, unsigned int *count, size_t esize,
220 vector_free_elem free_elem)
221{
222 unsigned int i;
223 void *elem;
224
225 for (i = 0; i < *count; i++) {
226 elem = vector_ref(i, vec, *count, esize);
227 if (elem != NULL)
228 free_elem(elem);
229 }
230 free(vec);
231 *count = 0;
232}
233
234
235
236/*
237 * Comparison functions for vector_search.
238 */
239static int
240string_compare(const void *a, const void *b)
241{
242 return (strcasecmp(*(const char * const *)a, *(const char * const *)b));
243}
244
245
246static int
247mtab_compare(const void *a, const void *b)
248{
249 int cmp;
250
251 cmp = strcmp(((const ns_mtab *)a)->name, ((const ns_mtab *)b)->name);
252 if (cmp != 0)
253 return (cmp);
254 else
255 return (strcmp(((const ns_mtab *)a)->database,
256 ((const ns_mtab *)b)->database));
257}
258
259
260
261/*
262 * NSS nsmap management.
263 */
264void
265_nsdbtaddsrc(ns_dbt *dbt, const ns_src *src)
266{
267 const ns_mod *modp;
268
269 dbt->srclist = vector_append(src, dbt->srclist, &dbt->srclistsize,
270 sizeof(*src));
271 modp = vector_search(&src->name, _nsmod, _nsmodsize, sizeof(*_nsmod),
272 string_compare);
273 if (modp == NULL)
274 nss_load_module(src->name, NULL);
275}
276
277
278#ifdef _NSS_DEBUG
279void
280_nsdbtdump(const ns_dbt *dbt)
281{
282 int i;
283
284 printf("%s (%d source%s):", dbt->name, dbt->srclistsize,
285 dbt->srclistsize == 1 ? "" : "s");
286 for (i = 0; i < (int)dbt->srclistsize; i++) {
287 printf(" %s", dbt->srclist[i].name);
288 if (!(dbt->srclist[i].flags &
289 (NS_UNAVAIL|NS_NOTFOUND|NS_TRYAGAIN)) &&
290 (dbt->srclist[i].flags & NS_SUCCESS))
291 continue;
292 printf(" [");
293 if (!(dbt->srclist[i].flags & NS_SUCCESS))
294 printf(" SUCCESS=continue");
295 if (dbt->srclist[i].flags & NS_UNAVAIL)
296 printf(" UNAVAIL=return");
297 if (dbt->srclist[i].flags & NS_NOTFOUND)
298 printf(" NOTFOUND=return");
299 if (dbt->srclist[i].flags & NS_TRYAGAIN)
300 printf(" TRYAGAIN=return");
301 printf(" ]");
302 }
303 printf("\n");
304}
305#endif
306
307
308/*
309 * The first time nsdispatch is called (during a process's lifetime,
310 * or after nsswitch.conf has been updated), nss_configure will
311 * prepare global data needed by NSS.
312 */
313static int
314nss_configure(void)
315{
316 static pthread_mutex_t conf_lock = PTHREAD_MUTEX_INITIALIZER;
317 static time_t confmod;
318 struct stat statbuf;
319 int result, isthreaded;
320 const char *path;
321
322 result = 0;
323 isthreaded = __isthreaded;
324#if defined(_NSS_DEBUG) && defined(_NSS_SHOOT_FOOT)
325 /* NOTE WELL: THIS IS A SECURITY HOLE. This must only be built
326 * for debugging purposes and MUST NEVER be used in production.
327 */
328 path = getenv("NSSWITCH_CONF");
329 if (path == NULL)
330#endif
331 path = _PATH_NS_CONF;
332 if (stat(path, &statbuf) != 0)
333 return (0);
334 if (statbuf.st_mtime <= confmod)
335 return (0);
336 if (isthreaded) {
337 result = _pthread_mutex_trylock(&conf_lock);
338 if (result != 0)
339 return (0);
340 (void)_pthread_rwlock_unlock(&nss_lock);
341 result = _pthread_rwlock_wrlock(&nss_lock);
342 if (result != 0)
343 goto fin2;
344 }
345 _nsyyin = fopen(path, "r");
346 if (_nsyyin == NULL)
347 goto fin;
348 VECTOR_FREE(_nsmap, &_nsmapsize, sizeof(*_nsmap),
349 (vector_free_elem)ns_dbt_free);
350 VECTOR_FREE(_nsmod, &_nsmodsize, sizeof(*_nsmod),
351 (vector_free_elem)ns_mod_free);
352 nss_load_builtin_modules();
353 _nsyyparse();
354 (void)fclose(_nsyyin);
355 vector_sort(_nsmap, _nsmapsize, sizeof(*_nsmap), string_compare);
356 if (confmod == 0)
357 (void)atexit(nss_atexit);
358 confmod = statbuf.st_mtime;
359fin:
360 if (isthreaded) {
361 (void)_pthread_rwlock_unlock(&nss_lock);
362 if (result == 0)
363 result = _pthread_rwlock_rdlock(&nss_lock);
364 }
365fin2:
366 if (isthreaded)
367 (void)_pthread_mutex_unlock(&conf_lock);
368 return (result);
369}
370
371
372void
373_nsdbtput(const ns_dbt *dbt)
374{
375 unsigned int i;
376 ns_dbt *p;
377
378 for (i = 0; i < _nsmapsize; i++) {
379 p = vector_ref(i, _nsmap, _nsmapsize, sizeof(*_nsmap));
380 if (string_compare(&dbt->name, &p->name) == 0) {
381 /* overwrite existing entry */
382 if (p->srclist != NULL)
383 ns_src_free(&p->srclist, p->srclistsize);
384 memmove(p, dbt, sizeof(*dbt));
385 return;
386 }
387 }
388 _nsmap = vector_append(dbt, _nsmap, &_nsmapsize, sizeof(*_nsmap));
389}
390
391
392static void
393ns_dbt_free(ns_dbt *dbt)
394{
395 ns_src_free(&dbt->srclist, dbt->srclistsize);
396}
397
398
399static void
400ns_src_free(ns_src **src, int srclistsize)
401{
402 int i;
403
404 for (i = 0; i < srclistsize; i++)
405 if ((*src)[i].name != NULL)
406 /* This one was allocated by nslexer. You'll just
407 * have to trust me.
408 */
409 free((void *)((*src)[i].name));
410 free(*src);
411 *src = NULL;
412}
413
414
415
416/*
417 * NSS module management.
418 */
419/* The built-in NSS modules are all loaded at once. */
420#define NSS_BACKEND(name, reg) \
421ns_mtab *reg(unsigned int *, nss_module_unregister_fn *);
422#include "nss_backends.h"
423#undef NSS_BACKEND
424
425static void
426nss_load_builtin_modules(void)
427{
428#define NSS_BACKEND(name, reg) nss_load_module(#name, reg);
429#include "nss_backends.h"
430#undef NSS_BACKEND
431}
432
433
434/* Load a built-in or dynamically linked module. If the `reg_fn'
435 * argument is non-NULL, assume a built-in module and use reg_fn to
436 * register it. Otherwise, search for a dynamic NSS module.
437 */
438static void
439nss_load_module(const char *source, nss_module_register_fn reg_fn)
440{
441 char buf[PATH_MAX];
442 ns_mod mod;
443 nss_module_register_fn fn;
444
445 memset(&mod, 0, sizeof(mod));
446 mod.name = strdup(source);
447 if (mod.name == NULL) {
448 nss_log_simple(LOG_ERR, "memory allocation failure");
449 return;
450 }
451 if (reg_fn != NULL) {
452 /* The placeholder is required, as a NULL handle
453 * represents an invalid module.
454 */
455 mod.handle = nss_builtin_handle;
456 fn = reg_fn;
457 } else if (!is_dynamic())
458 goto fin;
459 else {
460 if (snprintf(buf, sizeof(buf), "nss_%s.so.%d", mod.name,
461 NSS_MODULE_INTERFACE_VERSION) >= (int)sizeof(buf))
462 goto fin;
463 mod.handle = dlopen(buf, RTLD_LOCAL|RTLD_LAZY);
464 if (mod.handle == NULL) {
465#ifdef _NSS_DEBUG
466 /* This gets pretty annoying since the built-in
467 * sources aren't modules yet.
468 */
469 nss_log(LOG_DEBUG, "%s, %s", mod.name, dlerror());
470#endif
471 goto fin;
472 }
473 fn = (nss_module_register_fn)dlfunc(mod.handle,
474 "nss_module_register");
475 if (fn == NULL) {
476 (void)dlclose(mod.handle);
477 mod.handle = NULL;
478 nss_log(LOG_ERR, "%s, %s", mod.name, dlerror());
479 goto fin;
480 }
481 }
482 mod.mtab = fn(mod.name, &mod.mtabsize, &mod.unregister);
483 if (mod.mtab == NULL || mod.mtabsize == 0) {
484 if (mod.handle != nss_builtin_handle)
485 (void)dlclose(mod.handle);
486 mod.handle = NULL;
487 nss_log(LOG_ERR, "%s, registration failed", mod.name);
488 goto fin;
489 }
490 if (mod.mtabsize > 1)
491 qsort(mod.mtab, mod.mtabsize, sizeof(mod.mtab[0]),
492 mtab_compare);
493fin:
494 _nsmod = vector_append(&mod, _nsmod, &_nsmodsize, sizeof(*_nsmod));
495 vector_sort(_nsmod, _nsmodsize, sizeof(*_nsmod), string_compare);
496}
497
498
499
500static void
501ns_mod_free(ns_mod *mod)
502{
503
504 free(mod->name);
505 if (mod->handle == NULL)
506 return;
507 if (mod->unregister != NULL)
508 mod->unregister(mod->mtab, mod->mtabsize);
509 if (mod->handle != nss_builtin_handle)
510 (void)dlclose(mod->handle);
511}
512
513
514
515/*
516 * Cleanup
517 */
518static void
519nss_atexit(void)
520{
521 int isthreaded;
522
523 isthreaded = __isthreaded;
524 if (isthreaded)
525 (void)_pthread_rwlock_wrlock(&nss_lock);
526 VECTOR_FREE(_nsmap, &_nsmapsize, sizeof(*_nsmap),
527 (vector_free_elem)ns_dbt_free);
528 VECTOR_FREE(_nsmod, &_nsmodsize, sizeof(*_nsmod),
529 (vector_free_elem)ns_mod_free);
530 if (isthreaded)
531 (void)_pthread_rwlock_unlock(&nss_lock);
532}
533
534
535
536/*
537 * Finally, the actual implementation.
538 */
539static nss_method
540nss_method_lookup(const char *source, const char *database,
541 const char *method, const ns_dtab disp_tab[], void **mdata)
542{
543 ns_mod *mod;
544 ns_mtab *match, key;
545 int i;
546
547 if (disp_tab != NULL)
548 for (i = 0; disp_tab[i].src != NULL; i++)
549 if (strcasecmp(source, disp_tab[i].src) == 0) {
550 *mdata = disp_tab[i].mdata;
551 return (disp_tab[i].method);
552 }
553 mod = vector_search(&source, _nsmod, _nsmodsize, sizeof(*_nsmod),
554 string_compare);
555 if (mod != NULL && mod->handle != NULL) {
556 key.database = database;
557 key.name = method;
558 match = bsearch(&key, mod->mtab, mod->mtabsize,
559 sizeof(mod->mtab[0]), mtab_compare);
560 if (match != NULL) {
561 *mdata = match->mdata;
562 return (match->method);
563 }
564 }
565 if (is_dynamic())
566 nss_log(LOG_DEBUG, "%s, %s, %s, not found", source, database,
567 method);
568 *mdata = NULL;
569 return (NULL);
570}
571
572
573__weak_reference(_nsdispatch, nsdispatch);
574
575int
576_nsdispatch(void *retval, const ns_dtab disp_tab[], const char *database,
577 const char *method_name, const ns_src defaults[], ...)
578{
579 va_list ap;
580 const ns_dbt *dbt;
581 const ns_src *srclist;
582 nss_method method;
583 void *mdata;
584 int isthreaded, serrno, i, result, srclistsize;
585
586 isthreaded = __isthreaded;
587 serrno = errno;
588 if (isthreaded) {
589 result = _pthread_rwlock_rdlock(&nss_lock);
590 if (result != 0) {
591 result = NS_UNAVAIL;
592 goto fin;
593 }
594 }
595 result = nss_configure();
596 if (result != 0) {
597 result = NS_UNAVAIL;
598 goto fin;
599 }
600 dbt = vector_search(&database, _nsmap, _nsmapsize, sizeof(*_nsmap),
601 string_compare);
602 if (dbt != NULL) {
603 srclist = dbt->srclist;
604 srclistsize = dbt->srclistsize;
605 } else {
606 srclist = defaults;
607 srclistsize = 0;
608 while (srclist[srclistsize].name != NULL)
609 srclistsize++;
610 }
611 for (i = 0; i < srclistsize; i++) {
612 result = NS_NOTFOUND;
613 method = nss_method_lookup(srclist[i].name, database,
614 method_name, disp_tab, &mdata);
615 if (method != NULL) {
616 va_start(ap, defaults);
617 result = method(retval, mdata, ap);
618 va_end(ap);
619 if (result & (srclist[i].flags))
620 break;
621 }
622 }
623 if (isthreaded)
624 (void)_pthread_rwlock_unlock(&nss_lock);
625fin:
626 errno = serrno;
627 return (result);
628}
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