1 /* $NetBSD: nsdispatch.c,v 1.9 1999/01/25 00:16:17 lukem Exp $ */
4 * Copyright (c) 1997, 1998, 1999 The NetBSD Foundation, Inc.
7 * This code is derived from software contributed to The NetBSD Foundation
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
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.
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.
39 * Copyright (c) 2003 Networks Associates Technology, Inc.
40 * All rights reserved.
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.
48 * Redistribution and use in source and binary forms, with or without
49 * modification, are permitted provided that the following conditions
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.
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
69 * $FreeBSD: src/lib/libc/net/nsdispatch.c,v 1.17 2008/05/02 14:51:22 jhb Exp $
72 #include "namespace.h"
73 #include <sys/param.h>
87 #include "un-namespace.h"
88 #include "libc_private.h"
94 /* Number of elements allocated when we grow a vector */
99 * Global NSS data structures are mostly read-only, but we update
100 * them when we read or re-read the nsswitch.conf.
102 static pthread_rwlock_t nss_lock = PTHREAD_RWLOCK_INITIALIZER;
105 * Runtime determination of whether we are dynamically linked or not.
107 extern int _DYNAMIC __attribute__ ((weak));
108 #define is_dynamic() (&_DYNAMIC != NULL)
111 * default sourcelist: `files'
113 const ns_src __nsdefaultsrc[] = {
114 { NSSRC_FILES, NS_SUCCESS },
118 /* Database, source mappings. */
119 static unsigned int _nsmapsize;
120 static ns_dbt *_nsmap = NULL;
123 static unsigned int _nsmodsize;
124 static ns_mod *_nsmod;
126 /* Placeholder for builtin modules' dlopen `handle'. */
127 static int __nss_builtin_handle;
128 static void *nss_builtin_handle = &__nss_builtin_handle;
132 * Cache lookup cycle prevention function - if !NULL then no cache lookups
135 static void *nss_cache_cycle_prevention_func = NULL;
139 * When this is set to 1, nsdispatch won't use nsswitch.conf
140 * but will consult the 'defaults' source list only.
141 * NOTE: nested fallbacks (when nsdispatch calls fallback functions,
142 * which in turn calls nsdispatch, which should call fallback
143 * function) are not supported
145 static int fallback_dispatch = 0;
148 * Attempt to spew relatively uniform messages to syslog.
150 #define nss_log(level, fmt, ...) \
151 syslog((level), "NSSWITCH(%s): " fmt, __func__, __VA_ARGS__)
152 #define nss_log_simple(level, s) \
153 syslog((level), "NSSWITCH(%s): " s, __func__)
156 * Dynamically growable arrays are used for lists of databases, sources,
157 * and modules. The following `vector' interface is used to isolate the
160 typedef int (*vector_comparison)(const void *, const void *);
161 typedef void (*vector_free_elem)(void *);
162 static void vector_sort(void *, unsigned int, size_t,
164 static void vector_free(void *, unsigned int *, size_t,
166 static void *vector_ref(unsigned int, void *, unsigned int, size_t);
167 static void *vector_search(const void *, void *, unsigned int, size_t,
169 static void *vector_append(const void *, void *, unsigned int *, size_t);
173 * Internal interfaces.
175 static int string_compare(const void *, const void *);
176 static int mtab_compare(const void *, const void *);
177 static int nss_configure(void);
178 static void ns_dbt_free(ns_dbt *);
179 static void ns_mod_free(ns_mod *);
180 static void ns_src_free(ns_src **, int);
181 static void nss_load_builtin_modules(void);
182 static void nss_load_module(const char *, nss_module_register_fn);
183 static void nss_atexit(void);
185 extern FILE *_nsyyin;
189 * The vector operations
192 vector_sort(void *vec, unsigned int count, size_t esize,
193 vector_comparison comparison)
195 qsort(vec, count, esize, comparison);
200 vector_search(const void *key, void *vec, unsigned int count, size_t esize,
201 vector_comparison comparison)
203 return (bsearch(key, vec, count, esize, comparison));
208 vector_append(const void *elem, void *vec, unsigned int *count, size_t esize)
212 if ((*count % ELEMSPERCHUNK) == 0) {
213 p = realloc(vec, (*count + ELEMSPERCHUNK) * esize);
215 nss_log_simple(LOG_ERR, "memory allocation failure");
220 memmove((void *)(((uintptr_t)vec) + (*count * esize)), elem, esize);
227 vector_ref(unsigned int i, void *vec, unsigned int count, size_t esize)
230 return (void *)((uintptr_t)vec + (i * esize));
236 #define VECTOR_FREE(v, c, s, f) \
237 do { vector_free(v, c, s, f); v = NULL; } while (0)
239 vector_free(void *vec, unsigned int *count, size_t esize,
240 vector_free_elem free_elem)
245 for (i = 0; i < *count; i++) {
246 elem = vector_ref(i, vec, *count, esize);
255 * Comparison functions for vector_search.
258 string_compare(const void *a, const void *b)
260 return (strcasecmp(*(const char * const *)a, *(const char * const *)b));
265 mtab_compare(const void *a, const void *b)
269 cmp = strcmp(((const ns_mtab *)a)->name, ((const ns_mtab *)b)->name);
273 return (strcmp(((const ns_mtab *)a)->database,
274 ((const ns_mtab *)b)->database));
278 * NSS nsmap management.
281 _nsdbtaddsrc(ns_dbt *dbt, const ns_src *src)
285 dbt->srclist = vector_append(src, dbt->srclist, &dbt->srclistsize,
287 modp = vector_search(&src->name, _nsmod, _nsmodsize, sizeof(*_nsmod),
290 nss_load_module(src->name, NULL);
296 _nsdbtdump(const ns_dbt *dbt)
300 printf("%s (%d source%s):", dbt->name, dbt->srclistsize,
301 dbt->srclistsize == 1 ? "" : "s");
302 for (i = 0; i < (int)dbt->srclistsize; i++) {
303 printf(" %s", dbt->srclist[i].name);
304 if (!(dbt->srclist[i].flags &
305 (NS_UNAVAIL|NS_NOTFOUND|NS_TRYAGAIN)) &&
306 (dbt->srclist[i].flags & NS_SUCCESS))
309 if (!(dbt->srclist[i].flags & NS_SUCCESS))
310 printf(" SUCCESS=continue");
311 if (dbt->srclist[i].flags & NS_UNAVAIL)
312 printf(" UNAVAIL=return");
313 if (dbt->srclist[i].flags & NS_NOTFOUND)
314 printf(" NOTFOUND=return");
315 if (dbt->srclist[i].flags & NS_TRYAGAIN)
316 printf(" TRYAGAIN=return");
325 * The first time nsdispatch is called (during a process's lifetime,
326 * or after nsswitch.conf has been updated), nss_configure will
327 * prepare global data needed by NSS.
332 static pthread_mutex_t conf_lock = PTHREAD_MUTEX_INITIALIZER;
333 static time_t confmod;
335 int result, isthreaded;
342 isthreaded = __isthreaded;
343 #if defined(_NSS_DEBUG) && defined(_NSS_SHOOT_FOOT)
344 /* NOTE WELL: THIS IS A SECURITY HOLE. This must only be built
345 * for debugging purposes and MUST NEVER be used in production.
347 path = getenv("NSSWITCH_CONF");
350 path = _PATH_NS_CONF;
351 if (stat(path, &statbuf) != 0)
353 if (statbuf.st_mtime <= confmod)
356 result = _pthread_mutex_trylock(&conf_lock);
359 _pthread_rwlock_unlock(&nss_lock);
360 result = _pthread_rwlock_wrlock(&nss_lock);
364 _nsyyin = fopen(path, "r");
367 VECTOR_FREE(_nsmap, &_nsmapsize, sizeof(*_nsmap),
368 (vector_free_elem)ns_dbt_free);
369 VECTOR_FREE(_nsmod, &_nsmodsize, sizeof(*_nsmod),
370 (vector_free_elem)ns_mod_free);
371 nss_load_builtin_modules();
374 vector_sort(_nsmap, _nsmapsize, sizeof(*_nsmap), string_compare);
377 confmod = statbuf.st_mtime;
380 handle = dlopen(NULL, RTLD_LAZY | RTLD_GLOBAL);
381 if (handle != NULL) {
382 nss_cache_cycle_prevention_func = dlsym(handle,
383 "_nss_cache_cycle_prevention_function");
389 _pthread_rwlock_unlock(&nss_lock);
391 result = _pthread_rwlock_rdlock(&nss_lock);
395 _pthread_mutex_unlock(&conf_lock);
401 _nsdbtput(const ns_dbt *dbt)
406 for (i = 0; i < _nsmapsize; i++) {
407 p = vector_ref(i, _nsmap, _nsmapsize, sizeof(*_nsmap));
408 if (string_compare(&dbt->name, &p->name) == 0) {
409 /* overwrite existing entry */
410 if (p->srclist != NULL)
411 ns_src_free(&p->srclist, p->srclistsize);
412 memmove(p, dbt, sizeof(*dbt));
416 _nsmap = vector_append(dbt, _nsmap, &_nsmapsize, sizeof(*_nsmap));
421 ns_dbt_free(ns_dbt *dbt)
423 ns_src_free(&dbt->srclist, dbt->srclistsize);
425 free((void *)dbt->name);
430 ns_src_free(ns_src **src, int srclistsize)
434 for (i = 0; i < srclistsize; i++)
435 if ((*src)[i].name != NULL)
436 /* This one was allocated by nslexer. You'll just
439 free((void *)((*src)[i].name));
447 * NSS module management.
449 /* The built-in NSS modules are all loaded at once. */
450 #define NSS_BACKEND(name, reg) \
451 ns_mtab *reg(unsigned int *, nss_module_unregister_fn *);
452 #include "nss_backends.h"
456 nss_load_builtin_modules(void)
458 #define NSS_BACKEND(name, reg) nss_load_module(#name, reg);
459 #include "nss_backends.h"
464 /* Load a built-in or dynamically linked module. If the `reg_fn'
465 * argument is non-NULL, assume a built-in module and use reg_fn to
466 * register it. Otherwise, search for a dynamic NSS module.
469 nss_load_module(const char *source, nss_module_register_fn reg_fn)
473 nss_module_register_fn fn;
475 memset(&mod, 0, sizeof(mod));
476 mod.name = strdup(source);
477 if (mod.name == NULL) {
478 nss_log_simple(LOG_ERR, "memory allocation failure");
481 if (reg_fn != NULL) {
482 /* The placeholder is required, as a NULL handle
483 * represents an invalid module.
485 mod.handle = nss_builtin_handle;
487 } else if (!is_dynamic())
490 if (snprintf(buf, sizeof(buf), "nss_%s.so.%d", mod.name,
491 NSS_MODULE_INTERFACE_VERSION) >= (int)sizeof(buf))
493 mod.handle = dlopen(buf, RTLD_LOCAL|RTLD_LAZY);
494 if (mod.handle == NULL) {
496 /* This gets pretty annoying since the built-in
497 * sources aren't modules yet.
499 nss_log(LOG_DEBUG, "%s, %s", mod.name, dlerror());
503 fn = (nss_module_register_fn)dlfunc(mod.handle,
504 "nss_module_register");
508 nss_log(LOG_ERR, "%s, %s", mod.name, dlerror());
512 mod.mtab = fn(mod.name, &mod.mtabsize, &mod.unregister);
513 if (mod.mtab == NULL || mod.mtabsize == 0) {
514 if (mod.handle != nss_builtin_handle)
517 nss_log(LOG_ERR, "%s, registration failed", mod.name);
520 if (mod.mtabsize > 1)
521 qsort(mod.mtab, mod.mtabsize, sizeof(mod.mtab[0]),
524 _nsmod = vector_append(&mod, _nsmod, &_nsmodsize, sizeof(*_nsmod));
525 vector_sort(_nsmod, _nsmodsize, sizeof(*_nsmod), string_compare);
531 ns_mod_free(ns_mod *mod)
535 if (mod->handle == NULL)
537 if (mod->unregister != NULL)
538 mod->unregister(mod->mtab, mod->mtabsize);
539 if (mod->handle != nss_builtin_handle)
540 dlclose(mod->handle);
553 isthreaded = __isthreaded;
555 _pthread_rwlock_wrlock(&nss_lock);
556 VECTOR_FREE(_nsmap, &_nsmapsize, sizeof(*_nsmap),
557 (vector_free_elem)ns_dbt_free);
558 VECTOR_FREE(_nsmod, &_nsmodsize, sizeof(*_nsmod),
559 (vector_free_elem)ns_mod_free);
561 _pthread_rwlock_unlock(&nss_lock);
567 * Finally, the actual implementation.
570 nss_method_lookup(const char *source, const char *database,
571 const char *method, const ns_dtab disp_tab[], void **mdata)
577 if (disp_tab != NULL)
578 for (i = 0; disp_tab[i].src != NULL; i++)
579 if (strcasecmp(source, disp_tab[i].src) == 0) {
580 *mdata = disp_tab[i].mdata;
581 return (disp_tab[i].method);
583 mod = vector_search(&source, _nsmod, _nsmodsize, sizeof(*_nsmod),
585 if (mod != NULL && mod->handle != NULL) {
586 key.database = database;
588 match = bsearch(&key, mod->mtab, mod->mtabsize,
589 sizeof(mod->mtab[0]), mtab_compare);
591 *mdata = match->mdata;
592 return (match->method);
601 __weak_reference(_nsdispatch, nsdispatch);
604 _nsdispatch(void *retval, const ns_dtab disp_tab[], const char *database,
605 const char *method_name, const ns_src defaults[], ...)
609 const ns_src *srclist;
610 nss_method method, fb_method;
612 int isthreaded, serrno, i, result, srclistsize;
615 nss_cache_data cache_data;
616 nss_cache_data *cache_data_p;
623 isthreaded = __isthreaded;
626 result = _pthread_rwlock_rdlock(&nss_lock);
632 result = nss_configure();
637 if (fallback_dispatch == 0) {
638 dbt = vector_search(&database, _nsmap, _nsmapsize, sizeof(*_nsmap),
640 fb_method = nss_method_lookup(NSSRC_FALLBACK, database,
641 method_name, disp_tab, &mdata);
645 srclist = dbt->srclist;
646 srclistsize = dbt->srclistsize;
650 while (srclist[srclistsize].name != NULL)
658 for (i = 0; i < srclistsize; i++) {
659 result = NS_NOTFOUND;
660 method = nss_method_lookup(srclist[i].name, database,
661 method_name, disp_tab, &mdata);
663 if (method != NULL) {
665 if (strcmp(srclist[i].name, NSSRC_CACHE) == 0 &&
666 nss_cache_cycle_prevention_func == NULL) {
667 #ifdef NS_STRICT_LIBC_EID_CHECKING
668 if (issetugid() != 0)
673 memset(&cache_data, 0, sizeof(nss_cache_data));
674 cache_data.info = (nss_cache_info const *)mdata;
675 cache_data_p = &cache_data;
677 va_start(ap, defaults);
678 if (cache_data.info->id_func != NULL)
679 result = __nss_common_cache_read(retval,
681 else if (cache_data.info->marshal_func != NULL)
682 result = __nss_mp_cache_read(retval,
685 result = __nss_mp_cache_end(retval,
690 va_start(ap, defaults);
691 result = method(retval, mdata, ap);
694 #else /* NS_CACHING */
695 va_start(ap, defaults);
696 result = method(retval, mdata, ap);
698 #endif /* NS_CACHING */
700 if (result & (srclist[i].flags))
703 if (fb_method != NULL) {
704 fallback_dispatch = 1;
705 va_start(ap, defaults);
706 result = fb_method(retval,
707 (void *)srclist[i].name, ap);
709 fallback_dispatch = 0;
711 nss_log(LOG_DEBUG, "%s, %s, %s, not found, "
712 "and no fallback provided",
713 srclist[i].name, database, method_name);
718 if (cache_data_p != NULL &&
719 (result & (NS_NOTFOUND | NS_SUCCESS)) && cache_flag == 0) {
720 va_start(ap, defaults);
721 if (result == NS_SUCCESS) {
722 if (cache_data.info->id_func != NULL)
723 __nss_common_cache_write(retval, cache_data_p,
725 else if (cache_data.info->marshal_func != NULL)
726 __nss_mp_cache_write(retval, cache_data_p, ap);
727 } else if (result == NS_NOTFOUND) {
728 if (cache_data.info->id_func == NULL) {
729 if (cache_data.info->marshal_func != NULL)
730 __nss_mp_cache_write_submit(retval,
733 __nss_common_cache_write_negative(cache_data_p);
737 #endif /* NS_CACHING */
740 _pthread_rwlock_unlock(&nss_lock);