1 /* $NetBSD: nsdispatch.c,v 1.9 1999/01/25 00:16:17 lukem Exp $ */
4 * SPDX-License-Identifier: BSD-2-Clause-NetBSD
6 * Copyright (c) 1997, 1998, 1999 The NetBSD Foundation, Inc.
9 * This code is derived from software contributed to The NetBSD Foundation
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
21 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
23 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
24 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
25 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
26 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
27 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
31 * POSSIBILITY OF SUCH DAMAGE.
34 * Copyright (c) 2003 Networks Associates Technology, Inc.
35 * All rights reserved.
37 * Portions of this software were developed for the FreeBSD Project by
38 * Jacques A. Vidrine, Safeport Network Services, and Network
39 * Associates Laboratories, the Security Research Division of Network
40 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035
41 * ("CBOSS"), as part of the DARPA CHATS research program.
43 * Redistribution and use in source and binary forms, with or without
44 * modification, are permitted provided that the following conditions
46 * 1. Redistributions of source code must retain the above copyright
47 * notice, this list of conditions and the following disclaimer.
48 * 2. Redistributions in binary form must reproduce the above copyright
49 * notice, this list of conditions and the following disclaimer in the
50 * documentation and/or other materials provided with the distribution.
52 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
53 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
54 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
55 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
56 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
57 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
58 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
59 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
60 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
61 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
65 #include <sys/cdefs.h>
66 __FBSDID("$FreeBSD$");
68 #include "namespace.h"
69 #include <sys/param.h>
78 #include <pthread_np.h>
84 #include "un-namespace.h"
86 #include "libc_private.h"
92 /* Number of elements allocated when we grow a vector */
97 * Global NSS data structures are mostly read-only, but we update
98 * them when we read or re-read the nsswitch.conf.
100 static pthread_rwlock_t nss_lock = PTHREAD_RWLOCK_INITIALIZER;
103 * Runtime determination of whether we are dynamically linked or not.
105 extern int _DYNAMIC __attribute__ ((weak));
106 #define is_dynamic() (&_DYNAMIC != NULL)
109 * default sourcelist: `files'
111 const ns_src __nsdefaultsrc[] = {
112 { NSSRC_FILES, NS_SUCCESS },
116 /* Database, source mappings. */
117 static unsigned int _nsmapsize;
118 static ns_dbt *_nsmap = NULL;
121 static unsigned int _nsmodsize;
122 static ns_mod *_nsmod;
124 /* Placeholder for builtin modules' dlopen `handle'. */
125 static int __nss_builtin_handle;
126 static void *nss_builtin_handle = &__nss_builtin_handle;
130 * Cache lookup cycle prevention function - if !NULL then no cache lookups
133 static void *nss_cache_cycle_prevention_func = NULL;
137 * We keep track of nsdispatch() nesting depth in dispatch_depth. When a
138 * fallback method is invoked from nsdispatch(), we temporarily set
139 * fallback_depth to the current dispatch depth plus one. Subsequent
140 * calls at that exact depth will run in fallback mode (restricted to the
141 * same source as the call that was handled by the fallback method), while
142 * calls below that depth will be handled normally, allowing fallback
143 * methods to perform arbitrary lookups.
149 static void fb_endstate(void *);
150 NSS_TLS_HANDLING(fb);
153 * Attempt to spew relatively uniform messages to syslog.
155 #define nss_log(level, fmt, ...) \
156 syslog((level), "NSSWITCH(%s): " fmt, __func__, __VA_ARGS__)
157 #define nss_log_simple(level, s) \
158 syslog((level), "NSSWITCH(%s): " s, __func__)
161 * Dynamically growable arrays are used for lists of databases, sources,
162 * and modules. The following `vector' interface is used to isolate the
165 typedef int (*vector_comparison)(const void *, const void *);
166 typedef void (*vector_free_elem)(void *);
167 static void vector_sort(void *, unsigned int, size_t,
169 static void vector_free(void *, unsigned int *, size_t,
171 static void *vector_ref(unsigned int, void *, unsigned int, size_t);
172 static void *vector_search(const void *, void *, unsigned int, size_t,
174 static void *vector_append(const void *, void *, unsigned int *, size_t);
178 * Internal interfaces.
180 static int string_compare(const void *, const void *);
181 static int mtab_compare(const void *, const void *);
182 static int nss_configure(void);
183 static void ns_dbt_free(ns_dbt *);
184 static void ns_mod_free(ns_mod *);
185 static void ns_src_free(ns_src **, int);
186 static void nss_load_builtin_modules(void);
187 static void nss_load_module(const char *, nss_module_register_fn);
188 static void nss_atexit(void);
190 extern FILE *_nsyyin;
194 * The vector operations
197 vector_sort(void *vec, unsigned int count, size_t esize,
198 vector_comparison comparison)
200 qsort(vec, count, esize, comparison);
205 vector_search(const void *key, void *vec, unsigned int count, size_t esize,
206 vector_comparison comparison)
208 return (bsearch(key, vec, count, esize, comparison));
213 vector_append(const void *elem, void *vec, unsigned int *count, size_t esize)
217 if ((*count % ELEMSPERCHUNK) == 0) {
218 p = reallocarray(vec, *count + ELEMSPERCHUNK, esize);
220 nss_log_simple(LOG_ERR, "memory allocation failure");
225 memmove((void *)(((uintptr_t)vec) + (*count * esize)), elem, esize);
232 vector_ref(unsigned int i, void *vec, unsigned int count, size_t esize)
235 return (void *)((uintptr_t)vec + (i * esize));
241 #define VECTOR_FREE(v, c, s, f) \
242 do { vector_free(v, c, s, f); v = NULL; } while (0)
244 vector_free(void *vec, unsigned int *count, size_t esize,
245 vector_free_elem free_elem)
250 for (i = 0; i < *count; i++) {
251 elem = vector_ref(i, vec, *count, esize);
260 * Comparison functions for vector_search.
263 string_compare(const void *a, const void *b)
265 return (strcasecmp(*(const char * const *)a, *(const char * const *)b));
270 mtab_compare(const void *a, const void *b)
274 cmp = strcmp(((const ns_mtab *)a)->name, ((const ns_mtab *)b)->name);
278 return (strcmp(((const ns_mtab *)a)->database,
279 ((const ns_mtab *)b)->database));
283 * NSS nsmap management.
286 _nsdbtaddsrc(ns_dbt *dbt, const ns_src *src)
290 dbt->srclist = vector_append(src, dbt->srclist, &dbt->srclistsize,
292 modp = vector_search(&src->name, _nsmod, _nsmodsize, sizeof(*_nsmod),
295 nss_load_module(src->name, NULL);
301 _nsdbtdump(const ns_dbt *dbt)
305 printf("%s (%d source%s):", dbt->name, dbt->srclistsize,
306 dbt->srclistsize == 1 ? "" : "s");
307 for (i = 0; i < (int)dbt->srclistsize; i++) {
308 printf(" %s", dbt->srclist[i].name);
309 if (!(dbt->srclist[i].flags &
310 (NS_UNAVAIL|NS_NOTFOUND|NS_TRYAGAIN)) &&
311 (dbt->srclist[i].flags & NS_SUCCESS))
314 if (!(dbt->srclist[i].flags & NS_SUCCESS))
315 printf(" SUCCESS=continue");
316 if (dbt->srclist[i].flags & NS_UNAVAIL)
317 printf(" UNAVAIL=return");
318 if (dbt->srclist[i].flags & NS_NOTFOUND)
319 printf(" NOTFOUND=return");
320 if (dbt->srclist[i].flags & NS_TRYAGAIN)
321 printf(" TRYAGAIN=return");
330 * The first time nsdispatch is called (during a process's lifetime,
331 * or after nsswitch.conf has been updated), nss_configure will
332 * prepare global data needed by NSS.
337 static time_t confmod;
338 #ifndef NS_REREAD_CONF
339 static int already_initialized = 0;
342 int result, isthreaded;
349 isthreaded = __isthreaded;
350 #if defined(_NSS_DEBUG) && defined(_NSS_SHOOT_FOOT)
351 /* NOTE WELL: THIS IS A SECURITY HOLE. This must only be built
352 * for debugging purposes and MUST NEVER be used in production.
354 path = getenv("NSSWITCH_CONF");
357 path = _PATH_NS_CONF;
358 #ifndef NS_REREAD_CONF
360 * Define NS_REREAD_CONF to have nsswitch notice changes
361 * to nsswitch.conf(5) during runtime. This involves calling
362 * stat(2) every time, which can result in performance hit.
364 if (already_initialized)
366 already_initialized = 1;
367 #endif /* NS_REREAD_CONF */
368 if (stat(path, &statbuf) != 0)
370 if (statbuf.st_mtime <= confmod)
373 (void)_pthread_rwlock_unlock(&nss_lock);
374 result = _pthread_rwlock_wrlock(&nss_lock);
377 if (stat(path, &statbuf) != 0)
379 if (statbuf.st_mtime <= confmod)
382 _nsyyin = fopen(path, "re");
385 VECTOR_FREE(_nsmap, &_nsmapsize, sizeof(*_nsmap),
386 (vector_free_elem)ns_dbt_free);
387 VECTOR_FREE(_nsmod, &_nsmodsize, sizeof(*_nsmod),
388 (vector_free_elem)ns_mod_free);
390 (void)atexit(nss_atexit);
391 nss_load_builtin_modules();
393 (void)fclose(_nsyyin);
394 vector_sort(_nsmap, _nsmapsize, sizeof(*_nsmap), string_compare);
395 confmod = statbuf.st_mtime;
398 handle = libc_dlopen(NULL, RTLD_LAZY | RTLD_GLOBAL);
399 if (handle != NULL) {
400 nss_cache_cycle_prevention_func = dlsym(handle,
401 "_nss_cache_cycle_prevention_function");
407 (void)_pthread_rwlock_unlock(&nss_lock);
409 result = _pthread_rwlock_rdlock(&nss_lock);
416 _nsdbtput(const ns_dbt *dbt)
421 for (i = 0; i < _nsmapsize; i++) {
422 p = vector_ref(i, _nsmap, _nsmapsize, sizeof(*_nsmap));
423 if (string_compare(&dbt->name, &p->name) == 0) {
424 /* overwrite existing entry */
425 if (p->srclist != NULL)
426 ns_src_free(&p->srclist, p->srclistsize);
427 memmove(p, dbt, sizeof(*dbt));
431 _nsmap = vector_append(dbt, _nsmap, &_nsmapsize, sizeof(*_nsmap));
436 ns_dbt_free(ns_dbt *dbt)
438 ns_src_free(&dbt->srclist, dbt->srclistsize);
440 free((void *)dbt->name);
445 ns_src_free(ns_src **src, int srclistsize)
449 for (i = 0; i < srclistsize; i++)
450 if ((*src)[i].name != NULL)
451 /* This one was allocated by nslexer. You'll just
454 free((void *)((*src)[i].name));
462 * NSS module management.
464 /* The built-in NSS modules are all loaded at once. */
465 #define NSS_BACKEND(name, reg) \
466 ns_mtab *reg(unsigned int *, nss_module_unregister_fn *);
467 #include "nss_backends.h"
471 nss_load_builtin_modules(void)
473 #define NSS_BACKEND(name, reg) nss_load_module(#name, reg);
474 #include "nss_backends.h"
479 /* Load a built-in or dynamically linked module. If the `reg_fn'
480 * argument is non-NULL, assume a built-in module and use reg_fn to
481 * register it. Otherwise, search for a dynamic NSS module.
484 nss_load_module(const char *source, nss_module_register_fn reg_fn)
488 nss_module_register_fn fn;
490 memset(&mod, 0, sizeof(mod));
491 mod.name = strdup(source);
492 if (mod.name == NULL) {
493 nss_log_simple(LOG_ERR, "memory allocation failure");
496 if (reg_fn != NULL) {
497 /* The placeholder is required, as a NULL handle
498 * represents an invalid module.
500 mod.handle = nss_builtin_handle;
502 } else if (!is_dynamic()) {
504 } else if (strcmp(source, NSSRC_CACHE) == 0 ||
505 strcmp(source, NSSRC_COMPAT) == 0 ||
506 strcmp(source, NSSRC_DB) == 0 ||
507 strcmp(source, NSSRC_DNS) == 0 ||
508 strcmp(source, NSSRC_FILES) == 0 ||
509 strcmp(source, NSSRC_NIS) == 0) {
511 * Avoid calling dlopen(3) for built-in modules.
515 if (snprintf(buf, sizeof(buf), "nss_%s.so.%d", mod.name,
516 NSS_MODULE_INTERFACE_VERSION) >= (int)sizeof(buf))
518 mod.handle = libc_dlopen(buf, RTLD_LOCAL|RTLD_LAZY);
519 if (mod.handle == NULL) {
521 /* This gets pretty annoying since the built-in
522 * sources aren't modules yet.
524 nss_log(LOG_DEBUG, "%s, %s", mod.name, dlerror());
528 fn = (nss_module_register_fn)dlfunc(mod.handle,
529 "nss_module_register");
531 (void)dlclose(mod.handle);
533 nss_log(LOG_ERR, "%s, %s", mod.name, dlerror());
537 mod.mtab = fn(mod.name, &mod.mtabsize, &mod.unregister);
538 if (mod.mtab == NULL || mod.mtabsize == 0) {
539 if (mod.handle != nss_builtin_handle)
540 (void)dlclose(mod.handle);
542 nss_log(LOG_ERR, "%s, registration failed", mod.name);
545 if (mod.mtabsize > 1)
546 qsort(mod.mtab, mod.mtabsize, sizeof(mod.mtab[0]),
549 _nsmod = vector_append(&mod, _nsmod, &_nsmodsize, sizeof(*_nsmod));
550 vector_sort(_nsmod, _nsmodsize, sizeof(*_nsmod), string_compare);
553 static int exiting = 0;
556 ns_mod_free(ns_mod *mod)
560 if (mod->handle == NULL)
562 if (mod->unregister != NULL)
563 mod->unregister(mod->mtab, mod->mtabsize);
564 if (mod->handle != nss_builtin_handle && !exiting)
565 (void)dlclose(mod->handle);
577 isthreaded = __isthreaded;
579 (void)_pthread_rwlock_wrlock(&nss_lock);
580 VECTOR_FREE(_nsmap, &_nsmapsize, sizeof(*_nsmap),
581 (vector_free_elem)ns_dbt_free);
582 VECTOR_FREE(_nsmod, &_nsmodsize, sizeof(*_nsmod),
583 (vector_free_elem)ns_mod_free);
585 (void)_pthread_rwlock_unlock(&nss_lock);
589 * Finally, the actual implementation.
592 nss_method_lookup(const char *source, const char *database,
593 const char *method, const ns_dtab disp_tab[], void **mdata)
599 if (disp_tab != NULL)
600 for (i = 0; disp_tab[i].src != NULL; i++)
601 if (strcasecmp(source, disp_tab[i].src) == 0) {
602 *mdata = disp_tab[i].mdata;
603 return (disp_tab[i].method);
605 mod = vector_search(&source, _nsmod, _nsmodsize, sizeof(*_nsmod),
607 if (mod != NULL && mod->handle != NULL) {
608 key.database = database;
610 match = bsearch(&key, mod->mtab, mod->mtabsize,
611 sizeof(mod->mtab[0]), mtab_compare);
613 *mdata = match->mdata;
614 return (match->method);
628 __weak_reference(_nsdispatch, nsdispatch);
631 _nsdispatch(void *retval, const ns_dtab disp_tab[], const char *database,
632 const char *method_name, const ns_src defaults[], ...)
636 const ns_src *srclist;
637 nss_method method, fb_method;
639 int isthreaded, serrno, i, result, srclistsize;
644 nss_cache_data cache_data;
645 nss_cache_data *cache_data_p;
652 isthreaded = __isthreaded;
655 result = _pthread_rwlock_rdlock(&nss_lock);
662 result = fb_getstate(&st);
668 result = nss_configure();
673 ++st->dispatch_depth;
674 if (st->dispatch_depth > st->fallback_depth) {
675 dbt = vector_search(&database, _nsmap, _nsmapsize, sizeof(*_nsmap),
677 fb_method = nss_method_lookup(NSSRC_FALLBACK, database,
678 method_name, disp_tab, &mdata);
682 srclist = dbt->srclist;
683 srclistsize = dbt->srclistsize;
687 while (srclist[srclistsize].name != NULL)
695 for (i = 0; i < srclistsize; i++) {
696 result = NS_NOTFOUND;
697 method = nss_method_lookup(srclist[i].name, database,
698 method_name, disp_tab, &mdata);
700 if (method != NULL) {
702 if (strcmp(srclist[i].name, NSSRC_CACHE) == 0 &&
703 nss_cache_cycle_prevention_func == NULL) {
704 #ifdef NS_STRICT_LIBC_EID_CHECKING
705 if (issetugid() != 0)
710 memset(&cache_data, 0, sizeof(nss_cache_data));
711 cache_data.info = (nss_cache_info const *)mdata;
712 cache_data_p = &cache_data;
714 va_start(ap, defaults);
715 if (cache_data.info->id_func != NULL)
716 result = __nss_common_cache_read(retval,
718 else if (cache_data.info->marshal_func != NULL)
719 result = __nss_mp_cache_read(retval,
722 result = __nss_mp_cache_end(retval,
728 va_start(ap, defaults);
729 result = method(retval, mdata, ap);
732 #else /* NS_CACHING */
734 va_start(ap, defaults);
735 result = method(retval, mdata, ap);
737 #endif /* NS_CACHING */
739 if (result & (srclist[i].flags))
742 if (fb_method != NULL) {
743 saved_depth = st->fallback_depth;
744 st->fallback_depth = st->dispatch_depth + 1;
745 va_start(ap, defaults);
746 result = fb_method(retval,
747 (void *)srclist[i].name, ap);
749 st->fallback_depth = saved_depth;
751 nss_log(LOG_DEBUG, "%s, %s, %s, not found, "
752 "and no fallback provided",
753 srclist[i].name, database, method_name);
758 if (cache_data_p != NULL &&
759 (result & (NS_NOTFOUND | NS_SUCCESS)) && cache_flag == 0) {
760 va_start(ap, defaults);
761 if (result == NS_SUCCESS) {
762 if (cache_data.info->id_func != NULL)
763 __nss_common_cache_write(retval, cache_data_p,
765 else if (cache_data.info->marshal_func != NULL)
766 __nss_mp_cache_write(retval, cache_data_p, ap);
767 } else if (result == NS_NOTFOUND) {
768 if (cache_data.info->id_func == NULL) {
769 if (cache_data.info->marshal_func != NULL)
770 __nss_mp_cache_write_submit(retval,
773 __nss_common_cache_write_negative(cache_data_p);
777 #endif /* NS_CACHING */
780 (void)_pthread_rwlock_unlock(&nss_lock);
781 --st->dispatch_depth;