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
);