lib/libc/net/nsdispatch.c

   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  * $FreeBSD: src/lib/libc/net/nsdispatch.c,v 1.17 2008/05/02 14:51:22 jhb Exp $
  70  */
  71
  72 #include "namespace.h"
  73 #include <sys/param.h>
  74 #include <sys/stat.h>
  75
  76 #include <dlfcn.h>
  77 #include <errno.h>
  78 #include <fcntl.h>
  79 #define _NS_PRIVATE
  80 #include <nsswitch.h>
  81 #include <pthread.h>
  82 #include <stdio.h>
  83 #include <stdlib.h>
  84 #include <string.h>
  85 #include <syslog.h>
  86 #include <unistd.h>
  87 #include "un-namespace.h"
  88 #include "libc_private.h"
  89 #ifdef NS_CACHING
  90 #include "nscache.h"
  91 #endif
  92
  93 enum _nss_constants {
  94         /* Number of elements allocated when we grow a vector */
  95         ELEMSPERCHUNK = 8
  96 };
  97
  98 /*
  99  * Global NSS data structures are mostly read-only, but we update
 100  * them when we read or re-read the nsswitch.conf.
 101  */
 102 static  pthread_rwlock_t        nss_lock = PTHREAD_RWLOCK_INITIALIZER;
 103
 104 /*
 105  * Runtime determination of whether we are dynamically linked or not.
 106  */
 107 extern  int             _DYNAMIC __attribute__ ((weak));
 108 #define is_dynamic()    (&_DYNAMIC != NULL)
 109
 110 /*
 111  * default sourcelist: `files'
 112  */
 113 const ns_src __nsdefaultsrc[] = {
 114         { NSSRC_FILES, NS_SUCCESS },
 115         { 0 },
 116 };
 117
 118 /* Database, source mappings. */
 119 static  unsigned int             _nsmapsize;
 120 static  ns_dbt                  *_nsmap = NULL;
 121
 122 /* NSS modules. */
 123 static  unsigned int             _nsmodsize;
 124 static  ns_mod                  *_nsmod;
 125
 126 /* Placeholder for builtin modules' dlopen `handle'. */
 127 static  int                      __nss_builtin_handle;
 128 static  void                    *nss_builtin_handle = &__nss_builtin_handle;
 129
 130 #ifdef NS_CACHING
 131 /*
 132  * Cache lookup cycle prevention function - if !NULL then no cache lookups
 133  * will be made
 134  */
 135 static  void                    *nss_cache_cycle_prevention_func = NULL;
 136 #endif
 137
 138 /*
 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
 144  */
 145 static  int                     fallback_dispatch = 0;
 146
 147 /*
 148  * Attempt to spew relatively uniform messages to syslog.
 149  */
 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__)
 154
 155 /*
 156  * Dynamically growable arrays are used for lists of databases, sources,
 157  * and modules.  The following `vector' interface is used to isolate the
 158  * common operations.
 159  */
 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,
 163                     vector_comparison);
 164 static  void      vector_free(void *, unsigned int *, size_t,
 165                     vector_free_elem);
 166 static  void     *vector_ref(unsigned int, void *, unsigned int, size_t);
 167 static  void     *vector_search(const void *, void *, unsigned int, size_t,
 168                     vector_comparison);
 169 static  void     *vector_append(const void *, void *, unsigned int *, size_t);
 170
 171
 172 /*
 173  * Internal interfaces.
 174  */
 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);
 184 /* nsparser */
 185 extern  FILE    *_nsyyin;
 186
 187
 188 /*
 189  * The vector operations
 190  */
 191 static void
 192 vector_sort(void *vec, unsigned int count, size_t esize,
 193     vector_comparison comparison)
 194 {
 195         qsort(vec, count, esize, comparison);
 196 }
 197
 198
 199 static void *
 200 vector_search(const void *key, void *vec, unsigned int count, size_t esize,
 201     vector_comparison comparison)
 202 {
 203         return (bsearch(key, vec, count, esize, comparison));
 204 }
 205
 206
 207 static void *
 208 vector_append(const void *elem, void *vec, unsigned int *count, size_t esize)
 209 {
 210         void    *p;
 211
 212         if ((*count % ELEMSPERCHUNK) == 0) {
 213                 p = realloc(vec, (*count + ELEMSPERCHUNK) * esize);
 214                 if (p == NULL) {
 215                         nss_log_simple(LOG_ERR, "memory allocation failure");
 216                         return (vec);
 217                 }
 218                 vec = p;
 219         }
 220         memmove((void *)(((uintptr_t)vec) + (*count * esize)), elem, esize);
 221         (*count)++;
 222         return (vec);
 223 }
 224
 225
 226 static void *
 227 vector_ref(unsigned int i, void *vec, unsigned int count, size_t esize)
 228 {
 229         if (i < count)
 230                 return (void *)((uintptr_t)vec + (i * esize));
 231         else
 232                 return (NULL);
 233 }
 234
 235
 236 #define VECTOR_FREE(v, c, s, f) \
 237         do { vector_free(v, c, s, f); v = NULL; } while (0)
 238 static void
 239 vector_free(void *vec, unsigned int *count, size_t esize,
 240     vector_free_elem free_elem)
 241 {
 242         unsigned int     i;
 243         void            *elem;
 244
 245         for (i = 0; i < *count; i++) {
 246                 elem = vector_ref(i, vec, *count, esize);
 247                 if (elem != NULL)
 248                         free_elem(elem);
 249         }
 250         free(vec);
 251         *count = 0;
 252 }
 253
 254 /*
 255  * Comparison functions for vector_search.
 256  */
 257 static int
 258 string_compare(const void *a, const void *b)
 259 {
 260       return (strcasecmp(*(const char * const *)a, *(const char * const *)b));
 261 }
 262
 263
 264 static int
 265 mtab_compare(const void *a, const void *b)
 266 {
 267       int     cmp;
 268
 269       cmp = strcmp(((const ns_mtab *)a)->name, ((const ns_mtab *)b)->name);
 270       if (cmp != 0)
 271               return (cmp);
 272       else
 273               return (strcmp(((const ns_mtab *)a)->database,
 274                   ((const ns_mtab *)b)->database));
 275 }
 276
 277 /*
 278  * NSS nsmap management.
 279  */
 280 void
 281 _nsdbtaddsrc(ns_dbt *dbt, const ns_src *src)
 282 {
 283         const ns_mod    *modp;
 284
 285         dbt->srclist = vector_append(src, dbt->srclist, &dbt->srclistsize,
 286             sizeof(*src));
 287         modp = vector_search(&src->name, _nsmod, _nsmodsize, sizeof(*_nsmod),
 288             string_compare);
 289         if (modp == NULL)
 290                 nss_load_module(src->name, NULL);
 291 }
 292
 293
 294 #ifdef _NSS_DEBUG
 295 void
 296 _nsdbtdump(const ns_dbt *dbt)
 297 {
 298         int i;
 299
 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))
 307                         continue;
 308                 printf(" [");
 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");
 317                 printf(" ]");
 318         }
 319         printf("\n");
 320 }
 321 #endif
 322
 323
 324 /*
 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.
 328  */
 329 static int
 330 nss_configure(void)
 331 {
 332         static pthread_mutex_t conf_lock = PTHREAD_MUTEX_INITIALIZER;
 333         static time_t    confmod;
 334         struct stat      statbuf;
 335         int              result, isthreaded;
 336         const char      *path;
 337 #ifdef NS_CACHING
 338         void            *handle;
 339 #endif
 340
 341         result = 0;
 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.
 346          */
 347         path = getenv("NSSWITCH_CONF");
 348         if (path == NULL)
 349 #endif
 350         path = _PATH_NS_CONF;
 351         if (stat(path, &statbuf) != 0)
 352                 return (0);
 353         if (statbuf.st_mtime <= confmod)
 354                 return (0);
 355         if (isthreaded) {
 356             result = _pthread_mutex_trylock(&conf_lock);
 357             if (result != 0)
 358                     return (0);
 359             _pthread_rwlock_unlock(&nss_lock);
 360             result = _pthread_rwlock_wrlock(&nss_lock);
 361             if (result != 0)
 362                     goto fin2;
 363         }
 364         _nsyyin = fopen(path, "r");
 365         if (_nsyyin == NULL)
 366                 goto fin;
 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();
 372         _nsyyparse();
 373         fclose(_nsyyin);
 374         vector_sort(_nsmap, _nsmapsize, sizeof(*_nsmap), string_compare);
 375         if (confmod == 0)
 376                 atexit(nss_atexit);
 377         confmod = statbuf.st_mtime;
 378
 379 #ifdef NS_CACHING
 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");
 384                 dlclose(handle);
 385         }
 386 #endif
 387 fin:
 388         if (isthreaded) {
 389             _pthread_rwlock_unlock(&nss_lock);
 390             if (result == 0)
 391                     result = _pthread_rwlock_rdlock(&nss_lock);
 392         }
 393 fin2:
 394         if (isthreaded)
 395                 _pthread_mutex_unlock(&conf_lock);
 396         return (result);
 397 }
 398
 399
 400 void
 401 _nsdbtput(const ns_dbt *dbt)
 402 {
 403         unsigned int     i;
 404         ns_dbt          *p;
 405
 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));
 413                         return;
 414                 }
 415         }
 416         _nsmap = vector_append(dbt, _nsmap, &_nsmapsize, sizeof(*_nsmap));
 417 }
 418
 419
 420 static void
 421 ns_dbt_free(ns_dbt *dbt)
 422 {
 423         ns_src_free(&dbt->srclist, dbt->srclistsize);
 424         if (dbt->name)
 425                 free((void *)dbt->name);
 426 }
 427
 428
 429 static void
 430 ns_src_free(ns_src **src, int srclistsize)
 431 {
 432         int     i;
 433
 434         for (i = 0; i < srclistsize; i++)
 435                 if ((*src)[i].name != NULL)
 436                         /* This one was allocated by nslexer. You'll just
 437                          * have to trust me.
 438                          */
 439                         free((void *)((*src)[i].name));
 440         free(*src);
 441         *src = NULL;
 442 }
 443
 444
 445
 446 /*
 447  * NSS module management.
 448  */
 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"
 453 #undef NSS_BACKEND
 454
 455 static void
 456 nss_load_builtin_modules(void)
 457 {
 458 #define NSS_BACKEND(name, reg) nss_load_module(#name, reg);
 459 #include "nss_backends.h"
 460 #undef NSS_BACKEND
 461 }
 462
 463
 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.
 467  */
 468 static void
 469 nss_load_module(const char *source, nss_module_register_fn reg_fn)
 470 {
 471         char             buf[PATH_MAX];
 472         ns_mod           mod;
 473         nss_module_register_fn fn;
 474
 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");
 479                 return;
 480         }
 481         if (reg_fn != NULL) {
 482                 /* The placeholder is required, as a NULL handle
 483                  * represents an invalid module.
 484                  */
 485                 mod.handle = nss_builtin_handle;
 486                 fn = reg_fn;
 487         } else if (!is_dynamic())
 488                 goto fin;
 489         else {
 490                 if (snprintf(buf, sizeof(buf), "nss_%s.so.%d", mod.name,
 491                     NSS_MODULE_INTERFACE_VERSION) >= (int)sizeof(buf))
 492                         goto fin;
 493                 mod.handle = dlopen(buf, RTLD_LOCAL|RTLD_LAZY);
 494                 if (mod.handle == NULL) {
 495 #ifdef _NSS_DEBUG
 496                         /* This gets pretty annoying since the built-in
 497                          * sources aren't modules yet.
 498                          */
 499                         nss_log(LOG_DEBUG, "%s, %s", mod.name, dlerror());
 500 #endif
 501                         goto fin;
 502                 }
 503                 fn = (nss_module_register_fn)dlfunc(mod.handle,
 504                     "nss_module_register");
 505                 if (fn == NULL) {
 506                         dlclose(mod.handle);
 507                         mod.handle = NULL;
 508                         nss_log(LOG_ERR, "%s, %s", mod.name, dlerror());
 509                         goto fin;
 510                 }
 511         }
 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)
 515                         dlclose(mod.handle);
 516                 mod.handle = NULL;
 517                 nss_log(LOG_ERR, "%s, registration failed", mod.name);
 518                 goto fin;
 519         }
 520         if (mod.mtabsize > 1)
 521                 qsort(mod.mtab, mod.mtabsize, sizeof(mod.mtab[0]),
 522                     mtab_compare);
 523 fin:
 524         _nsmod = vector_append(&mod, _nsmod, &_nsmodsize, sizeof(*_nsmod));
 525         vector_sort(_nsmod, _nsmodsize, sizeof(*_nsmod), string_compare);
 526 }
 527
 528
 529
 530 static void
 531 ns_mod_free(ns_mod *mod)
 532 {
 533
 534         free(mod->name);
 535         if (mod->handle == NULL)
 536                 return;
 537         if (mod->unregister != NULL)
 538                 mod->unregister(mod->mtab, mod->mtabsize);
 539         if (mod->handle != nss_builtin_handle)
 540                 dlclose(mod->handle);
 541 }
 542
 543
 544
 545 /*
 546  * Cleanup
 547  */
 548 static void
 549 nss_atexit(void)
 550 {
 551         int isthreaded;
 552
 553         isthreaded = __isthreaded;
 554         if (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);
 560         if (isthreaded)
 561                 _pthread_rwlock_unlock(&nss_lock);
 562 }
 563
 564
 565
 566 /*
 567  * Finally, the actual implementation.
 568  */
 569 static nss_method
 570 nss_method_lookup(const char *source, const char *database,
 571     const char *method, const ns_dtab disp_tab[], void **mdata)
 572 {
 573         ns_mod  *mod;
 574         ns_mtab *match, key;
 575         int      i;
 576
 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);
 582                         }
 583         mod = vector_search(&source, _nsmod, _nsmodsize, sizeof(*_nsmod),
 584             string_compare);
 585         if (mod != NULL && mod->handle != NULL) {
 586                 key.database = database;
 587                 key.name = method;
 588                 match = bsearch(&key, mod->mtab, mod->mtabsize,
 589                     sizeof(mod->mtab[0]), mtab_compare);
 590                 if (match != NULL) {
 591                         *mdata = match->mdata;
 592                         return (match->method);
 593                 }
 594         }
 595
 596         *mdata = NULL;
 597         return (NULL);
 598 }
 599
 600
 601 __weak_reference(_nsdispatch, nsdispatch);
 602
 603 int
 604 _nsdispatch(void *retval, const ns_dtab disp_tab[], const char *database,
 605             const char *method_name, const ns_src defaults[], ...)
 606 {
 607         va_list          ap;
 608         const ns_dbt    *dbt;
 609         const ns_src    *srclist;
 610         nss_method       method, fb_method;
 611         void            *mdata;
 612         int              isthreaded, serrno, i, result, srclistsize;
 613
 614 #ifdef NS_CACHING
 615         nss_cache_data   cache_data;
 616         nss_cache_data  *cache_data_p;
 617         int              cache_flag;
 618 #endif
 619
 620         dbt = NULL;
 621         fb_method = NULL;
 622
 623         isthreaded = __isthreaded;
 624         serrno = errno;
 625         if (isthreaded) {
 626                 result = _pthread_rwlock_rdlock(&nss_lock);
 627                 if (result != 0) {
 628                         result = NS_UNAVAIL;
 629                         goto fin;
 630                 }
 631         }
 632         result = nss_configure();
 633         if (result != 0) {
 634                 result = NS_UNAVAIL;
 635                 goto fin;
 636         }
 637         if (fallback_dispatch == 0) {
 638                 dbt = vector_search(&database, _nsmap, _nsmapsize, sizeof(*_nsmap),
 639                     string_compare);
 640                 fb_method = nss_method_lookup(NSSRC_FALLBACK, database,
 641                     method_name, disp_tab, &mdata);
 642         }
 643
 644         if (dbt != NULL) {
 645                 srclist = dbt->srclist;
 646                 srclistsize = dbt->srclistsize;
 647         } else {
 648                 srclist = defaults;
 649                 srclistsize = 0;
 650                 while (srclist[srclistsize].name != NULL)
 651                         srclistsize++;
 652         }
 653
 654 #ifdef NS_CACHING
 655         cache_data_p = NULL;
 656         cache_flag = 0;
 657 #endif
 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);
 662
 663                 if (method != NULL) {
 664 #ifdef NS_CACHING
 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)
 669                                         continue;
 670 #endif
 671                                 cache_flag = 1;
 672
 673                                 memset(&cache_data, 0, sizeof(nss_cache_data));
 674                                 cache_data.info = (nss_cache_info const *)mdata;
 675                                 cache_data_p = &cache_data;
 676
 677                                 va_start(ap, defaults);
 678                                 if (cache_data.info->id_func != NULL)
 679                                         result = __nss_common_cache_read(retval,
 680                                             cache_data_p, ap);
 681                                 else if (cache_data.info->marshal_func != NULL)
 682                                         result = __nss_mp_cache_read(retval,
 683                                             cache_data_p, ap);
 684                                 else
 685                                         result = __nss_mp_cache_end(retval,
 686                                             cache_data_p, ap);
 687                                 va_end(ap);
 688                         } else {
 689                                 cache_flag = 0;
 690                                 va_start(ap, defaults);
 691                                 result = method(retval, mdata, ap);
 692                                 va_end(ap);
 693                         }
 694 #else /* NS_CACHING */
 695                         va_start(ap, defaults);
 696                         result = method(retval, mdata, ap);
 697                         va_end(ap);
 698 #endif /* NS_CACHING */
 699
 700                         if (result & (srclist[i].flags))
 701                                 break;
 702                 } else {
 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);
 708                                 va_end(ap);
 709                                 fallback_dispatch = 0;
 710                         } else
 711                                 nss_log(LOG_DEBUG, "%s, %s, %s, not found, "
 712                                     "and no fallback provided",
 713                                     srclist[i].name, database, method_name);
 714                 }
 715         }
 716
 717 #ifdef NS_CACHING
 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,
 724                                     ap);
 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,
 731                                             cache_data_p, ap);
 732                         } else
 733                                 __nss_common_cache_write_negative(cache_data_p);
 734                 }
 735                 va_end(ap);
 736         }
 737 #endif /* NS_CACHING */
 738
 739         if (isthreaded)
 740                 _pthread_rwlock_unlock(&nss_lock);
 741 fin:
 742         errno = serrno;
 743         return (result);
 744 }