text: /*	$NetBSD: nsdispatch.c,v 1.9 1999/01/25 00:16:17 lukem Exp $	*/
  
  /*-
   * Copyright (c) 1997, 1998, 1999 The NetBSD Foundation, Inc.
   * All rights reserved.
   *
   * This code is derived from software contributed to The NetBSD Foundation
   * by Luke Mewburn.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. All advertising materials mentioning features or use of this software
   *    must display the following acknowledgement:
   *        This product includes software developed by the NetBSD
   *        Foundation, Inc. and its contributors.
   * 4. Neither the name of The NetBSD Foundation nor the names of its
   *    contributors may be used to endorse or promote products derived
   *    from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
   * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
   * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
   * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   */
  /*-
   * Copyright (c) 2003 Networks Associates Technology, Inc.
   * All rights reserved.
   *
   * Portions of this software were developed for the FreeBSD Project by
   * Jacques A. Vidrine, Safeport Network Services, and Network
   * Associates Laboratories, the Security Research Division of Network
   * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035
   * ("CBOSS"), as part of the DARPA CHATS research program.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   * $FreeBSD: src/lib/libc/net/nsdispatch.c,v 1.17 2008/05/02 14:51:22 jhb Exp $
   */
  
  #include "namespace.h"
  #include <sys/param.h>
  #include <sys/stat.h>
  
  #include <dlfcn.h>
  #include <errno.h>
  #include <fcntl.h>
  #define _NS_PRIVATE
  #include <nsswitch.h>
  #include <pthread.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <syslog.h>
  #include <unistd.h>
  #include "un-namespace.h"
  #include "libc_private.h"
  #ifdef NS_CACHING
  #include "nscache.h"
  #endif
  
  enum _nss_constants {
  	/* Number of elements allocated when we grow a vector */
  	ELEMSPERCHUNK =	8
  };
  
  /*
   * Global NSS data structures are mostly read-only, but we update
   * them when we read or re-read the nsswitch.conf.
   */
  static	pthread_rwlock_t	nss_lock = PTHREAD_RWLOCK_INITIALIZER;
  
  /*
   * Runtime determination of whether we are dynamically linked or not.
   */
  extern	int		_DYNAMIC __attribute__ ((weak));
  #define	is_dynamic()	(&_DYNAMIC != NULL)
  
  /*
   * default sourcelist: `files'
   */
  const ns_src __nsdefaultsrc[] = {
  	{ NSSRC_FILES, NS_SUCCESS },
  	{ 0 },
  };
  
  /* Database, source mappings. */
  static	unsigned int		 _nsmapsize;
  static	ns_dbt			*_nsmap = NULL;
  
  /* NSS modules. */
  static	unsigned int		 _nsmodsize;
  static	ns_mod			*_nsmod;
  
  /* Placeholder for builtin modules' dlopen `handle'. */
  static	int			 __nss_builtin_handle;
  static	void			*nss_builtin_handle = &__nss_builtin_handle;
  
  #ifdef NS_CACHING
  /*
   * Cache lookup cycle prevention function - if !NULL then no cache lookups
   * will be made
   */
  static	void			*nss_cache_cycle_prevention_func = NULL;
  #endif
  
  /*
   * When this is set to 1, nsdispatch won't use nsswitch.conf
   * but will consult the 'defaults' source list only.
   * NOTE: nested fallbacks (when nsdispatch calls fallback functions,
   *     which in turn calls nsdispatch, which should call fallback
   *     function) are not supported
   */
  static	int			fallback_dispatch = 0;
  
  /*
   * Attempt to spew relatively uniform messages to syslog.
   */
  #define nss_log(level, fmt, ...) \
  	syslog((level), "NSSWITCH(%s): " fmt, __func__, __VA_ARGS__)
  #define nss_log_simple(level, s) \
  	syslog((level), "NSSWITCH(%s): " s, __func__)
  
  /*
   * Dynamically growable arrays are used for lists of databases, sources,
   * and modules.  The following `vector' interface is used to isolate the
   * common operations.
   */
  typedef	int	(*vector_comparison)(const void *, const void *);
  typedef	void	(*vector_free_elem)(void *);
  static	void	  vector_sort(void *, unsigned int, size_t,
  		    vector_comparison);
  static	void	  vector_free(void *, unsigned int *, size_t,
  		    vector_free_elem);
  static	void	 *vector_ref(unsigned int, void *, unsigned int, size_t);
  static	void	 *vector_search(const void *, void *, unsigned int, size_t,
  		    vector_comparison);
  static	void	 *vector_append(const void *, void *, unsigned int *, size_t);
  
  
  /*
   * Internal interfaces.
   */
  static	int	 string_compare(const void *, const void *);
  static	int	 mtab_compare(const void *, const void *);
  static	int	 nss_configure(void);
  static	void	 ns_dbt_free(ns_dbt *);
  static	void	 ns_mod_free(ns_mod *);
  static	void	 ns_src_free(ns_src **, int);
  static	void	 nss_load_builtin_modules(void);
  static	void	 nss_load_module(const char *, nss_module_register_fn);
  static	void	 nss_atexit(void);
  /* nsparser */
  extern	FILE	*_nsyyin;
  
  
  /*
   * The vector operations
   */
  static void
  vector_sort(void *vec, unsigned int count, size_t esize,
      vector_comparison comparison)
  {
  	qsort(vec, count, esize, comparison);
  }
  
  
  static void *
  vector_search(const void *key, void *vec, unsigned int count, size_t esize,
      vector_comparison comparison)
  {
  	return (bsearch(key, vec, count, esize, comparison));
  }
  
  
  static void *
  vector_append(const void *elem, void *vec, unsigned int *count, size_t esize)
  {
  	void	*p;
  
  	if ((*count % ELEMSPERCHUNK) == 0) {
  		p = realloc(vec, (*count + ELEMSPERCHUNK) * esize);
  		if (p == NULL) {
  			nss_log_simple(LOG_ERR, "memory allocation failure");
  			return (vec);
  		}
  		vec = p;
  	}
  	memmove((void *)(((uintptr_t)vec) + (*count * esize)), elem, esize);
  	(*count)++;
  	return (vec);
  }
  
  
  static void *
  vector_ref(unsigned int i, void *vec, unsigned int count, size_t esize)
  {
  	if (i < count)
  		return (void *)((uintptr_t)vec + (i * esize));
  	else
  		return (NULL);
  }
  
  
  #define VECTOR_FREE(v, c, s, f) \
  	do { vector_free(v, c, s, f); v = NULL; } while (0)
  static void
  vector_free(void *vec, unsigned int *count, size_t esize,
      vector_free_elem free_elem)
  {
  	unsigned int	 i;
  	void		*elem;
  
  	for (i = 0; i < *count; i++) {
  		elem = vector_ref(i, vec, *count, esize);
  		if (elem != NULL)
  			free_elem(elem);
  	}
  	free(vec);
  	*count = 0;
  }
  
  /*
   * Comparison functions for vector_search.
   */
  static int
  string_compare(const void *a, const void *b)
  {
        return (strcasecmp(*(const char * const *)a, *(const char * const *)b));
  }
  
  
  static int
  mtab_compare(const void *a, const void *b)
  {
        int     cmp;
  
        cmp = strcmp(((const ns_mtab *)a)->name, ((const ns_mtab *)b)->name);
        if (cmp != 0)
  	      return (cmp);
        else
  	      return (strcmp(((const ns_mtab *)a)->database,
  		  ((const ns_mtab *)b)->database));
  }
  
  /*
   * NSS nsmap management.
   */
  void
  _nsdbtaddsrc(ns_dbt *dbt, const ns_src *src)
  {
  	const ns_mod	*modp;
  
  	dbt->srclist = vector_append(src, dbt->srclist, &dbt->srclistsize,
  	    sizeof(*src));
  	modp = vector_search(&src->name, _nsmod, _nsmodsize, sizeof(*_nsmod),
  	    string_compare);
  	if (modp == NULL)
  		nss_load_module(src->name, NULL);
  }
  
  
  #ifdef _NSS_DEBUG
  void
  _nsdbtdump(const ns_dbt *dbt)
  {
  	int i;
  
  	printf("%s (%d source%s):", dbt->name, dbt->srclistsize,
  	    dbt->srclistsize == 1 ? "" : "s");
  	for (i = 0; i < (int)dbt->srclistsize; i++) {
  		printf(" %s", dbt->srclist[i].name);
  		if (!(dbt->srclist[i].flags &
  		    (NS_UNAVAIL|NS_NOTFOUND|NS_TRYAGAIN)) &&
  		    (dbt->srclist[i].flags & NS_SUCCESS))
  			continue;
  		printf(" [");
  		if (!(dbt->srclist[i].flags & NS_SUCCESS))
  			printf(" SUCCESS=continue");
  		if (dbt->srclist[i].flags & NS_UNAVAIL)
  			printf(" UNAVAIL=return");
  		if (dbt->srclist[i].flags & NS_NOTFOUND)
  			printf(" NOTFOUND=return");
  		if (dbt->srclist[i].flags & NS_TRYAGAIN)
  			printf(" TRYAGAIN=return");
  		printf(" ]");
  	}
  	printf("\n");
  }
  #endif
  
  
  /*
   * The first time nsdispatch is called (during a process's lifetime,
   * or after nsswitch.conf has been updated), nss_configure will
   * prepare global data needed by NSS.
   */
  static int
  nss_configure(void)
  {
  	static pthread_mutex_t conf_lock = PTHREAD_MUTEX_INITIALIZER;
  	static time_t	 confmod;
  	struct stat	 statbuf;
  	int		 result, isthreaded;
  	const char	*path;
  #ifdef NS_CACHING
  	void		*handle;
  #endif
  
  	result = 0;
  	isthreaded = __isthreaded;
  #if defined(_NSS_DEBUG) && defined(_NSS_SHOOT_FOOT)
  	/* NOTE WELL:  THIS IS A SECURITY HOLE. This must only be built
  	 * for debugging purposes and MUST NEVER be used in production.
  	 */
  	path = getenv("NSSWITCH_CONF");
  	if (path == NULL)
  #endif
  	path = _PATH_NS_CONF;
  	if (stat(path, &statbuf) != 0)
  		return (0);
  	if (statbuf.st_mtime <= confmod)
  		return (0);
  	if (isthreaded) {
  	    result = _pthread_mutex_trylock(&conf_lock);
  	    if (result != 0)
  		    return (0);
  	    _pthread_rwlock_unlock(&nss_lock);
  	    result = _pthread_rwlock_wrlock(&nss_lock);
  	    if (result != 0)
  		    goto fin2;
  	}
  	_nsyyin = fopen(path, "r");
  	if (_nsyyin == NULL)
  		goto fin;
  	VECTOR_FREE(_nsmap, &_nsmapsize, sizeof(*_nsmap),
  	    (vector_free_elem)ns_dbt_free);
  	VECTOR_FREE(_nsmod, &_nsmodsize, sizeof(*_nsmod),
  	    (vector_free_elem)ns_mod_free);
  	nss_load_builtin_modules();
  	_nsyyparse();
  	fclose(_nsyyin);
  	vector_sort(_nsmap, _nsmapsize, sizeof(*_nsmap), string_compare);
  	if (confmod == 0)
  		atexit(nss_atexit);
  	confmod = statbuf.st_mtime;
  
  #ifdef NS_CACHING
  	handle = dlopen(NULL, RTLD_LAZY | RTLD_GLOBAL);
  	if (handle != NULL) {
  		nss_cache_cycle_prevention_func = dlsym(handle,
  			"_nss_cache_cycle_prevention_function");
  		dlclose(handle);
  	}
  #endif
  fin:
  	if (isthreaded) {
  	    _pthread_rwlock_unlock(&nss_lock);
  	    if (result == 0)
  		    result = _pthread_rwlock_rdlock(&nss_lock);
  	}
  fin2:
  	if (isthreaded)
  		_pthread_mutex_unlock(&conf_lock);
  	return (result);
  }
  
  
  void
  _nsdbtput(const ns_dbt *dbt)
  {
  	unsigned int	 i;
  	ns_dbt		*p;
  
  	for (i = 0; i < _nsmapsize; i++) {
  		p = vector_ref(i, _nsmap, _nsmapsize, sizeof(*_nsmap));
  		if (string_compare(&dbt->name, &p->name) == 0) {
  			/* overwrite existing entry */
  			if (p->srclist != NULL)
  				ns_src_free(&p->srclist, p->srclistsize);
  			memmove(p, dbt, sizeof(*dbt));
  			return;
  		}
  	}
  	_nsmap = vector_append(dbt, _nsmap, &_nsmapsize, sizeof(*_nsmap));
  }
  
  
  static void
  ns_dbt_free(ns_dbt *dbt)
  {
  	ns_src_free(&dbt->srclist, dbt->srclistsize);
  	if (dbt->name)
  		free((void *)dbt->name);
  }
  
  
  static void
  ns_src_free(ns_src **src, int srclistsize)
  {
  	int	i;
  
  	for (i = 0; i < srclistsize; i++)
  		if ((*src)[i].name != NULL)
  			/* This one was allocated by nslexer. You'll just
  			 * have to trust me.
  			 */
  			free((void *)((*src)[i].name));
  	free(*src);
  	*src = NULL;
  }
  
  
  
  /*
   * NSS module management.
   */
  /* The built-in NSS modules are all loaded at once. */
  #define NSS_BACKEND(name, reg) \
  ns_mtab	*reg(unsigned int *, nss_module_unregister_fn *);
  #include "nss_backends.h"
  #undef NSS_BACKEND
  
  static void
  nss_load_builtin_modules(void)
  {
  #define NSS_BACKEND(name, reg) nss_load_module(#name, reg);
  #include "nss_backends.h"
  #undef NSS_BACKEND
  }
  
  
  /* Load a built-in or dynamically linked module.  If the `reg_fn'
   * argument is non-NULL, assume a built-in module and use reg_fn to
   * register it.  Otherwise, search for a dynamic NSS module.
   */
  static void
  nss_load_module(const char *source, nss_module_register_fn reg_fn)
  {
  	char		 buf[PATH_MAX];
  	ns_mod		 mod;
  	nss_module_register_fn fn;
  
  	memset(&mod, 0, sizeof(mod));
  	mod.name = strdup(source);
  	if (mod.name == NULL) {
  		nss_log_simple(LOG_ERR, "memory allocation failure");
  		return;
  	}
  	if (reg_fn != NULL) {
  		/* The placeholder is required, as a NULL handle
  		 * represents an invalid module.
  		 */
  		mod.handle = nss_builtin_handle;
  		fn = reg_fn;
  	} else if (!is_dynamic())
  		goto fin;
  	else {
  		if (snprintf(buf, sizeof(buf), "nss_%s.so.%d", mod.name,
  		    NSS_MODULE_INTERFACE_VERSION) >= (int)sizeof(buf))
  			goto fin;
  		mod.handle = dlopen(buf, RTLD_LOCAL|RTLD_LAZY);
  		if (mod.handle == NULL) {
  #ifdef _NSS_DEBUG
  			/* This gets pretty annoying since the built-in
  			 * sources aren't modules yet.
  			 */
  			nss_log(LOG_DEBUG, "%s, %s", mod.name, dlerror());
  #endif
  			goto fin;
  		}
  		fn = (nss_module_register_fn)dlfunc(mod.handle,
  		    "nss_module_register");
  		if (fn == NULL) {
  			dlclose(mod.handle);
  			mod.handle = NULL;
  			nss_log(LOG_ERR, "%s, %s", mod.name, dlerror());
  			goto fin;
  		}
  	}
  	mod.mtab = fn(mod.name, &mod.mtabsize, &mod.unregister);
  	if (mod.mtab == NULL || mod.mtabsize == 0) {
  		if (mod.handle != nss_builtin_handle)
  			dlclose(mod.handle);
  		mod.handle = NULL;
  		nss_log(LOG_ERR, "%s, registration failed", mod.name);
  		goto fin;
  	}
  	if (mod.mtabsize > 1)
  		qsort(mod.mtab, mod.mtabsize, sizeof(mod.mtab[0]),
  		    mtab_compare);
  fin:
  	_nsmod = vector_append(&mod, _nsmod, &_nsmodsize, sizeof(*_nsmod));
  	vector_sort(_nsmod, _nsmodsize, sizeof(*_nsmod), string_compare);
  }
  
  
  
  static void
  ns_mod_free(ns_mod *mod)
  {
  
  	free(mod->name);
  	if (mod->handle == NULL)
  		return;
  	if (mod->unregister != NULL)
  		mod->unregister(mod->mtab, mod->mtabsize);
  	if (mod->handle != nss_builtin_handle)
  		dlclose(mod->handle);
  }
  
  
  
  /*
   * Cleanup
   */
  static void
  nss_atexit(void)
  {
  	int isthreaded;
  
  	isthreaded = __isthreaded;
  	if (isthreaded)
  		_pthread_rwlock_wrlock(&nss_lock);
  	VECTOR_FREE(_nsmap, &_nsmapsize, sizeof(*_nsmap),
  	    (vector_free_elem)ns_dbt_free);
  	VECTOR_FREE(_nsmod, &_nsmodsize, sizeof(*_nsmod),
  	    (vector_free_elem)ns_mod_free);
  	if (isthreaded)
  		_pthread_rwlock_unlock(&nss_lock);
  }
  
  
  
  /*
   * Finally, the actual implementation.
   */
  static nss_method
  nss_method_lookup(const char *source, const char *database,
      const char *method, const ns_dtab disp_tab[], void **mdata)
  {
  	ns_mod	*mod;
  	ns_mtab	*match, key;
  	int	 i;
  
  	if (disp_tab != NULL)
  		for (i = 0; disp_tab[i].src != NULL; i++)
  			if (strcasecmp(source, disp_tab[i].src) == 0) {
  				*mdata = disp_tab[i].mdata;
  				return (disp_tab[i].method);
  			}
  	mod = vector_search(&source, _nsmod, _nsmodsize, sizeof(*_nsmod),
  	    string_compare);
  	if (mod != NULL && mod->handle != NULL) {
  		key.database = database;
  		key.name = method;
  		match = bsearch(&key, mod->mtab, mod->mtabsize,
  		    sizeof(mod->mtab[0]), mtab_compare);
  		if (match != NULL) {
  			*mdata = match->mdata;
  			return (match->method);
  		}
  	}
  
  	*mdata = NULL;
  	return (NULL);
  }
  
  
  __weak_reference(_nsdispatch, nsdispatch);
  
  int
  _nsdispatch(void *retval, const ns_dtab disp_tab[], const char *database,
  	    const char *method_name, const ns_src defaults[], ...)
  {
  	va_list		 ap;
  	const ns_dbt	*dbt;
  	const ns_src	*srclist;
  	nss_method	 method, fb_method;
  	void		*mdata;
  	int		 isthreaded, serrno, i, result, srclistsize;
  
  #ifdef NS_CACHING
  	nss_cache_data	 cache_data;
  	nss_cache_data	*cache_data_p;
  	int		 cache_flag;
  #endif
  
  	dbt = NULL;
  	fb_method = NULL;
  
  	isthreaded = __isthreaded;
  	serrno = errno;
  	if (isthreaded) {
  		result = _pthread_rwlock_rdlock(&nss_lock);
  		if (result != 0) {
  			result = NS_UNAVAIL;
  			goto fin;
  		}
  	}
  	result = nss_configure();
  	if (result != 0) {
  		result = NS_UNAVAIL;
  		goto fin;
  	}
  	if (fallback_dispatch == 0) {
  		dbt = vector_search(&database, _nsmap, _nsmapsize, sizeof(*_nsmap),
  		    string_compare);
  		fb_method = nss_method_lookup(NSSRC_FALLBACK, database,
  		    method_name, disp_tab, &mdata);
  	}
  
  	if (dbt != NULL) {
  		srclist = dbt->srclist;
  		srclistsize = dbt->srclistsize;
  	} else {
  		srclist = defaults;
  		srclistsize = 0;
  		while (srclist[srclistsize].name != NULL)
  			srclistsize++;
  	}
  
  #ifdef NS_CACHING
  	cache_data_p = NULL;
  	cache_flag = 0;
  #endif
  	for (i = 0; i < srclistsize; i++) {
  		result = NS_NOTFOUND;
  		method = nss_method_lookup(srclist[i].name, database,
  		    method_name, disp_tab, &mdata);
  
  		if (method != NULL) {
  #ifdef NS_CACHING
  			if (strcmp(srclist[i].name, NSSRC_CACHE) == 0 &&
  			    nss_cache_cycle_prevention_func == NULL) {
  #ifdef NS_STRICT_LIBC_EID_CHECKING
  				if (issetugid() != 0)
  					continue;
  #endif
  				cache_flag = 1;
  
  				memset(&cache_data, 0, sizeof(nss_cache_data));
  				cache_data.info = (nss_cache_info const *)mdata;
  				cache_data_p = &cache_data;
  
  				va_start(ap, defaults);
  				if (cache_data.info->id_func != NULL)
  					result = __nss_common_cache_read(retval,
  					    cache_data_p, ap);
  				else if (cache_data.info->marshal_func != NULL)
  					result = __nss_mp_cache_read(retval,
  					    cache_data_p, ap);
  				else
  					result = __nss_mp_cache_end(retval,
  					    cache_data_p, ap);
  				va_end(ap);
  			} else {
  				cache_flag = 0;
  				va_start(ap, defaults);
  				result = method(retval, mdata, ap);
  				va_end(ap);
  			}
  #else /* NS_CACHING */
  			va_start(ap, defaults);
  			result = method(retval, mdata, ap);
  			va_end(ap);
  #endif /* NS_CACHING */
  
  			if (result & (srclist[i].flags))
  				break;
  		} else {
  			if (fb_method != NULL) {
  				fallback_dispatch = 1;
  				va_start(ap, defaults);
  				result = fb_method(retval,
  				    (void *)srclist[i].name, ap);
  				va_end(ap);
  				fallback_dispatch = 0;
  			} else
  				nss_log(LOG_DEBUG, "%s, %s, %s, not found, "
  				    "and no fallback provided",
  				    srclist[i].name, database, method_name);
  		}
  	}
  
  #ifdef NS_CACHING
  	if (cache_data_p != NULL &&
  	    (result & (NS_NOTFOUND | NS_SUCCESS)) && cache_flag == 0) {
  		va_start(ap, defaults);
  		if (result == NS_SUCCESS) {
  			if (cache_data.info->id_func != NULL)
  				__nss_common_cache_write(retval, cache_data_p,
  				    ap);
  			else if (cache_data.info->marshal_func != NULL)
  				__nss_mp_cache_write(retval, cache_data_p, ap);
  		} else if (result == NS_NOTFOUND) {
  			if (cache_data.info->id_func == NULL) {
  				if (cache_data.info->marshal_func != NULL)
  					__nss_mp_cache_write_submit(retval,
  					    cache_data_p, ap);
  			} else
  				__nss_common_cache_write_negative(cache_data_p);
  		}
  		va_end(ap);
  	}
  #endif /* NS_CACHING */
  
  	if (isthreaded)
  		_pthread_rwlock_unlock(&nss_lock);
  fin:
  	errno = serrno;
  	return (result);
  }
  