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Generalize framework to register monitoring of files in nscd
nscd can clear caches when certain files change. The list of files was hardcoded so far and worked for nss_files and nss_dns and those modules which need no monitoring. nss_db, for instance, has its own set of files to monitor. Now the NSS modules themselves can request that certain files are monitored.
This commit is contained in:
Ulrich Drepper
165
nss/nsswitch.c
165
nss/nsswitch.c
@ -1,4 +1,5 @@
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/* Copyright (C) 1996-1999,2001-2007,2009,2010 Free Software Foundation, Inc.
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/* Copyright (C) 1996-1999,2001-2007,2009,2010,2011
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Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
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@ -40,6 +41,7 @@
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#include "nsswitch.h"
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#include "../nscd/nscd_proto.h"
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#include <sysdep.h>
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/* Prototypes for the local functions. */
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static name_database *nss_parse_file (const char *fname) internal_function;
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@ -86,6 +88,12 @@ static const char *const __nss_shlib_revision = LIBNSS_FILES_SO + 15;
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static name_database *service_table;
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/* Nonzero if this is the nscd process. */
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static bool is_nscd;
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/* The callback passed to the init functions when nscd is used. */
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static void (*nscd_init_cb) (size_t, struct traced_file *);
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/* -1 == database not found
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0 == database entry pointer stored */
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int
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@ -129,7 +137,7 @@ __nss_database_lookup (const char *database, const char *alternate_name,
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}
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/* No configuration data is available, either because nsswitch.conf
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doesn't exist or because it doesn't has a line for this database.
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doesn't exist or because it doesn't have a line for this database.
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DEFCONFIG specifies the default service list for this database,
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or null to use the most common default. */
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@ -285,6 +293,79 @@ known_compare (const void *p1, const void *p2)
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}
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#if !defined DO_STATIC_NSS || defined SHARED
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/* Load library. */
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static int
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nss_load_library (service_user *ni)
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{
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if (ni->library == NULL)
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{
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/* This service has not yet been used. Fetch the service
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library for it, creating a new one if need be. If there
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is no service table from the file, this static variable
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holds the head of the service_library list made from the
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default configuration. */
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static name_database default_table;
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ni->library = nss_new_service (service_table ?: &default_table,
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ni->name);
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if (ni->library == NULL)
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return -1;
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}
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if (ni->library->lib_handle == NULL)
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{
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/* Load the shared library. */
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size_t shlen = (7 + strlen (ni->library->name) + 3
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+ strlen (__nss_shlib_revision) + 1);
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int saved_errno = errno;
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char shlib_name[shlen];
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/* Construct shared object name. */
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__stpcpy (__stpcpy (__stpcpy (__stpcpy (shlib_name,
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"libnss_"),
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ni->library->name),
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".so"),
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__nss_shlib_revision);
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ni->library->lib_handle = __libc_dlopen (shlib_name);
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if (ni->library->lib_handle == NULL)
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{
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/* Failed to load the library. */
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ni->library->lib_handle = (void *) -1l;
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__set_errno (saved_errno);
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}
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else if (is_nscd)
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{
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/* Call the init function when nscd is used. */
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size_t initlen = (5 + strlen (ni->library->name)
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+ strlen ("_init") + 1);
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char init_name[initlen];
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/* Construct the init function name. */
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__stpcpy (__stpcpy (__stpcpy (init_name,
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"_nss_"),
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ni->library->name),
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"_init");
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/* Find the optional init function. */
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void (*ifct) (void (*) (size_t, struct traced_file *))
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= __libc_dlsym (ni->library->lib_handle, init_name);
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if (ifct != NULL)
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{
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void (*cb) (size_t, struct traced_file *) = nscd_init_cb;
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# ifdef PTR_DEMANGLE
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PTR_DEMANGLE (cb);
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# endif
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ifct (cb);
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}
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}
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}
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return 0;
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}
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#endif
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void *
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__nss_lookup_function (service_user *ni, const char *fct_name)
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{
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@ -331,47 +412,13 @@ __nss_lookup_function (service_user *ni, const char *fct_name)
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*found = known;
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known->fct_name = fct_name;
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if (ni->library == NULL)
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{
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/* This service has not yet been used. Fetch the service
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library for it, creating a new one if need be. If there
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is no service table from the file, this static variable
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holds the head of the service_library list made from the
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default configuration. */
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static name_database default_table;
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ni->library = nss_new_service (service_table ?: &default_table,
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ni->name);
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if (ni->library == NULL)
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{
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/* This only happens when out of memory. */
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free (known);
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goto remove_from_tree;
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}
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}
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#if !defined DO_STATIC_NSS || defined SHARED
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if (ni->library->lib_handle == NULL)
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/* Load the appropriate library. */
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if (nss_load_library (ni) != 0)
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{
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/* Load the shared library. */
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size_t shlen = (7 + strlen (ni->library->name) + 3
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+ strlen (__nss_shlib_revision) + 1);
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int saved_errno = errno;
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char shlib_name[shlen];
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/* Construct shared object name. */
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__stpcpy (__stpcpy (__stpcpy (__stpcpy (shlib_name,
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"libnss_"),
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ni->library->name),
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".so"),
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__nss_shlib_revision);
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ni->library->lib_handle = __libc_dlopen (shlib_name);
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if (ni->library->lib_handle == NULL)
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{
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/* Failed to load the library. */
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ni->library->lib_handle = (void *) -1l;
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__set_errno (saved_errno);
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}
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/* This only happens when out of memory. */
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free (known);
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goto remove_from_tree;
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}
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if (ni->library->lib_handle == (void *) -1l)
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@ -463,7 +510,10 @@ nss_parse_file (const char *fname)
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result = (name_database *) malloc (sizeof (name_database));
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if (result == NULL)
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return NULL;
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{
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fclose (fp);
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return NULL;
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}
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result->entry = NULL;
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result->library = NULL;
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@ -724,16 +774,45 @@ nss_new_service (name_database *database, const char *name)
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}
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#ifdef SHARED
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/* Load all libraries for the service. */
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static void
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nss_load_all_libraries (const char *service, const char *def)
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{
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service_user *ni = NULL;
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if (__nss_database_lookup (service, NULL, def, &ni) == 0)
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while (ni != NULL)
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{
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nss_load_library (ni);
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ni = ni->next;
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}
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}
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/* Called by nscd and nscd alone. */
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void
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__nss_disable_nscd (void)
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__nss_disable_nscd (void (*cb) (size_t, struct traced_file *))
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{
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# ifdef PTR_MANGLE
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PTR_MANGLE (cb);
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# endif
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nscd_init_cb = cb;
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is_nscd = true;
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/* Find all the relevant modules so that the init functions are called. */
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nss_load_all_libraries ("passwd", "compat [NOTFOUND=return] files");
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nss_load_all_libraries ("group", "compat [NOTFOUND=return] files");
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nss_load_all_libraries ("hosts", "dns [!UNAVAIL=return] files");
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nss_load_all_libraries ("services", NULL);
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/* Disable all uses of NSCD. */
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__nss_not_use_nscd_passwd = -1;
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__nss_not_use_nscd_group = -1;
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__nss_not_use_nscd_hosts = -1;
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__nss_not_use_nscd_services = -1;
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}
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#endif
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/* Free all resources if necessary. */
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