nss/nsswitch.c

   1 /* Copyright (C) 1996-1999, 2001-2007, 2009 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <ctype.h>
  21 #include <dlfcn.h>
  22 #include <errno.h>
  23 #include <netdb.h>
  24 #include <bits/libc-lock.h>
  25 #include <search.h>
  26 #include <stdio.h>
  27 #include <stdio_ext.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30
  31 #include <aliases.h>
  32 #include <grp.h>
  33 #include <netinet/ether.h>
  34 #include <pwd.h>
  35 #include <shadow.h>
  36
  37 #if !defined DO_STATIC_NSS || defined SHARED
  38 # include <gnu/lib-names.h>
  39 #endif
  40
  41 #include "nsswitch.h"
  42 #include "../nscd/nscd_proto.h"
  43
  44 /* Prototypes for the local functions.  */
  45 static name_database *nss_parse_file (const char *fname) internal_function;
  46 static name_database_entry *nss_getline (char *line) internal_function;
  47 static service_user *nss_parse_service_list (const char *line)
  48      internal_function;
  49 static service_library *nss_new_service (name_database *database,
  50                                          const char *name) internal_function;
  51
  52
  53 /* Declare external database variables.  */
  54 #define DEFINE_DATABASE(name)                                                 \
  55   extern service_user *__nss_##name##_database attribute_hidden;              \
  56   weak_extern (__nss_##name##_database)
  57 #include "databases.def"
  58 #undef DEFINE_DATABASE
  59
  60 /* Structure to map database name to variable.  */
  61 static const struct
  62 {
  63   const char name[10];
  64   service_user **dbp;
  65 } databases[] =
  66 {
  67 #define DEFINE_DATABASE(name)                                                 \
  68   { #name, &__nss_##name##_database },
  69 #include "databases.def"
  70 #undef DEFINE_DATABASE
  71 };
  72 #define ndatabases (sizeof (databases) / sizeof (databases[0]))
  73
  74
  75 __libc_lock_define_initialized (static, lock)
  76
  77 #if !defined DO_STATIC_NSS || defined SHARED
  78 /* String with revision number of the shared object files.  */
  79 static const char *const __nss_shlib_revision = LIBNSS_FILES_SO + 15;
  80 #endif
  81
  82 /* The root of the whole data base.  */
  83 static name_database *service_table;
  84
  85
  86 /* -1 == database not found
  87     0 == database entry pointer stored */
  88 int
  89 __nss_database_lookup (const char *database, const char *alternate_name,
  90                        const char *defconfig, service_user **ni)
  91 {
  92   /* Prevent multiple threads to change the service table.  */
  93   __libc_lock_lock (lock);
  94
  95   /* Reconsider database variable in case some other thread called
  96      `__nss_configure_lookup' while we waited for the lock.  */
  97   if (*ni != NULL)
  98     {
  99       __libc_lock_unlock (lock);
 100       return 0;
 101     }
 102
 103   /* Are we initialized yet?  */
 104   if (service_table == NULL)
 105     /* Read config file.  */
 106     service_table = nss_parse_file (_PATH_NSSWITCH_CONF);
 107
 108   /* Test whether configuration data is available.  */
 109   if (service_table != NULL)
 110     {
 111       /* Return first `service_user' entry for DATABASE.  */
 112       name_database_entry *entry;
 113
 114       /* XXX Could use some faster mechanism here.  But each database is
 115          only requested once and so this might not be critical.  */
 116       for (entry = service_table->entry; entry != NULL; entry = entry->next)
 117         if (strcmp (database, entry->name) == 0)
 118           *ni = entry->service;
 119
 120       if (*ni == NULL && alternate_name != NULL)
 121         /* We haven't found an entry so far.  Try to find it with the
 122            alternative name.  */
 123         for (entry = service_table->entry; entry != NULL; entry = entry->next)
 124           if (strcmp (alternate_name, entry->name) == 0)
 125             *ni = entry->service;
 126     }
 127
 128   /* No configuration data is available, either because nsswitch.conf
 129      doesn't exist or because it doesn't has a line for this database.
 130
 131      DEFCONFIG specifies the default service list for this database,
 132      or null to use the most common default.  */
 133   if (*ni == NULL)
 134     *ni = nss_parse_service_list (defconfig
 135                                   ?: "nis [NOTFOUND=return] files");
 136
 137   __libc_lock_unlock (lock);
 138
 139   return 0;
 140 }
 141 libc_hidden_def (__nss_database_lookup)
 142
 143
 144 /* -1 == not found
 145     0 == function found
 146     1 == finished */
 147 int
 148 __nss_lookup (service_user **ni, const char *fct_name, const char *fct2_name,
 149               void **fctp)
 150 {
 151   *fctp = __nss_lookup_function (*ni, fct_name);
 152   if (*fctp == NULL && fct2_name != NULL)
 153     *fctp = __nss_lookup_function (*ni, fct2_name);
 154
 155   while (*fctp == NULL
 156          && nss_next_action (*ni, NSS_STATUS_UNAVAIL) == NSS_ACTION_CONTINUE
 157          && (*ni)->next != NULL)
 158     {
 159       *ni = (*ni)->next;
 160
 161       *fctp = __nss_lookup_function (*ni, fct_name);
 162       if (*fctp == NULL && fct2_name != NULL)
 163         *fctp = __nss_lookup_function (*ni, fct2_name);
 164     }
 165
 166   return *fctp != NULL ? 0 : (*ni)->next == NULL ? 1 : -1;
 167 }
 168
 169
 170 /* -1 == not found
 171     0 == adjusted for next function
 172     1 == finished */
 173 int
 174 __nss_next2 (service_user **ni, const char *fct_name, const char *fct2_name,
 175              void **fctp, int status, int all_values)
 176 {
 177   if (all_values)
 178     {
 179       if (nss_next_action (*ni, NSS_STATUS_TRYAGAIN) == NSS_ACTION_RETURN
 180           && nss_next_action (*ni, NSS_STATUS_UNAVAIL) == NSS_ACTION_RETURN
 181           && nss_next_action (*ni, NSS_STATUS_NOTFOUND) == NSS_ACTION_RETURN
 182           && nss_next_action (*ni, NSS_STATUS_SUCCESS) == NSS_ACTION_RETURN)
 183         return 1;
 184     }
 185   else
 186     {
 187       /* This is really only for debugging.  */
 188       if (__builtin_expect (NSS_STATUS_TRYAGAIN > status
 189                             || status > NSS_STATUS_RETURN, 0))
 190          __libc_fatal ("illegal status in __nss_next");
 191
 192        if (nss_next_action (*ni, status) == NSS_ACTION_RETURN)
 193          return 1;
 194     }
 195
 196   if ((*ni)->next == NULL)
 197     return -1;
 198
 199   do
 200     {
 201       *ni = (*ni)->next;
 202
 203       *fctp = __nss_lookup_function (*ni, fct_name);
 204       if (*fctp == NULL && fct2_name != NULL)
 205         *fctp = __nss_lookup_function (*ni, fct2_name);
 206     }
 207   while (*fctp == NULL
 208          && nss_next_action (*ni, NSS_STATUS_UNAVAIL) == NSS_ACTION_CONTINUE
 209          && (*ni)->next != NULL);
 210
 211   return *fctp != NULL ? 0 : -1;
 212 }
 213 libc_hidden_def (__nss_next2)
 214
 215
 216 int
 217 attribute_compat_text_section
 218 __nss_next (service_user **ni, const char *fct_name, void **fctp, int status,
 219             int all_values)
 220 {
 221   return __nss_next2 (ni, fct_name, NULL, fctp, status, all_values);
 222 }
 223
 224
 225 int
 226 __nss_configure_lookup (const char *dbname, const char *service_line)
 227 {
 228   service_user *new_db;
 229   size_t cnt;
 230
 231   for (cnt = 0; cnt < ndatabases; ++cnt)
 232     {
 233       int cmp = strcmp (dbname, databases[cnt].name);
 234       if (cmp == 0)
 235         break;
 236       if (cmp < 0)
 237         {
 238           __set_errno (EINVAL);
 239           return -1;
 240         }
 241     }
 242
 243   if (cnt == ndatabases)
 244     {
 245       __set_errno (EINVAL);
 246       return -1;
 247     }
 248
 249   /* Test whether it is really used.  */
 250   if (databases[cnt].dbp == NULL)
 251     /* Nothing to do, but we could do.  */
 252     return 0;
 253
 254   /* Try to generate new data.  */
 255   new_db = nss_parse_service_list (service_line);
 256   if (new_db == NULL)
 257     {
 258       /* Illegal service specification.  */
 259       __set_errno (EINVAL);
 260       return -1;
 261     }
 262
 263   /* Prevent multiple threads to change the service table.  */
 264   __libc_lock_lock (lock);
 265
 266   /* Install new rules.  */
 267   *databases[cnt].dbp = new_db;
 268
 269   __libc_lock_unlock (lock);
 270
 271   return 0;
 272 }
 273
 274
 275 /* Comparison function for searching NI->known tree.  */
 276 static int
 277 known_compare (const void *p1, const void *p2)
 278 {
 279   return p1 == p2 ? 0 : strcmp (*(const char *const *) p1,
 280                                 *(const char *const *) p2);
 281 }
 282
 283
 284 void *
 285 __nss_lookup_function (service_user *ni, const char *fct_name)
 286 {
 287   void **found, *result;
 288
 289   /* We now modify global data.  Protect it.  */
 290   __libc_lock_lock (lock);
 291
 292   /* Search the tree of functions previously requested.  Data in the
 293      tree are `known_function' structures, whose first member is a
 294      `const char *', the lookup key.  The search returns a pointer to
 295      the tree node structure; the first member of the is a pointer to
 296      our structure (i.e. what will be a `known_function'); since the
 297      first member of that is the lookup key string, &FCT_NAME is close
 298      enough to a pointer to our structure to use as a lookup key that
 299      will be passed to `known_compare' (above).  */
 300
 301   found = __tsearch (&fct_name, &ni->known, &known_compare);
 302   if (*found != &fct_name)
 303     {
 304       /* The search found an existing structure in the tree.  */
 305       result = ((known_function *) *found)->fct_ptr;
 306       PTR_DEMANGLE (result);
 307     }
 308   else
 309     {
 310       /* This name was not known before.  Now we have a node in the tree
 311          (in the proper sorted position for FCT_NAME) that points to
 312          &FCT_NAME instead of any real `known_function' structure.
 313          Allocate a new structure and fill it in.  */
 314
 315       known_function *known = malloc (sizeof *known);
 316       if (! known)
 317         {
 318         remove_from_tree:
 319           /* Oops.  We can't instantiate this node properly.
 320              Remove it from the tree.  */
 321           __tdelete (&fct_name, &ni->known, &known_compare);
 322           result = NULL;
 323         }
 324       else
 325         {
 326           /* Point the tree node at this new structure.  */
 327           *found = known;
 328           known->fct_name = fct_name;
 329
 330           if (ni->library == NULL)
 331             {
 332               /* This service has not yet been used.  Fetch the service
 333                  library for it, creating a new one if need be.  If there
 334                  is no service table from the file, this static variable
 335                  holds the head of the service_library list made from the
 336                  default configuration.  */
 337               static name_database default_table;
 338               ni->library = nss_new_service (service_table ?: &default_table,
 339                                              ni->name);
 340               if (ni->library == NULL)
 341                 {
 342                   /* This only happens when out of memory.  */
 343                   free (known);
 344                   goto remove_from_tree;
 345                 }
 346             }
 347
 348 #if !defined DO_STATIC_NSS || defined SHARED
 349           if (ni->library->lib_handle == NULL)
 350             {
 351               /* Load the shared library.  */
 352               size_t shlen = (7 + strlen (ni->library->name) + 3
 353                               + strlen (__nss_shlib_revision) + 1);
 354               int saved_errno = errno;
 355               char shlib_name[shlen];
 356
 357               /* Construct shared object name.  */
 358               __stpcpy (__stpcpy (__stpcpy (__stpcpy (shlib_name,
 359                                                       "libnss_"),
 360                                             ni->library->name),
 361                                   ".so"),
 362                         __nss_shlib_revision);
 363
 364               ni->library->lib_handle = __libc_dlopen (shlib_name);
 365               if (ni->library->lib_handle == NULL)
 366                 {
 367                   /* Failed to load the library.  */
 368                   ni->library->lib_handle = (void *) -1l;
 369                   __set_errno (saved_errno);
 370                 }
 371             }
 372
 373           if (ni->library->lib_handle == (void *) -1l)
 374             /* Library not found => function not found.  */
 375             result = NULL;
 376           else
 377             {
 378               /* Get the desired function.  */
 379               size_t namlen = (5 + strlen (ni->library->name) + 1
 380                                + strlen (fct_name) + 1);
 381               char name[namlen];
 382
 383               /* Construct the function name.  */
 384               __stpcpy (__stpcpy (__stpcpy (__stpcpy (name, "_nss_"),
 385                                             ni->library->name),
 386                                   "_"),
 387                         fct_name);
 388
 389               /* Look up the symbol.  */
 390               result = __libc_dlsym (ni->library->lib_handle, name);
 391             }
 392 #else
 393           /* We can't get function address dynamically in static linking. */
 394           {
 395 # define DEFINE_ENT(h,nm)                                                     \
 396             { #h"_get"#nm"ent_r", _nss_##h##_get##nm##ent_r },                \
 397             { #h"_end"#nm"ent", _nss_##h##_end##nm##ent },                    \
 398             { #h"_set"#nm"ent", _nss_##h##_set##nm##ent },
 399 # define DEFINE_GET(h,nm)                                                     \
 400             { #h"_get"#nm"_r", _nss_##h##_get##nm##_r },
 401 # define DEFINE_GETBY(h,nm,ky)                                                \
 402             { #h"_get"#nm"by"#ky"_r", _nss_##h##_get##nm##by##ky##_r },
 403             static struct fct_tbl { const char *fname; void *fp; } *tp, tbl[] =
 404               {
 405 # include "function.def"
 406                 { NULL, NULL }
 407               };
 408             size_t namlen = (5 + strlen (ni->library->name) + 1
 409                              + strlen (fct_name) + 1);
 410             char name[namlen];
 411
 412             /* Construct the function name.  */
 413             __stpcpy (__stpcpy (__stpcpy (name, ni->library->name),
 414                                 "_"),
 415                       fct_name);
 416
 417             result = NULL;
 418             for (tp = &tbl[0]; tp->fname; tp++)
 419               if (strcmp (tp->fname, name) == 0)
 420                 {
 421                   result = tp->fp;
 422                   break;
 423                 }
 424           }
 425 #endif
 426
 427           /* Remember function pointer for later calls.  Even if null, we
 428              record it so a second try needn't search the library again.  */
 429           known->fct_ptr = result;
 430           PTR_MANGLE (known->fct_ptr);
 431         }
 432     }
 433
 434   /* Remove the lock.  */
 435   __libc_lock_unlock (lock);
 436
 437   return result;
 438 }
 439 libc_hidden_def (__nss_lookup_function)
 440
 441
 442 static name_database *
 443 internal_function
 444 nss_parse_file (const char *fname)
 445 {
 446   FILE *fp;
 447   name_database *result;
 448   name_database_entry *last;
 449   char *line;
 450   size_t len;
 451
 452   /* Open the configuration file.  */
 453   fp = fopen (fname, "rc");
 454   if (fp == NULL)
 455     return NULL;
 456
 457   /* No threads use this stream.  */
 458   __fsetlocking (fp, FSETLOCKING_BYCALLER);
 459
 460   result = (name_database *) malloc (sizeof (name_database));
 461   if (result == NULL)
 462     return NULL;
 463
 464   result->entry = NULL;
 465   result->library = NULL;
 466   last = NULL;
 467   line = NULL;
 468   len = 0;
 469   do
 470     {
 471       name_database_entry *this;
 472       ssize_t n;
 473
 474       n = __getline (&line, &len, fp);
 475       if (n < 0)
 476         break;
 477       if (line[n - 1] == '\n')
 478         line[n - 1] = '\0';
 479
 480       /* Because the file format does not know any form of quoting we
 481          can search forward for the next '#' character and if found
 482          make it terminating the line.  */
 483       *__strchrnul (line, '#') = '\0';
 484
 485       /* If the line is blank it is ignored.  */
 486       if (line[0] == '\0')
 487         continue;
 488
 489       /* Each line completely specifies the actions for a database.  */
 490       this = nss_getline (line);
 491       if (this != NULL)
 492         {
 493           if (last != NULL)
 494             last->next = this;
 495           else
 496             result->entry = this;
 497
 498           last = this;
 499         }
 500     }
 501   while (!feof_unlocked (fp));
 502
 503   /* Free the buffer.  */
 504   free (line);
 505   /* Close configuration file.  */
 506   fclose (fp);
 507
 508   return result;
 509 }
 510
 511
 512 /* Read the source names:
 513         `( <source> ( "[" "!"? (<status> "=" <action> )+ "]" )? )*'
 514    */
 515 static service_user *
 516 internal_function
 517 nss_parse_service_list (const char *line)
 518 {
 519   service_user *result = NULL, **nextp = &result;
 520
 521   while (1)
 522     {
 523       service_user *new_service;
 524       const char *name;
 525
 526       while (isspace (line[0]))
 527         ++line;
 528       if (line[0] == '\0')
 529         /* No source specified.  */
 530         return result;
 531
 532       /* Read <source> identifier.  */
 533       name = line;
 534       while (line[0] != '\0' && !isspace (line[0]) && line[0] != '[')
 535         ++line;
 536       if (name == line)
 537         return result;
 538
 539
 540       new_service = (service_user *) malloc (sizeof (service_user)
 541                                              + (line - name + 1));
 542       if (new_service == NULL)
 543         return result;
 544
 545       *((char *) __mempcpy (new_service->name, name, line - name)) = '\0';
 546
 547       /* Set default actions.  */
 548       new_service->actions[2 + NSS_STATUS_TRYAGAIN] = NSS_ACTION_CONTINUE;
 549       new_service->actions[2 + NSS_STATUS_UNAVAIL] = NSS_ACTION_CONTINUE;
 550       new_service->actions[2 + NSS_STATUS_NOTFOUND] = NSS_ACTION_CONTINUE;
 551       new_service->actions[2 + NSS_STATUS_SUCCESS] = NSS_ACTION_RETURN;
 552       new_service->actions[2 + NSS_STATUS_RETURN] = NSS_ACTION_RETURN;
 553       new_service->library = NULL;
 554       new_service->known = NULL;
 555       new_service->next = NULL;
 556
 557       while (isspace (line[0]))
 558         ++line;
 559
 560       if (line[0] == '[')
 561         {
 562           /* Read criterions.  */
 563           do
 564             ++line;
 565           while (line[0] != '\0' && isspace (line[0]));
 566
 567           do
 568             {
 569               int not;
 570               enum nss_status status;
 571               lookup_actions action;
 572
 573               /* Grok ! before name to mean all statii but that one.  */
 574               not = line[0] == '!';
 575               if (not)
 576                 ++line;
 577
 578               /* Read status name.  */
 579               name = line;
 580               while (line[0] != '\0' && !isspace (line[0]) && line[0] != '='
 581                      && line[0] != ']')
 582                 ++line;
 583
 584               /* Compare with known statii.  */
 585               if (line - name == 7)
 586                 {
 587                   if (__strncasecmp (name, "SUCCESS", 7) == 0)
 588                     status = NSS_STATUS_SUCCESS;
 589                   else if (__strncasecmp (name, "UNAVAIL", 7) == 0)
 590                     status = NSS_STATUS_UNAVAIL;
 591                   else
 592                     return result;
 593                 }
 594               else if (line - name == 8)
 595                 {
 596                   if (__strncasecmp (name, "NOTFOUND", 8) == 0)
 597                     status = NSS_STATUS_NOTFOUND;
 598                   else if (__strncasecmp (name, "TRYAGAIN", 8) == 0)
 599                     status = NSS_STATUS_TRYAGAIN;
 600                   else
 601                     return result;
 602                 }
 603               else
 604                 return result;
 605
 606               while (isspace (line[0]))
 607                 ++line;
 608               if (line[0] != '=')
 609                 return result;
 610               do
 611                 ++line;
 612               while (isspace (line[0]));
 613
 614               name = line;
 615               while (line[0] != '\0' && !isspace (line[0]) && line[0] != '='
 616                      && line[0] != ']')
 617                 ++line;
 618
 619               if (line - name == 6 && __strncasecmp (name, "RETURN", 6) == 0)
 620                 action = NSS_ACTION_RETURN;
 621               else if (line - name == 8
 622                        && __strncasecmp (name, "CONTINUE", 8) == 0)
 623                 action = NSS_ACTION_CONTINUE;
 624               else
 625                 return result;
 626
 627               if (not)
 628                 {
 629                   /* Save the current action setting for this status,
 630                      set them all to the given action, and reset this one.  */
 631                   const lookup_actions save = new_service->actions[2 + status];
 632                   new_service->actions[2 + NSS_STATUS_TRYAGAIN] = action;
 633                   new_service->actions[2 + NSS_STATUS_UNAVAIL] = action;
 634                   new_service->actions[2 + NSS_STATUS_NOTFOUND] = action;
 635                   new_service->actions[2 + NSS_STATUS_SUCCESS] = action;
 636                   new_service->actions[2 + status] = save;
 637                 }
 638               else
 639                 new_service->actions[2 + status] = action;
 640
 641               /* Skip white spaces.  */
 642               while (isspace (line[0]))
 643                 ++line;
 644             }
 645           while (line[0] != ']');
 646
 647           /* Skip the ']'.  */
 648           ++line;
 649         }
 650
 651       *nextp = new_service;
 652       nextp = &new_service->next;
 653     }
 654 }
 655
 656 static name_database_entry *
 657 internal_function
 658 nss_getline (char *line)
 659 {
 660   const char *name;
 661   name_database_entry *result;
 662   size_t len;
 663
 664   /* Ignore leading white spaces.  ATTENTION: this is different from
 665      what is implemented in Solaris.  The Solaris man page says a line
 666      beginning with a white space character is ignored.  We regard
 667      this as just another misfeature in Solaris.  */
 668   while (isspace (line[0]))
 669     ++line;
 670
 671   /* Recognize `<database> ":"'.  */
 672   name = line;
 673   while (line[0] != '\0' && !isspace (line[0]) && line[0] != ':')
 674     ++line;
 675   if (line[0] == '\0' || name == line)
 676     /* Syntax error.  */
 677     return NULL;
 678   *line++ = '\0';
 679
 680   len = strlen (name) + 1;
 681
 682   result = (name_database_entry *) malloc (sizeof (name_database_entry) + len);
 683   if (result == NULL)
 684     return NULL;
 685
 686   /* Save the database name.  */
 687   memcpy (result->name, name, len);
 688
 689   /* Parse the list of services.  */
 690   result->service = nss_parse_service_list (line);
 691
 692   result->next = NULL;
 693   return result;
 694 }
 695
 696
 697 static service_library *
 698 internal_function
 699 nss_new_service (name_database *database, const char *name)
 700 {
 701   service_library **currentp = &database->library;
 702
 703   while (*currentp != NULL)
 704     {
 705       if (strcmp ((*currentp)->name, name) == 0)
 706         return *currentp;
 707       currentp = &(*currentp)->next;
 708     }
 709
 710   /* We have to add the new service.  */
 711   *currentp = (service_library *) malloc (sizeof (service_library));
 712   if (*currentp == NULL)
 713     return NULL;
 714
 715   (*currentp)->name = name;
 716   (*currentp)->lib_handle = NULL;
 717   (*currentp)->next = NULL;
 718
 719   return *currentp;
 720 }
 721
 722
 723 /* Called by nscd and nscd alone.  */
 724 void
 725 __nss_disable_nscd (void)
 726 {
 727   /* Disable all uses of NSCD.  */
 728   __nss_not_use_nscd_passwd = -1;
 729   __nss_not_use_nscd_group = -1;
 730   __nss_not_use_nscd_hosts = -1;
 731   __nss_not_use_nscd_services = -1;
 732 }
 733
 734
 735 /* Free all resources if necessary.  */
 736 libc_freeres_fn (free_mem)
 737 {
 738   name_database *top = service_table;
 739   name_database_entry *entry;
 740   service_library *library;
 741
 742   if (top == NULL)
 743     /* Maybe we have not read the nsswitch.conf file.  */
 744     return;
 745
 746   /* Don't disturb ongoing other threads (if there are any).  */
 747   service_table = NULL;
 748
 749   entry = top->entry;
 750   while (entry != NULL)
 751     {
 752       name_database_entry *olde = entry;
 753       service_user *service = entry->service;
 754
 755       while (service != NULL)
 756         {
 757           service_user *olds = service;
 758
 759           if (service->known != NULL)
 760             __tdestroy (service->known, free);
 761
 762           service = service->next;
 763           free (olds);
 764         }
 765
 766       entry = entry->next;
 767       free (olde);
 768     }
 769
 770   library = top->library;
 771   while (library != NULL)
 772     {
 773       service_library *oldl = library;
 774
 775       if (library->lib_handle && library->lib_handle != (void *) -1l)
 776         __libc_dlclose (library->lib_handle);
 777
 778       library = library->next;
 779       free (oldl);
 780     }
 781
 782   free (top);
 783 }