nss/nsswitch.c

   1 /* Copyright (C) 1996-1999,2001-2007,2009,2010 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 /* Flags whether custom rules for database is set.  */
  75 bool __nss_database_custom[NSS_DBSIDX_max];
  76
  77
  78 __libc_lock_define_initialized (static, lock)
  79
  80 #if !defined DO_STATIC_NSS || defined SHARED
  81 /* String with revision number of the shared object files.  */
  82 static const char *const __nss_shlib_revision = LIBNSS_FILES_SO + 15;
  83 #endif
  84
  85 /* The root of the whole data base.  */
  86 static name_database *service_table;
  87
  88
  89 /* -1 == database not found
  90     0 == database entry pointer stored */
  91 int
  92 __nss_database_lookup (const char *database, const char *alternate_name,
  93                        const char *defconfig, service_user **ni)
  94 {
  95   /* Prevent multiple threads to change the service table.  */
  96   __libc_lock_lock (lock);
  97
  98   /* Reconsider database variable in case some other thread called
  99      `__nss_configure_lookup' while we waited for the lock.  */
 100   if (*ni != NULL)
 101     {
 102       __libc_lock_unlock (lock);
 103       return 0;
 104     }
 105
 106   /* Are we initialized yet?  */
 107   if (service_table == NULL)
 108     /* Read config file.  */
 109     service_table = nss_parse_file (_PATH_NSSWITCH_CONF);
 110
 111   /* Test whether configuration data is available.  */
 112   if (service_table != NULL)
 113     {
 114       /* Return first `service_user' entry for DATABASE.  */
 115       name_database_entry *entry;
 116
 117       /* XXX Could use some faster mechanism here.  But each database is
 118          only requested once and so this might not be critical.  */
 119       for (entry = service_table->entry; entry != NULL; entry = entry->next)
 120         if (strcmp (database, entry->name) == 0)
 121           *ni = entry->service;
 122
 123       if (*ni == NULL && alternate_name != NULL)
 124         /* We haven't found an entry so far.  Try to find it with the
 125            alternative name.  */
 126         for (entry = service_table->entry; entry != NULL; entry = entry->next)
 127           if (strcmp (alternate_name, entry->name) == 0)
 128             *ni = entry->service;
 129     }
 130
 131   /* No configuration data is available, either because nsswitch.conf
 132      doesn't exist or because it doesn't has a line for this database.
 133
 134      DEFCONFIG specifies the default service list for this database,
 135      or null to use the most common default.  */
 136   if (*ni == NULL)
 137     *ni = nss_parse_service_list (defconfig
 138                                   ?: "nis [NOTFOUND=return] files");
 139
 140   __libc_lock_unlock (lock);
 141
 142   return 0;
 143 }
 144 libc_hidden_def (__nss_database_lookup)
 145
 146
 147 /* -1 == not found
 148     0 == function found
 149     1 == finished */
 150 int
 151 __nss_lookup (service_user **ni, const char *fct_name, const char *fct2_name,
 152               void **fctp)
 153 {
 154   *fctp = __nss_lookup_function (*ni, fct_name);
 155   if (*fctp == NULL && fct2_name != NULL)
 156     *fctp = __nss_lookup_function (*ni, fct2_name);
 157
 158   while (*fctp == NULL
 159          && nss_next_action (*ni, NSS_STATUS_UNAVAIL) == NSS_ACTION_CONTINUE
 160          && (*ni)->next != NULL)
 161     {
 162       *ni = (*ni)->next;
 163
 164       *fctp = __nss_lookup_function (*ni, fct_name);
 165       if (*fctp == NULL && fct2_name != NULL)
 166         *fctp = __nss_lookup_function (*ni, fct2_name);
 167     }
 168
 169   return *fctp != NULL ? 0 : (*ni)->next == NULL ? 1 : -1;
 170 }
 171
 172
 173 /* -1 == not found
 174     0 == adjusted for next function
 175     1 == finished */
 176 int
 177 __nss_next2 (service_user **ni, const char *fct_name, const char *fct2_name,
 178              void **fctp, int status, int all_values)
 179 {
 180   if (all_values)
 181     {
 182       if (nss_next_action (*ni, NSS_STATUS_TRYAGAIN) == NSS_ACTION_RETURN
 183           && nss_next_action (*ni, NSS_STATUS_UNAVAIL) == NSS_ACTION_RETURN
 184           && nss_next_action (*ni, NSS_STATUS_NOTFOUND) == NSS_ACTION_RETURN
 185           && nss_next_action (*ni, NSS_STATUS_SUCCESS) == NSS_ACTION_RETURN)
 186         return 1;
 187     }
 188   else
 189     {
 190       /* This is really only for debugging.  */
 191       if (__builtin_expect (NSS_STATUS_TRYAGAIN > status
 192                             || status > NSS_STATUS_RETURN, 0))
 193          __libc_fatal ("illegal status in __nss_next");
 194
 195        if (nss_next_action (*ni, status) == NSS_ACTION_RETURN)
 196          return 1;
 197     }
 198
 199   if ((*ni)->next == NULL)
 200     return -1;
 201
 202   do
 203     {
 204       *ni = (*ni)->next;
 205
 206       *fctp = __nss_lookup_function (*ni, fct_name);
 207       if (*fctp == NULL && fct2_name != NULL)
 208         *fctp = __nss_lookup_function (*ni, fct2_name);
 209     }
 210   while (*fctp == NULL
 211          && nss_next_action (*ni, NSS_STATUS_UNAVAIL) == NSS_ACTION_CONTINUE
 212          && (*ni)->next != NULL);
 213
 214   return *fctp != NULL ? 0 : -1;
 215 }
 216 libc_hidden_def (__nss_next2)
 217
 218
 219 int
 220 attribute_compat_text_section
 221 __nss_next (service_user **ni, const char *fct_name, void **fctp, int status,
 222             int all_values)
 223 {
 224   return __nss_next2 (ni, fct_name, NULL, fctp, status, all_values);
 225 }
 226
 227
 228 int
 229 __nss_configure_lookup (const char *dbname, const char *service_line)
 230 {
 231   service_user *new_db;
 232   size_t cnt;
 233
 234   for (cnt = 0; cnt < ndatabases; ++cnt)
 235     {
 236       int cmp = strcmp (dbname, databases[cnt].name);
 237       if (cmp == 0)
 238         break;
 239       if (cmp < 0)
 240         {
 241           __set_errno (EINVAL);
 242           return -1;
 243         }
 244     }
 245
 246   if (cnt == ndatabases)
 247     {
 248       __set_errno (EINVAL);
 249       return -1;
 250     }
 251
 252   /* Test whether it is really used.  */
 253   if (databases[cnt].dbp == NULL)
 254     /* Nothing to do, but we could do.  */
 255     return 0;
 256
 257   /* Try to generate new data.  */
 258   new_db = nss_parse_service_list (service_line);
 259   if (new_db == NULL)
 260     {
 261       /* Illegal service specification.  */
 262       __set_errno (EINVAL);
 263       return -1;
 264     }
 265
 266   /* Prevent multiple threads to change the service table.  */
 267   __libc_lock_lock (lock);
 268
 269   /* Install new rules.  */
 270   *databases[cnt].dbp = new_db;
 271   __nss_database_custom[cnt] = true;
 272
 273   __libc_lock_unlock (lock);
 274
 275   return 0;
 276 }
 277
 278
 279 /* Comparison function for searching NI->known tree.  */
 280 static int
 281 known_compare (const void *p1, const void *p2)
 282 {
 283   return p1 == p2 ? 0 : strcmp (*(const char *const *) p1,
 284                                 *(const char *const *) p2);
 285 }
 286
 287
 288 void *
 289 __nss_lookup_function (service_user *ni, const char *fct_name)
 290 {
 291   void **found, *result;
 292
 293   /* We now modify global data.  Protect it.  */
 294   __libc_lock_lock (lock);
 295
 296   /* Search the tree of functions previously requested.  Data in the
 297      tree are `known_function' structures, whose first member is a
 298      `const char *', the lookup key.  The search returns a pointer to
 299      the tree node structure; the first member of the is a pointer to
 300      our structure (i.e. what will be a `known_function'); since the
 301      first member of that is the lookup key string, &FCT_NAME is close
 302      enough to a pointer to our structure to use as a lookup key that
 303      will be passed to `known_compare' (above).  */
 304
 305   found = __tsearch (&fct_name, &ni->known, &known_compare);
 306   if (*found != &fct_name)
 307     {
 308       /* The search found an existing structure in the tree.  */
 309       result = ((known_function *) *found)->fct_ptr;
 310       PTR_DEMANGLE (result);
 311     }
 312   else
 313     {
 314       /* This name was not known before.  Now we have a node in the tree
 315          (in the proper sorted position for FCT_NAME) that points to
 316          &FCT_NAME instead of any real `known_function' structure.
 317          Allocate a new structure and fill it in.  */
 318
 319       known_function *known = malloc (sizeof *known);
 320       if (! known)
 321         {
 322         remove_from_tree:
 323           /* Oops.  We can't instantiate this node properly.
 324              Remove it from the tree.  */
 325           __tdelete (&fct_name, &ni->known, &known_compare);
 326           result = NULL;
 327         }
 328       else
 329         {
 330           /* Point the tree node at this new structure.  */
 331           *found = known;
 332           known->fct_name = fct_name;
 333
 334           if (ni->library == NULL)
 335             {
 336               /* This service has not yet been used.  Fetch the service
 337                  library for it, creating a new one if need be.  If there
 338                  is no service table from the file, this static variable
 339                  holds the head of the service_library list made from the
 340                  default configuration.  */
 341               static name_database default_table;
 342               ni->library = nss_new_service (service_table ?: &default_table,
 343                                              ni->name);
 344               if (ni->library == NULL)
 345                 {
 346                   /* This only happens when out of memory.  */
 347                   free (known);
 348                   goto remove_from_tree;
 349                 }
 350             }
 351
 352 #if !defined DO_STATIC_NSS || defined SHARED
 353           if (ni->library->lib_handle == NULL)
 354             {
 355               /* Load the shared library.  */
 356               size_t shlen = (7 + strlen (ni->library->name) + 3
 357                               + strlen (__nss_shlib_revision) + 1);
 358               int saved_errno = errno;
 359               char shlib_name[shlen];
 360
 361               /* Construct shared object name.  */
 362               __stpcpy (__stpcpy (__stpcpy (__stpcpy (shlib_name,
 363                                                       "libnss_"),
 364                                             ni->library->name),
 365                                   ".so"),
 366                         __nss_shlib_revision);
 367
 368               ni->library->lib_handle = __libc_dlopen (shlib_name);
 369               if (ni->library->lib_handle == NULL)
 370                 {
 371                   /* Failed to load the library.  */
 372                   ni->library->lib_handle = (void *) -1l;
 373                   __set_errno (saved_errno);
 374                 }
 375             }
 376
 377           if (ni->library->lib_handle == (void *) -1l)
 378             /* Library not found => function not found.  */
 379             result = NULL;
 380           else
 381             {
 382               /* Get the desired function.  */
 383               size_t namlen = (5 + strlen (ni->library->name) + 1
 384                                + strlen (fct_name) + 1);
 385               char name[namlen];
 386
 387               /* Construct the function name.  */
 388               __stpcpy (__stpcpy (__stpcpy (__stpcpy (name, "_nss_"),
 389                                             ni->library->name),
 390                                   "_"),
 391                         fct_name);
 392
 393               /* Look up the symbol.  */
 394               result = __libc_dlsym (ni->library->lib_handle, name);
 395             }
 396 #else
 397           /* We can't get function address dynamically in static linking. */
 398           {
 399 # define DEFINE_ENT(h,nm)                                                     \
 400             { #h"_get"#nm"ent_r", _nss_##h##_get##nm##ent_r },                \
 401             { #h"_end"#nm"ent", _nss_##h##_end##nm##ent },                    \
 402             { #h"_set"#nm"ent", _nss_##h##_set##nm##ent },
 403 # define DEFINE_GET(h,nm)                                                     \
 404             { #h"_get"#nm"_r", _nss_##h##_get##nm##_r },
 405 # define DEFINE_GETBY(h,nm,ky)                                                \
 406             { #h"_get"#nm"by"#ky"_r", _nss_##h##_get##nm##by##ky##_r },
 407             static struct fct_tbl { const char *fname; void *fp; } *tp, tbl[] =
 408               {
 409 # include "function.def"
 410                 { NULL, NULL }
 411               };
 412             size_t namlen = (5 + strlen (ni->library->name) + 1
 413                              + strlen (fct_name) + 1);
 414             char name[namlen];
 415
 416             /* Construct the function name.  */
 417             __stpcpy (__stpcpy (__stpcpy (name, ni->library->name),
 418                                 "_"),
 419                       fct_name);
 420
 421             result = NULL;
 422             for (tp = &tbl[0]; tp->fname; tp++)
 423               if (strcmp (tp->fname, name) == 0)
 424                 {
 425                   result = tp->fp;
 426                   break;
 427                 }
 428           }
 429 #endif
 430
 431           /* Remember function pointer for later calls.  Even if null, we
 432              record it so a second try needn't search the library again.  */
 433           known->fct_ptr = result;
 434           PTR_MANGLE (known->fct_ptr);
 435         }
 436     }
 437
 438   /* Remove the lock.  */
 439   __libc_lock_unlock (lock);
 440
 441   return result;
 442 }
 443 libc_hidden_def (__nss_lookup_function)
 444
 445
 446 static name_database *
 447 internal_function
 448 nss_parse_file (const char *fname)
 449 {
 450   FILE *fp;
 451   name_database *result;
 452   name_database_entry *last;
 453   char *line;
 454   size_t len;
 455
 456   /* Open the configuration file.  */
 457   fp = fopen (fname, "rc");
 458   if (fp == NULL)
 459     return NULL;
 460
 461   /* No threads use this stream.  */
 462   __fsetlocking (fp, FSETLOCKING_BYCALLER);
 463
 464   result = (name_database *) malloc (sizeof (name_database));
 465   if (result == NULL)
 466     return NULL;
 467
 468   result->entry = NULL;
 469   result->library = NULL;
 470   last = NULL;
 471   line = NULL;
 472   len = 0;
 473   do
 474     {
 475       name_database_entry *this;
 476       ssize_t n;
 477
 478       n = __getline (&line, &len, fp);
 479       if (n < 0)
 480         break;
 481       if (line[n - 1] == '\n')
 482         line[n - 1] = '\0';
 483
 484       /* Because the file format does not know any form of quoting we
 485          can search forward for the next '#' character and if found
 486          make it terminating the line.  */
 487       *__strchrnul (line, '#') = '\0';
 488
 489       /* If the line is blank it is ignored.  */
 490       if (line[0] == '\0')
 491         continue;
 492
 493       /* Each line completely specifies the actions for a database.  */
 494       this = nss_getline (line);
 495       if (this != NULL)
 496         {
 497           if (last != NULL)
 498             last->next = this;
 499           else
 500             result->entry = this;
 501
 502           last = this;
 503         }
 504     }
 505   while (!feof_unlocked (fp));
 506
 507   /* Free the buffer.  */
 508   free (line);
 509   /* Close configuration file.  */
 510   fclose (fp);
 511
 512   return result;
 513 }
 514
 515
 516 /* Read the source names:
 517         `( <source> ( "[" "!"? (<status> "=" <action> )+ "]" )? )*'
 518    */
 519 static service_user *
 520 internal_function
 521 nss_parse_service_list (const char *line)
 522 {
 523   service_user *result = NULL, **nextp = &result;
 524
 525   while (1)
 526     {
 527       service_user *new_service;
 528       const char *name;
 529
 530       while (isspace (line[0]))
 531         ++line;
 532       if (line[0] == '\0')
 533         /* No source specified.  */
 534         return result;
 535
 536       /* Read <source> identifier.  */
 537       name = line;
 538       while (line[0] != '\0' && !isspace (line[0]) && line[0] != '[')
 539         ++line;
 540       if (name == line)
 541         return result;
 542
 543
 544       new_service = (service_user *) malloc (sizeof (service_user)
 545                                              + (line - name + 1));
 546       if (new_service == NULL)
 547         return result;
 548
 549       *((char *) __mempcpy (new_service->name, name, line - name)) = '\0';
 550
 551       /* Set default actions.  */
 552       new_service->actions[2 + NSS_STATUS_TRYAGAIN] = NSS_ACTION_CONTINUE;
 553       new_service->actions[2 + NSS_STATUS_UNAVAIL] = NSS_ACTION_CONTINUE;
 554       new_service->actions[2 + NSS_STATUS_NOTFOUND] = NSS_ACTION_CONTINUE;
 555       new_service->actions[2 + NSS_STATUS_SUCCESS] = NSS_ACTION_RETURN;
 556       new_service->actions[2 + NSS_STATUS_RETURN] = NSS_ACTION_RETURN;
 557       new_service->library = NULL;
 558       new_service->known = NULL;
 559       new_service->next = NULL;
 560
 561       while (isspace (line[0]))
 562         ++line;
 563
 564       if (line[0] == '[')
 565         {
 566           /* Read criterions.  */
 567           do
 568             ++line;
 569           while (line[0] != '\0' && isspace (line[0]));
 570
 571           do
 572             {
 573               int not;
 574               enum nss_status status;
 575               lookup_actions action;
 576
 577               /* Grok ! before name to mean all statii but that one.  */
 578               not = line[0] == '!';
 579               if (not)
 580                 ++line;
 581
 582               /* Read status name.  */
 583               name = line;
 584               while (line[0] != '\0' && !isspace (line[0]) && line[0] != '='
 585                      && line[0] != ']')
 586                 ++line;
 587
 588               /* Compare with known statii.  */
 589               if (line - name == 7)
 590                 {
 591                   if (__strncasecmp (name, "SUCCESS", 7) == 0)
 592                     status = NSS_STATUS_SUCCESS;
 593                   else if (__strncasecmp (name, "UNAVAIL", 7) == 0)
 594                     status = NSS_STATUS_UNAVAIL;
 595                   else
 596                     return result;
 597                 }
 598               else if (line - name == 8)
 599                 {
 600                   if (__strncasecmp (name, "NOTFOUND", 8) == 0)
 601                     status = NSS_STATUS_NOTFOUND;
 602                   else if (__strncasecmp (name, "TRYAGAIN", 8) == 0)
 603                     status = NSS_STATUS_TRYAGAIN;
 604                   else
 605                     return result;
 606                 }
 607               else
 608                 return result;
 609
 610               while (isspace (line[0]))
 611                 ++line;
 612               if (line[0] != '=')
 613                 return result;
 614               do
 615                 ++line;
 616               while (isspace (line[0]));
 617
 618               name = line;
 619               while (line[0] != '\0' && !isspace (line[0]) && line[0] != '='
 620                      && line[0] != ']')
 621                 ++line;
 622
 623               if (line - name == 6 && __strncasecmp (name, "RETURN", 6) == 0)
 624                 action = NSS_ACTION_RETURN;
 625               else if (line - name == 8
 626                        && __strncasecmp (name, "CONTINUE", 8) == 0)
 627                 action = NSS_ACTION_CONTINUE;
 628               else
 629                 return result;
 630
 631               if (not)
 632                 {
 633                   /* Save the current action setting for this status,
 634                      set them all to the given action, and reset this one.  */
 635                   const lookup_actions save = new_service->actions[2 + status];
 636                   new_service->actions[2 + NSS_STATUS_TRYAGAIN] = action;
 637                   new_service->actions[2 + NSS_STATUS_UNAVAIL] = action;
 638                   new_service->actions[2 + NSS_STATUS_NOTFOUND] = action;
 639                   new_service->actions[2 + NSS_STATUS_SUCCESS] = action;
 640                   new_service->actions[2 + status] = save;
 641                 }
 642               else
 643                 new_service->actions[2 + status] = action;
 644
 645               /* Skip white spaces.  */
 646               while (isspace (line[0]))
 647                 ++line;
 648             }
 649           while (line[0] != ']');
 650
 651           /* Skip the ']'.  */
 652           ++line;
 653         }
 654
 655       *nextp = new_service;
 656       nextp = &new_service->next;
 657     }
 658 }
 659
 660 static name_database_entry *
 661 internal_function
 662 nss_getline (char *line)
 663 {
 664   const char *name;
 665   name_database_entry *result;
 666   size_t len;
 667
 668   /* Ignore leading white spaces.  ATTENTION: this is different from
 669      what is implemented in Solaris.  The Solaris man page says a line
 670      beginning with a white space character is ignored.  We regard
 671      this as just another misfeature in Solaris.  */
 672   while (isspace (line[0]))
 673     ++line;
 674
 675   /* Recognize `<database> ":"'.  */
 676   name = line;
 677   while (line[0] != '\0' && !isspace (line[0]) && line[0] != ':')
 678     ++line;
 679   if (line[0] == '\0' || name == line)
 680     /* Syntax error.  */
 681     return NULL;
 682   *line++ = '\0';
 683
 684   len = strlen (name) + 1;
 685
 686   result = (name_database_entry *) malloc (sizeof (name_database_entry) + len);
 687   if (result == NULL)
 688     return NULL;
 689
 690   /* Save the database name.  */
 691   memcpy (result->name, name, len);
 692
 693   /* Parse the list of services.  */
 694   result->service = nss_parse_service_list (line);
 695
 696   result->next = NULL;
 697   return result;
 698 }
 699
 700
 701 static service_library *
 702 internal_function
 703 nss_new_service (name_database *database, const char *name)
 704 {
 705   service_library **currentp = &database->library;
 706
 707   while (*currentp != NULL)
 708     {
 709       if (strcmp ((*currentp)->name, name) == 0)
 710         return *currentp;
 711       currentp = &(*currentp)->next;
 712     }
 713
 714   /* We have to add the new service.  */
 715   *currentp = (service_library *) malloc (sizeof (service_library));
 716   if (*currentp == NULL)
 717     return NULL;
 718
 719   (*currentp)->name = name;
 720   (*currentp)->lib_handle = NULL;
 721   (*currentp)->next = NULL;
 722
 723   return *currentp;
 724 }
 725
 726
 727 /* Called by nscd and nscd alone.  */
 728 void
 729 __nss_disable_nscd (void)
 730 {
 731   /* Disable all uses of NSCD.  */
 732   __nss_not_use_nscd_passwd = -1;
 733   __nss_not_use_nscd_group = -1;
 734   __nss_not_use_nscd_hosts = -1;
 735   __nss_not_use_nscd_services = -1;
 736 }
 737
 738
 739 /* Free all resources if necessary.  */
 740 libc_freeres_fn (free_mem)
 741 {
 742   name_database *top = service_table;
 743   name_database_entry *entry;
 744   service_library *library;
 745
 746   if (top == NULL)
 747     /* Maybe we have not read the nsswitch.conf file.  */
 748     return;
 749
 750   /* Don't disturb ongoing other threads (if there are any).  */
 751   service_table = NULL;
 752
 753   entry = top->entry;
 754   while (entry != NULL)
 755     {
 756       name_database_entry *olde = entry;
 757       service_user *service = entry->service;
 758
 759       while (service != NULL)
 760         {
 761           service_user *olds = service;
 762
 763           if (service->known != NULL)
 764             __tdestroy (service->known, free);
 765
 766           service = service->next;
 767           free (olds);
 768         }
 769
 770       entry = entry->next;
 771       free (olde);
 772     }
 773
 774   library = top->library;
 775   while (library != NULL)
 776     {
 777       service_library *oldl = library;
 778
 779       if (library->lib_handle && library->lib_handle != (void *) -1l)
 780         __libc_dlclose (library->lib_handle);
 781
 782       library = library->next;
 783       free (oldl);
 784     }
 785
 786   free (top);
 787 }