nss/nsswitch.c

   1 /* Copyright (C) 1996-2020 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, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <ctype.h>
  20 #include <dlfcn.h>
  21 #include <errno.h>
  22 #include <netdb.h>
  23 #include <libc-lock.h>
  24 #include <search.h>
  25 #include <stdio.h>
  26 #include <stdio_ext.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29
  30 #include <aliases.h>
  31 #include <grp.h>
  32 #include <netinet/ether.h>
  33 #include <pwd.h>
  34 #include <shadow.h>
  35 #include <unistd.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 #include <sysdep.h>
  44 #include <config.h>
  45
  46 /* Declare external database variables.  */
  47 #define DEFINE_DATABASE(name)                                                 \
  48   nss_action_list __nss_##name##_database attribute_hidden;                   \
  49   weak_extern (__nss_##name##_database)
  50 #include "databases.def"
  51 #undef DEFINE_DATABASE
  52
  53
  54 #undef DEFINE_DATABASE
  55 #define DEFINE_DATABASE(name)  #name,
  56 static const char * database_names[] = {
  57 #include "databases.def"
  58   NULL
  59 };
  60
  61 #ifdef USE_NSCD
  62 /* Flags whether custom rules for database is set.  */
  63 bool __nss_database_custom[NSS_DBSIDX_max];
  64 #endif
  65
  66
  67 /*__libc_lock_define_initialized (static, lock)*/
  68
  69 /* -1 == database not found
  70     0 == database entry pointer stored */
  71 int
  72 __nss_database_lookup2 (const char *database, const char *alternate_name,
  73                         const char *defconfig, nss_action_list *ni)
  74 {
  75   int database_id;
  76
  77   for (database_id = 0; database_names[database_id]; database_id++)
  78     if (strcmp (database_names[database_id], database) == 0)
  79         break;
  80
  81   if (database_names[database_id] == NULL)
  82     return -1;
  83
  84   /* If *NI is NULL, the database was not mentioned in nsswitch.conf.
  85      If *NI is not NULL, but *NI->module is NULL, the database was in
  86      nsswitch.conf but listed no actions.  We test for the former.  */
  87   if (__nss_database_get (database_id, ni) && *ni != NULL)
  88     {
  89       /* Success.  */
  90       return 0;
  91     }
  92   else
  93     {
  94       /* Failure.  */
  95       return -1;
  96     }
  97 }
  98 libc_hidden_def (__nss_database_lookup2)
  99
 100
 101 /* -1 == not found
 102     0 == function found
 103     1 == finished */
 104 int
 105 __nss_lookup (nss_action_list *ni, const char *fct_name, const char *fct2_name,
 106               void **fctp)
 107 {
 108   *fctp = __nss_lookup_function (*ni, fct_name);
 109   if (*fctp == NULL && fct2_name != NULL)
 110     *fctp = __nss_lookup_function (*ni, fct2_name);
 111
 112   while (*fctp == NULL
 113          && nss_next_action (*ni, NSS_STATUS_UNAVAIL) == NSS_ACTION_CONTINUE
 114          && (*ni)[1].module != NULL)
 115     {
 116       ++(*ni);
 117
 118       *fctp = __nss_lookup_function (*ni, fct_name);
 119       if (*fctp == NULL && fct2_name != NULL)
 120         *fctp = __nss_lookup_function (*ni, fct2_name);
 121     }
 122
 123   return *fctp != NULL ? 0 : (*ni)[1].module == NULL ? 1 : -1;
 124 }
 125 libc_hidden_def (__nss_lookup)
 126
 127
 128 /* -1 == not found
 129     0 == adjusted for next function
 130     1 == finished */
 131 int
 132 __nss_next2 (nss_action_list *ni, const char *fct_name, const char *fct2_name,
 133              void **fctp, int status, int all_values)
 134 {
 135   if (all_values)
 136     {
 137       if (nss_next_action (*ni, NSS_STATUS_TRYAGAIN) == NSS_ACTION_RETURN
 138           && nss_next_action (*ni, NSS_STATUS_UNAVAIL) == NSS_ACTION_RETURN
 139           && nss_next_action (*ni, NSS_STATUS_NOTFOUND) == NSS_ACTION_RETURN
 140           && nss_next_action (*ni, NSS_STATUS_SUCCESS) == NSS_ACTION_RETURN)
 141         return 1;
 142     }
 143   else
 144     {
 145       /* This is really only for debugging.  */
 146       if (__builtin_expect (NSS_STATUS_TRYAGAIN > status
 147                             || status > NSS_STATUS_RETURN, 0))
 148          __libc_fatal ("Illegal status in __nss_next.\n");
 149
 150        if (nss_next_action (*ni, status) == NSS_ACTION_RETURN)
 151          return 1;
 152     }
 153
 154   if ((*ni)[1].module == NULL)
 155     return -1;
 156
 157   do
 158     {
 159       ++(*ni);
 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   while (*fctp == NULL
 166          && nss_next_action (*ni, NSS_STATUS_UNAVAIL) == NSS_ACTION_CONTINUE
 167          && (*ni)[1].module != NULL);
 168
 169   return *fctp != NULL ? 0 : -1;
 170 }
 171 libc_hidden_def (__nss_next2)
 172
 173 void *
 174 __nss_lookup_function (nss_action_list ni, const char *fct_name)
 175 {
 176   if (ni->module == NULL)
 177     return NULL;
 178   return __nss_module_get_function (ni->module, fct_name);
 179 }
 180 libc_hidden_def (__nss_lookup_function)