nis/nss-default.c

   1 /* Copyright (C) 1996, 2001, 2004, 2006 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #include <ctype.h>
  20 #include <stdio.h>
  21 #include <stdio_ext.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <bits/libc-lock.h>
  25
  26 #include <libnsl.h>
  27
  28
  29 /* Path of the file.  */
  30 static const char default_nss[] = "/etc/default/nss";
  31
  32 /* Flags once read from the file.  */
  33 static int default_nss_flags;
  34
  35 /* Code to make sure we call 'init' once.  */
  36 __libc_once_define (static, once);
  37
  38
  39 static void
  40 init (void)
  41 {
  42   FILE *fp = fopen (default_nss, "rc");
  43   if (fp != NULL)
  44     {
  45       char *line = NULL;
  46       size_t linelen = 0;
  47
  48       __fsetlocking (fp, FSETLOCKING_BYCALLER);
  49
  50       while (!feof_unlocked (fp))
  51         {
  52           ssize_t n = getline (&line, &linelen, fp);
  53           if (n <= 0)
  54             break;
  55
  56           /* There currently are only two variables we expect, so
  57              simplify the parsing.  Recognize only
  58
  59                NETID_AUTHORITATIVE = TRUE
  60                SERVICES_AUTHORITATIVE = TRUE
  61
  62              with arbitrary white spaces.  */
  63           char *cp = line;
  64           while (isspace (*cp))
  65             ++cp;
  66
  67           /* Recognize comment lines.  */
  68           if (*cp == '#')
  69             continue;
  70
  71           static const char netid_authoritative[] = "NETID_AUTHORITATIVE";
  72           static const char services_authoritative[]
  73             = "SERVICES_AUTHORITATIVE";
  74           size_t flag_len;
  75           if (strncmp (cp, netid_authoritative,
  76                        flag_len = sizeof (netid_authoritative) - 1) != 0
  77               && strncmp (cp, services_authoritative,
  78                           flag_len = sizeof (services_authoritative) - 1)
  79                  != 0)
  80             continue;
  81
  82           cp += flag_len;
  83           while (isspace (*cp))
  84             ++cp;
  85           if (*cp++ != '=')
  86             continue;
  87           while (isspace (*cp))
  88             ++cp;
  89
  90           if (strncmp (cp, "TRUE", 4) != 0)
  91             continue;
  92           cp += 4;
  93
  94           while (isspace (*cp))
  95             ++cp;
  96
  97           if (*cp == '\0')
  98             default_nss_flags |= (flag_len == sizeof (netid_authoritative) - 1
  99                                   ? NSS_FLAG_NETID_AUTHORITATIVE
 100                                   : NSS_FLAG_SERVICES_AUTHORITATIVE);
 101         }
 102
 103       free (line);
 104
 105       fclose (fp);
 106     }
 107 }
 108
 109
 110 int
 111 _nsl_default_nss (void)
 112 {
 113   /* If we have not yet read the file yet do it now.  */
 114   __libc_once (once, init);
 115
 116   return default_nss_flags;
 117 }