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 /* Table of the recognized variables.  */
  39 static const struct
  40 {
  41   char name[23];
  42   unsigned int len;
  43   int flag;
  44 } vars[] =
  45   {
  46 #define STRNLEN(s) s, sizeof (s) - 1
  47     { STRNLEN ("NETID_AUTHORITATIVE"), NSS_FLAG_NETID_AUTHORITATIVE },
  48     { STRNLEN ("SERVICES_AUTHORITATIVE"), NSS_FLAG_SERVICES_AUTHORITATIVE },
  49     { STRNLEN ("SETENT_BATCH_READ"), NSS_FLAG_SETENT_BATCH_READ }
  50   };
  51 #define nvars (sizeof (vars) / sizeof (vars[0]))
  52
  53
  54 static void
  55 init (void)
  56 {
  57   FILE *fp = fopen (default_nss, "rc");
  58   if (fp != NULL)
  59     {
  60       char *line = NULL;
  61       size_t linelen = 0;
  62
  63       __fsetlocking (fp, FSETLOCKING_BYCALLER);
  64
  65       while (!feof_unlocked (fp))
  66         {
  67           ssize_t n = getline (&line, &linelen, fp);
  68           if (n <= 0)
  69             break;
  70
  71           /* Recognize only
  72
  73                <THE-VARIABLE> = TRUE
  74
  75              with arbitrary white spaces.  */
  76           char *cp = line;
  77           while (isspace (*cp))
  78             ++cp;
  79
  80           /* Recognize comment lines.  */
  81           if (*cp == '#')
  82             continue;
  83
  84           int idx;
  85           for (idx = 0; idx < nvars; ++idx)
  86             if (strncmp (cp, vars[idx].name, vars[idx].len) == 0)
  87               break;
  88           if (idx == nvars)
  89             continue;
  90
  91           cp += vars[idx].len;
  92           while (isspace (*cp))
  93             ++cp;
  94           if (*cp++ != '=')
  95             continue;
  96           while (isspace (*cp))
  97             ++cp;
  98
  99           if (strncmp (cp, "TRUE", 4) != 0)
 100             continue;
 101           cp += 4;
 102
 103           while (isspace (*cp))
 104             ++cp;
 105
 106           if (*cp == '\0')
 107             default_nss_flags |= vars[idx].flag;
 108         }
 109
 110       free (line);
 111
 112       fclose (fp);
 113     }
 114 }
 115
 116
 117 int
 118 _nsl_default_nss (void)
 119 {
 120   /* If we have not yet read the file yet do it now.  */
 121   __libc_once (once, init);
 122
 123   return default_nss_flags;
 124 }