nis/nss-default.c

   1 /* Copyright (C) 1996,2001,2004,2006,2007,2010,2011
   2    Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   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    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <ctype.h>
  20 #include <errno.h>
  21 #include <stdio.h>
  22 #include <stdio_ext.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <bits/libc-lock.h>
  26
  27 #include <libnsl.h>
  28
  29
  30 /* Path of the file.  */
  31 static const char default_nss[] = "/etc/default/nss";
  32
  33 /* Flags once read from the file.  */
  34 static int default_nss_flags;
  35
  36 /* Code to make sure we call 'init' once.  */
  37 __libc_once_define (static, once);
  38
  39 /* Table of the recognized variables.  */
  40 static const struct
  41 {
  42   char name[23];
  43   unsigned int len;
  44   int flag;
  45 } vars[] =
  46   {
  47 #define STRNLEN(s) s, sizeof (s) - 1
  48     { STRNLEN ("NETID_AUTHORITATIVE"), NSS_FLAG_NETID_AUTHORITATIVE },
  49     { STRNLEN ("SERVICES_AUTHORITATIVE"), NSS_FLAG_SERVICES_AUTHORITATIVE },
  50     { STRNLEN ("SETENT_BATCH_READ"), NSS_FLAG_SETENT_BATCH_READ },
  51     { STRNLEN ("ADJUNCT_AS_SHADOW"), NSS_FLAG_ADJUNCT_AS_SHADOW },
  52   };
  53 #define nvars (sizeof (vars) / sizeof (vars[0]))
  54
  55
  56 static void
  57 init (void)
  58 {
  59   int saved_errno = errno;
  60   FILE *fp = fopen (default_nss, "rce");
  61   if (fp != NULL)
  62     {
  63       char *line = NULL;
  64       size_t linelen = 0;
  65
  66       __fsetlocking (fp, FSETLOCKING_BYCALLER);
  67
  68       while (!feof_unlocked (fp))
  69         {
  70           ssize_t n = getline (&line, &linelen, fp);
  71           if (n <= 0)
  72             break;
  73
  74           /* Recognize only
  75
  76                <THE-VARIABLE> = TRUE
  77
  78              with arbitrary white spaces.  */
  79           char *cp = line;
  80           while (isspace (*cp))
  81             ++cp;
  82
  83           /* Recognize comment lines.  */
  84           if (*cp == '#')
  85             continue;
  86
  87           int idx;
  88           for (idx = 0; idx < nvars; ++idx)
  89             if (strncmp (cp, vars[idx].name, vars[idx].len) == 0)
  90               break;
  91           if (idx == nvars)
  92             continue;
  93
  94           cp += vars[idx].len;
  95           while (isspace (*cp))
  96             ++cp;
  97           if (*cp++ != '=')
  98             continue;
  99           while (isspace (*cp))
 100             ++cp;
 101
 102           if (strncmp (cp, "TRUE", 4) != 0)
 103             continue;
 104           cp += 4;
 105
 106           while (isspace (*cp))
 107             ++cp;
 108
 109           if (*cp == '\0')
 110             default_nss_flags |= vars[idx].flag;
 111         }
 112
 113       free (line);
 114
 115       fclose (fp);
 116     }
 117   __set_errno (saved_errno);
 118 }
 119
 120
 121 int
 122 _nsl_default_nss (void)
 123 {
 124   /* If we have not yet read the file yet do it now.  */
 125   __libc_once (once, init);
 126
 127   return default_nss_flags;
 128 }