nss/nss_files/files-netgrp.c

   1 /* Netgroup file parser in nss_files modules.
   2 Copyright (C) 1996 Free Software Foundation, Inc.
   3 This file is part of the GNU C Library.
   4 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
   5
   6 The GNU C Library is free software; you can redistribute it and/or
   7 modify it under the terms of the GNU Library General Public License as
   8 published by the Free Software Foundation; either version 2 of the
   9 License, or (at your option) any later version.
  10
  11 The GNU C Library is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 Library General Public License for more details.
  15
  16 You should have received a copy of the GNU Library General Public
  17 License along with the GNU C Library; see the file COPYING.LIB.  If
  18 not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19 Boston, MA 02111-1307, USA.  */
  20
  21 #include <ctype.h>
  22 #include <errno.h>
  23 #include <libc-lock.h>
  24 #include <netdb.h>
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include "nsswitch.h"
  29 #include "netgroup.h"
  30
  31 #define DATAFILE        "/etc/netgroup"
  32
  33
  34 /* Locks the static variables in this file.  */
  35 __libc_lock_define_initialized (static, lock)
  36 \f
  37 /* We share a single place where we store the data for the current
  38    netgroup.  This buffer is allocated by `setnetgrent' and freed on
  39    the next call of this function or when calling `endnetgrent'.  */
  40 static char *data;
  41 static size_t data_size;
  42 static char *cursor;
  43 static int first;
  44
  45
  46 #define EXPAND(needed)                                                        \
  47   do                                                                          \
  48     {                                                                         \
  49       size_t old_cursor = cursor - data;                                      \
  50                                                                               \
  51       data_size += 512 > 2 * needed ? 512 : 2 * needed;                       \
  52       data = realloc (data, data_size);                                       \
  53                                                                               \
  54       if (data == NULL)                                                       \
  55         {                                                                     \
  56           status = NSS_STATUS_UNAVAIL;                                        \
  57           goto the_end;                                                       \
  58         }                                                                     \
  59                                                                               \
  60       cursor = data + old_cursor;                                             \
  61     }                                                                         \
  62   while (0)
  63
  64
  65 enum nss_status
  66 _nss_files_setnetgrent (const char *group)
  67 {
  68   FILE *fp;
  69   enum nss_status status;
  70
  71   if (group[0] == '\0')
  72     return NSS_STATUS_UNAVAIL;
  73
  74   __libc_lock_lock (lock);
  75
  76   /* Find the netgroups file and open it.  */
  77   fp = fopen (DATAFILE, "r");
  78   if (fp == NULL)
  79     status = errno == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
  80   else
  81     {
  82       /* Read the file line by line and try to find the description
  83          GROUP.  We must take care for long lines.  */
  84       char *line = NULL;
  85       size_t line_len = 0;
  86       const ssize_t group_len = strlen (group);
  87
  88       status = NSS_STATUS_NOTFOUND;
  89       cursor = data;
  90
  91       while (!feof (fp))
  92         {
  93           ssize_t curlen = getline (&line, &line_len, fp);
  94           int found;
  95
  96           if (curlen < 0)
  97             {
  98               status = NSS_STATUS_NOTFOUND;
  99               break;
 100             }
 101
 102           found = (curlen > group_len && strncmp (line, group, group_len) == 0
 103                    && isspace (line[group_len]));
 104
 105           /* Read the whole line (including continuation) and store it
 106              if FOUND in nonzero.  Otherwise we don't need it.  */
 107           if (found)
 108             {
 109               /* Store the data from the first line.  */
 110               EXPAND (curlen - group_len);
 111               memcpy (cursor, &line[group_len + 1], curlen - group_len);
 112               cursor += (curlen - group_len) - 1;
 113             }
 114
 115           while (line[curlen - 1] == '\n' && line[curlen - 2] == '\\')
 116             {
 117               /* Yes, we have a continuation line.  */
 118               if (found)
 119                 /* Remove these characters from the stored line.  */
 120                 cursor -= 2;
 121
 122               /* Get netxt line.  */
 123               curlen = getline (&line, &line_len, fp);
 124               if (curlen <= 0)
 125                 break;
 126
 127               if (found)
 128                 {
 129                   /* Make sure we have enough room.  */
 130                   EXPAND (1 + curlen + 1);
 131
 132                   /* Add separator in case next line starts immediately.  */
 133                   *cursor++ = ' ';
 134
 135                   /* Copy new line.  */
 136                   memcpy (cursor, line, curlen + 1);
 137                   cursor += curlen;
 138                 }
 139             }
 140
 141           if (found)
 142             {
 143               /* Now we have read the line.  */
 144               status = NSS_STATUS_SUCCESS;
 145               cursor = data;
 146               first = 1;
 147               break;
 148             }
 149         }
 150
 151     the_end:
 152       /* We don't need the file and the line buffer anymore.  */
 153       free (line);
 154       fclose (fp);
 155     }
 156
 157   __libc_lock_unlock (lock);
 158
 159   return status;
 160 }
 161
 162
 163 int
 164 _nss_files_endnetgrent (void)
 165 {
 166   __libc_lock_lock (lock);
 167
 168   /* Free allocated memory for data if some is present.  */
 169   if (data != NULL)
 170     {
 171       free (data);
 172       data = NULL;
 173       data_size = 0;
 174       cursor = NULL;
 175     }
 176
 177   __libc_lock_unlock (lock);
 178
 179   return NSS_STATUS_SUCCESS;
 180 }
 181
 182
 183 enum nss_status
 184 _nss_netgroup_parseline (char **cursor, struct __netgrent *result,
 185                          char *buffer, int buflen)
 186 {
 187   enum nss_status status;
 188   const char *host, *user, *domain;
 189   char *cp = *cursor;
 190
 191   /* First skip leading spaces.  */
 192   while (isspace (*cp))
 193     ++cp;
 194
 195   if (*cp != '(')
 196     return first ? NSS_STATUS_NOTFOUND : NSS_STATUS_RETURN;
 197
 198   /* Match host name.  */
 199   host = ++cp;
 200   while (*cp != ',')
 201     if (*cp++ == '\0')
 202       return first ? NSS_STATUS_NOTFOUND : NSS_STATUS_RETURN;
 203
 204   /* Match user name.  */
 205   user = ++cp;
 206   while (*cp != ',')
 207     if (*cp++ == '\0')
 208       return first ? NSS_STATUS_NOTFOUND : NSS_STATUS_RETURN;
 209
 210   /* Match domain name.  */
 211   domain = ++cp;
 212   while (*cp != ')')
 213     if (*cp++ == '\0')
 214       return first ? NSS_STATUS_NOTFOUND : NSS_STATUS_RETURN;
 215   ++cp;
 216
 217
 218   /* When we got here we have found an entry.  Before we can copy it
 219      to the private buffer we have to make sure it is big enough.  */
 220   if (cp - host > buflen)
 221     {
 222       __set_errno (ERANGE);
 223       status = NSS_STATUS_UNAVAIL;
 224     }
 225   else
 226     {
 227       memcpy (buffer, host, cp - host);
 228
 229       buffer[(user - host) - 1] = '\0';
 230       result->host = *host == ',' ? NULL : buffer;
 231
 232       buffer[(domain - host) - 1] = '\0';
 233       result->user = *user == ',' ? NULL : buffer + (user - host);
 234
 235       buffer[(cp - host) - 1] = '\0';
 236       result->domain = *domain == ')' ? NULL : buffer + (domain - host);
 237
 238       status = NSS_STATUS_SUCCESS;
 239
 240       /* Rememember where we stopped reading.  */
 241       *cursor = cp;
 242
 243       first = 0;
 244     }
 245
 246   return status;
 247 }
 248
 249
 250 enum nss_status
 251 _nss_files_getnetgrent_r (struct __netgrent *result, char *buffer, int buflen)
 252 {
 253   enum nss_status status;
 254
 255   __libc_lock_lock (lock);
 256
 257   status = _nss_netgroup_parseline (&cursor, result, buffer, buflen);
 258
 259   __libc_lock_unlock (lock);
 260
 261   return status;
 262 }