nss/nss_files/files-netgrp.c

   1 /* Netgroup file parser in nss_files modules.
   2    Copyright (C) 1996-2014 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 Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the 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    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <ctype.h>
  21 #include <errno.h>
  22 #include <netdb.h>
  23 #include <stdio.h>
  24 #include <stdio_ext.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include "nsswitch.h"
  28 #include "netgroup.h"
  29
  30 #define DATAFILE        "/etc/netgroup"
  31
  32 libnss_files_hidden_proto (_nss_files_endnetgrent)
  33
  34 #define EXPAND(needed)                                                        \
  35   do                                                                          \
  36     {                                                                         \
  37       size_t old_cursor = result->cursor - result->data;                      \
  38       void *old_data = result->data;                                          \
  39                                                                               \
  40       result->data_size += 512 > 2 * needed ? 512 : 2 * needed;               \
  41       result->data = realloc (result->data, result->data_size);               \
  42                                                                               \
  43       if (result->data == NULL)                                               \
  44         {                                                                     \
  45           free (old_data);                                                    \
  46           status = NSS_STATUS_UNAVAIL;                                        \
  47           goto the_end;                                                       \
  48         }                                                                     \
  49                                                                               \
  50       result->cursor = result->data + old_cursor;                             \
  51     }                                                                         \
  52   while (0)
  53
  54
  55 enum nss_status
  56 _nss_files_setnetgrent (const char *group, struct __netgrent *result)
  57 {
  58   FILE *fp;
  59   enum nss_status status;
  60
  61   if (group[0] == '\0')
  62     return NSS_STATUS_UNAVAIL;
  63
  64   /* Find the netgroups file and open it.  */
  65   fp = fopen (DATAFILE, "rce");
  66   if (fp == NULL)
  67     status = errno == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
  68   else
  69     {
  70       /* Read the file line by line and try to find the description
  71          GROUP.  We must take care for long lines.  */
  72       char *line = NULL;
  73       size_t line_len = 0;
  74       const ssize_t group_len = strlen (group);
  75
  76       status = NSS_STATUS_NOTFOUND;
  77       result->cursor = result->data;
  78
  79       __fsetlocking (fp, FSETLOCKING_BYCALLER);
  80
  81       while (!feof_unlocked (fp))
  82         {
  83           ssize_t curlen = getline (&line, &line_len, fp);
  84           int found;
  85
  86           if (curlen < 0)
  87             {
  88               status = NSS_STATUS_NOTFOUND;
  89               break;
  90             }
  91
  92           found = (curlen > group_len && strncmp (line, group, group_len) == 0
  93                    && isspace (line[group_len]));
  94
  95           /* Read the whole line (including continuation) and store it
  96              if FOUND in nonzero.  Otherwise we don't need it.  */
  97           if (found)
  98             {
  99               /* Store the data from the first line.  */
 100               EXPAND (curlen - group_len);
 101               memcpy (result->cursor, &line[group_len + 1],
 102                       curlen - group_len);
 103               result->cursor += (curlen - group_len) - 1;
 104             }
 105
 106           while (line[curlen - 1] == '\n' && line[curlen - 2] == '\\')
 107             {
 108               /* Yes, we have a continuation line.  */
 109               if (found)
 110                 /* Remove these characters from the stored line.  */
 111                 result->cursor -= 2;
 112
 113               /* Get next line.  */
 114               curlen = getline (&line, &line_len, fp);
 115               if (curlen <= 0)
 116                 break;
 117
 118               if (found)
 119                 {
 120                   /* Make sure we have enough room.  */
 121                   EXPAND (1 + curlen + 1);
 122
 123                   /* Add separator in case next line starts immediately.  */
 124                   *result->cursor++ = ' ';
 125
 126                   /* Copy new line.  */
 127                   memcpy (result->cursor, line, curlen + 1);
 128                   result->cursor += curlen;
 129                 }
 130             }
 131
 132           if (found)
 133             {
 134               /* Now we have read the line.  */
 135               status = NSS_STATUS_SUCCESS;
 136               result->cursor = result->data;
 137               result->first = 1;
 138               break;
 139             }
 140         }
 141
 142     the_end:
 143       /* We don't need the file and the line buffer anymore.  */
 144       free (line);
 145       fclose (fp);
 146
 147       if (status != NSS_STATUS_SUCCESS)
 148         _nss_files_endnetgrent (result);
 149     }
 150
 151   return status;
 152 }
 153
 154
 155 enum nss_status
 156 _nss_files_endnetgrent (struct __netgrent *result)
 157 {
 158   /* Free allocated memory for data if some is present.  */
 159   free (result->data);
 160   result->data = NULL;
 161   result->data_size = 0;
 162   result->cursor = NULL;
 163   return NSS_STATUS_SUCCESS;
 164 }
 165 libnss_files_hidden_def (_nss_files_endnetgrent)
 166
 167 static char *
 168 strip_whitespace (char *str)
 169 {
 170   char *cp = str;
 171
 172   /* Skip leading spaces.  */
 173   while (isspace (*cp))
 174     cp++;
 175
 176   str = cp;
 177   while (*cp != '\0' && ! isspace(*cp))
 178     cp++;
 179
 180   /* Null-terminate, stripping off any trailing spaces.  */
 181   *cp = '\0';
 182
 183   return *str == '\0' ? NULL : str;
 184 }
 185
 186 enum nss_status
 187 _nss_netgroup_parseline (char **cursor, struct __netgrent *result,
 188                          char *buffer, size_t buflen, int *errnop)
 189 {
 190   enum nss_status status;
 191   const char *host, *user, *domain;
 192   char *cp = *cursor;
 193
 194   /* Some sanity checks.  */
 195   if (cp == NULL)
 196     return NSS_STATUS_NOTFOUND;
 197
 198   /* First skip leading spaces.  */
 199   while (isspace (*cp))
 200     ++cp;
 201
 202   if (*cp != '(')
 203     {
 204       /* We have a list of other netgroups.  */
 205       char *name = cp;
 206
 207       while (*cp != '\0' && ! isspace (*cp))
 208         ++cp;
 209
 210       if (name != cp)
 211         {
 212           /* It is another netgroup name.  */
 213           int last = *cp == '\0';
 214
 215           result->type = group_val;
 216           result->val.group = name;
 217           *cp = '\0';
 218           if (! last)
 219             ++cp;
 220           *cursor = cp;
 221           result->first = 0;
 222
 223           return NSS_STATUS_SUCCESS;
 224         }
 225
 226       return result->first ? NSS_STATUS_NOTFOUND : NSS_STATUS_RETURN;
 227     }
 228
 229   /* Match host name.  */
 230   host = ++cp;
 231   while (*cp != ',')
 232     if (*cp++ == '\0')
 233       return result->first ? NSS_STATUS_NOTFOUND : NSS_STATUS_RETURN;
 234
 235   /* Match user name.  */
 236   user = ++cp;
 237   while (*cp != ',')
 238     if (*cp++ == '\0')
 239       return result->first ? NSS_STATUS_NOTFOUND : NSS_STATUS_RETURN;
 240
 241   /* Match domain name.  */
 242   domain = ++cp;
 243   while (*cp != ')')
 244     if (*cp++ == '\0')
 245       return result->first ? NSS_STATUS_NOTFOUND : NSS_STATUS_RETURN;
 246   ++cp;
 247
 248
 249   /* When we got here we have found an entry.  Before we can copy it
 250      to the private buffer we have to make sure it is big enough.  */
 251   if (cp - host > buflen)
 252     {
 253       *errnop = ERANGE;
 254       status = NSS_STATUS_UNAVAIL;
 255     }
 256   else
 257     {
 258       memcpy (buffer, host, cp - host);
 259       result->type = triple_val;
 260
 261       buffer[(user - host) - 1] = '\0'; /* Replace ',' with '\0'.  */
 262       result->val.triple.host = strip_whitespace (buffer);
 263
 264       buffer[(domain - host) - 1] = '\0'; /* Replace ',' with '\0'.  */
 265       result->val.triple.user = strip_whitespace (buffer + (user - host));
 266
 267       buffer[(cp - host) - 1] = '\0'; /* Replace ')' with '\0'.  */
 268       result->val.triple.domain = strip_whitespace (buffer + (domain - host));
 269
 270       status = NSS_STATUS_SUCCESS;
 271
 272       /* Remember where we stopped reading.  */
 273       *cursor = cp;
 274
 275       result->first = 0;
 276     }
 277
 278   return status;
 279 }
 280 libnss_files_hidden_def (_nss_netgroup_parseline)
 281
 282
 283 enum nss_status
 284 _nss_files_getnetgrent_r (struct __netgrent *result, char *buffer,
 285                           size_t buflen, int *errnop)
 286 {
 287   enum nss_status status;
 288
 289   status = _nss_netgroup_parseline (&result->cursor, result, buffer, buflen,
 290                                     errnop);
 291
 292   return status;
 293 }