nss/nss_db/db-netgrp.c

   1 /* Netgroup file parser in nss_db modules.
   2    Copyright (C) 1996-2022 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    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <ctype.h>
  20 #include <dlfcn.h>
  21 #include <errno.h>
  22 #include <fcntl.h>
  23 #include <netgroup.h>
  24 #include <string.h>
  25 #include <stdint.h>
  26 #include <libc-lock.h>
  27 #include <paths.h>
  28 #include <stdlib.h>
  29
  30 #include "nsswitch.h"
  31 #include "nss_db.h"
  32
  33 /* The hashing function we use.  */
  34 #include "../intl/hash-string.h"
  35
  36
  37 #define DBFILE          _PATH_VARDB "netgroup.db"
  38 \f
  39 /* Maintenance of the shared handle open on the database.  */
  40 enum nss_status
  41 _nss_db_setnetgrent (const char *group, struct __netgrent *result)
  42 {
  43   struct nss_db_map state;
  44   enum nss_status status = internal_setent (DBFILE, &state);
  45
  46   if (status == NSS_STATUS_SUCCESS)
  47     {
  48       const struct nss_db_header *header = state.header;
  49       const stridx_t *hashtable
  50         = (const stridx_t *) ((const char *) header
  51                               + header->dbs[0].hashoffset);
  52       const char *valstrtab = (const char *) header + header->valstroffset;
  53       uint32_t hashval = __hash_string (group);
  54       size_t grouplen = strlen (group);
  55       size_t hidx = hashval % header->dbs[0].hashsize;
  56       size_t hval2 = 1 + hashval % (header->dbs[0].hashsize - 2);
  57
  58       status = NSS_STATUS_NOTFOUND;
  59       while (hashtable[hidx] != ~((stridx_t) 0))
  60         {
  61           const char *valstr = valstrtab + hashtable[hidx];
  62
  63           if (strncmp (valstr, group, grouplen) == 0
  64               && isblank (valstr[grouplen]))
  65             {
  66               const char *cp = &valstr[grouplen + 1];
  67               while (isblank (*cp))
  68                 ++cp;
  69               if (*cp != '\0')
  70                 {
  71                   result->data = strdup (cp);
  72                   if (result->data == NULL)
  73                     status = NSS_STATUS_TRYAGAIN;
  74                   else
  75                     {
  76                       status = NSS_STATUS_SUCCESS;
  77                       result->cursor = result->data;
  78                     }
  79                   break;
  80                 }
  81             }
  82
  83           if ((hidx += hval2) >= header->dbs[0].hashsize)
  84             hidx -= header->dbs[0].hashsize;
  85         }
  86
  87       internal_endent (&state);
  88     }
  89
  90   return status;
  91
  92 }
  93
  94
  95 enum nss_status
  96 _nss_db_endnetgrent (struct __netgrent *result)
  97 {
  98   free (result->data);
  99   result->data = NULL;
 100   result->data_size = 0;
 101   result->cursor = NULL;
 102   return NSS_STATUS_SUCCESS;
 103 }
 104
 105
 106 extern enum nss_status _nss_netgroup_parseline (char **cursor,
 107                                                 struct __netgrent *result,
 108                                                 char *buffer, size_t buflen,
 109                                                 int *errnop);
 110
 111 enum nss_status
 112 _nss_db_getnetgrent_r (struct __netgrent *result, char *buffer, size_t buflen,
 113                        int *errnop)
 114 {
 115   enum nss_status status;
 116
 117   status = _nss_netgroup_parseline (&result->cursor, result, buffer, buflen,
 118                                     errnop);
 119
 120   return status;
 121 }