hesiod/nss_hesiod/hesiod-service.c

   1 /* Copyright (C) 1997-2023 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, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <hesiod.h>
  20 #include <netdb.h>
  21 #include <netinet/in.h>
  22 #include <nss.h>
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26
  27 NSS_DECLARE_MODULE_FUNCTIONS (hesiod)
  28
  29 /* Hesiod uses a format for service entries that differs from the
  30    traditional format.  We therefore declare our own parser.  */
  31
  32 #define ENTNAME servent
  33
  34 struct servent_data {};
  35
  36 #define TRAILING_LIST_MEMBER            s_aliases
  37 #define TRAILING_LIST_SEPARATOR_P       isspace
  38 #include <nss/nss_files/files-parse.c>
  39 #define ISSC_OR_SPACE(c)        ((c) ==  ';' || isspace (c))
  40 LINE_PARSER
  41 ("#",
  42  STRING_FIELD (result->s_name, ISSC_OR_SPACE, 1);
  43  STRING_FIELD (result->s_proto, ISSC_OR_SPACE, 1);
  44  INT_FIELD (result->s_port, ISSC_OR_SPACE, 10, 0, htons);
  45  )
  46
  47 enum nss_status
  48 _nss_hesiod_setservent (int stayopen)
  49 {
  50   return NSS_STATUS_SUCCESS;
  51 }
  52
  53 enum nss_status
  54 _nss_hesiod_endservent (void)
  55 {
  56   return NSS_STATUS_SUCCESS;
  57 }
  58
  59 static enum nss_status
  60 lookup (const char *name, const char *type, const char *protocol,
  61         struct servent *serv, char *buffer, size_t buflen, int *errnop)
  62 {
  63   struct parser_data *data = (void *) buffer;
  64   size_t linebuflen;
  65   void *context;
  66   char **list, **item;
  67   int parse_res;
  68   int found;
  69   int olderr = errno;
  70
  71   if (hesiod_init (&context) < 0)
  72     return NSS_STATUS_UNAVAIL;
  73
  74   list = hesiod_resolve (context, name, type);
  75   if (list == NULL)
  76     {
  77       int err = errno;
  78       hesiod_end (context);
  79       __set_errno (olderr);
  80       return err == ENOENT ? NSS_STATUS_NOTFOUND : NSS_STATUS_UNAVAIL;
  81     }
  82
  83   linebuflen = buffer + buflen - data->linebuffer;
  84
  85   item = list;
  86   found = 0;
  87   do
  88     {
  89       size_t len = strlen (*item) + 1;
  90
  91       if (linebuflen < len)
  92         {
  93           hesiod_free_list (context, list);
  94           hesiod_end (context);
  95           *errnop = ERANGE;
  96           return NSS_STATUS_TRYAGAIN;
  97         }
  98
  99       memcpy (data->linebuffer, *item, len);
 100
 101       parse_res = parse_line (buffer, serv, data, buflen, errnop);
 102       if (parse_res == -1)
 103         {
 104           hesiod_free_list (context, list);
 105           hesiod_end (context);
 106           return NSS_STATUS_TRYAGAIN;
 107         }
 108
 109       if (parse_res > 0)
 110         found = protocol == NULL || strcasecmp (serv->s_proto, protocol) == 0;
 111
 112       ++item;
 113     }
 114   while (*item != NULL && !found);
 115
 116   hesiod_free_list (context, list);
 117   hesiod_end (context);
 118
 119   if (found == 0)
 120     {
 121       __set_errno (olderr);
 122       return NSS_STATUS_NOTFOUND;
 123     }
 124
 125   return NSS_STATUS_SUCCESS;
 126 }
 127
 128 enum nss_status
 129 _nss_hesiod_getservbyname_r (const char *name, const char *protocol,
 130                              struct servent *serv,
 131                              char *buffer, size_t buflen, int *errnop)
 132 {
 133   return lookup (name, "service", protocol, serv, buffer, buflen, errnop);
 134 }
 135
 136 enum nss_status
 137 _nss_hesiod_getservbyport_r (const int port, const char *protocol,
 138                              struct servent *serv,
 139                              char *buffer, size_t buflen, int *errnop)
 140 {
 141   char portstr[6];          /* Port numbers are restricted to 16 bits. */
 142
 143   snprintf (portstr, sizeof portstr, "%d", ntohs (port));
 144
 145   return lookup (portstr, "port", protocol, serv, buffer, buflen, errnop);
 146 }