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  }