/* Convert a struct hostent object to a string.

   Copyright (C) 2016-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <support/format_nss.h>

#include <arpa/inet.h>

#include <errno.h>

#include <stdio.h>

#include <stdlib.h>

#include <support/support.h>

#include <support/xmemstream.h>

static int

address_length (int family)

{

  switch (family)

    {

    case AF_INET:

      return 4;

    case AF_INET6:

      return 16;

    }

  return -1;

}

char *

support_format_hostent (struct hostent *h)

{

  if (h == NULL)

    {

      if (h_errno == NETDB_INTERNAL)

        return xasprintf ("error: NETDB_INTERNAL (errno %d, %m)\n", errno);

      else

        {

          char *value = support_format_herrno (h_errno);

          char *result = xasprintf ("error: %s\n", value);

          free (value);

          return result;

        }

    }

  struct xmemstream mem;

  xopen_memstream (&mem;;

  fprintf (mem.out, "name: %s\n", h->h_name);

  for (char **alias = h->h_aliases; *alias != NULL; ++alias)

    fprintf (mem.out, "alias: %s\n", *alias);

  for (unsigned i = 0; h->h_addr_list[i] != NULL; ++i)

    {

      char buf[128];

      if (inet_ntop (h->h_addrtype, h->h_addr_list[i],

                     buf, sizeof (buf)) == NULL)

        fprintf (mem.out, "error: inet_ntop failed: %m\n");

      else

        fprintf (mem.out, "address: %s\n", buf);

    }

  if (h->h_length != address_length (h->h_addrtype))

    {

      char *family = support_format_address_family (h->h_addrtype);

      fprintf (mem.out, "error: invalid address length %d for %s\n",

               h->h_length, family);

      free (family);

    }

  xfclose_memstream (&mem;;

  return mem.buffer;

}