glibc/support/support_format_hostent.c

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/* Convert a struct hostent object to a string.
Copyright (C) 2016-2019 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;
}