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/* Copyright (C) 1996-2020 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
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
<https://www.gnu.org/licenses/>. */
#include <errno.h>
#include <netinet/ether.h>
#include <netinet/if_ether.h>
#include <string.h>
#include <nss/nsswitch.h>
/* Type of the lookup function we need here. */
typedef int (*lookup_function) (const struct ether_addr *, struct etherent *,
char *, size_t, int *);
int
ether_ntohost (char *hostname, const struct ether_addr *addr)
{
static service_user *startp;
static lookup_function start_fct;
service_user *nip;
union
{
lookup_function f;
void *ptr;
} fct;
int no_more;
enum nss_status status = NSS_STATUS_UNAVAIL;
struct etherent etherent;
if (startp == NULL)
{
no_more = __nss_ethers_lookup2 (&nip, "getntohost_r", NULL, &fct.ptr);
if (no_more)
startp = (service_user *) -1;
else
{
startp = nip;
start_fct = fct.f;
}
}
else
{
fct.f = start_fct;
no_more = (nip = startp) == (service_user *) -1;
}
while (no_more == 0)
{
char buffer[1024];
status = (*fct.f) (addr, ðerent, buffer, sizeof buffer, &errno);
no_more = __nss_next2 (&nip, "getntohost_r", NULL, &fct.ptr, status, 0);
}
if (status == NSS_STATUS_SUCCESS)
/* XXX This is a potential cause of trouble because the size of
the HOSTNAME buffer is not known but the interface does not
provide this information. */
strcpy (hostname, etherent.e_name);
return status == NSS_STATUS_SUCCESS ? 0 : -1;
}
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