80 lines
2.2 KiB
C
80 lines
2.2 KiB
C
/* Copyright (C) 1996-2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <errno.h>
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#include <netinet/ether.h>
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#include <netinet/if_ether.h>
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#include <string.h>
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#include <nss/nsswitch.h>
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/* Type of the lookup function we need here. */
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typedef int (*lookup_function) (const struct ether_addr *, struct etherent *,
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char *, size_t, int *);
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int
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ether_ntohost (char *hostname, const struct ether_addr *addr)
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{
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static service_user *startp;
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static lookup_function start_fct;
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service_user *nip;
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union
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{
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lookup_function f;
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void *ptr;
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} fct;
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int no_more;
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enum nss_status status = NSS_STATUS_UNAVAIL;
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struct etherent etherent;
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if (startp == NULL)
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{
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no_more = __nss_ethers_lookup2 (&nip, "getntohost_r", NULL, &fct.ptr);
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if (no_more)
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startp = (service_user *) -1;
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else
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{
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startp = nip;
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start_fct = fct.f;
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}
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}
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else
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{
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fct.f = start_fct;
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no_more = (nip = startp) == (service_user *) -1;
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}
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while (no_more == 0)
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{
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char buffer[1024];
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status = (*fct.f) (addr, ðerent, buffer, sizeof buffer, &errno);
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no_more = __nss_next2 (&nip, "getntohost_r", NULL, &fct.ptr, status, 0);
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}
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if (status == NSS_STATUS_SUCCESS)
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/* XXX This is a potential cause of trouble because the size of
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the HOSTNAME buffer is not known but the interface does not
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provide this information. */
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strcpy (hostname, etherent.e_name);
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return status == NSS_STATUS_SUCCESS ? 0 : -1;
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}
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