90 lines
2.6 KiB
C
90 lines
2.6 KiB
C
/* Copyright (C) 1996, 1997, 1999 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 Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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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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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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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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/* Because the `ethers' lookup does not fit so well in the scheme so
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we define a dummy struct here which helps us to use the available
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functions. */
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struct etherent
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{
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const char *e_name;
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struct ether_addr e_addr;
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};
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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 *, int);
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/* The lookup function for the first entry of this service. */
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extern int __nss_ethers_lookup (service_user **nip, const char *name,
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void **fctp);
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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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lookup_function 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_lookup (&nip, "getntohost_r", (void **) &fct);
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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;
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}
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}
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else
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{
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fct = 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) (addr, ðerent, buffer, sizeof buffer);
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no_more = __nss_next (&nip, "getntohost_r", (void **) &fct, 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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