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[glibc.git] / inet / ether_ntoh.c
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1 /* Copyright (C) 1996, 1997, 1999, 2001, 2002 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
18 02111-1307 USA. */
20 #include <errno.h>
21 #include <netinet/ether.h>
22 #include <netinet/if_ether.h>
23 #include <string.h>
25 #include <nss/nsswitch.h>
28 /* Type of the lookup function we need here. */
29 typedef int (*lookup_function) (const struct ether_addr *, struct etherent *,
30 char *, size_t, int *);
32 /* The lookup function for the first entry of this service. */
33 extern int __nss_ethers_lookup (service_user **nip, const char *name,
34 void **fctp) internal_function;
37 int
38 ether_ntohost (char *hostname, const struct ether_addr *addr)
40 static service_user *startp;
41 static lookup_function start_fct;
42 service_user *nip;
43 lookup_function fct;
44 int no_more;
45 enum nss_status status = NSS_STATUS_UNAVAIL;
46 struct etherent etherent;
48 if (startp == NULL)
50 no_more = __nss_ethers_lookup (&nip, "getntohost_r", (void **) &fct);
51 if (no_more)
52 startp = (service_user *) -1;
53 else
55 startp = nip;
56 start_fct = fct;
59 else
61 fct = start_fct;
62 no_more = (nip = startp) == (service_user *) -1;
65 while (no_more == 0)
67 char buffer[1024];
69 status = (*fct) (addr, &etherent, buffer, sizeof buffer, &errno);
71 no_more = __nss_next (&nip, "getntohost_r", (void **) &fct, status, 0);
74 if (status == NSS_STATUS_SUCCESS)
75 /* XXX This is a potential cause of trouble because the size of
76 the HOSTNAME buffer is not known but the interface does not
77 provide this information. */
78 strcpy (hostname, etherent.e_name);
80 return status == NSS_STATUS_SUCCESS ? 0 : -1;