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-rw-r--r--inet/ether_ntoh.c85
1 files changed, 85 insertions, 0 deletions
diff --git a/inet/ether_ntoh.c b/inet/ether_ntoh.c
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+/* Copyright (C) 1996 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 Library General Public License as
+published by the Free Software Foundation; either version 2 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
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+Boston, MA 02111-1307, USA.  */
+
+#include <netinet/ether.h>
+#include <netinet/if_ether.h>
+
+#include "../nss/nsswitch.h"
+
+/* Because the `ethers' lookup does not fit so well in the scheme so
+   we define a dummy struct here which helps us to use the available
+   functions.  */
+struct etherent
+{
+  const char *e_name;
+  struct ether_addr e_addr;
+};
+
+
+/* Type of the lookup function we need here.  */
+typedef int (*lookup_function) (const struct ether_addr *, struct etherent *,
+				char *, int);
+
+
+int
+ether_ntohost (char *hostname, const struct ether_addr *addr)
+{
+  static service_user *startp = NULL;
+  static lookup_function start_fct;
+  service_user *nip;
+  lookup_function fct;
+  int no_more;
+  int result;
+  enum nss_status status = NSS_STATUS_UNAVAIL;
+  struct etherent etherent;
+
+  if (startp == NULL)
+    {
+      no_more = __nss_ethers_lookup (&nip, "getntohost_r", (void **) &fct);
+      if (no_more)
+	startp = (service_user *) -1;
+      else
+	{
+	  startp = nip;
+	  start_fct = fct;
+	}
+    }
+  else
+    {
+      fct = start_fct;
+      no_more = (nip = startp) == (service_user *) -1;
+    }
+
+  while (no_more == 0)
+    {
+      char buffer[1024];
+
+      status = (*fct) (addr, &etherent, buffer, sizeof buffer);
+
+      no_more = __nss_next (&nip, "getntohost_r", (void **) &fct, 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;
+}