1 files changed, 75 insertions, 0 deletions
diff --git a/support/support_format_hostent.c b/support/support_format_hostent.c
new file mode 100644
index 0000000000..5b5f26082e
--- /dev/null
+++ b/support/support_format_hostent.c
@@ -0,0 +1,75 @@
+/* Convert a struct hostent object to a string.
+   Copyright (C) 2016-2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <support/format_nss.h>
+
+#include <arpa/inet.h>
+#include <stdio.h>
+#include <support/support.h>
+#include <support/xmemstream.h>
+
+static int
+address_length (int family)
+{
+  switch (family)
+    {
+    case AF_INET:
+      return 4;
+    case AF_INET6:
+      return 16;
+    }
+  return -1;
+}
+
+char *
+support_format_hostent (struct hostent *h)
+{
+  if (h == NULL)
+    {
+      char *value = support_format_herrno (h_errno);
+      char *result = xasprintf ("error: %s\n", value);
+      free (value);
+      return result;
+    }
+
+  struct xmemstream mem;
+  xopen_memstream (&mem);
+
+  fprintf (mem.out, "name: %s\n", h->h_name);
+  for (char **alias = h->h_aliases; *alias != NULL; ++alias)
+    fprintf (mem.out, "alias: %s\n", *alias);
+  for (unsigned i = 0; h->h_addr_list[i] != NULL; ++i)
+    {
+      char buf[128];
+      if (inet_ntop (h->h_addrtype, h->h_addr_list[i],
+                     buf, sizeof (buf)) == NULL)
+        fprintf (mem.out, "error: inet_ntop failed: %m\n");
+      else
+        fprintf (mem.out, "address: %s\n", buf);
+    }
+  if (h->h_length != address_length (h->h_addrtype))
+    {
+      char *family = support_format_address_family (h->h_addrtype);
+      fprintf (mem.out, "error: invalid address length %d for %s\n",
+               h->h_length, family);
+      free (family);
+    }
+
+  xfclose_memstream (&mem);
+  return mem.buffer;
+}