/* Host name canonicalization
- Copyright (C) 1995, 1999 Free Software Foundation, Inc.
+ Copyright (C) 1995, 1999, 2000, 2002, 2003 Free Software Foundation, Inc.
Written by Miles Bader <miles@gnu.ai.mit.edu>
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif
-#ifdef HAVE_STRING_H
-# include <string.h>
-#endif
+#include <stdlib.h>
+#include <string.h>
#ifdef HAVE_NETDB_H
# include <netdb.h>
#endif
}
if (addr && strcmp (he->h_name, addr) == 0)
- /* gethostbyname() cheated! Lookup the host name via the address
- this time to get the actual host name. */
- he = gethostbyaddr (he->h_addr, he->h_length, he->h_addrtype);
+ {
+ /* gethostbyname has returned a string representation of the IP
+ address, for example, "127.0.0.1". So now, look up the host
+ name via the address. Although it may seem reasonable to look
+ up the host name via the address, we must not pass `he->h_addr'
+ directly to gethostbyaddr because on some systems he->h_addr
+ is located in a static library buffer that is reused in the
+ gethostbyaddr call. Make a copy and use that instead. */
+ char *h_addr_copy = (char *) malloc (he->h_length);
+ if (h_addr_copy == NULL)
+ he = NULL;
+ else
+ {
+ memcpy (h_addr_copy, he->h_addr, he->h_length);
+ he = gethostbyaddr (h_addr_copy, he->h_length, he->h_addrtype);
+ free (h_addr_copy);
+ }
+ }
# endif /* HAVE_GETHOSTBYADDR */
if (he)
#endif /* HAVE_GETHOSTBYNAME */
return 0;
}
+
+#ifdef TEST_CANON_HOST
+int
+main (int argc, char **argv)
+{
+ int i;
+ for (i = 1; i < argc; i++)
+ {
+ char *s = canon_host (argv[i]);
+ printf ("%s: %s\n", argv[i], (s ? s : "<undef>"));
+ }
+ exit (0);
+}
+#endif /* TEST_CANON_HOST */