X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;ds=sidebyside;f=lib%2Fcanon-host.c;h=74c36f6f75b7bf11b07ac74c38ea4dc5bfc8efdd;hb=572993f926994346e843556b653b619b61a101c2;hp=1f6b575ee15d756272855d475c55cbd83dfe0879;hpb=eef6a0f21a7b5a7020a1fecd599b23838c469b61;p=gnulib.git

diff --git a/lib/canon-host.c b/lib/canon-host.c
index 1f6b575ee..74c36f6f7 100644
--- a/lib/canon-host.c
+++ b/lib/canon-host.c
@@ -1,6 +1,6 @@
 /* Host name canonicalization
 
-   Copyright (C) 1995, 1999 Free Software Foundation, Inc.
+   Copyright (C) 1995, 1999, 2000 Free Software Foundation, Inc.
 
    Written by Miles Bader <miles@gnu.ai.mit.edu>
 
@@ -26,6 +26,9 @@
 #ifdef HAVE_UNISTD_H
 # include <unistd.h>
 #endif
+#ifdef HAVE_STDLIB_H
+# include <stdlib.h>
+#endif
 #ifdef HAVE_STRING_H
 # include <string.h>
 #endif
@@ -43,6 +46,10 @@
 # include <arpa/inet.h>
 #endif
 
+#ifndef strdup
+char *strdup ();
+#endif
+
 /* Returns the canonical hostname associated with HOST (allocated in a static
    buffer), or 0 if it can't be determined.  */
 char *
@@ -67,9 +74,24 @@ canon_host (const char *host)
 	}
 
       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)