--- glibc-2.1.3/malloc/malloc.c.org	Wed Feb 23 08:02:55 2000
+++ glibc-2.1.3/malloc/malloc.c	Thu Jul  5 15:03:53 2001
@@ -2975,6 +2975,13 @@
 
 */
 
+/* for wiping free'd blocks with zeroes */
+#define SINA_MALLOC_WIPED_FREE	1
+
+
+#ifdef SINA_MALLOC_WIPED_FREE
+static char sinaoptions[] = "SINA_MALLOC_WIPED_FREE";
+#endif /* SINA_MALLOC_WIPED_FREE */  
 
 #if __STD_C
 void fREe(Void_t* mem)
@@ -2985,6 +2992,10 @@
   arena *ar_ptr;
   mchunkptr p;                          /* chunk corresponding to mem */
 
+#ifdef SINA_MALLOC_WIPED_FREE
+  INTERNAL_SIZE_T csz;
+#endif /* SINA_MALLOC_WIPED_FREE */  
+
 #if defined _LIBC || defined MALLOC_HOOKS
   if (__free_hook != NULL) {
 #if defined __GNUC__ && __GNUC__ >= 2
@@ -3020,6 +3031,21 @@
 #else
   (void)mutex_lock(&ar_ptr->mutex);
 #endif
+
+#ifdef SINA_MALLOC_WIPED_FREE
+    csz = chunksize(p);
+    /* size for zero should be only one minus, while the chunk is in use
+     * and therefor footer is not used;
+     * I hope so ;-|
+     */
+    
+    /*
+    fprintf(stderr, "wiped_free: clear chunk (addr: %x size: %d)\n", mem, csz-SIZE_SZ);
+    */
+    
+    MALLOC_ZERO(mem, csz - SIZE_SZ);
+#endif /* SINA_MALLOC_WIPED_FREE */ 
+
   chunk_free(ar_ptr, p);
   (void)mutex_unlock(&ar_ptr->mutex);
 }