commit fbad2b61020cccb8afa26968690e02bb62d1cc78
Author: Justus Winter <4winter@informatik.uni-hamburg.de>
Date:   Fri Feb 21 21:57:37 2014 +0100

    kern: fix mig_strncpy
    
    Previously, the function mig_strncpy would always zero-terminate the
    destination string.  Make mig_strncpy behave like mig_strncpy and
    strncpy in the glibc.  Also fix the implementation of mig_strncpy to
    return the length of the written string to align the implementation
    with the declaration in include/mach/mig_support.h.
    
    * kern/ipc_mig.c (mig_strncpy): Do not zero-terminate the destination
    string.  Return length of destination string.

diff --git a/kern/ipc_mig.c b/kern/ipc_mig.c
index bbc38cf..a52dcb9 100644
--- a/kern/ipc_mig.c
+++ b/kern/ipc_mig.c
@@ -285,22 +285,23 @@ mig_put_reply_port(
  *
  *     len - Length of destination buffer.
  */
-void mig_strncpy(dest, src, len)
+vm_size_t
+mig_strncpy(dest, src, len)
 char *dest;
 const char *src;
 int len;
 {
+    char *dest_ = dest;
     int i;
 
     if (len <= 0)
-	return;
+	return 0;
 
-    for (i=1; i<len; i++)
+    for (i=0; i<len; i++)
 	if (! (*dest++ = *src++))
-	    return;
+	    break;
 
-    *dest = '\0';
-    return;
+    return dest - dest_;
 }
 
 #define	fast_send_right_lookup(name, port, abort)			\