bzr commit into mysql-5.0 branch (chad:2666) Bug#30394

[Chad MILLER]

#At file:///home/cmiller/work/mysqlbzr/mysql-5.0-bugteam/

 2666 Chad MILLER	2008-08-18
      Bug#30394: Empty HOME environment variable causes several utilities to crash
      
      Tilde expansion could fail when it was to expand to an empty string (such as
      when HOME is set to an empty string), especially on systems where size_t is
      unsigned.
modified:
  mysys/mf_pack.c

=== modified file 'mysys/mf_pack.c'
--- a/mysys/mf_pack.c	2008-07-16 22:58:45 +0000
+++ b/mysys/mf_pack.c	2008-08-18 17:06:27 +0000
@@ -343,7 +343,7 @@ uint unpack_dirname(my_string to, const 
       length-=(uint) (suffix-buff)-1;
       if (length+(h_length= (uint) strlen(tilde_expansion)) <= FN_REFLEN)
       {
-	if (tilde_expansion[h_length-1] == FN_LIBCHAR)
+	if ((h_length > 0) && (tilde_expansion[h_length-1] == FN_LIBCHAR))
 	  h_length--;
 	if (buff+h_length < suffix)
 	  bmove(buff+h_length,suffix,length);