Coccinelle: Add api/memdup.cocci

/// Use kmemdup rather than duplicating its implementation

///

// Confidence: High

// Copyright: (C) 2010 Nicolas Palix, DIKU.  GPLv2.

// Copyright: (C) 2010 Julia Lawall, DIKU.  GPLv2.

// Copyright: (C) 2010 Gilles Muller, INRIA/LiP6.  GPLv2.

// URL: http://coccinelle.lip6.fr/

// Comments:

// Options: -no_includes -include_headers

virtual patch

@r1@

expression from,to;

expression flag;

position p;

@@

   to = \(kmalloc@p\|kzalloc@p\)(strlen(from) + 1,flag);

@r2@

expression x,from,to;

expression flag,E1;

position p;

@@

    x = strlen(from) + 1;

    ... when != \( x = E1 \| from = E1 \)

    to = \(kmalloc@p\|kzalloc@p\)(x,flag);

@@

expression from,to,size,flag;

position p != {r1.p,r2.p};

statement S;

@@

-  to = \(kmalloc@p\|kzalloc@p\)(size,flag);

+  to = kmemdup(from,size,flag);

   if (to==NULL || ...) S

-  memcpy(to, from, size);