Coccinelle: Add api/kstrdup.cocci

Use kstrdup rather than duplicating its implementation
Signed-off-by: Nicolas Palix <npalix@diku.dk>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Michal Marek <mmarek@suse.cz>

scripts/coccinelle/api/kstrdup.cocci

+/// Use kstrdup 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
+
+@@
+expression from,to;
+expression flag,E1,E2;
+statement S;
+@@
+
+-  to = kmalloc(strlen(from) + 1,flag);
++  to = kstrdup(from, flag);
+   ... when != \(from = E1 \| to = E1 \)
+   if (to==NULL || ...) S
+   ... when != \(from = E2 \| to = E2 \)
+-  strcpy(to, from);
+
+@@
+expression x,from,to;
+expression flag,E1,E2,E3;
+statement S;
+@@
+
+-   x = strlen(from) + 1;
+    ... when != \( x = E1 \| from = E1 \)
+-   to = \(kmalloc\|kzalloc\)(x,flag);
++   to = kstrdup(from, flag);
+    ... when != \(x = E2 \| from = E2 \| to = E2 \)
+    if (to==NULL || ...) S
+    ... when != \(x = E3 \| from = E3 \| to = E3 \)
+-   memcpy(to, from, x);