From: Julien Grall <jgrall@amazon.com>
Date: Mon, 30 Mar 2020 13:29:10 +0000 (+0100)
Subject: tools/ocaml: libxb: Harden stub_header_of_string()
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=939164f40a9d060e086554e2d6d36346b9be7637;p=xen.git

tools/ocaml: libxb: Harden stub_header_of_string()

stub_header_of_string() should not modify the header. So mark the
variable 'hdr' as const.

Signed-off-by: Julien Grall <jgrall@amazon.com>
Acked-by: Christian Lindig <christian.lindig@citrix.com>
(cherry picked from commit d92ba1aa7cf877a77abdcbd94a6a19fc55886a75)
---

diff --git a/tools/ocaml/libs/xb/xenbus_stubs.c b/tools/ocaml/libs/xb/xenbus_stubs.c
index a68e783f70..001bb03371 100644
--- a/tools/ocaml/libs/xb/xenbus_stubs.c
+++ b/tools/ocaml/libs/xb/xenbus_stubs.c
@@ -40,12 +40,12 @@ CAMLprim value stub_header_of_string(value s)
 {
 	CAMLparam1(s);
 	CAMLlocal1(ret);
-	struct xsd_sockmsg *hdr;
+	const struct xsd_sockmsg *hdr;
 
 	if (caml_string_length(s) != sizeof(struct xsd_sockmsg))
 		caml_failwith("xb header incomplete");
 	ret = caml_alloc_tuple(4);
-	hdr = (struct xsd_sockmsg *) String_val(s);
+	hdr = (const struct xsd_sockmsg *) String_val(s);
 	Store_field(ret, 0, Val_int(hdr->tx_id));
 	Store_field(ret, 1, Val_int(hdr->req_id));
 	Store_field(ret, 2, Val_int(hdr->type));