From: Nikolaus Rath <Nikolaus@rath.org>
Date: Thu, 12 Jan 2017 23:17:54 +0000 (-0800)
Subject: Replaced evil pointer magic with offsetof()
X-Git-Tag: fuse-3.0.1~37
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=3006686b536942f6f96675e3d12b793087e78e6a;p=qemu-gpiodev%2Flibfuse.git

Replaced evil pointer magic with offsetof()

This triggered undefined behaviour warnings from UBSan.
---

diff --git a/example/cuse.c b/example/cuse.c
index 15e2d37..cfbf753 100644
--- a/example/cuse.c
+++ b/example/cuse.c
@@ -141,11 +141,11 @@ static void fioc_do_rw(fuse_req_t req, void *addr, const void *in_buf,
 
 	/* prepare size outputs */
 	out_iov[0].iov_base =
-		addr + (unsigned long)&(((struct fioc_rw_arg *)0)->prev_size);
+		addr + offsetof(struct fioc_rw_arg, prev_size);
 	out_iov[0].iov_len = sizeof(arg->prev_size);
 
 	out_iov[1].iov_base =
-		addr + (unsigned long)&(((struct fioc_rw_arg *)0)->new_size);
+		addr + offsetof(struct fioc_rw_arg, new_size);
 	out_iov[1].iov_len = sizeof(arg->new_size);
 
 	/* prepare client buf */