[Qemu-devel] [PULL 13/36] block/vdi: Don't take address of fields in packed structs

[Kevin Wolf <kwolf@redhat.com>]

From: Peter Maydell <peter.maydell@linaro.org>

Taking the address of a field in a packed struct is a bad idea, because
it might not be actually aligned enough for that pointer type (and
thus cause a crash on dereference on some host architectures). Newer
versions of clang warn about this. Avoid the bug by not using the
"modify in place" byte swapping functions.

There are a few places where the in-place swap function is
used on something other than a packed struct field; we convert
those anyway, for consistency.

Patch produced with scripts/coccinelle/inplace-byteswaps.cocci.

There are other places where we take the address of a packed member
in this file for other purposes than passing it to a byteswap
function (all the calls to qemu_uuid_*()); we leave those for now.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/vdi.c | 64 ++++++++++++++++++++++++++---------------------------
 1 file changed, 32 insertions(+), 32 deletions(-)

diff --git a/block/vdi.c b/block/vdi.c
index 6555cffb88..0ff1ead736 100644
--- a/block/vdi.c
+++ b/block/vdi.c
@@ -187,22 +187,22 @@ typedef struct {
 
 static void vdi_header_to_cpu(VdiHeader *header)
 {
-    le32_to_cpus(&header->signature);
-    le32_to_cpus(&header->version);
-    le32_to_cpus(&header->header_size);
-    le32_to_cpus(&header->image_type);
-    le32_to_cpus(&header->image_flags);
-    le32_to_cpus(&header->offset_bmap);
-    le32_to_cpus(&header->offset_data);
-    le32_to_cpus(&header->cylinders);
-    le32_to_cpus(&header->heads);
-    le32_to_cpus(&header->sectors);
-    le32_to_cpus(&header->sector_size);
-    le64_to_cpus(&header->disk_size);
-    le32_to_cpus(&header->block_size);
-    le32_to_cpus(&header->block_extra);
-    le32_to_cpus(&header->blocks_in_image);
-    le32_to_cpus(&header->blocks_allocated);
+    header->signature = le32_to_cpu(header->signature);
+    header->version = le32_to_cpu(header->version);
+    header->header_size = le32_to_cpu(header->header_size);
+    header->image_type = le32_to_cpu(header->image_type);
+    header->image_flags = le32_to_cpu(header->image_flags);
+    header->offset_bmap = le32_to_cpu(header->offset_bmap);
+    header->offset_data = le32_to_cpu(header->offset_data);
+    header->cylinders = le32_to_cpu(header->cylinders);
+    header->heads = le32_to_cpu(header->heads);
+    header->sectors = le32_to_cpu(header->sectors);
+    header->sector_size = le32_to_cpu(header->sector_size);
+    header->disk_size = le64_to_cpu(header->disk_size);
+    header->block_size = le32_to_cpu(header->block_size);
+    header->block_extra = le32_to_cpu(header->block_extra);
+    header->blocks_in_image = le32_to_cpu(header->blocks_in_image);
+    header->blocks_allocated = le32_to_cpu(header->blocks_allocated);
     qemu_uuid_bswap(&header->uuid_image);
     qemu_uuid_bswap(&header->uuid_last_snap);
     qemu_uuid_bswap(&header->uuid_link);
@@ -211,22 +211,22 @@ static void vdi_header_to_cpu(VdiHeader *header)
 
 static void vdi_header_to_le(VdiHeader *header)
 {
-    cpu_to_le32s(&header->signature);
-    cpu_to_le32s(&header->version);
-    cpu_to_le32s(&header->header_size);
-    cpu_to_le32s(&header->image_type);
-    cpu_to_le32s(&header->image_flags);
-    cpu_to_le32s(&header->offset_bmap);
-    cpu_to_le32s(&header->offset_data);
-    cpu_to_le32s(&header->cylinders);
-    cpu_to_le32s(&header->heads);
-    cpu_to_le32s(&header->sectors);
-    cpu_to_le32s(&header->sector_size);
-    cpu_to_le64s(&header->disk_size);
-    cpu_to_le32s(&header->block_size);
-    cpu_to_le32s(&header->block_extra);
-    cpu_to_le32s(&header->blocks_in_image);
-    cpu_to_le32s(&header->blocks_allocated);
+    header->signature = cpu_to_le32(header->signature);
+    header->version = cpu_to_le32(header->version);
+    header->header_size = cpu_to_le32(header->header_size);
+    header->image_type = cpu_to_le32(header->image_type);
+    header->image_flags = cpu_to_le32(header->image_flags);
+    header->offset_bmap = cpu_to_le32(header->offset_bmap);
+    header->offset_data = cpu_to_le32(header->offset_data);
+    header->cylinders = cpu_to_le32(header->cylinders);
+    header->heads = cpu_to_le32(header->heads);
+    header->sectors = cpu_to_le32(header->sectors);
+    header->sector_size = cpu_to_le32(header->sector_size);
+    header->disk_size = cpu_to_le64(header->disk_size);
+    header->block_size = cpu_to_le32(header->block_size);
+    header->block_extra = cpu_to_le32(header->block_extra);
+    header->blocks_in_image = cpu_to_le32(header->blocks_in_image);
+    header->blocks_allocated = cpu_to_le32(header->blocks_allocated);
     qemu_uuid_bswap(&header->uuid_image);
     qemu_uuid_bswap(&header->uuid_last_snap);
     qemu_uuid_bswap(&header->uuid_link);
-- 
2.19.1