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[Qemu-devel] [PATCH 2/3] block/qcow: Don't take address of fields in pac
From: |
Peter Maydell |
Subject: |
[Qemu-devel] [PATCH 2/3] block/qcow: Don't take address of fields in packed structs |
Date: |
Tue, 9 Oct 2018 18:25:00 +0100 |
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.
This patch was produced with the following spatch script:
@@
expression E;
@@
-be16_to_cpus(&E);
+E = be16_to_cpu(E);
@@
expression E;
@@
-be32_to_cpus(&E);
+E = be32_to_cpu(E);
@@
expression E;
@@
-be64_to_cpus(&E);
+E = be64_to_cpu(E);
@@
expression E;
@@
-cpu_to_be16s(&E);
+E = cpu_to_be16(E);
@@
expression E;
@@
-cpu_to_be32s(&E);
+E = cpu_to_be32(E);
@@
expression E;
@@
-cpu_to_be64s(&E);
+E = cpu_to_be64(E);
Signed-off-by: Peter Maydell <address@hidden>
---
block/qcow.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/block/qcow.c b/block/qcow.c
index 385d935258f..4518cb4c35e 100644
--- a/block/qcow.c
+++ b/block/qcow.c
@@ -140,14 +140,14 @@ static int qcow_open(BlockDriverState *bs, QDict
*options, int flags,
if (ret < 0) {
goto fail;
}
- be32_to_cpus(&header.magic);
- be32_to_cpus(&header.version);
- be64_to_cpus(&header.backing_file_offset);
- be32_to_cpus(&header.backing_file_size);
- be32_to_cpus(&header.mtime);
- be64_to_cpus(&header.size);
- be32_to_cpus(&header.crypt_method);
- be64_to_cpus(&header.l1_table_offset);
+ header.magic = be32_to_cpu(header.magic);
+ header.version = be32_to_cpu(header.version);
+ header.backing_file_offset = be64_to_cpu(header.backing_file_offset);
+ header.backing_file_size = be32_to_cpu(header.backing_file_size);
+ header.mtime = be32_to_cpu(header.mtime);
+ header.size = be64_to_cpu(header.size);
+ header.crypt_method = be32_to_cpu(header.crypt_method);
+ header.l1_table_offset = be64_to_cpu(header.l1_table_offset);
if (header.magic != QCOW_MAGIC) {
error_setg(errp, "Image not in qcow format");
@@ -270,7 +270,7 @@ static int qcow_open(BlockDriverState *bs, QDict *options,
int flags,
}
for(i = 0;i < s->l1_size; i++) {
- be64_to_cpus(&s->l1_table[i]);
+ s->l1_table[i] = be64_to_cpu(s->l1_table[i]);
}
/* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */
--
2.19.0
- [Qemu-devel] [PATCH 0/3] block/qcow*: Don't take address of fields in packed structs, Peter Maydell, 2018/10/09
- [Qemu-devel] [PATCH 2/3] block/qcow: Don't take address of fields in packed structs,
Peter Maydell <=
- [Qemu-devel] [PATCH 3/3] block/qcow2-bitmap: Don't take address of fields in packed structs, Peter Maydell, 2018/10/09
- [Qemu-devel] [PATCH 1/3] block/qcow2: Don't take address of fields in packed structs, Peter Maydell, 2018/10/09
- Re: [Qemu-devel] [PATCH 0/3] block/qcow*: Don't take address of fields in packed structs, Richard Henderson, 2018/10/09
- Re: [Qemu-devel] [Qemu-block] [PATCH 0/3] block/qcow*: Don't take address of fields in packed structs, John Snow, 2018/10/09
- Re: [Qemu-devel] [PATCH 0/3] block/qcow*: Don't take address of fields in packed structs, Kevin Wolf, 2018/10/10