nbd: Don't take address of fields in packed structs

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.

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 <peter.maydell@linaro.org>
Message-Id: <20180927164200.15097-1-peter.maydell@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: rebase, and squash in missed changes]
Signed-off-by: Eric Blake <eblake@redhat.com>

1 files changed, 22 insertions, 22 deletions

diff --git a/nbd/client.c b/nbd/client.c
index 40b74d9..b4d457a 100644
--- a/nbd/client.c
+++ b/nbd/client.c
@@ -117,10 +117,10 @@ static int nbd_receive_option_reply(QIOChannel *ioc, uint32_t opt,
         nbd_send_opt_abort(ioc);
         return -1;
     }
-    be64_to_cpus(&reply->magic);
-    be32_to_cpus(&reply->option);
-    be32_to_cpus(&reply->type);
-    be32_to_cpus(&reply->length);
+    reply->magic = be64_to_cpu(reply->magic);
+    reply->option = be32_to_cpu(reply->option);
+    reply->type = be32_to_cpu(reply->type);
+    reply->length = be32_to_cpu(reply->length);
 
     trace_nbd_receive_option_reply(reply->option, nbd_opt_lookup(reply->option),
                                    reply->type, nbd_rep_lookup(reply->type),
@@ -396,7 +396,7 @@ static int nbd_opt_go(QIOChannel *ioc, const char *wantname,
             return -1;
         }
         len -= sizeof(type);
-        be16_to_cpus(&type);
+        type = be16_to_cpu(type);
         switch (type) {
         case NBD_INFO_EXPORT:
             if (len != sizeof(info->size) + sizeof(info->flags)) {
@@ -410,13 +410,13 @@ static int nbd_opt_go(QIOChannel *ioc, const char *wantname,
                 nbd_send_opt_abort(ioc);
                 return -1;
             }
-            be64_to_cpus(&info->size);
+            info->size = be64_to_cpu(info->size);
             if (nbd_read(ioc, &info->flags, sizeof(info->flags), errp) < 0) {
                 error_prepend(errp, "failed to read info flags: ");
                 nbd_send_opt_abort(ioc);
                 return -1;
             }
-            be16_to_cpus(&info->flags);
+            info->flags = be16_to_cpu(info->flags);
             trace_nbd_receive_negotiate_size_flags(info->size, info->flags);
             break;
 
@@ -433,7 +433,7 @@ static int nbd_opt_go(QIOChannel *ioc, const char *wantname,
                 nbd_send_opt_abort(ioc);
                 return -1;
             }
-            be32_to_cpus(&info->min_block);
+            info->min_block = be32_to_cpu(info->min_block);
             if (!is_power_of_2(info->min_block)) {
                 error_setg(errp, "server minimum block size %" PRIu32
                            " is not a power of two", info->min_block);
@@ -447,7 +447,7 @@ static int nbd_opt_go(QIOChannel *ioc, const char *wantname,
                 nbd_send_opt_abort(ioc);
                 return -1;
             }
-            be32_to_cpus(&info->opt_block);
+            info->opt_block = be32_to_cpu(info->opt_block);
             if (!is_power_of_2(info->opt_block) ||
                 info->opt_block < info->min_block) {
                 error_setg(errp, "server preferred block size %" PRIu32
@@ -461,7 +461,7 @@ static int nbd_opt_go(QIOChannel *ioc, const char *wantname,
                 nbd_send_opt_abort(ioc);
                 return -1;
             }
-            be32_to_cpus(&info->max_block);
+            info->max_block = be32_to_cpu(info->max_block);
             if (info->max_block < info->min_block) {
                 error_setg(errp, "server maximum block size %" PRIu32
                            " is not valid", info->max_block);
@@ -668,7 +668,7 @@ static int nbd_negotiate_simple_meta_context(QIOChannel *ioc,
         if (nbd_read(ioc, &received_id, sizeof(received_id), errp) < 0) {
             return -1;
         }
-        be32_to_cpus(&received_id);
+        received_id = be32_to_cpu(received_id);
 
         reply.length -= sizeof(received_id);
         name = g_malloc(reply.length + 1);
@@ -872,13 +872,13 @@ int nbd_receive_negotiate(QIOChannel *ioc, const char *name,
             error_prepend(errp, "Failed to read export length: ");
             goto fail;
         }
-        be64_to_cpus(&info->size);
+        info->size = be64_to_cpu(info->size);
 
         if (nbd_read(ioc, &info->flags, sizeof(info->flags), errp) < 0) {
             error_prepend(errp, "Failed to read export flags: ");
             goto fail;
         }
-        be16_to_cpus(&info->flags);
+        info->flags = be16_to_cpu(info->flags);
     } else if (magic == NBD_CLIENT_MAGIC) {
         uint32_t oldflags;
 
@@ -895,13 +895,13 @@ int nbd_receive_negotiate(QIOChannel *ioc, const char *name,
             error_prepend(errp, "Failed to read export length: ");
             goto fail;
         }
-        be64_to_cpus(&info->size);
+        info->size = be64_to_cpu(info->size);
 
         if (nbd_read(ioc, &oldflags, sizeof(oldflags), errp) < 0) {
             error_prepend(errp, "Failed to read export flags: ");
             goto fail;
         }
-        be32_to_cpus(&oldflags);
+        oldflags = be32_to_cpu(oldflags);
         if (oldflags & ~0xffff) {
             error_setg(errp, "Unexpected export flags %0x" PRIx32, oldflags);
             goto fail;
@@ -1080,8 +1080,8 @@ static int nbd_receive_simple_reply(QIOChannel *ioc, NBDSimpleReply *reply,
         return ret;
     }
 
-    be32_to_cpus(&reply->error);
-    be64_to_cpus(&reply->handle);
+    reply->error = be32_to_cpu(reply->error);
+    reply->handle = be64_to_cpu(reply->handle);
 
     return 0;
 }
@@ -1105,10 +1105,10 @@ static int nbd_receive_structured_reply_chunk(QIOChannel *ioc,
         return ret;
     }
 
-    be16_to_cpus(&chunk->flags);
-    be16_to_cpus(&chunk->type);
-    be64_to_cpus(&chunk->handle);
-    be32_to_cpus(&chunk->length);
+    chunk->flags = be16_to_cpu(chunk->flags);
+    chunk->type = be16_to_cpu(chunk->type);
+    chunk->handle = be64_to_cpu(chunk->handle);
+    chunk->length = be32_to_cpu(chunk->length);
 
     return 0;
 }
@@ -1128,7 +1128,7 @@ int nbd_receive_reply(QIOChannel *ioc, NBDReply *reply, Error **errp)
         return ret;
     }
 
-    be32_to_cpus(&reply->magic);
+    reply->magic = be32_to_cpu(reply->magic);
 
     switch (reply->magic) {
     case NBD_SIMPLE_REPLY_MAGIC: