[Spice-devel] [PATCH spice-protocol] stream-device: Force proper packing of protocol structures

Frediano Ziglio fziglio at redhat.com
Wed Mar 7 11:08:58 UTC 2018


Assuming the packing of structure can be a portability issue.
Currently there are no real-world ABI that would break these structure
however to be safe force a 4 byte packing.

Signed-off-by: Frediano Ziglio <fziglio at redhat.com>
---
 spice/Makefile.am     |  2 ++
 spice/end-packed4.h   | 38 ++++++++++++++++++++++++++++++
 spice/start-packed4.h | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++
 spice/stream-device.h |  4 ++++
 4 files changed, 108 insertions(+)
 create mode 100644 spice/end-packed4.h
 create mode 100644 spice/start-packed4.h

diff --git a/spice/Makefile.am b/spice/Makefile.am
index 4f9a607..1b48d30 100644
--- a/spice/Makefile.am
+++ b/spice/Makefile.am
@@ -6,6 +6,7 @@ spice_protocol_include_HEADERS =		\
 	barrier.h				\
 	controller_prot.h			\
 	end-packed.h				\
+	end-packed4.h				\
 	enums.h					\
 	error_codes.h				\
 	foreign_menu_prot.h			\
@@ -15,6 +16,7 @@ spice_protocol_include_HEADERS =		\
 	qxl_dev.h				\
 	qxl_windows.h				\
 	start-packed.h				\
+	start-packed4.h				\
 	stats.h					\
 	types.h					\
 	vd_agent.h				\
diff --git a/spice/end-packed4.h b/spice/end-packed4.h
new file mode 100644
index 0000000..648370b
--- /dev/null
+++ b/spice/end-packed4.h
@@ -0,0 +1,38 @@
+/* -*- Mode: C; tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*- */
+/*
+   Copyright (C) 2009-2018 Red Hat, Inc.
+
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions are
+   met:
+
+       * Redistributions of source code must retain the above copyright
+         notice, this list of conditions and the following disclaimer.
+       * Redistributions in binary form must reproduce the above copyright
+         notice, this list of conditions and the following disclaimer in
+         the documentation and/or other materials provided with the
+         distribution.
+       * Neither the name of the copyright holder nor the names of its
+         contributors may be used to endorse or promote products derived
+         from this software without specific prior written permission.
+
+   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS "AS
+   IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+   TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+   PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+   HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/* See start-packed4.h for details */
+
+#undef SPICE_ATTR_PACKED4
+
+#if defined(__MINGW32__) || !defined(__GNUC__)
+#pragma pack(pop)
+#endif
diff --git a/spice/start-packed4.h b/spice/start-packed4.h
new file mode 100644
index 0000000..a402c64
--- /dev/null
+++ b/spice/start-packed4.h
@@ -0,0 +1,64 @@
+/* -*- Mode: C; tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*- */
+/*
+   Copyright (C) 2009-2018 Red Hat, Inc.
+
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions are
+   met:
+
+       * Redistributions of source code must retain the above copyright
+         notice, this list of conditions and the following disclaimer.
+       * Redistributions in binary form must reproduce the above copyright
+         notice, this list of conditions and the following disclaimer in
+         the documentation and/or other materials provided with the
+         distribution.
+       * Neither the name of the copyright holder nor the names of its
+         contributors may be used to endorse or promote products derived
+         from this software without specific prior written permission.
+
+   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS "AS
+   IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+   TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+   PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+   HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/* Ideally this should all have been macros in a common headers, but
+ * its not possible to put pragmas into header files, so we have
+ * to use include magic.
+ *
+ * Use it like this:
+ *
+ * #include <spice/start-packed4.h>
+ *
+ * typedef struct SPICE_ATTR_PACKED4 {
+ *    ...
+ * } Type;
+ *
+ * #include <spice/end-packed4.h>
+ *
+ */
+
+#ifdef __GNUC__
+
+#define SPICE_ATTR_PACKED4 __attribute__ ((__packed__, __aligned__(4)))
+
+#ifdef __MINGW32__
+#pragma pack(push,4)
+#endif
+
+#else
+
+#pragma pack(push)
+#pragma pack(4)
+#define SPICE_ATTR_PACKED4
+#pragma warning(disable:4200)
+#pragma warning(disable:4103)
+
+#endif
diff --git a/spice/stream-device.h b/spice/stream-device.h
index 2e7c50e..e72a675 100644
--- a/spice/stream-device.h
+++ b/spice/stream-device.h
@@ -43,6 +43,8 @@
 
 #include <spice/types.h>
 
+#include <spice/start-packed4.h>
+
 /*
  * Structures are all "naturally aligned"
  * containing integers up to 64 bit.
@@ -210,4 +212,6 @@ typedef struct StreamMsgCursorMove {
     int32_t y;
 } StreamMsgCursorMove;
 
+#include <spice/end-packed4.h>
+
 #endif /* SPICE_STREAM_DEVICE_H_ */
-- 
2.14.3



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