[Xen-devel] [PATCH v6 03/10] public: xen.h: add definitions for UUID handling

[Volodymyr Babchuk <volodymyr_babchuk@xxxxxxxx>]

Added type xen_uuid_t. This type represents UUID as an array of 16
bytes in big endian format.

Added macro XEN_DEFINE_UUID that constructs UUID in the usual way:

 XEN_DEFINE_UUID(0x00112233, 0x4455, 0x6677, 0x8899, 0xaabbccddeeff)

will construct UUID 00112233-4455-6677-8899-aabbccddeeff presented as
 {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88,
  0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff}

NB: This is compatible with Linux kernel and with libuuid, but it is not
compatible with Microsoft, as they use mixed-endian encoding (some
components are little-endian, some are big-endian).

Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@xxxxxxxx>
---

 * Fixed commit message (added 0x in XEN_DEFINE_UUID usage example)
 * As was agreed with Julien Grail ([1]), added two flavours of
   XEN_DEFINE_UUID(). One of them casts initialization list
   to right type (if compiler supports this), another - does not.

[1] http://markmail.org/message/cpced37242alfvz7
---
 xen/include/public/xen.h | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/xen/include/public/xen.h b/xen/include/public/xen.h
index 2ac6b1e..263bb3b 100644
--- a/xen/include/public/xen.h
+++ b/xen/include/public/xen.h
@@ -930,6 +930,33 @@ __DEFINE_XEN_GUEST_HANDLE(uint16, uint16_t);
 __DEFINE_XEN_GUEST_HANDLE(uint32, uint32_t);
 __DEFINE_XEN_GUEST_HANDLE(uint64, uint64_t);
 
+typedef struct
+{
+    uint8_t a[16];
+} xen_uuid_t;
+
+#if defined(__GNUC__) && !defined(__STRICT_ANSI__)
+
+#define XEN_DEFINE_UUID(a, b, c, d, e1, e2, e3, e4, e5, e6)             \
+    (xen_uuid_t){{((a) >> 24) & 0xFF, ((a) >> 16) & 0xFF,               \
+                  ((a) >>  8) & 0xFF, ((a) >>  0) & 0xFF,               \
+                  ((b) >>  8) & 0xFF, ((b) >>  0) & 0xFF,               \
+                  ((c) >>  8) & 0xFF, ((c) >>  0) & 0xFF,               \
+                  ((d) >>  8) & 0xFF, ((d) >>  0) & 0xFF,               \
+                           e1, e2, e3, e4, e5, e6}}
+
+#else
+
+#define XEN_DEFINE_UUID(a, b, c, d, e1, e2, e3, e4, e5, e6)             \
+    {{((a) >> 24) & 0xFF, ((a) >> 16) & 0xFF,                           \
+      ((a) >>  8) & 0xFF, ((a) >>  0) & 0xFF,                           \
+      ((b) >>  8) & 0xFF, ((b) >>  0) & 0xFF,                           \
+      ((c) >>  8) & 0xFF, ((c) >>  0) & 0xFF,                           \
+      ((d) >>  8) & 0xFF, ((d) >>  0) & 0xFF,                           \
+                e1, e2, e3, e4, e5, e6}}
+
+#endif /* (__GNUC__) && !defined(__STRICT_ANSI__) */
+
 #endif /* !__ASSEMBLY__ */
 
 /* Default definitions for macros used by domctl/sysctl. */
-- 
2.7.4


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