[Qemu-devel] [PATCH 1/2] qga: add windows implementation for guest-get-time

[lilei@linux.vnet.ibm.com]

From: Lei Li <lilei@linux.vnet.ibm.com>

Signed-off-by: Lei Li <lilei@linux.vnet.ibm.com>
---
 qga/commands-win32.c |   32 ++++++++++++++++++++++++++++++++
 1 files changed, 32 insertions(+), 0 deletions(-)

diff --git a/qga/commands-win32.c b/qga/commands-win32.c
index 7e8ecb3..0a2bb34 100644
--- a/qga/commands-win32.c
+++ b/qga/commands-win32.c
@@ -22,6 +22,12 @@
 #define SHTDN_REASON_FLAG_PLANNED 0x80000000
 #endif
 
+/* multiple of 100 nanoseconds elapsed between windows baseline
+   (1/1/1601) and Unix Epoch (1/1/1970), accounting for leap years */
+#define W32_FT_OFFSET (10000000ULL * 60 * 60 * 24 * \
+                       (365 * (1970 - 1601) +       \
+                        (1970 - 1601) / 4 - 3))
+
 static void acquire_privilege(const char *name, Error **err)
 {
     HANDLE token;
@@ -108,6 +114,32 @@ void qmp_guest_shutdown(bool has_mode, const char *mode, Error **err)
     }
 }
 
+int64_t qmp_guest_get_time(Error **errp)
+{
+   SYSTEMTIME *ts = g_malloc0(sizeof(SYSTEMTIME));
+   int64_t time_ns;
+   union {
+       UINT64 ns100;
+       FILETIME tf;
+   } time;
+
+   GetSystemTime(ts);
+   if (!ts) {
+       slog("guest-get-time failed: %d", GetLastError());
+       error_setg_errno(errp, errno, "Failed to get time");
+       return -1;
+   }
+
+   if (!SystemTimeToFileTime(ts, &time.tf)) {
+       error_setg_errno(errp, errno, "Failed to convert system time");
+       return -1;
+   }
+
+   time_ns = (int64_t)((time.ns100 - W32_FT_OFFSET) * 100);
+
+   return time_ns;
+}
+
 int64_t qmp_guest_file_open(const char *path, bool has_mode, const char *mode, Error **err)
 {
     error_set(err, QERR_UNSUPPORTED);
-- 
1.7.7.6