Windows: Impl pkg\parsers kernel+os

Signed-off-by: John Howard <jhoward@microsoft.com>

parsers/kernel/kernel_windows.go

@@ -0,0 +1,65 @@
+package kernel
+
+import (
+	"fmt"
+	"syscall"
+	"unsafe"
+)
+
+type KernelVersionInfo struct {
+	kvi   string
+	major int
+	minor int
+	build int
+}
+
+func (k *KernelVersionInfo) String() string {
+	return fmt.Sprintf("%d.%d %d (%s)", k.major, k.minor, k.build, k.kvi)
+}
+
+func GetKernelVersion() (*KernelVersionInfo, error) {
+
+	var (
+		h         syscall.Handle
+		dwVersion uint32
+		err       error
+	)
+
+	KVI := &KernelVersionInfo{"Unknown", 0, 0, 0}
+
+	if err = syscall.RegOpenKeyEx(syscall.HKEY_LOCAL_MACHINE,
+		syscall.StringToUTF16Ptr(`SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\`),
+		0,
+		syscall.KEY_READ,
+		&h); err != nil {
+		return KVI, err
+	}
+	defer syscall.RegCloseKey(h)
+
+	var buf [1 << 10]uint16
+	var typ uint32
+	n := uint32(len(buf) * 2) // api expects array of bytes, not uint16
+
+	if err = syscall.RegQueryValueEx(h,
+		syscall.StringToUTF16Ptr("BuildLabEx"),
+		nil,
+		&typ,
+		(*byte)(unsafe.Pointer(&buf[0])),
+		&n); err != nil {
+		return KVI, err
+	}
+
+	KVI.kvi = syscall.UTF16ToString(buf[:])
+
+	// Important - docker.exe MUST be manifested for this API to return
+	// the correct information.
+	if dwVersion, err = syscall.GetVersion(); err != nil {
+		return KVI, err
+	}
+
+	KVI.major = int(dwVersion & 0xFF)
+	KVI.minor = int((dwVersion & 0XFF00) >> 8)
+	KVI.build = int((dwVersion & 0xFFFF0000) >> 16)
+
+	return KVI, nil
+}