Merge pull request #21272 from Microsoft/jstarks/manifest_updates

Add os_version and os_features to Image

system/syscall_windows.go

@@ -1,11 +1,14 @@
 package system
 
 import (
-	"fmt"
 	"syscall"
 	"unsafe"
 )
 
+var (
+	ntuserApiset = syscall.NewLazyDLL("ext-ms-win-ntuser-window-l1-1-0")
+)
+
 // OSVersion is a wrapper for Windows version information
 // https://msdn.microsoft.com/en-us/library/windows/desktop/ms724439(v=vs.85).aspx
 type OSVersion struct {
@@ -17,17 +20,18 @@ type OSVersion struct {
 
 // GetOSVersion gets the operating system version on Windows. Note that
 // docker.exe must be manifested to get the correct version information.
-func GetOSVersion() (OSVersion, error) {
+func GetOSVersion() OSVersion {
 	var err error
 	osv := OSVersion{}
 	osv.Version, err = syscall.GetVersion()
 	if err != nil {
-		return osv, fmt.Errorf("Failed to call GetVersion()")
+		// GetVersion never fails.
+		panic(err)
 	}
 	osv.MajorVersion = uint8(osv.Version & 0xFF)
 	osv.MinorVersion = uint8(osv.Version >> 8 & 0xFF)
 	osv.Build = uint16(osv.Version >> 16)
-	return osv, nil
+	return osv
 }
 
 // Unmount is a platform-specific helper function to call
@@ -58,3 +62,12 @@ func CommandLineToArgv(commandLine string) ([]string, error) {
 
 	return newArgs, nil
 }
+
+// HasWin32KSupport determines whether containers that depend on win32k can
+// run on this machine. Win32k is the driver used to implement windowing.
+func HasWin32KSupport() bool {
+	// For now, check for ntuser API support on the host. In the future, a host
+	// may support win32k in containers even if the host does not support ntuser
+	// APIs.
+	return ntuserApiset.Load() == nil
+}

system/syscall_windows_test.go

@@ -0,0 +1,9 @@
+package system
+
+import "testing"
+
+func TestHasWin32KSupport(t *testing.T) {
+	s := HasWin32KSupport() // make sure this doesn't panic
+
+	t.Logf("win32k: %v", s) // will be different on different platforms -- informative only
+}

term/term_windows.go

@@ -57,10 +57,7 @@ func StdStreams() (stdIn io.ReadCloser, stdOut, stdErr io.Writer) {
 // console which supports ANSI emulation, or fall-back to the golang emulator
 // (github.com/azure/go-ansiterm).
 func useNativeConsole() bool {
-	osv, err := system.GetOSVersion()
-	if err != nil {
-		return false
-	}
+	osv := system.GetOSVersion()
 
 	// Native console is not available before major version 10
 	if osv.MajorVersion < 10 {