console: add Name function

when sending the console over i.e. (unix.Sendfd in runc), we also use name as
auxiliary data in the payload. This exposes `Name()` function. I think this
should be enough, maybe a bit leaner than exposing `File`

For windows, name is an empty string. Not sure if this is correct but i dont
know what are other options.

Signed-off-by: Daniel Dao <[email protected]>

Author: dqminh

console.go

@@ -28,6 +28,8 @@ type Console interface {
 	Size() (WinSize, error)
 	// Fd returns the console's file descriptor
 	Fd() uintptr
+	// Name returns the console's file name
+	Name() string
 }
 
 // WinSize specifies the window size of the console

console_unix.go

@@ -118,6 +118,10 @@ func (m *master) Fd() uintptr {
 	return m.f.Fd()
 }
 
+func (m *master) Name() string {
+	return m.f.Name()
+}
+
 // checkConsole checks if the provided file is a console
 func checkConsole(f *os.File) error {
 	var termios unix.Termios

console_windows.go

@@ -154,6 +154,13 @@ func (m *master) Fd() uintptr {
 	return m.in
 }
 
+// on windows, console can only be made from os.Std{in,out,err}, hence there
+// isnt a single name here we can use. Return a dummy "console" value in this
+// case should be sufficient.
+func (m *master) Name() string {
+	return "console"
+}
+
 // makeInputRaw puts the terminal (Windows Console) connected to the given
 // file descriptor into raw mode
 func makeInputRaw(fd uintptr, mode uint32) error {