libcontainer: use ioctl wrappers from x/sys/unix

Use IoctlGetInt and IoctlGetTermios/IoctlSetTermios instead of manually
reimplementing them.

Because of unlockpt, the ioctl wrapper is still needed as it needs to
pass a pointer to a value, which is not supported by any ioctl function
in x/sys/unix yet.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>

libcontainer/console_linux.go

@@ -123,8 +123,8 @@ func unlockpt(f *os.File) error {
 
 // ptsname retrieves the name of the first available pts for the given master.
 func ptsname(f *os.File) (string, error) {
-	var n int32
-	if err := ioctl(f.Fd(), unix.TIOCGPTN, uintptr(unsafe.Pointer(&n))); err != nil {
+	n, err := unix.IoctlGetInt(int(f.Fd()), unix.TIOCGPTN)
+	if err != nil {
 		return "", err
 	}
 	return fmt.Sprintf("/dev/pts/%d", n), nil
@@ -136,17 +136,15 @@ func ptsname(f *os.File) (string, error) {
 // problem for terminal emulators, because we relay data from the terminal we
 // also relay that funky line discipline.
 func SaneTerminal(terminal *os.File) error {
-	// Go doesn't have a wrapper for any of the termios ioctls.
-	var termios unix.Termios
-
-	if err := ioctl(terminal.Fd(), unix.TCGETS, uintptr(unsafe.Pointer(&termios))); err != nil {
+	termios, err := unix.IoctlGetTermios(int(terminal.Fd()), unix.TCGETS)
+	if err != nil {
 		return fmt.Errorf("ioctl(tty, tcgets): %s", err.Error())
 	}
 
 	// Set -onlcr so we don't have to deal with \r.
 	termios.Oflag &^= unix.ONLCR
 
-	if err := ioctl(terminal.Fd(), unix.TCSETS, uintptr(unsafe.Pointer(&termios))); err != nil {
+	if err := unix.IoctlSetTermios(int(terminal.Fd()), unix.TCSETS, termios); err != nil {
 		return fmt.Errorf("ioctl(tty, tcsets): %s", err.Error())
 	}
 

libcontainer/system/linux.go

@@ -95,7 +95,7 @@ func ClearKeepCaps() error {
 }
 
 func Setctty() error {
-	if _, _, err := unix.RawSyscall(unix.SYS_IOCTL, 0, uintptr(unix.TIOCSCTTY), 0); err != 0 {
+	if err := unix.IoctlSetInt(0, unix.TIOCSCTTY, 0); err != nil {
 		return err
 	}
 	return nil