Use unix.IoctlSetTermios instead of ioctl system call on darwin

This is necessary due to an upgrade in Golang's sys package, which no longer allows for direct system calls on darwin.

Signed-off-by: Priya Wadhwa <priyawadhwa@google.com>

Author: Priya Wadhwa

go.mod

@@ -5,5 +5,5 @@ go 1.14
 require (
 	github.com/mitchellh/go-ps v1.0.0
 	github.com/stretchr/testify v1.6.1
-	golang.org/x/sys v0.0.0-20200722175500-76b94024e4b6
+	golang.org/x/sys v0.0.0-20201015000850-e3ed0017c211
 )

go.sum

@@ -9,6 +9,8 @@ github.com/stretchr/testify v1.6.1 h1:hDPOHmpOpP40lSULcqw7IrRb/u7w6RpDC9399XyoNd
 github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 golang.org/x/sys v0.0.0-20200722175500-76b94024e4b6 h1:X9xIZ1YU8bLZA3l6gqDUHSFiD0GFI9S548h6C8nDtOY=
 golang.org/x/sys v0.0.0-20200722175500-76b94024e4b6/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20201015000850-e3ed0017c211 h1:9UQO31fZ+0aKQOFldThf7BKPMJTiBfWycGh/u3UoO88=
+golang.org/x/sys v0.0.0-20201015000850-e3ed0017c211/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

go/pty_util_darwin.go

@@ -7,26 +7,23 @@ which is under Apache License Version 2.0, January 2004
 */
 import (
 	"os"
-	"unsafe"
 
 	"golang.org/x/sys/unix"
 )
 
 func tcget(fd uintptr, p *unix.Termios) error {
-	return ioctl(fd, unix.TIOCGETA, uintptr(unsafe.Pointer(p)))
-}
-
-func tcset(fd uintptr, p *unix.Termios) error {
-	return ioctl(fd, unix.TIOCSETA, uintptr(unsafe.Pointer(p)))
-}
-
-func ioctl(fd, flag, data uintptr) error {
-	if _, _, err := unix.Syscall(unix.SYS_IOCTL, fd, flag, data); err != 0 {
+	termios, err := unix.IoctlGetTermios(int(fd), unix.TIOCGETA)
+	if err != nil {
 		return err
 	}
+	*p = *termios
 	return nil
 }
 
+func tcset(fd uintptr, p *unix.Termios) error {
+	return unix.IoctlSetTermios(int(fd), unix.TIOCSETA, p)
+}
+
 func saneTerminal(f *os.File) error {
 	// Go doesn't have a wrapper for any of the termios ioctls.
 	var termios unix.Termios