package console

import (
	"fmt"
	"os"
	"unsafe"

	"golang.org/x/sys/unix"
)

const (
	cmdTcGet = unix.TCGETS
	cmdTcSet = unix.TCSETS
)

func ioctl(fd, flag, data uintptr) error {
	if _, _, err := unix.Syscall(unix.SYS_IOCTL, fd, flag, data); err != 0 {
		return err
	}
	return nil
}

// unlockpt unlocks the slave pseudoterminal device corresponding to the master pseudoterminal referred to by f.
// unlockpt should be called before opening the slave side of a pty.
func unlockpt(f *os.File) error {
	var u int32
	return ioctl(f.Fd(), unix.TIOCSPTLCK, uintptr(unsafe.Pointer(&u)))
}

// ptsname retrieves the name of the first available pts for the given master.
func ptsname(f *os.File) (string, error) {
	n, err := unix.IoctlGetInt(int(f.Fd()), unix.TIOCGPTN)
	if err != nil {
		return "", err
	}
	return fmt.Sprintf("/dev/pts/%d", n), nil
}

package console

import (
	"fmt"
	"os"
	"unsafe"

	"golang.org/x/sys/unix"
)

const (
	cmdTcGet = unix.TCGETS
	cmdTcSet = unix.TCSETS
)

// unlockpt unlocks the slave pseudoterminal device corresponding to the master pseudoterminal referred to by f.
// unlockpt should be called before opening the slave side of a pty.
func unlockpt(f *os.File) error {
	var u int32
	if _, _, err := unix.Syscall(unix.SYS_IOCTL, f.Fd(), unix.TIOCSPTLCK, uintptr(unsafe.Pointer(&u))); err != 0 {
		return err
	}
	return nil
}

// ptsname retrieves the name of the first available pts for the given master.
func ptsname(f *os.File) (string, error) {
	var u uint32
	if _, _, err := unix.Syscall(unix.SYS_IOCTL, f.Fd(), unix.TIOCGPTN, uintptr(unsafe.Pointer(&u))); err != 0 {
		return "", err
	}
	return fmt.Sprintf("/dev/pts/%d", u), nil
}

Fix ptsname() for big-endian architectures
Fix ptsname() for big-endian architectures

On big-endian architectures unix.IoctlGetInt() leads to a wrong result
because a 32 bit value is stored into a 64 bit buffer. When dereferencing
the result is left shifted by 32. Without this patch ptsname() returns
a wrong path from the second pty onwards.
To protect syscalls against re-arranging by the GC the conversion from
unsafe.Pointer to uintptr must occur in the Syscall expression itself.
See the documentation of the unsafe package for details.

Signed-off-by: Peter Morjan <964d0cf54dbf76d367f54f543a3db8d083ad8566@de.ibm.com>
