| package pty |
| |
| import ( |
| "errors" |
| "os" |
| "syscall" |
| "unsafe" |
| ) |
| |
| // see ioccom.h |
| const sys_IOCPARM_MASK = 0x1fff |
| |
| func open() (pty, tty *os.File, err error) { |
| p, err := os.OpenFile("/dev/ptmx", os.O_RDWR, 0) |
| if err != nil { |
| return nil, nil, err |
| } |
| |
| sname, err := ptsname(p) |
| if err != nil { |
| return nil, nil, err |
| } |
| |
| err = grantpt(p) |
| if err != nil { |
| return nil, nil, err |
| } |
| |
| err = unlockpt(p) |
| if err != nil { |
| return nil, nil, err |
| } |
| |
| t, err := os.OpenFile(sname, os.O_RDWR, 0) |
| if err != nil { |
| return nil, nil, err |
| } |
| return p, t, nil |
| } |
| |
| func ptsname(f *os.File) (string, error) { |
| var n [(syscall.TIOCPTYGNAME >> 16) & sys_IOCPARM_MASK]byte |
| |
| ioctl(f.Fd(), syscall.TIOCPTYGNAME, uintptr(unsafe.Pointer(&n))) |
| for i, c := range n { |
| if c == 0 { |
| return string(n[:i]), nil |
| } |
| } |
| return "", errors.New("TIOCPTYGNAME string not NUL-terminated") |
| } |
| |
| func grantpt(f *os.File) error { |
| var u int |
| return ioctl(f.Fd(), syscall.TIOCPTYGRANT, uintptr(unsafe.Pointer(&u))) |
| } |
| |
| func unlockpt(f *os.File) error { |
| var u int |
| return ioctl(f.Fd(), syscall.TIOCPTYUNLK, uintptr(unsafe.Pointer(&u))) |
| } |
| |
| func ioctl(fd, cmd, ptr uintptr) error { |
| _, _, e := syscall.Syscall(syscall.SYS_IOCTL, fd, cmd, ptr) |
| if e != 0 { |
| return syscall.ENOTTY |
| } |
| return nil |
| } |