| package pty |
| |
| import ( |
| "errors" |
| "os" |
| "syscall" |
| "unsafe" |
| ) |
| |
| 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 |
| } |
| // In case of error after this point, make sure we close the ptmx fd. |
| defer func() { |
| if err != nil { |
| _ = p.Close() // Best effort. |
| } |
| }() |
| |
| sname, err := ptsname(p) |
| if err != nil { |
| return nil, nil, err |
| } |
| |
| if err := grantpt(p); err != nil { |
| return nil, nil, err |
| } |
| |
| // In NetBSD unlockpt() does nothing, so it isn't called here. |
| |
| t, err := os.OpenFile(sname, os.O_RDWR|syscall.O_NOCTTY, 0) |
| if err != nil { |
| return nil, nil, err |
| } |
| return p, t, nil |
| } |
| |
| func ptsname(f *os.File) (string, error) { |
| /* |
| * from ptsname(3): The ptsname() function is equivalent to: |
| * struct ptmget pm; |
| * ioctl(fd, TIOCPTSNAME, &pm) == -1 ? NULL : pm.sn; |
| */ |
| var ptm ptmget |
| if err := ioctl(f.Fd(), uintptr(ioctl_TIOCPTSNAME), uintptr(unsafe.Pointer(&ptm))); err != nil { |
| return "", err |
| } |
| name := make([]byte, len(ptm.Sn)) |
| for i, c := range ptm.Sn { |
| name[i] = byte(c) |
| if c == 0 { |
| return string(name[:i]), nil |
| } |
| } |
| return "", errors.New("TIOCPTSNAME string not NUL-terminated") |
| } |
| |
| func grantpt(f *os.File) error { |
| /* |
| * from grantpt(3): Calling grantpt() is equivalent to: |
| * ioctl(fd, TIOCGRANTPT, 0); |
| */ |
| return ioctl(f.Fd(), uintptr(ioctl_TIOCGRANTPT), 0) |
| } |