github.com/dolfly/pty@v1.2.1/pty_dragonfly.go (about)

     1  //go:build dragonfly
     2  //+build dragonfly
     3  
     4  package pty
     5  
     6  import (
     7  	"errors"
     8  	"os"
     9  	"strings"
    10  	"syscall"
    11  	"unsafe"
    12  )
    13  
    14  // same code as pty_darwin.go
    15  func open() (pty, tty *os.File, err error) {
    16  	p, err := os.OpenFile("/dev/ptmx", os.O_RDWR, 0)
    17  	if err != nil {
    18  		return nil, nil, err
    19  	}
    20  	// In case of error after this point, make sure we close the ptmx fd.
    21  	defer func() {
    22  		if err != nil {
    23  			_ = p.Close() // Best effort.
    24  		}
    25  	}()
    26  
    27  	sname, err := ptsname(p)
    28  	if err != nil {
    29  		return nil, nil, err
    30  	}
    31  
    32  	if err := grantpt(p); err != nil {
    33  		return nil, nil, err
    34  	}
    35  
    36  	if err := unlockpt(p); err != nil {
    37  		return nil, nil, err
    38  	}
    39  
    40  	t, err := os.OpenFile(sname, os.O_RDWR, 0)
    41  	if err != nil {
    42  		return nil, nil, err
    43  	}
    44  	return p, t, nil
    45  }
    46  
    47  func grantpt(f *os.File) error {
    48  	_, err := isptmaster(f.Fd())
    49  	return err
    50  }
    51  
    52  func unlockpt(f *os.File) error {
    53  	_, err := isptmaster(f.Fd())
    54  	return err
    55  }
    56  
    57  func isptmaster(fd uintptr) (bool, error) {
    58  	err := ioctl(fd, syscall.TIOCISPTMASTER, 0)
    59  	return err == nil, err
    60  }
    61  
    62  var (
    63  	emptyFiodgnameArg fiodgnameArg
    64  	ioctl_FIODNAME    = _IOW('f', 120, unsafe.Sizeof(emptyFiodgnameArg))
    65  )
    66  
    67  func ptsname(f *os.File) (string, error) {
    68  	name := make([]byte, _C_SPECNAMELEN)
    69  	fa := fiodgnameArg{Name: (*byte)(unsafe.Pointer(&name[0])), Len: _C_SPECNAMELEN, Pad_cgo_0: [4]byte{0, 0, 0, 0}}
    70  
    71  	err := ioctl(f.Fd(), ioctl_FIODNAME, uintptr(unsafe.Pointer(&fa)))
    72  	if err != nil {
    73  		return "", err
    74  	}
    75  
    76  	for i, c := range name {
    77  		if c == 0 {
    78  			s := "/dev/" + string(name[:i])
    79  			return strings.Replace(s, "ptm", "pts", -1), nil
    80  		}
    81  	}
    82  	return "", errors.New("TIOCPTYGNAME string not NUL-terminated")
    83  }