gotty/vendor/github.com/creack/pty/pty_freebsd.go
2020-02-28 08:42:08 +02:00

79 lines
1.5 KiB
Go

package pty
import (
"errors"
"os"
"syscall"
"unsafe"
)
func posixOpenpt(oflag int) (fd int, err error) {
r0, _, e1 := syscall.Syscall(syscall.SYS_POSIX_OPENPT, uintptr(oflag), 0, 0)
fd = int(r0)
if e1 != 0 {
err = e1
}
return fd, err
}
func open() (pty, tty *os.File, err error) {
fd, err := posixOpenpt(syscall.O_RDWR | syscall.O_CLOEXEC)
if err != nil {
return nil, nil, err
}
p := os.NewFile(uintptr(fd), "/dev/pts")
// In case of error after this point, make sure we close the pts fd.
defer func() {
if err != nil {
_ = p.Close() // Best effort.
}
}()
sname, err := ptsname(p)
if err != nil {
return nil, nil, err
}
t, err := os.OpenFile("/dev/"+sname, os.O_RDWR, 0)
if err != nil {
return nil, nil, err
}
return p, t, nil
}
func isptmaster(fd uintptr) (bool, error) {
err := ioctl(fd, syscall.TIOCPTMASTER, 0)
return err == nil, err
}
var (
emptyFiodgnameArg fiodgnameArg
ioctlFIODGNAME = _IOW('f', 120, unsafe.Sizeof(emptyFiodgnameArg))
)
func ptsname(f *os.File) (string, error) {
master, err := isptmaster(f.Fd())
if err != nil {
return "", err
}
if !master {
return "", syscall.EINVAL
}
const n = _C_SPECNAMELEN + 1
var (
buf = make([]byte, n)
arg = fiodgnameArg{Len: n, Buf: (*byte)(unsafe.Pointer(&buf[0]))}
)
if err := ioctl(f.Fd(), ioctlFIODGNAME, uintptr(unsafe.Pointer(&arg))); err != nil {
return "", err
}
for i, c := range buf {
if c == 0 {
return string(buf[:i]), nil
}
}
return "", errors.New("FIODGNAME string not NUL-terminated")
}