forked from Cloud-Foundations/Dominator
/
pty.go
54 lines (48 loc) · 1.09 KB
/
pty.go
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// +build linux
package main
import (
"os"
"strconv"
"syscall"
"unsafe"
"github.com/Cloud-Foundations/Dominator/lib/wsyscall"
)
func openPty() (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 := unlockpt(p); err != nil {
return nil, nil, err
}
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) {
var n uint32
err := wsyscall.Ioctl(int(f.Fd()), syscall.TIOCGPTN,
uintptr(unsafe.Pointer(&n)))
if err != nil {
return "", err
}
return "/dev/pts/" + strconv.Itoa(int(n)), nil
}
func unlockpt(f *os.File) error {
var u int32
// Use TIOCSPTLCK with a zero valued arg to clear the slave pty lock.
return wsyscall.Ioctl(int(f.Fd()), syscall.TIOCSPTLCK,
uintptr(unsafe.Pointer(&u)))
}