DockerCLI/vendor/github.com/creack/pty/pty_linux.go

55 lines
1.2 KiB
Go

//go:build linux
// +build linux
package pty
import (
"os"
"strconv"
"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 := unlockpt(p); err != nil {
return nil, nil, err
}
t, err := os.OpenFile(sname, os.O_RDWR|syscall.O_NOCTTY, 0) //nolint:gosec // Expected Open from a variable.
if err != nil {
return nil, nil, err
}
return p, t, nil
}
func ptsname(f *os.File) (string, error) {
var n _C_uint
err := ioctl(f, syscall.TIOCGPTN, uintptr(unsafe.Pointer(&n))) //nolint:gosec // Expected unsafe pointer for Syscall call.
if err != nil {
return "", err
}
return "/dev/pts/" + strconv.Itoa(int(n)), nil
}
func unlockpt(f *os.File) error {
var u _C_int
// use TIOCSPTLCK with a pointer to zero to clear the lock.
return ioctl(f, syscall.TIOCSPTLCK, uintptr(unsafe.Pointer(&u))) //nolint:gosec // Expected unsafe pointer for Syscall call.
}