term_linux.go RawHistoryFolder

1//go:build linux
2
3package rawterm
4
5import (
6	"fmt"
7	"os"
8	"syscall"
9	"unsafe"
10)
11
12const (
13	reqGetTermios = syscall.TCGETS
14	reqSetTermios = syscall.TCSETS
15)
16
17// PtsNumber returns the pty slave number for the master referenced by
18// masterFD (TIOCGPTN).
19func PtsNumber(masterFD int) (int, error) {
20	var n int32
21	if err := ioctl(masterFD, syscall.TIOCGPTN, unsafe.Pointer(&n)); err != nil {
22		return 0, fmt.Errorf("rawterm: get pts number: %w", err)
23	}
24	return int(n), nil
25}
26
27// UnlockPt unlocks the pty slave associated with masterFD so it can be opened
28// (TIOCSPTLCK).
29func UnlockPt(masterFD int) error {
30	var unlock int32
31	if err := ioctl(masterFD, syscall.TIOCSPTLCK, unsafe.Pointer(&unlock)); err != nil {
32		return fmt.Errorf("rawterm: unlock pty: %w", err)
33	}
34	return nil
35}
36
37// PreparePty unlocks the slave associated with masterFD and opens it.
38func PreparePty(masterFD int) (*os.File, error) {
39	n, err := PtsNumber(masterFD)
40	if err != nil {
41		return nil, err
42	}
43	if err := UnlockPt(masterFD); err != nil {
44		return nil, err
45	}
46	slaveName := fmt.Sprintf("/dev/pts/%d", n)
47	slave, err := os.OpenFile(slaveName, os.O_RDWR|syscall.O_NOCTTY, 0)
48	if err != nil {
49		return nil, fmt.Errorf("rawterm: open %s: %w", slaveName, err)
50	}
51	return slave, nil
52}