67 lines
1.4 KiB
Go
67 lines
1.4 KiB
Go
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package pty
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import (
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"errors"
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"os"
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"syscall"
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"unsafe"
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)
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func open() (pty, tty *os.File, err error) {
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p, err := os.OpenFile("/dev/ptmx", os.O_RDWR, 0)
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if err != nil {
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return nil, nil, err
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}
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// In case of error after this point, make sure we close the ptmx fd.
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defer func() {
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if err != nil {
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_ = p.Close() // Best effort.
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}
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}()
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sname, err := ptsname(p)
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if err != nil {
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return nil, nil, err
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}
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if err := grantpt(p); err != nil {
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return nil, nil, err
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}
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// In NetBSD unlockpt() does nothing, so it isn't called here.
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t, err := os.OpenFile(sname, os.O_RDWR|syscall.O_NOCTTY, 0)
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if err != nil {
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return nil, nil, err
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}
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return p, t, nil
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}
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func ptsname(f *os.File) (string, error) {
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/*
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* from ptsname(3): The ptsname() function is equivalent to:
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* struct ptmget pm;
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* ioctl(fd, TIOCPTSNAME, &pm) == -1 ? NULL : pm.sn;
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*/
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var ptm ptmget
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if err := ioctl(f.Fd(), uintptr(ioctl_TIOCPTSNAME), uintptr(unsafe.Pointer(&ptm))); err != nil {
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return "", err
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}
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name := make([]byte, len(ptm.Sn))
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for i, c := range ptm.Sn {
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name[i] = byte(c)
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if c == 0 {
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return string(name[:i]), nil
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}
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}
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return "", errors.New("TIOCPTSNAME string not NUL-terminated")
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}
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func grantpt(f *os.File) error {
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/*
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* from grantpt(3): Calling grantpt() is equivalent to:
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* ioctl(fd, TIOCGRANTPT, 0);
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*/
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return ioctl(f.Fd(), uintptr(ioctl_TIOCGRANTPT), 0)
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}
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