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