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78 lines
1.5 KiB
78 lines
1.5 KiB
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 posixOpenpt(oflag int) (fd int, err error) { |
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r0, _, e1 := syscall.Syscall(syscall.SYS_POSIX_OPENPT, uintptr(oflag), 0, 0) |
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fd = int(r0) |
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if e1 != 0 { |
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err = e1 |
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} |
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return fd, err |
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} |
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func open() (pty, tty *os.File, err error) { |
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fd, err := posixOpenpt(syscall.O_RDWR | syscall.O_CLOEXEC) |
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if err != nil { |
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return nil, nil, err |
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} |
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p := os.NewFile(uintptr(fd), "/dev/pts") |
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// In case of error after this point, make sure we close the pts 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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t, err := os.OpenFile("/dev/"+sname, 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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return p, t, nil |
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} |
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func isptmaster(fd uintptr) (bool, error) { |
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err := ioctl(fd, syscall.TIOCPTMASTER, 0) |
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return err == nil, err |
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} |
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var ( |
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emptyFiodgnameArg fiodgnameArg |
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ioctlFIODGNAME = _IOW('f', 120, unsafe.Sizeof(emptyFiodgnameArg)) |
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) |
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func ptsname(f *os.File) (string, error) { |
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master, err := isptmaster(f.Fd()) |
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if err != nil { |
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return "", err |
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} |
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if !master { |
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return "", syscall.EINVAL |
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} |
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const n = _C_SPECNAMELEN + 1 |
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var ( |
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buf = make([]byte, n) |
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arg = fiodgnameArg{Len: n, Buf: (*byte)(unsafe.Pointer(&buf[0]))} |
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) |
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if err := ioctl(f.Fd(), ioctlFIODGNAME, uintptr(unsafe.Pointer(&arg))); err != nil { |
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return "", err |
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} |
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for i, c := range buf { |
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if c == 0 { |
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return string(buf[:i]), nil |
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} |
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} |
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return "", errors.New("FIODGNAME string not NUL-terminated") |
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}
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