111 lines
2.3 KiB
Go
111 lines
2.3 KiB
Go
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package xgb
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/*
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auth.go contains functions to facilitate the parsing of .Xauthority files.
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It is largely unmodified from the original XGB package that I forked.
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*/
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import (
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"encoding/binary"
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"errors"
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"io"
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"os"
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)
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// readAuthority reads the X authority file for the DISPLAY.
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// If hostname == "" or hostname == "localhost",
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// then use the system's hostname (as returned by os.Hostname) instead.
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func readAuthority(hostname, display string) (
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name string, data []byte, err error) {
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// b is a scratch buffer to use and should be at least 256 bytes long
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// (i.e. it should be able to hold a hostname).
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b := make([]byte, 256)
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// As per /usr/include/X11/Xauth.h.
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const familyLocal = 256
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const familyWild = 65535
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if len(hostname) == 0 || hostname == "localhost" {
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hostname, err = os.Hostname()
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if err != nil {
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return "", nil, err
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}
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}
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fname := os.Getenv("XAUTHORITY")
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if len(fname) == 0 {
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home := os.Getenv("HOME")
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if len(home) == 0 {
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err = errors.New("Xauthority not found: $XAUTHORITY, $HOME not set")
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return "", nil, err
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}
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fname = home + "/.Xauthority"
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}
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r, err := os.Open(fname)
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if err != nil {
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return "", nil, err
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}
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defer r.Close()
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for {
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var family uint16
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if err := binary.Read(r, binary.BigEndian, &family); err != nil {
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return "", nil, err
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}
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addr, err := getString(r, b)
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if err != nil {
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return "", nil, err
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}
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disp, err := getString(r, b)
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if err != nil {
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return "", nil, err
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}
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name0, err := getString(r, b)
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if err != nil {
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return "", nil, err
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}
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data0, err := getBytes(r, b)
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if err != nil {
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return "", nil, err
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}
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addrmatch := (family == familyWild) ||
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(family == familyLocal && addr == hostname)
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dispmatch := (disp == "") || (disp == display)
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if addrmatch && dispmatch {
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return name0, data0, nil
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}
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}
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panic("unreachable")
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}
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func getBytes(r io.Reader, b []byte) ([]byte, error) {
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var n uint16
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if err := binary.Read(r, binary.BigEndian, &n); err != nil {
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return nil, err
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} else if n > uint16(len(b)) {
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return nil, errors.New("bytes too long for buffer")
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}
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if _, err := io.ReadFull(r, b[0:n]); err != nil {
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return nil, err
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}
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return b[0:n], nil
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}
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func getString(r io.Reader, b []byte) (string, error) {
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b, err := getBytes(r, b)
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if err != nil {
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return "", err
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}
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return string(b), nil
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}
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