exp/draw/x11: support X11 vendors other than "The X.Org Foundation".

R=adg, ehog.hedge
CC=golang-dev
https://golang.org/cl/2385041

diff --git a/src/pkg/exp/draw/x11/conn.go b/src/pkg/exp/draw/x11/conn.go
index 70c2ee2d8348d7cd19adb40051bc5288555be189..fdf6281b4168ad1c7b1df2de112225f564d13738 100644 (file)
--- a/src/pkg/exp/draw/x11/conn.go
+++ b/src/pkg/exp/draw/x11/conn.go
@@ -489,16 +489,13 @@ func (c *conn) handshake() os.Error {
        if err != nil {
                return err
        }
-       // Read the vendor length.
+       // Read the vendor length and round it up to a multiple of 4,
+       // for X11 protocol alignment reasons.
        vendorLen, err := readU16LE(c.r, c.buf[0:2])
        if err != nil {
                return err
        }
-       if vendorLen != 20 {
-               // For now, assume the vendor is "The X.Org Foundation". Supporting different
-               // vendors would require figuring out how much padding we need to read.
-               return os.NewError("unsupported X vendor")
-       }
+       vendorLen = (vendorLen + 3) &^ 3
        // Read the maximum request length.
        maxReqLen, err := readU16LE(c.r, c.buf[0:2])
        if err != nil {
@@ -517,10 +514,13 @@ func (c *conn) handshake() os.Error {
        if err != nil {
                return err
        }
-       // Ignore some things that we don't care about (totalling 30 bytes):
+       // Ignore some things that we don't care about (totalling 10 + vendorLen bytes):
        // imageByteOrder(1), bitmapFormatBitOrder(1), bitmapFormatScanlineUnit(1) bitmapFormatScanlinePad(1),
-       // minKeycode(1), maxKeycode(1), padding(4), vendor(20, hard-coded above).
-       _, err = io.ReadFull(c.r, c.buf[0:30])
+       // minKeycode(1), maxKeycode(1), padding(4), vendor (vendorLen).
+       if 10+int(vendorLen) > cap(c.buf) {
+               return os.NewError("unsupported X vendor")
+       }
+       _, err = io.ReadFull(c.r, c.buf[0:10+int(vendorLen)])
        if err != nil {
                return err
        }