[PATCH 8/8] Xephyr: Use _XEatDataWords (from Xlib 1.6) instead of _XEatData

[Alan Coopersmith]

Simplifies code and reduces risk of overflow from converting length
field in X replies from words to bytes.

One call to _XEatData is left in ephyrHostGLXGetStringFromServer where
it's already been checked for overflow, and other values have been
subtracted from it to reduce the size of data remaining to be eaten.

Signed-off-by: Alan Coopersmith <alan.coopersmith at oracle.com>
---
 configure.ac                     |    2 +-
 hw/kdrive/ephyr/XF86dri.c        |    8 ++++----
 hw/kdrive/ephyr/ephyrhostglx.c   |    4 +++-
 hw/kdrive/ephyr/ephyrhostvideo.c |    2 +-
 4 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/configure.ac b/configure.ac
index 206b9c4..75281f0 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2112,7 +2112,7 @@ if test "$KDRIVE" = yes; then
        AC_DEFINE(KDRIVE_MOUSE, 1, [Enable KDrive mouse driver])
     fi
 
-    XEPHYR_REQUIRED_LIBS="x11 $LIBXEXT xau xdmcp"
+    XEPHYR_REQUIRED_LIBS="x11 >= 1.6 $LIBXEXT xau xdmcp"
     if test "x$XV" = xyes; then
         XEPHYR_REQUIRED_LIBS="$XEPHYR_REQUIRED_LIBS xv"
     fi
diff --git a/hw/kdrive/ephyr/XF86dri.c b/hw/kdrive/ephyr/XF86dri.c
index 9f230fc..15b6219 100644
--- a/hw/kdrive/ephyr/XF86dri.c
+++ b/hw/kdrive/ephyr/XF86dri.c
@@ -231,7 +231,7 @@ XF86DRIOpenConnection(Display * dpy, int screen,
         else
             *busIdString = NULL;
         if (*busIdString == NULL) {
-            _XEatData(dpy, ((rep.busIdStringLength + 3) & ~3));
+            _XEatDataWords(dpy, rep.length);
             UnlockDisplay(dpy);
             SyncHandle();
             TRACE("OpenConnection... return False");
@@ -333,7 +333,7 @@ XF86DRIGetClientDriverName(Display * dpy, int screen,
         else
             *clientDriverName = NULL;
         if (*clientDriverName == NULL) {
-            _XEatData(dpy, ((rep.clientDriverNameLength + 3) & ~3));
+            _XEatDataWords(dpy, rep.length);
             UnlockDisplay(dpy);
             SyncHandle();
             TRACE("GetClientDriverName... return False");
@@ -539,7 +539,7 @@ XF86DRIGetDrawableInfo(Display * dpy, int screen, Drawable drawable,
                           SIZEOF(xGenericReply) +
                           total_rects * sizeof(drm_clip_rect_t)) +
                          3) & ~3) >> 2)) {
-        _XEatData(dpy, rep.length);
+        _XEatDataWords(dpy, rep.length);
         UnlockDisplay(dpy);
         SyncHandle();
         TRACE("GetDrawableInfo... return False");
@@ -613,7 +613,7 @@ XF86DRIGetDeviceInfo(Display * dpy, int screen, drm_handle_t * hFrameBuffer,
 
     if (rep.length) {
         if (!(*pDevPrivate = (void *) calloc(rep.devPrivateSize, 1))) {
-            _XEatData(dpy, ((rep.devPrivateSize + 3) & ~3));
+            _XEatDataWords(dpy, rep.length);
             UnlockDisplay(dpy);
             SyncHandle();
             TRACE("GetDeviceInfo... return False");
diff --git a/hw/kdrive/ephyr/ephyrhostglx.c b/hw/kdrive/ephyr/ephyrhostglx.c
index 90f450c..6a4392f 100644
--- a/hw/kdrive/ephyr/ephyrhostglx.c
+++ b/hw/kdrive/ephyr/ephyrhostglx.c
@@ -211,8 +211,10 @@ ephyrHostGLXGetStringFromServer(int a_screen_number,
     _XReply(dpy, (xReply *) &reply, 0, False);
 
 #if UINT32_MAX >= (ULONG_MAX / 4)
-    if (reply.length >= (ULONG_MAX / 4))
+    if (reply.length >= (ULONG_MAX / 4)) {
+        _XEatDataWords(dpy, reply.length);
         goto eat_out;
+    }
 #endif
     if (reply.length > 0) {
         length = (unsigned long) reply.length * 4;
diff --git a/hw/kdrive/ephyr/ephyrhostvideo.c b/hw/kdrive/ephyr/ephyrhostvideo.c
index 362aa05..05e9ad9 100644
--- a/hw/kdrive/ephyr/ephyrhostvideo.c
+++ b/hw/kdrive/ephyr/ephyrhostvideo.c
@@ -677,7 +677,7 @@ ephyrHostXVQueryImageAttributes(int a_port_id,
         _XRead(dpy, (char *) a_offsets, rep.num_planes << 2);
     }
     else {
-        _XEatData(dpy, rep.length << 2);
+        _XEatDataWords(dpy, rep.length);
     }
     *a_width = rep.width;
     *a_height = rep.height;
-- 
1.7.9.2