From ab9b4e1f593b2006a61c0f5440c2d7d3af80ea74 Mon Sep 17 00:00:00 2001
From: Ian Romanick <ian.d.romanick@intel.com>
Date: Tue, 20 Jan 2009 13:55:18 -0800
Subject: [PATCH] Fix issues with glXMakeContextCurrent and
 glXMakeCurrentReadSGI

There were several bugs in the infrastructure for these two routines.

1. GLX_ALIAS was incorrectly used.  The function and its alias must be
identical!  glXMakeContextCurrent / glXMakeCurrentReadSGI and
MakeContextCurrent had different parameters.  This caused the last
parameter of MakeContextCurrent to get random values.

2. We based the implementation of glXMakeContextCurrent on the manual
page instead of the GLX spec.  The GLX spec says that
glXMakeContextCurrent can be passed a Window as a drawable.  When this
happens, it will behave just like glXMakeCurrentReadSGI or
glXMakeCurrent.

3. If there was a problem finding or creating the DRI drawable,
MakeContextCurrent would crash instead of returning an error.

This commit fixes all three issues, and fixes bug #18367 and bug #19625.
---
 src/glx/x11/glxcurrent.c | 46 ++++++++++++++++++++++------------------
 1 file changed, 25 insertions(+), 21 deletions(-)

diff --git a/src/glx/x11/glxcurrent.c b/src/glx/x11/glxcurrent.c
index 5af46cf0ba7..4d0a7c65eba 100644
--- a/src/glx/x11/glxcurrent.c
+++ b/src/glx/x11/glxcurrent.c
@@ -312,13 +312,11 @@ SendMakeCurrentRequest(Display * dpy, CARD8 opcode,
 
 #ifdef GLX_DIRECT_RENDERING
 static __GLXDRIdrawable *
-FetchDRIDrawable(Display * dpy,
-                 GLXDrawable glxDrawable, GLXContext gc, Bool pre13)
+FetchDRIDrawable(Display * dpy, GLXDrawable glxDrawable, GLXContext gc)
 {
    __GLXdisplayPrivate *const priv = __glXInitialize(dpy);
    __GLXDRIdrawable *pdraw;
    __GLXscreenConfigs *psc;
-   XID drawable;
 
    if (priv == NULL)
       return NULL;
@@ -330,15 +328,7 @@ FetchDRIDrawable(Display * dpy,
    if (__glxHashLookup(psc->drawHash, glxDrawable, (void *) &pdraw) == 0)
       return pdraw;
 
-   /* If this is glXMakeCurrent (pre GLX 1.3) we allow creating the
-    * GLX drawable on the fly.  Otherwise we pass None as the X
-    * drawable */
-   if (pre13)
-      drawable = glxDrawable;
-   else
-      drawable = None;
-
-   pdraw = psc->driScreen->createDrawable(psc, drawable,
+   pdraw = psc->driScreen->createDrawable(psc, glxDrawable,
                                           glxDrawable, gc->mode);
    if (__glxHashInsert(psc->drawHash, glxDrawable, pdraw)) {
       (*pdraw->destroyDrawable) (pdraw);
@@ -357,7 +347,7 @@ FetchDRIDrawable(Display * dpy,
  */
 static Bool
 MakeContextCurrent(Display * dpy, GLXDrawable draw,
-                   GLXDrawable read, GLXContext gc, Bool pre13)
+                   GLXDrawable read, GLXContext gc)
 {
    xGLXMakeCurrentReply reply;
    const GLXContext oldGC = __glXGetCurrentContext();
@@ -384,8 +374,21 @@ MakeContextCurrent(Display * dpy, GLXDrawable draw,
 #ifdef GLX_DIRECT_RENDERING
    /* Bind the direct rendering context to the drawable */
    if (gc && gc->driContext) {
-      __GLXDRIdrawable *pdraw = FetchDRIDrawable(dpy, draw, gc, pre13);
-      __GLXDRIdrawable *pread = FetchDRIDrawable(dpy, read, gc, pre13);
+      __GLXDRIdrawable *pdraw = FetchDRIDrawable(dpy, draw, gc);
+      __GLXDRIdrawable *pread = FetchDRIDrawable(dpy, read, gc);
+
+      if ((pdraw == NULL) || (pread == NULL)) {
+         xError error;
+
+         error.errorCode = GLXBadDrawable;
+         error.resourceID = (pdraw == NULL) ? draw : read;
+         error.sequenceNumber = dpy->request;
+         error.type = X_Error;
+         error.majorCode = gc->majorOpcode;
+         error.minorCode = X_GLXMakeContextCurrent;
+         _XError(dpy, &error);
+         return False;
+      }
 
       bindReturnValue =
          (gc->driContext->bindContext) (gc->driContext, pdraw, pread);
@@ -516,15 +519,16 @@ MakeContextCurrent(Display * dpy, GLXDrawable draw,
 PUBLIC Bool
 glXMakeCurrent(Display * dpy, GLXDrawable draw, GLXContext gc)
 {
-   return MakeContextCurrent(dpy, draw, draw, gc, True);
+   return MakeContextCurrent(dpy, draw, draw, gc);
 }
 
 PUBLIC
 GLX_ALIAS(Bool, glXMakeCurrentReadSGI,
           (Display * dpy, GLXDrawable d, GLXDrawable r, GLXContext ctx),
-          (dpy, d, r, ctx, False), MakeContextCurrent)
+          (dpy, d, r, ctx), MakeContextCurrent)
 
-     PUBLIC GLX_ALIAS(Bool, glXMakeContextCurrent,
-                      (Display * dpy, GLXDrawable d, GLXDrawable r,
-                       GLXContext ctx), (dpy, d, r, ctx, False),
-                      MakeContextCurrent)
+PUBLIC
+GLX_ALIAS(Bool, glXMakeContextCurrent,
+	  (Display * dpy, GLXDrawable d, GLXDrawable r,
+	   GLXContext ctx), (dpy, d, r, ctx),
+	  MakeContextCurrent)
-- 
2.30.2