glxcmds.c

/*
 * SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008)
 * Copyright (C) 1991-2000 Silicon Graphics, Inc. All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice including the dates of first publication and
 * either this permission notice or a reference to
 * http://oss.sgi.com/projects/FreeB/
 * shall be included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * SILICON GRAPHICS, INC. BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF
 * OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 * Except as contained in this notice, the name of Silicon Graphics, Inc.
 * shall not be used in advertising or otherwise to promote the sale, use or
 * other dealings in this Software without prior written authorization from
 * Silicon Graphics, Inc.
 */

#ifdef HAVE_DIX_CONFIG_H
#include <dix-config.h>
#endif

#include <string.h>
#include <assert.h>

#include "glxserver.h"
#include <GL/glxtokens.h>
#include <X11/extensions/presenttokens.h>
#include <unpack.h>
#include <pixmapstr.h>
#include <windowstr.h>
#include "glxutil.h"
#include "glxext.h"
#include "indirect_dispatch.h"
#include "indirect_table.h"
#include "indirect_util.h"
#include "protocol-versions.h"
#include "glxvndabi.h"

static char GLXServerVendorName[] = "SGI";

_X_HIDDEN int
validGlxScreen(ClientPtr client, int screen, __GLXscreen ** pGlxScreen,
               int *err)
{
    /*
     ** Check if screen exists.
     */
    if (screen < 0 || screen >= screenInfo.numScreens) {
        client->errorValue = screen;
        *err = BadValue;
        return FALSE;
    }
    *pGlxScreen = glxGetScreen(screenInfo.screens[screen]);

    return TRUE;
}

_X_HIDDEN int
validGlxFBConfig(ClientPtr client, __GLXscreen * pGlxScreen, XID id,
                 __GLXconfig ** config, int *err)
{
    __GLXconfig *m;

    for (m = pGlxScreen->fbconfigs; m != NULL; m = m->next)
        if (m->fbconfigID == id) {
            *config = m;
            return TRUE;
        }

    client->errorValue = id;
    *err = __glXError(GLXBadFBConfig);

    return FALSE;
}

static int
validGlxVisual(ClientPtr client, __GLXscreen * pGlxScreen, XID id,
               __GLXconfig ** config, int *err)
{
    int i;

    for (i = 0; i < pGlxScreen->numVisuals; i++)
        if (pGlxScreen->visuals[i]->visualID == id) {
            *config = pGlxScreen->visuals[i];
            return TRUE;
        }

    client->errorValue = id;
    *err = BadValue;

    return FALSE;
}

static int
validGlxFBConfigForWindow(ClientPtr client, __GLXconfig * config,
                          DrawablePtr pDraw, int *err)
{
    ScreenPtr pScreen = pDraw->pScreen;
    VisualPtr pVisual = NULL;
    XID vid;
    int i;

    vid = wVisual((WindowPtr) pDraw);
    for (i = 0; i < pScreen->numVisuals; i++) {
        if (pScreen->visuals[i].vid == vid) {
            pVisual = &pScreen->visuals[i];
            break;
        }
    }

    /* FIXME: What exactly should we check here... */
    if (pVisual->class != glxConvertToXVisualType(config->visualType) ||
        !(config->drawableType & GLX_WINDOW_BIT)) {
        client->errorValue = pDraw->id;
        *err = BadMatch;
        return FALSE;
    }

    return TRUE;
}

_X_HIDDEN int
validGlxContext(ClientPtr client, XID id, int access_mode,
                __GLXcontext ** context, int *err)
{
    /* no ghost contexts */
    if (id & SERVER_BIT) {
        *err = __glXError(GLXBadContext);
        return FALSE;
    }

    *err = dixLookupResourceByType((void **) context, id,
                                   __glXContextRes, client, access_mode);
    if (*err != Success || (*context)->idExists == GL_FALSE) {
        client->errorValue = id;
        if (*err == BadValue || *err == Success)
            *err = __glXError(GLXBadContext);
        return FALSE;
    }

    return TRUE;
}

int
validGlxDrawable(ClientPtr client, XID id, int type, int access_mode,
                 __GLXdrawable ** drawable, int *err)
{
    int rc;

    rc = dixLookupResourceByType((void **) drawable, id,
                                 __glXDrawableRes, client, access_mode);
    if (rc != Success && rc != BadValue) {
        *err = rc;
        client->errorValue = id;
        return FALSE;
    }

    /* If the ID of the glx drawable we looked up doesn't match the id
     * we looked for, it's because we looked it up under the X
     * drawable ID (see DoCreateGLXDrawable). */
    if (rc == BadValue ||
        (*drawable)->drawId != id ||
        (type != GLX_DRAWABLE_ANY && type != (*drawable)->type)) {
        client->errorValue = id;
        switch (type) {
        case GLX_DRAWABLE_WINDOW:
            *err = __glXError(GLXBadWindow);
            return FALSE;
        case GLX_DRAWABLE_PIXMAP:
            *err = __glXError(GLXBadPixmap);
            return FALSE;
        case GLX_DRAWABLE_PBUFFER:
            *err = __glXError(GLXBadPbuffer);
            return FALSE;
        case GLX_DRAWABLE_ANY:
            *err = __glXError(GLXBadDrawable);
            return FALSE;
        }
    }

    return TRUE;
}

void
__glXContextDestroy(__GLXcontext * context)
{
    lastGLContext = NULL;
}

static void
__glXdirectContextDestroy(__GLXcontext * context)
{
    __glXContextDestroy(context);
    free(context);
}

static int
__glXdirectContextLoseCurrent(__GLXcontext * context)
{
    return GL_TRUE;
}

_X_HIDDEN __GLXcontext *
__glXdirectContextCreate(__GLXscreen * screen,
                         __GLXconfig * modes, __GLXcontext * shareContext)
{
    __GLXcontext *context;

    context = calloc(1, sizeof(__GLXcontext));
    if (context == NULL)
        return NULL;

    context->config = modes;
    context->destroy = __glXdirectContextDestroy;
    context->loseCurrent = __glXdirectContextLoseCurrent;

    return context;
}

/**
 * Create a GL context with the given properties.  This routine is used
 * to implement \c glXCreateContext, \c glXCreateNewContext, and
 * \c glXCreateContextWithConfigSGIX.  This works because of the hack way
 * that GLXFBConfigs are implemented.  Basically, the FBConfigID is the
 * same as the VisualID.
 */

static int
DoCreateContext(__GLXclientState * cl, GLXContextID gcId,
                GLXContextID shareList, __GLXconfig * config,
                __GLXscreen * pGlxScreen, GLboolean isDirect)
{
    ClientPtr client = cl->client;
    __GLXcontext *glxc, *shareglxc;
    int err;

    /*
     ** Find the display list space that we want to share.
     **
     ** NOTE: In a multithreaded X server, we would need to keep a reference
     ** count for each display list so that if one client detroyed a list that
     ** another client was using, the list would not really be freed until it
     ** was no longer in use.  Since this sample implementation has no support
     ** for multithreaded servers, we don't do this.
     */
    if (shareList == None) {
        shareglxc = 0;
    }
    else {
        if (!validGlxContext(client, shareList, DixReadAccess,
                             &shareglxc, &err))
            return err;

        /* Page 26 (page 32 of the PDF) of the GLX 1.4 spec says:
         *
         *     "The server context state for all sharing contexts must exist
         *     in a single address space or a BadMatch error is generated."
         *
         * If the share context is indirect, force the new context to also be
         * indirect.  If the shard context is direct but the new context
         * cannot be direct, generate BadMatch.
         */
        if (shareglxc->isDirect && !isDirect) {
            client->errorValue = shareList;
            return BadMatch;
        }
        else if (!shareglxc->isDirect) {
            /*
             ** Create an indirect context regardless of what the client asked
             ** for; this way we can share display list space with shareList.
             */
            isDirect = GL_FALSE;
        }

        /* Core GLX doesn't explicitly require this, but GLX_ARB_create_context
         * does (see glx/createcontext.c), and it's assumed by our
         * implementation anyway, so let's be consistent about it.
         */
        if (shareglxc->pGlxScreen != pGlxScreen) {
            client->errorValue = shareglxc->pGlxScreen->pScreen->myNum;
            return BadMatch;
        }
    }

    /*
     ** Allocate memory for the new context
     */
    if (!isDirect) {
        /* Only allow creating indirect GLX contexts if allowed by
         * server command line.  Indirect GLX is of limited use (since
         * it's only GL 1.4), it's slower than direct contexts, and
         * it's a massive attack surface for buffer overflow type
         * errors.
         */
        if (!enableIndirectGLX) {
            client->errorValue = isDirect;
            return BadValue;
        }

        /* Without any attributes, the only error that the driver should be
         * able to generate is BadAlloc.  As result, just drop the error
         * returned from the driver on the floor.
         */
        glxc = pGlxScreen->createContext(pGlxScreen, config, shareglxc,
                                         0, NULL, &err);
    }
    else
        glxc = __glXdirectContextCreate(pGlxScreen, config, shareglxc);
    if (!glxc) {
        return BadAlloc;
    }

    /* Initialize the GLXcontext structure.
     */
    glxc->pGlxScreen = pGlxScreen;
    glxc->config = config;
    glxc->id = gcId;
    glxc->share_id = shareList;
    glxc->idExists = GL_TRUE;
    glxc->isDirect = isDirect;
    glxc->renderMode = GL_RENDER;

    /* The GLX_ARB_create_context_robustness spec says:
     *
     *     "The default value for GLX_CONTEXT_RESET_NOTIFICATION_STRATEGY_ARB
     *     is GLX_NO_RESET_NOTIFICATION_ARB."
     *
     * Without using glXCreateContextAttribsARB, there is no way to specify a
     * non-default reset notification strategy.
     */
    glxc->resetNotificationStrategy = GLX_NO_RESET_NOTIFICATION_ARB;

#ifdef GLX_CONTEXT_RELEASE_BEHAVIOR_ARB
    /* The GLX_ARB_context_flush_control spec says:
     *
     *     "The default value [for GLX_CONTEXT_RELEASE_BEHAVIOR] is
     *     CONTEXT_RELEASE_BEHAVIOR_FLUSH, and may in some cases be changed
     *     using platform-specific context creation extensions."
     *
     * Without using glXCreateContextAttribsARB, there is no way to specify a
     * non-default release behavior.
     */
    glxc->releaseBehavior = GLX_CONTEXT_RELEASE_BEHAVIOR_FLUSH_ARB;
#endif

    /* Add the new context to the various global tables of GLX contexts.
     */
    if (!__glXAddContext(glxc)) {
        (*glxc->destroy) (glxc);
        client->errorValue = gcId;
        return BadAlloc;
    }

    return Success;
}

int
__glXDisp_CreateContext(__GLXclientState * cl, GLbyte * pc)
{
    xGLXCreateContextReq *req = (xGLXCreateContextReq *) pc;
    __GLXconfig *config;
    __GLXscreen *pGlxScreen;
    int err;

    if (!validGlxScreen(cl->client, req->screen, &pGlxScreen, &err))
        return err;
    if (!validGlxVisual(cl->client, pGlxScreen, req->visual, &config, &err))
        return err;

    return DoCreateContext(cl, req->context, req->shareList,
                           config, pGlxScreen, req->isDirect);
}

int
__glXDisp_CreateNewContext(__GLXclientState * cl, GLbyte * pc)
{
    xGLXCreateNewContextReq *req = (xGLXCreateNewContextReq *) pc;
    __GLXconfig *config;
    __GLXscreen *pGlxScreen;
    int err;

    if (!validGlxScreen(cl->client, req->screen, &pGlxScreen, &err))
        return err;
    if (!validGlxFBConfig(cl->client, pGlxScreen, req->fbconfig, &config, &err))
        return err;

    return DoCreateContext(cl, req->context, req->shareList,
                           config, pGlxScreen, req->isDirect);
}

int
__glXDisp_CreateContextWithConfigSGIX(__GLXclientState * cl, GLbyte * pc)
{
    ClientPtr client = cl->client;
    xGLXCreateContextWithConfigSGIXReq *req =
        (xGLXCreateContextWithConfigSGIXReq *) pc;
    __GLXconfig *config;
    __GLXscreen *pGlxScreen;
    int err;

    REQUEST_SIZE_MATCH(xGLXCreateContextWithConfigSGIXReq);

    if (!validGlxScreen(cl->client, req->screen, &pGlxScreen, &err))
        return err;
    if (!validGlxFBConfig(cl->client, pGlxScreen, req->fbconfig, &config, &err))
        return err;

    return DoCreateContext(cl, req->context, req->shareList,
                           config, pGlxScreen, req->isDirect);
}

int
__glXDisp_DestroyContext(__GLXclientState * cl, GLbyte * pc)
{
    xGLXDestroyContextReq *req = (xGLXDestroyContextReq *) pc;
    __GLXcontext *glxc;
    int err;

    if (!validGlxContext(cl->client, req->context, DixDestroyAccess,
                         &glxc, &err))
        return err;

    glxc->idExists = GL_FALSE;
    if (glxc->currentClient) {
        XID ghost = FakeClientID(glxc->currentClient->index);

        if (!AddResource(ghost, __glXContextRes, glxc))
            return BadAlloc;
        ChangeResourceValue(glxc->id, __glXContextRes, NULL);
        glxc->id = ghost;
    }

    FreeResourceByType(req->context, __glXContextRes, FALSE);

    return Success;
}

__GLXcontext *
__glXLookupContextByTag(__GLXclientState * cl, GLXContextTag tag)
{
    return glxServer.getContextTagPrivate(cl->client, tag);
}

static __GLXconfig *
inferConfigForWindow(__GLXscreen *pGlxScreen, WindowPtr pWin)
{
    int i, vid = wVisual(pWin);

    for (i = 0; i < pGlxScreen->numVisuals; i++)
        if (pGlxScreen->visuals[i]->visualID == vid)
            return pGlxScreen->visuals[i];

    return NULL;
}

/**
 * This is a helper function to handle the legacy (pre GLX 1.3) cases
 * where passing an X window to glXMakeCurrent is valid.  Given a
 * resource ID, look up the GLX drawable if available, otherwise, make
 * sure it's an X window and create a GLX drawable one the fly.
 */
static __GLXdrawable *
__glXGetDrawable(__GLXcontext * glxc, GLXDrawable drawId, ClientPtr client,
                 int *error)
{
    DrawablePtr pDraw;
    __GLXdrawable *pGlxDraw;
    __GLXconfig *config;
    __GLXscreen *pGlxScreen;
    int rc;

    if (validGlxDrawable(client, drawId, GLX_DRAWABLE_ANY,
                         DixWriteAccess, &pGlxDraw, &rc)) {
        if (glxc != NULL &&
            glxc->config != NULL &&
            glxc->config != pGlxDraw->config) {
            client->errorValue = drawId;
            *error = BadMatch;
            return NULL;
        }

        return pGlxDraw;
    }

    /* No active context and an unknown drawable, bail. */
    if (glxc == NULL) {
        client->errorValue = drawId;
        *error = BadMatch;
        return NULL;
    }

    /* The drawId wasn't a GLX drawable.  Make sure it's a window and
     * create a GLXWindow for it.  Check that the drawable screen
     * matches the context screen and that the context fbconfig is
     * compatible with the window visual. */

    rc = dixLookupDrawable(&pDraw, drawId, client, 0, DixGetAttrAccess);
    if (rc != Success || pDraw->type != DRAWABLE_WINDOW) {
        client->errorValue = drawId;
        *error = __glXError(GLXBadDrawable);
        return NULL;
    }

    pGlxScreen = glxc->pGlxScreen;
    if (pDraw->pScreen != pGlxScreen->pScreen) {
        client->errorValue = pDraw->pScreen->myNum;
        *error = BadMatch;
        return NULL;
    }

    config = glxc->config;
    if (!config)
        config = inferConfigForWindow(pGlxScreen, (WindowPtr)pDraw);
    if (!config) {
        /*
         * If we get here, we've tried to bind a no-config context to a
         * window without a corresponding fbconfig, presumably because
         * we don't support GL on it (PseudoColor perhaps). From GLX Section
         * 3.3.7 "Rendering Contexts":
         *
         * "If draw or read are not compatible with ctx a BadMatch error
         * is generated."
         */
        *error = BadMatch;
        return NULL;
    }

    if (!validGlxFBConfigForWindow(client, config, pDraw, error))
        return NULL;

    pGlxDraw = pGlxScreen->createDrawable(client, pGlxScreen, pDraw, drawId,
                                          GLX_DRAWABLE_WINDOW, drawId, config);
    if (!pGlxDraw) {
	*error = BadAlloc;
	return NULL;
    }

    /* since we are creating the drawablePrivate, drawId should be new */
    if (!AddResource(drawId, __glXDrawableRes, pGlxDraw)) {
        *error = BadAlloc;
        return NULL;
    }

    return pGlxDraw;
}

/*****************************************************************************/
/*
** Make an OpenGL context and drawable current.
*/

int
xorgGlxMakeCurrent(ClientPtr client, GLXContextTag tag, XID drawId, XID readId,
                   XID contextId, GLXContextTag newContextTag)
{
    __GLXclientState *cl = glxGetClient(client);
    __GLXcontext *glxc = NULL, *prevglxc = NULL;
    __GLXdrawable *drawPriv = NULL;
    __GLXdrawable *readPriv = NULL;
    int error;

    /* Drawables but no context makes no sense */
    if (!contextId && (drawId || readId))
        return BadMatch;

    /* If either drawable is null, the other must be too */
    if ((drawId == None) != (readId == None))
        return BadMatch;

    /* Look up old context. If we have one, it must be in a usable state. */
    if (tag != 0) {
        prevglxc = glxServer.getContextTagPrivate(client, tag);

        if (prevglxc && prevglxc->renderMode != GL_RENDER) {
            /* Oops.  Not in render mode render. */
            client->errorValue = prevglxc->id;
            return __glXError(GLXBadContextState);
        }
    }

    /* Look up new context. It must not be current for someone else. */
    if (contextId != None) {
        int status;

        if (!validGlxContext(client, contextId, DixUseAccess, &glxc, &error))
            return error;

        if ((glxc != prevglxc) && glxc->currentClient)
            return BadAccess;

        if (drawId) {
            drawPriv = __glXGetDrawable(glxc, drawId, client, &status);
            if (drawPriv == NULL)
                return status;
        }

        if (readId) {
            readPriv = __glXGetDrawable(glxc, readId, client, &status);
            if (readPriv == NULL)
                return status;
        }
    }

    if (prevglxc) {
        /* Flush the previous context if needed. */
        Bool need_flush = !prevglxc->isDirect;
#ifdef GLX_CONTEXT_RELEASE_BEHAVIOR_ARB
        if (prevglxc->releaseBehavior == GLX_CONTEXT_RELEASE_BEHAVIOR_NONE_ARB)
            need_flush = GL_FALSE;
#endif
        if (need_flush) {
            if (!__glXForceCurrent(cl, tag, (int *) &error))
                return error;
            glFlush();
        }

        /* Make the previous context not current. */
        if (!(*prevglxc->loseCurrent) (prevglxc))
            return __glXError(GLXBadContext);

        lastGLContext = NULL;
        if (!prevglxc->isDirect) {
            prevglxc->drawPriv = NULL;
            prevglxc->readPriv = NULL;
        }
    }

    if (glxc && !glxc->isDirect) {
        glxc->drawPriv = drawPriv;
        glxc->readPriv = readPriv;

        /* make the context current */
        lastGLContext = glxc;
        if (!(*glxc->makeCurrent) (glxc)) {
            lastGLContext = NULL;
            glxc->drawPriv = NULL;
            glxc->readPriv = NULL;
            return __glXError(GLXBadContext);
        }

        glxc->currentClient = client;
        glxServer.setContextTagPrivate(client, newContextTag, glxc);
    }

    if (prevglxc) {
        prevglxc->currentClient = NULL;
        if (!prevglxc->idExists) {
            FreeResourceByType(prevglxc->id, __glXContextRes, FALSE);
        }
    }

    return Success;
}

int
__glXDisp_MakeCurrent(__GLXclientState * cl, GLbyte * pc)
{
    return BadImplementation;
}

int
__glXDisp_MakeContextCurrent(__GLXclientState * cl, GLbyte * pc)
{
    return BadImplementation;
}

int
__glXDisp_MakeCurrentReadSGI(__GLXclientState * cl, GLbyte * pc)
{
    return BadImplementation;
}

int
__glXDisp_IsDirect(__GLXclientState * cl, GLbyte * pc)
{
    ClientPtr client = cl->client;
    xGLXIsDirectReq *req = (xGLXIsDirectReq *) pc;
    xGLXIsDirectReply reply;
    __GLXcontext *glxc;
    int err;

    if (!validGlxContext(cl->client, req->context, DixReadAccess, &glxc, &err))
        return err;

    reply = (xGLXIsDirectReply) {
        .type = X_Reply,
        .sequenceNumber = client->sequence,
        .length = 0,
        .isDirect = glxc->isDirect
    };

    if (client->swapped) {
        __GLX_DECLARE_SWAP_VARIABLES;
        __GLX_SWAP_SHORT(&reply.sequenceNumber);
        __GLX_SWAP_INT(&reply.length);
    }
    WriteToClient(client, sz_xGLXIsDirectReply, &reply);

    return Success;
}

int
__glXDisp_QueryVersion(__GLXclientState * cl, GLbyte * pc)
{
    ClientPtr client = cl->client;
    xGLXQueryVersionReq *req = (xGLXQueryVersionReq *) pc;
    xGLXQueryVersionReply reply;
    GLuint major, minor;

    REQUEST_SIZE_MATCH(xGLXQueryVersionReq);

    major = req->majorVersion;
    minor = req->minorVersion;
    (void) major;
    (void) minor;

    /*
     ** Server should take into consideration the version numbers sent by the
     ** client if it wants to work with older clients; however, in this
     ** implementation the server just returns its version number.
     */
    reply = (xGLXQueryVersionReply) {
        .type = X_Reply,
        .sequenceNumber = client->sequence,
        .length = 0,
        .majorVersion = SERVER_GLX_MAJOR_VERSION,
        .minorVersion = SERVER_GLX_MINOR_VERSION
    };

    if (client->swapped) {
        __GLX_DECLARE_SWAP_VARIABLES;
        __GLX_SWAP_SHORT(&reply.sequenceNumber);
        __GLX_SWAP_INT(&reply.length);
        __GLX_SWAP_INT(&reply.majorVersion);
        __GLX_SWAP_INT(&reply.minorVersion);
    }

    WriteToClient(client, sz_xGLXQueryVersionReply, &reply);
    return Success;
}

int
__glXDisp_WaitGL(__GLXclientState * cl, GLbyte * pc)
{
    xGLXWaitGLReq *req = (xGLXWaitGLReq *) pc;
    GLXContextTag tag;
    __GLXcontext *glxc = NULL;
    int error;

    tag = req->contextTag;
    if (tag) {
        glxc = __glXLookupContextByTag(cl, tag);
        if (!glxc)
            return __glXError(GLXBadContextTag);

        if (!__glXForceCurrent(cl, req->contextTag, &error))
            return error;

        glFinish();
    }

    if (glxc && glxc->drawPriv && glxc->drawPriv->waitGL)
        (*glxc->drawPriv->waitGL) (glxc->drawPriv);

    return Success;
}

int
__glXDisp_WaitX(__GLXclientState * cl, GLbyte * pc)
{
    xGLXWaitXReq *req = (xGLXWaitXReq *) pc;
    GLXContextTag tag;
    __GLXcontext *glxc = NULL;
    int error;

    tag = req->contextTag;
    if (tag) {
        glxc = __glXLookupContextByTag(cl, tag);
        if (!glxc)
            return __glXError(GLXBadContextTag);

        if (!__glXForceCurrent(cl, req->contextTag, &error))
            return error;
    }

    if (glxc && glxc->drawPriv && glxc->drawPriv->waitX)
        (*glxc->drawPriv->waitX) (glxc->drawPriv);

    return Success;
}

int
__glXDisp_CopyContext(__GLXclientState * cl, GLbyte * pc)
{
    ClientPtr client = cl->client;
    xGLXCopyContextReq *req = (xGLXCopyContextReq *) pc;
    GLXContextID source;
    GLXContextID dest;
    GLXContextTag tag;
    unsigned long mask;
    __GLXcontext *src, *dst;
    int error;

    source = req->source;
    dest = req->dest;
    tag = req->contextTag;
    mask = req->mask;
    if (!validGlxContext(cl->client, source, DixReadAccess, &src, &error))
        return error;
    if (!validGlxContext(cl->client, dest, DixWriteAccess, &dst, &error))
        return error;

    /*
     ** They must be in the same address space, and same screen.
     ** NOTE: no support for direct rendering contexts here.
     */
    if (src->isDirect || dst->isDirect || (src->pGlxScreen != dst->pGlxScreen)) {
        client->errorValue = source;
        return BadMatch;
    }

    /*
     ** The destination context must not be current for any client.
     */
    if (dst->currentClient) {
        client->errorValue = dest;
        return BadAccess;
    }

    if (tag) {
        __GLXcontext *tagcx = __glXLookupContextByTag(cl, tag);

        if (!tagcx) {
            return __glXError(GLXBadContextTag);
        }
        if (tagcx != src) {
            /*
             ** This would be caused by a faulty implementation of the client
             ** library.
             */
            return BadMatch;
        }
        /*
         ** In this case, glXCopyContext is in both GL and X streams, in terms
         ** of sequentiality.
         */
        if (__glXForceCurrent(cl, tag, &error)) {
            /*
             ** Do whatever is needed to make sure that all preceding requests
             ** in both streams are completed before the copy is executed.
             */
            glFinish();
        }
        else {
            return error;
        }
    }
    /*
     ** Issue copy.  The only reason for failure is a bad mask.
     */
    if (!(*dst->copy) (dst, src, mask)) {
        client->errorValue = mask;
        return BadValue;
    }
    return Success;
}

enum {
    GLX_VIS_CONFIG_UNPAIRED = 18,
    GLX_VIS_CONFIG_PAIRED = 22
};

enum {
    GLX_VIS_CONFIG_TOTAL = GLX_VIS_CONFIG_UNPAIRED + GLX_VIS_CONFIG_PAIRED
};

int
__glXDisp_GetVisualConfigs(__GLXclientState * cl, GLbyte * pc)
{
    xGLXGetVisualConfigsReq *req = (xGLXGetVisualConfigsReq *) pc;
    ClientPtr client = cl->client;
    xGLXGetVisualConfigsReply reply;
    __GLXscreen *pGlxScreen;
    __GLXconfig *modes;
    CARD32 buf[GLX_VIS_CONFIG_TOTAL];
    int p, i, err;

    __GLX_DECLARE_SWAP_VARIABLES;
    __GLX_DECLARE_SWAP_ARRAY_VARIABLES;

    if (!validGlxScreen(cl->client, req->screen, &pGlxScreen, &err))
        return err;

    reply = (xGLXGetVisualConfigsReply) {
        .type = X_Reply,
        .sequenceNumber = client->sequence,
        .length = (pGlxScreen->numVisuals *
                   __GLX_SIZE_CARD32 * GLX_VIS_CONFIG_TOTAL) >> 2,
        .numVisuals = pGlxScreen->numVisuals,
        .numProps = GLX_VIS_CONFIG_TOTAL
    };

    if (client->swapped) {
        __GLX_SWAP_SHORT(&reply.sequenceNumber);
        __GLX_SWAP_INT(&reply.length);