TinyX/dix/resource.c

/************************************************************

Copyright 1987, 1998  The Open Group

Permission to use, copy, modify, distribute, and sell this software and its
documentation for any purpose is hereby granted without fee, provided that
the above copyright notice appear in all copies and that both that
copyright notice and this permission notice appear in supporting
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The above copyright notice and this permission notice 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 THE
OPEN GROUP 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 The Open Group shall not be
used in advertising or otherwise to promote the sale, use or other dealings
in this Software without prior written authorization from The Open Group.

Copyright 1987 by Digital Equipment Corporation, Maynard, Massachusetts.

                        All Rights Reserved

Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted,
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in
supporting documentation, and that the name of Digital not be
used in advertising or publicity pertaining to distribution of the
software without specific, written prior permission.

DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
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********************************************************/
/* The panoramix components contained the following notice */
/*****************************************************************

Copyright (c) 1991, 1997 Digital Equipment Corporation, Maynard, Massachusetts.

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.

The above copyright notice and this permission notice 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
DIGITAL EQUIPMENT CORPORATION BE LIABLE FOR ANY CLAIM, DAMAGES, INCLUDING,
BUT NOT LIMITED TO CONSEQUENTIAL OR INCIDENTAL 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 Digital Equipment Corporation
shall not be used in advertising or otherwise to promote the sale, use or other
dealings in this Software without prior written authorization from Digital
Equipment Corporation.

******************************************************************/

/*	Routines to manage various kinds of resources:
 *
 *	CreateNewResourceType, InitClientResources,
 *	FakeClientID, AddResource, FreeResource, FreeClientResources,
 *	FreeAllResources, LookupIDByType, LookupIDByClass, GetXIDRange
 */

/*
 *      A resource ID is a 32 bit quantity, the upper 2 bits of which are
 *	off-limits for client-visible resources.  The next 8 bits are
 *      used as client ID, and the low 22 bits come from the client.
 *	A resource ID is "hashed" by extracting and xoring subfields
 *      (varying with the size of the hash table).
 *
 *      It is sometimes necessary for the server to create an ID that looks
 *      like it belongs to a client.  This ID, however,  must not be one
 *      the client actually can create, or we have the potential for conflict.
 *      The 31st bit of the ID is reserved for the server's use for this
 *      purpose.  By setting CLIENT_ID(id) to the client, the SERVER_BIT to
 *      1, and an otherwise arbitrary ID in the low 22 bits, we can create a
 *      resource "owned" by the client.
 */

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

#include <X11/X.h>
#include "misc.h"
#include "os.h"
#include "resource.h"
#include "dixstruct.h"
#include "opaque.h"
#include "windowstr.h"
#include "dixfont.h"
#include "colormap.h"
#include "inputstr.h"
#include "dixevents.h"
#include "dixgrabs.h"
#include "cursor.h"
#include <assert.h>

static void RebuildTable(int    /*client */
    );

#define SERVER_MINID 32

#define INITBUCKETS 64
#define INITHASHSIZE 6
#define MAXHASHSIZE 11

typedef struct _Resource {
    struct _Resource *next;
    XID id;
    RESTYPE type;
    pointer value;
} ResourceRec, *ResourcePtr;

#define NullResource ((ResourcePtr)NULL)

typedef struct _ClientResource {
    ResourcePtr *resources;
    int elements;
    int buckets;
    int hashsize;               /* log(2)(buckets) */
    XID fakeID;
    XID endFakeID;
    XID expectID;
} ClientResourceRec;

_X_EXPORT RESTYPE lastResourceType;

static RESTYPE lastResourceClass;

_X_EXPORT RESTYPE TypeMask;

static DeleteType *DeleteFuncs = (DeleteType *) NULL;

#ifdef XResExtension

_X_EXPORT Atom *ResourceNames = NULL;

_X_EXPORT void
RegisterResourceName(RESTYPE type, char *name)
{
    ResourceNames[type & TypeMask] = MakeAtom(name, strlen(name), TRUE);
}

#endif

_X_EXPORT RESTYPE
CreateNewResourceType(DeleteType deleteFunc)
{
    RESTYPE next = lastResourceType + 1;

    DeleteType *funcs;

    if (next & lastResourceClass)
        return 0;
    funcs = (DeleteType *) realloc(DeleteFuncs,
                                    (next + 1) * sizeof(DeleteType));
    if (!funcs)
        return 0;

#ifdef XResExtension
    {
        Atom *newnames;

        newnames = realloc(ResourceNames, (next + 1) * sizeof(Atom));
        if (!newnames)
            return 0;
        ResourceNames = newnames;
        ResourceNames[next] = 0;
    }
#endif

    lastResourceType = next;
    DeleteFuncs = funcs;
    DeleteFuncs[next] = deleteFunc;
    return next;
}

ClientResourceRec clientTable[MAXCLIENTS];

/*****************
 * InitClientResources
 *    When a new client is created, call this to allocate space
 *    in resource table
 *****************/

Bool
InitClientResources(ClientPtr client)
{
    int i, j;

    if (client == serverClient) {
        lastResourceType = RT_LASTPREDEF;
        lastResourceClass = RC_LASTPREDEF;
        TypeMask = RC_LASTPREDEF - 1;
        if (DeleteFuncs)
            free(DeleteFuncs);
        DeleteFuncs = malloc((lastResourceType + 1) *
                                            sizeof(DeleteType));
        if (!DeleteFuncs)
            return FALSE;
        DeleteFuncs[RT_NONE & TypeMask] = (DeleteType) NoopDDA;
        DeleteFuncs[RT_WINDOW & TypeMask] = DeleteWindow;
        DeleteFuncs[RT_PIXMAP & TypeMask] = dixDestroyPixmap;
        DeleteFuncs[RT_GC & TypeMask] = FreeGC;
        DeleteFuncs[RT_FONT & TypeMask] = CloseFont;
        DeleteFuncs[RT_CURSOR & TypeMask] = FreeCursor;
        DeleteFuncs[RT_COLORMAP & TypeMask] = FreeColormap;
        DeleteFuncs[RT_CMAPENTRY & TypeMask] = FreeClientPixels;
        DeleteFuncs[RT_OTHERCLIENT & TypeMask] = OtherClientGone;
        DeleteFuncs[RT_PASSIVEGRAB & TypeMask] = DeletePassiveGrab;

#ifdef XResExtension
        if (ResourceNames)
            free(ResourceNames);
        ResourceNames = malloc((lastResourceType + 1) * sizeof(Atom));
        if (!ResourceNames)
            return FALSE;
#endif
    }
    clientTable[i = client->index].resources =
        malloc(INITBUCKETS * sizeof(ResourcePtr));
    if (!clientTable[i].resources)
        return FALSE;
    clientTable[i].buckets = INITBUCKETS;
    clientTable[i].elements = 0;
    clientTable[i].hashsize = INITHASHSIZE;
    /* Many IDs allocated from the server client are visible to clients,
     * so we don't use the SERVER_BIT for them, but we have to start
     * past the magic value constants used in the protocol.  For normal
     * clients, we can start from zero, with SERVER_BIT set.
     */
    clientTable[i].fakeID = client->clientAsMask |
        (client->index ? SERVER_BIT : SERVER_MINID);
    clientTable[i].endFakeID = (clientTable[i].fakeID | RESOURCE_ID_MASK) + 1;
    clientTable[i].expectID = client->clientAsMask;
    for (j = 0; j < INITBUCKETS; j++) {
        clientTable[i].resources[j] = NullResource;
    }
    return TRUE;
}

static int
Hash(int client, register XID id)
{
    id &= RESOURCE_ID_MASK;
    switch (clientTable[client].hashsize) {
    case 6:
        return ((int) (0x03F & (id ^ (id >> 6) ^ (id >> 12))));
    case 7:
        return ((int) (0x07F & (id ^ (id >> 7) ^ (id >> 13))));
    case 8:
        return ((int) (0x0FF & (id ^ (id >> 8) ^ (id >> 16))));
    case 9:
        return ((int) (0x1FF & (id ^ (id >> 9))));
    case 10:
        return ((int) (0x3FF & (id ^ (id >> 10))));
    case 11:
        return ((int) (0x7FF & (id ^ (id >> 11))));
    }
    return -1;
}

static XID
AvailableID(register int client,
            register XID id, register XID maxid, register XID goodid)
{
    ResourcePtr res;

    if ((goodid >= id) && (goodid <= maxid))
        return goodid;
    for (; id <= maxid; id++) {
        res = clientTable[client].resources[Hash(client, id)];
        while (res && (res->id != id))
            res = res->next;
        if (!res)
            return id;
    }
    return 0;
}

_X_EXPORT void
GetXIDRange(int client, Bool server, XID *minp, XID *maxp)
{
    XID id, maxid;

    ResourcePtr *resp;

    ResourcePtr res;

    int i;

    XID goodid;

    id = (Mask) client << CLIENTOFFSET;
    if (server)
        id |= client ? SERVER_BIT : SERVER_MINID;
    maxid = id | RESOURCE_ID_MASK;
    goodid = 0;
    for (resp = clientTable[client].resources, i = clientTable[client].buckets;
         --i >= 0;) {
        for (res = *resp++; res; res = res->next) {
            if ((res->id < id) || (res->id > maxid))
                continue;
            if (((res->id - id) >= (maxid - res->id)) ?
                (goodid = AvailableID(client, id, res->id - 1, goodid)) :
                !(goodid = AvailableID(client, res->id + 1, maxid, goodid)))
                maxid = res->id - 1;
            else
                id = res->id + 1;
        }
    }
    if (id > maxid)
        id = maxid = 0;
    *minp = id;
    *maxp = maxid;
}

/**
 *  GetXIDList is called by the XC-MISC extension's MiscGetXIDList function.
 *  This function tries to find count unused XIDs for the given client.  It
 *  puts the IDs in the array pids and returns the number found, which should
 *  almost always be the number requested.
 *
 *  The circumstances that lead to a call to this function are very rare.
 *  Xlib must run out of IDs while trying to generate a request that wants
 *  multiple ID's, like the Multi-buffering CreateImageBuffers request.
 *
 *  No rocket science in the implementation; just iterate over all
 *  possible IDs for the given client and pick the first count IDs
 *  that aren't in use.  A more efficient algorithm could probably be
 *  invented, but this will be used so rarely that this should suffice.
 */

_X_EXPORT unsigned int
GetXIDList(ClientPtr pClient, unsigned count, XID *pids)
{
    unsigned int found = 0;

    XID id = pClient->clientAsMask;

    XID maxid;

    maxid = id | RESOURCE_ID_MASK;
    while ((found < count) && (id <= maxid)) {
        if (!LookupIDByClass(id, RC_ANY)) {
            pids[found++] = id;
        }
        id++;
    }
    return found;
}

/*
 * Return the next usable fake client ID.
 *
 * Normally this is just the next one in line, but if we've used the last
 * in the range, we need to find a new range of safe IDs to avoid
 * over-running another client.
 */

_X_EXPORT XID
FakeClientID(register int client)
{
    XID id, maxid;

    id = clientTable[client].fakeID++;
    if (id != clientTable[client].endFakeID)
        return id;
    GetXIDRange(client, TRUE, &id, &maxid);
    if (!id) {
        if (!client)
            FatalError("FakeClientID: server internal ids exhausted\n");
        MarkClientException(clients[client]);
        id = ((Mask) client << CLIENTOFFSET) | (SERVER_BIT * 3);
        maxid = id | RESOURCE_ID_MASK;
    }
    clientTable[client].fakeID = id + 1;
    clientTable[client].endFakeID = maxid + 1;
    return id;
}

_X_EXPORT Bool
AddResource(XID id, RESTYPE type, pointer value)
{
    int client;

    ClientResourceRec *rrec;

    ResourcePtr res, *head;

    client = CLIENT_ID(id);
    rrec = &clientTable[client];
    if (!rrec->buckets) {
        ErrorF("AddResource(%lx, %lx, %lx), client=%d \n",
               (unsigned long) id, type, (unsigned long) value, client);
        FatalError("client not in use\n");
    }
    if ((rrec->elements >= 4 * rrec->buckets) && (rrec->hashsize < MAXHASHSIZE))
        RebuildTable(client);
    head = &rrec->resources[Hash(client, id)];
    res = malloc(sizeof(ResourceRec));
    if (!res) {
        (*DeleteFuncs[type & TypeMask]) (value, id);
        return FALSE;
    }
    res->next = *head;
    res->id = id;
    res->type = type;
    res->value = value;
    *head = res;
    rrec->elements++;
    if (!(id & SERVER_BIT) && (id >= rrec->expectID))
        rrec->expectID = id + 1;
    return TRUE;
}

static void
RebuildTable(int client)
{
    int j;

    ResourcePtr res, next;

    ResourcePtr **tails, *resources;

    ResourcePtr **tptr, *rptr;

    /*
     * For now, preserve insertion order, since some ddx layers depend
     * on resources being free in the opposite order they are added.
     */

    j = 2 * clientTable[client].buckets;
    tails = (ResourcePtr **) ALLOCATE_LOCAL(j * sizeof(ResourcePtr *));
    if (!tails)
        return;
    resources = malloc(j * sizeof(ResourcePtr));
    if (!resources) {
        DEALLOCATE_LOCAL(tails);
        return;
    }
    for (rptr = resources, tptr = tails; --j >= 0; rptr++, tptr++) {
        *rptr = NullResource;
        *tptr = rptr;
    }
    clientTable[client].hashsize++;
    for (j = clientTable[client].buckets,
         rptr = clientTable[client].resources; --j >= 0; rptr++) {
        for (res = *rptr; res; res = next) {
            next = res->next;
            res->next = NullResource;
            tptr = &tails[Hash(client, res->id)];
            **tptr = res;
            *tptr = &res->next;
        }
    }
    DEALLOCATE_LOCAL(tails);
    clientTable[client].buckets *= 2;
    free(clientTable[client].resources);
    clientTable[client].resources = resources;
}

_X_EXPORT void
FreeResource(XID id, RESTYPE skipDeleteFuncType)
{
    int cid;

    ResourcePtr res;

    ResourcePtr *prev, *head;

    int *eltptr;

    int elements;

    Bool gotOne = FALSE;

    if (((cid = CLIENT_ID(id)) < MAXCLIENTS) && clientTable[cid].buckets) {
        head = &clientTable[cid].resources[Hash(cid, id)];
        eltptr = &clientTable[cid].elements;

        prev = head;
        while ((res = *prev)) {
            if (res->id == id) {
                RESTYPE rtype = res->type;

                *prev = res->next;
                elements = --*eltptr;
                if (rtype & RC_CACHED)
                    FlushClientCaches(res->id);
                if (rtype != skipDeleteFuncType)
                    (*DeleteFuncs[rtype & TypeMask]) (res->value, res->id);
                free(res);
                if (*eltptr != elements)
                    prev = head;        /* prev may no longer be valid */
                gotOne = TRUE;
            }
            else
                prev = &res->next;
        }
        if (clients[cid] && (id == clients[cid]->lastDrawableID)) {
            clients[cid]->lastDrawable = (DrawablePtr) WindowTable[0];
            clients[cid]->lastDrawableID = WindowTable[0]->drawable.id;
        }
    }
    if (!gotOne)
        ErrorF("Freeing resource id=%lX which isn't there.\n",
               (unsigned long) id);
}

_X_EXPORT void
FreeResourceByType(XID id, RESTYPE type, Bool skipFree)
{
    int cid;

    ResourcePtr res;

    ResourcePtr *prev, *head;

    if (((cid = CLIENT_ID(id)) < MAXCLIENTS) && clientTable[cid].buckets) {
        head = &clientTable[cid].resources[Hash(cid, id)];

        prev = head;
        while ((res = *prev)) {
            if (res->id == id && res->type == type) {
                *prev = res->next;
                if (type & RC_CACHED)
                    FlushClientCaches(res->id);
                if (!skipFree)
                    (*DeleteFuncs[type & TypeMask]) (res->value, res->id);
                free(res);
                break;
            }
            else
                prev = &res->next;
        }
        if (clients[cid] && (id == clients[cid]->lastDrawableID)) {
            clients[cid]->lastDrawable = (DrawablePtr) WindowTable[0];
            clients[cid]->lastDrawableID = WindowTable[0]->drawable.id;
        }
    }
}

/*
 * Change the value associated with a resource id.  Caller
 * is responsible for "doing the right thing" with the old
 * data
 */

_X_EXPORT Bool
ChangeResourceValue(XID id, RESTYPE rtype, pointer value)
{
    int cid;

    ResourcePtr res;

    if (((cid = CLIENT_ID(id)) < MAXCLIENTS) && clientTable[cid].buckets) {
        res = clientTable[cid].resources[Hash(cid, id)];

        for (; res; res = res->next)
            if ((res->id == id) && (res->type == rtype)) {
                if (rtype & RC_CACHED)
                    FlushClientCaches(res->id);
                res->value = value;
                return TRUE;
            }
    }
    return FALSE;
}

/* Note: if func adds or deletes resources, then func can get called
 * more than once for some resources.  If func adds new resources,
 * func might or might not get called for them.  func cannot both
 * add and delete an equal number of resources!
 */

_X_EXPORT void
FindClientResourcesByType(ClientPtr client,
                          RESTYPE type, FindResType func, pointer cdata)
{
    ResourcePtr *resources;

    ResourcePtr this, next;

    int i, elements;

    int *eltptr;

    if (!client)
        client = serverClient;

    resources = clientTable[client->index].resources;
    eltptr = &clientTable[client->index].elements;
    for (i = 0; i < clientTable[client->index].buckets; i++) {
        for (this = resources[i]; this; this = next) {
            next = this->next;
            if (!type || this->type == type) {
                elements = *eltptr;
                (*func) (this->value, this->id, cdata);
                if (*eltptr != elements)
                    next = resources[i];        /* start over */
            }
        }
    }
}

_X_EXPORT void
FindAllClientResources(ClientPtr client, FindAllRes func, pointer cdata)
{
    ResourcePtr *resources;

    ResourcePtr this, next;

    int i, elements;

    int *eltptr;

    if (!client)
        client = serverClient;

    resources = clientTable[client->index].resources;
    eltptr = &clientTable[client->index].elements;
    for (i = 0; i < clientTable[client->index].buckets; i++) {
        for (this = resources[i]; this; this = next) {
            next = this->next;
            elements = *eltptr;
            (*func) (this->value, this->id, this->type, cdata);
            if (*eltptr != elements)
                next = resources[i];    /* start over */
        }
    }
}

pointer
LookupClientResourceComplex(ClientPtr client,
                            RESTYPE type,
                            FindComplexResType func, pointer cdata)
{
    ResourcePtr *resources;

    ResourcePtr this;

    int i;

    if (!client)
        client = serverClient;

    resources = clientTable[client->index].resources;
    for (i = 0; i < clientTable[client->index].buckets; i++) {
        for (this = resources[i]; this; this = this->next) {
            if (!type || this->type == type) {
                if ((*func) (this->value, this->id, cdata))
                    return this->value;
            }
        }
    }
    return NULL;
}

void
FreeClientNeverRetainResources(ClientPtr client)
{
    ResourcePtr *resources;

    ResourcePtr this;

    ResourcePtr *prev;

    int j;

    if (!client)
        return;

    resources = clientTable[client->index].resources;
    for (j = 0; j < clientTable[client->index].buckets; j++) {
        prev = &resources[j];
        while ((this = *prev)) {
            RESTYPE rtype = this->type;

            if (rtype & RC_NEVERRETAIN) {
                *prev = this->next;
                if (rtype & RC_CACHED)
                    FlushClientCaches(this->id);
                (*DeleteFuncs[rtype & TypeMask]) (this->value, this->id);
                free(this);
            }
            else
                prev = &this->next;
        }
    }
}

void
FreeClientResources(ClientPtr client)
{
    ResourcePtr *resources;

    ResourcePtr this;

    int j;

    /* This routine shouldn't be called with a null client, but just in
       case ... */

    if (!client)
        return;

    HandleSaveSet(client);

    resources = clientTable[client->index].resources;
    for (j = 0; j < clientTable[client->index].buckets; j++) {
        /* It may seem silly to update the head of this resource list as
           we delete the members, since the entire list will be deleted any way,
           but there are some resource deletion functions "FreeClientPixels" for
           one which do a LookupID on another resource id (a Colormap id in this
           case), so the resource list must be kept valid up to the point that
           it is deleted, so every time we delete a resource, we must update the
           head, just like in FreeResource. I hope that this doesn't slow down
           mass deletion appreciably. PRH */

        ResourcePtr *head;

        head = &resources[j];

        for (this = *head; this; this = *head) {
            RESTYPE rtype = this->type;

            *head = this->next;
            if (rtype & RC_CACHED)
                FlushClientCaches(this->id);
            (*DeleteFuncs[rtype & TypeMask]) (this->value, this->id);
            free(this);
        }
    }
    free(clientTable[client->index].resources);
    clientTable[client->index].resources = NULL;
    clientTable[client->index].buckets = 0;
}

void
FreeAllResources()
{
    int i;

    for (i = currentMaxClients; --i >= 0;) {
        if (clientTable[i].buckets)
            FreeClientResources(clients[i]);
    }
}

_X_EXPORT Bool
LegalNewID(XID id, register ClientPtr client)
{

    return ((client->clientAsMask == (id & ~RESOURCE_ID_MASK)) &&
            ((clientTable[client->index].expectID <= id) ||
             !LookupIDByClass(id, RC_ANY)));
}

/* SecurityLookupIDByType and SecurityLookupIDByClass:
 * These are the heart of the resource ID security system.  They take
 * two additional arguments compared to the old LookupID functions:
 * the client doing the lookup, and the access mode (see resource.h).
 * The resource is returned if it exists and the client is allowed access,
 * else NULL is returned.
 */

_X_EXPORT pointer
SecurityLookupIDByType(ClientPtr client, XID id, RESTYPE rtype, Mask mode)
{
    int cid;

    ResourcePtr res;

    pointer retval = NULL;

    if (((cid = CLIENT_ID(id)) < MAXCLIENTS) && clientTable[cid].buckets) {
        res = clientTable[cid].resources[Hash(cid, id)];

        for (; res; res = res->next)
            if ((res->id == id) && (res->type == rtype)) {
                retval = res->value;
                break;
            }
    }
    return retval;
}

_X_EXPORT pointer
SecurityLookupIDByClass(ClientPtr client, XID id, RESTYPE classes, Mask mode)
{
    int cid;

    ResourcePtr res = NULL;

    pointer retval = NULL;

    if (((cid = CLIENT_ID(id)) < MAXCLIENTS) && clientTable[cid].buckets) {
        res = clientTable[cid].resources[Hash(cid, id)];

        for (; res; res = res->next)
            if ((res->id == id) && (res->type & classes)) {
                retval = res->value;
                break;
            }
    }
    return retval;
}

/* We can't replace the LookupIDByType and LookupIDByClass functions with
 * macros because of compatibility with loadable servers.
 */

_X_EXPORT pointer
LookupIDByType(XID id, RESTYPE rtype)
{
    return SecurityLookupIDByType(NullClient, id, rtype, SecurityUnknownAccess);
}

_X_EXPORT pointer
LookupIDByClass(XID id, RESTYPE classes)
{
    return SecurityLookupIDByClass(NullClient, id, classes,
                                   SecurityUnknownAccess);
}