xfixes: canonicalize reply structures

Canonicalize all reply structs onto stack allocation and static
initialization, like already done in most other extension. So make
the code easier to understand and allow further simplifications by
subsequent commits (we can then use generic macros for doing the
actual sending, as well as byteorder swapping, size computation, etc),
Also gaining a little bit efficiency by skipping some heap allocations.

Dynamically sized payload buffers (where the upper bound isn't known),
are still allocated on heap.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>

xfixes/cursor.c

@@ -355,7 +355,6 @@ ProcXFixesGetCursorImage(ClientPtr client)
 {
 /*    REQUEST(xXFixesGetCursorImageReq); */
     CursorPtr pCursor;
-    CARD32 *image;
     int npixels, width, height, rc, x, y;
 
     REQUEST_SIZE_MATCH(xXFixesGetCursorImageReq);
@@ -371,39 +370,40 @@ ProcXFixesGetCursorImage(ClientPtr client)
     height = pCursor->bits->height;
     npixels = width * height;
 
-    xXFixesGetCursorImageReply *rep = calloc(1,
+    CARD32 *image = calloc(npixels, sizeof(CARD32));
-                 sizeof(xXFixesGetCursorImageReply) + npixels * sizeof(CARD32));
+    if (!image)
-    if (!rep)
         return BadAlloc;
 
-    rep->type = X_Reply;
-    rep->sequenceNumber = client->sequence;
-    rep->length = npixels;
-    rep->width = width;
-    rep->height = height;
-    rep->x = x;
-    rep->y = y;
-    rep->xhot = pCursor->bits->xhot;
-    rep->yhot = pCursor->bits->yhot;
-    rep->cursorSerial = pCursor->serialNumber;
-
-    image = (CARD32 *) (rep + 1);
     CopyCursorToImage(pCursor, image);
+
+    xXFixesGetCursorImageReply rep = {
+        .type = X_Reply,
+        .sequenceNumber = client->sequence,
+        .length = npixels,
+        .width = width,
+        .height = height,
+        .x = x,
+        .y = y,
+        .xhot = pCursor->bits->xhot,
+        .yhot = pCursor->bits->yhot,
+        .cursorSerial = pCursor->serialNumber,
+    };
+
     if (client->swapped) {
-        swaps(&rep->sequenceNumber);
+        swaps(&rep.sequenceNumber);
-        swapl(&rep->length);
+        swapl(&rep.length);
-        swaps(&rep->x);
+        swaps(&rep.x);
-        swaps(&rep->y);
+        swaps(&rep.y);
-        swaps(&rep->width);
+        swaps(&rep.width);
-        swaps(&rep->height);
+        swaps(&rep.height);
-        swaps(&rep->xhot);
+        swaps(&rep.xhot);
-        swaps(&rep->yhot);
+        swaps(&rep.yhot);
-        swapl(&rep->cursorSerial);
+        swapl(&rep.cursorSerial);
         SwapLongs(image, npixels);
     }
-    WriteToClient(client,
+    WriteToClient(client, sizeof(rep), &rep);
-                  sizeof(xXFixesGetCursorImageReply) + (npixels << 2), rep);
+    WriteToClient(client, npixels * sizeof(CARD32), image);
-    free(rep);
+    free(image);
     return Success;
 }
 
@@ -440,9 +440,9 @@ SProcXFixesSetCursorName(ClientPtr client)
 int
 ProcXFixesGetCursorName(ClientPtr client)
 {
-    CursorPtr pCursor;
-
     REQUEST(xXFixesGetCursorNameReq);
+
+    CursorPtr pCursor;
     const char *str;
     int len;
 
@@ -487,10 +487,9 @@ ProcXFixesGetCursorImageAndName(ClientPtr client)
 {
 /*    REQUEST(xXFixesGetCursorImageAndNameReq); */
     CursorPtr pCursor;
-    CARD32 *image;
     int npixels;
     const char *name;
-    int nbytes, nbytesRound;
+    int nbytes;
     int width, height;
     int rc, x, y;
 
@@ -508,47 +507,48 @@ ProcXFixesGetCursorImageAndName(ClientPtr client)
     npixels = width * height;
     name = pCursor->name ? NameForAtom(pCursor->name) : "";
     nbytes = strlen(name);
-    nbytesRound = pad_to_int32(nbytes);
 
-    xXFixesGetCursorImageAndNameReply *rep = calloc(1,
+    // pixmap plus name (padded to 4 bytes)
-                 sizeof(xXFixesGetCursorImageAndNameReply) +
+    const size_t image_size = (npixels + bytes_to_int32(nbytes)) * sizeof(CARD32);
-                 npixels * sizeof(CARD32) + nbytesRound);
+    CARD32 *image = calloc(1, image_size);
-    if (!rep)
+    if (!image)
         return BadAlloc;
 
-    rep->type = X_Reply;
-    rep->sequenceNumber = client->sequence;
-    rep->length = npixels + bytes_to_int32(nbytesRound);
-    rep->width = width;
-    rep->height = height;
-    rep->x = x;
-    rep->y = y;
-    rep->xhot = pCursor->bits->xhot;
-    rep->yhot = pCursor->bits->yhot;
-    rep->cursorSerial = pCursor->serialNumber;
-    rep->cursorName = pCursor->name;
-    rep->nbytes = nbytes;
-
-    image = (CARD32 *) (rep + 1);
     CopyCursorToImage(pCursor, image);
     memcpy((image + npixels), name, nbytes);
+
+    xXFixesGetCursorImageAndNameReply rep = {
+        .type = X_Reply,
+        .sequenceNumber = client->sequence,
+        .length = bytes_to_int32(image_size),
+        .width = width,
+        .height = height,
+        .x = x,
+        .y = y,
+        .xhot = pCursor->bits->xhot,
+        .yhot = pCursor->bits->yhot,
+        .cursorSerial = pCursor->serialNumber,
+        .cursorName = pCursor->name,
+        .nbytes = nbytes,
+    };
+
     if (client->swapped) {
-        swaps(&rep->sequenceNumber);
+        swaps(&rep.sequenceNumber);
-        swapl(&rep->length);
+        swapl(&rep.length);
-        swaps(&rep->x);
+        swaps(&rep.x);
-        swaps(&rep->y);
+        swaps(&rep.y);
-        swaps(&rep->width);
+        swaps(&rep.width);
-        swaps(&rep->height);
+        swaps(&rep.height);
-        swaps(&rep->xhot);
+        swaps(&rep.xhot);
-        swaps(&rep->yhot);
+        swaps(&rep.yhot);
-        swapl(&rep->cursorSerial);
+        swapl(&rep.cursorSerial);
-        swapl(&rep->cursorName);
+        swapl(&rep.cursorName);
-        swaps(&rep->nbytes);
+        swaps(&rep.nbytes);
         SwapLongs(image, npixels);
     }
-    WriteToClient(client, sizeof(xXFixesGetCursorImageAndNameReply) +
+    WriteToClient(client, sizeof(rep), &rep);
-                  (npixels << 2) + nbytesRound, rep);
+    WriteToClient(client, image_size, image);
-    free(rep);
+    free(image);
     return Success;
 }
 

xfixes/disconnect.c

@@ -87,21 +87,20 @@ int
 ProcXFixesGetClientDisconnectMode(ClientPtr client)
 {
     ClientDisconnectPtr pDisconnect = GetClientDisconnect(client);
-    xXFixesGetClientDisconnectModeReply reply;
 
     REQUEST_SIZE_MATCH(xXFixesGetClientDisconnectModeReq);
 
-    reply = (xXFixesGetClientDisconnectModeReply) {
+    xXFixesGetClientDisconnectModeReply rep = {
         .type = X_Reply,
         .sequenceNumber = client->sequence,
         .length = 0,
         .disconnect_mode = pDisconnect->disconnect_mode,
     };
     if (client->swapped) {
-        swaps(&reply.sequenceNumber);
+        swaps(&rep.sequenceNumber);
-        swapl(&reply.disconnect_mode);
+        swapl(&rep.disconnect_mode);
     }
-    WriteToClient(client, sizeof(xXFixesGetClientDisconnectModeReply), &reply);
+    WriteToClient(client, sizeof(rep), &rep);
 
     return Success;
 }

xfixes/region.c

@@ -509,8 +509,6 @@ int
 ProcXFixesFetchRegion(ClientPtr client)
 {
     RegionPtr pRegion;
-    xXFixesFetchRegionReply *reply;
-    xRectangle *pRect;
     BoxPtr pExtent;
     BoxPtr pBox;
     int i, nBox;
@@ -524,37 +522,39 @@ ProcXFixesFetchRegion(ClientPtr client)
     pBox = RegionRects(pRegion);
     nBox = RegionNumRects(pRegion);
 
-    reply = calloc(sizeof(xXFixesFetchRegionReply) + nBox * sizeof(xRectangle),
+    xRectangle *pRect = calloc(nBox, sizeof(xRectangle));
-                   1);
+    if (!pRect)
-    if (!reply)
         return BadAlloc;
-    reply->type = X_Reply;
-    reply->sequenceNumber = client->sequence;
-    reply->length = nBox << 1;
-    reply->x = pExtent->x1;
-    reply->y = pExtent->y1;
-    reply->width = pExtent->x2 - pExtent->x1;
-    reply->height = pExtent->y2 - pExtent->y1;
 
-    pRect = (xRectangle *) (reply + 1);
     for (i = 0; i < nBox; i++) {
         pRect[i].x = pBox[i].x1;
         pRect[i].y = pBox[i].y1;
         pRect[i].width = pBox[i].x2 - pBox[i].x1;
         pRect[i].height = pBox[i].y2 - pBox[i].y1;
     }
+
+    xXFixesFetchRegionReply rep = {
+        .type = X_Reply,
+        .sequenceNumber = client->sequence,
+        .length = nBox << 1,
+        .x = pExtent->x1,
+        .y = pExtent->y1,
+        .width = pExtent->x2 - pExtent->x1,
+        .height = pExtent->y2 - pExtent->y1,
+    };
+
     if (client->swapped) {
-        swaps(&reply->sequenceNumber);
+        swaps(&rep.sequenceNumber);
-        swapl(&reply->length);
+        swapl(&rep.length);
-        swaps(&reply->x);
+        swaps(&rep.x);
-        swaps(&reply->y);
+        swaps(&rep.y);
-        swaps(&reply->width);
+        swaps(&rep.width);
-        swaps(&reply->height);
+        swaps(&rep.height);
         SwapShorts((INT16 *) pRect, nBox * 4);
     }
-    WriteToClient(client, sizeof(xXFixesFetchRegionReply) +
+    WriteToClient(client, sizeof(rep), &rep);
-                         nBox * sizeof(xRectangle), (char *) reply);
+    WriteToClient(client, nBox * sizeof(xRectangle), pRect);
-    free(reply);
+    free(pRect);
     return Success;
 }