Workaround X server bug, fd.o #3210: if a GLXGetFBConfigs request is sent, fix the length field in the reply.

src/xcb_in.c

@@ -35,6 +35,11 @@
 #include "xcbext.h"
 #include "xcbint.h"
 
+typedef struct {
+    unsigned int request;
+    enum workarounds workaround;
+} pending_reply;
+
 typedef struct XCBReplyData {
     unsigned int request;
     void *data;
@@ -200,7 +205,9 @@ int _xcb_in_init(_xcb_in *in)
     in->replies = _xcb_map_new();
     in->events = _xcb_queue_new();
     in->readers = _xcb_list_new();
-    if(!in->current_reply || !in->replies || !in->events || !in->readers)
+
+    in->pending_replies = _xcb_queue_new();
+    if(!in->current_reply || !in->replies || !in->events || !in->readers || !in->pending_replies)
         return 0;
 
     return 1;
@@ -213,11 +220,24 @@ void _xcb_in_destroy(_xcb_in *in)
     _xcb_map_delete(in->replies, free);
     _xcb_queue_delete(in->events, free);
     _xcb_list_delete(in->readers, 0);
+    _xcb_queue_delete(in->pending_replies, free);
 }
 
-int _xcb_in_expect_reply(XCBConnection *c, unsigned int request)
+int _xcb_in_expect_reply(XCBConnection *c, unsigned int request, enum workarounds workaround)
 {
-    /* XXX: currently a no-op */
+    if(workaround != WORKAROUND_NONE)
+    {
+        pending_reply *pend = malloc(sizeof(pending_reply));
+        if(!pend)
+            return 0;
+        pend->request = request;
+        pend->workaround = workaround;
+        if(!_xcb_queue_enqueue(c->in.pending_replies, pend))
+        {
+            free(pend);
+            return 0;
+        }
+    }
     return 1;
 }
 
@@ -234,21 +254,7 @@ int _xcb_in_read_packet(XCBConnection *c)
     /* Get the response type, length, and sequence number. */
     memcpy(&genrep, c->in.queue, sizeof(genrep));
 
-    /* For reply packets, check that the entire packet is available. */
-    if(genrep.response_type == 1)
-        length += genrep.length * 4;
-
-    buf = malloc(length);
-    if(!buf)
-        return 0;
-    if(_xcb_in_read_block(c, buf, length) <= 0)
-    {
-        free(buf);
-        return 0;
-    }
-
     /* Compute 32-bit sequence number of this packet. */
-    /* XXX: do "sequence lost" check here */
     if((genrep.response_type & 0x7f) != KeymapNotify)
     {
         int lastread = c->in.request_read;
@@ -262,6 +268,37 @@ int _xcb_in_read_packet(XCBConnection *c)
             c->in.request_read += 0x10000;
     }
 
+    /* For reply packets, check that the entire packet is available. */
+    if(genrep.response_type == 1)
+    {
+        pending_reply *pend = _xcb_list_peek_head(c->in.pending_replies);
+        if(pend && pend->request == c->in.request_read)
+        {
+            switch(pend->workaround)
+            {
+            case WORKAROUND_NONE:
+                break;
+            case WORKAROUND_GLX_GET_FB_CONFIGS_BUG:
+                {
+                    CARD32 *p = (CARD32 *) c->in.queue;
+                    genrep.length = p[2] * p[3] * 2;
+                }
+                break;
+            }
+            free(_xcb_queue_dequeue(c->in.pending_replies));
+        }
+        length += genrep.length * 4;
+    }
+
+    buf = malloc(length);
+    if(!buf)
+        return 0;
+    if(_xcb_in_read_block(c, buf, length) <= 0)
+    {
+        free(buf);
+        return 0;
+    }
+
     if(buf[0] == 1) /* response is a reply */
     {
         XCBReplyData *reader = _xcb_list_find(c->in.readers, match_reply, &c->in.request_read);

src/xcb_out.c

@@ -75,6 +75,7 @@ int XCBSendRequest(XCBConnection *c, unsigned int *request, struct iovec *vector
     struct iovec prefix[2];
     CARD16 shortlen = 0;
     CARD32 longlen = 0;
+    enum workarounds workaround = WORKAROUND_NONE;
 
     assert(c != 0);
     assert(request != 0);
@@ -121,6 +122,12 @@ int XCBSendRequest(XCBConnection *c, unsigned int *request, struct iovec *vector
         assert(extension && extension->present);
         ((CARD8 *) prefix[0].iov_base)[0] = extension->major_opcode;
         ((CARD8 *) prefix[0].iov_base)[1] = req->opcode;
+
+        /* do we need to work around the X server bug described in glx.xml? */
+        if(strcmp(req->ext->name, "GLX") &&
+                ((req->opcode == 17 && ((CARD32 *) vector[0].iov_base)[0] == 0x10004) ||
+                 req->opcode == 21))
+            workaround = WORKAROUND_GLX_GET_FB_CONFIGS_BUG;
     }
     else
         ((CARD8 *) prefix[0].iov_base)[0] = req->opcode;
@@ -136,7 +143,7 @@ int XCBSendRequest(XCBConnection *c, unsigned int *request, struct iovec *vector
     *request = ++c->out.request;
 
     if(!req->isvoid)
-        _xcb_in_expect_reply(c, *request);
+        _xcb_in_expect_reply(c, *request, workaround);
 
     ret = _xcb_out_write_block(c, prefix, i);
     if(ret > 0)

src/xcbint.h

@@ -38,6 +38,11 @@
     _xcb_assert_sequence_less((c)->out.request_written, (c)->out.request); \
 } while(0)
 
+enum workarounds {
+    WORKAROUND_NONE,
+    WORKAROUND_GLX_GET_FB_CONFIGS_BUG
+};
+
 /* xcb_list.c */
 
 typedef struct _xcb_list _xcb_list;
@@ -125,12 +130,14 @@ typedef struct _xcb_in {
     _xcb_map *replies;
     _xcb_queue *events;
     _xcb_list *readers;
+
+    _xcb_queue *pending_replies;
 } _xcb_in;
 
 int _xcb_in_init(_xcb_in *in);
 void _xcb_in_destroy(_xcb_in *in);
 
-int _xcb_in_expect_reply(XCBConnection *c, unsigned int request);
+int _xcb_in_expect_reply(XCBConnection *c, unsigned int request, enum workarounds workaround);
 
 int _xcb_in_read_packet(XCBConnection *c);
 int _xcb_in_read(XCBConnection *c);