Wait for capabilities message from Xorg

This commit adds a stage into the Xorg connection status to wait for
the capabilities message from the Xorg server. This allows us to move
the xorgxrdp version check to xrdp from the X server for better
reporting to the user.

xup/xup.c

@@ -146,6 +146,72 @@ lib_data_in(struct trans *trans)
     return 0;
 }
 
+/******************************************************************************/
+/*
+ * Wait for module caps message from Xorg module
+ *
+ * This routine waits for the Xorg module to send a caps message.
+ *
+ * We use this to check the caps are compatible with us before we
+ * go for a fuull-on connect
+ */
+static int
+wait_for_module_caps_message(struct mod *mod)
+{
+    int robjs_count;
+    intptr_t robjs[10];
+
+    mod->caps_processing_status = E_CAPS_NOT_PROCESSED;
+
+    while (mod->caps_processing_status == E_CAPS_NOT_PROCESSED)
+    {
+        robjs_count = 0;
+        if (trans_get_wait_objs(mod->trans, robjs, &robjs_count) != 0)
+        {
+            LOG(LOG_LEVEL_ERROR, "Xorg module has dropped connection");
+            return 1;
+        }
+
+        // We don't need a big timeout here, as all the module has to do is
+        // turn around the version message.
+        int status = g_obj_wait(robjs, robjs_count, 0, 0, 3 * 1000);
+
+        if (status < 0)
+        {
+            LOG(LOG_LEVEL_ERROR, "No response from Xorg module before timeout");
+            return 1;
+        }
+
+        (void)trans_check_wait_objs(mod->trans);
+    }
+
+    return (mod->caps_processing_status == E_CAPS_OK) ? 0 : 1;
+}
+
+/******************************************************************************/
+/* return error */
+static int
+lib_send_client_info(struct mod *mod)
+{
+    struct stream *s;
+    int len;
+
+    LOG_DEVEL(LOG_LEVEL_TRACE, "lib_send_client_info:");
+    make_stream(s);
+    init_stream(s, 8192);
+    s_push_layer(s, iso_hdr, 4);
+    out_uint16_le(s, 104);
+    g_memcpy(s->p, &(mod->client_info), sizeof(mod->client_info));
+    s->p += sizeof(mod->client_info);
+    s_mark_end(s);
+    len = (int)(s->end - s->data);
+    s_pop_layer(s, iso_hdr);
+    out_uint32_le(s, len);
+    lib_send_copy(mod, s);
+    free_stream(s);
+    return 0;
+}
+
 /******************************************************************************/
 /* return error */
 static int
@@ -220,26 +286,32 @@ lib_mod_connect(struct mod *mod)
         free_stream(s);
         return 1;
     }
+
+    // Set the transport up
     mod->trans->si = mod->si;
     mod->trans->my_source = XRDP_SOURCE_MOD;
     mod->trans->is_term = mod->server_is_term;
+    mod->trans->trans_data_in = lib_data_in;
+    mod->trans->header_size = 8;
+    mod->trans->callback_data = mod;
+    mod->trans->no_stream_init_on_data_in = 1;
+    mod->trans->extra_flags = 1;
 
     /* Give the X server a bit of time to start */
-    if (trans_connect(mod->trans, mod->ip, con_port, 30 * 1000) == 0)
+    error = trans_connect(mod->trans, mod->ip, con_port, 30 * 1000);
+    if (error == 0)
     {
         LOG_DEVEL(LOG_LEVEL_INFO, "lib_mod_connect: connected to Xserver "
                   "(Xorg) sck %lld",
                   (long long) (mod->trans->sck));
+        if (socket_mode == TRANS_MODE_UNIX)
+        {
+            lib_mod_log_peer(mod);
+        }
     }
     else
     {
         mod->server_msg(mod, "connection problem, giving up", 0);
-        error = 1;
-    }
-
-    if (error == 0 && socket_mode == TRANS_MODE_UNIX)
-    {
-        lib_mod_log_peer(mod);
     }
 
     if (error == 0)
@@ -247,6 +319,16 @@ lib_mod_connect(struct mod *mod)
         error = send_server_version_message(mod, s);
     }
 
+    if (error == 0)
+    {
+        error = wait_for_module_caps_message(mod);
+    }
+
+    if (error == 0)
+    {
+        error = lib_send_client_info(mod);
+    }
+
     if (error == 0)
     {
         error = send_server_monitor_full_invalidate(
@@ -259,21 +341,14 @@ lib_mod_connect(struct mod *mod)
     {
         trans_delete(mod->trans);
         mod->trans = 0;
-        mod->server_msg(mod, "some problem", 0);
+        mod->server_msg(mod, "Error connecting to Xorg - check log", 0);
-        return 1;
     }
     else
     {
         mod->server_msg(mod, "connected ok", 0);
-        mod->trans->trans_data_in = lib_data_in;
-        mod->trans->header_size = 8;
-        mod->trans->callback_data = mod;
-        mod->trans->no_stream_init_on_data_in = 1;
-        mod->trans->extra_flags = 1;
     }
-
     LOG_DEVEL(LOG_LEVEL_TRACE, "out lib_mod_connect");
-    return 0;
+    return error;
 }
 
 /******************************************************************************/
@@ -1708,30 +1783,6 @@ lib_mod_process_orders(struct mod *mod, int type, struct stream *s)
     return rv;
 }
 
-/******************************************************************************/
-/* return error */
-static int
-lib_send_client_info(struct mod *mod)
-{
-    struct stream *s;
-    int len;
-
-    LOG_DEVEL(LOG_LEVEL_TRACE, "lib_send_client_info:");
-    make_stream(s);
-    init_stream(s, 8192);
-    s_push_layer(s, iso_hdr, 4);
-    out_uint16_le(s, 104);
-    g_memcpy(s->p, &(mod->client_info), sizeof(mod->client_info));
-    s->p += sizeof(mod->client_info);
-    s_mark_end(s);
-    len = (int)(s->end - s->data);
-    s_pop_layer(s, iso_hdr);
-    out_uint32_le(s, len);
-    lib_send_copy(mod, s);
-    free_stream(s);
-    return 0;
-}
-
 /******************************************************************************/
 /* return error */
 static int
@@ -1743,6 +1794,7 @@ lib_mod_process_message(struct mod *mod, struct stream *s)
     int len;
     int type;
     char *phold;
+    int version;
 
     int width;
     int height;
@@ -1769,6 +1821,7 @@ lib_mod_process_message(struct mod *mod, struct stream *s)
     }
     else if (type == 2) /* caps */
     {
+        mod->caps_processing_status = E_CAPS_OK;   /* Assume all OK */
         LOG_DEVEL(LOG_LEVEL_TRACE,
                   "lib_mod_process_message: type 2 len %d", len);
         for (index = 0; index < num_orders; index++)
@@ -1779,6 +1832,20 @@ lib_mod_process_message(struct mod *mod, struct stream *s)
 
             switch (type)
             {
+                case 100:
+                    in_uint32_le(s, version);
+                    if (version != CLIENT_INFO_CURRENT_VERSION)
+                    {
+                        LOG(LOG_LEVEL_ERROR,
+                            "Xorg module has version %d, expected %d",
+                            version, CLIENT_INFO_CURRENT_VERSION);
+                        mod->server_msg(mod,
+                                        "Xorg module has wrong version number",
+                                        0);
+                        mod->caps_processing_status = E_CAPS_NOT_OK;
+                    }
+                    break;
+
                 default:
                     LOG_DEVEL(LOG_LEVEL_TRACE,
                               "lib_mod_process_message: unknown"
@@ -1788,7 +1855,6 @@ lib_mod_process_message(struct mod *mod, struct stream *s)
             }
             s->p = phold + len;
         }
-        lib_send_client_info(mod);
     }
     else if (type == 3) /* order list with len after type */
     {

xup/xup.h

@@ -21,6 +21,17 @@
 #ifndef XUP_H
 #define XUP_H
 
+/**
+ * Enum for the states used to process a
+ * capabilities message from the Xorg module
+ */
+enum caps_processing_status
+{
+    E_CAPS_NOT_PROCESSED, ///< Capabilities mesage from module not processed
+    E_CAPS_OK,            ///< Capabilities are OK
+    E_CAPS_NOT_OK         ///< Capabilities are not OK
+};
+
 /* include other h files */
 #include "arch.h"
 #include "parse.h"
@@ -202,6 +213,7 @@ struct mod
     char *screen_shmem_pixels;
     struct trans *trans;
     char keycode_set[32];
+    enum caps_processing_status caps_processing_status;
 };
 
 #endif // XUP_H