Do not allow a script to attach a prim if its being sat upon.

This prevents a stack overflow where a get position on the avatar will refer to the attachment which will in turn refer back to the avatar.
This required recording of all sitting avatars on a prim which is done separately from recording the sit target avatar.
Recording HashSet is null if there are no sitting avatars in order to save memory.

1 files changed, 9 insertions, 0 deletions

diff --git a/OpenSim/Region/CoreModules/Avatar/Attachments/AttachmentsModule.cs b/OpenSim/Region/CoreModules/Avatar/Attachments/AttachmentsModule.cs
index 9eb0e38..eccf7a6 100644
--- a/OpenSim/Region/CoreModules/Avatar/Attachments/AttachmentsModule.cs
+++ b/OpenSim/Region/CoreModules/Avatar/Attachments/AttachmentsModule.cs
@@ -251,6 +251,15 @@ namespace OpenSim.Region.CoreModules.Avatar.Attachments
 //                m_log.DebugFormat(
 //                    "[ATTACHMENTS MODULE]: Attaching object {0} {1} to {2} point {3} from ground (silent = {4})",
 //                    group.Name, group.LocalId, sp.Name, attachmentPt, silent);
+
+                if (group.GetSittingAvatarsCount() != 0)
+                {
+//                    m_log.WarnFormat(
+//                        "[ATTACHMENTS MODULE]: Ignoring request to attach {0} {1} to {2} on {3} since {4} avatars are still sitting on it",
+//                        group.Name, group.LocalId, sp.Name, attachmentPt, group.GetSittingAvatarsCount());
+    
+                    return false;
+                }
     
                 if (sp.GetAttachments(attachmentPt).Contains(group))
                 {