Playernames and chunks

[WaitingToCompile]

So I'm working on a mod that includes a chunkloader block and I have a few questions.

1- how would I find to coordinates of a chunk from the coordinates of a block in that chunk

2- how do I find the name of a player when they try to place something and stop them from placing it if they have a certain name (so that server admins can blacklist some players from using chunkloaders)

 

I'm pretty new to forge modding and I'm not massively proficient at java (my most ambitious non minecraft java project being a text based adventure game that I haven't finished yet) and I've probably overlooked something really obvious

[keepcalm]

I'm pretty sure there's a function something like getChunkFromBlockCoords in World, that might be a good place to start, and as for the player's username, perhaps try using Block.onBlockPlacedBy and check if it's an EntityPlayer?