Remove/Whitelist all bindings in Clojure - binding

Question

In my little game project, i want player to manipulate some in-game stuff writing some Clojure scripts right in the game. So, i downloaded Clojure lib and used this code:
private val eval = Clojure.`var`("clojure.core", "eval")
fun eval(code: String): Any? =
try {
eval.invoke(Clojure.read("(do $code)"))
} catch(e: Exception) {
e.printStackTrace()
null
}
but the thing is, by doing so player can manipulate the whole program, as it is runs in same environment, as the game code. The simplest example is (System/exit 0).
My question is - how to remove all Clojure bindings from my scripting context except some basic predefined stuff, like math operators, collection magic and so on?
Also, i can put my own bindings(for wiring these scripts to actual game logic) with eval.invoke("(def do-magic [x] (println "magic"))"), but is there a more consistent way to do this?
upd:
I need to do really simple stuff like math and jumping around with simple functions. Maybe a bit of collection magic. So i need to block everything except this stuff, so any unsafe code just cant exist at all.

Answer 1

This technique is called sandbox and simply googling "clojure sandbox" finally led me to the articles about this topic.
UPD:
I've needed to whitelist stuff, not blacklist as it was used on the internet.
Spent whole day, but finally got this to work properly
private val eval = Clojure.`var`("clojure.core", "eval")
val whitelist = listOf("+", "-", "*", "/", "=") // example
init {
val wh = whitelist.joinToString(" ", "[", "]") { "\"$it\"" }
eval("""
(let [wh (vec (map symbol $wh))]
(doseq [n (all-ns) :let [n (ns-name n)]]
(if (= (str n) "clojure.core")
(doseq [[k _] (ns-map n) :when (not (some (fn [x] (= x k)) wh))]
(ns-unmap n k))
(remove-ns n))))
""")
}
fun eval(code: String): Any? =
try {
eval.invoke(Clojure.read("(do $code)"))
} catch(e: Exception) {
e.printStackTrace()
null
}