diff --git a/api/src/index.js b/api/src/index.js
index d628ba1..d9a5cae 100644
--- a/api/src/index.js
+++ b/api/src/index.js
@@ -20,7 +20,7 @@ app.post(
                 errorMessage: 'Supplied language is not a string',
             },
             custom: {
-                options: value => languages.find(language => language.aliases.includes(value?.toLowerCase())),
+                options: value => value && languages.find(language => language.aliases.includes(value.toLowerCase())),
                 errorMessage: 'Supplied language is not supported by Piston',
             },
         },
diff --git a/lxc/execute b/lxc/execute
index 3438547..29c445b 100755
--- a/lxc/execute
+++ b/lxc/execute
@@ -45,13 +45,17 @@ timeout -s KILL 20 \
 
 # process janitor
 lxc-attach --clear-env -n piston -- \
-    /bin/bash -l -c "\
-        for i in {1..100}; do pkill -u runner$newinc --signal SIGKILL; done ;\
-        find /tmp -user runner$newinc -exec /bin/rm -rf {} \; ;\
-        find /var/tmp -user runner$newinc -exec /bin/rm -rf {} \; ;\
-        find /var/lock -user runner$newinc -exec /bin/rm -rf {} \; ;\
-        find /dev/shm -user runner$newinc -exec /bin/rm -rf {} \; ;\
-        find /run/lock -user runner$newinc -exec /bin/rm -rf {} \; ;\
-        " > /dev/null 2>&1 &
+    /bin/bash -l -c "
+        for i in {1..100}
+        do
+            pkill -u runner$newinc --signal SIGKILL
+        done
+
+        find /tmp -user runner$newinc -delete
+        find /var/tmp -user runner$newinc -delete
+        find /var/lock -user runner$newinc -delete
+        find /dev/shm -user runner$newinc -delete
+        find /run/lock -user runner$newinc -delete
+    " > /dev/null 2>&1 &
 
 rm -rf $basepath/tmp/$epoch
diff --git a/lxc/executors/paradoc b/lxc/executors/paradoc
index 33fe880..08e6e2c 100755
--- a/lxc/executors/paradoc
+++ b/lxc/executors/paradoc
@@ -1,2 +1,6 @@
-cd /tmp/$2
-runuser runner$1 -c "cd /tmp/$2 ; timeout -s KILL 3 python3 -m paradoc code.code <<< args.args"
+#!/bin/bash
+
+runuser runner$1 -c "
+    cd /tmp/$2
+    timeout -s KILL 3 python3 -m paradoc code.code < args.args
+"
diff --git a/lxc/executors/rust b/lxc/executors/rust
index 2a70609..9dc32ea 100755
--- a/lxc/executors/rust
+++ b/lxc/executors/rust
@@ -1,9 +1,7 @@
 #!/bin/bash
 
-cd /tmp/$2
-rustc -o binary code.code
-
 runuser runner$1 -c "
     cd /tmp/$2
+    rustc -o binary code.code
     timeout -s KILL 3 xargs -a args.args -d '\n' ./binary < stdin.stdin
 "