diff --git a/helpers/enter-grain-source/Cargo.lock b/helpers/enter-grain-source/Cargo.lock
index 435954f..5194f00 100644
--- a/helpers/enter-grain-source/Cargo.lock
+++ b/helpers/enter-grain-source/Cargo.lock
@@ -1,4 +1,6 @@
-[root]
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
 name = "enter_grain"
 version = "0.1.0"
 dependencies = [
@@ -10,3 +12,5 @@ name = "syscall"
 version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[metadata]
+"checksum syscall 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "dae2c4de039bf338dd96f46621f20222c4101045dac5403b46f472608cb5b556"
diff --git a/helpers/enter-grain-source/src/main.rs b/helpers/enter-grain-source/src/main.rs
index 4cf7512..032e964 100644
--- a/helpers/enter-grain-source/src/main.rs
+++ b/helpers/enter-grain-source/src/main.rs
@@ -1,8 +1,6 @@
-#![feature(alloc_system)]
-extern crate alloc_system;
-
 // use std::env;
-use std::fs::File;
+use std::fs::{File, metadata};
+use std::os::unix::fs::MetadataExt;
 use std::io::Read;
 use std::ptr;
 use std::env;
@@ -74,13 +72,12 @@ fn wait_all_children() {
     }
 }
 
-fn setuid_setgid_1000() {
-    // These are the right UID & GID because they are what Sandstorm
-    // uses inside the user namespace.
-    let one_thousand = 1000usize;
+fn setuid_setgid() {
+    let meta = metadata("/var").unwrap();
+
     unsafe {
-        syscall!(SETUID, one_thousand);
-        syscall!(SETGID, one_thousand);
+        syscall!(SETUID, meta.uid());
+        syscall!(SETGID, meta.gid());
     }
 }
 
@@ -173,7 +170,7 @@ fn main() {
     let fork_result = fork();
     if fork_result == 0 {
         // in the child
-        setuid_setgid_1000();
+        setuid_setgid();
         execve_bash(result);
     } else {
         // in the parent
diff --git a/helpers/enter_grain b/helpers/enter_grain
index 9ae01f6..cdb2b82 100755
Binary files a/helpers/enter_grain and b/helpers/enter_grain differ
diff --git a/helpers/enter_grain.sha1 b/helpers/enter_grain.sha1
index aa29090..576232a 100644
--- a/helpers/enter_grain.sha1
+++ b/helpers/enter_grain.sha1
@@ -1 +1 @@
-11198904136a7e8079d41ef50af613d21786b5b8  enter_grain
+3e1a80bd7ca1f61de6b3044e904947264e6f6e53  enter_grain