Save keys to file

src/main.rs

@@ -1,6 +1,8 @@
 use libc::{
-    c_int, c_void, mmap, MAP_ANON, MAP_FAILED, MAP_PRIVATE, MAP_SHARED, PROT_READ, PROT_WRITE,
+    c_int, c_void, mmap, MAP_FAILED, MAP_PRIVATE, MAP_SHARED, PROT_READ, PROT_WRITE,
 };
+use std::fs::File;
+use std::os::fd::AsRawFd;
 use std::{env, ptr};
 
 const SHARED_MEMORY_SIZE: usize = 1024;
@@ -45,13 +47,14 @@ fn main() {
     } as *mut u8;
     assert_ne!(sync_memory, MAP_FAILED as *mut u8);
 
+    let private_file = File::open(env::var("KEY_FILE").expect("KEY_FILE environment variable missing")).expect("Cannot open KEY_FILE");
     let private_mem = unsafe {
         mmap(
             ptr::null_mut() as *mut c_void,
             32 * 100,
             PROT_READ | PROT_WRITE,
-            MAP_PRIVATE | MAP_ANON,
-            0,
+            MAP_PRIVATE,
+            private_file.as_raw_fd(),
             0,
         )
     } as *mut u8;