[fix] fix user stack alignment

src/user_stack.rs

@@ -85,7 +85,15 @@ fn init_stack(args: &[String], envs: &[String], auxv: &mut [AuxvEntry], sp: usiz
     stack.push(padding_null.as_bytes(), &mut data);
 
     stack.push("\0".repeat(stack.get_sp() % 16).as_bytes(), &mut data);
-    assert!(stack.get_sp() % 16 == 0);
+
+    // next things are auxv entries, envp and argv pointers, argc
+    // auxv entries is 16 bytes each, aligned to 16 bytes
+    // envp and argv pointers, argc is 8 bytes each, aligned to 8 bytes
+    let pointers_count = auxv.len() + envs.len() + args.len() + 3;
+    if pointers_count % 2 != 0 {
+        stack.push(padding_null.as_bytes(), &mut data);
+    }
+
     // Push auxiliary vectors
     for auxv_entry in auxv.iter_mut() {
         if auxv_entry.get_type() == AuxvType::RANDOM {
@@ -112,6 +120,7 @@ fn init_stack(args: &[String], envs: &[String], auxv: &mut [AuxvEntry], sp: usiz
     stack.push_usize_slice(argv_slice.as_slice(), &mut data);
     // Push argc
     stack.push_usize_slice(&[args.len()], &mut data);
+    assert!(stack.get_sp() % 16 == 0);
     data
 }