From 3844146a2163a394d3f6126b4ebf6eb5e5ba2dc2 Mon Sep 17 00:00:00 2001
From: Jay Bosamiya <jayb@microsoft.com>
Date: Tue, 21 Apr 2026 17:14:43 -0700
Subject: [PATCH] More unsafe removal

---
 litebox_shim_linux/src/syscalls/tests.rs | 63 +++++++-----------------
 1 file changed, 18 insertions(+), 45 deletions(-)

diff --git a/litebox_shim_linux/src/syscalls/tests.rs b/litebox_shim_linux/src/syscalls/tests.rs
index cd58df3dc..0bf1843fd 100644
--- a/litebox_shim_linux/src/syscalls/tests.rs
+++ b/litebox_shim_linux/src/syscalls/tests.rs
@@ -5,6 +5,7 @@ use litebox::fs::{FileSystem as _, Mode, OFlags};
 use litebox::platform::RawConstPointer as _;
 use litebox_common_linux::{AtFlags, EfdFlags, FcntlArg, FileDescriptorFlags, errno::Errno};
 use litebox_platform_multiplex::{Platform, set_platform};
+use zerocopy::FromBytes as _;
 
 use crate::MutPtr;
 
@@ -179,22 +180,8 @@ fn test_getdent64() {
     let mut found_entries = alloc::vec::Vec::new();
 
     while offset < bytes_read {
-        assert!(
-            unsafe { buffer.as_ptr().add(offset) }.addr()
-                & (core::mem::align_of::<litebox_common_linux::LinuxDirent64>() - 1)
-                == 0,
-            "Pointer at offset {} is not aligned for LinuxDirent64 (requires {}-byte alignment)",
-            offset,
-            core::mem::align_of::<litebox_common_linux::LinuxDirent64>()
-        );
-        let dirent = unsafe {
-            core::ptr::read_unaligned(
-                buffer
-                    .as_ptr()
-                    .add(offset)
-                    .cast::<litebox_common_linux::LinuxDirent64>(),
-            )
-        };
+        let (dirent, _) =
+            litebox_common_linux::LinuxDirent64::read_from_prefix(&buffer[offset..]).unwrap();
 
         // Validate the entry length
         assert!(dirent.len > 0, "Directory entry length must be positive");
@@ -203,14 +190,11 @@ fn test_getdent64() {
             "Entry should not exceed buffer"
         );
 
-        let name_ptr = unsafe {
-            buffer
-                .as_ptr()
-                .add(offset + core::mem::offset_of!(litebox_common_linux::LinuxDirent64, __name))
+        let name_bytes = {
+            let start = offset + core::mem::offset_of!(litebox_common_linux::LinuxDirent64, __name);
+            let end = offset + dirent.len as usize;
+            &buffer[start..end]
         };
-        let name_len = dirent.len as usize
-            - core::mem::offset_of!(litebox_common_linux::LinuxDirent64, __name);
-        let name_bytes = unsafe { core::slice::from_raw_parts(name_ptr, name_len) };
 
         // Find the null terminator
         let null_pos = name_bytes
@@ -281,13 +265,8 @@ fn test_getdent64() {
     assert!(bytes <= small_buffer.len(), "Should not exceed buffer size");
     // If bytes > 0, verify the structure is valid
     if bytes > 0 {
-        let dirent = unsafe {
-            core::ptr::read_unaligned(
-                small_buffer
-                    .as_ptr()
-                    .cast::<litebox_common_linux::LinuxDirent64>(),
-            )
-        };
+        let (dirent, _) =
+            litebox_common_linux::LinuxDirent64::read_from_prefix(&small_buffer[..bytes]).unwrap();
         assert!(
             dirent.len as usize <= bytes,
             "First entry length should fit in returned bytes"
@@ -358,14 +337,10 @@ fn test_getdent64() {
         // Parse entries from this chunk
         let mut offset = 0;
         while offset < bytes_read {
-            let dirent = unsafe {
-                core::ptr::read_unaligned(
-                    chunk_buffer
-                        .as_ptr()
-                        .add(offset)
-                        .cast::<litebox_common_linux::LinuxDirent64>(),
-                )
-            };
+            let (dirent, _) = litebox_common_linux::LinuxDirent64::read_from_prefix(
+                &chunk_buffer[offset..bytes_read],
+            )
+            .unwrap();
 
             assert!(dirent.len > 0, "Entry length must be positive");
             assert!(
@@ -373,14 +348,12 @@ fn test_getdent64() {
                 "Entry should fit in chunk"
             );
 
-            let name_ptr = unsafe {
-                chunk_buffer.as_ptr().add(
-                    offset + core::mem::offset_of!(litebox_common_linux::LinuxDirent64, __name),
-                )
+            let name_bytes = {
+                let start =
+                    offset + core::mem::offset_of!(litebox_common_linux::LinuxDirent64, __name);
+                let end = offset + dirent.len as usize;
+                &chunk_buffer[start..end]
             };
-            let name_len = dirent.len as usize
-                - core::mem::offset_of!(litebox_common_linux::LinuxDirent64, __name);
-            let name_bytes = unsafe { core::slice::from_raw_parts(name_ptr, name_len) };
 
             let null_pos = name_bytes
                 .iter()