From 15d8b58120669554bab787800906bdae09a58bde Mon Sep 17 00:00:00 2001
From: David Carlier <devnexen@gmail.com>
Date: Thu, 5 Dec 2024 23:18:38 +0000
Subject: [PATCH] addressing remarks

---
 src/helpers.rs         | 15 +++++++++++++++
 src/shims/unix/fs.rs   | 27 ++++++++++++++++-----------
 tests/pass/shims/fs.rs | 15 ++++++---------
 3 files changed, 37 insertions(+), 20 deletions(-)

diff --git a/src/helpers.rs b/src/helpers.rs
index b57ce4e070..d440a143d7 100644
--- a/src/helpers.rs
+++ b/src/helpers.rs
@@ -324,6 +324,21 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
         bug!("No field named {} in type {}", name, base.layout().ty);
     }
 
+    fn try_project_field_named<P: Projectable<'tcx, Provenance>>(
+        &self,
+        base: &P,
+        name: &str,
+    ) -> InterpResult<'tcx, Option<P>> {
+        let this = self.eval_context_ref();
+        let adt = base.layout().ty.ty_adt_def().unwrap();
+        for (idx, field) in adt.non_enum_variant().fields.iter().enumerate() {
+            if field.name.as_str() == name {
+                return interp_ok(Some(this.project_field(base, idx)?));
+            }
+        }
+        interp_ok(None)
+    }
+
     /// Search if `base` (which must be a struct or union type) contains the `name` field.
     fn projectable_has_field<P: Projectable<'tcx, Provenance>>(
         &self,
diff --git a/src/shims/unix/fs.rs b/src/shims/unix/fs.rs
index 387459be20..1b2ea64802 100644
--- a/src/shims/unix/fs.rs
+++ b/src/shims/unix/fs.rs
@@ -1072,7 +1072,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
             Some(Ok(dir_entry)) => {
                 // Write the directory entry into a newly allocated buffer.
                 // The name is written with write_bytes, while the rest of the
-                // dirent64 struct is written using write_int_fields.
+                // dirent64 (or dirent) struct is written using write_int_fields.
 
                 // For reference:
                 // pub struct dirent64 {
@@ -1082,6 +1082,13 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
                 //     pub d_type: c_uchar,
                 //     pub d_name: [c_char; 256],
                 // }
+                //
+                // pub struct dirent {
+                //     pub d_ino: ino64_t,
+                //     pub d_off: off64_t,
+                //     pub d_reclen: c_ushort,
+                //     pub d_name: [c_char; 3],
+                // }
 
                 let mut name = dir_entry.file_name(); // not a Path as there are no separators!
                 name.push("\0"); // Add a NUL terminator
@@ -1095,11 +1102,9 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
                 } else {
                     this.libc_ty_layout("dirent")
                 };
-                let d_name_offset = if is_linux {
-                    dirent64_layout.fields.offset(4 /* d_name */).bytes()
-                } else {
-                    dirent64_layout.fields.offset(3 /* d_name */).bytes()
-                };
+                let fields = &dirent64_layout.fields;
+                let fcount = (*fields).count().checked_sub(1).expect("invalid count");
+                let d_name_offset = (*fields).offset(fcount).bytes();
                 let size = d_name_offset.strict_add(name_len);
 
                 let entry = this.allocate_ptr(
@@ -1122,11 +1127,11 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
                     &this.ptr_to_mplace(entry, dirent64_layout),
                 )?;
 
-                if is_linux {
-                    this.write_int_fields_named(
-                        &[("d_type", file_type.into())],
-                        &this.ptr_to_mplace(entry, dirent64_layout),
-                    )?;
+                if let Some(d_type) = this.try_project_field_named(
+                    &this.ptr_to_mplace(entry, dirent64_layout),
+                    "d_type",
+                )? {
+                    this.write_int(file_type, &d_type)?;
                 }
 
                 let name_ptr = entry.wrapping_offset(Size::from_bytes(d_name_offset), this);
diff --git a/tests/pass/shims/fs.rs b/tests/pass/shims/fs.rs
index c3653d6657..0481a8f3dc 100644
--- a/tests/pass/shims/fs.rs
+++ b/tests/pass/shims/fs.rs
@@ -276,15 +276,12 @@ fn test_directory() {
             .collect::<BTreeMap<_, _>>()
     );
     // Deleting the directory should fail, since it is not empty.
-    let errno = if cfg!(any(target_os = "solaris", target_os = "illumos")) {
-        // Solaris/Illumos `rmdir` call set errno to EEXIST if directory contains
-        // other entries than `.` and `..`.
-        // https://docs.oracle.com/cd/E86824_01/html/E54765/rmdir-2.html
-        ErrorKind::AlreadyExists
-    } else {
-        ErrorKind::DirectoryNotEmpty
-    };
-    assert_eq!(errno, remove_dir(&dir_path).unwrap_err().kind());
+
+    // Solaris/Illumos `rmdir` call set errno to EEXIST if directory contains
+    // other entries than `.` and `..`.
+    // https://docs.oracle.com/cd/E86824_01/html/E54765/rmdir-2.html
+    let err = remove_dir(&dir_path).unwrap_err().kind();
+    assert!(err == ErrorKind::AlreadyExists || err == ErrorKind::DirectoryNotEmpty);
     // Clean up the files in the directory
     remove_file(&path_1).unwrap();
     remove_file(&path_2).unwrap();