let read_byte_helper take in io::Result<usize> too

Author: tiif

src/shims/unix/fd.rs

@@ -140,7 +140,7 @@ impl FileDescription for io::Stdin {
             // We want isolation mode to be deterministic, so we have to disallow all reads, even stdin.
             helpers::isolation_abort_error("`read` from stdin")?;
         }
-        let result = Ok(Read::read(&mut { self }, bytes));
+        let result = Read::read(&mut { self }, bytes);
         ecx.read_byte_helper(ptr, bytes.to_vec(), result, dest)?;
         Ok(())
     }
@@ -652,12 +652,12 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
         &mut self,
         buf: Pointer,
         bytes: Vec<u8>,
-        result: InterpResult<'tcx, io::Result<usize>>,
+        result: io::Result<usize>,
         dest: &MPlaceTy<'tcx>,
     ) -> InterpResult<'tcx> {
         let this = self.eval_context_mut();
         // `File::read` never returns a value larger than `count`, so this cannot fail.
-        match result?.map(|c| i64::try_from(c).unwrap()) {
+        match result.map(|c| i64::try_from(c).unwrap()) {
             // try to pass this the write_ptr inside write
             // Pass the pointer inside the write function.
             Ok(read_bytes) => {

src/shims/unix/fs.rs

@@ -40,7 +40,7 @@ impl FileDescription for FileHandle {
         ecx: &mut MiriInterpCx<'tcx>,
     ) -> InterpResult<'tcx> {
         assert!(communicate_allowed, "isolation should have prevented even opening a file");
-        let result = Ok((&mut &self.file).read(bytes));
+        let result = (&mut &self.file).read(bytes);
         ecx.read_byte_helper(ptr, bytes.to_vec(), result, dest)?;
         Ok(())
     }
@@ -82,7 +82,7 @@ impl FileDescription for FileHandle {
                 .expect("failed to restore file position, this shouldn't be possible");
             res
         };
-        let result = Ok(f());
+        let result = f();
         ecx.read_byte_helper(ptr, bytes.to_vec(), result, dest)?;
         Ok(())
     }

src/shims/unix/linux/eventfd.rs

@@ -69,15 +69,15 @@ impl FileDescription for Event {
     ) -> InterpResult<'tcx> {
         // Check the size of slice, and return error only if the size of the slice < 8.
         let Some(bytes) = bytes.first_chunk_mut::<U64_ARRAY_SIZE>() else {
-            let result = Ok(Err(Error::from(ErrorKind::InvalidInput)));
+            let result = Err(Error::from(ErrorKind::InvalidInput));
             ecx.read_byte_helper(ptr, bytes.to_vec(), result, dest)?;
             return Ok(());
         };
         // Block when counter == 0.
         let counter = self.counter.get();
         if counter == 0 {
             if self.is_nonblock {
-                let result = Ok(Err(Error::from(ErrorKind::WouldBlock)));
+                let result = Err(Error::from(ErrorKind::WouldBlock));
                 ecx.read_byte_helper(ptr, bytes.to_vec(), result, dest)?;
                 return Ok(());
             } else {
@@ -97,7 +97,7 @@ impl FileDescription for Event {
             // types for current file description.
             ecx.check_and_update_readiness(self_ref)?;
 
-            let result = Ok(Ok(U64_ARRAY_SIZE));
+            let result = Ok(U64_ARRAY_SIZE);
             ecx.read_byte_helper(ptr, bytes.to_vec(), result, dest)?;
             return Ok(());
         }

src/shims/unix/unnamed_socket.rs

@@ -135,7 +135,7 @@ impl FileDescription for AnonSocket {
 
         // Always succeed on read size 0.
         if request_byte_size == 0 {
-            let result = Ok(Ok(0));
+            let result = Ok(0);
             ecx.read_byte_helper(ptr, bytes.to_vec(), result, dest)?;
             return Ok(());
         }
@@ -150,7 +150,7 @@ impl FileDescription for AnonSocket {
             if self.peer_fd().upgrade().is_none() {
                 // Socketpair with no peer and empty buffer.
                 // 0 bytes successfully read indicates end-of-file.
-                let result = Ok(Ok(0));
+                let result = Ok(0);
                 ecx.read_byte_helper(ptr, bytes.to_vec(), result, dest)?;
                 return Ok(());
             } else {
@@ -160,7 +160,7 @@ impl FileDescription for AnonSocket {
                     // EAGAIN or EWOULDBLOCK can be returned for socket,
                     // POSIX.1-2001 allows either error to be returned for this case.
                     // Since there is no ErrorKind for EAGAIN, WouldBlock is used.
-                    let result = Ok(Err(Error::from(ErrorKind::WouldBlock)));
+                    let result = Err(Error::from(ErrorKind::WouldBlock));
                     ecx.read_byte_helper(ptr, bytes.to_vec(), result, dest)?;
                     return Ok(());
                 } else {
@@ -194,7 +194,7 @@ impl FileDescription for AnonSocket {
             ecx.check_and_update_readiness(&peer_fd)?;
         }
 
-        let result = Ok(Ok(actual_read_size));
+        let result = Ok(actual_read_size);
         ecx.read_byte_helper(ptr, bytes.to_vec(), result, dest)?;
         return Ok(());
     }