Add the rust std as a custom sysroot

crates/shared/src/fs.rs

@@ -1,3 +1,7 @@
+use io::{IoBase, Read, Write};
+
+use crate::syscall;
+
 #[derive(Debug)]
 pub struct File {
     fd: u64,
@@ -6,7 +10,7 @@ pub struct File {
 impl File {
     /// # Safety
     /// The file descriptor must be valid
-    pub unsafe fn new(fd: u64) -> Self {
+    pub unsafe fn from_raw_fd(fd: u64) -> Self {
         Self { fd }
     }
 
@@ -14,3 +18,23 @@ impl File {
         self.fd
     }
 }
+
+impl IoBase for File {
+    type Error = ();
+}
+
+impl Read for File {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize, Self::Error> {
+        Ok(syscall::read(self.as_fd(), buf) as usize)
+    }
+}
+
+impl Write for File {
+    fn write(&mut self, buf: &[u8]) -> Result<usize, Self::Error> {
+        Ok(syscall::write(self.as_fd(), buf) as usize)
+    }
+
+    fn flush(&mut self) -> Result<(), Self::Error> {
+        todo!()
+    }
+}