Implement Display and Debug for CStr

Signed-off-by: Morgan Bartlett <mjmouse9999@gmail.com>

Author: mbartlett21

rust/kernel/str.rs

@@ -2,6 +2,7 @@
 
 //! String representations.
 
+use core::fmt::{self, Write};
 use core::ops::{self, Deref, Index};
 
 use crate::bindings;
@@ -209,6 +210,35 @@ impl CStr {
     }
 }
 
+impl fmt::Display for CStr {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        for &c in self.as_bytes() {
+            if (0x20..0x7f).contains(&c) {
+                // Printable character
+                f.write_char(c as char)?;
+            } else {
+                write!(f, "\\x{:02x}", c)?;
+            }
+        }
+        Ok(())
+    }
+}
+
+impl fmt::Debug for CStr {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str("\"")?;
+        for &c in self.as_bytes() {
+            if (0x20..0x7f).contains(&c) {
+                // Printable character
+                f.write_char(c as char)?;
+            } else {
+                write!(f, "\\x{:02x}", c)?;
+            }
+        }
+        f.write_str("\"")
+    }
+}
+
 impl AsRef<BStr> for CStr {
     #[inline]
     fn as_ref(&self) -> &BStr {