rust: error: `impl Debug` for `Error` with `errname()` integration
Integrate the `Error` type with `errname()` by providing a new
`name()` method.
Then, implement `Debug` for the type using the new method.
[ Miguel: under `CONFIG_SYMBOLIC_ERRNAME=n`, `errname()` is a
`static inline`, so added a helper to support that case,
like we had in the `rust` branch. Also moved `#include` up
and reworded commit message for clarity. ]
Co-developed-by: Wedson Almeida Filho <walmeida@microsoft.com>
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com>
Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com>
Signed-off-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Link: https://lore.kernel.org/r/20230531174450.3733220-1-aliceryhl@google.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs
index 7c1ce2b..05fcab6 100644
--- a/rust/kernel/error.rs
+++ b/rust/kernel/error.rs
@@ -4,12 +4,15 @@
//!
//! C header: [`include/uapi/asm-generic/errno-base.h`](../../../include/uapi/asm-generic/errno-base.h)
+use crate::str::CStr;
+
use alloc::{
alloc::{AllocError, LayoutError},
collections::TryReserveError,
};
use core::convert::From;
+use core::fmt;
use core::num::TryFromIntError;
use core::str::Utf8Error;
@@ -133,6 +136,42 @@ pub(crate) fn to_ptr<T>(self) -> *mut T {
// SAFETY: self.0 is a valid error due to its invariant.
unsafe { bindings::ERR_PTR(self.0.into()) as *mut _ }
}
+
+ /// Returns a string representing the error, if one exists.
+ #[cfg(not(testlib))]
+ pub fn name(&self) -> Option<&'static CStr> {
+ // SAFETY: Just an FFI call, there are no extra safety requirements.
+ let ptr = unsafe { bindings::errname(-self.0) };
+ if ptr.is_null() {
+ None
+ } else {
+ // SAFETY: The string returned by `errname` is static and `NUL`-terminated.
+ Some(unsafe { CStr::from_char_ptr(ptr) })
+ }
+ }
+
+ /// Returns a string representing the error, if one exists.
+ ///
+ /// When `testlib` is configured, this always returns `None` to avoid the dependency on a
+ /// kernel function so that tests that use this (e.g., by calling [`Result::unwrap`]) can still
+ /// run in userspace.
+ #[cfg(testlib)]
+ pub fn name(&self) -> Option<&'static CStr> {
+ None
+ }
+}
+
+impl fmt::Debug for Error {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ match self.name() {
+ // Print out number if no name can be found.
+ None => f.debug_tuple("Error").field(&-self.0).finish(),
+ // SAFETY: These strings are ASCII-only.
+ Some(name) => f
+ .debug_tuple(unsafe { core::str::from_utf8_unchecked(name) })
+ .finish(),
+ }
+ }
}
impl From<AllocError> for Error {
