From d2e3115d717197cb2bc020dd1f06b06538474ac3 Mon Sep 17 00:00:00 2001 From: Gary Guo Date: Wed, 31 May 2023 17:44:50 +0000 Subject: 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 Signed-off-by: Wedson Almeida Filho Co-developed-by: Sven Van Asbroeck Signed-off-by: Sven Van Asbroeck Signed-off-by: Gary Guo Signed-off-by: Alice Ryhl Reviewed-by: Martin Rodriguez Reboredo Link: https://lore.kernel.org/r/20230531174450.3733220-1-aliceryhl@google.com Signed-off-by: Miguel Ojeda --- rust/bindings/bindings_helper.h | 1 + rust/helpers.c | 7 +++++++ rust/kernel/error.rs | 39 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 47 insertions(+) (limited to 'rust') diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h index 50e7a76d5455..3e601ce2548d 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -6,6 +6,7 @@ * Sorted alphabetically. */ +#include #include #include #include diff --git a/rust/helpers.c b/rust/helpers.c index 81e80261d597..bb594da56137 100644 --- a/rust/helpers.c +++ b/rust/helpers.c @@ -21,6 +21,7 @@ #include #include #include +#include #include #include #include @@ -110,6 +111,12 @@ long rust_helper_PTR_ERR(__force const void *ptr) } EXPORT_SYMBOL_GPL(rust_helper_PTR_ERR); +const char *rust_helper_errname(int err) +{ + return errname(err); +} +EXPORT_SYMBOL_GPL(rust_helper_errname); + struct task_struct *rust_helper_get_current(void) { return current; diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs index 7c1ce2bccd08..05fcab6abfe6 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 @@ impl Error { // 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 for Error { -- cgit v1.2.3