Commit d2e3115d authored by Gary Guo's avatar Gary Guo Committed by Miguel Ojeda
Browse files

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: default avatarWedson Almeida Filho <walmeida@microsoft.com>
Signed-off-by: default avatarWedson Almeida Filho <walmeida@microsoft.com>
Co-developed-by: default avatarSven Van Asbroeck <thesven73@gmail.com>
Signed-off-by: default avatarSven Van Asbroeck <thesven73@gmail.com>
Signed-off-by: default avatarGary Guo <gary@garyguo.net>
Signed-off-by: default avatarAlice Ryhl <aliceryhl@google.com>
Reviewed-by: default avatarMartin Rodriguez Reboredo <yakoyoku@gmail.com>
Link: https://lore.kernel.org/r/20230531174450.3733220-1-aliceryhl@google.com


Signed-off-by: default avatarMiguel Ojeda <ojeda@kernel.org>
parent d09a6102

rust/bindings/bindings_helper.h

+1 −0
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
 * Sorted alphabetically.

 */



#include <linux/errname.h>

#include <linux/slab.h>

#include <linux/refcount.h>

#include <linux/wait.h>

rust/helpers.c

+7 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include <linux/bug.h>

#include <linux/build_bug.h>

#include <linux/err.h>

#include <linux/errname.h>

#include <linux/refcount.h>

#include <linux/mutex.h>

#include <linux/spinlock.h>
@@ -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;

rust/kernel/error.rs

+39 −0
Original line number Diff line number Diff line
@@ -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<AllocError> for Error {