144 lines
4.4 KiB
Rust
144 lines
4.4 KiB
Rust
// SPDX-License-Identifier: GPL-2.0
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//! Kernel errors.
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//!
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//! C header: [`include/uapi/asm-generic/errno-base.h`](../../../include/uapi/asm-generic/errno-base.h)
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use alloc::{
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alloc::{AllocError, LayoutError},
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collections::TryReserveError,
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};
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use core::convert::From;
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use core::num::TryFromIntError;
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use core::str::Utf8Error;
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/// Contains the C-compatible error codes.
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pub mod code {
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macro_rules! declare_err {
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($err:tt $(,)? $($doc:expr),+) => {
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$(
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#[doc = $doc]
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)*
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pub const $err: super::Error = super::Error(-(crate::bindings::$err as i32));
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};
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}
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declare_err!(EPERM, "Operation not permitted.");
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declare_err!(ENOENT, "No such file or directory.");
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declare_err!(ESRCH, "No such process.");
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declare_err!(EINTR, "Interrupted system call.");
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declare_err!(EIO, "I/O error.");
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declare_err!(ENXIO, "No such device or address.");
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declare_err!(E2BIG, "Argument list too long.");
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declare_err!(ENOEXEC, "Exec format error.");
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declare_err!(EBADF, "Bad file number.");
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declare_err!(ECHILD, "Exec format error.");
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declare_err!(EAGAIN, "Try again.");
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declare_err!(ENOMEM, "Out of memory.");
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declare_err!(EACCES, "Permission denied.");
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declare_err!(EFAULT, "Bad address.");
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declare_err!(ENOTBLK, "Block device required.");
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declare_err!(EBUSY, "Device or resource busy.");
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declare_err!(EEXIST, "File exists.");
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declare_err!(EXDEV, "Cross-device link.");
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declare_err!(ENODEV, "No such device.");
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declare_err!(ENOTDIR, "Not a directory.");
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declare_err!(EISDIR, "Is a directory.");
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declare_err!(EINVAL, "Invalid argument.");
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declare_err!(ENFILE, "File table overflow.");
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declare_err!(EMFILE, "Too many open files.");
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declare_err!(ENOTTY, "Not a typewriter.");
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declare_err!(ETXTBSY, "Text file busy.");
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declare_err!(EFBIG, "File too large.");
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declare_err!(ENOSPC, "No space left on device.");
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declare_err!(ESPIPE, "Illegal seek.");
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declare_err!(EROFS, "Read-only file system.");
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declare_err!(EMLINK, "Too many links.");
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declare_err!(EPIPE, "Broken pipe.");
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declare_err!(EDOM, "Math argument out of domain of func.");
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declare_err!(ERANGE, "Math result not representable.");
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}
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/// Generic integer kernel error.
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///
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/// The kernel defines a set of integer generic error codes based on C and
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/// POSIX ones. These codes may have a more specific meaning in some contexts.
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///
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/// # Invariants
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///
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/// The value is a valid `errno` (i.e. `>= -MAX_ERRNO && < 0`).
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#[derive(Clone, Copy, PartialEq, Eq)]
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pub struct Error(core::ffi::c_int);
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impl Error {
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/// Returns the kernel error code.
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pub fn to_errno(self) -> core::ffi::c_int {
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self.0
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}
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}
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impl From<AllocError> for Error {
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fn from(_: AllocError) -> Error {
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code::ENOMEM
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}
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}
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impl From<TryFromIntError> for Error {
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fn from(_: TryFromIntError) -> Error {
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code::EINVAL
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}
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}
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impl From<Utf8Error> for Error {
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fn from(_: Utf8Error) -> Error {
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code::EINVAL
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}
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}
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impl From<TryReserveError> for Error {
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fn from(_: TryReserveError) -> Error {
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code::ENOMEM
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}
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}
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impl From<LayoutError> for Error {
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fn from(_: LayoutError) -> Error {
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code::ENOMEM
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}
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}
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impl From<core::fmt::Error> for Error {
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fn from(_: core::fmt::Error) -> Error {
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code::EINVAL
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}
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}
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impl From<core::convert::Infallible> for Error {
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fn from(e: core::convert::Infallible) -> Error {
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match e {}
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}
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}
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/// A [`Result`] with an [`Error`] error type.
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///
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/// To be used as the return type for functions that may fail.
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///
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/// # Error codes in C and Rust
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///
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/// In C, it is common that functions indicate success or failure through
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/// their return value; modifying or returning extra data through non-`const`
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/// pointer parameters. In particular, in the kernel, functions that may fail
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/// typically return an `int` that represents a generic error code. We model
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/// those as [`Error`].
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///
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/// In Rust, it is idiomatic to model functions that may fail as returning
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/// a [`Result`]. Since in the kernel many functions return an error code,
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/// [`Result`] is a type alias for a [`core::result::Result`] that uses
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/// [`Error`] as its error type.
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///
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/// Note that even if a function does not return anything when it succeeds,
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/// it should still be modeled as returning a `Result` rather than
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/// just an [`Error`].
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pub type Result<T = ()> = core::result::Result<T, Error>;
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