1 // SPDX-License-Identifier: GPL-2.0 2 3 //! Kernel errors. 4 //! 5 //! C header: [`include/uapi/asm-generic/errno-base.h`](../../../include/uapi/asm-generic/errno-base.h) 6 7 use alloc::collections::TryReserveError; 8 9 /// Contains the C-compatible error codes. 10 pub mod code { 11 macro_rules! declare_err { 12 ($err:tt $(,)? $($doc:expr),+) => { 13 $( 14 #[doc = $doc] 15 )* 16 pub const $err: super::Error = super::Error(-(crate::bindings::$err as i32)); 17 }; 18 } 19 20 declare_err!(EPERM, "Operation not permitted."); 21 declare_err!(ENOENT, "No such file or directory."); 22 declare_err!(ESRCH, "No such process."); 23 declare_err!(EINTR, "Interrupted system call."); 24 declare_err!(EIO, "I/O error."); 25 declare_err!(ENXIO, "No such device or address."); 26 declare_err!(E2BIG, "Argument list too long."); 27 declare_err!(ENOEXEC, "Exec format error."); 28 declare_err!(EBADF, "Bad file number."); 29 declare_err!(ECHILD, "Exec format error."); 30 declare_err!(EAGAIN, "Try again."); 31 declare_err!(ENOMEM, "Out of memory."); 32 declare_err!(EACCES, "Permission denied."); 33 declare_err!(EFAULT, "Bad address."); 34 declare_err!(ENOTBLK, "Block device required."); 35 declare_err!(EBUSY, "Device or resource busy."); 36 declare_err!(EEXIST, "File exists."); 37 declare_err!(EXDEV, "Cross-device link."); 38 declare_err!(ENODEV, "No such device."); 39 declare_err!(ENOTDIR, "Not a directory."); 40 declare_err!(EISDIR, "Is a directory."); 41 declare_err!(EINVAL, "Invalid argument."); 42 declare_err!(ENFILE, "File table overflow."); 43 declare_err!(EMFILE, "Too many open files."); 44 declare_err!(ENOTTY, "Not a typewriter."); 45 declare_err!(ETXTBSY, "Text file busy."); 46 declare_err!(EFBIG, "File too large."); 47 declare_err!(ENOSPC, "No space left on device."); 48 declare_err!(ESPIPE, "Illegal seek."); 49 declare_err!(EROFS, "Read-only file system."); 50 declare_err!(EMLINK, "Too many links."); 51 declare_err!(EPIPE, "Broken pipe."); 52 declare_err!(EDOM, "Math argument out of domain of func."); 53 declare_err!(ERANGE, "Math result not representable."); 54 } 55 56 /// Generic integer kernel error. 57 /// 58 /// The kernel defines a set of integer generic error codes based on C and 59 /// POSIX ones. These codes may have a more specific meaning in some contexts. 60 /// 61 /// # Invariants 62 /// 63 /// The value is a valid `errno` (i.e. `>= -MAX_ERRNO && < 0`). 64 #[derive(Clone, Copy, PartialEq, Eq)] 65 pub struct Error(core::ffi::c_int); 66 67 impl Error { 68 /// Returns the kernel error code. 69 pub fn to_kernel_errno(self) -> core::ffi::c_int { 70 self.0 71 } 72 } 73 74 impl From<TryReserveError> for Error { 75 fn from(_: TryReserveError) -> Error { 76 code::ENOMEM 77 } 78 } 79 80 /// A [`Result`] with an [`Error`] error type. 81 /// 82 /// To be used as the return type for functions that may fail. 83 /// 84 /// # Error codes in C and Rust 85 /// 86 /// In C, it is common that functions indicate success or failure through 87 /// their return value; modifying or returning extra data through non-`const` 88 /// pointer parameters. In particular, in the kernel, functions that may fail 89 /// typically return an `int` that represents a generic error code. We model 90 /// those as [`Error`]. 91 /// 92 /// In Rust, it is idiomatic to model functions that may fail as returning 93 /// a [`Result`]. Since in the kernel many functions return an error code, 94 /// [`Result`] is a type alias for a [`core::result::Result`] that uses 95 /// [`Error`] as its error type. 96 /// 97 /// Note that even if a function does not return anything when it succeeds, 98 /// it should still be modeled as returning a `Result` rather than 99 /// just an [`Error`]. 100 pub type Result<T = ()> = core::result::Result<T, Error>; 101