diff options
Diffstat (limited to 'vendor/getrandom/src/error.rs')
| -rw-r--r-- | vendor/getrandom/src/error.rs | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/vendor/getrandom/src/error.rs b/vendor/getrandom/src/error.rs new file mode 100644 index 00000000..13f3121f --- /dev/null +++ b/vendor/getrandom/src/error.rs @@ -0,0 +1,212 @@ +#[cfg(feature = "std")] +extern crate std; + +use core::fmt; + +// This private alias mirrors `std::io::RawOsError`: +// https://doc.rust-lang.org/std/io/type.RawOsError.html) +cfg_if::cfg_if!( + if #[cfg(target_os = "uefi")] { + // See the UEFI spec for more information: + // https://uefi.org/specs/UEFI/2.10/Apx_D_Status_Codes.html + type RawOsError = usize; + type NonZeroRawOsError = core::num::NonZeroUsize; + const UEFI_ERROR_FLAG: RawOsError = 1 << (RawOsError::BITS - 1); + } else { + type RawOsError = i32; + type NonZeroRawOsError = core::num::NonZeroI32; + } +); + +/// A small and `no_std` compatible error type +/// +/// The [`Error::raw_os_error()`] will indicate if the error is from the OS, and +/// if so, which error code the OS gave the application. If such an error is +/// encountered, please consult with your system documentation. +/// +/// *If this crate's `"std"` Cargo feature is enabled*, then: +/// - [`getrandom::Error`][Error] implements +/// [`std::error::Error`](https://doc.rust-lang.org/std/error/trait.Error.html) +/// - [`std::io::Error`](https://doc.rust-lang.org/std/io/struct.Error.html) implements +/// [`From<getrandom::Error>`](https://doc.rust-lang.org/std/convert/trait.From.html). + +// note: on non-UEFI targets OS errors are represented as negative integers, +// while on UEFI targets OS errors have the highest bit set to 1. +#[derive(Copy, Clone, Eq, PartialEq)] +pub struct Error(NonZeroRawOsError); + +impl Error { + /// This target/platform is not supported by `getrandom`. + pub const UNSUPPORTED: Error = Self::new_internal(0); + /// The platform-specific `errno` returned a non-positive value. + pub const ERRNO_NOT_POSITIVE: Error = Self::new_internal(1); + /// Encountered an unexpected situation which should not happen in practice. + pub const UNEXPECTED: Error = Self::new_internal(2); + + /// Internal errors can be in the range of 2^16..2^17 + const INTERNAL_START: RawOsError = 1 << 16; + /// Custom errors can be in the range of 2^17..(2^17 + 2^16) + const CUSTOM_START: RawOsError = 1 << 17; + + /// Creates a new instance of an `Error` from a negative error code. + #[cfg(not(target_os = "uefi"))] + #[allow(dead_code)] + pub(super) fn from_neg_error_code(code: RawOsError) -> Self { + if code < 0 { + let code = NonZeroRawOsError::new(code).expect("`code` is negative"); + Self(code) + } else { + Error::UNEXPECTED + } + } + + /// Creates a new instance of an `Error` from an UEFI error code. + #[cfg(target_os = "uefi")] + #[allow(dead_code)] + pub(super) fn from_uefi_code(code: RawOsError) -> Self { + if code & UEFI_ERROR_FLAG != 0 { + let code = NonZeroRawOsError::new(code).expect("The highest bit of `code` is set to 1"); + Self(code) + } else { + Self::UNEXPECTED + } + } + + /// Extract the raw OS error code (if this error came from the OS) + /// + /// This method is identical to [`std::io::Error::raw_os_error()`][1], except + /// that it works in `no_std` contexts. On most targets this method returns + /// `Option<i32>`, but some platforms (e.g. UEFI) may use a different primitive + /// type like `usize`. Consult with the [`RawOsError`] docs for more information. + /// + /// If this method returns `None`, the error value can still be formatted via + /// the `Display` implementation. + /// + /// [1]: https://doc.rust-lang.org/std/io/struct.Error.html#method.raw_os_error + /// [`RawOsError`]: https://doc.rust-lang.org/std/io/type.RawOsError.html + #[inline] + pub fn raw_os_error(self) -> Option<RawOsError> { + let code = self.0.get(); + + // note: in this method we need to cover only backends which rely on + // `Error::{from_error_code, from_errno, from_uefi_code}` methods, + // on all other backends this method always returns `None`. + + #[cfg(target_os = "uefi")] + { + if code & UEFI_ERROR_FLAG != 0 { + Some(code) + } else { + None + } + } + + #[cfg(not(target_os = "uefi"))] + { + // On most targets `std` expects positive error codes while retrieving error strings: + // - `libc`-based targets use `strerror_r` which expects positive error codes. + // - Hermit relies on the `hermit-abi` crate, which expects positive error codes: + // https://docs.rs/hermit-abi/0.4.0/src/hermit_abi/errno.rs.html#400-532 + // - WASIp1 uses the same conventions as `libc`: + // https://github.com/rust-lang/rust/blob/1.85.0/library/std/src/sys/pal/wasi/os.rs#L57-L67 + // + // The only exception is Solid, `std` expects negative system error codes, see: + // https://github.com/rust-lang/rust/blob/1.85.0/library/std/src/sys/pal/solid/error.rs#L5-L31 + if code >= 0 { + None + } else if cfg!(not(target_os = "solid_asp3")) { + code.checked_neg() + } else { + Some(code) + } + } + } + + /// Creates a new instance of an `Error` from a particular custom error code. + pub const fn new_custom(n: u16) -> Error { + // SAFETY: code > 0 as CUSTOM_START > 0 and adding `n` won't overflow `RawOsError`. + let code = Error::CUSTOM_START + (n as RawOsError); + Error(unsafe { NonZeroRawOsError::new_unchecked(code) }) + } + + /// Creates a new instance of an `Error` from a particular internal error code. + pub(crate) const fn new_internal(n: u16) -> Error { + // SAFETY: code > 0 as INTERNAL_START > 0 and adding `n` won't overflow `RawOsError`. + let code = Error::INTERNAL_START + (n as RawOsError); + Error(unsafe { NonZeroRawOsError::new_unchecked(code) }) + } + + fn internal_desc(&self) -> Option<&'static str> { + let desc = match *self { + Error::UNSUPPORTED => "getrandom: this target is not supported", + Error::ERRNO_NOT_POSITIVE => "errno: did not return a positive value", + Error::UNEXPECTED => "unexpected situation", + #[cfg(any( + target_os = "ios", + target_os = "visionos", + target_os = "watchos", + target_os = "tvos", + ))] + Error::IOS_RANDOM_GEN => "SecRandomCopyBytes: iOS Security framework failure", + #[cfg(all(windows, target_vendor = "win7"))] + Error::WINDOWS_RTL_GEN_RANDOM => "RtlGenRandom: Windows system function failure", + #[cfg(all(feature = "wasm_js", getrandom_backend = "wasm_js"))] + Error::WEB_CRYPTO => "Web Crypto API is unavailable", + #[cfg(target_os = "vxworks")] + Error::VXWORKS_RAND_SECURE => "randSecure: VxWorks RNG module is not initialized", + + #[cfg(any( + getrandom_backend = "rdrand", + all(target_arch = "x86_64", target_env = "sgx") + ))] + Error::FAILED_RDRAND => "RDRAND: failed multiple times: CPU issue likely", + #[cfg(any( + getrandom_backend = "rdrand", + all(target_arch = "x86_64", target_env = "sgx") + ))] + Error::NO_RDRAND => "RDRAND: instruction not supported", + + #[cfg(getrandom_backend = "rndr")] + Error::RNDR_FAILURE => "RNDR: Could not generate a random number", + #[cfg(getrandom_backend = "rndr")] + Error::RNDR_NOT_AVAILABLE => "RNDR: Register not supported", + _ => return None, + }; + Some(desc) + } +} + +impl fmt::Debug for Error { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + let mut dbg = f.debug_struct("Error"); + if let Some(errno) = self.raw_os_error() { + dbg.field("os_error", &errno); + #[cfg(feature = "std")] + dbg.field("description", &std::io::Error::from_raw_os_error(errno)); + } else if let Some(desc) = self.internal_desc() { + dbg.field("internal_code", &self.0.get()); + dbg.field("description", &desc); + } else { + dbg.field("unknown_code", &self.0.get()); + } + dbg.finish() + } +} + +impl fmt::Display for Error { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + if let Some(errno) = self.raw_os_error() { + cfg_if! { + if #[cfg(feature = "std")] { + std::io::Error::from_raw_os_error(errno).fmt(f) + } else { + write!(f, "OS Error: {}", errno) + } + } + } else if let Some(desc) = self.internal_desc() { + f.write_str(desc) + } else { + write!(f, "Unknown Error: {}", self.0.get()) + } + } +} |
