From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5DC9527C159; Thu, 1 May 2025 07:55:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746086111; cv=none; b=doaiJlER0shUUS7o2kTAl86Iq5Q+UBrL6BtDdyNmwBq963j5bBaE/4a2yGvcs+3n0hVPZFEeshb9QHM5Ug1BYGFScifUmkxV3hZbgt33hNvM8gJnpime5dBf6iw7yrXgx+TXsGw3ZU2lTdi8uQRZC5wm9LaTToxwnvhcqJkNtaY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746086111; c=relaxed/simple; bh=trB7rN8HIizFE195cRQop1qCgNg02JdXKC/J2wvL0+A=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=m01geN2psTBaUgCbjQcaMmEGSbvjmvVuIxT4L0u4TXdDuMNIpJ6thHMfy+BHEhhAbSYItmL2LsXAbpvW9p08/3MUvbZ19kA6RK/nR97od7QlOBW+zqFPwAniXr94zYaRTKDJwDO/Pm+p1517ZhYsh2bY5TY7qoV+9p2wc5hiN+I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=nTkXeYRV; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="nTkXeYRV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 35B5DC4CEE9; Thu, 1 May 2025 07:55:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1746086111; bh=trB7rN8HIizFE195cRQop1qCgNg02JdXKC/J2wvL0+A=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=nTkXeYRV1Kmh8bpMxSsor7Pf5mianBNMi++A0jcxnoGaqidESnt7098Y477y3Jm+V axM+p8d4/9zfMuvn+wM3QZfNG++N+EmheQwtFvEls5GdntdWv1g+N+dh28XMegNIlv Yz2yo9TnKob4QAMC3tBMOBA6ieGM6UWBmLyWnNt1XsaEeAPT3XNsy5OLGcEnxwAwFS FYLQYXOOCRf/FwXBlATw9sOhpyDI0k80eVqhyF6gljZ68PkN0pTDu6ULYVA3oDK2yi GCTZGEVpiH46llH+NDZDCUma844yJQ56BENIPAqyXdCr59kjtt3n8FNTy3kc2BL3T1 qopB+aJPJY/cg== From: Andreas Hindborg Date: Thu, 01 May 2025 09:53:37 +0200 Subject: [PATCH v10 1/3] rust: str: add radix prefixed integer parsing functions Precedence: bulk X-Mailing-List: linux-modules@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20250501-module-params-v3-v10-1-4da485d343d5@kernel.org> References: <20250501-module-params-v3-v10-0-4da485d343d5@kernel.org> In-Reply-To: <20250501-module-params-v3-v10-0-4da485d343d5@kernel.org> To: Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Alice Ryhl , Masahiro Yamada , Nathan Chancellor , Luis Chamberlain , Danilo Krummrich , Nicolas Schier Cc: Trevor Gross , Adam Bratschi-Kaye , rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, Petr Pavlu , Sami Tolvanen , Daniel Gomez , Simona Vetter , Greg KH , Fiona Behrens , Daniel Almeida , linux-modules@vger.kernel.org, Andreas Hindborg X-Mailer: b4 0.15-dev X-Developer-Signature: v=1; a=openpgp-sha256; l=7912; i=a.hindborg@kernel.org; h=from:subject:message-id; bh=trB7rN8HIizFE195cRQop1qCgNg02JdXKC/J2wvL0+A=; b=owEBbQKS/ZANAwAIAeG4Gj55KGN3AcsmYgBoEyidLtreCwhd4UB3vfqxCNrkpbXI3T+zlAo6R U8XxR+E7u6JAjMEAAEIAB0WIQQSwflHVr98KhXWwBLhuBo+eShjdwUCaBMonQAKCRDhuBo+eShj d5DVD/92cgyNOh56D33prXeGPbiTCY/bJrhNPrlkjwMDU68WI3TkN4zTHk80kftypliuyjrUZYP Trvlj/Z/GSlES8YMZicowELSXEge7R9uG2Wf2i4jI+bcrmgLlwW6YBLytsadGRULirMLCTs4j/Y +GdRgfXsxBLVWI7SlvR3ks264TPDaLYu66EDPKgC6123BhgMCwXVZDkPPBdLTu+NLOmoqYRAavA fqkis0W80cbdFLgSnDAobFn9dhdrbDnijLg2SEtADq03OlyMBwWnaBe7fjxb71K3cyKPIdYoG8v SrgjGPIoBfzFrkjmAxx/1KhQon85a9je0AGIu4or0SEqO4gA0Ym60QgYrxe9Nn4hUf1RwYFE07G E1vcFDYV09Rq841KOd9JpBnobuumAXGARBoQIg2aI4mHiitpeY6VRDcbxCB3+LjC5/vrzmK4Ucg QPi6sT7Xp1Zigwdr1v/VxITQMIKXAIAbENgOkxrdvYJzAf4Cb0NO49CM9JvYuX9BsQf5zrz25zu Jznzed8Ft2lnQrZC51ABtIObeUQjhvs2hFk3TbvuJrG52XoPMqzIdy3ZYgflyX96aNGv8PyC57p /gZfm1wu4EWLWRK/fJYoNiZlAqfymFkFy2Un2CMM942sjbCMIKq83bkPhIkqwd3ggB3L5U0l2Fc yEAoBTPp/HmqGKw== X-Developer-Key: i=a.hindborg@kernel.org; a=openpgp; fpr=3108C10F46872E248D1FB221376EB100563EF7A7 Add the trait `ParseInt` for parsing string representations of integers where the string representations are optionally prefixed by a radix specifier. Implement the trait for the primitive integer types. Tested-by: Daniel Almeida Reviewed-by: Daniel Almeida Signed-off-by: Andreas Hindborg --- rust/kernel/str.rs | 172 ++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 171 insertions(+), 1 deletion(-) diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs index 878111cb77bc..92ffabb8f939 100644 --- a/rust/kernel/str.rs +++ b/rust/kernel/str.rs @@ -573,7 +573,6 @@ macro_rules! c_str { } #[cfg(test)] -#[expect(clippy::items_after_test_module)] mod tests { use super::*; @@ -946,3 +945,174 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { macro_rules! fmt { ($($f:tt)*) => ( core::format_args!($($f)*) ) } + +/// Integer parsing functions for parsing signed and unsigned integers +/// potentially prefixed with `0x`, `0o`, or `0b`. +pub mod parse_int { + + use crate::prelude::*; + use crate::str::BStr; + use core::ops::Deref; + + // Make `FromStrRadix` a public type with a private name. This seals + // `ParseInt`, that is, prevents downstream users from implementing the + // trait. + mod private { + use crate::str::BStr; + + /// Trait that allows parsing a [`&BStr`] to an integer with a radix. + /// + /// # Safety + /// + /// The member functions of this trait must be implemented according to + /// their documentation. + /// + /// [`&BStr`]: kernel::str::BStr + // This is required because the `from_str_radix` function on the primitive + // integer types is not part of any trait. + pub unsafe trait FromStrRadix: Sized { + /// The minimum value this integer type can assume. + const MIN: Self; + + /// Parse `src` to [`Self`] using radix `radix`. + fn from_str_radix(src: &BStr, radix: u32) -> Result; + + /// Return the absolute value of [`Self::MIN`]. + fn abs_min() -> u64; + + /// Perform bitwise 2's complement on `self`. + /// + /// Note: This function does not make sense for unsigned integers. + fn complement(self) -> Self; + } + } + + /// Extract the radix from an integer literal optionally prefixed with + /// one of `0x`, `0X`, `0o`, `0O`, `0b`, `0B`, `0`. + fn strip_radix(src: &BStr) -> (u32, &BStr) { + match src.deref() { + [b'0', b'x' | b'X', rest @ ..] => (16, rest.as_ref()), + [b'0', b'o' | b'O', rest @ ..] => (8, rest.as_ref()), + [b'0', b'b' | b'B', rest @ ..] => (2, rest.as_ref()), + // NOTE: We are including the leading zero to be able to parse + // literal `0` here. If we removed it as a radix prefix, we would + // not be able to parse `0`. + [b'0', ..] => (8, src), + _ => (10, src), + } + } + + /// Trait for parsing string representations of integers. + /// + /// Strings beginning with `0x`, `0o`, or `0b` are parsed as hex, octal, or + /// binary respectively. Strings beginning with `0` otherwise are parsed as + /// octal. Anything else is parsed as decimal. A leading `+` or `-` is also + /// permitted. Any string parsed by [`kstrtol()`] or [`kstrtoul()`] will be + /// successfully parsed. + /// + /// [`kstrtol()`]: https://docs.kernel.org/core-api/kernel-api.html#c.kstrtol + /// [`kstrtoul()`]: https://docs.kernel.org/core-api/kernel-api.html#c.kstrtoul + /// + /// # Examples + /// ``` + /// # use kernel::str::parse_int::ParseInt; + /// # use kernel::b_str; + /// + /// assert_eq!(Ok(0u8), u8::from_str(b_str!("0"))); + /// + /// assert_eq!(Ok(0xa2u8), u8::from_str(b_str!("0xa2"))); + /// assert_eq!(Ok(-0xa2i32), i32::from_str(b_str!("-0xa2"))); + /// + /// assert_eq!(Ok(-0o57i8), i8::from_str(b_str!("-0o57"))); + /// assert_eq!(Ok(0o57i8), i8::from_str(b_str!("057"))); + /// + /// assert_eq!(Ok(0b1001i16), i16::from_str(b_str!("0b1001"))); + /// assert_eq!(Ok(-0b1001i16), i16::from_str(b_str!("-0b1001"))); + /// + /// assert_eq!(Ok(127i8), i8::from_str(b_str!("127"))); + /// assert!(i8::from_str(b_str!("128")).is_err()); + /// assert_eq!(Ok(-128i8), i8::from_str(b_str!("-128"))); + /// assert!(i8::from_str(b_str!("-129")).is_err()); + /// assert_eq!(Ok(255u8), u8::from_str(b_str!("255"))); + /// assert!(u8::from_str(b_str!("256")).is_err()); + /// ``` + pub trait ParseInt: private::FromStrRadix + TryFrom { + /// Parse a string according to the description in [`Self`]. + fn from_str(src: &BStr) -> Result { + match src.deref() { + [b'-', rest @ ..] => { + let (radix, digits) = strip_radix(rest.as_ref()); + // 2's complement values range from -2^(b-1) to 2^(b-1)-1. + // So if we want to parse negative numbers as positive and + // later multiply by -1, we have to parse into a larger + // integer. We choose u64 as sufficiently large. + // + // NOTE: 128 bit integers are not available on all + // platforms, hence the choice of 64 bits. + let val = u64::from_str_radix( + core::str::from_utf8(digits).map_err(|_| EINVAL)?, + radix, + ) + .map_err(|_| EINVAL)?; + + if val > Self::abs_min() { + return Err(EINVAL); + } + + if val == Self::abs_min() { + return Ok(Self::MIN); + } + + // SAFETY: We checked that `val` will fit in `Self` above. + let val: Self = unsafe { val.try_into().unwrap_unchecked() }; + + Ok(val.complement()) + } + _ => { + let (radix, digits) = strip_radix(src); + Self::from_str_radix(digits, radix).map_err(|_| EINVAL) + } + } + } + } + + macro_rules! impl_parse_int { + ($ty:ty) => { + // SAFETY: We implement the trait according to the documentation. + unsafe impl private::FromStrRadix for $ty { + const MIN: Self = <$ty>::MIN; + + fn from_str_radix(src: &BStr, radix: u32) -> Result { + <$ty>::from_str_radix(core::str::from_utf8(src).map_err(|_| EINVAL)?, radix) + .map_err(|_| EINVAL) + } + + fn abs_min() -> u64 { + #[allow(unused_comparisons)] + if Self::MIN < 0 { + 1u64 << (Self::BITS - 1) + } else { + 0 + } + } + + fn complement(self) -> Self { + (!self).wrapping_add((1 as $ty)) + } + } + + impl ParseInt for $ty {} + }; + } + + impl_parse_int!(i8); + impl_parse_int!(u8); + impl_parse_int!(i16); + impl_parse_int!(u16); + impl_parse_int!(i32); + impl_parse_int!(u32); + impl_parse_int!(i64); + impl_parse_int!(u64); + impl_parse_int!(isize); + impl_parse_int!(usize); +} -- 2.47.2