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 6EA5624678F; Thu, 12 Jun 2025 13:42:00 +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=1749735720; cv=none; b=ISewZUYEvjsaNQLHw8kUYNxeB73Erl9kQE+Vfe26g5uU2vu/3FfNiDDMZfxcffZVOlr7tyjalt1zTOYduDbXceeEuRtDJnlVXxZozUU0jA29TMBPVLHmNOopvIPsSDaqOhGctaCJ+5+/XeBGMAXpboPX1yQrKuyyyK8byhpYGso= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749735720; c=relaxed/simple; bh=1Zk5g4c16Y0HV+ODTr1tmXBR2FFrktQueKOUyeJhRoE=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=Bi4E2YydGLrcIDa6WicVCDbZ9MF5gX1+QoXqNP4pHK5fH31RqeR33qNqLJCG4OpxK1owyN6dA0mJVWsfdCiJFu0DoMhE6jYbwQ82GKQQkz6zqLJHBToJxmIX00pAnSez9o723MxDLRjzkHXvphS1AhlgQwrfsZ0/cZIPOKHPsjM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=AkQNwO45; 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="AkQNwO45" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 78DF5C4CEEA; Thu, 12 Jun 2025 13:41:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1749735720; bh=1Zk5g4c16Y0HV+ODTr1tmXBR2FFrktQueKOUyeJhRoE=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=AkQNwO45AjGclUDSyhcIjBeG0N+juuS207LArNb59QRcFmmgYp1Mf8uSYvlJlow/0 Q0lHeB5wVMdYliuNKAAp3lCN0fNC/klogrbwXYb2YuQhRNU41g97KdIDlGGwyrrWQH Ltsq2gu/1h1qyGnyQidznRAe/AxBftV6UCEYxtR+GOauKExtLcE2vGcDHCmnPtHGlk uttn4QlPg8gChCLHkIi/bL0jt0Zrl6T2tx0SEwiP1EHvPKJvR2kvV+D0ACMfZRoKQ2 WEddRxM3+3DuEmrVmdxdWz4efQnb0qoGrtEQ837H3fM9LYZ7x0xAjwZeIDXg+ezStN DBWUpFRS02IBQ== From: Andreas Hindborg Date: Thu, 12 Jun 2025 15:40:02 +0200 Subject: [PATCH v13 1/6] rust: str: add radix prefixed integer parsing functions Precedence: bulk X-Mailing-List: linux-kernel@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: <20250612-module-params-v3-v13-1-bc219cd1a3f8@kernel.org> References: <20250612-module-params-v3-v13-0-bc219cd1a3f8@kernel.org> In-Reply-To: <20250612-module-params-v3-v13-0-bc219cd1a3f8@kernel.org> To: Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Alice Ryhl , Masahiro Yamada , Nathan Chancellor , Luis Chamberlain , Danilo Krummrich , Benno Lossin , Benno Lossin , 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=7428; i=a.hindborg@kernel.org; h=from:subject:message-id; bh=1Zk5g4c16Y0HV+ODTr1tmXBR2FFrktQueKOUyeJhRoE=; b=owEBbQKS/ZANAwAIAeG4Gj55KGN3AcsmYgBoSti2h5MQjr8bdVGbxH+6TaWLZpN63COs78haP paQ8whrZ/yJAjMEAAEIAB0WIQQSwflHVr98KhXWwBLhuBo+eShjdwUCaErYtgAKCRDhuBo+eShj dwWFEACxCR5MqlEOysO50ToQYRiW/Fn4Zzh2S3FkmxKp7/dxGJ8/rNB9LLtsYJH32DzIQQpGl+v GG3ZzD6dnPQfZ1MefbBrxZYuFUqN+SN5qKXPK5kpg9c1APfIJAJ+wc/lGXh5YMYwtQ/L8TSR8/h Hv7gqbKd2RHGuJNQ36uHGm8cUB1hkWFWjPoJOqX0Qfls50Xvt0yhYLf8tdc7enEmzO83W6YI2YD FEypOh7/jNi3QMZQEYrjgZSheeOyDHKwcFMrV/usjVBJPQRVCndfjhINknMnDZqanWTrTgZVe3D lHENkgB023+CkR44R7P1yxHULZurGO2jfL8oHKQxEBVj64xbcbIXiUVDApI28R29/UQtltAOADQ jWT38noiM6TQjf5gfXkE+wg8MjCUhAiLQTWWNUwuNvdBd5OMDSQSA/JNgLIME14cX5MwH+yaAMv fjr0Va1Bn/6jCIP9Ih8Zs22LtLXam5GEM0RoLIA7mT2RoVEnshyrZg+K5Y2ESd6ugmlUPVGU1SF jz+MedZfAozt/WZaWu6Zv2M0eCcVUnAPEyGfSpIw3/52ebWDm7SbjHpM5h38de2COZUZzn6mIZ2 ou6SUGL+8RVB8pnmYztX8EZWrXdh94g25BOOXEXL3TWp914Ii9N7gWnSRcT0NQ8U7qzQqY6STqf 3/Z+4888pNa2G4g== 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 Gomez Reviewed-by: Greg Kroah-Hartman Signed-off-by: Andreas Hindborg --- rust/kernel/str.rs | 2 + rust/kernel/str/parse_int.rs | 171 +++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 173 insertions(+) diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs index a927db8e079c..2b6c8b4a0ae4 100644 --- a/rust/kernel/str.rs +++ b/rust/kernel/str.rs @@ -8,6 +8,8 @@ use crate::prelude::*; +pub mod parse_int; + /// Byte string without UTF-8 validity guarantee. #[repr(transparent)] pub struct BStr([u8]); diff --git a/rust/kernel/str/parse_int.rs b/rust/kernel/str/parse_int.rs new file mode 100644 index 000000000000..0754490aec4b --- /dev/null +++ b/rust/kernel/str/parse_int.rs @@ -0,0 +1,171 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Integer parsing functions. +//! +//! Integer parsing functions for parsing signed and unsigned integers +//! potentially prefixed with `0x`, `0o`, or `0b`. + +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