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 78AD0288C2F; Mon, 7 Jul 2025 13:32:13 +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=1751895133; cv=none; b=PZvAvJtLBrY7oo6hcrPAZpMWWQZNygsmfMAXY2JkE9IVJGLJOVF3lqh8y/RjCfn+YtKtdhQKijfuTT1UKHF4YT8Fr0iqsOmLZJ9oD5GEFhbqKql+NVkX1XFg/5ECON89kjOJxQ/vWj9HL3Zc9Vio09rzgWnSOd/Web7zIF13zw4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751895133; c=relaxed/simple; bh=xTgqncA4NI+tPjWI9a96IMKRApYDZOqXCThKroirHhA=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=Cent2Xroh3boRpVWaJdYK/zGYYnNQXRBEwyk9TrC/EQOFUAEYq3zcJ3XYAB7nqWrWBXFCeqRwN97PhrCtMOJg7F94GADtTFzvixxQPHh2/U6ekdx//+Uy0RbVN0W9I/MRXs4a8hE+EiPY4KCScSWvAscl5g/3DmOIFBmLKutMSI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=sB+vnU69; 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="sB+vnU69" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 322E1C4CEE3; Mon, 7 Jul 2025 13:32:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1751895133; bh=xTgqncA4NI+tPjWI9a96IMKRApYDZOqXCThKroirHhA=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=sB+vnU69HxMSCkoRMbtYyBa6dLZFh4k/qfUsrorPPPOW39E4w4OTFbWm1WrAoOJAG Wi4dehWSoDjIMoE7+1Sn33Lb/KDxqvjxSYpNteE41hVNpF5HIr94Ux3FXW3WHZYZly xu1dDruoDVKcJH5ZUXD1uW5Qa9Yqb0afGsJ4A2vWPQEQKvyyiHUtBdZpsXvFAtgBxq mECS19F8lWEWP2LFVU2zinvGEC9z5Qozo5J6HuqX/Bei9xbv1eOVecdZYUcc2XS2kA NjeOdbreyK9+vve0wWtJhkHM2Gw6vEBlaik0gtDBmN61JwbxKq3wQRhaGXe7Bfxsku NA6i1UydIQ1PQ== From: Andreas Hindborg Date: Mon, 07 Jul 2025 15:29:06 +0200 Subject: [PATCH v15 2/7] rust: str: add radix prefixed integer parsing functions Precedence: bulk X-Mailing-List: rust-for-linux@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: <20250707-module-params-v3-v15-2-c1f4269a57b9@kernel.org> References: <20250707-module-params-v3-v15-0-c1f4269a57b9@kernel.org> In-Reply-To: <20250707-module-params-v3-v15-0-c1f4269a57b9@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=7157; i=a.hindborg@kernel.org; h=from:subject:message-id; bh=xTgqncA4NI+tPjWI9a96IMKRApYDZOqXCThKroirHhA=; b=owEBbQKS/ZANAwAIAeG4Gj55KGN3AcsmYgBoa8u0YVgXtBaiqfSOIzspRCuo+174uzFTZ5WLn /eP3pdkYraJAjMEAAEIAB0WIQQSwflHVr98KhXWwBLhuBo+eShjdwUCaGvLtAAKCRDhuBo+eShj d/65D/9+61la4COScehNwo31TfrUsfGY6NA49ubNGEENCBkOtrgWAxLVPaps+OrPL5YufVKi+9B uTVwWwz25flBGWKWxJOl2KSzCexs9jnrgZKE8UVhnQ89DQzUZBZry5I8wok5+FJrLABUNZwXV0l jkefzdwMOLIBi9NasWsbGbc8c7/1gZZIgz4hLSEQvA8yOKk63o6I8qdjeNXnp8GG3wcbP/1Qwr/ NXTcBZP9RuxKs6U+yjCmbAjRXr2Jze9L1tmZ0iziqQNpM+yf5q+mWocIBxaIyZ9R7+nE6kRJW3y MJfDYUOk/V3V85GmCEG3weA0yJDf2ADQfIBo0jQItUOVGtVc+u9SAtvuuFCveejqilupIXS/8SY VOf2Y2eTVA30kfZCvHkZePjTQBuME+6pbr26Qf0rQ8Onztg+szL+ZRUs9OVD0+sUIrYro2ruJai g+U2R1jzG+axmWGXsY6N2pBdY6HvMohdFDzWI8e1Bl77jRb2sFQcPJ2byP7PlIeIonlqsU2r9+5 3CeeI+aUGcxrH44G0umeSQ4MQisWsUx78a6Eb1ceP28y1tIyjpqVliqqm/UwzmSVZEmolHGw2cK YjGSsZr7yScxkPJggXM5VN/0Yiqvb0fxPMYN++x6uAt61wrC5Jx37lEpJCFA6K+OXSFtK+ptbtr Hz9UZgFzjdSC5dw== 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 Suggested-by: Benno Lossin Signed-off-by: Andreas Hindborg --- rust/kernel/str.rs | 2 + rust/kernel/str/parse_int.rs | 148 +++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 150 insertions(+) diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs index a927db8e079c3..2b6c8b4a0ae4b 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 0000000000000..48eb4c202984c --- /dev/null +++ b/rust/kernel/str/parse_int.rs @@ -0,0 +1,148 @@ +// 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::prelude::*; + use crate::str::BStr; + + /// Trait that allows parsing a [`&BStr`] to an integer with a radix. + pub trait FromStrRadix: Sized { + /// Parse `src` to [`Self`] using radix `radix`. + fn from_str_radix(src: &BStr, radix: u32) -> Result; + + /// Tries to convert `value` into [`Self`] and negates the resulting value. + fn from_u64_negated(value: u64) -> Result; + } +} + +/// 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)?; + Self::from_u64_negated(val) + } + _ => { + let (radix, digits) = strip_radix(src); + Self::from_str_radix(digits, radix).map_err(|_| EINVAL) + } + } + } +} + +macro_rules! impl_parse_int { + ($($ty:ty),*) => { + $( + impl private::FromStrRadix for $ty { + fn from_str_radix(src: &BStr, radix: u32) -> Result { + <$ty>::from_str_radix(core::str::from_utf8(src).map_err(|_| EINVAL)?, radix) + .map_err(|_| EINVAL) + } + + fn from_u64_negated(value: u64) -> Result { + const ABS_MIN: u64 = { + #[allow(unused_comparisons)] + if <$ty>::MIN < 0 { + 1u64 << (<$ty>::BITS - 1) + } else { + 0 + } + }; + + if value > ABS_MIN { + return Err(EINVAL); + } + + if value == ABS_MIN { + return Ok(<$ty>::MIN); + } + + // SAFETY: The above checks guarantee that `value` fits into `Self`: + // - if `Self` is unsigned, then `ABS_MIN == 0` and thus we have returned above + // (either `EINVAL` or `MIN`). + // - if `Self` is signed, then we have that `0 <= value < ABS_MIN`. And since + // `ABS_MIN - 1` fits into `Self` by construction, `value` also does. + let value: Self = unsafe { value.try_into().unwrap_unchecked() }; + + Ok((!value).wrapping_add(1)) + } + } + + impl ParseInt for $ty {} + )* + }; +} + +impl_parse_int![i8, u8, i16, u16, i32, u32, i64, u64, isize, usize]; -- 2.47.2