From patchwork Fri Mar 21 09:17:34 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andreas Hindborg X-Patchwork-Id: 14025051 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 90A0F1F03F4; Fri, 21 Mar 2025 09:18:36 +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=1742548716; cv=none; b=Y6Fx0kfjezFtdL1NM8tKIFHB9EbI/D//VX6JKrItb7DCJENHU3ZHdVX+c7mEMB/odjIgDre2KlsybQDSVuIY7WedkJdOuimV8a2OPn6k1aC9esvk9bwOp1f31gzYUGXV8B7PanYogxtOKNen2FmDT7mldTAFbmeAXK8COkmy6Ag= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742548716; c=relaxed/simple; bh=sCW19nzrlwKLY8toSkWFitagnE2dtqdJ0NHcRxGxCRI=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=QwNCENlMfltzzgoCGvNbzK6bTRerO3xasKhhuMTv8CgljUeZHqtLquXyqgycENPuufStdvAogC6Kmn2kiufz0LFcKHayV/MulTHz1v3aZvY4hbOvf6G4AMOyHwzZL+HHbv5MOWD4n+WH7LWUj9Po7gWOSzedYJpg1jcTDQ4RK8M= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=MvshrXsL; 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="MvshrXsL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 27C2EC4CEE3; Fri, 21 Mar 2025 09:18:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1742548716; bh=sCW19nzrlwKLY8toSkWFitagnE2dtqdJ0NHcRxGxCRI=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=MvshrXsL5J8yEJ6pLRK7lWXDlQpuRiiBUfEKw4ftMP12zVD5aP5yTHdij+MAWeWP1 SQ0N4F4eCYkX8E8JlyVe/XERcI4k7Nw692OHblCm3ua3tXQluCBY8eIbeSrBuRjTiU cdrX+8bSpELqMTCXrKg5fYoK77dnko4LpMvE1BKhe2Ad2FljnBJY/ezHA3KzGUs1ZO blcZwsJYfoPKcnbiS2Rd9H+zjOKD5z0uevhP0VimV5+GHcwf8sboFzWaHY1qRL5Nrp w2lGWomBA1aBSoUSl85GcuTzgi4inPAUw798dLjobgj8E/VABmdT9/+HMjbybPNI5E p38DMWXPVmxmw== From: Andreas Hindborg Date: Fri, 21 Mar 2025 10:17:34 +0100 Subject: [PATCH v9 1/3] rust: str: add radix prefixed integer parsing functions Precedence: bulk X-Mailing-List: linux-kbuild@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20250321-module-params-v3-v9-1-28b905f2e345@kernel.org> References: <20250321-module-params-v3-v9-0-28b905f2e345@kernel.org> In-Reply-To: <20250321-module-params-v3-v9-0-28b905f2e345@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 , Nicolas Schier , Luis Chamberlain , Danilo Krummrich 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=7742; i=a.hindborg@kernel.org; h=from:subject:message-id; bh=sCW19nzrlwKLY8toSkWFitagnE2dtqdJ0NHcRxGxCRI=; b=owEBbQKS/ZANAwAIAeG4Gj55KGN3AcsmYgBn3S7DDzfCvCVd1geFru40zNvER27+CDGh87Rid 8ZQ8d4kCZeJAjMEAAEIAB0WIQQSwflHVr98KhXWwBLhuBo+eShjdwUCZ90uwwAKCRDhuBo+eShj dzx5EAC4aQCfDTDnt/kSlqXQSLzCwxWqffOGemTbhdAQ8ny5H/SLSl5olD7LU4utIz19/0aQolP yBcT7cZj4rmxPddHlSH8DCxJus8SmEvlLRelVEzqlYhk64ZZYzSRc1a6Msov0juWXiOxinuq00O 26MkNAqdHwqWi6uZ7Q7stqkTakvEe83oxnsJesTvA0BWhm5oRoabdCI4LSwX26hDYRSeXQJq88A 3WoDVLE1mLBX/TaRmWi/FqQKIDMIDg08j36OpkUYQkj8ryZuGL5A9I2qThmfd3F1FynN1eVsIBN dg+Mz0HkrqJppgNjEFu2irsfCPDqdu5O/NeQQgVc/6bAf19tAo3oT/8FSIhRnzusht1XX+EpVJM 9z/HVyoArLZB2J9fgwN/eM6AO/HDeMrUHz220HpOJ9E9gniHJP8VFmbAv9V2DqJPX2QqSFPbZ+p zY88MW1MHl92XKGWa9tN5NquDBHjn99e9jGjpJR2sZXAK9CveVewsAQY1tBiuQAkWhXD5DT3kLe l15DKHBpmbEoU1X888SsMP4r770aYODREUyJmm3+5T1BE1Yr3MB7PLllfFWAvzK8CnwMx6A09+C NUhD+/V7q4xFfpok6L4KmIJSmeV48xFcqBKC9easniXE2nmH7E1XADg8WfL2mEPHAoF1RgTdLFW BQTS6Xw7Eo/sEOg== 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 | 170 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 170 insertions(+) diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs index 878111cb77bc..0bfa2c1cf942 100644 --- a/rust/kernel/str.rs +++ b/rust/kernel/str.rs @@ -946,3 +946,173 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { macro_rules! fmt { ($($f:tt)*) => ( core::format_args!($($f)*) ) } + +pub mod parse_int { + //! 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://www.kernel.org/doc/html/latest/core-api/kernel-api.html#c.kstrtol + /// [`kstrtoul()`]: https://www.kernel.org/doc/html/latest/core-api/kernel-api.html#c.kstrtoul + /// + /// # Example + /// ``` + /// use kernel::str::parse_int::ParseInt; + /// use kernel::b_str; + /// + /// assert_eq!(Ok(0), 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(127), i8::from_str(b_str!("127"))); + /// assert!(i8::from_str(b_str!("128")).is_err()); + /// assert_eq!(Ok(-128), i8::from_str(b_str!("-128"))); + /// assert!(i8::from_str(b_str!("-129")).is_err()); + /// assert_eq!(Ok(255), 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 bit. + 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); +}