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Thu, 25 Sep 2025 06:42:59 -0700 (PDT) From: Tamir Duberstein Date: Thu, 25 Sep 2025 09:42:52 -0400 Subject: [PATCH v16 1/3] samples: rust: platform: remove trailing commas 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: quoted-printable Message-Id: <20250925-cstr-core-v16-1-5cdcb3470ec2@gmail.com> References: <20250925-cstr-core-v16-0-5cdcb3470ec2@gmail.com> In-Reply-To: <20250925-cstr-core-v16-0-5cdcb3470ec2@gmail.com> To: Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Greg Kroah-Hartman , "Rafael J. Wysocki" , Luis Chamberlain , Russ Weight , Peter Zijlstra , Ingo Molnar , Will Deacon , Waiman Long , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt , Christian Brauner , Alexander Viro , Jan Kara Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, linux-fsdevel@vger.kernel.org, Tamir Duberstein X-Mailer: b4 0.15-dev X-Developer-Signature: v=1; a=openssh-sha256; t=1758807776; l=1557; i=tamird@gmail.com; h=from:subject:message-id; bh=dR7SLmVNHIVh9rfgt0UBYbJhDHgMhtv5IQldU5Oo1x0=; b=U1NIU0lHAAAAAQAAADMAAAALc3NoLWVkMjU1MTkAAAAgtYz36g7iDMSkY5K7Ab51ksGX7hJgs MRt+XVZTrIzMVIAAAAGcGF0YXR0AAAAAAAAAAZzaGE1MTIAAABTAAAAC3NzaC1lZDI1NTE5AAAA QMBRuV/ubGHi6AJrHtMWEogs+gWnxrbm2zAAbtuo9cLcfxR+ZO72SsA4+aDO80NYB5ZrsYfMwz8 lhrWFoc//jAM= X-Developer-Key: i=tamird@gmail.com; a=openssh; fpr=SHA256:264rPmnnrb+ERkS7DDS3tuwqcJss/zevJRzoylqMsbc This prepares for the next commit in which we introduce a custom formatting macro; that macro doesn't handle these spurious commas, so just remove them. Signed-off-by: Tamir Duberstein Acked-by: Danilo Krummrich Reviewed-by: Benno Lossin --- samples/rust/rust_driver_platform.rs | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/samples/rust/rust_driver_platform.rs b/samples/rust/rust_drive= r_platform.rs index 69ed55b7b0fa..ad08df0d73f0 100644 --- a/samples/rust/rust_driver_platform.rs +++ b/samples/rust/rust_driver_platform.rs @@ -146,7 +146,7 @@ fn properties_parse(dev: &device::Device) -> Result { =20 let name =3D c_str!("test,u32-optional-prop"); let prop =3D fwnode.property_read::(name).or(0x12); - dev_info!(dev, "'{name}'=3D'{prop:#x}' (default =3D 0x12)\n",); + dev_info!(dev, "'{name}'=3D'{prop:#x}' (default =3D 0x12)\n"); =20 // A missing required property will print an error. Discard the er= ror to // prevent properties_parse from failing in that case. @@ -161,7 +161,7 @@ fn properties_parse(dev: &device::Device) -> Result { let prop: [i16; 4] =3D fwnode.property_read(name).required_by(dev)= ?; dev_info!(dev, "'{name}'=3D'{prop:?}'\n"); let len =3D fwnode.property_count_elem::(name)?; - dev_info!(dev, "'{name}' length is {len}\n",); + dev_info!(dev, "'{name}' length is {len}\n"); =20 let name =3D c_str!("test,i16-array"); let prop: KVec =3D fwnode.property_read_array_vec(name, 4)?.r= equired_by(dev)?; --=20 2.51.0 From nobody Thu Oct 2 00:49:15 2025 Received: from mail-qk1-f180.google.com (mail-qk1-f180.google.com [209.85.222.180]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D0E5327990D for ; Thu, 25 Sep 2025 13:43:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.222.180 ARC-Seal: i=1; a=rsa-sha256; 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Thu, 25 Sep 2025 06:43:03 -0700 (PDT) Received: from 137.1.168.192.in-addr.arpa ([2600:4808:6353:5c00:7c:b286:dba3:5ba8]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-800fa5f6dd7sm11852546d6.0.2025.09.25.06.43.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 25 Sep 2025 06:43:02 -0700 (PDT) From: Tamir Duberstein Date: Thu, 25 Sep 2025 09:42:53 -0400 Subject: [PATCH v16 2/3] rust: support formatting of foreign types 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: quoted-printable Message-Id: <20250925-cstr-core-v16-2-5cdcb3470ec2@gmail.com> References: <20250925-cstr-core-v16-0-5cdcb3470ec2@gmail.com> In-Reply-To: <20250925-cstr-core-v16-0-5cdcb3470ec2@gmail.com> To: Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Greg Kroah-Hartman , "Rafael J. Wysocki" , Luis Chamberlain , Russ Weight , Peter Zijlstra , Ingo Molnar , Will Deacon , Waiman Long , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt , Christian Brauner , Alexander Viro , Jan Kara Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, linux-fsdevel@vger.kernel.org, Tamir Duberstein X-Mailer: b4 0.15-dev X-Developer-Signature: v=1; a=openssh-sha256; t=1758807776; l=11126; i=tamird@gmail.com; h=from:subject:message-id; bh=56qk4oXZToDCRjUenEK2FztuuA7wWME8i0VRUMgg2i0=; b=U1NIU0lHAAAAAQAAADMAAAALc3NoLWVkMjU1MTkAAAAgtYz36g7iDMSkY5K7Ab51ksGX7hJgs MRt+XVZTrIzMVIAAAAGcGF0YXR0AAAAAAAAAAZzaGE1MTIAAABTAAAAC3NzaC1lZDI1NTE5AAAA QFS5FBG5hG6X0Xkek0CL7w9zjaW6ziGcSIXaI/fHnn4mWXQaWHA2ook+z/gflzaX3Y+2kzogSEE fyz6dlk+WKw8= X-Developer-Key: i=tamird@gmail.com; a=openssh; fpr=SHA256:264rPmnnrb+ERkS7DDS3tuwqcJss/zevJRzoylqMsbc Introduce a `fmt!` macro which wraps all arguments in `kernel::fmt::Adapter` and a `kernel::fmt::Display` trait. This enables formatting of foreign types (like `core::ffi::CStr`) that do not implement `core::fmt::Display` due to concerns around lossy conversions which do not apply in the kernel. Suggested-by: Alice Ryhl Link: https://rust-for-linux.zulipchat.com/#narrow/channel/288089-General/t= opic/Custom.20formatting/with/516476467 Acked-by: Greg Kroah-Hartman Reviewed-by: Alice Ryhl Acked-by: Danilo Krummrich Reviewed-by: Benno Lossin Signed-off-by: Tamir Duberstein --- rust/kernel/fmt.rs | 87 +++++++++++++++++++++++++++++++++++++++++++++- rust/kernel/prelude.rs | 3 +- rust/macros/fmt.rs | 94 ++++++++++++++++++++++++++++++++++++++++++++++= ++++ rust/macros/lib.rs | 19 ++++++++++ rust/macros/quote.rs | 7 ++++ 5 files changed, 207 insertions(+), 3 deletions(-) diff --git a/rust/kernel/fmt.rs b/rust/kernel/fmt.rs index 0306e8388968..84d634201d90 100644 --- a/rust/kernel/fmt.rs +++ b/rust/kernel/fmt.rs @@ -4,4 +4,89 @@ //! //! This module is intended to be used in place of `core::fmt` in kernel c= ode. =20 -pub use core::fmt::{Arguments, Debug, Display, Error, Formatter, Result, W= rite}; +pub use core::fmt::{Arguments, Debug, Error, Formatter, Result, Write}; + +/// Internal adapter used to route allow implementations of formatting tra= its for foreign types. +/// +/// It is inserted automatically by the [`fmt!`] macro and is not meant to= be used directly. +/// +/// [`fmt!`]: crate::prelude::fmt! +#[doc(hidden)] +pub struct Adapter(pub T); + +macro_rules! impl_fmt_adapter_forward { + ($($trait:ident),* $(,)?) =3D> { + $( + impl $trait for Adapter { + fn fmt(&self, f: &mut Formatter<'_>) -> Result { + let Self(t) =3D self; + $trait::fmt(t, f) + } + } + )* + }; +} + +use core::fmt::{Binary, LowerExp, LowerHex, Octal, Pointer, UpperExp, Uppe= rHex}; +impl_fmt_adapter_forward!(Debug, LowerHex, UpperHex, Octal, Binary, Pointe= r, LowerExp, UpperExp); + +/// A copy of [`core::fmt::Display`] that allows us to implement it for fo= reign types. +/// +/// Types should implement this trait rather than [`core::fmt::Display`]. = Together with the +/// [`Adapter`] type and [`fmt!`] macro, it allows for formatting foreign = types (e.g. types from +/// core) which do not implement [`core::fmt::Display`] directly. +/// +/// [`fmt!`]: crate::prelude::fmt! +pub trait Display { + /// Same as [`core::fmt::Display::fmt`]. + fn fmt(&self, f: &mut Formatter<'_>) -> Result; +} + +impl Display for &T { + fn fmt(&self, f: &mut Formatter<'_>) -> Result { + Display::fmt(*self, f) + } +} + +impl core::fmt::Display for Adapter<&T> { + fn fmt(&self, f: &mut Formatter<'_>) -> Result { + let Self(t) =3D self; + Display::fmt(t, f) + } +} + +macro_rules! impl_display_forward { + ($( + $( { $($generics:tt)* } )? $ty:ty $( { where $($where:tt)* } )? + ),* $(,)?) =3D> { + $( + impl$($($generics)*)? Display for $ty $(where $($where)*)? { + fn fmt(&self, f: &mut Formatter<'_>) -> Result { + core::fmt::Display::fmt(self, f) + } + } + )* + }; +} + +impl_display_forward!( + bool, + char, + core::panic::PanicInfo<'_>, + Arguments<'_>, + i128, + i16, + i32, + i64, + i8, + isize, + str, + u128, + u16, + u32, + u64, + u8, + usize, + {} crate::sync::Arc {where crate::sync::Arc: core::fm= t::Display}, + {} crate::sync::UniqueArc {where crate::sync::UniqueArc<= T>: core::fmt::Display}, +); diff --git a/rust/kernel/prelude.rs b/rust/kernel/prelude.rs index 198d09a31449..26424ad7e989 100644 --- a/rust/kernel/prelude.rs +++ b/rust/kernel/prelude.rs @@ -25,7 +25,7 @@ pub use crate::alloc::{flags::*, Box, KBox, KVBox, KVVec, KVec, VBox, VVec= , Vec}; =20 #[doc(no_inline)] -pub use macros::{export, kunit_tests, module, vtable}; +pub use macros::{export, fmt, kunit_tests, module, vtable}; =20 pub use pin_init::{init, pin_data, pin_init, pinned_drop, InPlaceWrite, In= it, PinInit, Zeroable}; =20 @@ -36,7 +36,6 @@ pub use super::dbg; pub use super::{dev_alert, dev_crit, dev_dbg, dev_emerg, dev_err, dev_info= , dev_notice, dev_warn}; pub use super::{pr_alert, pr_crit, pr_debug, pr_emerg, pr_err, pr_info, pr= _notice, pr_warn}; -pub use core::format_args as fmt; =20 pub use super::{try_init, try_pin_init}; =20 diff --git a/rust/macros/fmt.rs b/rust/macros/fmt.rs new file mode 100644 index 000000000000..2f4b9f6e2211 --- /dev/null +++ b/rust/macros/fmt.rs @@ -0,0 +1,94 @@ +// SPDX-License-Identifier: GPL-2.0 + +use proc_macro::{Ident, TokenStream, TokenTree}; +use std::collections::BTreeSet; + +/// Please see [`crate::fmt`] for documentation. +pub(crate) fn fmt(input: TokenStream) -> TokenStream { + let mut input =3D input.into_iter(); + + let first_opt =3D input.next(); + let first_owned_str; + let mut names =3D BTreeSet::new(); + let first_span =3D { + let Some((mut first_str, first_span)) =3D (match first_opt.as_ref(= ) { + Some(TokenTree::Literal(first_lit)) =3D> { + first_owned_str =3D first_lit.to_string(); + Some(first_owned_str.as_str()).and_then(|first| { + let first =3D first.strip_prefix('"')?; + let first =3D first.strip_suffix('"')?; + Some((first, first_lit.span())) + }) + } + _ =3D> None, + }) else { + return first_opt.into_iter().chain(input).collect(); + }; + + // Parse `identifier`s from the format string. + // + // See https://doc.rust-lang.org/std/fmt/index.html#syntax. + while let Some((_, rest)) =3D first_str.split_once('{') { + first_str =3D rest; + if let Some(rest) =3D first_str.strip_prefix('{') { + first_str =3D rest; + continue; + } + if let Some((name, rest)) =3D first_str.split_once('}') { + first_str =3D rest; + let name =3D name.split_once(':').map_or(name, |(name, _)|= name); + if !name.is_empty() && !name.chars().all(|c| c.is_ascii_di= git()) { + names.insert(name); + } + } + } + first_span + }; + + let adapter =3D quote_spanned!(first_span =3D> ::kernel::fmt::Adapter); + + let mut args =3D TokenStream::from_iter(first_opt); + { + let mut flush =3D |args: &mut TokenStream, current: &mut TokenStre= am| { + let current =3D std::mem::take(current); + if !current.is_empty() { + let (lhs, rhs) =3D (|| { + let mut current =3D current.into_iter(); + let mut acc =3D TokenStream::new(); + while let Some(tt) =3D current.next() { + // Split on `=3D` only once to handle cases like `= a =3D b =3D c`. + if matches!(&tt, TokenTree::Punct(p) if p.as_char(= ) =3D=3D '=3D') { + names.remove(acc.to_string().as_str()); + // Include the `=3D` itself to keep the handli= ng below uniform. + acc.extend([tt]); + return (Some(acc), current.collect::()); + } + acc.extend([tt]); + } + (None, acc) + })(); + args.extend(quote_spanned!(first_span =3D> #lhs #adapter(&= #rhs))); + } + }; + + let mut current =3D TokenStream::new(); + for tt in input { + match &tt { + TokenTree::Punct(p) if p.as_char() =3D=3D ',' =3D> { + flush(&mut args, &mut current); + &mut args + } + _ =3D> &mut current, + } + .extend([tt]); + } + flush(&mut args, &mut current); + } + + for name in names { + let name =3D Ident::new(name, first_span); + args.extend(quote_spanned!(first_span =3D> , #name =3D #adapter(&#= name))); + } + + quote_spanned!(first_span =3D> ::core::format_args!(#args)) +} diff --git a/rust/macros/lib.rs b/rust/macros/lib.rs index fa847cf3a9b5..793f712dbf7c 100644 --- a/rust/macros/lib.rs +++ b/rust/macros/lib.rs @@ -15,6 +15,7 @@ mod quote; mod concat_idents; mod export; +mod fmt; mod helpers; mod kunit; mod module; @@ -201,6 +202,24 @@ pub fn export(attr: TokenStream, ts: TokenStream) -> T= okenStream { export::export(attr, ts) } =20 +/// Like [`core::format_args!`], but automatically wraps arguments in [`ke= rnel::fmt::Adapter`]. +/// +/// This macro allows generating `fmt::Arguments` while ensuring that each= argument is wrapped with +/// `::kernel::fmt::Adapter`, which customizes formatting behavior for ker= nel logging. +/// +/// Named arguments used in the format string (e.g. `{foo}`) are detected = and resolved from local +/// bindings. All positional and named arguments are automatically wrapped. +/// +/// This macro is an implementation detail of other kernel logging macros = like [`pr_info!`] and +/// should not typically be used directly. +/// +/// [`kernel::fmt::Adapter`]: ../kernel/fmt/struct.Adapter.html +/// [`pr_info!`]: ../kernel/macro.pr_info.html +#[proc_macro] +pub fn fmt(input: TokenStream) -> TokenStream { + fmt::fmt(input) +} + /// Concatenate two identifiers. /// /// This is useful in macros that need to declare or reference items with = names diff --git a/rust/macros/quote.rs b/rust/macros/quote.rs index acc140c18653..ddfc21577539 100644 --- a/rust/macros/quote.rs +++ b/rust/macros/quote.rs @@ -48,6 +48,7 @@ macro_rules! quote_spanned { ($span:expr =3D> $($tt:tt)*) =3D> {{ let mut tokens =3D ::proc_macro::TokenStream::new(); { + #[allow(unused_variables)] let span =3D $span; quote_spanned!(@proc tokens span $($tt)*); } @@ -146,6 +147,12 @@ macro_rules! quote_spanned { )]); quote_spanned!(@proc $v $span $($tt)*); 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Thu, 25 Sep 2025 06:43:05 -0700 (PDT) Received: from 137.1.168.192.in-addr.arpa ([2600:4808:6353:5c00:7c:b286:dba3:5ba8]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-800fa5f6dd7sm11852546d6.0.2025.09.25.06.43.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 25 Sep 2025 06:43:04 -0700 (PDT) From: Tamir Duberstein Date: Thu, 25 Sep 2025 09:42:54 -0400 Subject: [PATCH v16 3/3] rust: replace `CStr` with `core::ffi::CStr` 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: quoted-printable Message-Id: <20250925-cstr-core-v16-3-5cdcb3470ec2@gmail.com> References: <20250925-cstr-core-v16-0-5cdcb3470ec2@gmail.com> In-Reply-To: <20250925-cstr-core-v16-0-5cdcb3470ec2@gmail.com> To: Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Greg Kroah-Hartman , "Rafael J. Wysocki" , Luis Chamberlain , Russ Weight , Peter Zijlstra , Ingo Molnar , Will Deacon , Waiman Long , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt , Christian Brauner , Alexander Viro , Jan Kara Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, linux-fsdevel@vger.kernel.org, Tamir Duberstein X-Mailer: b4 0.15-dev X-Developer-Signature: v=1; a=openssh-sha256; t=1758807776; l=25735; i=tamird@gmail.com; h=from:subject:message-id; bh=lo6/DuevQdN2F/RgLUH3cR/iIKA6DNW579sKIqtC5y0=; b=U1NIU0lHAAAAAQAAADMAAAALc3NoLWVkMjU1MTkAAAAgtYz36g7iDMSkY5K7Ab51ksGX7hJgs MRt+XVZTrIzMVIAAAAGcGF0YXR0AAAAAAAAAAZzaGE1MTIAAABTAAAAC3NzaC1lZDI1NTE5AAAA QGOSVgbfQFgBBK1sTKXw49unThqPQREAQTbAwpwCMInDQ5kk/6iWOOdUZq57ZhyITIc8O/CMyTJ +lx4GYTjkJAE= X-Developer-Key: i=tamird@gmail.com; a=openssh; fpr=SHA256:264rPmnnrb+ERkS7DDS3tuwqcJss/zevJRzoylqMsbc `kernel::ffi::CStr` was introduced in commit d126d2380131 ("rust: str: add `CStr` type") in November 2022 as an upstreaming of earlier work that was done in May 2021[0]. That earlier work, having predated the inclusion of `CStr` in `core`, largely duplicated the implementation of `std::ffi::CStr`. `std::ffi::CStr` was moved to `core::ffi::CStr` in Rust 1.64 in September 2022. Hence replace `kernel::str::CStr` with `core::ffi::CStr` to reduce our custom code footprint, and retain needed custom functionality through an extension trait. Add `CStr` to `ffi` and the kernel prelude. Link: https://github.com/Rust-for-Linux/linux/commit/faa3cbcca03d0dec8f8e43= f1d8d5c0860d98a23f [0] Acked-by: Greg Kroah-Hartman Reviewed-by: Alice Ryhl Acked-by: Danilo Krummrich Reviewed-by: Benno Lossin Signed-off-by: Tamir Duberstein --- rust/ffi.rs | 2 + rust/kernel/device.rs | 1 + rust/kernel/error.rs | 2 + rust/kernel/firmware.rs | 9 +- rust/kernel/prelude.rs | 4 +- rust/kernel/seq_file.rs | 2 +- rust/kernel/str.rs | 395 +++++++++---------------------------= ---- rust/kernel/sync/condvar.rs | 2 +- rust/kernel/sync/lock.rs | 2 +- rust/kernel/sync/lock/global.rs | 2 +- 10 files changed, 109 insertions(+), 312 deletions(-) diff --git a/rust/ffi.rs b/rust/ffi.rs index d60aad792af4..f961e9728f59 100644 --- a/rust/ffi.rs +++ b/rust/ffi.rs @@ -46,3 +46,5 @@ macro_rules! alias { } =20 pub use core::ffi::c_void; + +pub use core::ffi::CStr; diff --git a/rust/kernel/device.rs b/rust/kernel/device.rs index 303af0ef9bf7..f3718da11871 100644 --- a/rust/kernel/device.rs +++ b/rust/kernel/device.rs @@ -12,6 +12,7 @@ =20 #[cfg(CONFIG_PRINTK)] use crate::c_str; +use crate::str::CStrExt as _; =20 pub mod property; =20 diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs index 1c0e0e241daa..258b12afdcba 100644 --- a/rust/kernel/error.rs +++ b/rust/kernel/error.rs @@ -182,6 +182,8 @@ pub fn name(&self) -> Option<&'static CStr> { if ptr.is_null() { None } else { + use crate::str::CStrExt as _; + // SAFETY: The string returned by `errname` is static and `NUL= `-terminated. Some(unsafe { CStr::from_char_ptr(ptr) }) } diff --git a/rust/kernel/firmware.rs b/rust/kernel/firmware.rs index 94e6bb88b903..376e7e77453f 100644 --- a/rust/kernel/firmware.rs +++ b/rust/kernel/firmware.rs @@ -4,7 +4,14 @@ //! //! C header: [`include/linux/firmware.h`](srctree/include/linux/firmware.= h) =20 -use crate::{bindings, device::Device, error::Error, error::Result, ffi, st= r::CStr}; +use crate::{ + bindings, + device::Device, + error::Error, + error::Result, + ffi, + str::{CStr, CStrExt as _}, +}; use core::ptr::NonNull; =20 /// # Invariants diff --git a/rust/kernel/prelude.rs b/rust/kernel/prelude.rs index 26424ad7e989..33fa8404c5c6 100644 --- a/rust/kernel/prelude.rs +++ b/rust/kernel/prelude.rs @@ -19,7 +19,7 @@ =20 pub use ::ffi::{ c_char, c_int, c_long, c_longlong, c_schar, c_short, c_uchar, c_uint, = c_ulong, c_ulonglong, - c_ushort, c_void, + c_ushort, c_void, CStr, }; =20 pub use crate::alloc::{flags::*, Box, KBox, KVBox, KVVec, KVec, VBox, VVec= , Vec}; @@ -43,7 +43,7 @@ =20 pub use super::error::{code::*, Error, Result}; =20 -pub use super::{str::CStr, ThisModule}; +pub use super::{str::CStrExt as _, ThisModule}; =20 pub use super::init::InPlaceInit; =20 diff --git a/rust/kernel/seq_file.rs b/rust/kernel/seq_file.rs index 59fbfc2473f8..855e533813a6 100644 --- a/rust/kernel/seq_file.rs +++ b/rust/kernel/seq_file.rs @@ -4,7 +4,7 @@ //! //! C header: [`include/linux/seq_file.h`](srctree/include/linux/seq_file.= h) =20 -use crate::{bindings, c_str, fmt, types::NotThreadSafe, types::Opaque}; +use crate::{bindings, c_str, fmt, str::CStrExt as _, types::NotThreadSafe,= types::Opaque}; =20 /// A utility for generating the contents of a seq file. #[repr(transparent)] diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs index 6c892550c0ba..624386cb07be 100644 --- a/rust/kernel/str.rs +++ b/rust/kernel/str.rs @@ -4,10 +4,12 @@ =20 use crate::alloc::{flags::*, AllocError, KVec}; use crate::fmt::{self, Write}; -use core::ops::{self, Deref, DerefMut, Index}; +use core::ops::{Deref, DerefMut, Index}; =20 use crate::prelude::*; =20 +pub use crate::prelude::CStr; + /// Byte string without UTF-8 validity guarantee. #[repr(transparent)] pub struct BStr([u8]); @@ -181,58 +183,17 @@ macro_rules! b_str { // - error[E0379]: functions in trait impls cannot be declared const #[inline] pub const fn as_char_ptr_in_const_context(c_str: &CStr) -> *const c_char { - c_str.0.as_ptr() + c_str.as_ptr().cast() } =20 -/// Possible errors when using conversion functions in [`CStr`]. -#[derive(Debug, Clone, Copy)] -pub enum CStrConvertError { - /// Supplied bytes contain an interior `NUL`. - InteriorNul, - - /// Supplied bytes are not terminated by `NUL`. - NotNulTerminated, -} +mod private { + pub trait Sealed {} =20 -impl From for Error { - #[inline] - fn from(_: CStrConvertError) -> Error { - EINVAL - } + impl Sealed for super::CStr {} } =20 -/// A string that is guaranteed to have exactly one `NUL` byte, which is a= t the -/// end. -/// -/// Used for interoperability with kernel APIs that take C strings. -#[repr(transparent)] -pub struct CStr([u8]); - -impl CStr { - /// Returns the length of this string excluding `NUL`. - #[inline] - pub const fn len(&self) -> usize { - self.len_with_nul() - 1 - } - - /// Returns the length of this string with `NUL`. - #[inline] - pub const fn len_with_nul(&self) -> usize { - if self.0.is_empty() { - // SAFETY: This is one of the invariant of `CStr`. - // We add a `unreachable_unchecked` here to hint the optimizer= that - // the value returned from this function is non-zero. - unsafe { core::hint::unreachable_unchecked() }; - } - self.0.len() - } - - /// Returns `true` if the string only includes `NUL`. - #[inline] - pub const fn is_empty(&self) -> bool { - self.len() =3D=3D 0 - } - +/// Extensions to [`CStr`]. +pub trait CStrExt: private::Sealed { /// Wraps a raw C string pointer. /// /// # Safety @@ -240,54 +201,9 @@ pub const fn is_empty(&self) -> bool { /// `ptr` must be a valid pointer to a `NUL`-terminated C string, and = it must /// last at least `'a`. When `CStr` is alive, the memory pointed by `p= tr` /// must not be mutated. - #[inline] - pub unsafe fn from_char_ptr<'a>(ptr: *const c_char) -> &'a Self { - // SAFETY: The safety precondition guarantees `ptr` is a valid poi= nter - // to a `NUL`-terminated C string. - let len =3D unsafe { bindings::strlen(ptr) } + 1; - // SAFETY: Lifetime guaranteed by the safety precondition. - let bytes =3D unsafe { core::slice::from_raw_parts(ptr.cast(), len= ) }; - // SAFETY: As `len` is returned by `strlen`, `bytes` does not cont= ain interior `NUL`. - // As we have added 1 to `len`, the last byte is known to be `NUL`. - unsafe { Self::from_bytes_with_nul_unchecked(bytes) } - } - - /// Creates a [`CStr`] from a `[u8]`. - /// - /// The provided slice must be `NUL`-terminated, does not contain any - /// interior `NUL` bytes. - pub const fn from_bytes_with_nul(bytes: &[u8]) -> Result<&Self, CStrCo= nvertError> { - if bytes.is_empty() { - return Err(CStrConvertError::NotNulTerminated); - } - if bytes[bytes.len() - 1] !=3D 0 { - return Err(CStrConvertError::NotNulTerminated); - } - let mut i =3D 0; - // `i + 1 < bytes.len()` allows LLVM to optimize away bounds check= ing, - // while it couldn't optimize away bounds checks for `i < bytes.le= n() - 1`. - while i + 1 < bytes.len() { - if bytes[i] =3D=3D 0 { - return Err(CStrConvertError::InteriorNul); - } - i +=3D 1; - } - // SAFETY: We just checked that all properties hold. - Ok(unsafe { Self::from_bytes_with_nul_unchecked(bytes) }) - } - - /// Creates a [`CStr`] from a `[u8]` without performing any additional - /// checks. - /// - /// # Safety - /// - /// `bytes` *must* end with a `NUL` byte, and should only have a single - /// `NUL` byte (or the string will be truncated). - #[inline] - pub const unsafe fn from_bytes_with_nul_unchecked(bytes: &[u8]) -> &CS= tr { - // SAFETY: Properties of `bytes` guaranteed by the safety precondi= tion. - unsafe { core::mem::transmute(bytes) } - } + // This function exists to paper over the fact that `CStr::from_ptr` t= akes a `*const + // core::ffi::c_char` rather than a `*const crate::ffi::c_char`. + unsafe fn from_char_ptr<'a>(ptr: *const c_char) -> &'a Self; =20 /// Creates a mutable [`CStr`] from a `[u8]` without performing any /// additional checks. @@ -296,99 +212,16 @@ pub const fn from_bytes_with_nul(bytes: &[u8]) -> Res= ult<&Self, CStrConvertError /// /// `bytes` *must* end with a `NUL` byte, and should only have a single /// `NUL` byte (or the string will be truncated). - #[inline] - pub unsafe fn from_bytes_with_nul_unchecked_mut(bytes: &mut [u8]) -> &= mut CStr { - // SAFETY: Properties of `bytes` guaranteed by the safety precondi= tion. - unsafe { &mut *(core::ptr::from_mut(bytes) as *mut CStr) } - } + unsafe fn from_bytes_with_nul_unchecked_mut(bytes: &mut [u8]) -> &mut = Self; =20 /// Returns a C pointer to the string. - /// - /// Using this function in a const context is deprecated in favor of - /// [`as_char_ptr_in_const_context`] in preparation for replacing `CSt= r` with `core::ffi::CStr` - /// which does not have this method. - #[inline] - pub const fn as_char_ptr(&self) -> *const c_char { - as_char_ptr_in_const_context(self) - } - - /// Convert the string to a byte slice without the trailing `NUL` byte. - #[inline] - pub fn to_bytes(&self) -> &[u8] { - &self.0[..self.len()] - } - - /// Convert the string to a byte slice without the trailing `NUL` byte. - /// - /// This function is deprecated in favor of [`Self::to_bytes`] in prep= aration for replacing - /// `CStr` with `core::ffi::CStr` which does not have this method. - #[inline] - pub fn as_bytes(&self) -> &[u8] { - self.to_bytes() - } - - /// Convert the string to a byte slice containing the trailing `NUL` b= yte. - #[inline] - pub const fn to_bytes_with_nul(&self) -> &[u8] { - &self.0 - } - - /// Convert the string to a byte slice containing the trailing `NUL` b= yte. - /// - /// This function is deprecated in favor of [`Self::to_bytes_with_nul`= ] in preparation for - /// replacing `CStr` with `core::ffi::CStr` which does not have this m= ethod. - #[inline] - pub const fn as_bytes_with_nul(&self) -> &[u8] { - self.to_bytes_with_nul() - } - - /// Yields a [`&str`] slice if the [`CStr`] contains valid UTF-8. - /// - /// If the contents of the [`CStr`] are valid UTF-8 data, this - /// function will return the corresponding [`&str`] slice. Otherwise, - /// it will return an error with details of where UTF-8 validation fai= led. - /// - /// # Examples - /// - /// ``` - /// # use kernel::str::CStr; - /// let cstr =3D CStr::from_bytes_with_nul(b"foo\0")?; - /// assert_eq!(cstr.to_str(), Ok("foo")); - /// # Ok::<(), kernel::error::Error>(()) - /// ``` - #[inline] - pub fn to_str(&self) -> Result<&str, core::str::Utf8Error> { - core::str::from_utf8(self.as_bytes()) - } - - /// Unsafely convert this [`CStr`] into a [`&str`], without checking f= or - /// valid UTF-8. - /// - /// # Safety - /// - /// The contents must be valid UTF-8. - /// - /// # Examples - /// - /// ``` - /// # use kernel::c_str; - /// # use kernel::str::CStr; - /// let bar =3D c_str!("=E3=83=84"); - /// // SAFETY: String literals are guaranteed to be valid UTF-8 - /// // by the Rust compiler. - /// assert_eq!(unsafe { bar.as_str_unchecked() }, "=E3=83=84"); - /// ``` - #[inline] - pub unsafe fn as_str_unchecked(&self) -> &str { - // SAFETY: TODO. - unsafe { core::str::from_utf8_unchecked(self.as_bytes()) } - } + // This function exists to paper over the fact that `CStr::as_ptr` ret= urns a `*const + // core::ffi::c_char` rather than a `*const crate::ffi::c_char`. + fn as_char_ptr(&self) -> *const c_char; =20 /// Convert this [`CStr`] into a [`CString`] by allocating memory and /// copying over the string data. - pub fn to_cstring(&self) -> Result { - CString::try_from(self) - } + fn to_cstring(&self) -> Result; =20 /// Converts this [`CStr`] to its ASCII lower case equivalent in-place. /// @@ -399,11 +232,7 @@ pub fn to_cstring(&self) -> Result { /// [`to_ascii_lowercase()`]. /// /// [`to_ascii_lowercase()`]: #method.to_ascii_lowercase - pub fn make_ascii_lowercase(&mut self) { - // INVARIANT: This doesn't introduce or remove NUL bytes in the C - // string. - self.0.make_ascii_lowercase(); - } + fn make_ascii_lowercase(&mut self); =20 /// Converts this [`CStr`] to its ASCII upper case equivalent in-place. /// @@ -414,11 +243,7 @@ pub fn make_ascii_lowercase(&mut self) { /// [`to_ascii_uppercase()`]. /// /// [`to_ascii_uppercase()`]: #method.to_ascii_uppercase - pub fn make_ascii_uppercase(&mut self) { - // INVARIANT: This doesn't introduce or remove NUL bytes in the C - // string. - self.0.make_ascii_uppercase(); - } + fn make_ascii_uppercase(&mut self); =20 /// Returns a copy of this [`CString`] where each character is mapped = to its /// ASCII lower case equivalent. @@ -429,13 +254,7 @@ pub fn make_ascii_uppercase(&mut self) { /// To lowercase the value in-place, use [`make_ascii_lowercase`]. /// /// [`make_ascii_lowercase`]: str::make_ascii_lowercase - pub fn to_ascii_lowercase(&self) -> Result { - let mut s =3D self.to_cstring()?; - - s.make_ascii_lowercase(); - - Ok(s) - } + fn to_ascii_lowercase(&self) -> Result; =20 /// Returns a copy of this [`CString`] where each character is mapped = to its /// ASCII upper case equivalent. @@ -446,13 +265,7 @@ pub fn to_ascii_lowercase(&self) -> Result { /// To uppercase the value in-place, use [`make_ascii_uppercase`]. /// /// [`make_ascii_uppercase`]: str::make_ascii_uppercase - pub fn to_ascii_uppercase(&self) -> Result { - let mut s =3D self.to_cstring()?; - - s.make_ascii_uppercase(); - - Ok(s) - } + fn to_ascii_uppercase(&self) -> Result; } =20 impl fmt::Display for CStr { @@ -485,98 +298,75 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Res= ult { } } =20 -impl fmt::Debug for CStr { - /// Formats printable ASCII characters with a double quote on either e= nd, escaping the rest. - /// - /// ``` - /// # use kernel::c_str; - /// # use kernel::prelude::fmt; - /// # use kernel::str::CStr; - /// # use kernel::str::CString; - /// let penguin =3D c_str!("=F0=9F=90=A7"); - /// let s =3D CString::try_from_fmt(fmt!("{penguin:?}"))?; - /// assert_eq!(s.as_bytes_with_nul(), "\"\\xf0\\x9f\\x90\\xa7\"\0".as_= bytes()); - /// - /// // Embedded double quotes are escaped. - /// let ascii =3D c_str!("so \"cool\""); - /// let s =3D CString::try_from_fmt(fmt!("{ascii:?}"))?; - /// assert_eq!(s.as_bytes_with_nul(), "\"so \\\"cool\\\"\"\0".as_bytes= ()); - /// # Ok::<(), kernel::error::Error>(()) - /// ``` - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.write_str("\"")?; - for &c in self.as_bytes() { - match c { - // Printable characters. - b'\"' =3D> f.write_str("\\\"")?, - 0x20..=3D0x7e =3D> f.write_char(c as char)?, - _ =3D> write!(f, "\\x{c:02x}")?, - } - } - f.write_str("\"") - } +/// Converts a mutable C string to a mutable byte slice. +/// +/// # Safety +/// +/// The caller must ensure that the slice ends in a NUL byte and contains = no other NUL bytes before +/// the borrow ends and the underlying [`CStr`] is used. +unsafe fn to_bytes_mut(s: &mut CStr) -> &mut [u8] { + // SAFETY: the cast from `&CStr` to `&[u8]` is safe since `CStr` has t= he same layout as `&[u8]` + // (this is technically not guaranteed, but we rely on it here). The p= ointer dereference is + // safe since it comes from a mutable reference which is guaranteed to= be valid for writes. + unsafe { &mut *(core::ptr::from_mut(s) as *mut [u8]) } } =20 -impl AsRef for CStr { +impl CStrExt for CStr { #[inline] - fn as_ref(&self) -> &BStr { - BStr::from_bytes(self.as_bytes()) + unsafe fn from_char_ptr<'a>(ptr: *const c_char) -> &'a Self { + // SAFETY: The safety preconditions are the same as for `CStr::fro= m_ptr`. + unsafe { CStr::from_ptr(ptr.cast()) } } -} =20 -impl Deref for CStr { - type Target =3D BStr; + #[inline] + unsafe fn from_bytes_with_nul_unchecked_mut(bytes: &mut [u8]) -> &mut = Self { + // SAFETY: the cast from `&[u8]` to `&CStr` is safe since the prop= erties of `bytes` are + // guaranteed by the safety precondition and `CStr` has the same l= ayout as `&[u8]` (this is + // technically not guaranteed, but we rely on it here). The pointe= r dereference is safe + // since it comes from a mutable reference which is guaranteed to = be valid for writes. + unsafe { &mut *(core::ptr::from_mut(bytes) as *mut CStr) } + } =20 #[inline] - fn deref(&self) -> &Self::Target { - self.as_ref() + fn as_char_ptr(&self) -> *const c_char { + self.as_ptr().cast() + } + + fn to_cstring(&self) -> Result { + CString::try_from(self) } -} =20 -impl Index> for CStr { - type Output =3D CStr; + fn make_ascii_lowercase(&mut self) { + // SAFETY: This doesn't introduce or remove NUL bytes in the C str= ing. + unsafe { to_bytes_mut(self) }.make_ascii_lowercase(); + } =20 - #[inline] - fn index(&self, index: ops::RangeFrom) -> &Self::Output { - // Delegate bounds checking to slice. - // Assign to _ to mute clippy's unnecessary operation warning. - let _ =3D &self.as_bytes()[index.start..]; - // SAFETY: We just checked the bounds. - unsafe { Self::from_bytes_with_nul_unchecked(&self.0[index.start..= ]) } + fn make_ascii_uppercase(&mut self) { + // SAFETY: This doesn't introduce or remove NUL bytes in the C str= ing. + unsafe { to_bytes_mut(self) }.make_ascii_uppercase(); } -} =20 -impl Index for CStr { - type Output =3D CStr; + fn to_ascii_lowercase(&self) -> Result { + let mut s =3D self.to_cstring()?; =20 - #[inline] - fn index(&self, _index: ops::RangeFull) -> &Self::Output { - self + s.make_ascii_lowercase(); + + Ok(s) } -} =20 -mod private { - use core::ops; + fn to_ascii_uppercase(&self) -> Result { + let mut s =3D self.to_cstring()?; =20 - // Marker trait for index types that can be forward to `BStr`. - pub trait CStrIndex {} + s.make_ascii_uppercase(); =20 - impl CStrIndex for usize {} - impl CStrIndex for ops::Range {} - impl CStrIndex for ops::RangeInclusive {} - impl CStrIndex for ops::RangeToInclusive {} + Ok(s) + } } =20 -impl Index for CStr -where - Idx: private::CStrIndex, - BStr: Index, -{ - type Output =3D >::Output; - +impl AsRef for CStr { #[inline] - fn index(&self, index: Idx) -> &Self::Output { - &self.as_ref()[index] + fn as_ref(&self) -> &BStr { + BStr::from_bytes(self.to_bytes()) } } =20 @@ -607,6 +397,13 @@ macro_rules! c_str { mod tests { use super::*; =20 + impl From for Error { + #[inline] + fn from(_: core::ffi::FromBytesWithNulError) -> Error { + EINVAL + } + } + macro_rules! format { ($($f:tt)*) =3D> ({ CString::try_from_fmt(fmt!($($f)*))?.to_str()? @@ -629,40 +426,28 @@ macro_rules! format { =20 #[test] fn test_cstr_to_str() -> Result { - let good_bytes =3D b"\xf0\x9f\xa6\x80\0"; - let checked_cstr =3D CStr::from_bytes_with_nul(good_bytes)?; - let checked_str =3D checked_cstr.to_str()?; + let cstr =3D c"\xf0\x9f\xa6\x80"; + let checked_str =3D cstr.to_str()?; assert_eq!(checked_str, "=F0=9F=A6=80"); Ok(()) } =20 #[test] fn test_cstr_to_str_invalid_utf8() -> Result { - let bad_bytes =3D b"\xc3\x28\0"; - let checked_cstr =3D CStr::from_bytes_with_nul(bad_bytes)?; - assert!(checked_cstr.to_str().is_err()); - Ok(()) - } - - #[test] - fn test_cstr_as_str_unchecked() -> Result { - let good_bytes =3D b"\xf0\x9f\x90\xA7\0"; - let checked_cstr =3D CStr::from_bytes_with_nul(good_bytes)?; - // SAFETY: The contents come from a string literal which contains = valid UTF-8. - let unchecked_str =3D unsafe { checked_cstr.as_str_unchecked() }; - assert_eq!(unchecked_str, "=F0=9F=90=A7"); + let cstr =3D c"\xc3\x28"; + assert!(cstr.to_str().is_err()); Ok(()) } =20 #[test] fn test_cstr_display() -> Result { - let hello_world =3D CStr::from_bytes_with_nul(b"hello, world!\0")?; + let hello_world =3D c"hello, world!"; assert_eq!(format!("{hello_world}"), "hello, world!"); - let non_printables =3D CStr::from_bytes_with_nul(b"\x01\x09\x0a\0"= )?; + let non_printables =3D c"\x01\x09\x0a"; assert_eq!(format!("{non_printables}"), "\\x01\\x09\\x0a"); - let non_ascii =3D CStr::from_bytes_with_nul(b"d\xe9j\xe0 vu\0")?; + let non_ascii =3D c"d\xe9j\xe0 vu"; assert_eq!(format!("{non_ascii}"), "d\\xe9j\\xe0 vu"); - let good_bytes =3D CStr::from_bytes_with_nul(b"\xf0\x9f\xa6\x80\0"= )?; + let good_bytes =3D c"\xf0\x9f\xa6\x80"; assert_eq!(format!("{good_bytes}"), "\\xf0\\x9f\\xa6\\x80"); Ok(()) } @@ -681,13 +466,13 @@ fn test_cstr_display_all_bytes() -> Result { =20 #[test] fn test_cstr_debug() -> Result { - let hello_world =3D CStr::from_bytes_with_nul(b"hello, world!\0")?; + let hello_world =3D c"hello, world!"; assert_eq!(format!("{hello_world:?}"), "\"hello, world!\""); - let non_printables =3D CStr::from_bytes_with_nul(b"\x01\x09\x0a\0"= )?; - assert_eq!(format!("{non_printables:?}"), "\"\\x01\\x09\\x0a\""); - let non_ascii =3D CStr::from_bytes_with_nul(b"d\xe9j\xe0 vu\0")?; + let non_printables =3D c"\x01\x09\x0a"; + assert_eq!(format!("{non_printables:?}"), "\"\\x01\\t\\n\""); + let non_ascii =3D c"d\xe9j\xe0 vu"; assert_eq!(format!("{non_ascii:?}"), "\"d\\xe9j\\xe0 vu\""); - let good_bytes =3D CStr::from_bytes_with_nul(b"\xf0\x9f\xa6\x80\0"= )?; + let good_bytes =3D c"\xf0\x9f\xa6\x80"; assert_eq!(format!("{good_bytes:?}"), "\"\\xf0\\x9f\\xa6\\x80\""); Ok(()) } diff --git a/rust/kernel/sync/condvar.rs b/rust/kernel/sync/condvar.rs index c6ec64295c9f..a24e25a690ee 100644 --- a/rust/kernel/sync/condvar.rs +++ b/rust/kernel/sync/condvar.rs @@ -8,7 +8,7 @@ use super::{lock::Backend, lock::Guard, LockClassKey}; use crate::{ ffi::{c_int, c_long}, - str::CStr, + str::{CStr, CStrExt as _}, task::{ MAX_SCHEDULE_TIMEOUT, TASK_FREEZABLE, TASK_INTERRUPTIBLE, TASK_NOR= MAL, TASK_UNINTERRUPTIBLE, }, diff --git a/rust/kernel/sync/lock.rs b/rust/kernel/sync/lock.rs index 27202beef90c..5d7991e6d373 100644 --- a/rust/kernel/sync/lock.rs +++ b/rust/kernel/sync/lock.rs @@ -7,7 +7,7 @@ =20 use super::LockClassKey; use crate::{ - str::CStr, + str::{CStr, CStrExt as _}, types::{NotThreadSafe, Opaque, ScopeGuard}, }; use core::{cell::UnsafeCell, marker::PhantomPinned, pin::Pin}; diff --git a/rust/kernel/sync/lock/global.rs b/rust/kernel/sync/lock/global= .rs index d65f94b5caf2..79d0ef7fda86 100644 --- a/rust/kernel/sync/lock/global.rs +++ b/rust/kernel/sync/lock/global.rs @@ -5,7 +5,7 @@ //! Support for defining statics containing locks. =20 use crate::{ - str::CStr, + str::{CStr, CStrExt as _}, sync::lock::{Backend, Guard, Lock}, sync::{LockClassKey, LockedBy}, types::Opaque, --=20 2.51.0