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.

Replace all direct calls to `format_args!` with `fmt!`.

Replace all implementations of `core::fmt::Display` with implementations of `kernel::fmt::Display`.

Suggested-by: Alice Ryhl aliceryhl@google.com Link: https://rust-for-linux.zulipchat.com/#narrow/channel/288089-General/topic/Cu... Acked-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Reviewed-by: Alice Ryhl aliceryhl@google.com Signed-off-by: Tamir Duberstein tamird@gmail.com --- drivers/block/rnull.rs | 2 +- drivers/gpu/nova-core/gpu.rs | 4 +- rust/kernel/block/mq.rs | 2 +- rust/kernel/device.rs | 2 +- rust/kernel/fmt.rs | 89 +++++++++++++++++++++++++++++++++++++++ rust/kernel/kunit.rs | 6 +-- rust/kernel/lib.rs | 1 + rust/kernel/prelude.rs | 3 +- rust/kernel/print.rs | 4 +- rust/kernel/seq_file.rs | 2 +- rust/kernel/str.rs | 22 ++++------ rust/macros/fmt.rs | 99 ++++++++++++++++++++++++++++++++++++++++++++ rust/macros/lib.rs | 19 +++++++++ rust/macros/quote.rs | 7 ++++ scripts/rustdoc_test_gen.rs | 2 +- 15 files changed, 236 insertions(+), 28 deletions(-)

diff --git a/drivers/block/rnull.rs b/drivers/block/rnull.rs index d07e76ae2c13..6366da12c5a5 100644 --- a/drivers/block/rnull.rs +++ b/drivers/block/rnull.rs @@ -51,7 +51,7 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> { .logical_block_size(4096)? .physical_block_size(4096)? .rotational(false) - .build(format_args!("rnullb{}", 0), tagset) + .build(fmt!("rnullb{}", 0), tagset) })();

try_pin_init!(Self { diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs index 60b86f370284..e6b208175ff9 100644 --- a/drivers/gpu/nova-core/gpu.rs +++ b/drivers/gpu/nova-core/gpu.rs @@ -91,7 +91,7 @@ pub(crate) fn arch(&self) -> Architecture { // Hence, replace with something like strum_macros derive(Display). // // For now, redirect to fmt::Debug for convenience. -impl fmt::Display for Chipset { +impl kernel::fmt::Display for Chipset { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { write!(f, "{self:?}") } @@ -132,7 +132,7 @@ fn from_boot0(boot0: regs::NV_PMC_BOOT_0) -> Self { } }

-impl fmt::Display for Revision { +impl kernel::fmt::Display for Revision { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { write!(f, "{:x}.{:x}", self.major, self.minor) } diff --git a/rust/kernel/block/mq.rs b/rust/kernel/block/mq.rs index 831445d37181..61ea35bba7d5 100644 --- a/rust/kernel/block/mq.rs +++ b/rust/kernel/block/mq.rs @@ -82,7 +82,7 @@ //! Arc::pin_init(TagSet::new(1, 256, 1), flags::GFP_KERNEL)?; //! let mut disk = gen_disk::GenDiskBuilder::new() //! .capacity_sectors(4096) -//! .build(format_args!("myblk"), tagset)?; +//! .build(fmt!("myblk"), tagset)?; //! //! # Ok::<(), kernel::error::Error>(()) //! ``` diff --git a/rust/kernel/device.rs b/rust/kernel/device.rs index 5c946af3a4d5..86b945576780 100644 --- a/rust/kernel/device.rs +++ b/rust/kernel/device.rs @@ -345,7 +345,7 @@ macro_rules! impl_device_context_into_aref { macro_rules! dev_printk { ($method:ident, $dev:expr, $($f:tt)*) => { { - ($dev).$method(::core::format_args!($($f)*)); + ($dev).$method($crate::prelude::fmt!($($f)*)); } } } diff --git a/rust/kernel/fmt.rs b/rust/kernel/fmt.rs new file mode 100644 index 000000000000..348d16987de6 --- /dev/null +++ b/rust/kernel/fmt.rs @@ -0,0 +1,89 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Formatting utilities. + +use core::fmt; + +/// Internal adapter used to route allow implementations of formatting traits for foreign types. +/// +/// It is inserted automatically by the [`fmt!`] macro and is not meant to be used directly. +/// +/// [`fmt!`]: crate::prelude::fmt! +#[doc(hidden)] +pub struct Adapter<T>(pub T); + +macro_rules! impl_fmt_adapter_forward { + ($($trait:ident),* $(,)?) => { + $( + impl<T: fmt::$trait> fmt::$trait for Adapter<T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + let Self(t) = self; + fmt::$trait::fmt(t, f) + } + } + )* + }; +} + +impl_fmt_adapter_forward!(Debug, LowerHex, UpperHex, Octal, Binary, Pointer, LowerExp, UpperExp); + +/// A copy of [`fmt::Display`] that allows us to implement it for foreign types. +/// +/// Types should implement this trait rather than [`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 [`fmt::Display`] directly. +/// +/// [`fmt!`]: crate::prelude::fmt! +pub trait Display { + /// Same as [`fmt::Display::fmt`]. + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result; +} + +impl<T: ?Sized + Display> Display for &T { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + Display::fmt(*self, f) + } +} + +impl<T: ?Sized + Display> fmt::Display for Adapter<&T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + let Self(t) = self; + Display::fmt(t, f) + } +} + +macro_rules! impl_display_forward { + ($( + $( { $($generics:tt)* } )? $ty:ty $( { where $($where:tt)* } )? + ),* $(,)?) => { + $( + impl$($($generics)*)? Display for $ty $(where $($where)*)? { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + fmt::Display::fmt(self, f) + } + } + )* + }; +} + +impl_display_forward!( + bool, + char, + core::panic::PanicInfo<'_>, + fmt::Arguments<'_>, + i128, + i16, + i32, + i64, + i8, + isize, + str, + u128, + u16, + u32, + u64, + u8, + usize, + {<T: ?Sized>} crate::sync::Arc<T> {where crate::sync::Arc<T>: fmt::Display}, + {<T: ?Sized>} crate::sync::UniqueArc<T> {where crate::sync::UniqueArc<T>: fmt::Display}, +); diff --git a/rust/kernel/kunit.rs b/rust/kernel/kunit.rs index 099a61bbb8f4..3539edbceaf5 100644 --- a/rust/kernel/kunit.rs +++ b/rust/kernel/kunit.rs @@ -74,14 +74,14 @@ macro_rules! kunit_assert { // mistake (it is hidden to prevent that). // // This mimics KUnit's failed assertion format. - $crate::kunit::err(format_args!( + $crate::kunit::err($crate::prelude::fmt!( " # {}: ASSERTION FAILED at {FILE}:{LINE}\n", $name )); - $crate::kunit::err(format_args!( + $crate::kunit::err($crate::prelude::fmt!( " Expected {CONDITION} to be true, but is false\n" )); - $crate::kunit::err(format_args!( + $crate::kunit::err($crate::prelude::fmt!( " Failure not reported to KUnit since this is a non-KUnit task\n" )); break 'out; diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index 6b4774b2b1c3..aadcfaa5c759 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -77,6 +77,7 @@ pub mod faux; #[cfg(CONFIG_RUST_FW_LOADER_ABSTRACTIONS)] pub mod firmware; +pub mod fmt; pub mod fs; pub mod init; pub mod io; diff --git a/rust/kernel/prelude.rs b/rust/kernel/prelude.rs index 2f30a398dddd..41cebd906c4c 100644 --- a/rust/kernel/prelude.rs +++ b/rust/kernel/prelude.rs @@ -22,7 +22,7 @@ pub use crate::alloc::{flags::*, Box, KBox, KVBox, KVVec, KVec, VBox, VVec, Vec};

#[doc(no_inline)] -pub use macros::{export, kunit_tests, module, vtable}; +pub use macros::{export, fmt, kunit_tests, module, vtable};

pub use pin_init::{init, pin_data, pin_init, pinned_drop, InPlaceWrite, Init, PinInit, Zeroable};

@@ -31,7 +31,6 @@ // `super::std_vendor` is hidden, which makes the macro inline for some reason. #[doc(no_inline)] pub use super::dbg; -pub use super::fmt; 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};

diff --git a/rust/kernel/print.rs b/rust/kernel/print.rs index ecdcee43e5a5..d9c619edcd2f 100644 --- a/rust/kernel/print.rs +++ b/rust/kernel/print.rs @@ -149,7 +149,7 @@ macro_rules! print_macro ( // takes borrows on the arguments, but does not extend the scope of temporaries. // Therefore, a `match` expression is used to keep them around, since // the scrutinee is kept until the end of the `match`. - match format_args!($($arg)+) { + match $crate::prelude::fmt!($($arg)+) { // SAFETY: This hidden macro should only be called by the documented // printing macros which ensure the format string is one of the fixed // ones. All `__LOG_PREFIX`s are null-terminated as they are generated @@ -168,7 +168,7 @@ macro_rules! print_macro ( // The `CONT` case. ($format_string:path, true, $($arg:tt)+) => ( $crate::print::call_printk_cont( - format_args!($($arg)+), + $crate::prelude::fmt!($($arg)+), ); ); ); diff --git a/rust/kernel/seq_file.rs b/rust/kernel/seq_file.rs index 8f199b1a3bb1..05c9b7bec727 100644 --- a/rust/kernel/seq_file.rs +++ b/rust/kernel/seq_file.rs @@ -47,7 +47,7 @@ pub fn call_printf(&self, args: core::fmt::Arguments<'_>) { #[macro_export] macro_rules! seq_print { ($m:expr, $($arg:tt)+) => ( - $m.call_printf(format_args!($($arg)+)) + $m.call_printf($crate::prelude::fmt!($($arg)+)) ); } pub use seq_print; diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs index cbc8b459ed41..d3fa4b703d35 100644 --- a/rust/kernel/str.rs +++ b/rust/kernel/str.rs @@ -50,11 +50,11 @@ pub fn strip_prefix(&self, pattern: impl AsRef<Self>) -> Option<&BStr> { } }

-impl fmt::Display for BStr { +impl crate::fmt::Display for BStr { /// Formats printable ASCII characters, escaping the rest. /// /// ``` - /// # use kernel::{fmt, b_str, str::{BStr, CString}}; + /// # use kernel::{prelude::fmt, b_str, str::{BStr, CString}}; /// let ascii = b_str!("Hello, BStr!"); /// let s = CString::try_from_fmt(fmt!("{}", ascii))?; /// assert_eq!(s.as_bytes(), "Hello, BStr!".as_bytes()); @@ -85,7 +85,7 @@ impl fmt::Debug for BStr { /// escaping the rest. /// /// ``` - /// # use kernel::{fmt, b_str, str::{BStr, CString}}; + /// # use kernel::{prelude::fmt, b_str, str::{BStr, CString}}; /// // Embedded double quotes are escaped. /// let ascii = b_str!("Hello, "BStr"!"); /// let s = CString::try_from_fmt(fmt!("{:?}", ascii))?; @@ -424,12 +424,12 @@ pub fn to_ascii_uppercase(&self) -> Result<CString, AllocError> { } }

-impl fmt::Display for CStr { +impl crate::fmt::Display for CStr { /// Formats printable ASCII characters, escaping the rest. /// /// ``` /// # use kernel::c_str; - /// # use kernel::fmt; + /// # use kernel::prelude::fmt; /// # use kernel::str::CStr; /// # use kernel::str::CString; /// let penguin = c_str!("🐧"); @@ -459,7 +459,7 @@ impl fmt::Debug for CStr { /// /// ``` /// # use kernel::c_str; - /// # use kernel::fmt; + /// # use kernel::prelude::fmt; /// # use kernel::str::CStr; /// # use kernel::str::CString; /// let penguin = c_str!("🐧"); @@ -578,7 +578,7 @@ mod tests {

macro_rules! format { ($($f:tt)*) => ({ - CString::try_from_fmt(::kernel::fmt!($($f)*))?.to_str()? + CString::try_from_fmt(crate::prelude::fmt!($($f)*))?.to_str()? }) }

@@ -840,7 +840,7 @@ fn write_str(&mut self, s: &str) -> fmt::Result { /// # Examples /// /// ``` -/// use kernel::{str::CString, fmt}; +/// use kernel::{str::CString, prelude::fmt}; /// /// let s = CString::try_from_fmt(fmt!("{}{}{}", "abc", 10, 20))?; /// assert_eq!(s.as_bytes_with_nul(), "abc1020\0".as_bytes()); @@ -930,9 +930,3 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { fmt::Debug::fmt(&**self, f) } } - -/// A convenience alias for [`core::format_args`]. -#[macro_export] -macro_rules! fmt { - ($($f:tt)*) => ( ::core::format_args!($($f)*) ) -} diff --git a/rust/macros/fmt.rs b/rust/macros/fmt.rs new file mode 100644 index 000000000000..edc37c220a89 --- /dev/null +++ b/rust/macros/fmt.rs @@ -0,0 +1,99 @@ +// 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 = input.into_iter(); + + let first_opt = input.next(); + let first_owned_str; + let mut names = BTreeSet::new(); + let first_lit = { + let Some((mut first_str, first_lit)) = (match first_opt.as_ref() { + Some(TokenTree::Literal(first_lit)) => { + first_owned_str = first_lit.to_string(); + Some(first_owned_str.as_str()).and_then(|first| { + let first = first.strip_prefix('"')?; + let first = first.strip_suffix('"')?; + Some((first, first_lit)) + }) + } + _ => None, + }) else { + return first_opt.into_iter().chain(input).collect(); + }; + while let Some((_, rest)) = first_str.split_once('{') { + first_str = rest; + if let Some(rest) = first_str.strip_prefix('{') { + first_str = rest; + continue; + } + if let Some((name, rest)) = first_str.split_once('}') { + first_str = rest; + let name = name.split_once(':').map_or(name, |(name, _)| name); + if !name.is_empty() && !name.chars().all(|c| c.is_ascii_digit()) { + names.insert(name); + } + } + } + first_lit + }; + + let first_span = first_lit.span(); + let adapter = quote_spanned! { + first_span => ::kernel::fmt::Adapter + }; + + let mut args = TokenStream::from_iter(first_opt); + { + let mut flush = |args: &mut TokenStream, current: &mut TokenStream| { + let current = std::mem::take(current); + if !current.is_empty() { + let (lhs, rhs) = (|| { + let mut current = current.into_iter(); + let mut acc = TokenStream::new(); + while let Some(tt) = current.next() { + // Split on `=` only once to handle cases like `a = b = c`. + if matches!(&tt, TokenTree::Punct(p) if p.as_char() == '=') { + names.remove(acc.to_string().as_str()); + // Include the `=` itself to keep the handling below uniform. + acc.extend([tt]); + return (Some(acc), current.collect::<TokenStream>()); + } + acc.extend([tt]); + } + (None, acc) + })(); + args.extend(quote_spanned! { + first_span => #lhs #adapter(&#rhs) + }); + } + }; + + let mut current = TokenStream::new(); + for tt in input { + match &tt { + TokenTree::Punct(p) if p.as_char() == ',' => { + flush(&mut args, &mut current); + &mut args + } + _ => &mut current, + } + .extend([tt]); + } + flush(&mut args, &mut current); + } + + for name in names { + let name = Ident::new(name, first_span); + args.extend(quote_spanned! { + first_span => , #name = #adapter(&#name) + }); + } + + quote_spanned! { + first_span => ::core::format_args!(#args) + } +} diff --git a/rust/macros/lib.rs b/rust/macros/lib.rs index fa847cf3a9b5..980e70d253e4 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) -> TokenStream { export::export(attr, ts) }

+/// Like [`core::format_args!`], but automatically wraps arguments in [`kernel::fmt::Adapter`]. +/// +/// This macro allows generating `core::fmt::Arguments` while ensuring that each argument is wrapped +/// with `::kernel::fmt::Adapter`, which customizes formatting behavior for kernel 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 => $($tt:tt)*) => {{ let mut tokens = ::proc_macro::TokenStream::new(); { + #[allow(unused_variables)] let span = $span; quote_spanned!(@proc tokens span $($tt)*); } @@ -146,6 +147,12 @@ macro_rules! quote_spanned { )]); quote_spanned!(@proc $v $span $($tt)*); }; + (@proc $v:ident $span:ident & $($tt:tt)*) => { + $v.extend([::proc_macro::TokenTree::Punct( + ::proc_macro::Punct::new('&', ::proc_macro::Spacing::Alone), + )]); + quote_spanned!(@proc $v $span $($tt)*); + }; (@proc $v:ident $span:ident _ $($tt:tt)*) => { $v.extend([::proc_macro::TokenTree::Ident( ::proc_macro::Ident::new("_", $span), diff --git a/scripts/rustdoc_test_gen.rs b/scripts/rustdoc_test_gen.rs index 1ca253594d38..507d36875196 100644 --- a/scripts/rustdoc_test_gen.rs +++ b/scripts/rustdoc_test_gen.rs @@ -201,7 +201,7 @@ macro_rules! assert_eq {{ // This follows the syntax for declaring test metadata in the proposed KTAP v2 spec, which may // be used for the proposed KUnit test attributes API. Thus hopefully this will make migration // easier later on. - ::kernel::kunit::info(format_args!(" # {kunit_name}.location: {real_path}:{line}\n")); + ::kernel::kunit::info(fmt!(" # {kunit_name}.location: {real_path}:{line}\n"));

/// The anchor where the test code body starts. #[allow(unused)]

`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.

C-String literals were added in Rust 1.77, while our MSRV is 1.78. Thus opportunistically replace instances of `kernel::c_str!` with C-String literals where other code changes were already necessary or where existing code triggered clippy lints; the rest will be done in a later commit.

Link: https://github.com/Rust-for-Linux/linux/commit/faa3cbcca03d0dec8f8e43f1d8d5c... [0] Acked-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Reviewed-by: Alice Ryhl aliceryhl@google.com Signed-off-by: Tamir Duberstein tamird@gmail.com --- drivers/gpu/drm/drm_panic_qr.rs | 2 +- rust/kernel/auxiliary.rs | 4 +- rust/kernel/configfs.rs | 4 +- rust/kernel/cpufreq.rs | 2 +- rust/kernel/device.rs | 4 +- rust/kernel/drm/device.rs | 4 +- rust/kernel/error.rs | 4 +- rust/kernel/firmware.rs | 11 +- rust/kernel/kunit.rs | 6 +- rust/kernel/miscdevice.rs | 2 +- rust/kernel/net/phy.rs | 2 +- rust/kernel/of.rs | 2 +- rust/kernel/prelude.rs | 5 +- rust/kernel/seq_file.rs | 4 +- rust/kernel/str.rs | 394 +++++++++++----------------------------- rust/kernel/sync/condvar.rs | 2 +- rust/kernel/sync/lock.rs | 2 +- rust/kernel/sync/lock/global.rs | 2 +- samples/rust/rust_configfs.rs | 2 +- 19 files changed, 140 insertions(+), 318 deletions(-)

diff --git a/drivers/gpu/drm/drm_panic_qr.rs b/drivers/gpu/drm/drm_panic_qr.rs index 6b59d19ab631..fea062cc0383 100644 --- a/drivers/gpu/drm/drm_panic_qr.rs +++ b/drivers/gpu/drm/drm_panic_qr.rs @@ -948,7 +948,7 @@ fn draw_all(&mut self, data: impl Iterator<Item = u8>) { // nul-terminated string. let url_cstr: &CStr = unsafe { CStr::from_char_ptr(url) }; let segments = &[ - &Segment::Binary(url_cstr.as_bytes()), + &Segment::Binary(url_cstr.to_bytes()), &Segment::Numeric(&data_slice[0..data_len]), ]; match EncodedMsg::new(segments, tmp_slice) { diff --git a/rust/kernel/auxiliary.rs b/rust/kernel/auxiliary.rs index d2cfe1eeefb6..89d961407adb 100644 --- a/rust/kernel/auxiliary.rs +++ b/rust/kernel/auxiliary.rs @@ -111,8 +111,8 @@ macro_rules! module_auxiliary_driver { impl DeviceId { /// Create a new [`DeviceId`] from name. pub const fn new(modname: &'static CStr, name: &'static CStr) -> Self { - let name = name.as_bytes_with_nul(); - let modname = modname.as_bytes_with_nul(); + let name = name.to_bytes_with_nul(); + let modname = modname.to_bytes_with_nul();

// TODO: Replace with `bindings::auxiliary_device_id::default()` once stabilized for // `const`. diff --git a/rust/kernel/configfs.rs b/rust/kernel/configfs.rs index aafef70b7177..d4797c41ba77 100644 --- a/rust/kernel/configfs.rs +++ b/rust/kernel/configfs.rs @@ -263,7 +263,7 @@ pub fn new( try_pin_init!(Self { group <- pin_init::zeroed().chain(|v: &mut Opaquebindings::config_group| { let place = v.get(); - let name = name.as_bytes_with_nul().as_ptr(); + let name = name.to_bytes_with_nul().as_ptr(); // SAFETY: It is safe to initialize a group once it has been zeroed. unsafe { bindings::config_group_init_type_name(place, name.cast(), item_type.as_ptr()) @@ -613,7 +613,7 @@ impl<const ID: u64, O, Data> Attribute<ID, O, Data> pub const fn new(name: &'static CStr) -> Self { Self { attribute: Opaque::new(bindings::configfs_attribute { - ca_name: name.as_char_ptr(), + ca_name: crate::str::as_char_ptr_in_const_context(name), ca_owner: core::ptr::null_mut(), ca_mode: 0o660, show: Some(Self::show), diff --git a/rust/kernel/cpufreq.rs b/rust/kernel/cpufreq.rs index e8d231971276..71d601f7c261 100644 --- a/rust/kernel/cpufreq.rs +++ b/rust/kernel/cpufreq.rs @@ -1018,7 +1018,7 @@ impl<T: Driver> Registration<T> { };

const fn copy_name(name: &'static CStr) -> [c_char; CPUFREQ_NAME_LEN] { - let src = name.as_bytes_with_nul(); + let src = name.to_bytes_with_nul(); let mut dst = [0; CPUFREQ_NAME_LEN];

build_assert!(src.len() <= CPUFREQ_NAME_LEN); diff --git a/rust/kernel/device.rs b/rust/kernel/device.rs index 86b945576780..8cc2d818dca5 100644 --- a/rust/kernel/device.rs +++ b/rust/kernel/device.rs @@ -12,7 +12,7 @@ use core::{fmt, marker::PhantomData, ptr};

#[cfg(CONFIG_PRINTK)] -use crate::c_str; +use crate::str::CStrExt as _;

/// A reference-counted device. /// @@ -197,7 +197,7 @@ unsafe fn printk(&self, klevel: &[u8], msg: fmt::Arguments<'_>) { bindings::_dev_printk( klevel.as_ptr().cast::crate::ffi::c_char(), self.as_raw(), - c_str!("%pA").as_char_ptr(), + c"%pA".as_char_ptr(), core::ptr::from_ref(&msg).cast::crate::ffi::c_void(), ) }; diff --git a/rust/kernel/drm/device.rs b/rust/kernel/drm/device.rs index b7ee3c464a12..998b942b6dd8 100644 --- a/rust/kernel/drm/device.rs +++ b/rust/kernel/drm/device.rs @@ -83,8 +83,8 @@ impl<T: drm::Driver> Device<T> { major: T::INFO.major, minor: T::INFO.minor, patchlevel: T::INFO.patchlevel, - name: T::INFO.name.as_char_ptr().cast_mut(), - desc: T::INFO.desc.as_char_ptr().cast_mut(), + name: crate::str::as_char_ptr_in_const_context(T::INFO.name).cast_mut(), + desc: crate::str::as_char_ptr_in_const_context(T::INFO.desc).cast_mut(),

driver_features: drm::driver::FEAT_GEM, ioctls: T::IOCTLS.as_ptr(), diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs index 6277af1c1baa..94ef4648827e 100644 --- a/rust/kernel/error.rs +++ b/rust/kernel/error.rs @@ -164,6 +164,8 @@ 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) }) } @@ -188,7 +190,7 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { Some(name) => f .debug_tuple( // SAFETY: These strings are ASCII-only. - unsafe { core::str::from_utf8_unchecked(name) }, + unsafe { core::str::from_utf8_unchecked(name.to_bytes()) }, ) .finish(), } diff --git a/rust/kernel/firmware.rs b/rust/kernel/firmware.rs index be684e860ed2..4adcf39b475e 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)

-use crate::{bindings, device::Device, error::Error, error::Result, ffi, str::CStr}; +use crate::{ + bindings, + device::Device, + error::Error, + error::Result, + ffi, + str::{CStr, CStrExt as _}, +}; use core::ptr::NonNull;

/// # Invariants @@ -291,7 +298,7 @@ const fn push_module_name(self) -> Self { let module_name = this.module_name;

if !this.module_name.is_empty() { - this = this.push_internal(module_name.as_bytes_with_nul()); + this = this.push_internal(module_name.to_bytes_with_nul());

if N != 0 { // Re-use the space taken by the NULL terminator and swap it with the '.' separator. diff --git a/rust/kernel/kunit.rs b/rust/kernel/kunit.rs index 3539edbceaf5..6f80dc673974 100644 --- a/rust/kernel/kunit.rs +++ b/rust/kernel/kunit.rs @@ -102,12 +102,12 @@ unsafe impl Sync for Location {} unsafe impl Sync for UnaryAssert {}

static LOCATION: Location = Location($crate::bindings::kunit_loc { - file: FILE.as_char_ptr(), + file: $crate::str::as_char_ptr_in_const_context(FILE), line: LINE, }); static ASSERTION: UnaryAssert = UnaryAssert($crate::bindings::kunit_unary_assert { assert: $crate::bindings::kunit_assert {}, - condition: CONDITION.as_char_ptr(), + condition: $crate::str::as_char_ptr_in_const_context(CONDITION), expected_true: true, });

@@ -202,7 +202,7 @@ pub const fn kunit_case( ) -> kernel::bindings::kunit_case { kernel::bindings::kunit_case { run_case: Some(run_case), - name: name.as_char_ptr(), + name: kernel::str::as_char_ptr_in_const_context(name), attr: kernel::bindings::kunit_attributes { speed: kernel::bindings::kunit_speed_KUNIT_SPEED_NORMAL, }, diff --git a/rust/kernel/miscdevice.rs b/rust/kernel/miscdevice.rs index 288f40e79906..b5b2e3cc158f 100644 --- a/rust/kernel/miscdevice.rs +++ b/rust/kernel/miscdevice.rs @@ -35,7 +35,7 @@ pub const fn into_raw<T: MiscDevice>(self) -> bindings::miscdevice { // SAFETY: All zeros is valid for this C type. let mut result: bindings::miscdevice = unsafe { MaybeUninit::zeroed().assume_init() }; result.minor = bindings::MISC_DYNAMIC_MINOR as ffi::c_int; - result.name = self.name.as_char_ptr(); + result.name = crate::str::as_char_ptr_in_const_context(self.name); result.fops = MiscdeviceVTable::<T>::build(); result } diff --git a/rust/kernel/net/phy.rs b/rust/kernel/net/phy.rs index 65ac4d59ad77..c420e5ecab4b 100644 --- a/rust/kernel/net/phy.rs +++ b/rust/kernel/net/phy.rs @@ -505,7 +505,7 @@ unsafe impl Sync for DriverVTable {} pub const fn create_phy_driver<T: Driver>() -> DriverVTable { // INVARIANT: All the fields of `struct phy_driver` are initialized properly. DriverVTable(Opaque::new(bindings::phy_driver { - name: T::NAME.as_char_ptr().cast_mut(), + name: crate::str::as_char_ptr_in_const_context(T::NAME).cast_mut(), flags: T::FLAGS, phy_id: T::PHY_DEVICE_ID.id, phy_id_mask: T::PHY_DEVICE_ID.mask_as_int(), diff --git a/rust/kernel/of.rs b/rust/kernel/of.rs index 40d1bd13682c..5cf50979c1e8 100644 --- a/rust/kernel/of.rs +++ b/rust/kernel/of.rs @@ -29,7 +29,7 @@ fn index(&self) -> usize { impl DeviceId { /// Create a new device id from an OF 'compatible' string. pub const fn new(compatible: &'static CStr) -> Self { - let src = compatible.as_bytes_with_nul(); + let src = compatible.to_bytes_with_nul(); // Replace with `bindings::of_device_id::default()` once stabilized for `const`. // SAFETY: FFI type is valid to be zero-initialized. let mut of: bindings::of_device_id = unsafe { core::mem::zeroed() }; diff --git a/rust/kernel/prelude.rs b/rust/kernel/prelude.rs index 41cebd906c4c..244b660fa835 100644 --- a/rust/kernel/prelude.rs +++ b/rust/kernel/prelude.rs @@ -40,7 +40,10 @@

pub use super::error::{code::*, Error, Result};

-pub use super::{str::CStr, ThisModule}; +pub use super::{ + str::{CStr, CStrExt as _}, + ThisModule, +};

pub use super::init::InPlaceInit;

diff --git a/rust/kernel/seq_file.rs b/rust/kernel/seq_file.rs index 05c9b7bec727..c26e8507863a 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)

-use crate::{bindings, c_str, types::NotThreadSafe, types::Opaque}; +use crate::{bindings, str::CStrExt as _, types::NotThreadSafe, types::Opaque};

/// A utility for generating the contents of a seq file. #[repr(transparent)] @@ -36,7 +36,7 @@ pub fn call_printf(&self, args: core::fmt::Arguments<'_>) { unsafe { bindings::seq_printf( self.inner.get(), - c_str!("%pA").as_char_ptr(), + c"%pA".as_char_ptr(), core::ptr::from_ref(&args).cast::crate::ffi::c_void(), ); } diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs index d3fa4b703d35..5c365646c0e1 100644 --- a/rust/kernel/str.rs +++ b/rust/kernel/str.rs @@ -4,7 +4,7 @@

use crate::alloc::{flags::*, AllocError, KVec}; use core::fmt::{self, Write}; -use core::ops::{self, Deref, DerefMut, Index}; +use core::ops::{Deref, DerefMut, Index};

use crate::prelude::*;

@@ -57,11 +57,11 @@ impl crate::fmt::Display for BStr { /// # use kernel::{prelude::fmt, b_str, str::{BStr, CString}}; /// let ascii = b_str!("Hello, BStr!"); /// let s = CString::try_from_fmt(fmt!("{}", ascii))?; - /// assert_eq!(s.as_bytes(), "Hello, BStr!".as_bytes()); + /// assert_eq!(s.to_bytes(), "Hello, BStr!".as_bytes()); /// /// let non_ascii = b_str!("🦀"); /// let s = CString::try_from_fmt(fmt!("{}", non_ascii))?; - /// assert_eq!(s.as_bytes(), "\xf0\x9f\xa6\x80".as_bytes()); + /// assert_eq!(s.to_bytes(), "\xf0\x9f\xa6\x80".as_bytes()); /// # Ok::<(), kernel::error::Error>(()) /// ``` fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { @@ -89,11 +89,11 @@ impl fmt::Debug for BStr { /// // Embedded double quotes are escaped. /// let ascii = b_str!("Hello, "BStr"!"); /// let s = CString::try_from_fmt(fmt!("{:?}", ascii))?; - /// assert_eq!(s.as_bytes(), ""Hello, \"BStr\"!"".as_bytes()); + /// assert_eq!(s.to_bytes(), ""Hello, \"BStr\"!"".as_bytes()); /// /// let non_ascii = b_str!("😺"); /// let s = CString::try_from_fmt(fmt!("{:?}", non_ascii))?; - /// assert_eq!(s.as_bytes(), ""\xf0\x9f\x98\xba"".as_bytes()); + /// assert_eq!(s.to_bytes(), ""\xf0\x9f\x98\xba"".as_bytes()); /// # Ok::<(), kernel::error::Error>(()) /// ``` fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { @@ -175,55 +175,19 @@ macro_rules! b_str { }}; }

-/// Possible errors when using conversion functions in [`CStr`]. -#[derive(Debug, Clone, Copy)] -pub enum CStrConvertError { - /// Supplied bytes contain an interior `NUL`. - InteriorNul, +pub use core::ffi::CStr;

- /// Supplied bytes are not terminated by `NUL`. - NotNulTerminated, +/// Returns a C pointer to the string. +// It is a free function rather than a method on an extension trait because: +// +// - error[E0379]: functions in trait impls cannot be declared const +#[inline] +pub const fn as_char_ptr_in_const_context(c_str: &CStr) -> *const crate::ffi::c_char { + c_str.as_ptr().cast() }

-impl From<CStrConvertError> for Error { - #[inline] - fn from(_: CStrConvertError) -> Error { - EINVAL - } -} - -/// A string that is guaranteed to have exactly one `NUL` byte, which is at 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() == 0 - } - +/// Extensions to [`CStr`]. +pub trait CStrExt { /// Wraps a raw C string pointer. /// /// # Safety @@ -231,54 +195,9 @@ 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 `ptr` /// must not be mutated. - #[inline] - pub unsafe fn from_char_ptr<'a>(ptr: *const crate::ffi::c_char) -> &'a Self { - // SAFETY: The safety precondition guarantees `ptr` is a valid pointer - // to a `NUL`-terminated C string. - let len = unsafe { bindings::strlen(ptr) } + 1; - // SAFETY: Lifetime guaranteed by the safety precondition. - let bytes = unsafe { core::slice::from_raw_parts(ptr.cast(), len) }; - // SAFETY: As `len` is returned by `strlen`, `bytes` does not contain 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, CStrConvertError> { - if bytes.is_empty() { - return Err(CStrConvertError::NotNulTerminated); - } - if bytes[bytes.len() - 1] != 0 { - return Err(CStrConvertError::NotNulTerminated); - } - let mut i = 0; - // `i + 1 < bytes.len()` allows LLVM to optimize away bounds checking, - // while it couldn't optimize away bounds checks for `i < bytes.len() - 1`. - while i + 1 < bytes.len() { - if bytes[i] == 0 { - return Err(CStrConvertError::InteriorNul); - } - i += 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]) -> &CStr { - // SAFETY: Properties of `bytes` guaranteed by the safety precondition. - unsafe { core::mem::transmute(bytes) } - } + // This function exists to paper over the fact that `CStr::from_ptr` takes a `*const + // core::ffi::c_char` rather than a `*const crate::ffi::c_char`. + unsafe fn from_char_ptr<'a>(ptr: *const crate::ffi::c_char) -> &'a Self;

/// Creates a mutable [`CStr`] from a `[u8]` without performing any /// additional checks. @@ -287,77 +206,16 @@ pub const fn from_bytes_with_nul(bytes: &[u8]) -> Result<&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 precondition. - unsafe { &mut *(core::ptr::from_mut(bytes) as *mut CStr) } - } + unsafe fn from_bytes_with_nul_unchecked_mut(bytes: &mut [u8]) -> &mut Self;

/// Returns a C pointer to the string. - #[inline] - pub const fn as_char_ptr(&self) -> *const crate::ffi::c_char { - self.0.as_ptr() - } - - /// Convert the string to a byte slice without the trailing `NUL` byte. - #[inline] - pub fn as_bytes(&self) -> &[u8] { - &self.0[..self.len()] - } - - /// Convert the string to a byte slice containing the trailing `NUL` byte. - #[inline] - pub const fn as_bytes_with_nul(&self) -> &[u8] { - &self.0 - } - - /// 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 failed. - /// - /// # Examples - /// - /// ``` - /// # use kernel::str::CStr; - /// let cstr = 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 for - /// valid UTF-8. - /// - /// # Safety - /// - /// The contents must be valid UTF-8. - /// - /// # Examples - /// - /// ``` - /// # use kernel::c_str; - /// # use kernel::str::CStr; - /// let bar = c_str!("ツ"); - /// // SAFETY: String literals are guaranteed to be valid UTF-8 - /// // by the Rust compiler. - /// assert_eq!(unsafe { bar.as_str_unchecked() }, "ツ"); - /// ``` - #[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` returns a `*const + // core::ffi::c_char` rather than a `*const crate::ffi::c_char`. + fn as_char_ptr(&self) -> *const crate::ffi::c_char;

/// Convert this [`CStr`] into a [`CString`] by allocating memory and /// copying over the string data. - pub fn to_cstring(&self) -> Result<CString, AllocError> { - CString::try_from(self) - } + fn to_cstring(&self) -> Result<CString, AllocError>;

/// Converts this [`CStr`] to its ASCII lower case equivalent in-place. /// @@ -368,11 +226,7 @@ pub fn to_cstring(&self) -> Result<CString, AllocError> { /// [`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);

/// Converts this [`CStr`] to its ASCII upper case equivalent in-place. /// @@ -383,11 +237,7 @@ 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);

/// Returns a copy of this [`CString`] where each character is mapped to its /// ASCII lower case equivalent. @@ -398,13 +248,7 @@ 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<CString, AllocError> { - let mut s = self.to_cstring()?; - - s.make_ascii_lowercase(); - - Ok(s) - } + fn to_ascii_lowercase(&self) -> Result<CString, AllocError>;

/// Returns a copy of this [`CString`] where each character is mapped to its /// ASCII upper case equivalent. @@ -415,13 +259,7 @@ pub fn to_ascii_lowercase(&self) -> Result<CString, AllocError> { /// To uppercase the value in-place, use [`make_ascii_uppercase`]. /// /// [`make_ascii_uppercase`]: str::make_ascii_uppercase - pub fn to_ascii_uppercase(&self) -> Result<CString, AllocError> { - let mut s = self.to_cstring()?; - - s.make_ascii_uppercase(); - - Ok(s) - } + fn to_ascii_uppercase(&self) -> Result<CString, AllocError>; }

impl crate::fmt::Display for CStr { @@ -434,15 +272,15 @@ impl crate::fmt::Display for CStr { /// # use kernel::str::CString; /// let penguin = c_str!("🐧"); /// let s = CString::try_from_fmt(fmt!("{}", penguin))?; - /// assert_eq!(s.as_bytes_with_nul(), "\xf0\x9f\x90\xa7\0".as_bytes()); + /// assert_eq!(s.to_bytes_with_nul(), "\xf0\x9f\x90\xa7\0".as_bytes()); /// /// let ascii = c_str!("so "cool""); /// let s = CString::try_from_fmt(fmt!("{}", ascii))?; - /// assert_eq!(s.as_bytes_with_nul(), "so "cool"\0".as_bytes()); + /// assert_eq!(s.to_bytes_with_nul(), "so "cool"\0".as_bytes()); /// # Ok::<(), kernel::error::Error>(()) /// ``` fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - for &c in self.as_bytes() { + for &c in self.to_bytes() { if (0x20..0x7f).contains(&c) { // Printable character. f.write_char(c as char)?; @@ -454,98 +292,75 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { } }

-impl fmt::Debug for CStr { - /// Formats printable ASCII characters with a double quote on either end, escaping the rest. - /// - /// ``` - /// # use kernel::c_str; - /// # use kernel::prelude::fmt; - /// # use kernel::str::CStr; - /// # use kernel::str::CString; - /// let penguin = c_str!("🐧"); - /// let s = 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 = c_str!("so "cool""); - /// let s = 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'"' => f.write_str("\"")?, - 0x20..=0x7e => f.write_char(c as char)?, - _ => 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 the same layout as `&[u8]` + // (this is technically not guaranteed, but we rely on it here). The pointer 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]) } }

-impl AsRef<BStr> 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 crate::ffi::c_char) -> &'a Self { + // SAFETY: The safety preconditions are the same as for `CStr::from_ptr`. + unsafe { CStr::from_ptr(ptr.cast()) } } -}

-impl Deref for CStr { - type Target = 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 properties of `bytes` are + // guaranteed by the safety precondition and `CStr` has the same layout as `&[u8]` (this is + // technically not guaranteed, but we rely on it here). The pointer 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) } + }

#[inline] - fn deref(&self) -> &Self::Target { - self.as_ref() + fn as_char_ptr(&self) -> *const crate::ffi::c_char { + self.as_ptr().cast() } -}

-impl Index<ops::RangeFrom<usize>> for CStr { - type Output = CStr; + fn to_cstring(&self) -> Result<CString, AllocError> { + CString::try_from(self) + }

- #[inline] - fn index(&self, index: ops::RangeFrom<usize>) -> &Self::Output { - // Delegate bounds checking to slice. - // Assign to _ to mute clippy's unnecessary operation warning. - let _ = &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_lowercase(&mut self) { + // SAFETY: This doesn't introduce or remove NUL bytes in the C string. + unsafe { to_bytes_mut(self) }.make_ascii_lowercase(); } -}

-impl Indexops::RangeFull for CStr { - type Output = CStr; + fn make_ascii_uppercase(&mut self) { + // SAFETY: This doesn't introduce or remove NUL bytes in the C string. + unsafe { to_bytes_mut(self) }.make_ascii_uppercase(); + }

- #[inline] - fn index(&self, _index: ops::RangeFull) -> &Self::Output { - self + fn to_ascii_lowercase(&self) -> Result<CString, AllocError> { + let mut s = self.to_cstring()?; + + s.make_ascii_lowercase(); + + Ok(s) } -}

-mod private { - use core::ops; + fn to_ascii_uppercase(&self) -> Result<CString, AllocError> { + let mut s = self.to_cstring()?;

- // Marker trait for index types that can be forward to `BStr`. - pub trait CStrIndex {} + s.make_ascii_uppercase();

- impl CStrIndex for usize {} - impl CStrIndex for ops::Range<usize> {} - impl CStrIndex for ops::RangeInclusive<usize> {} - impl CStrIndex for ops::RangeToInclusive<usize> {} + Ok(s) + } }

-impl<Idx> Index<Idx> for CStr -where - Idx: private::CStrIndex, - BStr: Index<Idx>, -{ - type Output = <BStr as Index<Idx>>::Output; - +impl AsRef<BStr> 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()) } }

@@ -576,6 +391,13 @@ macro_rules! c_str { mod tests { use super::*;

+ impl Fromcore::ffi::FromBytesWithNulError for Error { + #[inline] + fn from(_: core::ffi::FromBytesWithNulError) -> Error { + EINVAL + } + } + macro_rules! format { ($($f:tt)*) => ({ CString::try_from_fmt(crate::prelude::fmt!($($f)*))?.to_str()? @@ -598,40 +420,28 @@ macro_rules! format {

#[test] fn test_cstr_to_str() -> Result { - let good_bytes = b"\xf0\x9f\xa6\x80\0"; - let checked_cstr = CStr::from_bytes_with_nul(good_bytes)?; - let checked_str = checked_cstr.to_str()?; + let cstr = c"\xf0\x9f\xa6\x80"; + let checked_str = cstr.to_str()?; assert_eq!(checked_str, "🦀"); Ok(()) }

#[test] fn test_cstr_to_str_invalid_utf8() -> Result { - let bad_bytes = b"\xc3\x28\0"; - let checked_cstr = 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 = b"\xf0\x9f\x90\xA7\0"; - let checked_cstr = CStr::from_bytes_with_nul(good_bytes)?; - // SAFETY: The contents come from a string literal which contains valid UTF-8. - let unchecked_str = unsafe { checked_cstr.as_str_unchecked() }; - assert_eq!(unchecked_str, "🐧"); + let cstr = c"\xc3\x28"; + assert!(cstr.to_str().is_err()); Ok(()) }

#[test] fn test_cstr_display() -> Result { - let hello_world = CStr::from_bytes_with_nul(b"hello, world!\0")?; + let hello_world = c"hello, world!"; assert_eq!(format!("{hello_world}"), "hello, world!"); - let non_printables = CStr::from_bytes_with_nul(b"\x01\x09\x0a\0")?; + let non_printables = c"\x01\x09\x0a"; assert_eq!(format!("{non_printables}"), "\x01\x09\x0a"); - let non_ascii = CStr::from_bytes_with_nul(b"d\xe9j\xe0 vu\0")?; + let non_ascii = c"d\xe9j\xe0 vu"; assert_eq!(format!("{non_ascii}"), "d\xe9j\xe0 vu"); - let good_bytes = CStr::from_bytes_with_nul(b"\xf0\x9f\xa6\x80\0")?; + let good_bytes = c"\xf0\x9f\xa6\x80"; assert_eq!(format!("{good_bytes}"), "\xf0\x9f\xa6\x80"); Ok(()) } @@ -650,13 +460,13 @@ fn test_cstr_display_all_bytes() -> Result {

#[test] fn test_cstr_debug() -> Result { - let hello_world = CStr::from_bytes_with_nul(b"hello, world!\0")?; + let hello_world = c"hello, world!"; assert_eq!(format!("{hello_world:?}"), ""hello, world!""); - let non_printables = CStr::from_bytes_with_nul(b"\x01\x09\x0a\0")?; - assert_eq!(format!("{non_printables:?}"), ""\x01\x09\x0a""); - let non_ascii = CStr::from_bytes_with_nul(b"d\xe9j\xe0 vu\0")?; + let non_printables = c"\x01\x09\x0a"; + assert_eq!(format!("{non_printables:?}"), ""\x01\t\n""); + let non_ascii = c"d\xe9j\xe0 vu"; assert_eq!(format!("{non_ascii:?}"), ""d\xe9j\xe0 vu""); - let good_bytes = CStr::from_bytes_with_nul(b"\xf0\x9f\xa6\x80\0")?; + let good_bytes = c"\xf0\x9f\xa6\x80"; assert_eq!(format!("{good_bytes:?}"), ""\xf0\x9f\xa6\x80""); Ok(()) } @@ -843,11 +653,11 @@ fn write_str(&mut self, s: &str) -> fmt::Result { /// use kernel::{str::CString, prelude::fmt}; /// /// let s = CString::try_from_fmt(fmt!("{}{}{}", "abc", 10, 20))?; -/// assert_eq!(s.as_bytes_with_nul(), "abc1020\0".as_bytes()); +/// assert_eq!(s.to_bytes_with_nul(), "abc1020\0".as_bytes()); /// /// let tmp = "testing"; /// let s = CString::try_from_fmt(fmt!("{tmp}{}", 123))?; -/// assert_eq!(s.as_bytes_with_nul(), "testing123\0".as_bytes()); +/// assert_eq!(s.to_bytes_with_nul(), "testing123\0".as_bytes()); /// /// // This fails because it has an embedded `NUL` byte. /// let s = CString::try_from_fmt(fmt!("a\0b{}", 123)); @@ -917,7 +727,7 @@ impl<'a> TryFrom<&'a CStr> for CString { fn try_from(cstr: &'a CStr) -> Result<CString, AllocError> { let mut buf = KVec::new();

- buf.extend_from_slice(cstr.as_bytes_with_nul(), GFP_KERNEL)?; + buf.extend_from_slice(cstr.to_bytes_with_nul(), GFP_KERNEL)?;

// INVARIANT: The `CStr` and `CString` types have the same invariants for // the string data, and we copied it over without changes. diff --git a/rust/kernel/sync/condvar.rs b/rust/kernel/sync/condvar.rs index caebf03f553b..0b6bc7f2878d 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_NORMAL, TASK_UNINTERRUPTIBLE, }, diff --git a/rust/kernel/sync/lock.rs b/rust/kernel/sync/lock.rs index e82fa5be289c..a777a22976e0 100644 --- a/rust/kernel/sync/lock.rs +++ b/rust/kernel/sync/lock.rs @@ -7,7 +7,7 @@

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.

use crate::{ - str::CStr, + str::{CStr, CStrExt as _}, sync::lock::{Backend, Guard, Lock}, sync::{LockClassKey, LockedBy}, types::Opaque, diff --git a/samples/rust/rust_configfs.rs b/samples/rust/rust_configfs.rs index af04bfa35cb2..5005453f874d 100644 --- a/samples/rust/rust_configfs.rs +++ b/samples/rust/rust_configfs.rs @@ -94,7 +94,7 @@ impl configfs::AttributeOperations<0> for Configuration {

fn show(container: &Configuration, page: &mut [u8; PAGE_SIZE]) -> Result<usize> { pr_info!("Show message\n"); - let data = container.message; + let data = container.message.to_bytes(); page[0..data.len()].copy_from_slice(data); Ok(data.len()) }

Clean up references to `kernel::str::CStr`.

Acked-by: Stephen Boyd sboyd@kernel.org Acked-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Reviewed-by: Alice Ryhl aliceryhl@google.com Signed-off-by: Tamir Duberstein tamird@gmail.com --- drivers/gpu/drm/drm_panic_qr.rs | 3 ++- drivers/gpu/nova-core/firmware.rs | 2 +- drivers/gpu/nova-core/nova_core.rs | 2 +- drivers/net/phy/ax88796b_rust.rs | 1 + drivers/net/phy/qt2025.rs | 1 + rust/kernel/auxiliary.rs | 2 +- rust/kernel/clk.rs | 3 +-- rust/kernel/configfs.rs | 1 + rust/kernel/cpufreq.rs | 3 ++- rust/kernel/device.rs | 3 +-- rust/kernel/driver.rs | 4 ++-- rust/kernel/drm/driver.rs | 3 ++- rust/kernel/error.rs | 6 ++---- rust/kernel/faux.rs | 5 ++++- rust/kernel/firmware.rs | 15 ++++----------- rust/kernel/kunit.rs | 6 +++--- rust/kernel/lib.rs | 2 +- rust/kernel/miscdevice.rs | 3 +-- rust/kernel/net/phy.rs | 4 +++- rust/kernel/of.rs | 3 ++- rust/kernel/pci.rs | 2 +- rust/kernel/platform.rs | 2 +- rust/kernel/prelude.rs | 5 +---- rust/kernel/str.rs | 8 +++----- rust/kernel/sync/condvar.rs | 4 ++-- rust/kernel/sync/lock.rs | 4 ++-- rust/kernel/sync/lock/global.rs | 5 +++-- rust/kernel/sync/poll.rs | 1 + rust/kernel/workqueue.rs | 1 + rust/macros/module.rs | 2 +- samples/rust/rust_configfs.rs | 2 ++ samples/rust/rust_driver_auxiliary.rs | 5 +++-- 32 files changed, 57 insertions(+), 56 deletions(-)

diff --git a/drivers/gpu/drm/drm_panic_qr.rs b/drivers/gpu/drm/drm_panic_qr.rs index fea062cc0383..05d4c7b87fc3 100644 --- a/drivers/gpu/drm/drm_panic_qr.rs +++ b/drivers/gpu/drm/drm_panic_qr.rs @@ -27,7 +27,8 @@ //! * https://github.com/erwanvivien/fast_qr //! * https://github.com/bjguillot/qr

-use kernel::{prelude::*, str::CStr}; +use core::ffi::CStr; +use kernel::prelude::*;

#[derive(Debug, Clone, Copy, PartialEq, Eq, Ord, PartialOrd)] struct Version(usize); diff --git a/drivers/gpu/nova-core/firmware.rs b/drivers/gpu/nova-core/firmware.rs index 4b8a38358a4f..562ad048ff99 100644 --- a/drivers/gpu/nova-core/firmware.rs +++ b/drivers/gpu/nova-core/firmware.rs @@ -66,7 +66,7 @@ const fn make_entry_chipset(self, chipset: &str) -> Self { }

pub(crate) const fn create( - module_name: &'static kernel::str::CStr, + module_name: &'static core::ffi::CStr, ) -> firmware::ModInfoBuilder<N> { let mut this = Self(firmware::ModInfoBuilder::new(module_name)); let mut i = 0; diff --git a/drivers/gpu/nova-core/nova_core.rs b/drivers/gpu/nova-core/nova_core.rs index f405d7a99c28..b3f9bfba64d9 100644 --- a/drivers/gpu/nova-core/nova_core.rs +++ b/drivers/gpu/nova-core/nova_core.rs @@ -8,7 +8,7 @@ mod regs; mod util;

-pub(crate) const MODULE_NAME: &kernel::str::CStr = <LocalModule as kernel::ModuleMetadata>::NAME; +pub(crate) const MODULE_NAME: &core::ffi::CStr = <LocalModule as kernel::ModuleMetadata>::NAME;

kernel::module_pci_driver! { type: driver::NovaCore, diff --git a/drivers/net/phy/ax88796b_rust.rs b/drivers/net/phy/ax88796b_rust.rs index 2d24628a4e58..68b8e30ae296 100644 --- a/drivers/net/phy/ax88796b_rust.rs +++ b/drivers/net/phy/ax88796b_rust.rs @@ -4,6 +4,7 @@ //! Rust Asix PHYs driver //! //! C version of this driver: [`drivers/net/phy/ax88796b.c`](./ax88796b.c) +use core::ffi::CStr; use kernel::{ net::phy::{self, reg::C22, DeviceId, Driver}, prelude::*, diff --git a/drivers/net/phy/qt2025.rs b/drivers/net/phy/qt2025.rs index 9ccc75f70219..78ce2866f2b6 100644 --- a/drivers/net/phy/qt2025.rs +++ b/drivers/net/phy/qt2025.rs @@ -9,6 +9,7 @@ //! //! The QT2025 PHY integrates an Intel 8051 micro-controller.

+use core::ffi::CStr; use kernel::error::code; use kernel::firmware::Firmware; use kernel::net::phy::{ diff --git a/rust/kernel/auxiliary.rs b/rust/kernel/auxiliary.rs index 89d961407adb..ff29077d9c2f 100644 --- a/rust/kernel/auxiliary.rs +++ b/rust/kernel/auxiliary.rs @@ -10,11 +10,11 @@ driver, error::{to_result, Result}, prelude::*, - str::CStr, types::{ForeignOwnable, Opaque}, ThisModule, }; use core::{ + ffi::CStr, marker::PhantomData, ptr::{addr_of_mut, NonNull}, }; diff --git a/rust/kernel/clk.rs b/rust/kernel/clk.rs index fb0f259cf231..19ac47ffcbd1 100644 --- a/rust/kernel/clk.rs +++ b/rust/kernel/clk.rs @@ -78,10 +78,9 @@ mod common_clk { use crate::{ device::Device, error::{from_err_ptr, to_result, Result}, - prelude::*, };

- use core::{ops::Deref, ptr}; + use core::{ffi::CStr, ops::Deref, ptr};

/// A reference-counted clock. /// diff --git a/rust/kernel/configfs.rs b/rust/kernel/configfs.rs index 255460d571f6..f76a834d7121 100644 --- a/rust/kernel/configfs.rs +++ b/rust/kernel/configfs.rs @@ -118,6 +118,7 @@ use crate::sync::ArcBorrow; use crate::types::Opaque; use core::cell::UnsafeCell; +use core::ffi::CStr; use core::marker::PhantomData;

/// A configfs subsystem. diff --git a/rust/kernel/cpufreq.rs b/rust/kernel/cpufreq.rs index 0f316dfeb5dd..03eb6babdee2 100644 --- a/rust/kernel/cpufreq.rs +++ b/rust/kernel/cpufreq.rs @@ -26,6 +26,7 @@

use core::{ cell::UnsafeCell, + ffi::CStr, marker::PhantomData, mem::MaybeUninit, ops::{Deref, DerefMut}, @@ -853,7 +854,7 @@ fn register_em(_policy: &mut Policy) { /// /// #[vtable] /// impl cpufreq::Driver for SampleDriver { -/// const NAME: &'static CStr = c"cpufreq-sample"; +/// const NAME: &'static core::ffi::CStr = c"cpufreq-sample"; /// const FLAGS: u16 = cpufreq::flags::NEED_INITIAL_FREQ_CHECK | cpufreq::flags::IS_COOLING_DEV; /// const BOOST_ENABLED: bool = true; /// diff --git a/rust/kernel/device.rs b/rust/kernel/device.rs index 8cc2d818dca5..e27b42cd3bd5 100644 --- a/rust/kernel/device.rs +++ b/rust/kernel/device.rs @@ -6,10 +6,9 @@

use crate::{ bindings, - str::CStr, types::{ARef, Opaque}, }; -use core::{fmt, marker::PhantomData, ptr}; +use core::{ffi::CStr, fmt, marker::PhantomData, ptr};

#[cfg(CONFIG_PRINTK)] use crate::str::CStrExt as _; diff --git a/rust/kernel/driver.rs b/rust/kernel/driver.rs index ec9166cedfa7..9926664d9ba2 100644 --- a/rust/kernel/driver.rs +++ b/rust/kernel/driver.rs @@ -6,8 +6,8 @@ //! register using the [`Registration`] class.

use crate::error::{Error, Result}; -use crate::{device, of, str::CStr, try_pin_init, types::Opaque, ThisModule}; -use core::pin::Pin; +use crate::{device, of, try_pin_init, types::Opaque, ThisModule}; +use core::{ffi::CStr, pin::Pin}; use pin_init::{pin_data, pinned_drop, PinInit};

/// The [`RegistrationOps`] trait serves as generic interface for subsystems (e.g., PCI, Platform, diff --git a/rust/kernel/drm/driver.rs b/rust/kernel/drm/driver.rs index acb638086131..4c30933051c7 100644 --- a/rust/kernel/drm/driver.rs +++ b/rust/kernel/drm/driver.rs @@ -10,11 +10,12 @@ drm, error::{to_result, Result}, prelude::*, - str::CStr, types::ARef, }; use macros::vtable;

+use core::ffi::CStr; + /// Driver use the GEM memory manager. This should be set for all modern drivers. pub(crate) const FEAT_GEM: u32 = bindings::drm_driver_feature_DRIVER_GEM;

diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs index 94ef4648827e..1c7784099ea7 100644 --- a/rust/kernel/error.rs +++ b/rust/kernel/error.rs @@ -4,11 +4,9 @@ //! //! C header: [`include/uapi/asm-generic/errno-base.h`](srctree/include/uapi/asm-generic/errno-base.h)

-use crate::{ - alloc::{layout::LayoutError, AllocError}, - str::CStr, -}; +use crate::alloc::{layout::LayoutError, AllocError};

+use core::ffi::CStr; use core::fmt; use core::num::NonZeroI32; use core::num::TryFromIntError; diff --git a/rust/kernel/faux.rs b/rust/kernel/faux.rs index 8a50fcd4c9bb..d9e5cd265101 100644 --- a/rust/kernel/faux.rs +++ b/rust/kernel/faux.rs @@ -7,7 +7,10 @@ //! C header: [`include/linux/device/faux.h`]

use crate::{bindings, device, error::code::*, prelude::*}; -use core::ptr::{addr_of_mut, null, null_mut, NonNull}; +use core::{ + ffi::CStr, + ptr::{addr_of_mut, null, null_mut, NonNull}, +};

/// The registration of a faux device. /// diff --git a/rust/kernel/firmware.rs b/rust/kernel/firmware.rs index d07849333991..efc80732d5ed 100644 --- a/rust/kernel/firmware.rs +++ b/rust/kernel/firmware.rs @@ -4,15 +4,8 @@ //! //! C header: [`include/linux/firmware.h`](srctree/include/linux/firmware.h)

-use crate::{ - bindings, - device::Device, - error::Error, - error::Result, - ffi, - str::{CStr, CStrExt as _}, -}; -use core::ptr::NonNull; +use crate::{bindings, device::Device, error::Error, error::Result, ffi, str::CStrExt as _}; +use core::{ffi::CStr, ptr::NonNull};

/// # Invariants /// @@ -169,7 +162,7 @@ unsafe impl Sync for Firmware {} /// const DIR: &'static str = "vendor/chip/"; /// const FILES: [&'static str; 3] = [ "foo", "bar", "baz" ]; /// -/// const fn create(module_name: &'static kernel::str::CStr) -> firmware::ModInfoBuilder<N> { +/// const fn create(module_name: &'static core::ffi::CStr) -> firmware::ModInfoBuilder<N> { /// let mut builder = firmware::ModInfoBuilder::new(module_name); /// /// let mut i = 0; @@ -203,7 +196,7 @@ macro_rules! module_firmware { // this macro. Hence, we can neither use `expr` nor `ty`. ($($builder:tt)*) => { const _: () = { - const __MODULE_FIRMWARE_PREFIX: &'static $crate::str::CStr = if cfg!(MODULE) { + const __MODULE_FIRMWARE_PREFIX: &'static ::core::ffi::CStr = if cfg!(MODULE) { c"" } else { <LocalModule as $crate::ModuleMetadata>::NAME diff --git a/rust/kernel/kunit.rs b/rust/kernel/kunit.rs index 1d108e4a6a39..2fe9c7a3611e 100644 --- a/rust/kernel/kunit.rs +++ b/rust/kernel/kunit.rs @@ -57,9 +57,9 @@ macro_rules! kunit_assert { break 'out; }

- static FILE: &'static $crate::str::CStr = $file; + static FILE: &'static ::core::ffi::CStr = $file; static LINE: i32 = ::core::line!() as i32 - $diff; - static CONDITION: &'static $crate::str::CStr = + static CONDITION: &'static ::core::ffi::CStr = $crate::str_to_cstr!(stringify!($condition));

// SAFETY: FFI call without safety requirements. @@ -195,7 +195,7 @@ pub fn is_test_result_ok(t: impl TestResult) -> bool { /// Use [`kunit_case_null`] to generate such a delimiter. #[doc(hidden)] pub const fn kunit_case( - name: &'static kernel::str::CStr, + name: &'static core::ffi::CStr, run_case: unsafe extern "C" fn(*mut kernel::bindings::kunit), ) -> kernel::bindings::kunit_case { kernel::bindings::kunit_case { diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index aadcfaa5c759..3a7e935dd1fc 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -166,7 +166,7 @@ fn init(module: &'static ThisModule) -> impl pin_init::PinInit<Self, error::Erro /// Metadata attached to a [`Module`] or [`InPlaceModule`]. pub trait ModuleMetadata { /// The name of the module as specified in the `module!` macro. - const NAME: &'static crate::str::CStr; + const NAME: &'static core::ffi::CStr; }

/// Equivalent to `THIS_MODULE` in the C API. diff --git a/rust/kernel/miscdevice.rs b/rust/kernel/miscdevice.rs index b5b2e3cc158f..91588b0b3985 100644 --- a/rust/kernel/miscdevice.rs +++ b/rust/kernel/miscdevice.rs @@ -17,10 +17,9 @@ mm::virt::VmaNew, prelude::*, seq_file::SeqFile, - str::CStr, types::{ForeignOwnable, Opaque}, }; -use core::{marker::PhantomData, mem::MaybeUninit, pin::Pin}; +use core::{ffi::CStr, marker::PhantomData, mem::MaybeUninit, pin::Pin};

/// Options for creating a misc device. #[derive(Copy, Clone)] diff --git a/rust/kernel/net/phy.rs b/rust/kernel/net/phy.rs index 236ea516a134..ce80117b4b48 100644 --- a/rust/kernel/net/phy.rs +++ b/rust/kernel/net/phy.rs @@ -7,7 +7,7 @@ //! C headers: [`include/linux/phy.h`](srctree/include/linux/phy.h).

use crate::{error::*, prelude::*, types::Opaque}; -use core::{marker::PhantomData, ptr::addr_of_mut}; +use core::{ffi::CStr, marker::PhantomData, ptr::addr_of_mut};

pub mod reg;

@@ -781,6 +781,7 @@ const fn as_int(&self) -> u32 { /// /// ``` /// # mod module_phy_driver_sample { +/// use core::ffi::CStr; /// use kernel::net::phy::{self, DeviceId}; /// use kernel::prelude::*; /// @@ -808,6 +809,7 @@ const fn as_int(&self) -> u32 { /// This expands to the following code: /// /// ```ignore +/// use core::ffi::CStr; /// use kernel::net::phy::{self, DeviceId}; /// use kernel::prelude::*; /// diff --git a/rust/kernel/of.rs b/rust/kernel/of.rs index 5cf50979c1e8..56facfa7a0eb 100644 --- a/rust/kernel/of.rs +++ b/rust/kernel/of.rs @@ -2,7 +2,8 @@

//! Device Tree / Open Firmware abstractions.

-use crate::{bindings, device_id::RawDeviceId, prelude::*}; +use crate::{bindings, device_id::RawDeviceId}; +use core::ffi::CStr;

/// IdTable type for OF drivers. pub type IdTable<T> = &'static dyn kernel::device_id::IdTable<DeviceId, T>; diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs index 6b94fd7a3ce9..fb6ee7bb6186 100644 --- a/rust/kernel/pci.rs +++ b/rust/kernel/pci.rs @@ -13,11 +13,11 @@ error::{to_result, Result}, io::Io, io::IoRaw, - str::CStr, types::{ARef, ForeignOwnable, Opaque}, ThisModule, }; use core::{ + ffi::CStr, marker::PhantomData, ops::Deref, ptr::{addr_of_mut, NonNull}, diff --git a/rust/kernel/platform.rs b/rust/kernel/platform.rs index 99ad0b132ab6..eddae9726d84 100644 --- a/rust/kernel/platform.rs +++ b/rust/kernel/platform.rs @@ -9,12 +9,12 @@ error::{to_result, Result}, of, prelude::*, - str::CStr, types::{ForeignOwnable, Opaque}, ThisModule, };

use core::{ + ffi::CStr, marker::PhantomData, ptr::{addr_of_mut, NonNull}, }; diff --git a/rust/kernel/prelude.rs b/rust/kernel/prelude.rs index 244b660fa835..3f7ca5a95160 100644 --- a/rust/kernel/prelude.rs +++ b/rust/kernel/prelude.rs @@ -40,10 +40,7 @@

pub use super::error::{code::*, Error, Result};

-pub use super::{ - str::{CStr, CStrExt as _}, - ThisModule, -}; +pub use super::{str::CStrExt as _, ThisModule};

pub use super::init::InPlaceInit;

diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs index ff4aaf627179..41529ba41f9f 100644 --- a/rust/kernel/str.rs +++ b/rust/kernel/str.rs @@ -3,6 +3,7 @@ //! String representations.

use crate::alloc::{flags::*, AllocError, KVec}; +use core::ffi::CStr; use core::fmt::{self, Write}; use core::ops::{Deref, DerefMut, Index};

@@ -175,8 +176,6 @@ macro_rules! b_str { }}; }

-pub use core::ffi::CStr; - /// Returns a C pointer to the string. // It is a free function rather than a method on an extension trait because: // @@ -267,7 +266,6 @@ impl crate::fmt::Display for CStr { /// /// ``` /// # use kernel::prelude::fmt; - /// # use kernel::str::CStr; /// # use kernel::str::CString; /// let penguin = c"🐧"; /// let s = CString::try_from_fmt(fmt!("{}", penguin))?; @@ -376,8 +374,8 @@ fn as_ref(&self) -> &BStr { /// # Examples /// /// ``` +/// # use core::ffi::CStr; /// # use kernel::str_to_cstr; -/// # use kernel::str::CStr; /// const MY_CSTR: &CStr = str_to_cstr!(concat!(file!(), ":", line!(), ": My CStr!")); /// ``` #[macro_export] @@ -387,7 +385,7 @@ macro_rules! str_to_cstr { // too limiting to macro authors, so we rely on the name as a hint instead. ($str:expr) => {{ const S: &str = concat!($str, "\0"); - const C: &$crate::str::CStr = match $crate::str::CStr::from_bytes_with_nul(S.as_bytes()) { + const C: &core::ffi::CStr = match core::ffi::CStr::from_bytes_with_nul(S.as_bytes()) { Ok(v) => v, Err(_) => panic!("string contains interior NUL"), }; diff --git a/rust/kernel/sync/condvar.rs b/rust/kernel/sync/condvar.rs index 0b6bc7f2878d..09bc35feb451 100644 --- a/rust/kernel/sync/condvar.rs +++ b/rust/kernel/sync/condvar.rs @@ -8,14 +8,14 @@ use super::{lock::Backend, lock::Guard, LockClassKey}; use crate::{ ffi::{c_int, c_long}, - str::{CStr, CStrExt as _}, + str::CStrExt as _, task::{ MAX_SCHEDULE_TIMEOUT, TASK_FREEZABLE, TASK_INTERRUPTIBLE, TASK_NORMAL, TASK_UNINTERRUPTIBLE, }, time::Jiffies, types::Opaque, }; -use core::{marker::PhantomPinned, pin::Pin, ptr}; +use core::{ffi::CStr, marker::PhantomPinned, pin::Pin, ptr}; use pin_init::{pin_data, pin_init, PinInit};

/// Creates a [`CondVar`] initialiser with the given name and a newly-created lock class. diff --git a/rust/kernel/sync/lock.rs b/rust/kernel/sync/lock.rs index a777a22976e0..21deff0bb13b 100644 --- a/rust/kernel/sync/lock.rs +++ b/rust/kernel/sync/lock.rs @@ -7,10 +7,10 @@

use super::LockClassKey; use crate::{ - str::{CStr, CStrExt as _}, + str::CStrExt as _, types::{NotThreadSafe, Opaque, ScopeGuard}, }; -use core::{cell::UnsafeCell, marker::PhantomPinned, pin::Pin}; +use core::{cell::UnsafeCell, ffi::CStr, marker::PhantomPinned, pin::Pin}; use pin_init::{pin_data, pin_init, PinInit};

pub mod mutex; diff --git a/rust/kernel/sync/lock/global.rs b/rust/kernel/sync/lock/global.rs index 9caa9b419f09..ab5a3947fdd6 100644 --- a/rust/kernel/sync/lock/global.rs +++ b/rust/kernel/sync/lock/global.rs @@ -5,13 +5,14 @@ //! Support for defining statics containing locks.

use crate::{ - str::{CStr, CStrExt as _}, + str::CStrExt as _, sync::lock::{Backend, Guard, Lock}, sync::{LockClassKey, LockedBy}, types::Opaque, }; use core::{ cell::UnsafeCell, + ffi::CStr, marker::{PhantomData, PhantomPinned}, pin::Pin, }; @@ -267,7 +268,7 @@ macro_rules! global_lock { $pub enum $name {}

impl $crate::sync::lock::GlobalLockBackend for $name { - const NAME: &'static $crate::str::CStr = + const NAME: &'static ::core::ffi::CStr = $crate::str_to_cstr!(::core::stringify!($name)); type Item = $valuety; type Backend = $crate::global_lock_inner!(backend $kind); diff --git a/rust/kernel/sync/poll.rs b/rust/kernel/sync/poll.rs index 339ab6097be7..b5340a904f4a 100644 --- a/rust/kernel/sync/poll.rs +++ b/rust/kernel/sync/poll.rs @@ -11,6 +11,7 @@ sync::{CondVar, LockClassKey}, types::Opaque, }; +use core::ffi::CStr; use core::ops::Deref;

/// Creates a [`PollCondVar`] initialiser with the given name and a newly-created lock class. diff --git a/rust/kernel/workqueue.rs b/rust/kernel/workqueue.rs index 432624c69c72..a87e2311ad7c 100644 --- a/rust/kernel/workqueue.rs +++ b/rust/kernel/workqueue.rs @@ -135,6 +135,7 @@

use crate::alloc::{AllocError, Flags}; use crate::{prelude::*, sync::Arc, sync::LockClassKey, types::Opaque}; +use core::ffi::CStr; use core::marker::PhantomData;

/// Creates a [`Work`] initialiser with the given name and a newly-created lock class. diff --git a/rust/macros/module.rs b/rust/macros/module.rs index 532342a38b6f..bf0995674541 100644 --- a/rust/macros/module.rs +++ b/rust/macros/module.rs @@ -228,7 +228,7 @@ pub(crate) fn module(ts: TokenStream) -> TokenStream { type LocalModule = {type_};

impl ::kernel::ModuleMetadata for {type_} {{ - const NAME: &'static ::kernel::str::CStr = c"{name}"; + const NAME: &'static ::core::ffi::CStr = c"{name}"; }}

// Double nested modules, since then nobody can access the public items inside. diff --git a/samples/rust/rust_configfs.rs b/samples/rust/rust_configfs.rs index ea84c23b784b..3f97ab12c39a 100644 --- a/samples/rust/rust_configfs.rs +++ b/samples/rust/rust_configfs.rs @@ -10,6 +10,8 @@ use kernel::prelude::*; use kernel::sync::Mutex;

+use core::ffi::CStr; + module! { type: RustConfigfs, name: "rust_configfs", diff --git a/samples/rust/rust_driver_auxiliary.rs b/samples/rust/rust_driver_auxiliary.rs index eaac5a94f796..4c9447d14914 100644 --- a/samples/rust/rust_driver_auxiliary.rs +++ b/samples/rust/rust_driver_auxiliary.rs @@ -5,10 +5,11 @@ //! To make this driver probe, QEMU must be run with `-device pci-testdev`.

use kernel::{ - auxiliary, bindings, device::Core, driver, error::Error, pci, prelude::*, str::CStr, - InPlaceModule, + auxiliary, bindings, device::Core, driver, error::Error, pci, prelude::*, InPlaceModule, };

+use core::ffi::CStr; + use pin_init::PinInit;

const MODULE_NAME: &CStr = <LocalModule as kernel::ModuleMetadata>::NAME;