`CStr` became a part of `core` library in Rust 1.75. This change replaces the custom `CStr` implementation with the one from `core`.

`core::CStr` behaves generally the same as the removed implementation, with the following differences:

- It does not implement `Display`. - It does not provide `from_bytes_with_nul_unchecked_mut` method. - It has `as_ptr()` method instead of `as_char_ptr()`, which also returns `*const c_char`.

The first two differences are handled by providing the `CStrExt` trait, with `display()` and `from_bytes_with_nul_unchecked_mut()` methods. `display()` returns a `CStrDisplay` wrapper, with a custom `Display` implementation.

`DerefMut` implementation for `CString` is removed here, as it's not being used anywhere.

Signed-off-by: Michal Rostecki vadorovsky@gmail.com --- v1 -> v2: - Do not remove `c_str` macro. While it's preferred to use C-string literals, there are two cases where `c_str` is helpful: - When working with macros, which already return a Rust string literal (e.g. `stringify!`). - When building macros, where we want to take a Rust string literal as an argument (for caller's convenience), but still use it as a C-string internally. - Use Rust literals as arguments in macros (`new_mutex`, `new_condvar`, `new_mutex`). Use the `c_str` macro to convert these literals to C-string literals. - Use `c_str` in kunit.rs for converting the output of `stringify!` to a `CStr`. - Remove `DerefMut` implementation for `CString`.

v2 -> v3: - Fix the commit message. - Remove redundant braces in `use`, when only one item is imported.

v3 -> v4: - Provide the `CStrExt` trait with `display()` method, which returns a `CStrDisplay` wrapper with `Display` implementation. This addresses the lack of `Display` implementation for `core::ffi::CStr`. - Provide `from_bytes_with_nul_unchecked_mut()` method in `CStrExt`, which might be useful and is going to prevent manual, unsafe casts. - Fix a typo (s/preffered/prefered/).

v4 -> v5: - Keep the `test_cstr_display*` unit tests.

rust/kernel/error.rs | 7 +- rust/kernel/kunit.rs | 18 +- rust/kernel/net/phy.rs | 2 +- rust/kernel/prelude.rs | 4 +- rust/kernel/str.rs | 501 ++++++------------------------------ rust/kernel/sync/condvar.rs | 5 +- rust/kernel/sync/lock.rs | 6 +- rust/kernel/workqueue.rs | 2 +- scripts/rustdoc_test_gen.rs | 4 +- 9 files changed, 111 insertions(+), 438 deletions(-)

diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs index 55280ae9fe40..18808b29604d 100644 --- a/rust/kernel/error.rs +++ b/rust/kernel/error.rs @@ -4,10 +4,11 @@ //! //! C header: [`include/uapi/asm-generic/errno-base.h`](srctree/include/uapi/asm-generic/errno-base.h)

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

use alloc::alloc::LayoutError;

+use core::ffi::CStr; use core::fmt; use core::num::TryFromIntError; use core::str::Utf8Error; @@ -142,7 +143,7 @@ pub fn name(&self) -> Option<&'static CStr> { None } else { // SAFETY: The string returned by `errname` is static and `NUL`-terminated. - Some(unsafe { CStr::from_char_ptr(ptr) }) + Some(unsafe { CStr::from_ptr(ptr) }) } }

@@ -164,7 +165,7 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { None => f.debug_tuple("Error").field(&-self.0).finish(), // SAFETY: These strings are ASCII-only. Some(name) => f - .debug_tuple(unsafe { core::str::from_utf8_unchecked(name) }) + .debug_tuple(unsafe { core::str::from_utf8_unchecked(name.to_bytes()) }) .finish(), } } diff --git a/rust/kernel/kunit.rs b/rust/kernel/kunit.rs index 0ba77276ae7e..79a50ab59af0 100644 --- a/rust/kernel/kunit.rs +++ b/rust/kernel/kunit.rs @@ -56,13 +56,15 @@ macro_rules! kunit_assert { break 'out; }

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

// SAFETY: FFI call without safety requirements. let kunit_test = unsafe { $crate::bindings::kunit_get_current_test() }; if kunit_test.is_null() { + use kernel::str::CStrExt; + // The assertion failed but this task is not running a KUnit test, so we cannot call // KUnit, but at least print an error to the kernel log. This may happen if this // macro is called from an spawned thread in a test (see @@ -71,11 +73,13 @@ macro_rules! kunit_assert { // // This mimics KUnit's failed assertion format. $crate::kunit::err(format_args!( - " # {}: ASSERTION FAILED at {FILE}:{LINE}\n", - $name + " # {}: ASSERTION FAILED at {}:{LINE}\n", + $name.display(), + FILE.display(), )); $crate::kunit::err(format_args!( - " Expected {CONDITION} to be true, but is false\n" + " Expected {} to be true, but is false\n", + CONDITION.display(), )); $crate::kunit::err(format_args!( " Failure not reported to KUnit since this is a non-KUnit task\n" @@ -98,12 +102,12 @@ unsafe impl Sync for Location {} unsafe impl Sync for UnaryAssert {}

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

diff --git a/rust/kernel/net/phy.rs b/rust/kernel/net/phy.rs index fd40b703d224..19f45922ec42 100644 --- a/rust/kernel/net/phy.rs +++ b/rust/kernel/net/phy.rs @@ -502,7 +502,7 @@ 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: T::NAME.as_ptr().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/prelude.rs b/rust/kernel/prelude.rs index b37a0b3180fb..b0969ca78f10 100644 --- a/rust/kernel/prelude.rs +++ b/rust/kernel/prelude.rs @@ -12,7 +12,7 @@ //! ```

#[doc(no_inline)] -pub use core::pin::Pin; +pub use core::{ffi::CStr, pin::Pin};

pub use crate::alloc::{box_ext::BoxExt, flags::*, vec_ext::VecExt};

@@ -35,7 +35,7 @@

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

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

pub use super::init::{InPlaceInit, Init, PinInit};

diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs index bb8d4f41475b..f1acaa377694 100644 --- a/rust/kernel/str.rs +++ b/rust/kernel/str.rs @@ -4,8 +4,9 @@

use crate::alloc::{flags::*, vec_ext::VecExt, AllocError}; use alloc::vec::Vec; +use core::ffi::CStr; use core::fmt::{self, Write}; -use core::ops::{self, Deref, DerefMut, Index}; +use core::ops::Deref;

use crate::error::{code::*, Error};

@@ -41,11 +42,11 @@ impl fmt::Display for BStr { /// # use kernel::{fmt, b_str, str::{BStr, CString}}; /// let ascii = b_str!("Hello, BStr!"); /// let s = CString::try_from_fmt(fmt!("{}", ascii)).unwrap(); - /// 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)).unwrap(); - /// assert_eq!(s.as_bytes(), "\xf0\x9f\xa6\x80".as_bytes()); + /// assert_eq!(s.to_bytes(), "\xf0\x9f\xa6\x80".as_bytes()); /// ``` fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { for &b in &self.0 { @@ -72,11 +73,11 @@ impl fmt::Debug for BStr { /// // Embedded double quotes are escaped. /// let ascii = b_str!("Hello, "BStr"!"); /// let s = CString::try_from_fmt(fmt!("{:?}", ascii)).unwrap(); - /// 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)).unwrap(); - /// assert_eq!(s.as_bytes(), ""\xf0\x9f\x98\xba"".as_bytes()); + /// assert_eq!(s.to_bytes(), ""\xf0\x9f\x98\xba"".as_bytes()); /// ``` fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { f.write_char('"')?; @@ -128,271 +129,29 @@ 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, +/// Wrapper around [`CStr`] which implements [`Display`](core::fmt::Display). +pub struct CStrDisplay<'a>(&'a CStr);

- /// Supplied bytes are not terminated by `NUL`. - NotNulTerminated, -} - -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 { - // 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. - if self.0.is_empty() { - 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 - } - - /// Wraps a raw C string pointer. - /// - /// # Safety - /// - /// `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 core::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 as _, len as _) }; - // 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) } - } - - /// Creates a mutable [`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 unsafe fn from_bytes_with_nul_unchecked_mut(bytes: &mut [u8]) -> &mut CStr { - // SAFETY: Properties of `bytes` guaranteed by the safety precondition. - unsafe { &mut *(bytes as *mut [u8] as *mut CStr) } - } - - /// Returns a C pointer to the string. - #[inline] - pub const fn as_char_ptr(&self) -> *const core::ffi::c_char { - self.0.as_ptr() as _ - } - - /// 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").unwrap(); - /// assert_eq!(cstr.to_str(), Ok("foo")); - /// ``` - #[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. +impl fmt::Display for CStrDisplay<'_> { + /// Formats printable ASCII characters, escaping the rest. /// /// # 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 { - unsafe { core::str::from_utf8_unchecked(self.as_bytes()) } - } - - /// 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) - } - - /// Converts this [`CStr`] to its ASCII lower case equivalent in-place. - /// - /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z', - /// but non-ASCII letters are unchanged. - /// - /// To return a new lowercased value without modifying the existing one, use - /// [`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(); - } - - /// Converts this [`CStr`] to its ASCII upper case equivalent in-place. - /// - /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z', - /// but non-ASCII letters are unchanged. - /// - /// To return a new uppercased value without modifying the existing one, use - /// [`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(); - } - - /// Returns a copy of this [`CString`] where each character is mapped to its - /// ASCII lower case equivalent. - /// - /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z', - /// but non-ASCII letters are unchanged. - /// - /// 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) - } - - /// Returns a copy of this [`CString`] where each character is mapped to its - /// ASCII upper case equivalent. - /// - /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z', - /// but non-ASCII letters are unchanged. - /// - /// 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) - } -} - -impl fmt::Display for CStr { - /// Formats printable ASCII characters, escaping the rest. - /// - /// ``` + /// # use core::ffi::CStr; /// # use kernel::c_str; /// # use kernel::fmt; - /// # use kernel::str::CStr; - /// # use kernel::str::CString; - /// let penguin = c_str!("🐧"); - /// let s = CString::try_from_fmt(fmt!("{}", penguin)).unwrap(); - /// assert_eq!(s.as_bytes_with_nul(), "\xf0\x9f\x90\xa7\0".as_bytes()); - /// - /// let ascii = c_str!("so "cool""); - /// let s = CString::try_from_fmt(fmt!("{}", ascii)).unwrap(); - /// assert_eq!(s.as_bytes_with_nul(), "so "cool"\0".as_bytes()); + /// # use kernel::str::{CStrExt, CString}; + /// let penguin = c"🐧"; + /// let s = CString::try_from_fmt(fmt!("{}", penguin.display())).unwrap(); + /// assert_eq!(s.to_bytes_with_nul(), "\xf0\x9f\x90\xa7\0".as_bytes()); + /// + /// let ascii = c"so "cool""; + /// let s = CString::try_from_fmt(fmt!("{}", ascii.display())).unwrap(); + /// assert_eq!(s.to_bytes_with_nul(), "so "cool"\0".as_bytes()); /// ``` fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - for &c in self.as_bytes() { + for &c in self.0.to_bytes() { if (0x20..0x7f).contains(&c) { // Printable character. f.write_char(c as char)?; @@ -404,116 +163,70 @@ 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. +/// Extensions to [`CStr`]. +pub trait CStrExt { + /// Returns an object that implements [`Display`](core::fmt::Display) for + /// safely printing a [`CStr`] that may contain non-ASCII data, which are + /// escaped. + /// + /// # Examples /// /// ``` + /// # use core::ffi::CStr; /// # use kernel::c_str; /// # use kernel::fmt; - /// # use kernel::str::CStr; - /// # use kernel::str::CString; - /// let penguin = c_str!("🐧"); - /// let s = CString::try_from_fmt(fmt!("{:?}", penguin)).unwrap(); - /// 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)).unwrap(); - /// assert_eq!(s.as_bytes_with_nul(), ""so \"cool\""\0".as_bytes()); + /// # use kernel::str::{CStrExt, CString}; + /// let penguin = c"🐧"; + /// let s = CString::try_from_fmt(fmt!("{}", penguin.display())).unwrap(); + /// assert_eq!(s.to_bytes_with_nul(), "\xf0\x9f\x90\xa7\0".as_bytes()); + /// + /// let ascii = c"so "cool""; + /// let s = CString::try_from_fmt(fmt!("{}", ascii.display())).unwrap(); + /// assert_eq!(s.to_bytes_with_nul(), "so "cool"\0".as_bytes()); /// ``` - 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{:02x}", c)?, - } - } - f.write_str(""") - } -} - -impl AsRef<BStr> for CStr { - #[inline] - fn as_ref(&self) -> &BStr { - BStr::from_bytes(self.as_bytes()) - } -} - -impl Deref for CStr { - type Target = BStr; - - #[inline] - fn deref(&self) -> &Self::Target { - self.as_ref() - } -} + fn display(&self) -> CStrDisplay<'_>;

-impl Index<ops::RangeFrom<usize>> for CStr { - type Output = CStr; - - #[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..]) } - } + /// Creates a mutable [`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). + unsafe fn from_bytes_with_nul_unchecked_mut(bytes: &mut [u8]) -> &mut Self; }

-impl Indexops::RangeFull for CStr { - type Output = CStr; - - #[inline] - fn index(&self, _index: ops::RangeFull) -> &Self::Output { - self +impl CStrExt for CStr { + fn display(&self) -> CStrDisplay<'_> { + CStrDisplay(self) } -} - -mod private { - use core::ops;

- // Marker trait for index types that can be forward to `BStr`. - pub trait CStrIndex {} - - impl CStrIndex for usize {} - impl CStrIndex for ops::Range<usize> {} - impl CStrIndex for ops::RangeInclusive<usize> {} - impl CStrIndex for ops::RangeToInclusive<usize> {} -} - -impl<Idx> Index<Idx> for CStr -where - Idx: private::CStrIndex, - BStr: Index<Idx>, -{ - type Output = <BStr as Index<Idx>>::Output; - - #[inline] - fn index(&self, index: Idx) -> &Self::Output { - &self.as_ref()[index] + unsafe fn from_bytes_with_nul_unchecked_mut(bytes: &mut [u8]) -> &mut Self { + // SAFETY: Properties of `bytes` guaranteed by the safety precondition. + unsafe { &mut *(bytes as *mut [u8] as *mut CStr) } } }

/// Creates a new [`CStr`] from a string literal. /// -/// The string literal should not contain any `NUL` bytes. +/// This macro is not needed when C-string literals (`c"hello"` syntax) can be +/// used directly, but can be used when a C-string version of a standard string +/// literal is required (often when working with macros). +/// +/// The string should not contain any `NUL` bytes. /// /// # Examples /// /// ``` +/// # use core::ffi::CStr; /// # use kernel::c_str; -/// # use kernel::str::CStr; -/// const MY_CSTR: &CStr = c_str!("My awesome CStr!"); +/// const MY_CSTR: &CStr = c_str!(stringify!(5)); /// ``` #[macro_export] macro_rules! c_str { ($str:expr) => {{ const S: &str = concat!($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"), }; @@ -540,65 +253,6 @@ mod tests { \xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef\ \xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff";

- #[test] - fn test_cstr_to_str() { - let good_bytes = b"\xf0\x9f\xa6\x80\0"; - let checked_cstr = CStr::from_bytes_with_nul(good_bytes).unwrap(); - let checked_str = checked_cstr.to_str().unwrap(); - assert_eq!(checked_str, "🦀"); - } - - #[test] - #[should_panic] - fn test_cstr_to_str_panic() { - let bad_bytes = b"\xc3\x28\0"; - let checked_cstr = CStr::from_bytes_with_nul(bad_bytes).unwrap(); - checked_cstr.to_str().unwrap(); - } - - #[test] - fn test_cstr_as_str_unchecked() { - let good_bytes = b"\xf0\x9f\x90\xA7\0"; - let checked_cstr = CStr::from_bytes_with_nul(good_bytes).unwrap(); - let unchecked_str = unsafe { checked_cstr.as_str_unchecked() }; - assert_eq!(unchecked_str, "🐧"); - } - - #[test] - fn test_cstr_display() { - let hello_world = CStr::from_bytes_with_nul(b"hello, world!\0").unwrap(); - assert_eq!(format!("{}", hello_world), "hello, world!"); - let non_printables = CStr::from_bytes_with_nul(b"\x01\x09\x0a\0").unwrap(); - assert_eq!(format!("{}", non_printables), "\x01\x09\x0a"); - let non_ascii = CStr::from_bytes_with_nul(b"d\xe9j\xe0 vu\0").unwrap(); - assert_eq!(format!("{}", non_ascii), "d\xe9j\xe0 vu"); - let good_bytes = CStr::from_bytes_with_nul(b"\xf0\x9f\xa6\x80\0").unwrap(); - assert_eq!(format!("{}", good_bytes), "\xf0\x9f\xa6\x80"); - } - - #[test] - fn test_cstr_display_all_bytes() { - let mut bytes: [u8; 256] = [0; 256]; - // fill `bytes` with [1..=255] + [0] - for i in u8::MIN..=u8::MAX { - bytes[i as usize] = i.wrapping_add(1); - } - let cstr = CStr::from_bytes_with_nul(&bytes).unwrap(); - assert_eq!(format!("{}", cstr), ALL_ASCII_CHARS); - } - - #[test] - fn test_cstr_debug() { - let hello_world = CStr::from_bytes_with_nul(b"hello, world!\0").unwrap(); - assert_eq!(format!("{:?}", hello_world), ""hello, world!""); - let non_printables = CStr::from_bytes_with_nul(b"\x01\x09\x0a\0").unwrap(); - assert_eq!(format!("{:?}", non_printables), ""\x01\x09\x0a""); - let non_ascii = CStr::from_bytes_with_nul(b"d\xe9j\xe0 vu\0").unwrap(); - assert_eq!(format!("{:?}", non_ascii), ""d\xe9j\xe0 vu""); - let good_bytes = CStr::from_bytes_with_nul(b"\xf0\x9f\xa6\x80\0").unwrap(); - assert_eq!(format!("{:?}", good_bytes), ""\xf0\x9f\xa6\x80""); - } - #[test] fn test_bstr_display() { let hello_world = BStr::from_bytes(b"hello, world!"); @@ -626,6 +280,29 @@ fn test_bstr_debug() { let good_bytes = BStr::from_bytes(b"\xf0\x9f\xa6\x80"); assert_eq!(format!("{:?}", good_bytes), ""\xf0\x9f\xa6\x80""); } + + #[test] + fn test_cstr_display() { + let hello_world = CStr::from_bytes_with_nul(b"hello, world!\0").unwrap(); + assert_eq!(format!("{}", hello_world.display()), "hello, world!"); + let non_printables = CStr::from_bytes_with_nul(b"\x01\x09\x0a\0").unwrap(); + assert_eq!(format!("{}", non_printables.display()), "\x01\x09\x0a"); + let non_ascii = CStr::from_bytes_with_nul(b"d\xe9j\xe0 vu\0").unwrap(); + assert_eq!(format!("{}", non_ascii.display()), "d\xe9j\xe0 vu"); + let good_bytes = CStr::from_bytes_with_nul(b"\xf0\x9f\xa6\x80\0").unwrap(); + assert_eq!(format!("{}", good_bytes.display()), "\xf0\x9f\xa6\x80"); + } + + #[test] + fn test_cstr_display_all_bytes() { + let mut bytes: [u8; 256] = [0; 256]; + // fill `bytes` with [1..=255] + [0] + for i in u8::MIN..=u8::MAX { + bytes[i as usize] = i.wrapping_add(1); + } + let cstr = CStr::from_bytes_with_nul(&bytes).unwrap(); + assert_eq!(format!("{}", cstr.display()), ALL_ASCII_CHARS); + } }

/// Allows formatting of [`fmt::Arguments`] into a raw buffer. @@ -779,11 +456,11 @@ fn write_str(&mut self, s: &str) -> fmt::Result { /// use kernel::{str::CString, fmt}; /// /// let s = CString::try_from_fmt(fmt!("{}{}{}", "abc", 10, 20)).unwrap(); -/// 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)).unwrap(); -/// 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)); @@ -838,21 +515,13 @@ fn deref(&self) -> &Self::Target { } }

-impl DerefMut for CString { - fn deref_mut(&mut self) -> &mut Self::Target { - // SAFETY: A `CString` is always NUL-terminated and contains no other - // NUL bytes. - unsafe { CStr::from_bytes_with_nul_unchecked_mut(self.buf.as_mut_slice()) } - } -} - impl<'a> TryFrom<&'a CStr> for CString { type Error = AllocError;

fn try_from(cstr: &'a CStr) -> Result<CString, AllocError> { let mut buf = Vec::new();

- <Vec<_> as VecExt<_>>::extend_from_slice(&mut buf, cstr.as_bytes_with_nul(), GFP_KERNEL) + <Vec<_> as VecExt<_>>::extend_from_slice(&mut buf, cstr.to_bytes_with_nul(), GFP_KERNEL) .map_err(|_| AllocError)?;

// INVARIANT: The `CStr` and `CString` types have the same invariants for diff --git a/rust/kernel/sync/condvar.rs b/rust/kernel/sync/condvar.rs index 2b306afbe56d..16d1a1cb8d00 100644 --- a/rust/kernel/sync/condvar.rs +++ b/rust/kernel/sync/condvar.rs @@ -9,12 +9,11 @@ use crate::{ init::PinInit, pin_init, - str::CStr, task::{MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE, TASK_NORMAL, TASK_UNINTERRUPTIBLE}, time::Jiffies, types::Opaque, }; -use core::ffi::{c_int, c_long}; +use core::ffi::{c_int, c_long, CStr}; use core::marker::PhantomPinned; use core::ptr; use macros::pin_data; @@ -108,7 +107,7 @@ pub fn new(name: &'static CStr, key: &'static LockClassKey) -> impl PinInit<Self // SAFETY: `slot` is valid while the closure is called and both `name` and `key` have // static lifetimes so they live indefinitely. wait_queue_head <- Opaque::ffi_init(|slot| unsafe { - bindings::__init_waitqueue_head(slot, name.as_char_ptr(), key.as_ptr()) + bindings::__init_waitqueue_head(slot, name.as_ptr(), key.as_ptr()) }), }) } diff --git a/rust/kernel/sync/lock.rs b/rust/kernel/sync/lock.rs index f6c34ca4d819..318ecb5a5916 100644 --- a/rust/kernel/sync/lock.rs +++ b/rust/kernel/sync/lock.rs @@ -6,8 +6,8 @@ //! spinlocks, raw spinlocks) to be provided with minimal effort.

use super::LockClassKey; -use crate::{init::PinInit, pin_init, str::CStr, types::Opaque, types::ScopeGuard}; -use core::{cell::UnsafeCell, marker::PhantomData, marker::PhantomPinned}; +use crate::{init::PinInit, pin_init, types::Opaque, types::ScopeGuard}; +use core::{cell::UnsafeCell, ffi::CStr, marker::PhantomData, marker::PhantomPinned}; use macros::pin_data;

pub mod mutex; @@ -113,7 +113,7 @@ pub fn new(t: T, name: &'static CStr, key: &'static LockClassKey) -> impl PinIni // SAFETY: `slot` is valid while the closure is called and both `name` and `key` have // static lifetimes so they live indefinitely. state <- Opaque::ffi_init(|slot| unsafe { - B::init(slot, name.as_char_ptr(), key.as_ptr()) + B::init(slot, name.as_ptr(), key.as_ptr()) }), }) } diff --git a/rust/kernel/workqueue.rs b/rust/kernel/workqueue.rs index 553a5cba2adc..a6418873e82e 100644 --- a/rust/kernel/workqueue.rs +++ b/rust/kernel/workqueue.rs @@ -380,7 +380,7 @@ pub fn new(name: &'static CStr, key: &'static LockClassKey) -> impl PinInit<Self slot, Some(T::Pointer::run), false, - name.as_char_ptr(), + name.as_ptr(), key.as_ptr(), ) } diff --git a/scripts/rustdoc_test_gen.rs b/scripts/rustdoc_test_gen.rs index 5ebd42ae4a3f..339991ee6885 100644 --- a/scripts/rustdoc_test_gen.rs +++ b/scripts/rustdoc_test_gen.rs @@ -172,7 +172,7 @@ pub extern "C" fn {kunit_name}(__kunit_test: *mut kernel::bindings::kunit) {{ #[allow(unused)] macro_rules! assert {{ ($cond:expr $(,)?) => {{{{ - kernel::kunit_assert!("{kunit_name}", "{real_path}", __DOCTEST_ANCHOR - {line}, $cond); + kernel::kunit_assert!(c"{kunit_name}", c"{real_path}", __DOCTEST_ANCHOR - {line}, $cond); }}}} }}

@@ -180,7 +180,7 @@ macro_rules! assert {{ #[allow(unused)] macro_rules! assert_eq {{ ($left:expr, $right:expr $(,)?) => {{{{ - kernel::kunit_assert_eq!("{kunit_name}", "{real_path}", __DOCTEST_ANCHOR - {line}, $left, $right); + kernel::kunit_assert_eq!(c"{kunit_name}", c"{real_path}", __DOCTEST_ANCHOR - {line}, $left, $right); }}}} }}