diff options
Diffstat (limited to 'rust/kernel/str.rs')
| -rw-r--r-- | rust/kernel/str.rs | 459 |
1 files changed, 343 insertions, 116 deletions
diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs index bb8d4f41475b..5c74e5f77601 100644 --- a/rust/kernel/str.rs +++ b/rust/kernel/str.rs @@ -2,12 +2,16 @@ //! String representations. -use crate::alloc::{flags::*, vec_ext::VecExt, AllocError}; -use alloc::vec::Vec; -use core::fmt::{self, Write}; -use core::ops::{self, Deref, DerefMut, Index}; - -use crate::error::{code::*, Error}; +use crate::{ + alloc::{flags::*, AllocError, KVec}, + error::{to_result, Result}, + fmt::{self, Write}, + prelude::*, +}; +use core::{ + marker::PhantomData, + ops::{self, Deref, DerefMut, Index}, +}; /// Byte string without UTF-8 validity guarantee. #[repr(transparent)] @@ -30,7 +34,24 @@ impl BStr { #[inline] pub const fn from_bytes(bytes: &[u8]) -> &Self { // SAFETY: `BStr` is transparent to `[u8]`. - unsafe { &*(bytes as *const [u8] as *const BStr) } + unsafe { &*(core::ptr::from_ref(bytes) as *const BStr) } + } + + /// Strip a prefix from `self`. Delegates to [`slice::strip_prefix`]. + /// + /// # Examples + /// + /// ``` + /// # use kernel::b_str; + /// assert_eq!(Some(b_str!("bar")), b_str!("foobar").strip_prefix(b_str!("foo"))); + /// assert_eq!(None, b_str!("foobar").strip_prefix(b_str!("bar"))); + /// assert_eq!(Some(b_str!("foobar")), b_str!("foobar").strip_prefix(b_str!(""))); + /// assert_eq!(Some(b_str!("")), b_str!("foobar").strip_prefix(b_str!("foobar"))); + /// ``` + pub fn strip_prefix(&self, pattern: impl AsRef<Self>) -> Option<&BStr> { + self.deref() + .strip_prefix(pattern.as_ref().deref()) + .map(Self::from_bytes) } } @@ -38,14 +59,15 @@ impl 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)).unwrap(); - /// assert_eq!(s.as_bytes(), "Hello, BStr!".as_bytes()); + /// let s = CString::try_from_fmt(fmt!("{ascii}"))?; + /// 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()); + /// let s = CString::try_from_fmt(fmt!("{non_ascii}"))?; + /// assert_eq!(s.to_bytes(), "\\xf0\\x9f\\xa6\\x80".as_bytes()); + /// # Ok::<(), kernel::error::Error>(()) /// ``` fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { for &b in &self.0 { @@ -56,7 +78,7 @@ impl fmt::Display for BStr { b'\r' => f.write_str("\\r")?, // Printable characters. 0x20..=0x7e => f.write_char(b as char)?, - _ => write!(f, "\\x{:02x}", b)?, + _ => write!(f, "\\x{b:02x}")?, } } Ok(()) @@ -68,15 +90,16 @@ 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)).unwrap(); - /// assert_eq!(s.as_bytes(), "\"Hello, \\\"BStr\\\"!\"".as_bytes()); + /// let s = CString::try_from_fmt(fmt!("{ascii:?}"))?; + /// 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()); + /// let s = CString::try_from_fmt(fmt!("{non_ascii:?}"))?; + /// assert_eq!(s.to_bytes(), "\"\\xf0\\x9f\\x98\\xba\"".as_bytes()); + /// # Ok::<(), kernel::error::Error>(()) /// ``` fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { f.write_char('"')?; @@ -91,7 +114,7 @@ impl fmt::Debug for BStr { b'\\' => f.write_str("\\\\")?, // Printable characters. 0x20..=0x7e => f.write_char(b as char)?, - _ => write!(f, "\\x{:02x}", b)?, + _ => write!(f, "\\x{b:02x}")?, } } f.write_char('"') @@ -107,6 +130,35 @@ impl Deref for BStr { } } +impl PartialEq for BStr { + fn eq(&self, other: &Self) -> bool { + self.deref().eq(other.deref()) + } +} + +impl<Idx> Index<Idx> for BStr +where + [u8]: Index<Idx, Output = [u8]>, +{ + type Output = Self; + + fn index(&self, index: Idx) -> &Self::Output { + BStr::from_bytes(&self.0[index]) + } +} + +impl AsRef<BStr> for [u8] { + fn as_ref(&self) -> &BStr { + BStr::from_bytes(self) + } +} + +impl AsRef<BStr> for BStr { + fn as_ref(&self) -> &BStr { + self + } +} + /// Creates a new [`BStr`] from a string literal. /// /// `b_str!` converts the supplied string literal to byte string, so non-ASCII @@ -128,6 +180,15 @@ macro_rules! b_str { }}; } +/// 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 c_char { + c_str.0.as_ptr() +} + /// Possible errors when using conversion functions in [`CStr`]. #[derive(Debug, Clone, Copy)] pub enum CStrConvertError { @@ -162,10 +223,10 @@ impl CStr { /// 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() { + // 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() @@ -185,12 +246,12 @@ impl CStr { /// 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 { + pub unsafe fn from_char_ptr<'a>(ptr: *const 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 _) }; + 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) } @@ -243,27 +304,49 @@ impl CStr { #[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) } + unsafe { &mut *(core::ptr::from_mut(bytes) as *mut CStr) } } /// Returns a C pointer to the string. + /// + /// Using this function in a const context is deprecated in favor of + /// [`as_char_ptr_in_const_context`] in preparation for replacing `CStr` with `core::ffi::CStr` + /// which does not have this method. #[inline] - pub const fn as_char_ptr(&self) -> *const core::ffi::c_char { - self.0.as_ptr() as _ + pub const fn as_char_ptr(&self) -> *const c_char { + as_char_ptr_in_const_context(self) } /// Convert the string to a byte slice without the trailing `NUL` byte. #[inline] - pub fn as_bytes(&self) -> &[u8] { + pub fn to_bytes(&self) -> &[u8] { &self.0[..self.len()] } + /// Convert the string to a byte slice without the trailing `NUL` byte. + /// + /// This function is deprecated in favor of [`Self::to_bytes`] in preparation for replacing + /// `CStr` with `core::ffi::CStr` which does not have this method. + #[inline] + pub fn as_bytes(&self) -> &[u8] { + self.to_bytes() + } + /// Convert the string to a byte slice containing the trailing `NUL` byte. #[inline] - pub const fn as_bytes_with_nul(&self) -> &[u8] { + pub const fn to_bytes_with_nul(&self) -> &[u8] { &self.0 } + /// Convert the string to a byte slice containing the trailing `NUL` byte. + /// + /// This function is deprecated in favor of [`Self::to_bytes_with_nul`] in preparation for + /// replacing `CStr` with `core::ffi::CStr` which does not have this method. + #[inline] + pub const fn as_bytes_with_nul(&self) -> &[u8] { + self.to_bytes_with_nul() + } + /// Yields a [`&str`] slice if the [`CStr`] contains valid UTF-8. /// /// If the contents of the [`CStr`] are valid UTF-8 data, this @@ -274,8 +357,9 @@ impl CStr { /// /// ``` /// # use kernel::str::CStr; - /// let cstr = CStr::from_bytes_with_nul(b"foo\0").unwrap(); + /// 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> { @@ -301,6 +385,7 @@ impl CStr { /// ``` #[inline] pub unsafe fn as_str_unchecked(&self) -> &str { + // SAFETY: TODO. unsafe { core::str::from_utf8_unchecked(self.as_bytes()) } } @@ -380,24 +465,25 @@ impl fmt::Display 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!("🐧"); - /// let s = CString::try_from_fmt(fmt!("{}", penguin)).unwrap(); - /// assert_eq!(s.as_bytes_with_nul(), "\\xf0\\x9f\\x90\\xa7\0".as_bytes()); + /// let s = CString::try_from_fmt(fmt!("{penguin}"))?; + /// 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)).unwrap(); - /// assert_eq!(s.as_bytes_with_nul(), "so \"cool\"\0".as_bytes()); + /// let s = CString::try_from_fmt(fmt!("{ascii}"))?; + /// 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)?; } else { - write!(f, "\\x{:02x}", c)?; + write!(f, "\\x{c:02x}")?; } } Ok(()) @@ -409,17 +495,18 @@ 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!("🐧"); - /// let s = CString::try_from_fmt(fmt!("{:?}", penguin)).unwrap(); + /// 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)).unwrap(); + /// 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("\"")?; @@ -428,7 +515,7 @@ impl fmt::Debug for CStr { // Printable characters. b'\"' => f.write_str("\\\"")?, 0x20..=0x7e => f.write_char(c as char)?, - _ => write!(f, "\\x{:02x}", c)?, + _ => write!(f, "\\x{c:02x}")?, } } f.write_str("\"") @@ -521,12 +608,17 @@ macro_rules! c_str { }}; } -#[cfg(test)] +#[kunit_tests(rust_kernel_str)] mod tests { use super::*; - use alloc::format; - const ALL_ASCII_CHARS: &'static str = + macro_rules! format { + ($($f:tt)*) => ({ + CString::try_from_fmt(fmt!($($f)*))?.to_str()? + }) + } + + const ALL_ASCII_CHARS: &str = "\\x01\\x02\\x03\\x04\\x05\\x06\\x07\\x08\\x09\\x0a\\x0b\\x0c\\x0d\\x0e\\x0f\ \\x10\\x11\\x12\\x13\\x14\\x15\\x16\\x17\\x18\\x19\\x1a\\x1b\\x1c\\x1d\\x1e\\x1f \ !\"#$%&'()*+,-./0123456789:;<=>?@\ @@ -541,90 +633,98 @@ mod tests { \\xf0\\xf1\\xf2\\xf3\\xf4\\xf5\\xf6\\xf7\\xf8\\xf9\\xfa\\xfb\\xfc\\xfd\\xfe\\xff"; #[test] - fn test_cstr_to_str() { + 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).unwrap(); - let checked_str = checked_cstr.to_str().unwrap(); + let checked_cstr = CStr::from_bytes_with_nul(good_bytes)?; + let checked_str = checked_cstr.to_str()?; assert_eq!(checked_str, "🦀"); + Ok(()) } #[test] - #[should_panic] - fn test_cstr_to_str_panic() { + 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).unwrap(); - checked_cstr.to_str().unwrap(); + 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() { + 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).unwrap(); + 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, "🐧"); + Ok(()) } #[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"); + fn test_cstr_display() -> Result { + let hello_world = CStr::from_bytes_with_nul(b"hello, world!\0")?; + 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")?; + assert_eq!(format!("{non_ascii}"), "d\\xe9j\\xe0 vu"); + let good_bytes = CStr::from_bytes_with_nul(b"\xf0\x9f\xa6\x80\0")?; + assert_eq!(format!("{good_bytes}"), "\\xf0\\x9f\\xa6\\x80"); + Ok(()) } #[test] - fn test_cstr_display_all_bytes() { + fn test_cstr_display_all_bytes() -> Result { 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); + let cstr = CStr::from_bytes_with_nul(&bytes)?; + assert_eq!(format!("{cstr}"), ALL_ASCII_CHARS); + Ok(()) } #[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\""); + fn test_cstr_debug() -> Result { + let hello_world = CStr::from_bytes_with_nul(b"hello, world!\0")?; + 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")?; + assert_eq!(format!("{non_ascii:?}"), "\"d\\xe9j\\xe0 vu\""); + let good_bytes = CStr::from_bytes_with_nul(b"\xf0\x9f\xa6\x80\0")?; + assert_eq!(format!("{good_bytes:?}"), "\"\\xf0\\x9f\\xa6\\x80\""); + Ok(()) } #[test] - fn test_bstr_display() { + fn test_bstr_display() -> Result { let hello_world = BStr::from_bytes(b"hello, world!"); - assert_eq!(format!("{}", hello_world), "hello, world!"); + assert_eq!(format!("{hello_world}"), "hello, world!"); let escapes = BStr::from_bytes(b"_\t_\n_\r_\\_\'_\"_"); - assert_eq!(format!("{}", escapes), "_\\t_\\n_\\r_\\_'_\"_"); + assert_eq!(format!("{escapes}"), "_\\t_\\n_\\r_\\_'_\"_"); let others = BStr::from_bytes(b"\x01"); - assert_eq!(format!("{}", others), "\\x01"); + assert_eq!(format!("{others}"), "\\x01"); let non_ascii = BStr::from_bytes(b"d\xe9j\xe0 vu"); - assert_eq!(format!("{}", non_ascii), "d\\xe9j\\xe0 vu"); + assert_eq!(format!("{non_ascii}"), "d\\xe9j\\xe0 vu"); let good_bytes = BStr::from_bytes(b"\xf0\x9f\xa6\x80"); - assert_eq!(format!("{}", good_bytes), "\\xf0\\x9f\\xa6\\x80"); + assert_eq!(format!("{good_bytes}"), "\\xf0\\x9f\\xa6\\x80"); + Ok(()) } #[test] - fn test_bstr_debug() { + fn test_bstr_debug() -> Result { let hello_world = BStr::from_bytes(b"hello, world!"); - assert_eq!(format!("{:?}", hello_world), "\"hello, world!\""); + assert_eq!(format!("{hello_world:?}"), "\"hello, world!\""); let escapes = BStr::from_bytes(b"_\t_\n_\r_\\_\'_\"_"); - assert_eq!(format!("{:?}", escapes), "\"_\\t_\\n_\\r_\\\\_'_\\\"_\""); + assert_eq!(format!("{escapes:?}"), "\"_\\t_\\n_\\r_\\\\_'_\\\"_\""); let others = BStr::from_bytes(b"\x01"); - assert_eq!(format!("{:?}", others), "\"\\x01\""); + assert_eq!(format!("{others:?}"), "\"\\x01\""); let non_ascii = BStr::from_bytes(b"d\xe9j\xe0 vu"); - assert_eq!(format!("{:?}", non_ascii), "\"d\\xe9j\\xe0 vu\""); + assert_eq!(format!("{non_ascii:?}"), "\"d\\xe9j\\xe0 vu\""); let good_bytes = BStr::from_bytes(b"\xf0\x9f\xa6\x80"); - assert_eq!(format!("{:?}", good_bytes), "\"\\xf0\\x9f\\xa6\\x80\""); + assert_eq!(format!("{good_bytes:?}"), "\"\\xf0\\x9f\\xa6\\x80\""); + Ok(()) } } @@ -637,7 +737,7 @@ mod tests { /// /// The memory region between `pos` (inclusive) and `end` (exclusive) is valid for writes if `pos` /// is less than `end`. -pub(crate) struct RawFormatter { +pub struct RawFormatter { // Use `usize` to use `saturating_*` functions. beg: usize, pos: usize, @@ -664,9 +764,9 @@ impl RawFormatter { pub(crate) unsafe fn from_ptrs(pos: *mut u8, end: *mut u8) -> Self { // INVARIANT: The safety requirements guarantee the type invariants. Self { - beg: pos as _, - pos: pos as _, - end: end as _, + beg: pos as usize, + pos: pos as usize, + end: end as usize, } } @@ -678,7 +778,7 @@ impl RawFormatter { /// for the lifetime of the returned [`RawFormatter`]. pub(crate) unsafe fn from_buffer(buf: *mut u8, len: usize) -> Self { let pos = buf as usize; - // INVARIANT: We ensure that `end` is never less then `buf`, and the safety requirements + // INVARIANT: We ensure that `end` is never less than `buf`, and the safety requirements // guarantees that the memory region is valid for writes. Self { pos, @@ -691,11 +791,11 @@ impl RawFormatter { /// /// N.B. It may point to invalid memory. pub(crate) fn pos(&self) -> *mut u8 { - self.pos as _ + self.pos as *mut u8 } /// Returns the number of bytes written to the formatter. - pub(crate) fn bytes_written(&self) -> usize { + pub fn bytes_written(&self) -> usize { self.pos - self.beg } } @@ -729,9 +829,9 @@ impl fmt::Write for RawFormatter { /// Allows formatting of [`fmt::Arguments`] into a raw buffer. /// /// Fails if callers attempt to write more than will fit in the buffer. -pub(crate) struct Formatter(RawFormatter); +pub struct Formatter<'a>(RawFormatter, PhantomData<&'a mut ()>); -impl Formatter { +impl Formatter<'_> { /// Creates a new instance of [`Formatter`] with the given buffer. /// /// # Safety @@ -740,11 +840,18 @@ impl Formatter { /// for the lifetime of the returned [`Formatter`]. pub(crate) unsafe fn from_buffer(buf: *mut u8, len: usize) -> Self { // SAFETY: The safety requirements of this function satisfy those of the callee. - Self(unsafe { RawFormatter::from_buffer(buf, len) }) + Self(unsafe { RawFormatter::from_buffer(buf, len) }, PhantomData) + } + + /// Create a new [`Self`] instance. + pub fn new(buffer: &mut [u8]) -> Self { + // SAFETY: `buffer` is valid for writes for the entire length for + // the lifetime of `Self`. + unsafe { Formatter::from_buffer(buffer.as_mut_ptr(), buffer.len()) } } } -impl Deref for Formatter { +impl Deref for Formatter<'_> { type Target = RawFormatter; fn deref(&self) -> &Self::Target { @@ -752,7 +859,7 @@ impl Deref for Formatter { } } -impl fmt::Write for Formatter { +impl fmt::Write for Formatter<'_> { fn write_str(&mut self, s: &str) -> fmt::Result { self.0.write_str(s)?; @@ -765,6 +872,132 @@ impl fmt::Write for Formatter { } } +/// A mutable reference to a byte buffer where a string can be written into. +/// +/// The buffer will be automatically null terminated after the last written character. +/// +/// # Invariants +/// +/// * The first byte of `buffer` is always zero. +/// * The length of `buffer` is at least 1. +pub(crate) struct NullTerminatedFormatter<'a> { + buffer: &'a mut [u8], +} + +impl<'a> NullTerminatedFormatter<'a> { + /// Create a new [`Self`] instance. + pub(crate) fn new(buffer: &'a mut [u8]) -> Option<NullTerminatedFormatter<'a>> { + *(buffer.first_mut()?) = 0; + + // INVARIANT: + // - We wrote zero to the first byte above. + // - If buffer was not at least length 1, `buffer.first_mut()` would return None. + Some(Self { buffer }) + } +} + +impl Write for NullTerminatedFormatter<'_> { + fn write_str(&mut self, s: &str) -> fmt::Result { + let bytes = s.as_bytes(); + let len = bytes.len(); + + // We want space for a zero. By type invariant, buffer length is always at least 1, so no + // underflow. + if len > self.buffer.len() - 1 { + return Err(fmt::Error); + } + + let buffer = core::mem::take(&mut self.buffer); + // We break the zero start invariant for a short while. + buffer[..len].copy_from_slice(bytes); + // INVARIANT: We checked above that buffer will have size at least 1 after this assignment. + self.buffer = &mut buffer[len..]; + + // INVARIANT: We write zero to the first byte of the buffer. + self.buffer[0] = 0; + + Ok(()) + } +} + +/// # Safety +/// +/// - `string` must point to a null terminated string that is valid for read. +unsafe fn kstrtobool_raw(string: *const u8) -> Result<bool> { + let mut result: bool = false; + + // SAFETY: + // - By function safety requirement, `string` is a valid null-terminated string. + // - `result` is a valid `bool` that we own. + to_result(unsafe { bindings::kstrtobool(string, &mut result) })?; + Ok(result) +} + +/// Convert common user inputs into boolean values using the kernel's `kstrtobool` function. +/// +/// This routine returns `Ok(bool)` if the first character is one of 'YyTt1NnFf0', or +/// \[oO\]\[NnFf\] for "on" and "off". Otherwise it will return `Err(EINVAL)`. +/// +/// # Examples +/// +/// ``` +/// # use kernel::{c_str, str::kstrtobool}; +/// +/// // Lowercase +/// assert_eq!(kstrtobool(c_str!("true")), Ok(true)); +/// assert_eq!(kstrtobool(c_str!("tr")), Ok(true)); +/// assert_eq!(kstrtobool(c_str!("t")), Ok(true)); +/// assert_eq!(kstrtobool(c_str!("twrong")), Ok(true)); +/// assert_eq!(kstrtobool(c_str!("false")), Ok(false)); +/// assert_eq!(kstrtobool(c_str!("f")), Ok(false)); +/// assert_eq!(kstrtobool(c_str!("yes")), Ok(true)); +/// assert_eq!(kstrtobool(c_str!("no")), Ok(false)); +/// assert_eq!(kstrtobool(c_str!("on")), Ok(true)); +/// assert_eq!(kstrtobool(c_str!("off")), Ok(false)); +/// +/// // Camel case +/// assert_eq!(kstrtobool(c_str!("True")), Ok(true)); +/// assert_eq!(kstrtobool(c_str!("False")), Ok(false)); +/// assert_eq!(kstrtobool(c_str!("Yes")), Ok(true)); +/// assert_eq!(kstrtobool(c_str!("No")), Ok(false)); +/// assert_eq!(kstrtobool(c_str!("On")), Ok(true)); +/// assert_eq!(kstrtobool(c_str!("Off")), Ok(false)); +/// +/// // All caps +/// assert_eq!(kstrtobool(c_str!("TRUE")), Ok(true)); +/// assert_eq!(kstrtobool(c_str!("FALSE")), Ok(false)); +/// assert_eq!(kstrtobool(c_str!("YES")), Ok(true)); +/// assert_eq!(kstrtobool(c_str!("NO")), Ok(false)); +/// assert_eq!(kstrtobool(c_str!("ON")), Ok(true)); +/// assert_eq!(kstrtobool(c_str!("OFF")), Ok(false)); +/// +/// // Numeric +/// assert_eq!(kstrtobool(c_str!("1")), Ok(true)); +/// assert_eq!(kstrtobool(c_str!("0")), Ok(false)); +/// +/// // Invalid input +/// assert_eq!(kstrtobool(c_str!("invalid")), Err(EINVAL)); +/// assert_eq!(kstrtobool(c_str!("2")), Err(EINVAL)); +/// ``` +pub fn kstrtobool(string: &CStr) -> Result<bool> { + // SAFETY: + // - The pointer returned by `CStr::as_char_ptr` is guaranteed to be + // null terminated. + // - `string` is live and thus the string is valid for read. + unsafe { kstrtobool_raw(string.as_char_ptr()) } +} + +/// Convert `&[u8]` to `bool` by deferring to [`kernel::str::kstrtobool`]. +/// +/// Only considers at most the first two bytes of `bytes`. +pub fn kstrtobool_bytes(bytes: &[u8]) -> Result<bool> { + // `ktostrbool` only considers the first two bytes of the input. + let stack_string = [*bytes.first().unwrap_or(&0), *bytes.get(1).unwrap_or(&0), 0]; + // SAFETY: `stack_string` is null terminated and it is live on the stack so + // it is valid for read. + unsafe { kstrtobool_raw(stack_string.as_ptr()) } +} + /// An owned 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. @@ -776,21 +1009,22 @@ impl fmt::Write for Formatter { /// # Examples /// /// ``` -/// use kernel::{str::CString, fmt}; +/// use kernel::{str::CString, prelude::fmt}; /// -/// let s = CString::try_from_fmt(fmt!("{}{}{}", "abc", 10, 20)).unwrap(); -/// assert_eq!(s.as_bytes_with_nul(), "abc1020\0".as_bytes()); +/// let s = CString::try_from_fmt(fmt!("{}{}{}", "abc", 10, 20))?; +/// 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()); +/// let s = CString::try_from_fmt(fmt!("{tmp}{}", 123))?; +/// 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)); /// assert_eq!(s.is_ok(), false); +/// # Ok::<(), kernel::error::Error>(()) /// ``` pub struct CString { - buf: Vec<u8>, + buf: KVec<u8>, } impl CString { @@ -803,7 +1037,7 @@ impl CString { let size = f.bytes_written(); // Allocate a vector with the required number of bytes, and write to it. - let mut buf = <Vec<_> as VecExt<_>>::with_capacity(size, GFP_KERNEL)?; + let mut buf = KVec::with_capacity(size, GFP_KERNEL)?; // SAFETY: The buffer stored in `buf` is at least of size `size` and is valid for writes. let mut f = unsafe { Formatter::from_buffer(buf.as_mut_ptr(), size) }; f.write_fmt(args)?; @@ -811,13 +1045,13 @@ impl CString { // SAFETY: The number of bytes that can be written to `f` is bounded by `size`, which is // `buf`'s capacity. The contents of the buffer have been initialised by writes to `f`. - unsafe { buf.set_len(f.bytes_written()) }; + unsafe { buf.inc_len(f.bytes_written()) }; // Check that there are no `NUL` bytes before the end. // SAFETY: The buffer is valid for read because `f.bytes_written()` is bounded by `size` // (which the minimum buffer size) and is non-zero (we wrote at least the `NUL` terminator) // so `f.bytes_written() - 1` doesn't underflow. - let ptr = unsafe { bindings::memchr(buf.as_ptr().cast(), 0, (f.bytes_written() - 1) as _) }; + let ptr = unsafe { bindings::memchr(buf.as_ptr().cast(), 0, f.bytes_written() - 1) }; if !ptr.is_null() { return Err(EINVAL); } @@ -850,10 +1084,9 @@ impl<'a> TryFrom<&'a CStr> for CString { type Error = AllocError; fn try_from(cstr: &'a CStr) -> Result<CString, AllocError> { - let mut buf = Vec::new(); + let mut buf = KVec::new(); - <Vec<_> as VecExt<_>>::extend_from_slice(&mut buf, cstr.as_bytes_with_nul(), GFP_KERNEL) - .map_err(|_| AllocError)?; + 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. @@ -866,9 +1099,3 @@ impl fmt::Debug for CString { fmt::Debug::fmt(&**self, f) } } - -/// A convenience alias for [`core::format_args`]. -#[macro_export] -macro_rules! fmt { - ($($f:tt)*) => ( core::format_args!($($f)*) ) -} |