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-rw-r--r--lib/Kconfig.debug13
-rw-r--r--rust/.gitignore2
-rw-r--r--rust/Makefile29
-rw-r--r--rust/bindings/bindings_helper.h1
-rw-r--r--rust/helpers.c7
-rw-r--r--rust/kernel/kunit.rs163
-rw-r--r--rust/kernel/lib.rs2
-rw-r--r--scripts/.gitignore2
-rw-r--r--scripts/Makefile4
-rw-r--r--scripts/rustdoc_test_builder.rs72
-rw-r--r--scripts/rustdoc_test_gen.rs260
11 files changed, 555 insertions, 0 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index fbc89baf7de6..550cb967b668 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -3010,6 +3010,19 @@ config RUST_BUILD_ASSERT_ALLOW
If unsure, say N.
+config RUST_KERNEL_DOCTESTS
+ bool "Doctests for the `kernel` crate" if !KUNIT_ALL_TESTS
+ depends on RUST && KUNIT=y
+ default KUNIT_ALL_TESTS
+ help
+ This builds the documentation tests of the `kernel` crate
+ as KUnit tests.
+
+ For more information on KUnit and unit tests in general,
+ please refer to the KUnit documentation in Documentation/dev-tools/kunit/.
+
+ If unsure, say N.
+
endmenu # "Rust"
endmenu # Kernel hacking
diff --git a/rust/.gitignore b/rust/.gitignore
index 21552992b401..d3829ffab80b 100644
--- a/rust/.gitignore
+++ b/rust/.gitignore
@@ -2,6 +2,8 @@
bindings_generated.rs
bindings_helpers_generated.rs
+doctests_kernel_generated.rs
+doctests_kernel_generated_kunit.c
uapi_generated.rs
exports_*_generated.h
doc/
diff --git a/rust/Makefile b/rust/Makefile
index 7c9d9f11aec5..92482144c0bb 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -27,6 +27,12 @@ endif
obj-$(CONFIG_RUST) += exports.o
+always-$(CONFIG_RUST_KERNEL_DOCTESTS) += doctests_kernel_generated.rs
+always-$(CONFIG_RUST_KERNEL_DOCTESTS) += doctests_kernel_generated_kunit.c
+
+obj-$(CONFIG_RUST_KERNEL_DOCTESTS) += doctests_kernel_generated.o
+obj-$(CONFIG_RUST_KERNEL_DOCTESTS) += doctests_kernel_generated_kunit.o
+
# Avoids running `$(RUSTC)` for the sysroot when it may not be available.
ifdef CONFIG_RUST
@@ -39,9 +45,11 @@ ifeq ($(quiet),silent_)
cargo_quiet=-q
rust_test_quiet=-q
rustdoc_test_quiet=--test-args -q
+rustdoc_test_kernel_quiet=>/dev/null
else ifeq ($(quiet),quiet_)
rust_test_quiet=-q
rustdoc_test_quiet=--test-args -q
+rustdoc_test_kernel_quiet=>/dev/null
else
cargo_quiet=--verbose
endif
@@ -157,6 +165,27 @@ quiet_cmd_rustdoc_test = RUSTDOC T $<
-L$(objtree)/$(obj)/test --output $(objtree)/$(obj)/doc \
--crate-name $(subst rusttest-,,$@) $<
+quiet_cmd_rustdoc_test_kernel = RUSTDOC TK $<
+ cmd_rustdoc_test_kernel = \
+ rm -rf $(objtree)/$(obj)/test/doctests/kernel; \
+ mkdir -p $(objtree)/$(obj)/test/doctests/kernel; \
+ OBJTREE=$(abspath $(objtree)) \
+ $(RUSTDOC) --test $(rust_flags) \
+ @$(objtree)/include/generated/rustc_cfg \
+ -L$(objtree)/$(obj) --extern alloc --extern kernel \
+ --extern build_error --extern macros \
+ --extern bindings --extern uapi \
+ --no-run --crate-name kernel -Zunstable-options \
+ --test-builder $(objtree)/scripts/rustdoc_test_builder \
+ $< $(rustdoc_test_kernel_quiet); \
+ $(objtree)/scripts/rustdoc_test_gen
+
+%/doctests_kernel_generated.rs %/doctests_kernel_generated_kunit.c: \
+ $(src)/kernel/lib.rs $(obj)/kernel.o \
+ $(objtree)/scripts/rustdoc_test_builder \
+ $(objtree)/scripts/rustdoc_test_gen FORCE
+ $(call if_changed,rustdoc_test_kernel)
+
# We cannot use `-Zpanic-abort-tests` because some tests are dynamic,
# so for the moment we skip `-Cpanic=abort`.
quiet_cmd_rustc_test = RUSTC T $<
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index 3e601ce2548d..0f8d37c31ac2 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -6,6 +6,7 @@
* Sorted alphabetically.
*/
+#include <kunit/test.h>
#include <linux/errname.h>
#include <linux/slab.h>
#include <linux/refcount.h>
diff --git a/rust/helpers.c b/rust/helpers.c
index bb594da56137..49a5e1a4f0ae 100644
--- a/rust/helpers.c
+++ b/rust/helpers.c
@@ -18,6 +18,7 @@
* accidentally exposed.
*/
+#include <kunit/test-bug.h>
#include <linux/bug.h>
#include <linux/build_bug.h>
#include <linux/err.h>
@@ -135,6 +136,12 @@ void rust_helper_put_task_struct(struct task_struct *t)
}
EXPORT_SYMBOL_GPL(rust_helper_put_task_struct);
+struct kunit *rust_helper_kunit_get_current_test(void)
+{
+ return kunit_get_current_test();
+}
+EXPORT_SYMBOL_GPL(rust_helper_kunit_get_current_test);
+
/*
* We use `bindgen`'s `--size_t-is-usize` option to bind the C `size_t` type
* as the Rust `usize` type, so we can use it in contexts where Rust
diff --git a/rust/kernel/kunit.rs b/rust/kernel/kunit.rs
new file mode 100644
index 000000000000..722655b2d62d
--- /dev/null
+++ b/rust/kernel/kunit.rs
@@ -0,0 +1,163 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! KUnit-based macros for Rust unit tests.
+//!
+//! C header: [`include/kunit/test.h`](../../../../../include/kunit/test.h)
+//!
+//! Reference: <https://docs.kernel.org/dev-tools/kunit/index.html>
+
+use core::{ffi::c_void, fmt};
+
+/// Prints a KUnit error-level message.
+///
+/// Public but hidden since it should only be used from KUnit generated code.
+#[doc(hidden)]
+pub fn err(args: fmt::Arguments<'_>) {
+ // SAFETY: The format string is null-terminated and the `%pA` specifier matches the argument we
+ // are passing.
+ #[cfg(CONFIG_PRINTK)]
+ unsafe {
+ bindings::_printk(
+ b"\x013%pA\0".as_ptr() as _,
+ &args as *const _ as *const c_void,
+ );
+ }
+}
+
+/// Prints a KUnit info-level message.
+///
+/// Public but hidden since it should only be used from KUnit generated code.
+#[doc(hidden)]
+pub fn info(args: fmt::Arguments<'_>) {
+ // SAFETY: The format string is null-terminated and the `%pA` specifier matches the argument we
+ // are passing.
+ #[cfg(CONFIG_PRINTK)]
+ unsafe {
+ bindings::_printk(
+ b"\x016%pA\0".as_ptr() as _,
+ &args as *const _ as *const c_void,
+ );
+ }
+}
+
+/// Asserts that a boolean expression is `true` at runtime.
+///
+/// Public but hidden since it should only be used from generated tests.
+///
+/// Unlike the one in `core`, this one does not panic; instead, it is mapped to the KUnit
+/// facilities. See [`assert!`] for more details.
+#[doc(hidden)]
+#[macro_export]
+macro_rules! kunit_assert {
+ ($name:literal, $file:literal, $diff:expr, $condition:expr $(,)?) => {
+ 'out: {
+ // Do nothing if the condition is `true`.
+ if $condition {
+ break 'out;
+ }
+
+ static FILE: &'static $crate::str::CStr = $crate::c_str!($file);
+ static LINE: i32 = core::line!() as i32 - $diff;
+ static CONDITION: &'static $crate::str::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() {
+ // 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
+ // `scripts/rustdoc_test_gen.rs`) or if some non-test code calls this macro by
+ // mistake (it is hidden to prevent that).
+ //
+ // This mimics KUnit's failed assertion format.
+ $crate::kunit::err(format_args!(
+ " # {}: ASSERTION FAILED at {FILE}:{LINE}\n",
+ $name
+ ));
+ $crate::kunit::err(format_args!(
+ " Expected {CONDITION} to be true, but is false\n"
+ ));
+ $crate::kunit::err(format_args!(
+ " Failure not reported to KUnit since this is a non-KUnit task\n"
+ ));
+ break 'out;
+ }
+
+ #[repr(transparent)]
+ struct Location($crate::bindings::kunit_loc);
+
+ #[repr(transparent)]
+ struct UnaryAssert($crate::bindings::kunit_unary_assert);
+
+ // SAFETY: There is only a static instance and in that one the pointer field points to
+ // an immutable C string.
+ unsafe impl Sync for Location {}
+
+ // SAFETY: There is only a static instance and in that one the pointer field points to
+ // an immutable C string.
+ unsafe impl Sync for UnaryAssert {}
+
+ static LOCATION: Location = Location($crate::bindings::kunit_loc {
+ file: FILE.as_char_ptr(),
+ line: LINE,
+ });
+ static ASSERTION: UnaryAssert = UnaryAssert($crate::bindings::kunit_unary_assert {
+ assert: $crate::bindings::kunit_assert {},
+ condition: CONDITION.as_char_ptr(),
+ expected_true: true,
+ });
+
+ // SAFETY:
+ // - FFI call.
+ // - The `kunit_test` pointer is valid because we got it from
+ // `kunit_get_current_test()` and it was not null. This means we are in a KUnit
+ // test, and that the pointer can be passed to KUnit functions and assertions.
+ // - The string pointers (`file` and `condition` above) point to null-terminated
+ // strings since they are `CStr`s.
+ // - The function pointer (`format`) points to the proper function.
+ // - The pointers passed will remain valid since they point to `static`s.
+ // - The format string is allowed to be null.
+ // - There are, however, problems with this: first of all, this will end up stopping
+ // the thread, without running destructors. While that is problematic in itself,
+ // it is considered UB to have what is effectively a forced foreign unwind
+ // with `extern "C"` ABI. One could observe the stack that is now gone from
+ // another thread. We should avoid pinning stack variables to prevent library UB,
+ // too. For the moment, given that test failures are reported immediately before the
+ // next test runs, that test failures should be fixed and that KUnit is explicitly
+ // documented as not suitable for production environments, we feel it is reasonable.
+ unsafe {
+ $crate::bindings::__kunit_do_failed_assertion(
+ kunit_test,
+ core::ptr::addr_of!(LOCATION.0),
+ $crate::bindings::kunit_assert_type_KUNIT_ASSERTION,
+ core::ptr::addr_of!(ASSERTION.0.assert),
+ Some($crate::bindings::kunit_unary_assert_format),
+ core::ptr::null(),
+ );
+ }
+
+ // SAFETY: FFI call; the `test` pointer is valid because this hidden macro should only
+ // be called by the generated documentation tests which forward the test pointer given
+ // by KUnit.
+ unsafe {
+ $crate::bindings::__kunit_abort(kunit_test);
+ }
+ }
+ };
+}
+
+/// Asserts that two expressions are equal to each other (using [`PartialEq`]).
+///
+/// Public but hidden since it should only be used from generated tests.
+///
+/// Unlike the one in `core`, this one does not panic; instead, it is mapped to the KUnit
+/// facilities. See [`assert!`] for more details.
+#[doc(hidden)]
+#[macro_export]
+macro_rules! kunit_assert_eq {
+ ($name:literal, $file:literal, $diff:expr, $left:expr, $right:expr $(,)?) => {{
+ // For the moment, we just forward to the expression assert because, for binary asserts,
+ // KUnit supports only a few types (e.g. integers).
+ $crate::kunit_assert!($name, $file, $diff, $left == $right);
+ }};
+}
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 85b261209977..3642cadc34b1 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -34,6 +34,8 @@ mod build_assert;
pub mod error;
pub mod init;
pub mod ioctl;
+#[cfg(CONFIG_KUNIT)]
+pub mod kunit;
pub mod prelude;
pub mod print;
mod static_assert;
diff --git a/scripts/.gitignore b/scripts/.gitignore
index 6e9ce6720a05..3dbb8bb2457b 100644
--- a/scripts/.gitignore
+++ b/scripts/.gitignore
@@ -5,6 +5,8 @@
/kallsyms
/module.lds
/recordmcount
+/rustdoc_test_builder
+/rustdoc_test_gen
/sign-file
/sorttable
/target.json
diff --git a/scripts/Makefile b/scripts/Makefile
index 32b6ba722728..576cf64be667 100644
--- a/scripts/Makefile
+++ b/scripts/Makefile
@@ -9,6 +9,8 @@ hostprogs-always-$(CONFIG_BUILDTIME_TABLE_SORT) += sorttable
hostprogs-always-$(CONFIG_ASN1) += asn1_compiler
hostprogs-always-$(CONFIG_MODULE_SIG_FORMAT) += sign-file
hostprogs-always-$(CONFIG_SYSTEM_EXTRA_CERTIFICATE) += insert-sys-cert
+hostprogs-always-$(CONFIG_RUST_KERNEL_DOCTESTS) += rustdoc_test_builder
+hostprogs-always-$(CONFIG_RUST_KERNEL_DOCTESTS) += rustdoc_test_gen
always-$(CONFIG_RUST) += target.json
filechk_rust_target = $< < include/config/auto.conf
@@ -18,6 +20,8 @@ $(obj)/target.json: scripts/generate_rust_target include/config/auto.conf FORCE
hostprogs += generate_rust_target
generate_rust_target-rust := y
+rustdoc_test_builder-rust := y
+rustdoc_test_gen-rust := y
HOSTCFLAGS_sorttable.o = -I$(srctree)/tools/include
HOSTLDLIBS_sorttable = -lpthread
diff --git a/scripts/rustdoc_test_builder.rs b/scripts/rustdoc_test_builder.rs
new file mode 100644
index 000000000000..e5894652f12c
--- /dev/null
+++ b/scripts/rustdoc_test_builder.rs
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Test builder for `rustdoc`-generated tests.
+//!
+//! This script is a hack to extract the test from `rustdoc`'s output. Ideally, `rustdoc` would
+//! have an option to generate this information instead, e.g. as JSON output.
+//!
+//! The `rustdoc`-generated test names look like `{file}_{line}_{number}`, e.g.
+//! `...path_rust_kernel_sync_arc_rs_42_0`. `number` is the "test number", needed in cases like
+//! a macro that expands into items with doctests is invoked several times within the same line.
+//!
+//! However, since these names are used for bisection in CI, the line number makes it not stable
+//! at all. In the future, we would like `rustdoc` to give us the Rust item path associated with
+//! the test, plus a "test number" (for cases with several examples per item) and generate a name
+//! from that. For the moment, we generate ourselves a new name, `{file}_{number}` instead, in
+//! the `gen` script (done there since we need to be aware of all the tests in a given file).
+
+use std::io::Read;
+
+fn main() {
+ let mut stdin = std::io::stdin().lock();
+ let mut body = String::new();
+ stdin.read_to_string(&mut body).unwrap();
+
+ // Find the generated function name looking for the inner function inside `main()`.
+ //
+ // The line we are looking for looks like one of the following:
+ //
+ // ```
+ // fn main() { #[allow(non_snake_case)] fn _doctest_main_rust_kernel_file_rs_28_0() {
+ // fn main() { #[allow(non_snake_case)] fn _doctest_main_rust_kernel_file_rs_37_0() -> Result<(), impl core::fmt::Debug> {
+ // ```
+ //
+ // It should be unlikely that doctest code matches such lines (when code is formatted properly).
+ let rustdoc_function_name = body
+ .lines()
+ .find_map(|line| {
+ Some(
+ line.split_once("fn main() {")?
+ .1
+ .split_once("fn ")?
+ .1
+ .split_once("()")?
+ .0,
+ )
+ .filter(|x| x.chars().all(|c| c.is_alphanumeric() || c == '_'))
+ })
+ .expect("No test function found in `rustdoc`'s output.");
+
+ // Qualify `Result` to avoid the collision with our own `Result` coming from the prelude.
+ let body = body.replace(
+ &format!("{rustdoc_function_name}() -> Result<(), impl core::fmt::Debug> {{"),
+ &format!("{rustdoc_function_name}() -> core::result::Result<(), impl core::fmt::Debug> {{"),
+ );
+
+ // For tests that get generated with `Result`, like above, `rustdoc` generates an `unwrap()` on
+ // the return value to check there were no returned errors. Instead, we use our assert macro
+ // since we want to just fail the test, not panic the kernel.
+ //
+ // We save the result in a variable so that the failed assertion message looks nicer.
+ let body = body.replace(
+ &format!("}} {rustdoc_function_name}().unwrap() }}"),
+ &format!("}} let test_return_value = {rustdoc_function_name}(); assert!(test_return_value.is_ok()); }}"),
+ );
+
+ // Figure out a smaller test name based on the generated function name.
+ let name = rustdoc_function_name.split_once("_rust_kernel_").unwrap().1;
+
+ let path = format!("rust/test/doctests/kernel/{name}");
+
+ std::fs::write(path, body.as_bytes()).unwrap();
+}
diff --git a/scripts/rustdoc_test_gen.rs b/scripts/rustdoc_test_gen.rs
new file mode 100644
index 000000000000..5ebd42ae4a3f
--- /dev/null
+++ b/scripts/rustdoc_test_gen.rs
@@ -0,0 +1,260 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Generates KUnit tests from saved `rustdoc`-generated tests.
+//!
+//! KUnit passes a context (`struct kunit *`) to each test, which should be forwarded to the other
+//! KUnit functions and macros.
+//!
+//! However, we want to keep this as an implementation detail because:
+//!
+//! - Test code should not care about the implementation.
+//!
+//! - Documentation looks worse if it needs to carry extra details unrelated to the piece
+//! being described.
+//!
+//! - Test code should be able to define functions and call them, without having to carry
+//! the context.
+//!
+//! - Later on, we may want to be able to test non-kernel code (e.g. `core`, `alloc` or
+//! third-party crates) which likely use the standard library `assert*!` macros.
+//!
+//! For this reason, instead of the passed context, `kunit_get_current_test()` is used instead
+//! (i.e. `current->kunit_test`).
+//!
+//! Note that this means other threads/tasks potentially spawned by a given test, if failing, will
+//! report the failure in the kernel log but will not fail the actual test. Saving the pointer in
+//! e.g. a `static` per test does not fully solve the issue either, because currently KUnit does
+//! not support assertions (only expectations) from other tasks. Thus leave that feature for
+//! the future, which simplifies the code here too. We could also simply not allow `assert`s in
+//! other tasks, but that seems overly constraining, and we do want to support them, eventually.
+
+use std::{
+ fs,
+ fs::File,
+ io::{BufWriter, Read, Write},
+ path::{Path, PathBuf},
+};
+
+/// Find the real path to the original file based on the `file` portion of the test name.
+///
+/// `rustdoc` generated `file`s look like `sync_locked_by_rs`. Underscores (except the last one)
+/// may represent an actual underscore in a directory/file, or a path separator. Thus the actual
+/// file might be `sync_locked_by.rs`, `sync/locked_by.rs`, `sync_locked/by.rs` or
+/// `sync/locked/by.rs`. This function walks the file system to determine which is the real one.
+///
+/// This does require that ambiguities do not exist, but that seems fair, especially since this is
+/// all supposed to be temporary until `rustdoc` gives us proper metadata to build this. If such
+/// ambiguities are detected, they are diagnosed and the script panics.
+fn find_real_path<'a>(srctree: &Path, valid_paths: &'a mut Vec<PathBuf>, file: &str) -> &'a str {
+ valid_paths.clear();
+
+ let potential_components: Vec<&str> = file.strip_suffix("_rs").unwrap().split('_').collect();
+
+ find_candidates(srctree, valid_paths, Path::new(""), &potential_components);
+ fn find_candidates(
+ srctree: &Path,
+ valid_paths: &mut Vec<PathBuf>,
+ prefix: &Path,
+ potential_components: &[&str],
+ ) {
+ // The base case: check whether all the potential components left, joined by underscores,
+ // is a file.
+ let joined_potential_components = potential_components.join("_") + ".rs";
+ if srctree
+ .join("rust/kernel")
+ .join(prefix)
+ .join(&joined_potential_components)
+ .is_file()
+ {
+ // Avoid `srctree` here in order to keep paths relative to it in the KTAP output.
+ valid_paths.push(
+ Path::new("rust/kernel")
+ .join(prefix)
+ .join(joined_potential_components),
+ );
+ }
+
+ // In addition, check whether each component prefix, joined by underscores, is a directory.
+ // If not, there is no need to check for combinations with that prefix.
+ for i in 1..potential_components.len() {
+ let (components_prefix, components_rest) = potential_components.split_at(i);
+ let prefix = prefix.join(components_prefix.join("_"));
+ if srctree.join("rust/kernel").join(&prefix).is_dir() {
+ find_candidates(srctree, valid_paths, &prefix, components_rest);
+ }
+ }
+ }
+
+ assert!(
+ valid_paths.len() > 0,
+ "No path candidates found. This is likely a bug in the build system, or some files went \
+ away while compiling."
+ );
+
+ if valid_paths.len() > 1 {
+ eprintln!("Several path candidates found:");
+ for path in valid_paths {
+ eprintln!(" {path:?}");
+ }
+ panic!(
+ "Several path candidates found, please resolve the ambiguity by renaming a file or \
+ folder."
+ );
+ }
+
+ valid_paths[0].to_str().unwrap()
+}
+
+fn main() {
+ let srctree = std::env::var("srctree").unwrap();
+ let srctree = Path::new(&srctree);
+
+ let mut paths = fs::read_dir("rust/test/doctests/kernel")
+ .unwrap()
+ .map(|entry| entry.unwrap().path())
+ .collect::<Vec<_>>();
+
+ // Sort paths.
+ paths.sort();
+
+ let mut rust_tests = String::new();
+ let mut c_test_declarations = String::new();
+ let mut c_test_cases = String::new();
+ let mut body = String::new();
+ let mut last_file = String::new();
+ let mut number = 0;
+ let mut valid_paths: Vec<PathBuf> = Vec::new();
+ let mut real_path: &str = "";
+ for path in paths {
+ // The `name` follows the `{file}_{line}_{number}` pattern (see description in
+ // `scripts/rustdoc_test_builder.rs`). Discard the `number`.
+ let name = path.file_name().unwrap().to_str().unwrap().to_string();
+
+ // Extract the `file` and the `line`, discarding the `number`.
+ let (file, line) = name.rsplit_once('_').unwrap().0.rsplit_once('_').unwrap();
+
+ // Generate an ID sequence ("test number") for each one in the file.
+ if file == last_file {
+ number += 1;
+ } else {
+ number = 0;
+ last_file = file.to_string();
+
+ // Figure out the real path, only once per file.
+ real_path = find_real_path(srctree, &mut valid_paths, file);
+ }
+
+ // Generate a KUnit name (i.e. test name and C symbol) for this test.
+ //
+ // We avoid the line number, like `rustdoc` does, to make things slightly more stable for
+ // bisection purposes. However, to aid developers in mapping back what test failed, we will
+ // print a diagnostics line in the KTAP report.
+ let kunit_name = format!("rust_doctest_kernel_{file}_{number}");
+
+ // Read the test's text contents to dump it below.
+ body.clear();
+ File::open(path).unwrap().read_to_string(&mut body).unwrap();
+
+ // Calculate how many lines before `main` function (including the `main` function line).
+ let body_offset = body
+ .lines()
+ .take_while(|line| !line.contains("fn main() {"))
+ .count()
+ + 1;
+
+ use std::fmt::Write;
+ write!(
+ rust_tests,
+ r#"/// Generated `{name}` KUnit test case from a Rust documentation test.
+#[no_mangle]
+pub extern "C" fn {kunit_name}(__kunit_test: *mut kernel::bindings::kunit) {{
+ /// Overrides the usual [`assert!`] macro with one that calls KUnit instead.
+ #[allow(unused)]
+ macro_rules! assert {{
+ ($cond:expr $(,)?) => {{{{
+ kernel::kunit_assert!("{kunit_name}", "{real_path}", __DOCTEST_ANCHOR - {line}, $cond);
+ }}}}
+ }}
+
+ /// Overrides the usual [`assert_eq!`] macro with one that calls KUnit instead.
+ #[allow(unused)]
+ macro_rules! assert_eq {{
+ ($left:expr, $right:expr $(,)?) => {{{{
+ kernel::kunit_assert_eq!("{kunit_name}", "{real_path}", __DOCTEST_ANCHOR - {line}, $left, $right);
+ }}}}
+ }}
+
+ // Many tests need the prelude, so provide it by default.
+ #[allow(unused)]
+ use kernel::prelude::*;
+
+ // Unconditionally print the location of the original doctest (i.e. rather than the location in
+ // the generated file) so that developers can easily map the test back to the source code.
+ //
+ // This information is also printed when assertions fail, but this helps in the successful cases
+ // when the user is running KUnit manually, or when passing `--raw_output` to `kunit.py`.
+ //
+ // 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"));
+
+ /// The anchor where the test code body starts.
+ #[allow(unused)]
+ static __DOCTEST_ANCHOR: i32 = core::line!() as i32 + {body_offset} + 1;
+ {{
+ {body}
+ main();
+ }}
+}}
+
+"#
+ )
+ .unwrap();
+
+ write!(c_test_declarations, "void {kunit_name}(struct kunit *);\n").unwrap();
+ write!(c_test_cases, " KUNIT_CASE({kunit_name}),\n").unwrap();
+ }
+
+ let rust_tests = rust_tests.trim();
+ let c_test_declarations = c_test_declarations.trim();
+ let c_test_cases = c_test_cases.trim();
+
+ write!(
+ BufWriter::new(File::create("rust/doctests_kernel_generated.rs").unwrap()),
+ r#"//! `kernel` crate documentation tests.
+
+const __LOG_PREFIX: &[u8] = b"rust_doctests_kernel\0";
+
+{rust_tests}
+"#
+ )
+ .unwrap();
+
+ write!(
+ BufWriter::new(File::create("rust/doctests_kernel_generated_kunit.c").unwrap()),
+ r#"/*
+ * `kernel` crate documentation tests.
+ */
+
+#include <kunit/test.h>
+
+{c_test_declarations}
+
+static struct kunit_case test_cases[] = {{
+ {c_test_cases}
+ {{ }}
+}};
+
+static struct kunit_suite test_suite = {{
+ .name = "rust_doctests_kernel",
+ .test_cases = test_cases,
+}};
+
+kunit_test_suite(test_suite);
+
+MODULE_LICENSE("GPL");
+"#
+ )
+ .unwrap();
+}