Use stack-based formatter for debug-printing. (#233)

Signed-off-by: Leon Durrenberger <[email protected]>
Co-authored-by: Melvin Wang <[email protected]>
Co-authored-by: leon-xd <[email protected]>
Co-authored-by: Leon Durrenberger <[email protected]>

Author: 4 people

Cargo.lock

@@ -344,7 +344,7 @@ fn read_registry_key_string_value(
                 return Some(
                     CStr::from_bytes_with_nul(&buffer[..len as usize])
                         .expect(
-                            "RegGetValueA should always return a null terminated string. The read \
+                            "RegGetValueA should always return a null-terminated string. The read \
                              string (REG_SZ) from the registry should not contain any interior \
                              nulls.",
                         )

crates/wdk-build/src/utils.rs

@@ -118,7 +118,7 @@ static TEST_STUBS_TEMPLATE: LazyLock<String> = LazyLock::new(|| {
         r"
 use crate::WDFFUNC;
 
-/// Stubbed version of the symbol that [`WdfFunctions`] links to so that test targets will compile
+/// Stubbed version of the symbol that `WdfFunctions` links to so that test targets will compile
 #[no_mangle]
 pub static mut {WDFFUNCTIONS_SYMBOL_NAME_PLACEHOLDER}: *const WDFFUNC = core::ptr::null();
 ",

crates/wdk-sys/build.rs

@@ -28,7 +28,7 @@ use crate::{DRIVER_OBJECT, NTSTATUS, PCUNICODE_STRING};
     driver_model__driver_type = "UMDF"
 ))]
 #[export_name = "DriverEntry"] // WDF expects a symbol with the name DriverEntry
-pub unsafe extern "system" fn driver_entry_stub(
+pub const unsafe extern "system" fn driver_entry_stub(
     _driver: &mut DRIVER_OBJECT,
     _registry_path: PCUNICODE_STRING,
 ) -> NTSTATUS {

crates/wdk-sys/src/test_stubs.rs

@@ -22,6 +22,7 @@ tracing-subscriber = { workspace = true, features = ["env-filter"] }
 wdk-build.workspace = true
 
 [dependencies]
+cfg-if.workspace = true
 wdk-sys.workspace = true
 
 [dev-dependencies]

crates/wdk/Cargo.toml

@@ -5,7 +5,10 @@
 //! built on top of the raw FFI bindings provided by [`wdk-sys`], and provides a
 //! safe, idiomatic rust interface to the WDK.
 
-#![no_std]
+#![cfg_attr(
+    any(driver_model__driver_type = "WDM", driver_model__driver_type = "KMDF"),
+    no_std
+)]
 
 #[cfg(any(
     all(

crates/wdk/src/lib.rs

@@ -13,7 +13,11 @@ extern crate alloc;
 #[cfg(not(test))]
 extern crate wdk_panic;
 
-use alloc::{ffi::CString, slice, string::String};
+use alloc::{
+    ffi::CString,
+    slice,
+    string::String,
+};
 
 use wdk::println;
 #[cfg(not(test))]
@@ -56,9 +60,9 @@ pub unsafe extern "system" fn driver_entry(
     let string = CString::new("Hello World!\n").unwrap();
 
     // SAFETY: This is safe because `string` is a valid pointer to a null-terminated
-    // string
+    // string (`CString` guarantees null-termination)
     unsafe {
-        DbgPrint(string.as_ptr());
+        DbgPrint(c"%s".as_ptr().cast(), string.as_ptr());
     }
 
     driver.DriverUnload = Some(driver_exit);

crates/wdk/src/print.rs

@@ -42,7 +42,7 @@ pub unsafe extern "system" fn driver_entry(
     let string = CString::new("Hello World!\n").unwrap();
 
     // SAFETY: This is safe because `string` is a valid pointer to a null-terminated
-    // string
+    // string (`CString` guarantees null-termination)
     unsafe {
         OutputDebugStringA(string.as_ptr());
     }

examples/sample-kmdf-driver/Cargo.lock

@@ -37,8 +37,11 @@ pub unsafe extern "system" fn driver_entry(
 ) -> NTSTATUS {
     // This is an example of directly using DbgPrint binding to print
     let string = CString::new("Hello World!\n").unwrap();
+
+    // SAFETY: This is safe because `string` is a valid pointer to a null-terminated
+    // string (`CString` guarantees null-termination)
     unsafe {
-        DbgPrint(string.as_ptr());
+        DbgPrint(c"%s".as_ptr().cast(), string.as_ptr());
     }
 
     driver.DriverUnload = Some(driver_exit);