Fix tests on other platforms. (#17)

.github/workflows/rust.yml

@@ -37,3 +37,5 @@ jobs:
       - uses: actions/checkout@v3
       - name: Build
         run: cargo build --verbose
+      - name: Run tests
+        run: cargo test --verbose

README.md

@@ -8,15 +8,15 @@
 [![Build Status][actions-badge]][actions-url]
 ![maintenance status][maint-badge]
 
-# Overview
+## Overview
 
 This layer emits tracing events as Windows ETW events or Linux user-mode tracepoints
 (user_events with the [EventHeader](https://github.com/microsoft/LinuxTracepoints/tree/main/libeventheader-tracepoint)
 encoding; requires a Linux 6.4+ kernel).
 
 *Note*: Linux kernels without user_events support will not log any events.
 
-# MSV
+## MSV
 
 Minimum supported Rust version is 1.80 (released July 2024).
 

src/lib.rs

@@ -206,24 +206,29 @@ macro_rules! etw_event {
             }
         );
 
+        #[used]
         static ETW_META: $crate::_details::EventMetadata = $crate::_details::EventMetadata{
             kw: $kw,
             // TODO: Hash the callsite identity at compile time, or get Identifier to implement Ord
             identity: tracing_core::identify_callsite!(&CALLSITE),
             event_tag: $tags as u32
         };
 
+        // These two statics need to be mut to avoid compiler errors about *const EventMetadata not being Sync.
+
         paste! {
             #[cfg(target_os = "linux")]
             #[link_section = "_etw_kw"]
-            #[allow(non_upper_case_globals, dead_code)]
+            #[allow(non_upper_case_globals)]
+            #[used]
             static mut [<ETW_META_PTR $name>]: *const $crate::_details::EventMetadata = &ETW_META;
         }
 
         paste! {
             #[cfg(target_os = "windows")]
-            #[link_section = ".rsdata$zRSETW5"]
-            #[allow(non_upper_case_globals, dead_code)]
+            #[link_section = ".rdata$zRSETW5"]
+            #[allow(non_upper_case_globals)]
+            #[used]
             static mut [<ETW_META_PTR $name>]: *const $crate::_details::EventMetadata = &ETW_META;
         }
 

src/native/etw.rs

@@ -6,12 +6,14 @@ use tracelogging::*;
 use tracelogging_dynamic::EventBuilder;
 use tracing_subscriber::registry::{LookupSpan, SpanRef};
 
+// Items within this .rdata section will be sorted alphabetically, thus the start is named with "0", the end "9", and each metadata "5".
+// If these statics aren't mut then everything will silently fail to work.
 #[allow(non_upper_case_globals)]
-#[link_section = ".rsdata$zRSETW0"]
-pub(crate) static mut _start__etw_kw: usize = usize::from_ne_bytes(*b"RSETW000");
+#[link_section = ".rdata$zRSETW0"]
+pub(crate) static mut _start__etw_kw: usize = 0;
 #[allow(non_upper_case_globals)]
-#[link_section = ".rsdata$zRSETW9"]
-pub(crate) static mut _stop__etw_kw: usize = usize::from_ne_bytes(*b"RSETW999");
+#[link_section = ".rdata$zRSETW9"]
+pub(crate) static mut _stop__etw_kw: usize = 0;
 
 thread_local! {static EBW: std::cell::RefCell<EventBuilder>  = RefCell::new(EventBuilder::new());}
 

src/native/mod.rs

@@ -15,12 +15,6 @@ pub mod noop;
 #[cfg(not(any(target_os = "windows", target_os = "linux")))]
 #[doc(hidden)]
 pub use noop::Provider;
-#[cfg(not(any(target_os = "windows", target_os = "linux")))]
-#[doc(hidden)]
-pub(crate) use noop::_start__etw_kw;
-#[cfg(not(any(target_os = "windows", target_os = "linux")))]
-#[doc(hidden)]
-pub(crate) use noop::_stop__etw_kw;
 
 #[cfg(target_os = "linux")]
 #[doc(hidden)]

src/native/noop.rs

@@ -4,11 +4,6 @@ use tracing_subscriber::registry::{LookupSpan, SpanRef};
 
 use crate::error::EtwError;
 
-#[allow(non_upper_case_globals)]
-pub(crate) static mut _start__etw_kw: usize = 0;
-#[allow(non_upper_case_globals)]
-pub(crate) static mut _stop__etw_kw: usize = 0;
-
 #[doc(hidden)]
 pub struct Provider;
 

src/native/user_events.rs

@@ -6,11 +6,12 @@ use eventheader_dynamic::EventBuilder;
 use std::{cell::RefCell, ops::DerefMut, pin::Pin, sync::Arc, time::SystemTime};
 use tracing_subscriber::registry::{LookupSpan, SpanRef};
 
+// These are automagically generated by the compiler for the start and stop of section _etw_kw
 extern "C" {
     #[link_name = "__start__etw_kw"]
-    pub(crate) static mut _start__etw_kw: usize;
+    pub(crate) static _start__etw_kw: usize;
     #[link_name = "__stop__etw_kw"]
-    pub(crate) static mut _stop__etw_kw: usize;
+    pub(crate) static _stop__etw_kw: usize;
 }
 
 #[link_section = "_etw_kw"]

src/statics.rs

@@ -19,15 +19,17 @@ pub(crate) static GLOBAL_ACTIVITY_SEED: LazyLock<[u8; 16]> = LazyLock::new(|| {
         data
     });
 
-static EVENT_METADATA: LazyLock<Box<[ParsedEventMetadata]>> = LazyLock::new(|| {
+fn process_static_metadata() -> Box<[ParsedEventMetadata]> {
     // The array of pointers are in a mutable section and can be sorted/deduped, but they are pointing to read-only static data
 
     let start =
         &raw const crate::native::_start__etw_kw as *mut *const EventMetadata;
     let stop =
         &raw const crate::native::_stop__etw_kw as *mut *const EventMetadata;
 
-    assert!(!start.is_null());
+    if start.is_null() {
+        return Box::new([]);
+    }
 
     // SAFETY On Windows the start and stop entries are sentry values at the start and end of the linker section.
     // Linux does not need these sentries.
@@ -94,7 +96,13 @@ static EVENT_METADATA: LazyLock<Box<[ParsedEventMetadata]>> = LazyLock::new(|| {
     let mut sorted = vec.into_boxed_slice();
     sorted.sort_unstable_by(|a, b| b.cmp(a));
     sorted
-});
+}
+
+#[cfg(any(target_os = "windows", target_os = "linux"))]
+static EVENT_METADATA: LazyLock<Box<[ParsedEventMetadata]>> = LazyLock::new(process_static_metadata);
+
+#[cfg(not(any(target_os = "windows", target_os = "linux")))]
+static EVENT_METADATA: [ParsedEventMetadata; 0] = [];
 
 impl core::cmp::PartialEq for ParsedEventMetadata {
     fn eq(&self, other: &Self) -> bool {
@@ -212,6 +220,11 @@ mod test {
             sum += event.kw;
         }
 
-        assert_eq!(sum, 55);
+        #[cfg(any(target_os = "windows", target_os = "linux"))]
+        let expected = 55;
+        #[cfg(not(any(target_os = "windows", target_os = "linux")))]
+        let expected = 0;
+
+        assert_eq!(sum, expected);
     }
 }