iox-#73 Support cross compile for aarch64

.cargo/config.toml

@@ -1,3 +1,6 @@
 [env]
 RUST_TEST_THREADS = "1"     # prevent running multiple RouDiEnvironments in parallel with `cargo test`
 NEXTEST_TEST_THREADS = "1"  # prevent running multiple RouDiEnvironments in parallel with `cargo nextest run`
+
+[target.aarch64-unknown-linux-gnu]
+linker = "aarch64-linux-gnu-gcc"

README.md

@@ -16,7 +16,8 @@ Safe Rust bindings for [Eclipse iceoryx](https://github.com/eclipse-iceoryx/iceo
     - [How to start RouDi](#how-to-start-roudi)
     - [Run the simple publisher and subscriber example](#run-the-simple-publisher-and-subscriber-example)
 3. [How to write a simple application](#how-to-write-a-simple-application)
-4. [Limitations](#limitations)
+4. [Cross-compiling](#cross-compiling)
+5. [Limitations](#limitations)
 
 ## About
 
@@ -262,6 +263,23 @@ Please have a look at the [examples](https://github.com/eclipse-iceoryx/iceoryx-
 in the repository. It contains additional examples to show how uninitialized samples can be loaned and
 how the `wait_for_samples` method of the `SampleReceiver` can be used to get notified on new samples.
 
+## Cross-Compiling
+
+`iceoryx-sys` uses `cmake` to build `iceoryx` library, which has a dependency `libacl` on Linux. As a result,
+to link to a cross-compiled version of the native `iceoryx`, it's necessary to set several environment variables
+to link against the prebuilt libacl.
+
+To tell the linker lookup libraries from your sysroot, please set the following environment variables, and invoke the build script:
+
+```bash
+# let's take the target aarch64-unknown-linux-gnu for instance
+SYSROOT=/path/to/your/cross/compile/sysroot
+export LDFLAGS="--sysroot $SYSROOT"
+export CARGO_TARGET_AARCH64_UNKNOWN_LINUX_GNU_RUSTFLAGS="-C link-arg=--sysroot=$SYSROOT"
+
+cargo build --target aarch64-unknown-linux-gnu --all-targets
+```
+
 ## Limitations
 
 Currently, only a subset of Eclipse iceoryx v2.0 is supported and some features are missing.

iceoryx-sys/build.rs

@@ -9,10 +9,25 @@ use std::process::Command;
 
 const ICEORYX_VERSION: &str = "v2.0.3";
 
-fn make_and_install(source_dir: &str, build_dir: &str, install_dir: &str) -> std::io::Result<()> {
+fn make_and_install(
+    archive_dir: &str,
+    source_dir: &str,
+    build_dir: &str,
+    install_dir: &str,
+) -> std::io::Result<()> {
     let cmake_install_prefix = format!("-DCMAKE_INSTALL_PREFIX={}", install_dir);
     let cmake_prefix_path = format!("-DCMAKE_PREFIX_PATH={}", install_dir);
 
+    let target = env::var("TARGET").expect("Target");
+    let host = env::var("HOST").expect("Host");
+
+    let extra_cmake_args = if target == host {
+        vec![]
+    } else {
+        let toolchain_cmake_file = format!("{}/toolchain.{}.cmake", archive_dir, target);
+        vec![format!("-DCMAKE_TOOLCHAIN_FILE={}", toolchain_cmake_file)]
+    };
+
     for iceoryx_component in ["iceoryx_hoofs", "iceoryx_posh"] {
         let component_source_dir = format!("{}/{}", source_dir, iceoryx_component);
         let component_build_dir = format!("{}/{}", build_dir, iceoryx_component);
@@ -28,16 +43,17 @@ fn make_and_install(source_dir: &str, build_dir: &str, install_dir: &str) -> std
             ));
         }
 
+        let mut cmake_args = extra_cmake_args.clone();
+        cmake_args.push(format!("-DCMAKE_BUILD_TYPE=Release"));
+        cmake_args.push(format!("-DBUILD_SHARED_LIBS=OFF"));
+        cmake_args.push(format!("-DROUDI_ENVIRONMENT=ON"));
+        cmake_args.push(cmake_prefix_path.clone());
+        cmake_args.push(cmake_install_prefix.clone());
+        cmake_args.push(component_source_dir.clone());
+
         if !Command::new("cmake")
             .current_dir(&component_build_dir)
-            .args([
-                "-DCMAKE_BUILD_TYPE=Release",
-                "-DBUILD_SHARED_LIBS=OFF",
-                "-DROUDI_ENVIRONMENT=ON",
-                &cmake_prefix_path,
-                &cmake_install_prefix,
-                &component_source_dir,
-            ])
+            .args(&cmake_args)
             .status()?
             .success()
         {
@@ -47,9 +63,15 @@ fn make_and_install(source_dir: &str, build_dir: &str, install_dir: &str) -> std
             ));
         }
 
+        let mut cmake_args = Vec::new();
+        cmake_args.push(format!("--build"));
+        cmake_args.push(format!("."));
+        cmake_args.push(format!("--target"));
+        cmake_args.push(format!("install"));
+
         if !Command::new("cmake")
             .current_dir(&component_build_dir)
-            .args(["--build", ".", "--target", "install"])
+            .args(&cmake_args)
             .status()?
             .success()
         {
@@ -110,6 +132,7 @@ fn main() -> std::io::Result<()> {
     extract_archive(&iceoryx_archive_dir, &iceoryx_source_dir, ICEORYX_VERSION)?;
 
     make_and_install(
+        &iceoryx_archive_dir,
         &iceoryx_source_dir,
         &iceoryx_build_dir,
         &iceoryx_install_dir,

iceoryx-sys/iceoryx-cpp/toolchain.aarch64-unknown-linux-gnu.cmake

@@ -0,0 +1,4 @@
+set(CMAKE_SYSTEM_NAME Linux)
+
+set(CMAKE_C_COMPILER aarch64-linux-gnu-gcc)
+set(CMAKE_CXX_COMPILER aarch64-linux-gnu-g++)