scx_rustland_core: generate source files in-tree

There is no need to generate source code in a temporary directory with
RustLandBuilder(), we can simply generate code in-tree and exclude the
generated source files from .gitignore.

Having the generated source files in-tree can help to debug potential
build issues (and it also allows to drop the the tempfile crate
dependency).

Signed-off-by: Andrea Righi <andrea.righi@canonical.com>

rust/scx_rustland_core/Cargo.toml

@@ -10,6 +10,7 @@ description = "Framework to implement sched_ext schedulers running in user space
 include = [
     "src/bpf/intf.h",
     "src/bpf/main.bpf.c",
+    "src/bpf.rs",
 ]
 
 [dependencies]
@@ -17,7 +18,6 @@ anyhow = "1.0"
 libbpf-rs = "0.22.0"
 libc = "0.2.137"
 buddy-alloc = "0.5.1"
-tempfile = "3.10.1"
 scx_utils = { path = "../scx_utils", version = "0.6" }
 
 [build-dependencies]

rust/scx_rustland_core/src/rustland_builder.rs

@@ -5,63 +5,46 @@
 
 use anyhow::Result;
 
-use std::error::Error;
 use std::fs::File;
 use std::io::Write;
-use std::path::{Path, PathBuf};
-
-use tempfile::tempdir;
+use std::path::Path;
 
 use scx_utils::BpfBuilder;
 
 pub struct RustLandBuilder {
     inner_builder: BpfBuilder,
-    temp_dir: tempfile::TempDir,
 }
 
 impl RustLandBuilder {
     pub fn new() -> Result<Self> {
         Ok(Self {
             inner_builder: BpfBuilder::new()?,
-            temp_dir: tempdir()?,
         })
     }
 
-    fn create_temp_file(
-        &mut self,
-        file_name: &str,
-        content: &[u8],
-    ) -> Result<PathBuf, Box<dyn Error>> {
-        let mut temp_file = self.temp_dir.as_ref().to_path_buf();
-        temp_file.push(file_name);
-        let mut file = File::create(&temp_file)?;
-        file.write_all(content)?;
-
-        Ok(temp_file)
-    }
-
-    fn get_bpf_rs_content(&self) -> &'static str {
-        include_str!("bpf.rs")
+    fn create_file(&self, file_name: &str, content: &[u8]) {
+        let path = Path::new(file_name);
+        let mut file = File::create(&path).expect("Unable to create file");
+        file.write_all(content).expect("Unable to write to file");
     }
 
     pub fn build(&mut self) -> Result<()> {
-        // Embed the BPF source files in the crate.
+        // Embed the BPF source files.
         let intf = include_bytes!(concat!(env!("CARGO_MANIFEST_DIR"), "/src/bpf/intf.h"));
         let skel = include_bytes!(concat!(env!("CARGO_MANIFEST_DIR"), "/src/bpf/main.bpf.c"));
+        let bpf = include_bytes!(concat!(env!("CARGO_MANIFEST_DIR"), "/src/bpf.rs"));
 
-        let intf_path = self.create_temp_file("intf.h", intf).unwrap();
-        let skel_path = self.create_temp_file("main.bpf.c", skel).unwrap();
+        // Generate BPF backend code (C).
+        self.create_file("intf.h", intf);
+        self.create_file("main.bpf.c", skel);
 
-        self.inner_builder
-            .enable_intf(intf_path.to_str().unwrap(), "bpf_intf.rs");
-        self.inner_builder
-            .enable_skel(skel_path.to_str().unwrap(), "bpf");
+        self.inner_builder.enable_intf("intf.h", "bpf_intf.rs");
+        self.inner_builder.enable_skel("main.bpf.c", "bpf");
 
-        let content = self.get_bpf_rs_content();
-        let path = Path::new("src/bpf.rs");
-        let mut file = File::create(&path).expect("Unable to create file");
-        file.write_all(content.as_bytes()).expect("Unable to write to file");
+        // Generate user-space BPF connector code (Rust).
+        self.create_file("src/bpf.rs", bpf);
 
+        // Build the scheduler.
         self.inner_builder.build()
     }
 }

scheds/rust/scx_rlfifo/.gitignore

@@ -1,4 +1,6 @@
 src/bpf/.output
+intf.h
+main.bpf.c
 bpf.rs
 Cargo.lock
 target

scheds/rust/scx_rustland/.gitignore

@@ -1,4 +1,6 @@
 src/bpf/.output
+intf.h
+main.bpf.c
 bpf.rs
 Cargo.lock
 target