library is configurable now

.cargo/config.toml

@@ -0,0 +1,4 @@
+[env]
+# This is set for this repository so it does not always have to be set in the command line.
+# It is required for building libcsp-rust.
+CSP_CONFIG_DIR = { value = "examples", relative = true }

examples/autoconfig.rs

@@ -0,0 +1,7 @@
+const CSP_CONN_RXQUEUE_LEN: usize = 16
+const CSP_QFIFO_LEN: usize = 16
+const CSP_PORT_MAX_BIND: usize = 16
+const CSP_CONN_MAX: usize = 8
+const CSP_BUFFER_SIZE: usize = 256
+const CSP_RDP_MAX_WINDOW: usize = 5
+const CSP_RTABLE_SIZE: usize = 10

examples/build.rs

@@ -4,8 +4,18 @@ use libcsp_cargo_build::Builder;
 
 fn main() {
     let out_dir = env::var("OUT_DIR").unwrap_or_default();
-
+    let manifest_dir = env::var("CARGO_MANIFEST_DIR").unwrap_or_default();
     let libcsp_path = "../lib/libcsp";
-    let mut csp_builder = Builder::new(PathBuf::from(libcsp_path), PathBuf::from(out_dir));
+    let mut csp_builder = Builder::new(PathBuf::from(libcsp_path), PathBuf::from(&out_dir));
+    let update_autoconf = match env::var("UPDATE_CSP_AUTOCONF") {
+        Ok(update_autoconf) => update_autoconf == "1",
+        Err(_e) => false,
+    };
+    if update_autoconf {
+        csp_builder
+            .generate_autoconf_rust_file(PathBuf::from(&manifest_dir))
+            .expect("generating autoconfig.rs failed");
+        println!("cargo:warning=autoconfig.rs updated");
+    }
     csp_builder.compile().expect("compiling libcsp failed");
 }

libcsp-cargo-build/src/lib.rs

@@ -199,12 +199,15 @@ impl Builder {
         self.build.include(&autoconf_dir);
         autoconf_dir.push("csp");
         std::fs::create_dir_all(&autoconf_dir)?;
-        generate_autoconf_file(autoconf_dir, &self.cfg)
+        generate_autoconf_header_file(autoconf_dir, &self.cfg)
+    }
+
+    pub fn generate_autoconf_rust_file(&self, out_dir: PathBuf) -> io::Result<()> {
+        generate_autoconf_rust_file(out_dir, &self.cfg)
     }
 }
 
-pub fn generate_autoconf_file(out_dir: PathBuf, cfg: &Config) -> io::Result<()> {
-    // panic!("cargo:warning=outdir for autoconf file: {:?}", out_dir);
+pub fn generate_autoconf_header_file(out_dir: PathBuf, cfg: &Config) -> io::Result<()> {
     let mut autoconf_file_string = String::new();
     #[cfg(unix)]
     autoconf_file_string.push_str("#define CSP_POSIX 1\n");
@@ -307,6 +310,49 @@ pub fn generate_autoconf_file(out_dir: PathBuf, cfg: &Config) -> io::Result<()>
     Ok(())
 }
 
+pub fn generate_autoconf_rust_file(out_dir: PathBuf, cfg: &Config) -> io::Result<()> {
+    let mut autoconf_file_string = String::new();
+    autoconf_file_string.push_str(&format!(
+        "const {}: usize = {}\n",
+        autoconf::CFG_CONN_RXQUEUE_LEN,
+        cfg.conn_rx_queue_len
+    ));
+    autoconf_file_string.push_str(&format!(
+        "const {}: usize = {}\n",
+        autoconf::CFG_QFIFO_LEN,
+        cfg.qfifo_len
+    ));
+    autoconf_file_string.push_str(&format!(
+        "const {}: usize = {}\n",
+        autoconf::CFG_PORT_MAX_BIND,
+        cfg.port_max_bind
+    ));
+    autoconf_file_string.push_str(&format!(
+        "const {}: usize = {}\n",
+        autoconf::CFG_CONN_MAX,
+        cfg.conn_max
+    ));
+    autoconf_file_string.push_str(&format!(
+        "const {}: usize = {}\n",
+        autoconf::CFG_BUFFER_SIZE,
+        cfg.buffer_size
+    ));
+    autoconf_file_string.push_str(&format!(
+        "const {}: usize = {}\n",
+        autoconf::CFG_RDP_MAX_WINDOW,
+        cfg.rdp_max_window
+    ));
+    autoconf_file_string.push_str(&format!(
+        "const {}: usize = {}\n",
+        autoconf::CFG_RTABLE_SIZE,
+        cfg.rtable_size
+    ));
+    let out_file = out_dir.join("autoconfig.rs");
+    let mut file = std::fs::File::create(out_file)?;
+    file.write_all(autoconf_file_string.as_bytes())?;
+    Ok(())
+}
+
 #[cfg(test)]
 mod tests {
     // TODO: Unittest autoconf generator.

libcsp-rust/build.rs

@@ -1,3 +1,29 @@
+use std::{env, path::PathBuf};
+
+pub const ENV_KEY_CSP_CONFIG_DIR: &str = "CSP_CONFIG_DIR";
+
 fn main() {
-    println!("cargo:rustc-link-lib=csp")
+    println!("cargo:rustc-link-lib=csp");
+
+    let out_path = env::var("OUT_DIR").unwrap();
+    let csp_conf_dir = match env::var("CSP_CONFIG_DIR") {
+        Ok(conf_path) => conf_path,
+        Err(_e) => {
+            println!("cargo:warning=CSP_CONFIG_DIR not set, using CARGO_MANIFEST_DIR to search for autoconfig.rs");
+            env::var("CARGO_MANIFEST_DIR").expect("CARGO_MANIFEST_DIR not set")
+        }
+    };
+    println!("cargo:warning=CSP_CONFIG_DIR={}", csp_conf_dir);
+    let mut csp_conf_path = PathBuf::new();
+    csp_conf_path.push(csp_conf_dir);
+    csp_conf_path.push("autoconfig.rs");
+    if !csp_conf_path.exists() {
+        panic!(
+            "autoconfig.rs not found at {:?}, is required for library build",
+            csp_conf_path
+        );
+    }
+    let out_path_full = PathBuf::from(&out_path).join("autoconfig.rs");
+    std::fs::copy(&csp_conf_path, out_path_full).expect("failed to copy autoconfig.rs to OUT_DIR");
+    println!("cargo::rerun-if-changed={:?}", &csp_conf_path);
 }

libcsp-rust/src/config.rs

@@ -0,0 +1,3 @@
+/// This environbment variable should be set by the user. If it is not set, the library will
+/// try to find an autoconfig.rs file inside the CARGO_TARGET_DIR directory.
+pub const ENV_KEY_CSP_CONFIG_DIR: &str = "CSP_CONFIG_DIR";

libcsp-rust/src/ffi.rs

@@ -2,10 +2,10 @@
 #![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
 
-// These constants come from the autoconfig file, which is supposed to be configurable..
-// How do we deal with this? Rust libraries are not supposed to be configured like this.
-pub const CSP_BUFFER_SIZE: usize = 256;
-pub const CSP_CONN_RXQUEUE_LEN: usize = 16;
+// This file will be created by the build script by copying a user-provided file to the output
+// directory. It contains important compile time constants. Compilation of the library is not
+// possible without these constants.
+include!(concat!(env!("OUT_DIR"), "/autoconfig.rs"));
 
 #[repr(C)]
 #[derive(Debug, Copy, Clone)]

libcsp-rust/src/lib.rs

@@ -6,6 +6,8 @@ extern crate alloc;
 extern crate std;
 
 pub mod ffi;
+pub mod config;
+
 use core::time::Duration;
 
 use num_enum::{IntoPrimitive, TryFromPrimitive};

libcsp-rust/templates/autoconfig.rs

@@ -0,0 +1,8 @@
+pub const CSP_CONN_RXQUEUE_LEN: usize = 16;
+pub const CSP_QFIFO_LEN: usize = 15;
+pub const CSP_PORT_MAX_BIND: usize = 16;
+pub const CSP_CONN_MAX: usize = 8;
+pub const CSP_BUFFER_SIZE: usize = 256;
+pub const CSP_BUFFER_COUNT: usize = 15;
+pub const CSP_RDP_MAX_WINDOW: usize = 5;
+pub const CSP_RTABLE_SIZE: usize = 10;