Merge pull request #211 from tranzystorek-io/link-system-deps

Allow finding and linking system deps

README.md

@@ -50,6 +50,13 @@ Minimal builds
 The default-on `kems` and `sigs` features turn on all supported KEMs and signature schemes. If you want a smaller build, turn off these default features and opt-in to individual algorithms.
 Note that if you specify `default-features = false`, you may also want to re-include the `oqs-sys/openssl` feature.
 
+Vendored `liboqs`
+-----------------
+
+By default `oqs-sys` attempts to find a system-provided version of `liboqs` and build against it,
+falling back to vendored from-source build otherwise.
+You can opt into forcing the vendored build by enabling the `vendored` feature.
+
 Serde support
 -------------
 

oqs-sys/Cargo.toml

@@ -18,6 +18,7 @@ include = ["README.md", "build.rs", "src/**", "liboqs/.CMake/**", "liboqs/src/**
 libc = "0.2"
 
 [build-dependencies]
+pkg-config = "0.3"
 cmake = "0.1"
 bindgen = "0.68"
 build-deps = "0.1"
@@ -27,6 +28,7 @@ default = ["openssl", "kems", "sigs"]
 openssl = []
 docs = []
 non_portable = []
+vendored = []
 # algorithms: KEMs
 kems = ["classic_mceliece", "frodokem", "hqc", "kyber", "ntruprime"]
 bike = []  # BIKE is enabled by build.rs on non-windows targets

oqs-sys/build.rs

@@ -1,7 +1,7 @@
-use std::path::Path;
+use std::path::{Path, PathBuf};
 
-fn generate_bindings(outdir: &Path, headerfile: &str, filter: &str) {
-    let includedir = outdir.join("build").join("include");
+fn generate_bindings(includedir: &Path, headerfile: &str, filter: &str) {
+    let out_path = PathBuf::from(std::env::var("OUT_DIR").unwrap());
     bindgen::Builder::default()
         .clang_arg(format!("-I{}", includedir.display()))
         .header(
@@ -31,14 +31,11 @@ fn generate_bindings(outdir: &Path, headerfile: &str, filter: &str) {
         .generate()
         // Unwrap the Result and panic on failure.
         .expect("Unable to generate bindings")
-        .write_to_file(outdir.join(format!("{headerfile}_bindings.rs")))
+        .write_to_file(out_path.join(format!("{headerfile}_bindings.rs")))
         .expect("Couldn't write bindings!");
 }
 
-fn main() {
-    // Check if clang is available before compiling anything.
-    bindgen::clang_version();
-
+fn build_from_source() -> PathBuf {
     let mut config = cmake::Config::new("liboqs");
     config.profile("Release");
     config.define("OQS_BUILD_ONLY_LIB", "Yes");
@@ -117,7 +114,50 @@ fn main() {
     }
     println!("cargo:rustc-link-search=native={}", libdir.display());
 
-    let gen_bindings = |file, filter| generate_bindings(&outdir, file, filter);
+    outdir
+}
+
+fn includedir_from_source() -> PathBuf {
+    let outdir = build_from_source();
+    outdir.join("build").join("include")
+}
+
+fn trim_wrapped_patch_version(patch: &str) -> &str {
+    let len = patch.len();
+    if len < 3 {
+        return patch;
+    }
+
+    &patch[..len - 2]
+}
+
+fn probe_includedir() -> PathBuf {
+    if cfg!(feature = "vendored") {
+        return includedir_from_source();
+    }
+
+    let major_version: usize = env!("CARGO_PKG_VERSION_MAJOR").parse().unwrap();
+    let minor_version: usize = env!("CARGO_PKG_VERSION_MINOR").parse().unwrap();
+    let patch_version = env!("CARGO_PKG_VERSION_PATCH");
+    let patch_trimmed = trim_wrapped_patch_version(patch_version);
+    let lower_bound = format!("{}.{}.{}", major_version, minor_version, patch_trimmed);
+    let upper_bound = format!("{}.{}.0", major_version, minor_version + 1);
+    let config = pkg_config::Config::new()
+        .range_version(lower_bound.as_str()..upper_bound.as_str())
+        .probe("liboqs");
+
+    match config {
+        Ok(lib) => lib.include_paths.first().cloned().unwrap(),
+        _ => includedir_from_source(),
+    }
+}
+
+fn main() {
+    // Check if clang is available before compiling anything.
+    bindgen::clang_version();
+
+    let includedir = probe_includedir();
+    let gen_bindings = |file, filter| generate_bindings(&includedir, file, filter);
 
     gen_bindings("common", "OQS_.*");
     gen_bindings("rand", "OQS_(randombytes|RAND)_.*");

oqs/Cargo.toml

@@ -23,6 +23,7 @@ default-features = false
 default = ["oqs-sys/openssl", "kems", "sigs", "std"]
 std = []
 non_portable = ["oqs-sys/non_portable"]
+vendored = ["oqs-sys/vendored"]
 
 # algorithms: KEMs
 kems = ["oqs-sys/kems", "classic_mceliece", "frodokem", "hqc", "kyber", "ntruprime"]