Statically link to the Rust library

.envrc

@@ -0,0 +1 @@
+use nix

Makefile

@@ -0,0 +1,36 @@
+RUSTFLAGS := RUSTFLAGS='-C link-arg=-s'
+BUILD_CMD := cargo build --release
+
+.PHONY: all clean clean-all
+
+golib: rustlib header
+	go build
+
+rustlib: libzkgroup-amd64 libzkgroup-arm64 libzkgroup-armhf
+
+libzkgroup-amd64:
+	cd lib/zkgroup && \
+	$(RUSTFLAGS) $(BUILD_CMD)
+	cp lib/zkgroup/target/release/libzkgroup.a lib/libzkgroup_linux_amd64.a
+
+libzkgroup-arm64:
+	cd lib/zkgroup && \
+	$(RUSTFLAGS) CARGO_TARGET_AARCH64_UNKNOWN_LINUX_GNU_LINKER=aarch64-unknown-linux-gnu-gcc $(BUILD_CMD) --target=aarch64-unknown-linux-gnu
+	cp lib/zkgroup/target/aarch64-unknown-linux-gnu/release/libzkgroup.a lib/libzkgroup_linux_arm64.a
+
+libzkgroup-armhf:
+	cd lib/zkgroup && \
+	$(RUSTFLAGS) CARGO_TARGET_ARMV7_UNKNOWN_LINUX_GNUEABIHF_LINKER=armv7l-unknown-linux-gnueabihf-gcc $(BUILD_CMD) --target=armv7-unknown-linux-gnueabihf
+	cp lib/zkgroup/target/armv7-unknown-linux-gnueabihf/release/libzkgroup.a lib/libzkgroup_linux_armhf.a
+
+header:
+	cbindgen --lang c lib/zkgroup/rust -o lib/zkgroup.h
+
+clean:
+	go clean
+	cd lib/zkgroup && \
+	cargo clean
+
+clean-all: clean
+	rm lib/*.a
+	rm lib/*.h

README.md

@@ -4,33 +4,62 @@ Go library for the Signal Private Group System.
 
 See [github.com/signalapp/zkgroup](https://github.com/signalapp/zkgroup).
 
-# build zkgroup
+## Build the Rust library
 
-- checkout git submodules
--
+### Build environment
 
-# cross compile
+### With [Nix](https://nixos.org/)
 
-`cargo install cross`
-`cd lib/zkgroup/`
+Simply enter the Nix shell:
 
-## linux aarch64
+    $ nix-shell
 
+Alternatively, if you are also using [direnv](https://direnv.net/), you can
+allow the `.envrc` to enter automatically the Nix shell whenever you enter the
+project:
 
-`cross build --target aarch64-unknown-linux-gnu`
+    $ direnv allow
 
-`cp target/aarch64-unknown-linux-gnu/debug/libzkgroup.so ../libzkgroup_linux_aarch64.so`
+### Without Nix
 
+In order to build the Rust library for all three supported platform, you’ll
+first need [Rustup](https://rustup.rs/).
 
-## linux,armhf 
+Then, install the stable Rust toolchain:
 
-`cross build --target armv7-unknown-linux-gnueabihf`
-`cp target/armv7-unknown-linux-gnueabihf/debug/libzkgroup.so ../libzkgroup_linux_armhf.so`
+    $ rustup install stable
 
-or install  arm-linux-gnueabihf-gcc and 
+Install the targets for the mobile platforms:
 
-```
-export CARGO_TARGET_ARMV7_UNKNOWN_LINUX_GNUEABIHF_LINKER=/usr/bin/arm-linux-gnueabihf-gcc
+    $ rustup target add aarch64-unknown-linux-gnu
+    $ rustup target add armv7-unknown-linux-gnueabihf
 
-cargo build --target armv7-unknown-linux-gnueabihf --release --verbose
-```
+Install C compilers for these targets. Instructions depend on your distribution,
+but you should have `aarch64-unknown-linux-gnu-gcc` and
+`armv7l-unknown-linux-gnueabihf-gcc` in your path.
+
+Install `cbindgen` to generate the C header for the Rust FFI:
+
+    $ cargo install cbindgen
+
+### Build instructions
+
+1. Fetch the submodule, if not already done:
+
+        $ git submodule init
+        $ git submodule update
+
+2. Build the library:
+
+        $ make
+
+This will build the Rust library into a static library for `amd64`, `arm64` and
+`armhf` on Linux, put them in `lib/` and generate `lib/zkgroup.h`.
+
+3. Clean the Rust articafcts:
+
+        $ make clean
+
+You can also remove the generated files by running:
+
+        $ make clean-all

auth_credential.go

@@ -1,9 +1,9 @@
 package zkgroup
 
 /*
-#cgo linux,amd64 LDFLAGS: -L${SRCDIR}/lib '-Wl,-rpath,$$ORIGIN/' -lzkgroup_linux_amd64
-#cgo linux,arm64 LDFLAGS: -L${SRCDIR}/lib '-Wl,-rpath,$$ORIGIN/' -lzkgroup_linux_arm64
-#cgo linux,arm LDFLAGS: -L${SRCDIR}/lib '-Wl,-rpath,$$ORIGIN/' -lzkgroup_linux_armhf
+#cgo linux,amd64 LDFLAGS: -L${SRCDIR}/lib -ldl -lzkgroup_linux_amd64
+#cgo linux,arm64 LDFLAGS: -L${SRCDIR}/lib -ldl -lzkgroup_linux_arm64
+#cgo linux,arm LDFLAGS: -L${SRCDIR}/lib -ldl -lzkgroup_linux_armhf
 
 #include "lib/zkgroup.h"
 */

client.go

@@ -1,9 +1,9 @@
 package zkgroup
 
 /*
-#cgo linux,amd64 LDFLAGS: -L${SRCDIR}/lib '-Wl,-rpath,$$ORIGIN/' -lzkgroup_linux_amd64
-#cgo linux,arm64 LDFLAGS: -L${SRCDIR}/lib '-Wl,-rpath,$$ORIGIN/' -lzkgroup_linux_arm64
-#cgo linux,arm LDFLAGS: -L${SRCDIR}/lib '-Wl,-rpath,$$ORIGIN/' -lzkgroup_linux_armhf
+#cgo linux,amd64 LDFLAGS: -L${SRCDIR}/lib -ldl -lzkgroup_linux_amd64
+#cgo linux,arm64 LDFLAGS: -L${SRCDIR}/lib -ldl -lzkgroup_linux_arm64
+#cgo linux,arm LDFLAGS: -L${SRCDIR}/lib -ldl -lzkgroup_linux_armhf
 
 #include "lib/zkgroup.h"
 */

error.go

@@ -1,9 +1,9 @@
 package zkgroup
 
 /*
-#cgo linux,amd64 LDFLAGS: -L${SRCDIR}/lib '-Wl,-rpath,$$ORIGIN/' -lzkgroup_linux_amd64
-#cgo linux,arm64 LDFLAGS: -L${SRCDIR}/lib '-Wl,-rpath,$$ORIGIN/' -lzkgroup_linux_arm64
-#cgo linux,arm LDFLAGS: -L${SRCDIR}/lib '-Wl,-rpath,$$ORIGIN/' -lzkgroup_linux_armhf
+#cgo linux,amd64 LDFLAGS: -L${SRCDIR}/lib -ldl -lzkgroup_linux_amd64
+#cgo linux,arm64 LDFLAGS: -L${SRCDIR}/lib -ldl -lzkgroup_linux_arm64
+#cgo linux,arm LDFLAGS: -L${SRCDIR}/lib -ldl -lzkgroup_linux_armhf
 
 #include "lib/zkgroup.h"
 */

group.go

@@ -1,9 +1,9 @@
 package zkgroup
 
 /*
-#cgo linux,amd64 LDFLAGS: -L${SRCDIR}/lib '-Wl,-rpath,$$ORIGIN/' -lzkgroup_linux_amd64
-#cgo linux,arm64 LDFLAGS: -L${SRCDIR}/lib '-Wl,-rpath,$$ORIGIN/' -lzkgroup_linux_arm64
-#cgo linux,arm LDFLAGS: -L${SRCDIR}/lib '-Wl,-rpath,$$ORIGIN/' -lzkgroup_linux_armhf
+#cgo linux,amd64 LDFLAGS: -L${SRCDIR}/lib -ldl -lzkgroup_linux_amd64
+#cgo linux,arm64 LDFLAGS: -L${SRCDIR}/lib -ldl -lzkgroup_linux_arm64
+#cgo linux,arm LDFLAGS: -L${SRCDIR}/lib -ldl -lzkgroup_linux_armhf
 
 #include "lib/zkgroup.h"
 */