Adding WASM build using Emscripten

README.md

@@ -66,6 +66,17 @@ C:\repo\build> cmake -D OPENSSL_ROOT_DIR="C:/path/to/openssl-1.1/x86" ..
 C:\repo\build> cmake --build . --config Release
 ```
 
+### WebAssembly (Emscripten / Linux)
+
+It is possible to build WASM code using [emscripten](https://emscripten.org/).
+Consult the manual for how to get it setup. No dependencies are needed as the build
+script will download and compile `openssl` for wasm by itself.
+
+Once your emscripten environment is setup, call `build.sh` with the following flag.
+```sh
+$ ./build.sh em-wasm
+```
+
 ## Install
 
 After the project has been compiled. run `sudo ./install.sh` or the following code if you dont want to use that:

build.sh

@@ -1,7 +1,17 @@
 #!/bin/bash
 
+BASE_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+
 mkdir build 2> /dev/null
 pushd build > /dev/null
-cmake .. $@
+
+# Emscripten WASM build.
+if [ $# -gt 0 ] && [ "$1" = "em-wasm" ]; then
+	shift 1
+	. ${BASE_DIR}/scripts/emscripten.sh $@
+else
+	cmake $@ ..
 	make -B
+fi
+
 popd > /dev/null

scripts/emscripten.sh

@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+
+BASE_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+
+# Build openssl
+. "${BASE_DIR}/emscripten_openssl.sh" "openssl"
+
+#  Configure cmake
+emconfigure cmake \
+      -DCMAKE_BUILD_TYPE=Release \
+	  -DOPENSSL_ROOT_DIR="openssl" \
+	  -DOPENSSL_CRYPTO_LIBRARY="openssl/libcrypto.a" \
+	  -DOPENSSL_SSL_LIBRARY="openssl/libssl.a" \
+      -G "Unix Makefiles" $@ .. 
+
+emmake make

scripts/emscripten_openssl.sh

@@ -0,0 +1,25 @@
+#!/usr/bin/env bash
+# Build OpenSSL
+
+BUILD_DIR=$1
+OPENSSL_VERSION=1.1.1d
+
+if [ ! -d "$BUILD_DIR" ]; then
+	mkdir -p "$BUILD_DIR"
+
+	wget https://www.openssl.org/source/openssl-${OPENSSL_VERSION}.tar.gz
+	tar xf openssl-${OPENSSL_VERSION}.tar.gz -C "$BUILD_DIR" --strip 1
+	rm -f openssl-${OPENSSL_VERSION}.tar.gz
+fi
+
+pushd "$BUILD_DIR"
+
+emconfigure ./Configure gcc -no-tests -no-asm -static -no-sock \
+	-no-afalgeng -DOPENSSL_SYS_NETWARE -DSIG_DFL=0 -DSIG_IGN=0 \
+	-DHAVE_FORK=0 -DOPENSSL_NO_AFALGENG=1 --with-rand-seed=getrandom
+
+sed -i 's|^CROSS_COMPILE.*$|CROSS_COMPILE=|g' Makefile
+#sed -i -E 's|^CFLAGS=(.*)$|CFLAGS=\1 -D__STDC_NO_ATOMICS__=1|g' Makefile
+
+emmake make -j 12 build_generated libssl.a libcrypto.a
+popd