filestore: add example WASM unknown module written in Rust

Signed-off-by: deadprogram <[email protected]>

filestore/modules/pingrs/.cargo/config.toml

@@ -0,0 +1,5 @@
+[target."wasm32-unknown-unknown"]
+rustflags = ["-C", "target-feature=+atomics,+bulk-memory",
+             "-C", "link-arg=--initial-memory=65536",
+             "-C", "link-arg=--max-memory=65536",
+             "-C", "link-arg=-zstack-size=4096"]

filestore/modules/pingrs/.gitignore

@@ -0,0 +1 @@
+/target

filestore/modules/pingrs/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "pingrs"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+
+[lib]
+crate-type = ["cdylib"]

filestore/modules/pingrs/README.md

@@ -0,0 +1,22 @@
+# pingrs
+
+WASM unknown module written in Rust
+
+## How to install
+
+- Install Rust.
+
+- Install the `wasm32-unknown-unknown` target.
+
+```bash
+rustup target add wasm32-unknown-unknown
+```
+
+## How to build module
+
+```bash
+cd modules/pingrs
+cargo build --target wasm32-unknown-unknown --release
+cd ../..
+cp ./modules/pingrs/target/wasm32-unknown-unknown/release/pingrs.wasm ./modules/
+```

filestore/modules/pingrs/src/lib.rs

@@ -0,0 +1,16 @@
+#![no_std]
+
+#[panic_handler]
+fn handle_panic(_: &core::panic::PanicInfo) -> ! {
+    loop {}
+}
+
+#[no_mangle]
+pub extern fn ping() {
+    unsafe {pong()};
+}
+
+#[link(wasm_import_module = "hosted")]
+extern {
+    fn pong();
+}