hook up wasi to wasmer

Cargo.toml

@@ -28,6 +28,7 @@ wasmer-runtime-core = { path = "lib/runtime-core" }
 wasmer-emscripten = { path = "lib/emscripten" }
 wasmer-llvm-backend = { path = "lib/llvm-backend", optional = true }
 wasmer-dynasm-backend = { path = "lib/dynasm-backend", optional = true }
+wasmer-wasi = { path = "lib/wasi", optional = true }
 
 [workspace]
 members = ["lib/clif-backend", "lib/dynasm-backend", "lib/runtime", "lib/runtime-core", "lib/emscripten", "lib/spectests", "lib/win-exception-handler", "lib/runtime-c-api", "lib/llvm-backend", "lib/wasi"]
@@ -42,4 +43,5 @@ default = ["fast-tests"]
 # This feature will allow cargo test to run much faster
 fast-tests = []
 llvm = ["wasmer-llvm-backend"]
-dynasm = ["wasmer-dynasm-backend"]
+dynasm = ["wasmer-dynasm-backend"]
+wasi = ["wasmer-wasi"]

lib/wasi/src/lib.rs

@@ -1,10 +1,14 @@
 mod state;
 mod syscalls;
+mod utils;
+
 use self::state::WasiState;
 use self::syscalls::*;
 
 use std::ffi::c_void;
 
+pub use self::utils::is_wasi_module;
+
 use wasmer_runtime_core::{func, import::ImportObject, imports};
 
 pub fn generate_import_object(args: Vec<Vec<u8>>, envs: Vec<Vec<u8>>) -> ImportObject {

lib/wasi/src/utils.rs

@@ -0,0 +1,15 @@
+use wasmer_runtime_core::module::Module;
+
+/// Check if a provided module is compiled with WASI support
+pub fn is_wasi_module(module: &Module) -> bool {
+    for (_, import_name) in &module.info().imported_functions {
+        let namespace = module
+            .info()
+            .namespace_table
+            .get(import_name.namespace_index);
+        if namespace == "wasi_unstable" {
+            return true;
+        }
+    }
+    false
+}

src/bin/wasmer.rs

@@ -15,6 +15,8 @@ use wasmer::*;
 use wasmer_emscripten;
 use wasmer_runtime::cache::{Cache as BaseCache, FileSystemCache, WasmHash, WASMER_VERSION_HASH};
 use wasmer_runtime_core::backend::CompilerConfig;
+#[cfg(feature = "wasi")]
+use wasmer_wasi;
 
 #[derive(Debug, StructOpt)]
 #[structopt(name = "wasmer", about = "Wasm execution runtime.")]
@@ -200,6 +202,8 @@ fn execute_wasm(options: &Run) -> Result<(), String> {
         .map_err(|e| format!("Can't compile module: {:?}", e))?
     };
 
+    // TODO: refactor this
+    #[cfg(not(features = "wasi"))]
     let (_abi, import_object, _em_globals) = if wasmer_emscripten::is_emscripten_module(&module) {
         let mut emscripten_globals = wasmer_emscripten::EmscriptenGlobals::new(&module);
         (
@@ -215,6 +219,25 @@ fn execute_wasm(options: &Run) -> Result<(), String> {
         )
     };
 
+    #[cfg(features = "wasi")]
+    let (_abi, import_object) = if wasmer_wasi::is_wasi_module(&module) {
+        (
+            InstanceABI::WASI,
+            wasmer_wasi::generate_import_object(
+                options.args.iter().map(|arg| arg.into_bytes()).collect(),
+                env::vars()
+                    .iter()
+                    .map(|(k, v)| format!("{}={}", k, v).into_bytes())
+                    .collect(),
+            ),
+        )
+    } else {
+        (
+            InstanceABI::None,
+            wasmer_runtime_core::import::ImportObject::new(),
+        )
+    };
+
     let mut instance = module
         .instantiate(&import_object)
         .map_err(|e| format!("Can't instantiate module: {:?}", e))?;

src/webassembly.rs

@@ -21,6 +21,7 @@ pub struct ResultObject {
 #[derive(PartialEq)]
 pub enum InstanceABI {
     Emscripten,
+    WASI,
     None,
 }