Add wasi state

lib/wasi/src/lib.rs

@@ -1,14 +1,33 @@
+mod state;
 mod syscalls;
-use syscalls::*;
+use self::state::WasiState;
+use self::syscalls::*;
+
+use std::ffi::c_void;
 
 use wasmer_runtime_core::{func, import::ImportObject, imports};
 
-pub fn generate_import_object() -> ImportObject {
+pub fn generate_import_object(args: Vec<u8>, envs: Vec<u8>) -> ImportObject {
+    let state_gen = move || {
+        fn state_dtor(data: *mut c_void) {
+            unsafe {
+                drop(Box::from_raw(data as *mut WasiState));
+            }
+        }
+
+        let state = Box::new(WasiState {
+            args: &args[..],
+            envs: &envs[..],
+        });
+
+        (
+            Box::leak(state) as *mut WasiState as *mut c_void,
+            state_dtor as fn(*mut c_void),
+        )
+    };
     imports! {
         // This generates the wasi state.
-        || {
-            // returns (pointer to state, function that can destruct the state).
-        },
+        state_gen,
         "wasi_unstable" => {
             "__wasi_args_get" => func!(__wasi_args_get),
             "__wasi_args_sizes_get" => func!(__wasi_args_sizes_get),

lib/wasi/src/state.rs

@@ -0,0 +1,5 @@
+pub struct WasiState<'a> {
+    // vfs: Vfs,
+    pub args: &'a [u8],
+    pub envs: &'a [u8],
+}

lib/wasi/src/syscalls/mod.rs

@@ -1,5 +1,10 @@
+use crate::state::WasiState;
 use wasmer_runtime_core::vm::Ctx;
 
+fn get_wasi_state(ctx: &mut Ctx) -> &mut WasiState {
+    unsafe { &mut *(ctx.data as *mut WasiState) }
+}
+
 pub fn __wasi_args_get(ctx: &mut Ctx) {
     unimplemented!()
 }