forked from AbleOS/ableos
103 lines
3.2 KiB
Rust
103 lines
3.2 KiB
Rust
// use wabt;
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use wasmi::{
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Error, Externals, FuncInstance, FuncRef, ImportsBuilder, ModuleImportResolver, ModuleInstance,
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RuntimeArgs, RuntimeValue, Signature, Trap, ValueType,
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};
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mod wasm_sys;
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use alloc::format;
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use wasm_sys::SysCall;
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struct HostFunctions;
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impl HostFunctions {
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fn check_signature(&self, index: usize, signature: &Signature) -> bool {
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let (params, ret_ty): (&[ValueType], Option<ValueType>) = match index.into() {
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SysCall::KILL => (&[], None),
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SysCall::EMPTY => (&[], None),
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_ => return false,
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};
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signature.params() == params && signature.return_type() == ret_ty
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}
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}
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impl Externals for HostFunctions {
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fn invoke_index(
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&mut self,
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index: usize,
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_args: RuntimeArgs,
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) -> Result<Option<RuntimeValue>, Trap> {
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match index.into() {
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// Take in one arg discard the rest
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SysCall::KILL => {
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println!("Program killed");
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Ok(None)
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}
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// Do nothing
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SysCall::EMPTY => Ok(None),
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SysCall::EXIT => Ok(None),
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SysCall::CONSOLE_RESET => Ok(None),
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SysCall::CONSOLE_IN => Ok(None),
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SysCall::CONSOLE_OUT => Ok(None),
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SysCall::CONSOLE_GET_TITLE => Ok(None),
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SysCall::CONSOLE_SET_TITLE => Ok(None),
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_ => panic!("Unimplemented function at {}", index),
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}
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}
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}
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impl ModuleImportResolver for HostFunctions {
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fn resolve_func(&self, field_name: &str, signature: &Signature) -> Result<FuncRef, Error> {
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let index = match field_name {
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"kill" => SysCall::KILL as usize,
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"empty" => SysCall::EMPTY as usize,
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"exit" => SysCall::EXIT as usize,
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_ => {
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return Err(Error::Instantiation(format!(
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"Export {} not found",
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field_name
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)))
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}
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};
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if !self.check_signature(index, signature) {
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return Err(Error::Instantiation(format!(
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"Export {} has a bad signature",
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field_name
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)));
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}
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Ok(FuncInstance::alloc_host(
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Signature::new(&[][..], None),
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index,
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))
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}
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}
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pub fn evaluate() {
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let wasm_binary = // Spacer
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include_bytes!("rust.wasm");
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// Load wasm binary and prepare it for instantiation.
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let module = wasmi::Module::from_buffer(&wasm_binary).expect("failed to load wasm");
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let imports = ImportsBuilder::new().with_resolver("env", &HostFunctions);
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// Instantiate a module with empty imports and
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// assert that there is no `start` function.
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let instance = ModuleInstance::new(&module, &imports)
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.expect("failed to instantiate wasm module")
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.assert_no_start();
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// Finally, invoke the exported function "test" with no parameters
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// and empty external function executor.
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let result: i32 = instance
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.invoke_export("_start", &[], &mut HostFunctions)
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// .with_resolver(&mut HostFunctions)
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.expect("failed to execute export")
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.unwrap()
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.try_into()
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.unwrap();
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println!(
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"{:?}",
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result // .unwrap()
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);
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}
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