forked from AbleOS/ableos
88 lines
2.9 KiB
Rust
88 lines
2.9 KiB
Rust
use wasmi::{
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Error, Externals, FuncInstance, FuncRef, ModuleImportResolver, RuntimeArgs, RuntimeValue,
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Signature, Trap, ValueType,
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};
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pub struct HostExternals {}
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const ADD_FUNC_INDEX: usize = 0;
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const SEND_SIGNAL_INDEX: usize = 1;
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const GET_TIME_INDEX: usize = 2;
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impl Externals for HostExternals {
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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 {
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ADD_FUNC_INDEX => {
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let a: u32 = args.nth_checked(0)?;
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let b: u32 = args.nth_checked(1)?;
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let result = a + b;
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println!("SYSCALL: {} + {} = {}", a, b, result);
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Ok(Some(RuntimeValue::I32(result as i32)))
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}
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SEND_SIGNAL_INDEX => {
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let pid: u32 = args.nth_checked(0)?;
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let signal: u32 = args.nth_checked(1)?;
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println!("SYSCALL: send signal {} to pid {}", signal, pid);
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let ret = RuntimeValue::I32(0);
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Ok(Some(ret))
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}
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GET_TIME_INDEX => {
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use core::sync::atomic::Ordering::*;
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x86_64::instructions::interrupts::disable();
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let tick_time = kernel::TICK.load(Relaxed);
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x86_64::instructions::interrupts::enable();
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let ret = RuntimeValue::I64(tick_time.try_into().unwrap());
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Ok(Some(ret))
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}
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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 HostExternals {
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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 {
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ADD_FUNC_INDEX => (&[ValueType::I32, ValueType::I32], Some(ValueType::I32)),
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SEND_SIGNAL_INDEX => (&[ValueType::I32, ValueType::I32], Some(ValueType::I32)),
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GET_TIME_INDEX => (&[], Some(ValueType::I32)),
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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 ModuleImportResolver for HostExternals {
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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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"add" => ADD_FUNC_INDEX,
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"send_signal" => SEND_SIGNAL_INDEX,
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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(&[ValueType::I32, ValueType::I32][..], Some(ValueType::I32)),
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index,
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))
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}
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}
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