mirror of
https://github.com/fluencelabs/wasmer
synced 2024-12-14 22:55:40 +00:00
54 lines
1.7 KiB
Rust
54 lines
1.7 KiB
Rust
//! Installing signal handlers allows us to handle traps and out-of-bounds memory
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//! accesses that occur when runniing WebAssembly.
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//!
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//! This code is inspired by: https://github.com/pepyakin/wasmtime/commit/625a2b6c0815b21996e111da51b9664feb174622
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//!
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//! When a WebAssembly module triggers any traps, we perform recovery here.
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//!
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//! This module uses TLS (thread-local storage) to track recovery information. Since the four signals we're handling
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//! are very special, the async signal unsafety of Rust's TLS implementation generally does not affect the correctness here
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//! unless you have memory unsafety elsewhere in your code.
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//!
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use std::any::Any;
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use std::cell::Cell;
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use wasmer_runtime_core::codegen::BreakpointMap;
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use wasmer_runtime_core::fault::{begin_unsafe_unwind, catch_unsafe_unwind, ensure_sighandler};
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use wasmer_runtime_core::typed_func::WasmTrapInfo;
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thread_local! {
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pub static TRAP_EARLY_DATA: Cell<Option<Box<dyn Any>>> = Cell::new(None);
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}
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pub unsafe fn trigger_trap() -> ! {
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begin_unsafe_unwind(Box::new(()));
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}
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pub enum CallProtError {
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Trap(WasmTrapInfo),
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Error(Box<dyn Any>),
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}
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pub fn call_protected<T>(
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f: impl FnOnce() -> T,
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breakpoints: Option<BreakpointMap>,
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) -> Result<T, CallProtError> {
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ensure_sighandler();
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unsafe {
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let ret = catch_unsafe_unwind(|| f(), breakpoints);
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match ret {
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Ok(x) => Ok(x),
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Err(e) => {
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if let Some(data) = TRAP_EARLY_DATA.with(|cell| cell.replace(None)) {
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Err(CallProtError::Error(data))
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} else {
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Err(CallProtError::Error(e))
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}
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}
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}
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}
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}
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pub unsafe fn throw(payload: Box<dyn Any>) -> ! {
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begin_unsafe_unwind(payload);
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}
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