wasmtime_c_api/
trap.rs

1use crate::{wasm_frame_vec_t, wasm_instance_t, wasm_name_t, wasm_store_t};
2use std::cell::OnceCell;
3use wasmtime::{Error, Trap, WasmBacktrace, format_err};
4
5// Help ensure the Rust enum matches the C one.  If any of these assertions
6// fail, please update both this code and `trap.h` to sync them with
7// `trap_encoding.rs`.
8const _: () = {
9    assert!(Trap::StackOverflow as u8 == 0);
10    assert!(Trap::MemoryOutOfBounds as u8 == 1);
11    assert!(Trap::HeapMisaligned as u8 == 2);
12    assert!(Trap::TableOutOfBounds as u8 == 3);
13    assert!(Trap::IndirectCallToNull as u8 == 4);
14    assert!(Trap::BadSignature as u8 == 5);
15    assert!(Trap::IntegerOverflow as u8 == 6);
16    assert!(Trap::IntegerDivisionByZero as u8 == 7);
17    assert!(Trap::BadConversionToInteger as u8 == 8);
18    assert!(Trap::UnreachableCodeReached as u8 == 9);
19    assert!(Trap::Interrupt as u8 == 10);
20    assert!(Trap::OutOfFuel as u8 == 11);
21    assert!(Trap::AtomicWaitNonSharedMemory as u8 == 12);
22    assert!(Trap::NullReference as u8 == 13);
23    assert!(Trap::ArrayOutOfBounds as u8 == 14);
24    assert!(Trap::AllocationTooLarge as u8 == 15);
25    assert!(Trap::CastFailure as u8 == 16);
26    assert!(Trap::CannotEnterComponent as u8 == 17);
27    assert!(Trap::NoAsyncResult as u8 == 18);
28    assert!(Trap::UnhandledTag as u8 == 19);
29    assert!(Trap::ContinuationAlreadyConsumed as u8 == 20);
30    assert!(Trap::DisabledOpcode as u8 == 21);
31    assert!(Trap::AsyncDeadlock as u8 == 22);
32    assert!(Trap::CannotLeaveComponent as u8 == 23);
33    assert!(Trap::CannotBlockSyncTask as u8 == 24);
34    assert!(Trap::InvalidChar as u8 == 25);
35    assert!(Trap::DebugAssertStringEncodingFinished as u8 == 26);
36    assert!(Trap::DebugAssertEqualCodeUnits as u8 == 27);
37    assert!(Trap::DebugAssertPointerAligned as u8 == 28);
38    assert!(Trap::DebugAssertUpperBitsUnset as u8 == 29);
39    assert!(Trap::StringOutOfBounds as u8 == 30);
40    assert!(Trap::ListOutOfBounds as u8 == 31);
41    assert!(Trap::InvalidDiscriminant as u8 == 32);
42    assert!(Trap::UnalignedPointer as u8 == 33);
43    assert!(Trap::TaskCancelNotCancelled as u8 == 34);
44    assert!(Trap::TaskCancelOrReturnTwice as u8 == 35);
45    assert!(Trap::SubtaskCancelAfterTerminal as u8 == 36);
46    assert!(Trap::TaskReturnInvalid as u8 == 37);
47    assert!(Trap::WaitableSetDropHasWaiters as u8 == 38);
48    assert!(Trap::SubtaskDropNotResolved as u8 == 39);
49    assert!(Trap::ThreadNewIndirectInvalidType as u8 == 40);
50    assert!(Trap::ThreadNewIndirectUninitialized as u8 == 41);
51    assert!(Trap::BackpressureOverflow as u8 == 42);
52    assert!(Trap::UnsupportedCallbackCode as u8 == 43);
53    assert!(Trap::CannotResumeThread as u8 == 44);
54    assert!(Trap::ConcurrentFutureStreamOp as u8 == 45);
55};
56
57#[repr(C)]
58pub struct wasm_trap_t {
59    pub(crate) error: Error,
60}
61
62// This is currently only needed for the `wasm_trap_copy` API in the C API.
63//
64// For now the impl here is "fake it til you make it" since this is losing
65// context by only cloning the error string.
66impl Clone for wasm_trap_t {
67    fn clone(&self) -> wasm_trap_t {
68        wasm_trap_t {
69            error: format_err!("{:?}", self.error),
70        }
71    }
72}
73
74wasmtime_c_api_macros::declare_ref!(wasm_trap_t);
75
76impl wasm_trap_t {
77    pub(crate) fn new(error: Error) -> wasm_trap_t {
78        wasm_trap_t { error }
79    }
80}
81
82#[repr(C)]
83#[derive(Clone)]
84pub struct wasm_frame_t<'a> {
85    trace: &'a WasmBacktrace,
86    idx: usize,
87    func_name: OnceCell<Option<wasm_name_t>>,
88    module_name: OnceCell<Option<wasm_name_t>>,
89}
90
91wasmtime_c_api_macros::declare_own!(wasm_frame_t);
92
93pub type wasm_message_t = wasm_name_t;
94
95#[unsafe(no_mangle)]
96pub extern "C" fn wasm_trap_new(
97    _store: &wasm_store_t,
98    message: &wasm_message_t,
99) -> Box<wasm_trap_t> {
100    let message = message.as_slice();
101    if message[message.len() - 1] != 0 {
102        panic!("wasm_trap_new message stringz expected");
103    }
104    let message = String::from_utf8_lossy(&message[..message.len() - 1]);
105    Box::new(wasm_trap_t {
106        error: Error::msg(message.into_owned()),
107    })
108}
109
110#[unsafe(no_mangle)]
111pub unsafe extern "C" fn wasmtime_trap_new(message: *const u8, len: usize) -> Box<wasm_trap_t> {
112    let bytes = crate::slice_from_raw_parts(message, len);
113    let message = String::from_utf8_lossy(&bytes);
114    Box::new(wasm_trap_t {
115        error: Error::msg(message.into_owned()),
116    })
117}
118
119#[unsafe(no_mangle)]
120pub unsafe extern "C" fn wasmtime_trap_new_code(code: u8) -> Box<wasm_trap_t> {
121    let trap = Trap::from_u8(code).unwrap();
122    Box::new(wasm_trap_t {
123        error: Error::new(trap),
124    })
125}
126
127#[unsafe(no_mangle)]
128pub extern "C" fn wasm_trap_message(trap: &wasm_trap_t, out: &mut wasm_message_t) {
129    let mut buffer = Vec::new();
130    buffer.extend_from_slice(format!("{:?}", trap.error).as_bytes());
131    buffer.reserve_exact(1);
132    buffer.push(0);
133    out.set_buffer(buffer);
134}
135
136#[unsafe(no_mangle)]
137pub extern "C" fn wasm_trap_origin(raw: &wasm_trap_t) -> Option<Box<wasm_frame_t<'_>>> {
138    let trace = match raw.error.downcast_ref::<WasmBacktrace>() {
139        Some(trap) => trap,
140        None => return None,
141    };
142    if trace.frames().len() > 0 {
143        Some(Box::new(wasm_frame_t {
144            trace,
145            idx: 0,
146            func_name: OnceCell::new(),
147            module_name: OnceCell::new(),
148        }))
149    } else {
150        None
151    }
152}
153
154#[unsafe(no_mangle)]
155pub extern "C" fn wasm_trap_trace<'a>(raw: &'a wasm_trap_t, out: &mut wasm_frame_vec_t<'a>) {
156    error_trace(&raw.error, out)
157}
158
159pub(crate) fn error_trace<'a>(error: &'a Error, out: &mut wasm_frame_vec_t<'a>) {
160    let trace = match error.downcast_ref::<WasmBacktrace>() {
161        Some(trap) => trap,
162        None => return out.set_buffer(Vec::new()),
163    };
164    let vec = (0..trace.frames().len())
165        .map(|idx| {
166            Some(Box::new(wasm_frame_t {
167                trace,
168                idx,
169                func_name: OnceCell::new(),
170                module_name: OnceCell::new(),
171            }))
172        })
173        .collect();
174    out.set_buffer(vec);
175}
176
177#[unsafe(no_mangle)]
178pub extern "C" fn wasmtime_trap_code(raw: &wasm_trap_t, code: &mut u8) -> bool {
179    let trap = match raw.error.downcast_ref::<Trap>() {
180        Some(trap) => trap,
181        None => return false,
182    };
183    *code = *trap as u8;
184    true
185}
186
187#[unsafe(no_mangle)]
188pub extern "C" fn wasm_frame_func_index(frame: &wasm_frame_t<'_>) -> u32 {
189    frame.trace.frames()[frame.idx].func_index()
190}
191
192#[unsafe(no_mangle)]
193pub extern "C" fn wasmtime_frame_func_name<'a>(
194    frame: &'a wasm_frame_t<'_>,
195) -> Option<&'a wasm_name_t> {
196    frame
197        .func_name
198        .get_or_init(|| {
199            frame.trace.frames()[frame.idx]
200                .func_name()
201                .map(|s| wasm_name_t::from(s.to_string().into_bytes()))
202        })
203        .as_ref()
204}
205
206#[unsafe(no_mangle)]
207pub extern "C" fn wasmtime_frame_module_name<'a>(
208    frame: &'a wasm_frame_t<'_>,
209) -> Option<&'a wasm_name_t> {
210    frame
211        .module_name
212        .get_or_init(|| {
213            frame.trace.frames()[frame.idx]
214                .module()
215                .name()
216                .map(|s| wasm_name_t::from(s.to_string().into_bytes()))
217        })
218        .as_ref()
219}
220
221#[unsafe(no_mangle)]
222pub extern "C" fn wasm_frame_func_offset(frame: &wasm_frame_t<'_>) -> usize {
223    frame.trace.frames()[frame.idx]
224        .func_offset()
225        .unwrap_or(usize::MAX)
226}
227
228#[unsafe(no_mangle)]
229pub extern "C" fn wasm_frame_instance(_arg1: *const wasm_frame_t<'_>) -> *mut wasm_instance_t {
230    unimplemented!("wasm_frame_instance")
231}
232
233#[unsafe(no_mangle)]
234pub extern "C" fn wasm_frame_module_offset(frame: &wasm_frame_t<'_>) -> usize {
235    frame.trace.frames()[frame.idx]
236        .module_offset()
237        .unwrap_or(usize::MAX)
238}
239
240#[unsafe(no_mangle)]
241pub extern "C" fn wasm_frame_copy<'a>(frame: &wasm_frame_t<'a>) -> Box<wasm_frame_t<'a>> {
242    Box::new(frame.clone())
243}
wasmtime_c_api/trap.rs

wasmtime_c_api/
trap.rs
