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    assert!(Trap::ReferenceCountOverflow as u8 == 46);
56    assert!(Trap::StreamOpTooBig as u8 == 47);
57};
58
59#[repr(C)]
60pub struct wasm_trap_t {
61    pub(crate) error: Error,
62}
63
64// This is currently only needed for the `wasm_trap_copy` API in the C API.
65//
66// For now the impl here is "fake it til you make it" since this is losing
67// context by only cloning the error string.
68impl Clone for wasm_trap_t {
69    fn clone(&self) -> wasm_trap_t {
70        wasm_trap_t {
71            error: format_err!("{:?}", self.error),
72        }
73    }
74}
75
76wasmtime_c_api_macros::declare_ref!(wasm_trap_t);
77
78impl wasm_trap_t {
79    pub(crate) fn new(error: Error) -> wasm_trap_t {
80        wasm_trap_t { error }
81    }
82}
83
84#[repr(C)]
85#[derive(Clone)]
86pub struct wasm_frame_t<'a> {
87    trace: &'a WasmBacktrace,
88    idx: usize,
89    func_name: OnceCell<Option<wasm_name_t>>,
90    module_name: OnceCell<Option<wasm_name_t>>,
91}
92
93wasmtime_c_api_macros::declare_own!(wasm_frame_t);
94
95pub type wasm_message_t = wasm_name_t;
96
97#[unsafe(no_mangle)]
98pub extern "C" fn wasm_trap_new(
99    _store: &wasm_store_t,
100    message: &wasm_message_t,
101) -> Box<wasm_trap_t> {
102    let message = message.as_slice();
103    if message[message.len() - 1] != 0 {
104        panic!("wasm_trap_new message stringz expected");
105    }
106    let message = String::from_utf8_lossy(&message[..message.len() - 1]);
107    Box::new(wasm_trap_t {
108        error: Error::msg(message.into_owned()),
109    })
110}
111
112#[unsafe(no_mangle)]
113pub unsafe extern "C" fn wasmtime_trap_new(message: *const u8, len: usize) -> Box<wasm_trap_t> {
114    let bytes = crate::slice_from_raw_parts(message, len);
115    let message = String::from_utf8_lossy(&bytes);
116    Box::new(wasm_trap_t {
117        error: Error::msg(message.into_owned()),
118    })
119}
120
121#[unsafe(no_mangle)]
122pub unsafe extern "C" fn wasmtime_trap_new_code(code: u8) -> Box<wasm_trap_t> {
123    let trap = Trap::from_u8(code).unwrap();
124    Box::new(wasm_trap_t {
125        error: Error::new(trap),
126    })
127}
128
129#[unsafe(no_mangle)]
130pub extern "C" fn wasm_trap_message(trap: &wasm_trap_t, out: &mut wasm_message_t) {
131    let mut buffer = Vec::new();
132    buffer.extend_from_slice(format!("{:?}", trap.error).as_bytes());
133    buffer.reserve_exact(1);
134    buffer.push(0);
135    out.set_buffer(buffer);
136}
137
138#[unsafe(no_mangle)]
139pub extern "C" fn wasm_trap_origin(raw: &wasm_trap_t) -> Option<Box<wasm_frame_t<'_>>> {
140    let trace = match raw.error.downcast_ref::<WasmBacktrace>() {
141        Some(trap) => trap,
142        None => return None,
143    };
144    if trace.frames().len() > 0 {
145        Some(Box::new(wasm_frame_t {
146            trace,
147            idx: 0,
148            func_name: OnceCell::new(),
149            module_name: OnceCell::new(),
150        }))
151    } else {
152        None
153    }
154}
155
156#[unsafe(no_mangle)]
157pub extern "C" fn wasm_trap_trace<'a>(raw: &'a wasm_trap_t, out: &mut wasm_frame_vec_t<'a>) {
158    error_trace(&raw.error, out)
159}
160
161pub(crate) fn error_trace<'a>(error: &'a Error, out: &mut wasm_frame_vec_t<'a>) {
162    let trace = match error.downcast_ref::<WasmBacktrace>() {
163        Some(trap) => trap,
164        None => return out.set_buffer(Vec::new()),
165    };
166    let vec = (0..trace.frames().len())
167        .map(|idx| {
168            Some(Box::new(wasm_frame_t {
169                trace,
170                idx,
171                func_name: OnceCell::new(),
172                module_name: OnceCell::new(),
173            }))
174        })
175        .collect();
176    out.set_buffer(vec);
177}
178
179#[unsafe(no_mangle)]
180pub extern "C" fn wasmtime_trap_code(raw: &wasm_trap_t, code: &mut u8) -> bool {
181    let trap = match raw.error.downcast_ref::<Trap>() {
182        Some(trap) => trap,
183        None => return false,
184    };
185    *code = *trap as u8;
186    true
187}
188
189#[unsafe(no_mangle)]
190pub extern "C" fn wasm_frame_func_index(frame: &wasm_frame_t<'_>) -> u32 {
191    frame.trace.frames()[frame.idx].func_index()
192}
193
194#[unsafe(no_mangle)]
195pub extern "C" fn wasmtime_frame_func_name<'a>(
196    frame: &'a wasm_frame_t<'_>,
197) -> Option<&'a wasm_name_t> {
198    frame
199        .func_name
200        .get_or_init(|| {
201            frame.trace.frames()[frame.idx]
202                .func_name()
203                .map(|s| wasm_name_t::from(s.to_string().into_bytes()))
204        })
205        .as_ref()
206}
207
208#[unsafe(no_mangle)]
209pub extern "C" fn wasmtime_frame_module_name<'a>(
210    frame: &'a wasm_frame_t<'_>,
211) -> Option<&'a wasm_name_t> {
212    frame
213        .module_name
214        .get_or_init(|| {
215            frame.trace.frames()[frame.idx]
216                .module()
217                .name()
218                .map(|s| wasm_name_t::from(s.to_string().into_bytes()))
219        })
220        .as_ref()
221}
222
223#[unsafe(no_mangle)]
224pub extern "C" fn wasm_frame_func_offset(frame: &wasm_frame_t<'_>) -> usize {
225    frame.trace.frames()[frame.idx]
226        .func_offset()
227        .unwrap_or(usize::MAX)
228}
229
230#[unsafe(no_mangle)]
231pub extern "C" fn wasm_frame_instance(_arg1: *const wasm_frame_t<'_>) -> *mut wasm_instance_t {
232    unimplemented!("wasm_frame_instance")
233}
234
235#[unsafe(no_mangle)]
236pub extern "C" fn wasm_frame_module_offset(frame: &wasm_frame_t<'_>) -> usize {
237    frame.trace.frames()[frame.idx]
238        .module_offset()
239        .unwrap_or(usize::MAX)
240}
241
242#[unsafe(no_mangle)]
243pub extern "C" fn wasm_frame_copy<'a>(frame: &wasm_frame_t<'a>) -> Box<wasm_frame_t<'a>> {
244    Box::new(frame.clone())
245}
wasmtime_c_api/trap.rs

wasmtime_c_api/
trap.rs
