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};
55
56#[repr(C)]
57pub struct wasm_trap_t {
58    pub(crate) error: Error,
59}
60
61// This is currently only needed for the `wasm_trap_copy` API in the C API.
62//
63// For now the impl here is "fake it til you make it" since this is losing
64// context by only cloning the error string.
65impl Clone for wasm_trap_t {
66    fn clone(&self) -> wasm_trap_t {
67        wasm_trap_t {
68            error: format_err!("{:?}", self.error),
69        }
70    }
71}
72
73wasmtime_c_api_macros::declare_ref!(wasm_trap_t);
74
75impl wasm_trap_t {
76    pub(crate) fn new(error: Error) -> wasm_trap_t {
77        wasm_trap_t { error }
78    }
79}
80
81#[repr(C)]
82#[derive(Clone)]
83pub struct wasm_frame_t<'a> {
84    trace: &'a WasmBacktrace,
85    idx: usize,
86    func_name: OnceCell<Option<wasm_name_t>>,
87    module_name: OnceCell<Option<wasm_name_t>>,
88}
89
90wasmtime_c_api_macros::declare_own!(wasm_frame_t);
91
92pub type wasm_message_t = wasm_name_t;
93
94#[unsafe(no_mangle)]
95pub extern "C" fn wasm_trap_new(
96    _store: &wasm_store_t,
97    message: &wasm_message_t,
98) -> Box<wasm_trap_t> {
99    let message = message.as_slice();
100    if message[message.len() - 1] != 0 {
101        panic!("wasm_trap_new message stringz expected");
102    }
103    let message = String::from_utf8_lossy(&message[..message.len() - 1]);
104    Box::new(wasm_trap_t {
105        error: Error::msg(message.into_owned()),
106    })
107}
108
109#[unsafe(no_mangle)]
110pub unsafe extern "C" fn wasmtime_trap_new(message: *const u8, len: usize) -> Box<wasm_trap_t> {
111    let bytes = crate::slice_from_raw_parts(message, len);
112    let message = String::from_utf8_lossy(&bytes);
113    Box::new(wasm_trap_t {
114        error: Error::msg(message.into_owned()),
115    })
116}
117
118#[unsafe(no_mangle)]
119pub unsafe extern "C" fn wasmtime_trap_new_code(code: u8) -> Box<wasm_trap_t> {
120    let trap = Trap::from_u8(code).unwrap();
121    Box::new(wasm_trap_t {
122        error: Error::new(trap),
123    })
124}
125
126#[unsafe(no_mangle)]
127pub extern "C" fn wasm_trap_message(trap: &wasm_trap_t, out: &mut wasm_message_t) {
128    let mut buffer = Vec::new();
129    buffer.extend_from_slice(format!("{:?}", trap.error).as_bytes());
130    buffer.reserve_exact(1);
131    buffer.push(0);
132    out.set_buffer(buffer);
133}
134
135#[unsafe(no_mangle)]
136pub extern "C" fn wasm_trap_origin(raw: &wasm_trap_t) -> Option<Box<wasm_frame_t<'_>>> {
137    let trace = match raw.error.downcast_ref::<WasmBacktrace>() {
138        Some(trap) => trap,
139        None => return None,
140    };
141    if trace.frames().len() > 0 {
142        Some(Box::new(wasm_frame_t {
143            trace,
144            idx: 0,
145            func_name: OnceCell::new(),
146            module_name: OnceCell::new(),
147        }))
148    } else {
149        None
150    }
151}
152
153#[unsafe(no_mangle)]
154pub extern "C" fn wasm_trap_trace<'a>(raw: &'a wasm_trap_t, out: &mut wasm_frame_vec_t<'a>) {
155    error_trace(&raw.error, out)
156}
157
158pub(crate) fn error_trace<'a>(error: &'a Error, out: &mut wasm_frame_vec_t<'a>) {
159    let trace = match error.downcast_ref::<WasmBacktrace>() {
160        Some(trap) => trap,
161        None => return out.set_buffer(Vec::new()),
162    };
163    let vec = (0..trace.frames().len())
164        .map(|idx| {
165            Some(Box::new(wasm_frame_t {
166                trace,
167                idx,
168                func_name: OnceCell::new(),
169                module_name: OnceCell::new(),
170            }))
171        })
172        .collect();
173    out.set_buffer(vec);
174}
175
176#[unsafe(no_mangle)]
177pub extern "C" fn wasmtime_trap_code(raw: &wasm_trap_t, code: &mut u8) -> bool {
178    let trap = match raw.error.downcast_ref::<Trap>() {
179        Some(trap) => trap,
180        None => return false,
181    };
182    *code = *trap as u8;
183    true
184}
185
186#[unsafe(no_mangle)]
187pub extern "C" fn wasm_frame_func_index(frame: &wasm_frame_t<'_>) -> u32 {
188    frame.trace.frames()[frame.idx].func_index()
189}
190
191#[unsafe(no_mangle)]
192pub extern "C" fn wasmtime_frame_func_name<'a>(
193    frame: &'a wasm_frame_t<'_>,
194) -> Option<&'a wasm_name_t> {
195    frame
196        .func_name
197        .get_or_init(|| {
198            frame.trace.frames()[frame.idx]
199                .func_name()
200                .map(|s| wasm_name_t::from(s.to_string().into_bytes()))
201        })
202        .as_ref()
203}
204
205#[unsafe(no_mangle)]
206pub extern "C" fn wasmtime_frame_module_name<'a>(
207    frame: &'a wasm_frame_t<'_>,
208) -> Option<&'a wasm_name_t> {
209    frame
210        .module_name
211        .get_or_init(|| {
212            frame.trace.frames()[frame.idx]
213                .module()
214                .name()
215                .map(|s| wasm_name_t::from(s.to_string().into_bytes()))
216        })
217        .as_ref()
218}
219
220#[unsafe(no_mangle)]
221pub extern "C" fn wasm_frame_func_offset(frame: &wasm_frame_t<'_>) -> usize {
222    frame.trace.frames()[frame.idx]
223        .func_offset()
224        .unwrap_or(usize::MAX)
225}
226
227#[unsafe(no_mangle)]
228pub extern "C" fn wasm_frame_instance(_arg1: *const wasm_frame_t<'_>) -> *mut wasm_instance_t {
229    unimplemented!("wasm_frame_instance")
230}
231
232#[unsafe(no_mangle)]
233pub extern "C" fn wasm_frame_module_offset(frame: &wasm_frame_t<'_>) -> usize {
234    frame.trace.frames()[frame.idx]
235        .module_offset()
236        .unwrap_or(usize::MAX)
237}
238
239#[unsafe(no_mangle)]
240pub extern "C" fn wasm_frame_copy<'a>(frame: &wasm_frame_t<'a>) -> Box<wasm_frame_t<'a>> {
241    Box::new(frame.clone())
242}
wasmtime_c_api/trap.rs

wasmtime_c_api/
trap.rs
