xref: /wasmtime-44.0.1/crates/c-api/src/trap.rs (revision bda02c19)
1 use crate::{wasm_frame_vec_t, wasm_instance_t, wasm_name_t, wasm_store_t};
2 use std::cell::OnceCell;
3 use 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`.
8 const _: () = {
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 };
44 
45 #[repr(C)]
46 pub struct wasm_trap_t {
47     pub(crate) error: Error,
48 }
49 
50 // This is currently only needed for the `wasm_trap_copy` API in the C API.
51 //
52 // For now the impl here is "fake it til you make it" since this is losing
53 // context by only cloning the error string.
54 impl Clone for wasm_trap_t {
55     fn clone(&self) -> wasm_trap_t {
56         wasm_trap_t {
57             error: format_err!("{:?}", self.error),
58         }
59     }
60 }
61 
62 wasmtime_c_api_macros::declare_ref!(wasm_trap_t);
63 
64 impl wasm_trap_t {
65     pub(crate) fn new(error: Error) -> wasm_trap_t {
66         wasm_trap_t { error }
67     }
68 }
69 
70 #[repr(C)]
71 #[derive(Clone)]
72 pub struct wasm_frame_t<'a> {
73     trace: &'a WasmBacktrace,
74     idx: usize,
75     func_name: OnceCell<Option<wasm_name_t>>,
76     module_name: OnceCell<Option<wasm_name_t>>,
77 }
78 
79 wasmtime_c_api_macros::declare_own!(wasm_frame_t);
80 
81 pub type wasm_message_t = wasm_name_t;
82 
83 #[unsafe(no_mangle)]
84 pub extern "C" fn wasm_trap_new(
85     _store: &wasm_store_t,
86     message: &wasm_message_t,
87 ) -> Box<wasm_trap_t> {
88     let message = message.as_slice();
89     if message[message.len() - 1] != 0 {
90         panic!("wasm_trap_new message stringz expected");
91     }
92     let message = String::from_utf8_lossy(&message[..message.len() - 1]);
93     Box::new(wasm_trap_t {
94         error: Error::msg(message.into_owned()),
95     })
96 }
97 
98 #[unsafe(no_mangle)]
99 pub unsafe extern "C" fn wasmtime_trap_new(message: *const u8, len: usize) -> Box<wasm_trap_t> {
100     let bytes = crate::slice_from_raw_parts(message, len);
101     let message = String::from_utf8_lossy(&bytes);
102     Box::new(wasm_trap_t {
103         error: Error::msg(message.into_owned()),
104     })
105 }
106 
107 #[unsafe(no_mangle)]
108 pub unsafe extern "C" fn wasmtime_trap_new_code(code: u8) -> Box<wasm_trap_t> {
109     let trap = Trap::from_u8(code).unwrap();
110     Box::new(wasm_trap_t {
111         error: Error::new(trap),
112     })
113 }
114 
115 #[unsafe(no_mangle)]
116 pub extern "C" fn wasm_trap_message(trap: &wasm_trap_t, out: &mut wasm_message_t) {
117     let mut buffer = Vec::new();
118     buffer.extend_from_slice(format!("{:?}", trap.error).as_bytes());
119     buffer.reserve_exact(1);
120     buffer.push(0);
121     out.set_buffer(buffer);
122 }
123 
124 #[unsafe(no_mangle)]
125 pub extern "C" fn wasm_trap_origin(raw: &wasm_trap_t) -> Option<Box<wasm_frame_t<'_>>> {
126     let trace = match raw.error.downcast_ref::<WasmBacktrace>() {
127         Some(trap) => trap,
128         None => return None,
129     };
130     if trace.frames().len() > 0 {
131         Some(Box::new(wasm_frame_t {
132             trace,
133             idx: 0,
134             func_name: OnceCell::new(),
135             module_name: OnceCell::new(),
136         }))
137     } else {
138         None
139     }
140 }
141 
142 #[unsafe(no_mangle)]
143 pub extern "C" fn wasm_trap_trace<'a>(raw: &'a wasm_trap_t, out: &mut wasm_frame_vec_t<'a>) {
144     error_trace(&raw.error, out)
145 }
146 
147 pub(crate) fn error_trace<'a>(error: &'a Error, out: &mut wasm_frame_vec_t<'a>) {
148     let trace = match error.downcast_ref::<WasmBacktrace>() {
149         Some(trap) => trap,
150         None => return out.set_buffer(Vec::new()),
151     };
152     let vec = (0..trace.frames().len())
153         .map(|idx| {
154             Some(Box::new(wasm_frame_t {
155                 trace,
156                 idx,
157                 func_name: OnceCell::new(),
158                 module_name: OnceCell::new(),
159             }))
160         })
161         .collect();
162     out.set_buffer(vec);
163 }
164 
165 #[unsafe(no_mangle)]
166 pub extern "C" fn wasmtime_trap_code(raw: &wasm_trap_t, code: &mut u8) -> bool {
167     let trap = match raw.error.downcast_ref::<Trap>() {
168         Some(trap) => trap,
169         None => return false,
170     };
171     *code = *trap as u8;
172     true
173 }
174 
175 #[unsafe(no_mangle)]
176 pub extern "C" fn wasm_frame_func_index(frame: &wasm_frame_t<'_>) -> u32 {
177     frame.trace.frames()[frame.idx].func_index()
178 }
179 
180 #[unsafe(no_mangle)]
181 pub extern "C" fn wasmtime_frame_func_name<'a>(
182     frame: &'a wasm_frame_t<'_>,
183 ) -> Option<&'a wasm_name_t> {
184     frame
185         .func_name
186         .get_or_init(|| {
187             frame.trace.frames()[frame.idx]
188                 .func_name()
189                 .map(|s| wasm_name_t::from(s.to_string().into_bytes()))
190         })
191         .as_ref()
192 }
193 
194 #[unsafe(no_mangle)]
195 pub extern "C" fn wasmtime_frame_module_name<'a>(
196     frame: &'a wasm_frame_t<'_>,
197 ) -> Option<&'a wasm_name_t> {
198     frame
199         .module_name
200         .get_or_init(|| {
201             frame.trace.frames()[frame.idx]
202                 .module()
203                 .name()
204                 .map(|s| wasm_name_t::from(s.to_string().into_bytes()))
205         })
206         .as_ref()
207 }
208 
209 #[unsafe(no_mangle)]
210 pub extern "C" fn wasm_frame_func_offset(frame: &wasm_frame_t<'_>) -> usize {
211     frame.trace.frames()[frame.idx]
212         .func_offset()
213         .unwrap_or(usize::MAX)
214 }
215 
216 #[unsafe(no_mangle)]
217 pub extern "C" fn wasm_frame_instance(_arg1: *const wasm_frame_t<'_>) -> *mut wasm_instance_t {
218     unimplemented!("wasm_frame_instance")
219 }
220 
221 #[unsafe(no_mangle)]
222 pub extern "C" fn wasm_frame_module_offset(frame: &wasm_frame_t<'_>) -> usize {
223     frame.trace.frames()[frame.idx]
224         .module_offset()
225         .unwrap_or(usize::MAX)
226 }
227 
228 #[unsafe(no_mangle)]
229 pub extern "C" fn wasm_frame_copy<'a>(frame: &wasm_frame_t<'a>) -> Box<wasm_frame_t<'a>> {
230     Box::new(frame.clone())
231 }
232