1 /* 2 Example of instantiating of the WebAssembly module and invoking its exported 3 function. 4 5 You can compile and run this example on Linux with: 6 7 cargo build --release -p wasmtime-c-api 8 cc examples/interrupt.c \ 9 -I crates/c-api/include \ 10 -I crates/c-api/wasm-c-api/include \ 11 target/release/libwasmtime.a \ 12 -lpthread -ldl -lm \ 13 -o interrupt 14 ./interrupt 15 16 Note that on Windows and macOS the command will be similar, but you'll need 17 to tweak the `-lpthread` and such annotations as well as the name of the 18 `libwasmtime.a` file on Windows. 19 */ 20 21 #include <assert.h> 22 #include <stdio.h> 23 #include <stdlib.h> 24 #include <wasm.h> 25 #include <wasmtime.h> 26 27 #ifdef _WIN32 28 static void spawn_interrupt(wasmtime_interrupt_handle_t *handle) { 29 wasmtime_interrupt_handle_interrupt(handle); 30 wasmtime_interrupt_handle_delete(handle); 31 } 32 #else 33 #include <pthread.h> 34 #include <time.h> 35 36 static void* helper(void *_handle) { 37 wasmtime_interrupt_handle_t *handle = _handle; 38 struct timespec sleep_dur; 39 sleep_dur.tv_sec = 1; 40 sleep_dur.tv_nsec = 0; 41 nanosleep(&sleep_dur, NULL); 42 printf("Sending an interrupt\n"); 43 wasmtime_interrupt_handle_interrupt(handle); 44 wasmtime_interrupt_handle_delete(handle); 45 return 0; 46 } 47 48 static void spawn_interrupt(wasmtime_interrupt_handle_t *handle) { 49 pthread_t child; 50 int rc = pthread_create(&child, NULL, helper, handle); 51 assert(rc == 0); 52 } 53 #endif 54 55 static void exit_with_error(const char *message, wasmtime_error_t *error, wasm_trap_t *trap); 56 57 int main() { 58 // Create a `wasm_store_t` with interrupts enabled 59 wasm_config_t *config = wasm_config_new(); 60 assert(config != NULL); 61 wasmtime_config_interruptable_set(config, true); 62 wasm_engine_t *engine = wasm_engine_new_with_config(config); 63 assert(engine != NULL); 64 wasmtime_store_t *store = wasmtime_store_new(engine, NULL, NULL); 65 assert(store != NULL); 66 wasmtime_context_t *context = wasmtime_store_context(store); 67 68 // Create our interrupt handle we'll use later 69 wasmtime_interrupt_handle_t *handle = wasmtime_interrupt_handle_new(context); 70 assert(handle != NULL); 71 72 // Read our input file, which in this case is a wasm text file. 73 FILE* file = fopen("examples/interrupt.wat", "r"); 74 assert(file != NULL); 75 fseek(file, 0L, SEEK_END); 76 size_t file_size = ftell(file); 77 fseek(file, 0L, SEEK_SET); 78 wasm_byte_vec_t wat; 79 wasm_byte_vec_new_uninitialized(&wat, file_size); 80 assert(fread(wat.data, file_size, 1, file) == 1); 81 fclose(file); 82 83 // Parse the wat into the binary wasm format 84 wasm_byte_vec_t wasm; 85 wasmtime_error_t *error = wasmtime_wat2wasm(wat.data, wat.size, &wasm); 86 if (error != NULL) 87 exit_with_error("failed to parse wat", error, NULL); 88 wasm_byte_vec_delete(&wat); 89 90 // Now that we've got our binary webassembly we can compile our module. 91 wasmtime_module_t *module = NULL; 92 error = wasmtime_module_new(engine, (uint8_t*) wasm.data, wasm.size, &module); 93 wasm_byte_vec_delete(&wasm); 94 if (error != NULL) 95 exit_with_error("failed to compile module", error, NULL); 96 97 wasm_trap_t *trap = NULL; 98 wasmtime_instance_t instance; 99 error = wasmtime_instance_new(context, module, NULL, 0, &instance, &trap); 100 if (error != NULL || trap != NULL) 101 exit_with_error("failed to instantiate", error, trap); 102 wasmtime_module_delete(module); 103 104 // Lookup our `run` export function 105 wasmtime_extern_t run; 106 bool ok = wasmtime_instance_export_get(context, &instance, "run", 3, &run); 107 assert(ok); 108 assert(run.kind == WASMTIME_EXTERN_FUNC); 109 110 // Spawn a thread to send us an interrupt after a period of time. 111 spawn_interrupt(handle); 112 113 // And call it! 114 printf("Entering infinite loop...\n"); 115 error = wasmtime_func_call(context, &run.of.func, NULL, 0, NULL, 0, &trap); 116 assert(error == NULL); 117 assert(trap != NULL); 118 printf("Got a trap!...\n"); 119 120 // `trap` can be inspected here to see the trap message has an interrupt in it 121 wasmtime_trap_code_t code; 122 ok = wasmtime_trap_code(trap, &code); 123 assert(ok); 124 assert(code == WASMTIME_TRAP_CODE_INTERRUPT); 125 wasm_trap_delete(trap); 126 127 wasmtime_store_delete(store); 128 wasm_engine_delete(engine); 129 return 0; 130 } 131 132 static void exit_with_error(const char *message, wasmtime_error_t *error, wasm_trap_t *trap) { 133 fprintf(stderr, "error: %s\n", message); 134 wasm_byte_vec_t error_message; 135 if (error != NULL) { 136 wasmtime_error_message(error, &error_message); 137 wasmtime_error_delete(error); 138 } else { 139 wasm_trap_message(trap, &error_message); 140 wasm_trap_delete(trap); 141 } 142 fprintf(stderr, "%.*s\n", (int) error_message.size, error_message.data); 143 wasm_byte_vec_delete(&error_message); 144 exit(1); 145 } 146