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