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 wasm_store_t *store = wasm_store_new(engine); 65 assert(store != NULL); 66 67 // Create our interrupt handle we'll use later 68 wasmtime_interrupt_handle_t *handle = wasmtime_interrupt_handle_new(store); 69 assert(handle != NULL); 70 71 // Read our input file, which in this case is a wasm text file. 72 FILE* file = fopen("examples/interrupt.wat", "r"); 73 assert(file != NULL); 74 fseek(file, 0L, SEEK_END); 75 size_t file_size = ftell(file); 76 fseek(file, 0L, SEEK_SET); 77 wasm_byte_vec_t wat; 78 wasm_byte_vec_new_uninitialized(&wat, file_size); 79 assert(fread(wat.data, file_size, 1, file) == 1); 80 fclose(file); 81 82 // Parse the wat into the binary wasm format 83 wasm_byte_vec_t wasm; 84 wasmtime_error_t *error = wasmtime_wat2wasm(&wat, &wasm); 85 if (error != NULL) 86 exit_with_error("failed to parse wat", error, NULL); 87 wasm_byte_vec_delete(&wat); 88 89 // Now that we've got our binary webassembly we can compile our module. 90 wasm_module_t *module = NULL; 91 wasm_trap_t *trap = NULL; 92 wasm_instance_t *instance = NULL; 93 wasm_extern_vec_t imports = WASM_EMPTY_VEC; 94 error = wasmtime_module_new(engine, &wasm, &module); 95 wasm_byte_vec_delete(&wasm); 96 if (error != NULL) 97 exit_with_error("failed to compile module", error, NULL); 98 error = wasmtime_instance_new(store, module, &imports, &instance, &trap); 99 if (instance == NULL) 100 exit_with_error("failed to instantiate", error, trap); 101 102 // Lookup our `run` export function 103 wasm_extern_vec_t externs; 104 wasm_instance_exports(instance, &externs); 105 assert(externs.size == 1); 106 wasm_func_t *run = wasm_extern_as_func(externs.data[0]); 107 assert(run != NULL); 108 109 // Spawn a thread to send us an interrupt after a period of time. 110 spawn_interrupt(handle); 111 112 // And call it! 113 printf("Entering infinite loop...\n"); 114 wasm_val_vec_t args_vec = WASM_EMPTY_VEC; 115 wasm_val_vec_t results_vec = WASM_EMPTY_VEC; 116 error = wasmtime_func_call(run, &args_vec, &results_vec, &trap); 117 assert(error == NULL); 118 assert(trap != NULL); 119 printf("Got a trap!...\n"); 120 121 // `trap` can be inspected here to see the trap message has an interrupt in it 122 123 wasm_trap_delete(trap); 124 wasm_extern_vec_delete(&externs); 125 wasm_instance_delete(instance); 126 wasm_module_delete(module); 127 wasm_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