f94db6556c
* Update WebAssembly C API submodule to latest commit. This commit updates the WebAssembly C API submodule (for `wasm.h`) to the latest commit out of master. This fixes the behavior of `wasm_name_new_from_string` such that it no longer copies the null character into the name, which caused unexpected failures when using the Wasmtime linker as imports wouldn't resolve when the null was present. Along with this change were breaking changes to `wasm_func_call`, the host callback signatures, and `wasm_instance_new` to take a vector type instead of a pointer to an unsized array. As a result, Wasmtime language bindings based on the C API will need to be updated once this change is pulled in. Fixes #2211. Fixes #2131. * Update Doxygen comments for wasm.h changes.
122 lines
3.7 KiB
C
122 lines
3.7 KiB
C
/*
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Example of instantiating a WebAssembly which uses WASI imports.
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You can compile and run this example on Linux with:
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cargo build --release -p wasmtime-c-api
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cc examples/wasi/main.c \
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-I crates/c-api/include \
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-I crates/c-api/wasm-c-api/include \
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target/release/libwasmtime.a \
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-lpthread -ldl -lm \
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-o wasi
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./wasi
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Note that on Windows and macOS the command will be similar, but you'll need
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to tweak the `-lpthread` and such annotations.
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*/
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#include <assert.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <wasm.h>
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#include <wasi.h>
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#include <wasmtime.h>
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#define MIN(a, b) ((a) < (b) ? (a) : (b))
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static void exit_with_error(const char *message, wasmtime_error_t *error, wasm_trap_t *trap);
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int main() {
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int ret = 0;
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// Set up our context
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wasm_engine_t *engine = wasm_engine_new();
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assert(engine != NULL);
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wasm_store_t *store = wasm_store_new(engine);
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assert(store != NULL);
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wasm_byte_vec_t wasm;
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// Load our input file to parse it next
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FILE* file = fopen("target/wasm32-wasi/debug/wasi.wasm", "rb");
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if (!file) {
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printf("> Error loading file!\n");
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exit(1);
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}
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fseek(file, 0L, SEEK_END);
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size_t file_size = ftell(file);
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wasm_byte_vec_new_uninitialized(&wasm, file_size);
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fseek(file, 0L, SEEK_SET);
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if (fread(wasm.data, file_size, 1, file) != 1) {
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printf("> Error loading module!\n");
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exit(1);
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}
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fclose(file);
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// Compile our modules
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wasm_module_t *module = NULL;
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wasmtime_error_t *error = wasmtime_module_new(engine, &wasm, &module);
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if (!module)
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exit_with_error("failed to compile module", error, NULL);
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wasm_byte_vec_delete(&wasm);
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// Instantiate wasi
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wasi_config_t *wasi_config = wasi_config_new();
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assert(wasi_config);
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wasi_config_inherit_argv(wasi_config);
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wasi_config_inherit_env(wasi_config);
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wasi_config_inherit_stdin(wasi_config);
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wasi_config_inherit_stdout(wasi_config);
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wasi_config_inherit_stderr(wasi_config);
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wasm_trap_t *trap = NULL;
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wasi_instance_t *wasi = wasi_instance_new(store, "wasi_snapshot_preview1", wasi_config, &trap);
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if (wasi == NULL)
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exit_with_error("failed to instantiate WASI", NULL, trap);
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wasmtime_linker_t *linker = wasmtime_linker_new(store);
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error = wasmtime_linker_define_wasi(linker, wasi);
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if (error != NULL)
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exit_with_error("failed to link wasi", error, NULL);
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// Instantiate the module
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wasm_name_t empty;
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wasm_name_new_from_string(&empty, "");
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wasm_instance_t *instance = NULL;
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error = wasmtime_linker_module(linker, &empty, module);
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if (error != NULL)
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exit_with_error("failed to instantiate module", error, NULL);
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// Run it.
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wasm_func_t* func;
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wasmtime_linker_get_default(linker, &empty, &func);
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if (error != NULL)
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exit_with_error("failed to locate default export for module", error, NULL);
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wasm_val_vec_t args_vec = WASM_EMPTY_VEC;
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wasm_val_vec_t results_vec = WASM_EMPTY_VEC;
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error = wasmtime_func_call(func, &args_vec, &results_vec, &trap);
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if (error != NULL)
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exit_with_error("error calling default export", error, trap);
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// Clean up after ourselves at this point
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wasm_name_delete(&empty);
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wasm_module_delete(module);
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wasm_store_delete(store);
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wasm_engine_delete(engine);
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return 0;
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}
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static void exit_with_error(const char *message, wasmtime_error_t *error, wasm_trap_t *trap) {
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fprintf(stderr, "error: %s\n", message);
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wasm_byte_vec_t error_message;
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if (error != NULL) {
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wasmtime_error_message(error, &error_message);
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wasmtime_error_delete(error);
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} else {
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wasm_trap_message(trap, &error_message);
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wasm_trap_delete(trap);
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}
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fprintf(stderr, "%.*s\n", (int) error_message.size, error_message.data);
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wasm_byte_vec_delete(&error_message);
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exit(1);
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}
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