cli: re-introduce create-exe functionality

lib/cli/src/commands/wasmer_create_exe_main.c

@@ -0,0 +1,176 @@
+
+#include "wasmer.h"
+//#include "my_wasm.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define own
+
+// TODO: make this define templated so that the Rust code can toggle it on/off
+#define WASI
+
+extern size_t WASMER_MODULE_LENGTH asm("WASMER_MODULE_LENGTH");
+extern char WASMER_MODULE_DATA asm("WASMER_MODULE_DATA");
+
+static void print_wasmer_error() {
+  int error_len = wasmer_last_error_length();
+  printf("Error len: `%d`\n", error_len);
+  char *error_str = (char *)malloc(error_len);
+  wasmer_last_error_message(error_str, error_len);
+  printf("%s\n", error_str);
+  free(error_str);
+}
+
+#ifdef WASI
+static void pass_mapdir_arg(wasi_config_t *wasi_config, char *mapdir) {
+  int colon_location = strchr(mapdir, ':') - mapdir;
+  if (colon_location == 0) {
+    // error malformed argument
+    fprintf(stderr, "Expected mapdir argument of the form alias:directory\n");
+    exit(-1);
+  }
+
+  char *alias = (char *)malloc(colon_location + 1);
+  memcpy(alias, mapdir, colon_location);
+  alias[colon_location] = '\0';
+
+  int dir_len = strlen(mapdir) - colon_location;
+  char *dir = (char *)malloc(dir_len + 1);
+  memcpy(dir, &mapdir[colon_location + 1], dir_len);
+  dir[dir_len] = '\0';
+
+  wasi_config_mapdir(wasi_config, alias, dir);
+  free(alias);
+  free(dir);
+}
+
+// We try to parse out `--dir` and `--mapdir` ahead of time and process those
+// specially. All other arguments are passed to the guest program.
+static void handle_arguments(wasi_config_t *wasi_config, int argc,
+                             char *argv[]) {
+  for (int i = 1; i < argc; ++i) {
+    // We probably want special args like `--dir` and `--mapdir` to not be
+    // passed directly
+    if (strcmp(argv[i], "--dir") == 0) {
+      // next arg is a preopen directory
+      if ((i + 1) < argc) {
+        i++;
+        wasi_config_preopen_dir(wasi_config, argv[i]);
+      } else {
+        fprintf(stderr, "--dir expects a following argument specifying which "
+                        "directory to preopen\n");
+        exit(-1);
+      }
+    } else if (strcmp(argv[i], "--mapdir") == 0) {
+      // next arg is a mapdir
+      if ((i + 1) < argc) {
+        i++;
+        pass_mapdir_arg(wasi_config, argv[i]);
+      } else {
+        fprintf(stderr,
+                "--mapdir expects a following argument specifying which "
+                "directory to preopen in the form alias:directory\n");
+        exit(-1);
+      }
+    } else if (strncmp(argv[i], "--dir=", strlen("--dir=")) == 0) {
+      // this arg is a preopen dir
+      char *dir = argv[i] + strlen("--dir=");
+      wasi_config_preopen_dir(wasi_config, dir);
+    } else if (strncmp(argv[i], "--mapdir=", strlen("--mapdir=")) == 0) {
+      // this arg is a mapdir
+      char *mapdir = argv[i] + strlen("--mapdir=");
+      pass_mapdir_arg(wasi_config, mapdir);
+    } else {
+      // guest argument
+      wasi_config_arg(wasi_config, argv[i]);
+    }
+  }
+}
+#endif
+
+int main(int argc, char *argv[]) {
+  wasm_config_t *config = wasm_config_new();
+  wasm_engine_t *engine = wasm_engine_new_with_config(config);
+  wasm_store_t *store = wasm_store_new(engine);
+
+  wasm_byte_vec_t module_byte_vec = {
+    .size = WASMER_MODULE_LENGTH,
+    .data = (const char*)&WASMER_MODULE_DATA,
+  };
+  wasm_module_t *module = wasm_module_deserialize(store, &module_byte_vec);
+
+  if (!module) {
+    fprintf(stderr, "Failed to create module\n");
+    print_wasmer_error();
+    return -1;
+  }
+
+  // We have now finished the memory buffer book keeping and we have a valid
+  // Module.
+
+#ifdef WASI
+  wasi_config_t *wasi_config = wasi_config_new(argv[0]);
+  handle_arguments(wasi_config, argc, argv);
+
+  wasi_env_t *wasi_env = wasi_env_new(store, wasi_config);
+  if (!wasi_env) {
+    fprintf(stderr, "Error building WASI env!\n");
+    print_wasmer_error();
+    return 1;
+  }
+#endif
+
+  wasm_importtype_vec_t import_types;
+  wasm_module_imports(module, &import_types);
+
+  wasm_extern_vec_t imports;
+  wasm_extern_vec_new_uninitialized(&imports, import_types.size);
+  wasm_importtype_vec_delete(&import_types);
+
+#ifdef WASI
+  bool get_imports_result = wasi_get_imports(store, wasi_env, module, &imports);
+
+  if (!get_imports_result) {
+    fprintf(stderr, "Error getting WASI imports!\n");
+    print_wasmer_error();
+
+    return 1;
+  }
+#endif
+
+  wasm_instance_t *instance = wasm_instance_new(store, module, &imports, NULL);
+
+  if (!instance) {
+    fprintf(stderr, "Failed to create instance\n");
+    print_wasmer_error();
+    return -1;
+  }
+
+#ifdef WASI
+  own wasm_func_t *start_function = wasi_get_start_function(instance);
+  if (!start_function) {
+    fprintf(stderr, "`_start` function not found\n");
+    print_wasmer_error();
+    return -1;
+  }
+
+  wasm_val_vec_t args = WASM_EMPTY_VEC;
+  wasm_val_vec_t results = WASM_EMPTY_VEC;
+  own wasm_trap_t *trap = wasm_func_call(start_function, &args, &results);
+  if (trap) {
+    fprintf(stderr, "Trap is not NULL: TODO:\n");
+    return -1;
+  }
+  wasi_env_delete(wasi_env);
+#endif
+
+  // TODO: handle non-WASI start (maybe with invoke?)
+
+  wasm_instance_delete(instance);
+  wasm_module_delete(module);
+  wasm_store_delete(store);
+  wasm_engine_delete(engine);
+  return 0;
+}