Need help with accessing WASI API

[adityaprasadv1]

• Node.js Version: 13.5.0
• OS: Windows 10
• Module: WASI

In the given example, can we get the source code of the wasm file.

[gireeshpunathil]

cc @nodejs/wasi

[gengjiawen]

You can try the wasm files here: nodejs/node@09b1228#diff-5a38107d7dabcebcb78af5059b242974.

Change the related name should work.

[adityaprasadv1]

We compiled the following C code using WasmExplorer

#include <assert.h>
#include <stdio.h>
#include <string.h>

static char* message = "hello, file!";

int main() {
  FILE* file = fopen("C:/test.txt", "w");
  assert(file != NULL);

  int nwritten = fprintf(file, "%s", message);
  assert(nwritten == strlen(message));
  int r = fclose(file);
  assert(r == 0);
}

index.js

const fs = require('fs');
const { WASI } = require('wasi');
const wasi = new WASI({
  args: process.argv,
  env: process.env,
  preopens: {
    '/sandbox': '.'
  }
});
const importObject = { wasi_unstable: wasi.wasiImport };

(async () => {
  const wasm = await WebAssembly.compile(fs.readFileSync('./test.wasm'));
  const instance = await WebAssembly.instantiate(wasm, importObject);

  wasi.start(instance);
})();

We get the following error,

> node --experimental-wasi-unstable-preview0 --experimental-wasm-bigint index.js

npm[7056]: c:\ws\src\node_wasi.cc:92: Assertion `(uvwasi_init(&uvw_, options)) == (0)' failed.
 1: 00007FF7F21CDCDF napi_wrap+126063
 2: 00007FF7F216D156 v8::base::CPU::has_sse+36198
 3: 00007FF7F216D473 v8::base::CPU::has_sse+36995
 4: 00007FF7F20F9B46 v8::internal::wasm::JSToWasmWrapperCompilationUnit::~JSToWasmWrapperCompilationUnit+10886
 5: 00007FF7F20FEEE0 v8::internal::wasm::JSToWasmWrapperCompilationUnit::~JSToWasmWrapperCompilationUnit+32288
 6: 00007FF7F2948360 v8::internal::Builtins::builtin_handle+326608
 7: 00007FF7F294751C v8::internal::Builtins::builtin_handle+322956
 8: 00007FF7F2947BB2 v8::internal::Builtins::builtin_handle+324642
 9: 00007FF7F29479EE v8::internal::Builtins::builtin_handle+324190
10: 00007FF7F2DDECAD v8::internal::SetupIsolateDelegate::SetupHeap+517677
11: 00007FF7F2D66331 v8::internal::SetupIsolateDelegate::SetupHeap+23729
12: 00007FF7F2E4A32B v8::internal::SetupIsolateDelegate::SetupHeap+957611
13: 00007FF7F2D6A4EB v8::internal::SetupIsolateDelegate::SetupHeap+40555
14: 00007FF7F2D66237 v8::internal::SetupIsolateDelegate::SetupHeap+23479
15: 00007FF7F2E4A32B v8::internal::SetupIsolateDelegate::SetupHeap+957611
16: 00007FF7F2D6A4EB v8::internal::SetupIsolateDelegate::SetupHeap+40555
17: 00007FF7F2D6A4EB v8::internal::SetupIsolateDelegate::SetupHeap+40555
18: 00007FF7F2D6A4EB v8::internal::SetupIsolateDelegate::SetupHeap+40555
19: 00007FF7F2D6A4EB v8::internal::SetupIsolateDelegate::SetupHeap+40555
20: 00007FF7F2D6A4EB v8::internal::SetupIsolateDelegate::SetupHeap+40555
21: 00007FF7F2D6A4EB v8::internal::SetupIsolateDelegate::SetupHeap+40555
22: 00007FF7F2D6A4EB v8::internal::SetupIsolateDelegate::SetupHeap+40555
23: 00007FF7F2D6804E v8::internal::SetupIsolateDelegate::SetupHeap+31182
24: 00007FF7F2D67C3C v8::internal::SetupIsolateDelegate::SetupHeap+30140
25: 00007FF7F28A0402 v8::internal::Execution::CallWasm+1410
26: 00007FF7F289FD79 v8::internal::Execution::Call+185
27: 00007FF7F2973860 v8::Function::Call+608
28: 00007FF7F2195411 node::Start+1153
29: 00007FF7F2195647 node::Start+1719
30: 00007FF7F219463A node::LoadEnvironment+26
31: 00007FF7F2138392 v8::internal::AsmJsScanner::GetIdentifierString+29458
32: 00007FF7F21950B0 node::Start+288
33: 00007FF7F2046ABC RC4_options+340412
34: 00007FF7F2E9C5D8 v8::internal::SetupIsolateDelegate::SetupHeap+1294168
35: 00007FFED36A7BD4 BaseThreadInitThunk+20
36: 00007FFED382CED1 RtlUserThreadStart+33
npm ERR! code ELIFECYCLE
npm ERR! errno 134
npm ERR! node-wasi-example@1.0.0 start: `node --experimental-wasi-unstable-preview0 --experimental-wasm-bigint index.js`npm ERR! Exit status 134
npm ERR!
npm ERR! Failed at the node-wasi-example@1.0.0 start script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
npm WARN Local package.json exists, but node_modules missing, did you mean to install?

npm ERR! A complete log of this run can be found in:
npm ERR!     C:\Users\Aditya\AppData\Roaming\npm-cache\_logs\2020-01-07T14_16_56_915Z-debug.log

Thank you.

[legendecas]

AFAICT, WasmExplorer doesn't emit wasm that using WASI APIs. And the assertion is related to nodejs/node#31076, which has not yet been released.

[legendecas]

Note that you could try toolchains provided in https://github.com/CraneStation/wasi-sdk to compile a C/C++ project to wasm-wasi target, which can be used with Node.js wasi module.

[gengjiawen]

you need absolute path in preopens

[PoojaDurgad]

ping , @adityaprasadv1 - were you able to follow the suggestions? or still outstanding?

[gireeshpunathil]

answered, closing. feel free to re-open if it is outstanding