node-syscall-napi

Node.js module to perform synchronous syscalls

About

This module allows to execute syscalls on linux based systems. NAPI is being used to stay ABI compatible with future Node.js versions. The focus of this module is not (yet) performance, but providing a clear interface to the linux kernel.

Previously this module supported asynchronous operation, which turned out not to work as expected. Although it would be possible, currently this is not supported anymore. If you need to execute long running syscalls in parallel, use Workers.

Requirements

• Node.js >= 20, might work on older

Installation

npm install syscall-napi

or

yarn install syscall-napi

API

syscall({ syscallNumber: bigint, args: (bigint | Uint8Array)[] }) => { errno: undefined, ret: BigInt } | { errno: number, ret: undefined }

Supported argument types:

• BigInt arguments are converted to native integers
• Buffer arguments are converted to the address of the buffer in memory. Be aware that passing buffers of wrong sizes (i.e. smaller than the kernel expects) leads to undefined behaviour as it may overwrite vital data or crash the application.

In case of an error the promise is rejected with an error object.

For params see man 2 syscall.

syscallNumbers.{syscall}

This module provides syscall numbers (e.g. getpid) that are defined in uapi/asm-generic/unistd.h in the linux kernel.

Minimal example

import { syscall, syscallNumbers } from "syscall-napi";

const { errno, ret: pid } = syscall({
  syscallNumber: syscallNumbers.getpid,
  args: []
});

if (errno === undefined) {
  console.log(`pid = ${pid}`);
} else {
  console.log(`errno = ${errno}`);
}