FIFO stream is automatically closed when receiving data on Linux (and not on macOS)

[Bacto]

Version

16 & 18 at least

Platform

Linux and macOS

Subsystem

No response

What steps will reproduce the bug?

Hi,

I'm trying to read from a FIFO file using Node.js but I get 2 different behaviors on macOS and Linux.

On macOS, everything seems working as expected.
On Linux, when a chunk of data is received the FIFO stream is automatically closed.

Here is the code example:

const fs = require('fs');
const net = require('net');
const child_process = require('child_process');

const filename = 'test';


// Clean and create FIFO
fs.rmSync(filename, { force: true });
child_process.execSync(`mkfifo -m 622 ${filename}`);


// Open FIFO
// See https://github.com/nodejs/node/issues/23220#issuecomment-426345872
const fd = fs.openSync(filename, fs.constants.O_RDONLY | fs.constants.O_NONBLOCK);
const fifoStream = new net.Socket({ fd });


// Handle FIFO events
fifoStream.on('data', data => console.log('Data received in FIFO stream:', data.toString()));
fifoStream.on('close', () => console.log('FIFO stream closed'));


// Send data to FIFO
setInterval(
  () => {
    console.log('Writing data "Test" to FIFO');
    fs.writeFileSync(filename, 'Test');
  },
  1000
);

On macOS (M1, Node.js v16.13.2, v16.17.1 and v18.12.0), the FIFO stream stays opened and continues to show data received:

$ node test.js
Writing data "Test" to FIFO
Data received in FIFO stream: Test
Writing data "Test" to FIFO
Data received in FIFO stream: Test
Writing data "Test" to FIFO
Data received in FIFO stream: Test
Writing data "Test" to FIFO
Data received in FIFO stream: Test
Writing data "Test" to FIFO
Data received in FIFO stream: Test
Writing data "Test" to FIFO
Data received in FIFO stream: Test

On Linux (Ubuntu 22.10 with Node.js v18.7.0 and Alpine Linux 3.16.2 with Node.js v16.17.1), the stream close on first chunk of data received:

# node test.js
Writing data "Test" to FIFO
Data received in FIFO stream: Test
FIFO stream closed

How often does it reproduce? Is there a required condition?

Each time on Linux

What is the expected behavior?

Shouldn't close the FIFO stream when a chunk is received

What do you see instead?

Closes the FIFO stream

Additional information

No response

[bnoordhuis]

See #23220 (comment) from the same issue you linked to. The behavior of a FIFO in non-blocking mode is not well-defined, it doesn't even have to behave the same on different versions of the same operating system.

[Bacto]

Thanks for the hint @bnoordhuis :)