Add Makefile with build and test targets

.gitignore

@@ -1 +0,0 @@
-build/

Makefile

@@ -1,24 +1,56 @@
-SHELL		:= /bin/bash
+SHELL  := /bin/bash
-CC			:= cc
+CC     := cc
-MKDIR		:= mkdir
+CFLAGS := -Wall -O2
-CFLAGS		:= -Wall -Werror -Os
+TARGET := fa2json
-BUILD_DIR	:= build
+SRCS   := fs-watcher.c json-writer.c
-TARGET		:= $(BUILD_DIR)/fa2json
-SRCS		:= fs-watcher.c json-writer.c
 
-.PHONY: all test dev clean
+.PHONY: all test clean
 
 all: $(TARGET)
 
 $(TARGET): $(SRCS)
-	$(MKDIR) -p $(BUILD_DIR)
 	$(CC) $(CFLAGS) -o $@ $^
 
+# Requires root (fanotify FID + mount needs CAP_SYS_ADMIN).
+# Loop device and mount are cleaned up automatically on exit.
+# If the test aborts unexpectedly, check: losetup -l and /proc/mounts
 test: $(TARGET)
-	node test/test.mjs
+	@set -euo pipefail; \
-
+	IMG=""; MNTDIR=""; LOOPDEV=""; FA2JSON_PID=""; \
-dev: $(TARGET)
+	cleanup() { \
-	node test/dev.mjs $(ARGS)
+		[ -n "$$FA2JSON_PID" ] && { kill "$$FA2JSON_PID" 2>/dev/null; wait "$$FA2JSON_PID" 2>/dev/null || true; }; \
+		[ -n "$$MNTDIR" ]      && umount "$$MNTDIR"    2>/dev/null || true; \
+		[ -n "$$LOOPDEV" ]     && losetup -d "$$LOOPDEV" 2>/dev/null || true; \
+		[ -n "$$IMG" ]         && rm -f "$$IMG"; \
+		[ -n "$$MNTDIR" ]      && rmdir "$$MNTDIR"     2>/dev/null || true; \
+	}; \
+	trap cleanup EXIT; \
+	IMG=$$(mktemp /tmp/fa2json-test-XXXXXX.img); \
+	MNTDIR=$$(mktemp -d /tmp/fa2json-mnt-XXXXXX); \
+	echo "--- Creating 10M ext4 image ---"; \
+	dd if=/dev/zero of="$$IMG" bs=1M count=10 status=none; \
+	mkfs.ext4 -q "$$IMG"; \
+	LOOPDEV=$$(losetup --find --show "$$IMG"); \
+	mount "$$LOOPDEV" "$$MNTDIR"; \
+	echo "--- Starting fa2json on $$MNTDIR ---"; \
+	./$(TARGET) "$$MNTDIR" & FA2JSON_PID=$$!; \
+	sleep 0.3; \
+	echo "--- Filesystem operations ---"; \
+	mkdir "$$MNTDIR/dir_a"; \
+	touch "$$MNTDIR/file_a.txt"; \
+	echo "content" >> "$$MNTDIR/file_a.txt"; \
+	mkdir "$$MNTDIR/dir_b"; \
+	touch "$$MNTDIR/dir_b/nested.txt"; \
+	mv "$$MNTDIR/file_a.txt" "$$MNTDIR/file_b.txt"; \
+	mv "$$MNTDIR/dir_b" "$$MNTDIR/dir_a/dir_b_moved"; \
+	chmod 600 "$$MNTDIR/file_b.txt"; \
+	touch -m "$$MNTDIR/file_b.txt"; \
+	chmod 755 "$$MNTDIR/dir_a"; \
+	rm "$$MNTDIR/file_b.txt"; \
+	rm "$$MNTDIR/dir_a/dir_b_moved/nested.txt"; \
+	rm -rf "$$MNTDIR/dir_a"; \
+	sleep 0.3; \
+	echo "--- Done ---"
 
 clean:
-	rm -rf $(BUILD_DIR)
+	rm -f $(TARGET)

fs-watcher.c

@@ -58,7 +58,7 @@ static void handle_events(int fafd, int mount_fd) {
 				clock_gettime(CLOCK_MONOTONIC, &mono);
 				clock_gettime(CLOCK_REALTIME, &wall);
 
-				fprintf(stdout, "{\"ts\": [%li, %li, %li, %li]", wall.tv_sec, wall.tv_nsec, mono.tv_sec, mono.tv_nsec);
+				fprintf(stdout, "{\"ts\": [%i, %i, %i, %i]", wall.tv_sec, wall.tv_nsec, mono.tv_sec, mono.tv_nsec);
 
 				char *ptr = (char *)(metadata + 1);
 				char *end = (char *)metadata + metadata->event_len;
@@ -98,7 +98,7 @@ static void handle_events(int fafd, int mount_fd) {
 				}
 
 				if (entry_index++) { fprintf(stdout, ", "); }
-				fprintf(stdout, ", \"mask\": %lli}\n", metadata->mask);
+				fprintf(stdout, ", \"mask\": %i}\n", metadata->mask);
 
 				metadata = FAN_EVENT_NEXT(metadata, size);
 

test/Manual experiment.md

@@ -1,82 +0,0 @@
-## Manual experiment
-
-> [!NOTE]
-> This manual experiment shows how we can do the testing (teardown not included). Note that we don't need the `losetup`-stuff, we know where everything is.
-
-### Compile
-```sh
-gcc fs-watcher.c json-writer.c -o fa2json
-```
-### Create image file
-```sh
-mktemp /tmp/fa2json-test-XXXXXX.img
-```
-
-```text
-/tmp/fa2json-test-UrwpOb.img
-```
-
-```sh
-truncate -s 10M /tmp/fa2json-test-UrwpOb.img
-```
-
-```sh
-mkfs.ext4 /tmp/fa2json-test-UrwpOb.img
-```
-
-```text
-mke2fs 1.47.3 (8-Jul-2025)
-Discarding device blocks: done
-Creating filesystem with 10240 1k blocks and 2560 inodes
-Filesystem UUID: 035c508e-dec0-4a21-a4d1-1efb6fa72415
-Superblock backups stored on blocks:
-        8193
-
-Allocating group tables: done
-Writing inode tables: done
-Creating journal (1024 blocks): done
-Writing superblocks and filesystem accounting information: done
-```
-
-
-### Create mount point
-
-```sh
-mktemp -d /tmp/fa2json-mnt-XXXXXX
-```
-
-```text
-/tmp/fa2json-mnt-ts2Dik
-```
-
-### Mount loop device
-```sh
-sudo mount /tmp/fa2json-test-UrwpOb.img /tmp/fa2json-mnt-ts2Dik/
-```
-
-> [!NOTE]
-> In a different terminal I now ran - but we could do this after `chown` or possibly `chown` + `sync`?
-> ```sh
-> fa2json /tmp/fa2json-mnt-ts2Dik
-> ```
-
-### Let current user own file system
-```sh
-sudo chown $(id -u) /tmp/fa2json-mnt-ts2Dik/
-```
-
-#### `fa2json` output
-```json
-{"ts": [1772658052, 704412412, 386988, 865842867], "name": "/tmp/fa2json-mnt-ts2Dik/.", "mask": 1073741828}
-```
-
-### Touch marker
-```sh
-touch /tmp/fa2json-mnt-ts2Dik/MARKER
-```
-
-#### `fa2json` output
-```json
-{"ts": [1772658064, 151070715, 387000, 312501190], "name": "/tmp/fa2json-mnt-ts2Dik/MARKER", "mask": 256}
-{"ts": [1772658064, 151099105, 387000, 312529600], "name": "/tmp/fa2json-mnt-ts2Dik/MARKER", "mask": 12}
-```

test/PLAN.md

@@ -1,123 +0,0 @@
-# fa2json Test Plan
-
-## Overview
-
-A Node.js test runner (`test/test.mjs`) that exercises `fa2json` against a
-temporary ext4 filesystem on a loop device. The test produces a single
-pass/fail result and cleans up after itself unconditionally.
-
-Requires root (`fanotify` FID reporting and `mount` both need `CAP_SYS_ADMIN`).
-
----
-
-## Files
-
-| File | Purpose |
-|---|---|
-| `test/test.mjs` | Test runner |
-| `Makefile` | `make test` target calls `sudo node test/test.mjs` |
-
----
-
-## Setup
-
-1. Create a temporary image file (`mktemp /tmp/fa2json-test-XXXXXX.img`)
-2. `truncate -s 10M` the image (sparse file, no need for `dd`)
-3. `mkfs.ext4` the image
-4. Create a temporary mount directory (`mktemp -d /tmp/fa2json-mnt-XXXXXX`)
-5. `sudo mount <img> <mntdir>` (no `losetup` needed — `mount` accepts image files directly)
-6. `sudo chown $(id -u) <mntdir>` to hand ownership to the current user
-7. `sync` to flush before fa2json starts listening
-8. `sudo` spawn `fa2json <mountpoint>` as a child process (needs `CAP_SYS_ADMIN`)
-9. Attach a `readline` interface to its stdout; parse each line as JSON and
-   push into an event buffer
-
-Steps 6 and 7 ensure the `chown` event never enters the fa2json stream, and
-all subsequent FS operations run unprivileged.
-
----
-
-## Teardown
-
-Runs unconditionally in a `finally` block:
-
-1. Kill the `fa2json` child process
-2. `sudo umount <mountpoint>`
-3. `rm` the image file
-4. `rmdir` the mount directory
-
----
-
-## Event Collection and the Marker Pattern
-
-`fa2json` runs continuously for the entire test. To associate events with
-specific operations, a marker file is used as a synchronisation barrier:
-
-1. Perform a filesystem operation
-2. Immediately `touch <mountpoint>/.marker_N` (where N is a counter)
-3. Wait until the event stream contains a CREATE event for `.marker_N`
-4. Collect all events since the previous marker — this batch belongs to the
-   current operation
-5. Assert on the batch, then advance the counter
-
-If a marker event never arrives the test hangs, which indicates a failure at
-the fa2json level itself.
-
----
-
-## Path Handling
-
-`fa2json` emits full paths including the mount prefix
-(e.g. `/tmp/fa2json-mnt-XXXXX/dir_a/file.txt`). The runner strips this prefix
-so assertions work against a virtual root:
-
-```
-/tmp/fa2json-mnt-XXXXX/dir_a/file.txt  →  /dir_a/file.txt
-```
-
----
-
-## Fanotify Mask Constants
-
-Relevant flags (bitwise, check with `mask & FLAG`):
-
-| Constant | Value | Meaning |
-|---|---|---|
-| `FAN_ATTRIB` | `0x4` | Metadata/attribute change |
-| `FAN_CLOSE_WRITE` | `0x8` | File closed after writing |
-| `FAN_CREATE` | `0x100` | File or directory created |
-| `FAN_DELETE` | `0x200` | File or directory deleted |
-| `FAN_RENAME` | `0x10000000` | Rename (has `old` and `new` fields) |
-| `FAN_ONDIR` | `0x40000000` | Event subject is a directory |
-
----
-
-## Operations and Expected Events
-
-Each row is one `doOp()` call. Events are matched by presence (not exact list)
-— extra events from ext4 internals are ignored.
-
-| Operation | Expected event(s) |
-|---|---|
-| `mkdir /dir_a` | CREATE \| ONDIR, name `/dir_a` |
-| `touch /file_a.txt` | CREATE, name `/file_a.txt` |
-| `echo "content" >> /file_a.txt` | CLOSE_WRITE, name `/file_a.txt` |
-| `mkdir /dir_b` | CREATE \| ONDIR, name `/dir_b` |
-| `touch /dir_b/nested.txt` | CREATE, name `/dir_b/nested.txt` |
-| `mv /file_a.txt /file_b.txt` | RENAME, old `/file_a.txt`, new `/file_b.txt` |
-| `mv /dir_b /dir_a/dir_b_moved` | RENAME \| ONDIR, old `/dir_b`, new `/dir_a/dir_b_moved` |
-| `chmod 600 /file_b.txt` | ATTRIB, name `/file_b.txt` |
-| `touch -m /file_b.txt` | ATTRIB, name `/file_b.txt` |
-| `chmod 755 /dir_a` | ATTRIB \| ONDIR, name `/dir_a` |
-| `rm /file_b.txt` | DELETE, name `/file_b.txt` |
-| `rm /dir_a/dir_b_moved/nested.txt` | DELETE, name `/dir_a/dir_b_moved/nested.txt` |
-| `rmdir /dir_a/dir_b_moved` | DELETE \| ONDIR, name `/dir_a/dir_b_moved` |
-| `rmdir /dir_a` | DELETE \| ONDIR, name `/dir_a` |
-
----
-
-## Pass / Fail
-
-- All assertions pass → print summary, `process.exit(0)`
-- Any assertion throws → print the failing operation, the expected event, and
-  the actual batch received, then `process.exit(1)`

test/dev.mjs

@@ -1,43 +0,0 @@
-#!/usr/bin/env node
-// Developer mode: set up loop device, stream fa2json output through jq,
-// tear down on exit. Optionally launch a terminal at the mount point.
-//
-// Usage:
-//   sudo node test/dev.mjs
-//   sudo node test/dev.mjs --terminal konsole
-//   sudo node test/dev.mjs --terminal "konsole -e bash"
-
-import { spawn } from 'node:child_process';
-import { createInterface } from 'node:readline';
-import { setup, spawnFa2json } from './lib/setup.mjs';
-
-const terminalArg = (() => {
-	const i = process.argv.indexOf('--terminal');
-	return i !== -1 ? process.argv.slice(i + 1).join(' ') : null;
-})();
-
-const { mnt, teardown } = await setup();
-console.error(`Mount point: ${mnt}`);
-
-// Pipe fa2json stdout through jq for pretty coloured output
-const fa2json = spawnFa2json(mnt);
-const jq = spawn('jq', ['-C', '--unbuffered', '.'], { stdio: ['pipe', 'inherit', 'inherit'] });
-fa2json.stdout.pipe(jq.stdin);
-
-fa2json.on('exit', async () => {
-	jq.stdin.end();
-	await teardown();
-	process.exit(0);
-});
-
-// Launch optional terminal at mount point
-if (terminalArg) {
-	const [cmd, ...args] = terminalArg.split(' ');
-	spawn(cmd, [...args, '--workdir', mnt], { detached: true, stdio: 'ignore' }).unref();
-	console.error(`Launched: ${terminalArg} --workdir ${mnt}`);
-}
-
-// Clean teardown on Ctrl+C
-process.on('SIGINT', async () => {
-	fa2json.kill('SIGTERM');
-});

test/lib/setup.mjs

@@ -1,31 +0,0 @@
-import { execFileSync, spawn } from 'node:child_process';
-import { join } from 'node:path';
-
-const FA2JSON = new URL('../../build/fa2json', import.meta.url).pathname;
-
-export async function setup() {
-	// Create image file and format
-	const img = execFileSync('mktemp', ['/tmp/fa2json-test-XXXXXX.img']).toString().trim();
-	execFileSync('truncate', ['-s', '10M', img]);
-	execFileSync('mkfs.ext4', ['-q', img]);
-
-	// Create mount point and mount
-	const mnt = execFileSync('mktemp', ['-d', '/tmp/fa2json-mnt-XXXXXX']).toString().trim();
-	execFileSync('sudo', ['mount', img, mnt]);
-
-	// Hand ownership to current user, then sync before fa2json starts
-	execFileSync('sudo', ['chown', String(process.getuid()), mnt]);
-	execFileSync('sync');
-
-	async function teardown() {
-		try { execFileSync('sudo', ['umount', mnt]); } catch {}
-		try { execFileSync('rm', ['-f', img]); } catch {}
-		try { execFileSync('rmdir', [mnt]); } catch {}
-	}
-
-	return { img, mnt, teardown };
-}
-
-export function spawnFa2json(mnt) {
-	return spawn('sudo', [FA2JSON, mnt], { stdio: ['ignore', 'pipe', 'inherit'] });
-}

test/test.mjs

@@ -1,119 +0,0 @@
-#!/usr/bin/env node
-// Automated test runner. Exit 0 = pass, exit 1 = fail.
-// Requires root (sudo) for mount and fa2json.
-
-import { createInterface } from 'node:readline';
-import { promises as fs } from 'node:fs';
-import { join } from 'node:path';
-import { setup, spawnFa2json } from './lib/setup.mjs';
-
-// Fanotify mask flags
-const FAN_ATTRIB      = 0x4;
-const FAN_CLOSE_WRITE = 0x8;
-const FAN_CREATE      = 0x100;
-const FAN_DELETE      = 0x200;
-const FAN_RENAME      = 0x10000000;
-const FAN_ONDIR       = 0x40000000;
-
-const { mnt, teardown } = await setup();
-const fa2json = spawnFa2json(mnt);
-
-// Event buffer and marker machinery
-const events = [];
-let markerResolve = null;
-let markerName = null;
-let markerCounter = 0;
-
-const rl = createInterface({ input: fa2json.stdout });
-rl.on('line', line => {
-	const event = JSON.parse(line);
-	// Strip mount prefix from all path fields
-	for (const key of ['name', 'old', 'new']) {
-		if (event[key]) event[key] = event[key].slice(mnt.length);
-	}
-	events.push(event);
-	if (markerResolve && event.name === `/.marker_${markerName}` && (event.mask & FAN_CREATE)) {
-		markerResolve();
-		markerResolve = null;
-	}
-});
-
-// Perform a FS operation, drop a marker, collect events up to that marker
-async function doOp(label, fn) {
-	const id = markerCounter++;
-	await fn();
-	await fs.writeFile(join(mnt, `.marker_${id}`), '');
-	await new Promise(resolve => {
-		markerName = id;
-		markerResolve = resolve;
-	});
-	// Collect all events since previous marker (excluding marker events themselves)
-	const batch = events.splice(0).filter(e => !e.name?.startsWith('/.marker_'));
-	return { label, batch };
-}
-
-function assert(label, batch, check) {
-	if (!check(batch)) {
-		console.error(`FAIL: ${label}`);
-		console.error('Batch:', JSON.stringify(batch, null, 2));
-		throw new Error(`Assertion failed: ${label}`);
-	}
-}
-
-function hasEvent(batch, flags, path, field = 'name') {
-	return batch.some(e => (e.mask & flags) === flags && e[field] === path);
-}
-
-try {
-	let op;
-
-	op = await doOp('mkdir /dir_a', () => fs.mkdir(join(mnt, 'dir_a')));
-	assert(op.label, op.batch, b => hasEvent(b, FAN_CREATE | FAN_ONDIR, '/dir_a'));
-
-	op = await doOp('touch /file_a.txt', () => fs.writeFile(join(mnt, 'file_a.txt'), ''));
-	assert(op.label, op.batch, b => hasEvent(b, FAN_CREATE, '/file_a.txt'));
-
-	op = await doOp('write /file_a.txt', () => fs.writeFile(join(mnt, 'file_a.txt'), 'content'));
-	assert(op.label, op.batch, b => hasEvent(b, FAN_CLOSE_WRITE, '/file_a.txt'));
-
-	op = await doOp('mkdir /dir_b', () => fs.mkdir(join(mnt, 'dir_b')));
-	assert(op.label, op.batch, b => hasEvent(b, FAN_CREATE | FAN_ONDIR, '/dir_b'));
-
-	op = await doOp('touch /dir_b/nested.txt', () => fs.writeFile(join(mnt, 'dir_b', 'nested.txt'), ''));
-	assert(op.label, op.batch, b => hasEvent(b, FAN_CREATE, '/dir_b/nested.txt'));
-
-	op = await doOp('mv /file_a.txt /file_b.txt', () => fs.rename(join(mnt, 'file_a.txt'), join(mnt, 'file_b.txt')));
-	assert(op.label, op.batch, b => b.some(e => (e.mask & FAN_RENAME) && e.old === '/file_a.txt' && e.new === '/file_b.txt'));
-
-	op = await doOp('mv /dir_b /dir_a/dir_b_moved', () => fs.rename(join(mnt, 'dir_b'), join(mnt, 'dir_a', 'dir_b_moved')));
-	assert(op.label, op.batch, b => b.some(e => (e.mask & FAN_RENAME) && (e.mask & FAN_ONDIR) && e.old === '/dir_b' && e.new === '/dir_a/dir_b_moved'));
-
-	op = await doOp('chmod 600 /file_b.txt', () => fs.chmod(join(mnt, 'file_b.txt'), 0o600));
-	assert(op.label, op.batch, b => hasEvent(b, FAN_ATTRIB, '/file_b.txt'));
-
-	op = await doOp('touch -m /file_b.txt', () => fs.utimes(join(mnt, 'file_b.txt'), new Date(), new Date()));
-	assert(op.label, op.batch, b => hasEvent(b, FAN_ATTRIB, '/file_b.txt'));
-
-	op = await doOp('chmod 755 /dir_a', () => fs.chmod(join(mnt, 'dir_a'), 0o755));
-	assert(op.label, op.batch, b => hasEvent(b, FAN_ATTRIB | FAN_ONDIR, '/dir_a'));
-
-	op = await doOp('rm /file_b.txt', () => fs.unlink(join(mnt, 'file_b.txt')));
-	assert(op.label, op.batch, b => hasEvent(b, FAN_DELETE, '/file_b.txt'));
-
-	op = await doOp('rm /dir_a/dir_b_moved/nested.txt', () => fs.unlink(join(mnt, 'dir_a', 'dir_b_moved', 'nested.txt')));
-	assert(op.label, op.batch, b => hasEvent(b, FAN_DELETE, '/dir_a/dir_b_moved/nested.txt'));
-
-	op = await doOp('rmdir /dir_a/dir_b_moved', () => fs.rmdir(join(mnt, 'dir_a', 'dir_b_moved')));
-	assert(op.label, op.batch, b => hasEvent(b, FAN_DELETE | FAN_ONDIR, '/dir_a/dir_b_moved'));
-
-	op = await doOp('rmdir /dir_a', () => fs.rmdir(join(mnt, 'dir_a')));
-	assert(op.label, op.batch, b => hasEvent(b, FAN_DELETE | FAN_ONDIR, '/dir_a'));
-
-	console.log('PASS');
-} catch (e) {
-	console.error(e.message);
-	process.exitCode = 1;
-} finally {
-	fa2json.kill();
-	await teardown();
-}