@tuler/kext2

Reproducible ext2 filesystem images from Node.js, without root privileges. This is the native binding of kext2. It stores the same file content as cartesi's xgenext2fs 1.5.6, in valid, byte-for-byte reproducible images with 4 KiB blocks. Its design comes from the Linux kernel's ext2 driver.

import { build, buildBuffer, buildSync, kext2, version } from '@tuler/kext2'

// the command line, in process
const run = await kext2(['--faketime', '--free-space', '64M', '--root', 'rootfs', 'out.ext2'])
console.log(run.stderr) // diagnostics, as the tool prints them

// typed options; builds run on the libuv thread pool
const info = await build('out.ext2', {
  faketime: true,
  freeSpace: 64 << 20, // bytes free on top of the content, and one free inode per 16 KiB
  layers: [
    { type: 'tar', path: 'rootfs.tar.gz' },
    { type: 'dir', path: 'extra', target: '/opt' },
    { type: 'devtable', data: Buffer.from('/dev/console c 600 0 0 5 1 - - -\n') },
  ],
})
console.log(info.blocks, info.freeBlocks, info.freeInodes, info.messages)

// in memory
const image: Buffer = await buildBuffer({ freeSpace: 10 << 20, faketime: true })

The image size is computed from the content plus freeSpace. No blocks are reserved for root, and lost+found always exists.

| option | command line | | |---|---|---| | freeSpace | --free-space | free bytes (default 0), plus one free inode per 16 KiB | | volumeLabel | -L | at most 16 bytes | | faketime, timestamp, clampTimestamps | -f, --timestamp, --clamp-timestamps | mutually exclusive | | sourceDateEpoch | $SOURCE_DATE_EPOCH | filesystem time otherwise | | squashUids, squashPerms | -U, -P | | | layers | -d, -a, -D | { type: 'dir' \| 'tar' \| 'devtable', path \| data, target? }, in order | | threads, verbose | -v | the image does not depend on threads |

Errors reject the promise (or throw, for buildSync) with kext2's message. Writing to standard output ('-') is not supported from Node.js.

Prebuilt binaries: macOS (x64, arm64), Linux glibc ≥ 2.17 (x64, arm64), Windows x64.