radare2/dist/reactos

radare2 on ReactOS, in the browser

Builds a small ReactOS disk image with the radare2 w32 (mingw32) build preinstalled in C:\radare2, plus a static website that boots that image inside the browser so people can test w32 builds of radare2 without installing anything — phones included.

The browser side uses v86, a wasm x86 PC emulator with full VGA output, mouse/keyboard and low memory requirements. (qemu's wasm port was considered but it only provides a serial console — no graphics — and needs ~2.3GB of browser memory, which excludes phones.) The disk image is streamed on demand with HTTP Range requests: visitors only download the sectors ReactOS actually reads (a few tens of MB for a boot), not the whole disk.

Dependencies

sudo apt install curl unzip xorriso qemu-system-x86 qemu-utils mtools
# plus mingw to build radare2 for w32: gcc-mingw-w64-i686

Run make check-tools to verify.

Build

make            # everything: reactos.qcow2 + www/
make image      # only the qcow2
make www        # only the website
make serve      # test locally on http://localhost:8080
make run        # boot reactos.qcow2 in native qemu

What happens under the hood:

1. Downloads the ReactOS BootCD, enables UnattendSetupEnabled in its unattend.inf (reinjected with xorriso, keeping the iso bootable).
2. Runs the unattended install headless in qemu: two -no-reboot runs, one per setup stage (text mode, then gui). With KVM this takes minutes.
3. Unzips a radare2-*-mingw32.zip (built with make w32 in the repo root if none exists — pass R2_W32_ZIP=/path/to.zip to use your own) and copies it into C:\radare2 on the FAT partition with mtools, plus an r2.cmd wrapper in system32 so r2 works from any cmd prompt.
4. Produces reactos.qcow2 (compressed) and www/images/reactos.img (raw, sparse) plus the v86 emulator files and the html page.

Useful knobs: DISK_MB=2048 (disk size), WEB_MEM_MB=256 (guest RAM in the browser), QEMU_DISPLAY= (watch the unattended install instead of running it headless), REACTOS_VER/REACTOS_ZIP_URL (other releases).

Hosting www/

Copy the www/ directory to any static host. Requirements:

• Range requests: the host must honor Range: headers on images/reactos.img (nginx, apache, caddy, most CDNs do; python's builtin http.server does not — use the bundled serve.py).
• Sparse transfer: reactos.img is mostly holes; upload with rsync -S or pack with tar -Szcf to avoid transferring zeros.
• config.js and sw.js should be served with Cache-Control: no-cache (everything else can be cached aggressively; asset urls carry a ?v=<image-hash> so new builds invalidate naturally).

Caching

A service worker caches the emulator, bios and page after the first visit, and the browser's http cache keeps the disk chunks. The page has a Clear cache button that deletes the CacheStorage, unregisters the service worker, bumps the cache-busting query and reloads — use it when a new image is uploaded but the browser insists on the old one (stale cache entries from previous builds are also pruned automatically at boot).

Using it

The page boots straight to the ReactOS desktop (no password). Open cmd from the Start menu and run e.g.:

r2 C:\ReactOS\system32\cmd.exe

On phones: drag on the screen to move the mouse pointer, tap to click, long-press to right-click, and use the Keyboard button to open the soft keyboard.

Use Upload files, or drag files onto the page, to create and mount a temporary transfer CD in ReactOS (normally D:). The image is generated entirely in the browser; files are not sent to the web server. Uploading again replaces the CD, and Eject files removes it. For browser-memory safety a single transfer is limited to 128 MB. ISO-compatible filenames are used, so unsupported characters and long names may be shortened in the guest.