A modern C++23 BusyBox alternative — single binary, 123 applets, 399 tests. Runs as PID 1 on the i.MX6ULL, replacing BusyBox.
Above: cfbox booting the imx-forge rootfs as PID 1 — runs
rcS(mount/mdev), printsPlease press Enter to activate this console.(askfirst), and drops into a cfboxshafter Enter.
CFBox is a single-executable Unix utility collection distributed via symbolic links. 123 applets are implemented and tested, with a CI pipeline covering native builds, cross-compilation (armhf/aarch64), and QEMU user/system-mode testing. It supports configurable CMake builds (per-applet toggles), GNU-style long options, and colored help output. The long-term goal is to gradually catch up to — and even surpass — mainstream coreutils.
Design philosophy: Simplicity first — Modern C++ (std::expected, no exceptions / no RTTI) — Embedded-friendly (cross-compilation, static linking, runs as PID 1 init).
cfbox replaces BusyBox on the NXP i.MX6ULL (armhf, Cortex-A7), serving as PID 1 + the toolset for the imx-forge rootfs and driving the full boot loop:
| Boot stage | Handled by cfbox |
|---|---|
| PID 1 | init — parses BusyBox-format /etc/inittab; supports sysinit/askfirst/respawn/ctrlaltdel/shutdown |
| rcS | mount -a / mount -t devpts devpts /dev/pts / mdev -s (coldplug: scan /sys to populate /dev) |
| console | askfirst → Please press Enter to activate this console. → Enter → cfbox sh |
| Shutdown | umount -a -r / swapoff -a / reboot |
Verified live: /proc/cpuinfo reports ARMv7 Processor rev 5 (v7l) (i.MX6ULL); cfbox sh is interactive, and ls/cat/df/ps/uname/free dispatch normally.
armhf static build (self-contained, run directly as PID 1):
cmake -B build-armhf-static \ -DCMAKE_TOOLCHAIN_FILE=cmake/toolchain/Toolchain-armhf.cmake \ -DCMAKE_BUILD_TYPE=Release \ -DCFBOX_OPTIMIZE_FOR_SIZE=ON \ -DCFBOX_STATIC_LINK=ON cmake --build build-armhf-static -j$(nproc) # ~1.2 MB output
The table below is auto-generated by the in-repo scripts/gen_size_table.sh.
| Project | Language | Size | Applets | Size/Applet |
|---|---|---|---|---|
| CFBox (size-opt) | C++23 | 418 KB | 123 | ~3.4 KB |
| CFBox (armhf static) | C++23 | ~1.2 MB | 123 | — |
| Toybox | C | ~500 KB | 238 | ~2.1 KB |
| BusyBox (full) | C | ~1.7 MB | 274 | ~9 KB |
| uutils/coreutils | Rust | ~11 MB | ~100 | ~110 KB |
CFBox is 3-4x smaller than BusyBox while shipping a complete AWK interpreter, an archive suite (tar/cpio/ar/unzip/gzip), diff/patch (Myers O(ND) algorithm), a process toolkit (ps/top/pstree/pgrep/pmap), and a built-in TUI framework.
We are still working to approach the performance of mainstream box tools (BusyBox/Toybox) using C++.
| Operation | Data Size | Time |
|---|---|---|
| grep -c | 10 MB | 54 ms |
| cat | 10 MB | 63 ms |
| wc | 10 MB | 17 ms |
| sort | 100K lines | 32 ms |
| diff | 100K lines (similar) | 79 ms |
- grep/cat/wc use streaming I/O — reading
/dev/urandomwon't exhaust memory - diff uses the Myers O(ND) algorithm; sort precomputes keys to avoid repeated allocation
- Zero external dependencies: a hand-written lightweight deflate/inflate replaces zlib
# Build
cmake -B build
cmake --build build
# Test
ctest --test-dir build --output-on-failure # 399 GTest unit tests
bash tests/integration/run_all.sh # 54 integration test scripts
# Run via subcommand
./build/cfbox echo "Hello, World!"
# Or install symbolic links
./scripts/gen_links.sh /usr/local/bin
echo "Hello, World!" # now calls cfbox via symlinkecho, printf, cat, head, tail, wc, sort, uniq, grep, sed, fold, expand, cut, paste, nl, comm, tr, tac, rev, shuf, factor, od, split, seq, tsort, expr, awk, diff, patch, cmp, ed
mkdir, rm, cp, mv, ls, find, ln, touch, stat, install, mktemp, truncate, du, df, readlink, realpath, rmdir, link, unlink, chmod, chown, chgrp
tar (ustar format), cpio (newc format), ar (static library), unzip, gzip, gunzip
sh (POSIX shell: pipes, redirections, variable expansion, command substitution, if/while/for, 15 builtins), xargs
pwd, basename, dirname, uname, hostname, whoami, id, tty, date, nproc, logname, hostid, printenv, env, uptime, free, cal, dmesg, who, test, [
ps, top, kill, pgrep/pkill, pidof, pstree, pmap, fuser, pwdx, sysctl, iostat, watch, nice, renice, timeout
mount (-a/-t/-o, reads fstab), umount (-a/-r/-f), mdev (-s coldplug), mountpoint, init (PID 1, parses inittab + askfirst), reboot, poweroff, swapoff, sync, mkfifo, mknod, clear
true, false, yes, sleep, usleep, nohup, cksum, md5sum, sum, hexdump, more, tee, which
All applets support
--help/--version
- Compiler: GCC 13+ / Clang 17+ (C++23 support required)
- CMake: 3.26+
- Platform: Linux (x86_64 / aarch64 / armhf; supports static linking as PID 1 init)
| Document | Description |
|---|---|
| Architecture & Design | Dispatch mechanism, core infrastructure, error handling, testing |
| Production Roadmap | Production roadmap docs for Phase 4.5 to v1.0; currently maintained in Chinese |
| Cross-Compilation & Embedded | Toolchains, CMake options, build examples, binary sizes |
| QEMU Testing | User-mode / system-mode testing, init applet, kernel config |
| Continuous Integration | CI pipeline overview |
| Contributing Guide | Build, test, code style, submission |
cfbox/
├── CMakeLists.txt
├── cmake/
│ ├── Config.cmake # Per-applet configuration (CFBOX_ENABLE_xxx options)
│ ├── compile/CompilerFlag.cmake # Compiler warnings & optimization flags
│ ├── third_party/CPM.cmake # CPM dependency manager (GTest only)
│ └── toolchain/ # Cross-compilation toolchains
├── include/cfbox/
│ ├── applet.hpp / applets.hpp # Registry & dispatch
│ ├── args.hpp # Short + long option argument parser
│ ├── error.hpp # std::expected error handling + CFBOX_TRY
│ ├── io.hpp # Streaming I/O (for_each_line, read_all, write_all)
│ ├── stream.hpp # Line-by-line pipeline, LineProcessor
│ ├── deflate.hpp / inflate.hpp # Hand-written lightweight DEFLATE (zero deps)
│ ├── compress.hpp # gzip wrapper
│ ├── utf8.hpp # Unicode width/count (constexpr + static_assert)
│ ├── term.hpp # ANSI colored output (NO_COLOR support)
│ ├── terminal.hpp # Terminal control (RawMode RAII, cursor, double buffer)
│ ├── tui.hpp # TUI framework (ScreenBuffer, Key, TuiApp)
│ ├── proc.hpp # /proc parser (processes, memory, CPU, disks)
│ ├── regex.hpp # POSIX regex RAII (scoped_regex)
│ └── ... # help.hpp, fs_util.hpp, escape.hpp, checksum.hpp
├── src/
│ ├── main.cpp # Dispatch entry
│ └── applets/ # 123 command implementations
├── tests/
│ ├── unit/ # GTest unit tests (399 cases)
│ └── integration/ # Shell integration tests (54 scripts)
└── scripts/ # Build, test, install scripts
Current release: v0.3.0 (Phase 1.5 code quality review + L2 rootfs boot skeleton complete; cfbox now runs on the i.MX6ULL). Focus returns to Phase 2: core command deepening.
Closed every gap needed for cfbox to replace BusyBox as PID 1: init (askfirst), mount, mdev, umount, swapoff, reboot/poweroff — verified booting to console on the i.MX6ULL with the imx-forge rootfs.
Deepening existing commands from ~30% to ~70% feature completeness, in batches by operational frequency:
| Batch | Commands | Key Additions |
|---|---|---|
| Batch 1 | tail, cp, test, ls |
tail -f ✅, cp -a, full POSIX test, ls -R/--color |
| Batch 2 | grep, tar, sed, sort |
grep -A/-B/-C, tar -z/-v, sed -i, sort -k |
| Batch 3 | find, sh, ps, df, du |
find boolean expressions, sh case/heredoc/functions |
See document/todo/README.md for the full roadmap.
See CONTRIBUTING.md.
MIT License — see LICENSE for details.