![Cosmopolitan Honeybadger](usr/share/img/honeybadger.png) [![build](https://github.com/jart/cosmopolitan/actions/workflows/build.yml/badge.svg)](https://github.com/jart/cosmopolitan/actions/workflows/build.yml) # Cosmopolitan [Cosmopolitan Libc](https://justine.lol/cosmopolitan/index.html) makes C a build-once run-anywhere language, like Java, except it doesn't need an interpreter or virtual machine. Instead, it reconfigures stock GCC and Clang to output a POSIX-approved polyglot format that runs natively on Linux + Mac + Windows + FreeBSD + OpenBSD + NetBSD + BIOS with the best possible performance and the tiniest footprint imaginable. ## Background For an introduction to this project, please read the [αcτµαlly pδrταblε εxεcµταblε](https://justine.lol/ape.html) blog post and [cosmopolitan libc](https://justine.lol/cosmopolitan/index.html) website. We also have [API documentation](https://justine.lol/cosmopolitan/documentation.html). ## Getting Started It's recommended that Cosmopolitan be installed to `/opt/cosmo` and `/opt/cosmos` on your computer. The first has the monorepo. The second contains your non-monorepo artifacts. ``` sudo mkdir -p /opt sudo chmod 1777 /opt git clone https://github.com/jart/cosmopolitan /opt/cosmo (cd /opt/cosmo; make -j8 toolchain) mkdir -p /opt/cosmos/bin export PATH="/opt/cosmos/bin:$PATH" echo 'PATH="/opt/cosmos/bin:$PATH"' >>~/.profile sudo ln -sf /opt/cosmo/tool/scripts/cosmocc /opt/cosmos/bin/cosmocc sudo ln -sf /opt/cosmo/tool/scripts/cosmoc++ /opt/cosmos/bin/cosmoc++ ``` You've now successfully installed your very own cosmos. Now let's build an example program, which demonstrates the crash reporting feature: ```c // hello.c #include #include int main() { ShowCrashReports(); printf("hello world\n"); __builtin_trap(); } ``` To compile the program, you can run the `cosmocc` command. It's important to give it an output path that ends with `.com` so the output format will be Actually Portable Executable. When this happens, a concomitant debug binary is created automatically too. ``` cosmocc -o hello.com hello.c ./hello.com ./hello.com.dbg ``` You can use the `cosmocc` toolchain to build conventional open source projects which use autotools. This strategy normally works: ``` export CC=cosmocc export CXX=cosmoc++ ./configure --prefix=/opt/cosmos make -j make install ``` The Cosmopolitan Libc runtime links some heavyweight troubleshooting features by default, which are very useful for developers and admins. Here's how you can log system calls: ``` ./hello.com --strace ``` Here's how you can get a much more verbose log of function calls: ``` ./hello.com --ftrace ``` If you want to cut out the bloat and instead make your executables as tiny as possible, then the monorepo supports numerous build modes. You can select one of the predefined ones by looking at [build/config.mk](build/config.mk). One of the most popular modes is `MODE=tiny`. It can be used with the `cosmocc` toolchain as follows: ``` cd /opt/cosmo make -j8 MODE=tiny toolchain ``` Now that we have our toolchain, let's write a program that links less surface area than the program above. The executable that this program produces will run on platforms like Linux, Windows, MacOS, etc., even though it's directly using POSIX APIs, which Cosmopolitan polyfills. ```c // hello2.c #include int main() { write(1, "hello world\n", 12); } ``` Now let's compile our tiny actually portable executable, which should be on the order of 20kb in size. ``` export MODE=tiny cosmocc -Os -o hello2.com hello2.c ./hello2.com ``` Let's say you only care about Linux and would rather have simpler tinier binaries, similar to what Musl Libc would produce. In that case, try using the `MODE=tinylinux` build mode, which can produce binaries more on the order of 4kb. ``` export MODE=tinylinux (cd /opt/cosmo; make -j8 toolchain) cosmocc -Os -o hello2.com hello2.c ./hello2.com # <-- actually an ELF executable ``` ## ARM Cosmo supports cross-compiling binaries for machines with ARM microprocessors. There are two options available for doing this. The first option is to embed the [blink virtual machine](https://github.com/jart/blink) by adding the following to the top of your main.c file: ```c STATIC_YOINK("blink_linux_aarch64"); // for raspberry pi STATIC_YOINK("blink_xnu_aarch64"); // is apple silicon ``` The benefit is you'll have single file executables that'll run on both x86_64 and arm64 platforms. The tradeoff is Blink's JIT is slower than running natively, but tends to go fast enough, unless you're doing scientific computing (e.g. running LLMs with `o//third_party/ggml/llama.com`). Therefore, the second option is to cross compile aarch64 executables, by using build modes like the following: ``` make -j8 m=aarch64 o/aarch64/third_party/ggml/llama.com make -j8 m=aarch64-tiny o/aarch64-tiny/third_party/ggml/llama.com ``` That'll produce ELF executables that run natively on two operating systems: Linux Arm64 (e.g. Raspberry Pi) and MacOS Arm64 (i.e. Apple Silicon), thus giving you full performance. The catch is you have to compile these executables on an x86_64-linux machine. The second catch is that MacOS needs a little bit of help understanding the ELF format. To solve that, we provide a tiny APE loader you can use on M1 machines. ``` scp ape/ape-m1.c macintosh: scp o/aarch64/third_party/ggml/llama.com macintosh: ssh macintosh xcode-install cc -o ape ape-m1.c sudo cp ape /usr/local/bin/ape ``` You can run your ELF AARCH64 executable on Apple Silicon as follows: ``` ape ./llama.com ``` ## Source Builds Cosmopolitan can be compiled from source on any Linux distro. First, you need to download or clone the repository. ```sh wget https://justine.lol/cosmopolitan/cosmopolitan.tar.gz tar xf cosmopolitan.tar.gz # see releases page cd cosmopolitan ``` This will build the entire repository and run all the tests: ```sh build/bootstrap/make.com o//examples/hello.com find o -name \*.com | xargs ls -rShal | less ``` If you get an error running make.com then it's probably because you have WINE installed to `binfmt_misc`. You can fix that by installing the the APE loader as an interpreter. It'll improve build performance too! ```sh ape/apeinstall.sh ``` Since the Cosmopolitan repository is very large, you might only want to build a particular thing. Cosmopolitan's build config does a good job at having minimal deterministic builds. For example, if you wanted to build only hello.com then you could do that as follows: ```sh build/bootstrap/make.com o//examples/hello.com ``` Sometimes it's desirable to build a subset of targets, without having to list out each individual one. You can do that by asking make to build a directory name. For example, if you wanted to build only the targets and subtargets of the chibicc package including its tests, you would say: ```sh build/bootstrap/make.com o//third_party/chibicc o//third_party/chibicc/chibicc.com --help ``` Cosmopolitan provides a variety of build modes. For example, if you want really tiny binaries (as small as 12kb in size) then you'd say: ```sh build/bootstrap/make.com m=tiny ``` Here's some other build modes you can try: ```sh build/bootstrap/make.com m=dbg # asan + ubsan + debug build/bootstrap/make.com m=asan # production memory safety build/bootstrap/make.com m=opt # -march=native optimizations build/bootstrap/make.com m=rel # traditional release binaries build/bootstrap/make.com m=optlinux # optimal linux-only performance build/bootstrap/make.com m=fastbuild # build 28% faster w/o debugging build/bootstrap/make.com m=tinylinux # tiniest linux-only 4kb binaries ``` For further details, see [//build/config.mk](build/config.mk). ## Cosmopolitan Amalgamation Another way to use Cosmopolitan is via our amalgamated release, where we've combined everything into a single static archive and a single header file. If you're doing your development work on Linux or BSD then you need just five files to get started. Here's what you do on Linux: ```sh wget https://justine.lol/cosmopolitan/cosmopolitan-amalgamation-2.2.zip unzip cosmopolitan-amalgamation-2.2.zip printf 'main() { printf("hello world\\n"); }\n' >hello.c gcc -g -Os -static -nostdlib -nostdinc -fno-pie -no-pie -mno-red-zone \ -fno-omit-frame-pointer -pg -mnop-mcount -mno-tls-direct-seg-refs -gdwarf-4 \ -o hello.com.dbg hello.c -fuse-ld=bfd -Wl,-T,ape.lds -Wl,--gc-sections \ -include cosmopolitan.h crt.o ape-no-modify-self.o cosmopolitan.a objcopy -S -O binary hello.com.dbg hello.com ``` You now have a portable program. ```sh ./hello.com bash -c './hello.com' # zsh/fish workaround (we patched them in 2021) ``` If `./hello.com` executed on Linux throws an error about not finding an interpreter, it should be fixed by running the following command (although note that it may not survive a system restart): ```sh sudo sh -c "echo ':APE:M::MZqFpD::/bin/sh:' >/proc/sys/fs/binfmt_misc/register" ``` If the same command produces puzzling errors on WSL or WINE when using Redbean 2.x, they may be fixed by disabling binfmt_misc: ```sh sudo sh -c 'echo -1 >/proc/sys/fs/binfmt_misc/status' ``` Since we used the `ape-no-modify-self.o` bootloader (rather than `ape.o`) your executable will not modify itself when it's run. What it'll instead do, is extract a 4kb program (the [APE loader](https://justine.lol/apeloader/)) to `${TMPDIR:-${HOME:-.}}` that maps your program into memory without needing to copy it. The APE loader must be in an executable location (e.g. not stored on a `noexec` mount) for it to run. See below for alternatives: It's possible to install the APE loader systemwide as follows. ```sh # System-Wide APE Install # for Linux, Darwin, and BSDs # 1. Copies APE Loader to /usr/bin/ape # 2. Registers w/ binfmt_misc too if Linux ape/apeinstall.sh # System-Wide APE Uninstall # for Linux, Darwin, and BSDs ape/apeuninstall.sh ``` It's also possible to convert APE binaries into the system-local format by using the `--assimilate` flag. Please note that if binfmt_misc is in play, you'll need to unregister it temporarily before doing this, since the assimilate feature is part of the shell script header. ```sh $ file hello.com hello.com: DOS/MBR boot sector ./hello.com --assimilate $ file hello.com hello.com: ELF 64-bit LSB executable ``` Now that you're up and running with Cosmopolitan Libc and APE, here's some of the most important troubleshooting tools APE offers that you should know, in case you encounter any issues: ```sh ./hello.com --strace # log system calls to stderr ./hello.com --ftrace # log function calls to stderr ``` Do you love tiny binaries? If so, you may not be happy with Cosmo adding heavyweight features like tracing to your binaries by default. In that case, you may want to consider using our build system: ```sh make m=tiny ``` Which will cause programs such as `hello.com` and `life.com` to shrink from 60kb in size to about 16kb. There's also a prebuilt amalgamation online hosted on our download page . ## GDB Here's the recommended `~/.gdbinit` config: ```gdb set host-charset UTF-8 set target-charset UTF-8 set target-wide-charset UTF-8 set osabi none set complaints 0 set confirm off set history save on set history filename ~/.gdb_history define asm layout asm layout reg end define src layout src layout reg end src ``` You normally run the `.com.dbg` file under gdb. If you need to debug the `.com` file itself, then you can load the debug symbols independently as ``` gdb foo.com -ex 'add-symbol-file foo.com.dbg 0x401000' ``` ## Alternative Development Environments ### MacOS If you're developing on MacOS you can install the GNU compiler collection for x86_64-elf via homebrew: ```sh brew install x86_64-elf-gcc ``` Then in the above scripts just replace `gcc` and `objcopy` with `x86_64-elf-gcc` and `x86_64-elf-objcopy` to compile your APE binary. ### Windows If you're developing on Windows then you need to download an x86_64-pc-linux-gnu toolchain beforehand. See the [Compiling on Windows](https://justine.lol/cosmopolitan/windows-compiling.html) tutorial. It's needed because the ELF object format is what makes universal binaries possible. Cosmopolitan officially only builds on Linux. However, one highly experimental (and currently broken) thing you could try, is building the entire cosmo repository from source using the cross9 toolchain. ``` mkdir -p o/third_party rm -rf o/third_party/gcc wget https://justine.lol/linux-compiler-on-windows/cross9.zip unzip cross9.zip mv cross9 o/third_party/gcc build/bootstrap/make.com ``` ## Discord Chatroom The Cosmopolitan development team collaborates on the Redbean Discord server. You're welcome to join us! ## Support Vector | Platform | Min Version | Circa | | :--- | ---: | ---: | | AMD | K8 Venus | 2005 | | Intel | Core | 2006 | | Linux | 2.6.18 | 2007 | | Windows | 8 [1] | 2012 | | Mac OS X | 15.6 | 2018 | | OpenBSD | 6.4 | 2018 | | FreeBSD | 13 | 2020 | | NetBSD | 9.2 | 2021 | [1] See our [vista branch](https://github.com/jart/cosmopolitan/tree/vista) for a community supported version of Cosmopolitan that works on Windows Vista and Windows 7. ## Special Thanks Funding for this project is crowdsourced using [GitHub Sponsors](https://github.com/sponsors/jart) and [Patreon](https://www.patreon.com/jart). Your support is what makes this project possible. Thank you! We'd also like to give special thanks to the following groups and individuals: - [Joe Drumgoole](https://github.com/jdrumgoole) - [Rob Figueiredo](https://github.com/robfig) - [Wasmer](https://wasmer.io/) For publicly sponsoring our work at the highest tier.