stargazing/README.md

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# stargazing
this repository contains experiments
in building third-party software against
[cosmopolitan libc.](https://justine.lol/cosmopolitan/)
the provided scripts produce APEs
(Actually Portable Executables) that run on
Linux, Mac, Windows, FreeBSD, OpenBSD, and NetBSD.
**however,** despite *running* on all platforms,
not every feature is available on every platform.
cosmopolitan already does a tremendous job at
polyfilling missing features across platforms,
but pre-existing software still takes a lot of
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patching before becoming fully functional.
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## building
on most Linux distros with podman properly installed and configured,
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it should suffice to run [`./build-all`][ba] in the root of the repository.
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binaries are copied to the `out/` directory upon success.
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[ba]: https://eaguru.guru/git/notwa/stargazing/src/branch/galaxy/build-all
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## installing
no installation is necessary — everything in the `out/` directory is self-contained.
however, if you'd like to use create
your own pseudo-release of cosmopolitan to build against,
you can run `install-cosmo` to install an amalgamation to `/opt/cosmopolitan/`.
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this includes the amalgamation (in `dist/`),
the gcc toolchain (in `gcc/`),
some essential APEs (in `bin/`),
and all the necessary headers.
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## notes
### Docker
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this project uses [Dockerfiles][df] to allow for *mostly-reproducible* builds.
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[podman is used][podman] instead of docker, because the official docker software
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is commercial and obnoxious.
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**neither docker nor podman is required for executing the binaries.**
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binaries are to be isolated and extracted from the resulting containers.
those binaries can then be transferred across platforms, like any other APE.
[df]: https://docs.docker.com/engine/reference/builder/
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[podman]: https://docs.podman.io/en/latest/markdown/podman-build.1.html
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in the future, it would be nice to use something
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like [what Void Linux does for its packages,][void]
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which would entirely sidestep the clunkiness
of Dockerfiles and working with containers.
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[void]: https://github.com/void-linux/void-packages
make no mistake, this project does *not* strive for reproducible builds
[in any way that nix does.](https://nixos.org/guides/how-nix-works.html)
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### Host OS
this project must be built on a host running Linux.
if you are not running Linux, use a VM of some sort.
i personally use VirtualBox running Alpine Linux.
i have not tried building with WSL2.
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### Code Style
this project encourages a heretical and horrifying style of code
for its shell scripts. the intent is to chain `&&`s while facilitating
trivial re-ordering of lines. for instance, a `RUN` command in a Dockerfile
(which just executes a line of shell) might look like this:
```sh
RUN : \
&& echo hello \
&& note() \
{ : \
&& printf '\033[1m%s\033[m: %s\n' >&2 \
noted "$*" \
;} \
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# this is an inline comment! it should end with a semicolon, \
# because vim's syntax highlighting is bad. \
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&& note '\\( o _ o )//' \
;
```
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a good example of a script in this style is
[the `acquire` script.](https://eaguru.guru/git/notwa/stargazing/src/branch/galaxy/notwa-util/acquire)
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#### gratuitous explanation
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* 4-space indentation is a must, since at least three characters
are needed to contain the operators on the left of each line.
* `:` is akin to the `true` command; it's used as a no-op
that only sets the most recent exit code (`$?`) to `0`.
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* `\` continues the shell command to the next line;
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the proceeding newline is removed and ignored.
* `&&` is a short-circuiting operator that only evaluates
its right-hand side when `$?` is `0`. `&&` is preferred
over a simple semicolon because most programs use a
non-zero exit code to indicate that an error occurred,
whereas `;` will continue executing code,
even in the presence of an error.
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**note:** the `diff` command breaks the convention
and uses both `0` and `1` as normal exit codes.
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* `||` is like `&&` but only executes when `$?` is *not* `0`.
**important:** `||` has a lower precedence than `&&`!
make sure to wrap your `||`s in braces unless you want to
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capture *everything* before it. for example, an excerpt
of a shell script might look like this:
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` && { test -e myfile || touch myfile ;} \`
* leftmost `&&`s and `||`s are always centered within their 4-space indent.
* avoid using pipes (`|`) when possible, because only the
exit code of the final command in any pipe is respected.
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instead, write intermediate data to `/tmp` when possible.
remember to mount `/tmp` as a `tmpfs` at the start of the `RUN` command!
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* functions are declared (`()`) on their own line
without any braces or other commands.
* `{ :` is used to begin a multi-line block,
similar to how `RUN :` begins a shell command.
sadly, the space between the brace and the colon is not optional.
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* `;}` is used to finish a multi-line block.
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this is aligned with the preceeding `&&` and `||` operators.
thankfully, the space between `;` and `}` is optional.
* a final `;` is used to finish off the line-continutation.
this means that every line before it can end with a `\`,
which simplifies editing. when podman gives you strange errors,
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double-check that you aren't forgetting a `\` or the final semicolon.
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* redirections are usually specified *before* a final list of arguments.
this makes skimming code easier when arguments extend across many lines.
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* **TODO:** explain `if cmd \␤ ;then : \␤ && cmd \␤ ;fi`.
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* **TODO:** explain `for cmd \␤ ;do : \␤ && cmd \␤ ;done`.
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* **TODO:** explain `while cmd \␤ ;do : \␤ && cmd \␤ ;done`.
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* **TODO:** explain `test`s?
* **TODO:** explain the two different kinds of commends.