Add README (#15)

Add a `README.md` to this project. It's needed for the final submission.

Commits:
* Added README
* Modified Makefile to use the distribution build

Makefile.toml

@@ -77,7 +77,7 @@ run_task = "sus-release-build"
 [tasks.install]
 description = "Install the application"
 category = "Install"
-dependencies = [ "sus-release-build" ]
+dependencies = [ "sus-dist-build" ]
 env_files = [
  { path = "./config/install.env" }
 ]

README.md

@@ -0,0 +1,82 @@
+# `sudo` in UserSpace
+
+This project was created for the Fall 2021 Semester of CS 3210 at Georgia Tech.
+It is a re-implementation of `sudo` that experiments with moving as much
+computation off the `root` user as possible. That is, it aims to have most of
+the code in unprivileged binaries, with those programs only `exec`ing to
+escalate privilege when absolutely necessary.
+
+See also the
+* [Proposal](https://docs.google.com/document/d/17gTYkPF2tVHxffUQAEohYeq5u5XpvCrTnsoOFiNkf6c/edit?usp=sharing)
+* [Final Report](https://docs.google.com/document/d/1k9ENTLjWKn68N2SxBkzi5DJK2EWbTG-0JbeMDbRMtxE/edit?usp=sharing)
+
+
+## Obtaining a Copy
+
+### Downloading from Releases
+
+The binaries and documentation for this project can be obtained from the
+[Releases](https://github.com/ammrat13/sus/releases) section. The versions
+present there were compiled with all features enabled. If this is undesireable,
+it is possible to compile the binary manually.
+
+### Compiling
+
+#### Build Environment
+
+This project has a [Docker container](https://hub.docker.com/repository/docker/ammrat13/sus)
+with the environment necesary to build this project. Simply clone this
+repository and mount it as a volume at `/usr/local/src/sus/` - the initial
+working directory.
+
+Alternatively, it is possible to set up the environment manually. Like most Rust
+projects, `sus` uses `cargo` as a build system. The container comes with version
+`1.56.0`. It also uses the `rustfmt` and `clippy` components for formatting and
+linting respectively, as well as `cargo-audit` version `0.15.2` to check for
+known vulnerable dependencies. To automate the build process, `sus` also uses
+`cargo-make` version `0.35.5`.
+
+#### Build Process
+
+Once the environment is set up, `sus` can be built with
+```
+$ cargo make sus-dist-build
+```
+This will compile the project with the default features, unlike the Releases
+page which compiles with all features.
+
+At the moment, it's necessary to edit the `Makefile.toml` to select which
+features to build. Under `[tasks.sus-dist-build]`, edit
+```
+env = { "CARGO_MAKE_CARGO_BUILD_TEST_FLAGS" = "" }
+```
+to instead contain the arguments to be passed to `cargo-build`.
+
+#### Installation Process
+
+The `Makefile.toml` has an `install` target. It automatically builds the
+application and installs it to the configured location. This can be invoked with
+```
+$ cargo make install
+```
+
+Alternatively, it is possible to manually install the project by copying over
+the binaries from the `target/release/` directory and changing their
+permissions.
+
+### Configuring
+
+A default configuration is given in the `config/` folder, and the builds on the
+Releases page use it. However, the parameters in those files can be edited.
+
+
+## Running
+
+As this program is written in Rust, the binaries can be run like any other
+program once they are compiled.
+
+The arguments to the `sus-kernel` binary are defined in `config/sus-kernel.rs`
+by all the parameters ending in `_IDX`. However, ideally the kernel should not
+be run directly. Instead, a wrapper program should be used to parse user
+arguments and massage them into the "computer-friendly" format used by the
+kernel. Sadly, no such program exists at the moment.