Chapter 4. Slow Porting
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## Chapter 4. Slow Porting

Ok, so it was not that simple, and the port required some modifications to get it to work. In this section, we will explain, step by step, how to modify it to get it to work with the ports paradigm.

## 4.1. How Things Work

First, this is the sequence of events which occurs when the user first types `make` in your port's directory. You may find that having `bsd.port.mk` in another window while you read this really helps to understand it.

But do not worry if you do not really understand what `bsd.port.mk` is doing, not many people do... :-)

1. The `fetch` target is run. The `fetch` target is responsible for making sure that the tarball exists locally in `DISTDIR`. If `fetch` cannot find the required files in `DISTDIR` it will look up the URL `MASTER_SITES`, which is set in the Makefile, as well as our main FTP site at ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/distfiles/, where we put sanctioned distfiles as backup. It will then attempt to fetch the named distribution file with `FETCH`, assuming that the requesting site has direct access to the Internet. If that succeeds, it will save the file in `DISTDIR` for future use and proceed.

2. The `extract` target is run. It looks for your port's distribution file (typically a `gzip`ped tarball) in `DISTDIR` and unpacks it into a temporary subdirectory specified by `WRKDIR` (defaults to `work`).

3. The `patch` target is run. First, any patches defined in `PATCHFILES` are applied. Second, if any patch files named `patch-`*`` are found in `PATCHDIR` (defaults to the `files` subdirectory), they are applied at this time in alphabetical order.

4. The `configure` target is run. This can do any one of many different things.

   1. If it exists, `scripts/configure` is run.

   2. If `HAS_CONFIGURE` or `GNU_CONFIGURE` is set, ``WRKSRC`/configure` is run.

5. The `build` target is run. This is responsible for descending into the port's private working directory (`WRKSRC`) and building it. If `USES= gmake` is set, GNU `make` will be used, otherwise the system `make` will be used.

The above are the default actions. In addition, you can define targets `pre-`something`` or `post-`something``, or put scripts with those names, in the `scripts` subdirectory, and they will be run before or after the default actions are done.

For example, if you have a `post-extract` target defined in your `Makefile`, and a file `pre-build` in the `scripts` subdirectory, the `post-extract` target will be called after the regular extraction actions, and the `pre-build` script will be executed before the default build rules are done. It is recommended that you use `Makefile` targets if the actions are simple enough, because it will be easier for someone to figure out what kind of non-default action the port requires.

The default actions are done by the `bsd.port.mk` targets `do-`something``. For example, the commands to extract a port are in the target `do-extract`. If you are not happy with the default target, you can fix it by redefining the `do-`something`` target in your `Makefile`.

### Note:

The “main” targets (e.g., `extract`, `configure`, etc.) do nothing more than make sure all the stages up to that one are completed and call the real targets or scripts, and they are not intended to be changed. If you want to fix the extraction, fix `do-extract`, but never ever change the way `extract` operates! Additionally, the target `post-deinstall` is invalid and is not run by the ports infrastructure.

Now that you understand what goes on when the user types `make`, let us go through the recommended steps to create the perfect port.

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3.6. Submitting the New Port | Home | 4.2. Getting the Original Sources

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