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1. Basics

/patches/ports/port.sh is a script that helps building libraries and software for the system more easily.

To install one of the ports in the local port directory, use:

sh port.sh libpng/1.6.18

This will automatically download the source archive from the Ghost repository (https://ghostkernel.org/repository/), apply the available patches and build the library into the sysroot.

2. Port structure

The script only builds a small framework that allows it to be more flexible for a variety of builds.

A port resides in a folder with the name of the library or application, then a folder with its version. Each port must have a package.sh file and may optionally have a patch.diff.

libpng/
	1.6.18/
		package.sh
		patch.diff

3. Creating a port

The package.sh is the "description" for the port. It is first used to determine where the source archive for the port shall be downloaded from, what the archives file name is and where to unpack it. The second thing that it defines must be the two functions port_unpack and port_install. The following is an example taken from the libpng port:

REMOTE_ARCHIVE="https://ghostkernel.org/repository/libpng/libpng-1.6.18.tar.gz"
UNPACKED_DIR=libpng-1.6.18
ARCHIVE=libpng-1.6.18.tar.gz

port_unpack() {
	tar -xf $ARCHIVE
}

port_install() {
	../$UNPACKED_DIR/configure --host=$TARGET --prefix=$PREFIX
	make
	make DESTDIR=$SYSROOT install
}

When this port is installed, the script will perform a series of steps to install the port.

  1. Create an empty output directory within the build folder

  2. Download the archive file into that directory

  3. Call port_unpack to unpack the archive

  4. Apply the patch.diff if supplied

  5. Call port_install to perform the installation

The variable $SYSROOT is given in the context of port_install and shall be used to install the port to the system root.