Building userspace applications

This page outlines the steps and tools required to build and install laritOS applications.

Toolchain build script

laritos-toolchain comes with a python build script designed to ease the process of building applications. You can list all the options with:

$ $LARITOSTOOL/build/build.py -h

usage: build.py [-h] [-i path | -c] [--arch ARCH] [--subarch SUBARCH] [-p] [--crossc CROSSC] [-v] app [app ...]

laritOS application builder

positional arguments:
  app                   Path to the application to build

optional arguments:
  -h, --help            show this help message and exit
  -i path, --install path
                        Install object files in the given system image root
                        path (default: None)
  -c, --clean           Remove all objects rather than building the app/s
                        (default: False)
  --arch ARCH           Target architecture (default: arm)
  --subarch SUBARCH     Target sub-architecture (if any) (default: armv7-a)
  -p, --printdatabase   Print the data base (rules and variable values) that
                        results from reading the makefiles (default: False)
  --crossc CROSSC       Cross compiler (default: arm-none-eabi-)
  -v, --verbose         Increase logging (default: False)

Building applications

As you can see from the build.py -h command output, in order to build an app you need to indicate the path to the application. For example, to build the shell:

 $LARITOSTOOL/build/build.py $LARITOSAPPS/shell

This will generate an ELF (Executable and Linkable Format) binary under the $LARITOSAPPS/shell/<architecture>/bin folder.

Installing applications

If you want to have the application available in the OS, you need to install it in either the system or data image. To do that, build.py provides the -i option to install the app binary and all its resources under the given directory.

For example, to build and install the shell in the OS system image:

$LARITOSTOOL/build/build.py $LARITOSAPPS/shell -i $LARITOS/bin/image/system

You'll see in the output all the binaries and resources being copied into the system image folder:

Building 'shell'
make: Entering directory '/home/lzungri/dev/src/laritos-apps/shell'
CC      bin/arm//home/lzungri/dev/src/laritos-toolchain/arch/generic/src/heap.o
CC      bin/arm//home/lzungri/dev/src/laritos-toolchain/arch/generic/src/stack.o
CC      bin/arm//home/lzungri/dev/src/laritos-toolchain/arch/generic/src/printf.o
CC      bin/arm//home/lzungri/dev/src/laritos-toolchain/arch/generic/src/string.o
CC      bin/arm//home/lzungri/dev/src/laritos-toolchain/arch/generic/src/stdio.o
CC      bin/arm/main.o
CC      bin/arm/builtins.o
AS      bin/arm//home/lzungri/dev/src/laritos-toolchain/arch/arm/src/start.o
LD      bin/arm/shell.elf
CP      banners/1 -> /home/lzungri/dev/src/laritos/bin/image/system/res/shell/banners/1
CP      banners/2 -> /home/lzungri/dev/src/laritos/bin/image/system/res/shell/banners/2
CP      banners/3 -> /home/lzungri/dev/src/laritos/bin/image/system/res/shell/banners/3
CP      banners/4 -> /home/lzungri/dev/src/laritos/bin/image/system/res/shell/banners/4
CP      banners/5 -> /home/lzungri/dev/src/laritos/bin/image/system/res/shell/banners/5
CP      banners/6 -> /home/lzungri/dev/src/laritos/bin/image/system/res/shell/banners/6
CP      banners/7 -> /home/lzungri/dev/src/laritos/bin/image/system/res/shell/banners/7
CP      banners/8 -> /home/lzungri/dev/src/laritos/bin/image/system/res/shell/banners/8
CP      banners/9 -> /home/lzungri/dev/src/laritos/bin/image/system/res/shell/banners/9
CP      bin/arm/shell.elf -> /home/lzungri/dev/src/laritos/bin/image/system/bin
make: Leaving directory '/home/lzungri/dev/src/laritos-apps/shell'

Once you copy the binary+resources you'll need to regenerate the OS system image with:

cd $LARITOS
CROSS_COMPILE=arm-none-eabi- make system.img

or just rebuild the whole OS with:

cd $LARITOS
CROSS_COMPILE=arm-none-eabi- make

If you don't rebuild, the binary will still be located under the system image folder [*] but not packaged into the system.img file, which is the actual filesystem mounted by the OS.

[*] The folder is just a temporary storage for generating the system.img

Misc commands

Building and installing all apps

$LARITOSTOOL/build/build.py * -i $LARITOS/bin/image/system

Clean all apps

$LARITOSTOOL/build/build.py -c *

Build shell and print make commands (for debugging)

$LARITOSTOOL/build/build.py -v shell