5. Writing First Recipe

Goal of this lesson is to write a recipe that will inject bash scripts and text files into the system image.

You will need to utilize the IMAGE_INSTALL variable discussed in previous sections to get content placed into system image. Normally one should avoid updating local.conf, but for this tutorial adding it there is fine.

You also need to seperate the installed files into two seperate packages.

scripts & text

5.1. Creating recipe

$ mkdir -p recipes-mydistro/injectme/{scripts,texts}
$ touch recipes-mydistro/injectme/injectme_0.0.1.bb

5.2. Recipe Core Structure

Remember to revist the Yocto Project Variable Glossary if you don’t know what a given variable is used for.

An important variable to the do_install task is ${D} (Destination). It’s usually set to a given recipes ${WORKDIR}/image before being packaged.

Any files placed in ${D} will go onto the system image in that exact directory. It’ll also find it’s way into another recipes sysroot (${WORKDIR}/recipe-sysroot) or native sysroot (${WORKDIR}/recipe-sysroot-native) via the DEPENDS variable.

SUMMARY = "Inject files into Yocto built linux system image."
HOMEPAGE = "here"

# Doesn't matter
SECTION = "examples"

LICENSE = "MIT"
LIC_FILES_CHKSUM = "file://${COMMON_LICENSE_DIR}/MIT;md5=0835ade698e0bcf8506ecda2f7b4f302"

DEPENDS = ""
RDEPENDS:${PN} = "bash"

# := Means expand variable immediately
FILESEXTRAPATHS:prepend := "${THISDIR}/scripts:"
FILESEXTRAPATHS:prepend := "${THISDIR}/texts:"

SRC_URI = ""

S = "${WORKDIR}"

do_install() {

}

# List of packages a recipe can produce
PACKAGES += ""
PROVIDES += ""
RPOVIDES:${PN} += ""

FILES:${PN} += ""

5.3. Files To Inject

set-bash-prompt.sh place in /etc/profile.d -> ${sysconfdir}/profile.d

set_bash_prompt() {
        fs_mode=$(mount | sed -n -e "s/^\/dev\/.* on \/ .*(\(r[w|o]\).*/\1/p")
        PS1='\[\e[91;1m\]\u@\h ${fs_mode:+($fs_mode)}\[\033[00m\]: \[\e[33;1m\]\W \[\e[32;1m\]\$ \[\033[0m\]'
}

PROMPT_COMMAND=set_bash_prompt

extra-alias.sh place in /etc/profile.d -> ${sysconfdir}/profile.d

NORMAL=`echo -e '\x1b[0m'`
RED=`echo -e '\x1B[31;1m'`
LGREEN=`echo -e '\033[1;32m'`
IBLUE=`echo -e '\x1B[30;1m'`
LBLUE=`echo -e '\033[1;34m'`
YELLOW=`echo -e '\x1B[33;1m'`
MAGENTA=`echo -e '\e[37;1m'`
IP_CMD=$(which ifconfig)

colored_ip() {
        ${IP_CMD} $@ | sed \
                -e "s/inet [^ ]\+ /${LGREEN}&${NORMAL}/g"\
                -e "s/ether [^ ]\+ /${RED}&${NORMAL}/g"\
                -e "s/netmask [^ ]\+ /${LBLUE}&${NORMAL}/g"\
                -e "s/broadcast [^ ]\+ /${IBLUE}&${NORMAL}/g"\
                -e "s/^default via .*$/${YELLOW}&${NORMAL}/g"\
                -e "s/^\([0-9]\+: \+\)\([^ \t]\+\)/\1${MAGENTA}\2${NORMAL}/g"
}

alias ifconfig='colored_ip'

alias vi='vim'

alias ls='ls --color'
alias dir='dir --color=auto'
alias vdir='vdir --color=auto'

alias grep='grep --color=auto'
alias fgrep='fgrep --color=auto'
alias egrep='egrep --color=auto'

# some more ls aliases
alias ll='ls -alF'
alias la='ls -A'
alias l='ls -CF'

testing.txt

Injecting Cool text file bro

5.4. Recipe Execution

5.4.1. Build Recipe

After running bellow bitbake will execute all task defined in the injectme recipe.

MACHINE="qemux86-64" DISTRO="mydistro" bitbake injectme

5.4.2. Run Recipe Task

To run an individual task/function

MACHINE="qemux86-64" DISTRO="mydistro" bitbake injectme -c install

5.4.3. Devshell

The devshell is useful as it give a working environment to test in prior to finishing a recipe. Very useful when debugging stick cross-compile situations.

MACHINE="qemux86-64" DISTRO="mydistro" bitbake injectme -c devshell

# Most task can be executed by running the scripts in temp
./temp/run.do_install

5.5. Building System Image

$ MACHINE="qemux86-64" DISTRO="mydistro" bitbake core-image-base

5.6. Testing In A VM

You should now see systemd in the serial output.

$ runqemu tmp/deploy/images/qemux86-64/core-image-base-qemux86-64.rootfs.qemuboot.conf \
          core-image-base \
          slirp \
          serialstdio

Your interactive BASH shell should look alot more colorful

$ cat < /place/where/you/injected/text/testing.txt