Mastering Embedded Linux Programming

BusyBox init

BusyBox has a minimal init program that uses a configuration file, /etc/inittab, to define rules to start programs at boot up and to stop them at shutdown. Usually, the actual work is done by shell scripts which, by convention, are placed in the /etc/init.d directory.

init begins by reading the configuration file, /etc/inittab. This contains a list of programs to run, one per line, with this format:

<id>::<action>:<program>

The role of these parameters is as follows:

• id: The controlling terminal for the command
• action: The conditions to run this command, as shown in the following paragraph
• program: The program to run

The actions are as follows:

• sysinit: Run the program when init starts, before any of the other types of actions.
• respawn: Run ...