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Make the C++ program auto-start on boot

This document demonstrates how to set a program to launch automatically at startup.

Method 1: Write a startup script​

ReCamera uses a lightweight SysVinit system and performs initialization via /etc/inittab. When recamera is powered on, it reads the contents of inittab which starts the /etc/init.d/rcS with the following code:

# now run any rc scripts
::sysinit:/etc/init.d/rcS

The rcS file defines that the program will sequentially start scripts beginning with "S??":

for i in /etc/init.d/S??* ;do

     # Ignore dangling symlinks (if any).
     [ ! -f "$i" ] && continue

     case "$i" in
	*.sh)
	    # Source shell script for speed.
	    (
		trap - INT QUIT TSTP
		set start
		. $i
	    )
	    ;;
	*)
	    # No sh extension, so fork subprocess.
	    $i start
	    ;;
    esac
done

In the /etc/init.d directory, you can add your program's auto-start script.(Scripts prefixed with "S" followed by a number, the number determine their boot execution order.)

Name example:

  • S10network: Starts early (lower number = earlier execution)
  • S99myprogram: Starts late (higher number = later execution)

The content of the auto-start script must include:

  • Variable Definition Section
    • It defines configuration parameters required for service operation.
    • Key Variables:
      • DAEMON: Path to the executable file
      • PIDFILE: Location of the process ID record file
      • LD_LIBRARY_PATH: Custom library path
  • Functional Functions Section
    • It includes four main functions:
      • start(): Starts the service
      • stop(): Stops the service
      • restart(): Restarts the service
      • status(): Checks service status
  • Main Control Logic
    • It calls the corresponding function based on input arguments.

You can refer to existing scripts to write your own script. Here is an example of sccma-node for reference:

#!/bin/sh

### BEGIN INIT INFO
# Provides:          sscma-node
# Required-Start:    $all
# Required-Stop:     $all
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: Start SSCMA Node at boot time
# Description:       Start SSCMA Node service.
### END INIT INFO

DAEMON=/usr/local/bin/sscma-node
DAEMON_OPTS="--start"
NAME=sscma-node
DESC="SSCMA Node Service"
PIDFILE=/var/run/$NAME.pid
LOGFILE=/var/log/$NAME.log
USER=root

# Set up the library path if necessary
LD_LIBRARY_PATH=/mnt/system/lib:/mnt/system/usr/lib:/mnt/system/usr/lib/3rd:$LD_LIBRARY_PATH
export LD_LIBRARY_PATH

start() {
    echo "Starting $DESC: $NAME"
    if [ -f $PIDFILE ]; then
        PID=$(cat $PIDFILE)
        if [ -n "$PID" ] && kill -0 "$PID" 2>/dev/null; then
            echo "$NAME is already running (PID: $PID)."
            return 1
        else
            echo "Removing stale PID file."
            rm -f $PIDFILE
        fi
    fi
    start-stop-daemon -S -q -m -b -p $PIDFILE --exec $DAEMON -- $DAEMON_OPTS
    [ $? = 0 ] && echo "OK" || echo "FAIL"
}

stop() {
    echo "Stopping $DESC: $NAME"
    if [ -f $PIDFILE ]; then
        PID=$(cat $PIDFILE)
        if [ -n "$PID" ] && kill -0 "$PID" 2>/dev/null; then
            start-stop-daemon -K -q -p $PIDFILE
            rm -f $PIDFILE
            [ $? = 0 ] && echo "OK" || echo "FAIL"
        else
            echo "Process not running but PID file exists, cleaning up."
            rm -f $PIDFILE
        fi
    else
        echo "$NAME is not running."
    fi
}

restart() {
    stop
    start
}

status() {
    if [ -f $PIDFILE ]; then
        PID=$(cat $PIDFILE)
        if [ -n "$PID" ] && kill -0 "$PID" 2>/dev/null; then
            echo "$NAME is running (PID: $PID)."
        else
            echo "$NAME PID file exists but process is not running."
        fi
    else
        echo "$NAME is not running."
    fi
}

case "$1" in
    start)
        start
        ;;
    stop)
        stop
        ;;
    restart)
        restart
        ;;
    status)
        status
        ;;
    *)
        echo "Usage: $0 {start|stop|restart|status}"
        exit 1
        ;;
esac

exit 0

Then, grant executable permissions to your script:

sudo chmod +x {your script}
ls -l

Place your program's executable file in the specified path, typically: /usr/local/bin:

sudo scp {your program} /usr/local/bin
sudo chmod +x {your program}
ls -l

Test whether the script and program can start normally:

sudo /etc/init.d/{your script} start
cd /usr/local/bin
sudo {your program}

If successed, restart your recamera.

Method 2: Install the C++ project using opkg.​

You can also pre-configure the auto-start script within your C++ project ,then install it on the recamera.

Add the Control directory

In your project, you need to include the following control scripts:

  • preinst (Pre-installation Script)
    • It executes before the package is installed.The function of this script is:
      • Check if the system meets installation requirements
      • Stop old version services that will be replaced
      • Backup existing configuration files
      • Verify dependencies are satisfied
      • Create necessary system users/groups
      • Execution Timing: Runs during dpkg -i or apt install, before files are deployed.

For example:

#!/bin/sh
set -e

if [ -f /etc/init.d/S93sscma-supervisor ]; then
    /etc/init.d/S93sscma-supervisor stop
fi

exit 0
  • postinst (Post-installation Script)
    • It executes after the package is fully installed.The function of this script is:
      • Start newly installed services
      • Update system caches or databases (e.g., ldconfig, update-rc.d)
      • Run initial configuration steps
      • Set file permissions/ownership
      • Update alternatives system (e.g., update-alternatives)
      • Display post-installation instructions
      • Execution Timing:Runs during dpkg -i or apt install, after all files are deployed.

For example:

#!/bin/sh
set -e

if [ -f /etc/init.d/S93sscma-supervisor ]; then
    /etc/init.d/S93sscma-supervisor start   
fi


exit 0
  • prerm (Pre-removal Script)
    • It executes before the package is uninstalled.The function of this script is:
      • Stop related services gracefully
      • Check if processes are using the software (prevent forced removal)
      • Backup user data before deletion
      • Clean up temporary files or runtime resources
      • Execution Timing:Runs during dpkg -r or apt remove, before files are deleted.

For example:

#!/bin/sh
set -e

if [ -f /etc/init.d/S93sscma-supervisor ]; then
    /etc/init.d/S93sscma-supervisor stop
fi

exit 0

Add the rootfs directory

Then put the auto-start script into the corresponding path:

Put the entire project into a Linux cross-compilation environment for compilation and packaging. Before packaging, you must check whether the files are in Linux-compatible LF line ending format. If CRLF format (Windows-style) is found, convert them first.

dos2unix {your files}

Then,

cd {your project}
cmake -B build -DCMAKE_BUILD_TYPE=Release .
cmake --build build
cd build && cpack
scp {your project.deb} [email protected]:/tmp/

In the recamera terminal,use opkg to install:

sudo opkg install /tmp/{your project.deb}

If your project was previously installed, uninstall it first.

sudo opkg remove {your program}

sudo opkg install /tmp/{your project.deb}

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