How to execute a different binary on run-time in Contiki OS?

Question

I am trying to make a sensor that runs on Contiki OS to execute a new binary and replace the current one, if an event occurs.

I am using Cooja simulator and sky note and I uploaded the binary into the coffee file system of the node(using cooja script) and I want to execute the hello-world.ce

To compile my current program(reboot.c) that i will dynamicaly load a module from I used the following commands:

1. make TARGET=sky clean CLEAN=symbols.?
2. make reboot.sky TARGET=sky
3. make CORE=reboot.sky TARGET=sky reboot.sky

And for the hello-world that will be loaded I used:

1. make TARGET=sky hello-world.ce

Here is part of my code (reboot.c) from where i am trying to execute hello-world

#include "contiki.h"
#include "core/loader/elfloader.h"
#include "cfs/cfs.h"

PROCESS(hello_world_process, "Reboot process");
AUTOSTART_PROCESSES(&hello_world_process);
/*---------------------------------------------------------------------------*/
PROCESS_THREAD(hello_world_process, ev, data)
{
    PROCESS_BEGIN();

    int i;
    int binFile,ret;

    elfloader_init();

    binFile=cfs_open("hello-world.ce",CFS_READ);
    printf("cfs_open:%d\n",binFile); //returns 0 so the file is opened

    ret=elfloader_load(binFile);
    cfs_close(binFile);
    printf("loader returned: %d\n",ret); //returns 0 ->meaning everything is ok

    if(ret == ELFLOADER_OK){
        printf("elf OK\n");
        for(i=0; elfloader_autostart_processes[i] != NULL; i++) {
            printf("exec: starting process %s. \n", elfloader_autostart_processes[i]->name);
        }
        autostart_start(elfloader_autostart_processes);
    }

    printf("end of rebooting program\n”);
    PROCESS_END();
}

It seems that the elfloader_autostart_processes is set to null since the print statement is not executed in the for loop. The program continues and prints "end of rebooting program" and I was expecting it to print hello-world as an indicator that the binary has been loaded and started.

Can you provide any help?

Melodramatize

Could you share more of your code? This as it is doesn't have enough surrounding context to convey the problem clearly. – Cullie

Yeah I added the whole code that I am currently using. This code is just a minor independent project that I am trying to implement. – Melodramatize

Where and how is elfloader_autostart_processes data structure definied and initialized? – Calamine

Furthermore, I assume that ret == ELFLOADER_OK is true so you get to the for loop at all? – Calamine

@Calamine Yes it is true The elfloader_autostart_processes is defined at the header of core/loader/elfloader.h and it is initialised from the library as far as I know – Melodramatize

Answer 1

I manage to achieve it using another build in library of Contiki. Specifically I used shell-exec.c that is responsible to execute files and I gave it as an argument the file that I wanted to be executed on run-time. I used a Cooja script to upload the file on the sensor in Cooja simulator.

#include "contiki.h"
#include "shell-exec.c"
#include "serial-shell.h"
#include "cfs/cfs.h"

#include <stdio.h> /* For printf() */
/*---------------------------------------------------------------------------*/
PROCESS(rebooting, "Reboot process");
AUTOSTART_PROCESSES(&rebooting);
/*---------------------------------------------------------------------------*/
PROCESS_THREAD(rebooting, ev, data)
{
  PROCESS_BEGIN();
    
    static struct etimer et;
    /* Allow some time for the file to upload using cooja. */
    etimer_set(&et, 10 * CLOCK_SECOND);
    PROCESS_WAIT_UNTIL(etimer_expired(&et));

    process_start(&shell_exec_process,"hello-world.ce\0");
    

  PROCESS_END();
}

Cooja Script

WAIT_UNTIL(msg.startsWith('Starting'));
log.log("Mote started\n");
mymote = mote; /* store mote reference */

fs = mote.getFilesystem();

DIR="~/hello-world"; /* Directory that the binary is stored in the host machine running cooja */

mote_file=DIR+ "hello-world.ce";

ret=fs.insertFile(mote_file);

log.log("inserted");

Melodramatize