Re: Is there any way of getting the CAN interfaces list, from any C program?

[François <fbeaulier@orange.fr>]

Stephane,

This is what i have done in a open source project i have started, a web 
can analyzer called ewecan (https://bitbucket.org/Mongo/ewecan):
It parses /sys/class/net but unfortunately, as noted in comments, it 
cannot make the difference between up or down interfaces.

/* Get a list of available socketcan interfaces and return them in
    a string as a JS array like ["can0", "can1", "vcan"]
    Returned string must be freed after use
    BUG : it also returns interfaces that are present but down !
*/
char *cmd_listitf(void)
{
     char *buf = malloc(255);
     if(!buf)
         return NULL;
     /* looking for socketcan interfaces in /sys */
     DIR *fdir = opendir("/sys/class/net");
     if(fdir == NULL){
         perror("opendir");
         free(buf);
         return NULL;
     }
     struct dirent *fic;
     int firstdone = 0;
     buf[0] = '[';
     buf[1] = '\0';
     while(1){
         fic = readdir(fdir);
         if(fic == NULL)
             break;
         if(!strstr(fic->d_name, "can"))
             continue;
         /* if the new string does not fit in buf, stop here */
         if((strlen(fic->d_name) + strlen(buf) + 4) >= 255)
             break;
         if(firstdone)
             strcat(buf, ",");
         strcat(buf, "\"");
         strcat(buf, fic->d_name);
         strcat(buf, "\"");
         firstdone = 1;
     }
     strcat(buf, "]");
     closedir(fdir);
     return buf;
}

Hope it can help !

Regards

--
François Beaulier
www.ingelibre.fr

Le 24/04/2013 11:06, Stephane Grosjean a écrit :
> Hi linux-can members,
>
> I currently wonder whether it exists any way of getting the list of 
> the installed CAN interfaces, from a C program?
> I mean, getting the network interfaces list is available using 
> ioctl(SIOCGIFCONF).
> But AFAIK, this (only) returns the IP interfaces found in the system, 
> even using a socket CAN file descriptor.
> And, I would also like to avoid some pipe/fork/grep/sed in this C 
> program too ;-)
>
> Thanks for your help and best regards,
>
> Stéphane
> -- 
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