I am creating a C program. I mainly care about unix/linux systems but including windows here would be ideal. I want to find an approximately unique identifier for a networked machine. I am wondering if there is a better solution than finding a MAC address. The fact that MAC addresses can be duplicated is not necessarily a deal breaker. One might do something like this (yes, I know this is not portable; yes I know rand isn't really random, this just for demonstration):
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <linux/if.h>
#include <netdb.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <stdlib.h>
int main()
{
struct ifreq s;
int fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_IP);
srand(time(NULL));
strcpy(s.ifr_name, "wlp0s20f3");
if (0 == ioctl(fd, SIOCGIFHWADDR, &s)) {
int i;
for (i = 0; i < 6; ++i)
printf("%x", (unsigned char) s.ifr_addr.sa_data[i]);
printf("%d\n",rand() % 200);
return 0;
}
return 1;
}
But is there some other mechanism that might be considered?
Are there any "gotchas" to dynamically creating header variables during make that are then compiled into the binary later in the make process?
