Get the working sectors of a block device. Uses the output of bad sectors created by badblocks. Thanks to @nikp123

get_working_sectors.c

#include <stdio.h>

int main(int argc, char *argv[]) {
    FILE *fp = fopen(argv[1], "rb");
    if(!fp) return 1;
   
    int last = 0, bigdiff = 0, num;
    while(fscanf(fp, "%d", &num) > 0){ 
        if((num - last) > bigdiff) {
            printf("Overthrow: %#x > %#x (%#x-%#x)\n", num-last, bigdiff, last, num);
            bigdiff = num - last;
        }
        last = num;
    }
    return 0;
}