hyperase.c

/*
* Author: Charles Averill
* WARNING: Don't run this on anything important
*/

#define _GNU_SOURCE

#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <sys/statvfs.h>
#include <sys/random.h>

int main(int argc, char *argv[]){
	// Check arguments
	if(argc != 2){
		printf("Usage: hyperase DRIVE\n");
		return 1;
	}

	char *fn = argv[1];

	// Warnings
	printf("\033[31mWARNING: THIS PROGRAM WILL ATTEMPT TO OVERWRITE EVERY BYTE ON THE PROVIDED PARTITION %s\n", fn);
	printf("THIS OPERATION COULD BE COMPLETELY IRREVERSIBLE\n");

	// Confirmation
	char correct_confirmation[300] = "\0";
	strcat(correct_confirmation, "I WOULD LIKE TO ERASE ");
	strcat(correct_confirmation, fn);
	strcat(correct_confirmation, "\n\0");

	printf("IF YOU WOULD LIKE TO COMPLETELY ERASE THIS PARTITION, ENTER \"I WOULD LIKE TO ERASE {partition_name}\": ");
	printf("\033[0m");
	fflush(stdout);
	
	char confirmation[300] = "\0";
	read(0, confirmation, 300);
	if(strcmp(confirmation, correct_confirmation)){
		printf("Exiting\n");
		return 1;
	}

	// Delay
	printf("You have 5 seconds to interrupt this script\n");
	for(int i = 0; i < 5; i++){
		printf("%d\n", 5 - i);
		sleep(1);
	}

	// Open partition
	FILE *fp = fopen(fn, "r+b");

	if(fp == NULL){
		perror("Error opening partition");
		return 1;
	}

	// Get partition size
	fseek(fp, 0, SEEK_END); 
	long long int size = ftell(fp);
	printf("%lld\n", size);
	
	// Erase
	size_t blksize = size > 512 ? 512 : size;
	long long int n_blks = size / blksize;
	char rnd[blksize];

	for(int i = 1; i < 51; i++){
		rewind(fp);
		printf("Erase #%d\n", i);
		for(int x = 0; x < n_blks; x++){
			// Fill each block with random bytes
			if(getrandom(rnd, blksize, GRND_RANDOM) == -1){
				perror("getrandom error");
				return 1;
			}
			if(fwrite(rnd, 1, blksize, fp) == -1){
				perror("write error");
				return 1;
			}
		}
	}

	fclose(fp);

	return 0;
}