/*
 * nuke.c
 *
 * this is a secure file deletion command
 * written by Giovanni Gigante, 4 march 1994, V 1.0
 * this code is freeware
 *
 * CAUTION: read the enclosed document before using.
 *
 */

#include <stdio.h>
#include <stdlib.h>

#define N_PASSES 3
#define EXIT_BAD 20
#define EXIT_WARN 10

void main(int argc, char *argv[]) {
	
	FILE *fp;
	long length;
	int i,j;
	const char version[]="$VER: 1.0 950304";
        const int fill[N_PASSES]={0x00,0xff,0x00};

	/* check CLI syntax */
	if (argc != 2) {
		fprintf(stderr,"Nuke 1.0 by Giovanni Gigante\n");
                fprintf(stderr,"Usage: %s <filename>\n",argv[0]);
		exit(EXIT_BAD);
	}
	
	/* open file and get its length*/
	if(!(fp=fopen(argv[1],"r"))) {
		fprintf(stderr,"Cannot open %s\n",argv[1]);
		exit(EXIT_BAD);
	}
	if(fseek(fp,0,SEEK_END)) exit(EXIT_BAD);
	length=ftell(fp);
	
	/* overwrite file several times */
        for(j=0; j<N_PASSES; j++) {
        	if(!(fp=freopen(argv[1],"w",fp))) {
	        	fprintf(stderr,"Cannot reopen %s at pass %d\n",argv[1],j);
        		exit(EXIT_BAD);
        	}
        	for(i=0; i<=length; i++) {
                        if (fputc(fill[j],fp)==EOF) {
        		        fprintf(stderr,"Cannot write to %s\n",argv[1]);
                		exit(EXIT_BAD);
                        }
                }
                fclose(fp);
        }

	/* delete file */
	if(remove(argv[1])) {
		fprintf(stderr,"%s  overwritten, but cannot be deleted\n",argv[1]);
		exit(EXIT_WARN);
	}

	fprintf(stderr,"%s  Nuked.\n",argv[1]);
} /*main*/