wipefile.c

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/*
* WIPEFILE.C - Destroys the contents of a file by writing over it
*	       multiple times.
*
* PROGRAMMER:	    Martti Ylikoski
* CREATED:	    1.12.1990
*/
static char *VERSION ="Version 1.1. Copyright (c) Martti Ylikoski, 1990, 1991." ;
/*
*/

#include <stdio.h>
#include <time.h>
#include <stdlib.h>
#include <string.h>
#include <param.h>
#include <paramstd.h>

static char *progname, *fname	;
extern unsigned long pflags ;

ParamEntry pentry[12] = {
     "P", &ParamSetPause, 0,
     "F", &ParamSetFold, 0,
     "V", &ParamSetVerbose, 1,
     "R", &ParamSetReport, 0,
     "S", &ParamSetSubDirs, 0,
     "?", &ParamSetHelp, 1,
     "H", &ParamSetHelp, 1,
     "NOD", &ParamSetNoDefault, 0,
     "TEST", &ParamSetTest, 1,
     "Y", &ParamSetYes, 1,
     "N", &ParamSetTest, 1,
     "\0", NULL, 0
} ;

ParamBlock params = {
    "/-",   IGNORECASE | NOPRIORITY | NOTRIGGERSALLOWED ,
    pentry
} ;

static int fhnd, writecnt = 1 ;

/* Macro to get a random integer within a specified range */
#define getrandom( min, max ) ((rand() % (int)(((max)+1) - (min))) + (min))

/* local prototypes */
static int wipefile (char *fname) ;

int main(int argc, char *argv[])
{
int i ;

   progname = argv[0] ;

   ParamHandle(&params, &argc, argv) ;

   if (pflags & PA_HELP || argc == 1)
   {
      printf("%s - destroy file by writing over it randomized data multiple times.\n", progname) ;
      puts(VERSION) ;
      puts("Usage: wipefile [ -count files | /H | /? | /TEST | /N] ") ;
      return( 1 ) ;
   }

   /* scan for overwrite count */
   for (i = 1 ; i < argc; i++)
   {
      if ( (argv[i][0] == '-' || argv[i][0] == '/') && strlen(argv[i]) > 1 )
	 writecnt = atoi(&argv[i][1]) ;
      else
	 fname = argv[i] ;
   }

   /* Seed the random number generator with current time. */
   srand( (unsigned)time( NULL ) );

   for (i=1 ; i <argc ; i++)
      if (argv[i][0] != '/' && argv[i][0] != '-')
	 wipefile(argv[i]) ;


}
/***********************************
*  wipefile() - destroy the contents of a file by writing over it multiple
*  times random data. This function assumes that the random number generator
*  has been initialized. The deleting is normally confirmed from user.
*
************************************/

static int wipefile (char *fname)
{
FILE *fptr ;
long lsize, li ;
int i, c ;

   if (pflags & PA_TEST)
   {
      printf("Would WIPE %s", fname) ;
      return( 0 ) ;
   }

   if ( (pflags & PA_YES) == 0)
   {
      printf("WIPE %s (Y/N) ?", fname) ;

      c = getchar() ;
      getchar() ; /* read past newline */
      if (c == 'Y'|| c == 'y')
      {
	 ;
      }
      else
      {
	 fprintf(stderr, "%s will not be wiped\n", fname) ;
	 return( 0 ) ;
      }
   }

   if (pflags & PA_VERBOSE)
      printf("WIPING %s ...\n", fname) ;

   /* open file */
   if ((fptr = fopen(fname, "rb+")) == NULL)
   {
      printf("%s: unable to open file %s for writing...\n", progname, fname) ;
      printf("Exiting...\n") ;
      return( 1 ) ;
   }

   /* determine size */
   fseek(fptr, 0L, SEEK_END);
   lsize = ftell (fptr) ;
   rewind(fptr) ;

   /* write multiple times over. */
   for (i = 0 ; i < writecnt ; i++)
   {
      /* write file full of random text */
      for (li = 0 ; li < lsize ; li++)
      {
	 fputc(getrandom(1,255), fptr) ;
      }
      rewind(fptr) ;
   }

   /* close file */
   fclose (fptr ) ;

   if (pflags & PA_VERBOSE)
      printf("WIPED!\n") ;
   return( 0 ) ;
}