Attachment 592185 Details for Bug 832531 – Small C program to quickly generate large amounts of random data.

Small C program to quickly generate large amounts of random data.

semi_random.c (text/plain), 1.04 KB, created by Richard Ryniker on 2012-06-15 16:39:38 UTC

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Creator: Richard Ryniker

Created: 2012-06-15 16:39:38 UTC

Size: 1.04 KB

patch

obsolete

>/* Generate lots of random numbers, when high quality is not required. 
>   The intention is to provide a high-speed source of noise bytes suitable for
>   initialization of disk space which will be used for encrypted file systems.
>
>   Example:  to fill a disk partion such as /dev/sdi1 with noise bytes, use
>
>      semi_random | dd bs=1024k of=/dev/sdi1
>
>*/
>
>#include <stdio.h>
>#include <stdlib.h>
>
>#define rdata_size (1024 * 1024)
>
>
>int main(int argc, char **argv)
>{
>  unsigned char     rdata[rdata_size+sizeof(int)];
>  long                rdx;
>  unsigned int       seed, x, tmp;
>  FILE                 *u;
>
>  u = fopen("/dev/urandom", "r");
>  if (! u) {
>    fprintf(stderr, "Cannot open /dev/urandom\n");
>    exit(1);}
>
>
>  while (1) {
>
>    if (! fread(&seed, sizeof(seed), 1, u)) {
>      fprintf(stderr, "Read failure\n");
>      exit(2);}
>
>    srand(seed);
>
>    for (rdx=0; rdx<sizeof(rdata); rdx += sizeof(int)) {
>      tmp =  rand();
>      for (x=0; x<sizeof(int); x++) {
>	rdata[rdx+x] = tmp;
>	tmp >>= 8; }
>    }
>    fwrite(rdata, sizeof(rdata), 1, stdout);}
>}

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Attachments on bug 832531: 592185 | 592223 | 592226