urandom.c
author Markus Bröker <mbroeker@largo.dyndns.tv>
Sat, 13 Dec 2008 17:58:00 +0100
changeset 8 96d16dfe787a
parent 0 af501b0c1716
child 9 c3fecc82ade6
permissions -rw-r--r--
We use return EXIT_SUCCESS instead of return 0 committer: Markus Bröker <mbroeker@largo.homelinux.org>
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
0
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
     1
/**
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
     2
 *     $Id: urandom.c,v 1.1.1.1 2008-04-28 17:32:53 mbroeker Exp $
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
     3
 * $Source: /development/c/demos/urandom.c,v $
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
     4
 *
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
     5
 */
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
     6
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
     7
#include <stdio.h>
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
     8
#include <stdlib.h>
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
     9
#include <fcntl.h>
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    10
#include <unistd.h>
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    11
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    12
int compare (unsigned char *a, unsigned char *b)
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    13
{
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    14
    if (*a > *b)
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    15
        return 1;
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    16
    return -1;
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    17
}
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    18
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    19
int main (int argc, char **argv)
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    20
{
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    21
    int i;
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    22
    int elements;
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    23
    int fd;
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    24
    unsigned char numbers[256] = { 0 };
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    25
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    26
    fd = open ("/dev/urandom", O_RDONLY);
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    27
    if (fd == -1)
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    28
        return EXIT_FAILURE;
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    29
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    30
    elements = read (fd, numbers, 255);
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    31
    numbers[elements] = 0;
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    32
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    33
    qsort (numbers, elements, sizeof (unsigned char), (void *)&compare);
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    34
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    35
    for (i = 0; i < elements; i++) {
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    36
        printf ("Number: %d\n", numbers[i]);
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    37
    }
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    38
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    39
    close (fd);
8
96d16dfe787a We use return EXIT_SUCCESS instead of return 0
Markus Bröker <mbroeker@largo.dyndns.tv>
parents: 0
diff changeset
    40
0
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    41
    return EXIT_SUCCESS;
af501b0c1716 demos cvs copy
Markus Bröker <mbroeker@largo.dyndns.tv>
parents:
diff changeset
    42
}