entropy_sample.c

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/*
 * Copyright (C) 2012 Michael Brown <mbrown@fensystems.co.uk>.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 *
 * You can also choose to distribute this program under the terms of
 * the Unmodified Binary Distribution Licence (as given in the file
 * COPYING.UBDL), provided that you have satisfied its requirements.
 */
 
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 
/** @file
 *
 * Entropy sampling
 *
 */
 
#include <stdio.h>
#include <ipxe/entropy.h>
#include <ipxe/test.h>
 
/** Total number of test samples */
#define SAMPLE_COUNT 65536
 
/** Number of samples per block */
#define SAMPLE_BLOCKSIZE 256
 
/**
 * Generate entropy samples for external testing
 *
 * @v source            Entropy source
 */
static void entropy_sample ( struct entropy_source *source ) {
        static noise_sample_t samples[SAMPLE_BLOCKSIZE];
        unsigned int i;
        unsigned int j;
        int rc;
 
        /* Collect and print blocks of samples */
        for ( i = 0 ; i < ( SAMPLE_COUNT / SAMPLE_BLOCKSIZE ) ; i++ ) {
 
                /* Collect one block of samples */
                rc = entropy_enable ( source );
                ok ( rc == 0 );
                for ( j = 0 ; j < SAMPLE_BLOCKSIZE ; j++ ) {
                        rc = get_noise ( source, &samples[j] );
                        ok ( rc == 0 );
                }
                entropy_disable ( source );
 
                /* Print out sample values */
                for ( j = 0 ; j < SAMPLE_BLOCKSIZE ; j++ ) {
                        printf ( "SAMPLE %s %d %d\n", source->name,
                                 ( i * SAMPLE_BLOCKSIZE + j ), samples[j] );
                }
        }
}
 
/**
 * Generate entropy samples for external testing
 *
 */
static void entropy_sample_test_exec ( void ) {
        struct entropy_source *source;
 
        /* Test each entropy source */
        for_each_table_entry ( source, ENTROPY_SOURCES ) {
                entropy_sample ( source );
        }
}
 
/** Entropy sampling self-test */
struct self_test entropy_sample_test __self_test = {
        .name = "entropy_sample",
        .exec = entropy_sample_test_exec,
};