1/*
2 * Copyright (c) 2003-2012 Tim Kientzle
3 * Copyright (c) 2012 Andres Mejia
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#include "test_utils.h"
28
29#include <errno.h>
30#include <stdlib.h>
31#include <stdio.h>
32#include <string.h>
33#include <assert.h>
34
35static inline uint64_t
36xorshift64(uint64_t *state)
37{
38	uint64_t x = *state;
39	x ^= x << 13;
40	x ^= x >> 7;
41	x ^= x << 17;
42	*state = x;
43	return (x);
44}
45
46/*
47 * Fill a buffer with reproducible pseudo-random data using a simple xorshift
48 * algorithm. Originally, most tests filled buffers with a loop that calls
49 * rand() once for each byte. However, this initialization can be extremely
50 * slow when running on emulated platforms such as QEMU where 16M calls to
51 * rand() take a long time: Before the test_write_format_7zip_large_copy test
52 * took ~22 seconds, whereas using a xorshift random number generator (that can
53 * be inlined) reduces it to ~17 seconds on QEMU RISC-V.
54 */
55static void
56fill_with_pseudorandom_data_seed(uint64_t seed, void *buffer, size_t size)
57{
58	uint64_t *aligned_buffer;
59	size_t num_values;
60	size_t i;
61	size_t unaligned_suffix;
62	size_t unaligned_prefix = 0;
63	/*
64	 * To avoid unaligned stores we only fill the aligned part of the buffer
65	 * with pseudo-random data and fill the unaligned prefix with 0xab and
66	 * the suffix with 0xcd.
67	 */
68	if ((uintptr_t)buffer % sizeof(uint64_t)) {
69		unaligned_prefix =
70		    sizeof(uint64_t) - (uintptr_t)buffer % sizeof(uint64_t);
71		aligned_buffer =
72		    (uint64_t *)((char *)buffer + unaligned_prefix);
73		memset(buffer, 0xab, unaligned_prefix);
74	} else {
75		aligned_buffer = (uint64_t *)buffer;
76	}
77	assert((uintptr_t)aligned_buffer % sizeof(uint64_t) == 0);
78	num_values = (size - unaligned_prefix) / sizeof(uint64_t);
79	unaligned_suffix =
80	    size - unaligned_prefix - num_values * sizeof(uint64_t);
81	for (i = 0; i < num_values; i++) {
82		aligned_buffer[i] = xorshift64(&seed);
83	}
84	if (unaligned_suffix) {
85		memset((char *)buffer + size - unaligned_suffix, 0xcd,
86		    unaligned_suffix);
87	}
88}
89
90void
91fill_with_pseudorandom_data(void *buffer, size_t size)
92{
93	uint64_t seed;
94	const char* seed_str;
95	/*
96	 * Check if a seed has been specified in the environment, otherwise fall
97	 * back to using rand() as a seed.
98	 */
99	if ((seed_str = getenv("TEST_RANDOM_SEED")) != NULL) {
100		errno = 0;
101		seed = strtoull(seed_str, NULL, 10);
102		if (errno != 0) {
103			fprintf(stderr, "strtoull(%s) failed: %s", seed_str,
104			    strerror(errno));
105			seed = rand();
106		}
107	} else {
108		seed = rand();
109	}
110	fill_with_pseudorandom_data_seed(seed, buffer, size);
111}
112