Home | History | Annotate | Line # | Download | only in test_utils 
      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 
     35 static inline uint64_t
     36 xorshift64(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  */
     55 static void
     56 fill_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 
     90 void
     91 fill_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 
    113 unsigned long
    114 bitcrc32(unsigned long c, const void *_p, size_t s)
    115 {
    116 	/* This is a drop-in replacement for crc32() from zlib.
    117 	 * Libarchive should be able to correctly read archives (including
    118 	 * correct CRCs) even when zlib is unavailable, and this function
    119 	 * helps us verify that. Yes, this is very, very slow and unsuitable
    120 	 * for production use, but it's obviously correct, compact, and
    121 	 * works well enough for this particular usage. Libarchive
    122 	 * internally uses a much more efficient implementation if zlib is
    123 	 * unavailable. */
    124 	const unsigned char *p = _p;
    125 	char bitctr;
    126 
    127 	if (p == NULL)
    128 		return (0);
    129 
    130 	for (; s > 0; --s) {
    131 		c ^= *p++;
    132 		for (bitctr = 8; bitctr > 0; --bitctr) {
    133 			if (c & 1) c = (c >> 1);
    134 			else	   c = (c >> 1) ^ 0xedb88320;
    135 			c ^= 0x80000000;
    136 		}
    137 	}
    138 	return (c);
    139 }
    140 
    141 /* Read little-endian integers */
    142 unsigned short
    143 i2le(const void* p_)
    144 {
    145 	const unsigned char *p = p_;
    146 	return (p[0] | (p[1] << 8));
    147 }
    148 unsigned int
    149 i4le(const void* p_)
    150 {
    151 	const char *p = p_;
    152 	return (i2le(p) | (i2le(p + 2) << 16));
    153 }
    154 unsigned long long
    155 i8le(const void* p_)
    156 {
    157 	const char *p = p_;
    158 	return (i4le(p) | ((unsigned long long)i4le(p + 4) << 32));
    159 }
    160