Date: Thu, 5 Nov 2020 07:59:06 +0000 (UTC) From: Peter Holm <pho@FreeBSD.org> To: src-committers@freebsd.org, svn-src-user@freebsd.org Subject: svn commit: r367363 - user/pho/stress2/tools Message-ID: <202011050759.0A57x6E5070943@repo.freebsd.org>
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Author: pho Date: Thu Nov 5 07:59:05 2020 New Revision: 367363 URL: https://svnweb.freebsd.org/changeset/base/367363 Log: Add a helper tool for file system tests. Added: user/pho/stress2/tools/flip.c Added: user/pho/stress2/tools/flip.c ============================================================================== --- /dev/null 00:00:00 1970 (empty, because file is newly added) +++ user/pho/stress2/tools/flip.c Thu Nov 5 07:59:05 2020 (r367363) @@ -0,0 +1,121 @@ +/*- + * SPDX-License-Identifier: BSD-2-Clause-FreeBSD + * + * Copyright (c) 2020 Peter Holm <pho@FreeBSD.org> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +/* + * Flip one or more bits in a file. + */ + +#include <sys/types.h> +#include <sys/stat.h> + +#include <err.h> +#include <fcntl.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +extern char *optarg; +extern int optind; + +static long +random_long(long mi, long ma) +{ + return (arc4random() % (ma - mi + 1) + mi); +} + +static void +flip(void *ap, size_t len) +{ + unsigned char *cp; + int byte; + unsigned char bit, buf, mask, old; + + cp = (unsigned char *)ap; + byte = random_long(0, len); + bit = random_long(0,7); + mask = ~(1 << bit); + buf = cp[byte]; + old = cp[byte]; + buf = (buf & mask) | (~buf & ~mask); + cp[byte] = buf; +#if defined(DEBUG) + printf("Change %2x to %2x at %d by flipping bit %d\n", + old, buf, byte, bit); +#endif +} + +int +main(int argc, char *argv[]) +{ + struct stat st; + off_t pos; + int fd, i, times; + char c; + + times = 1; + while ((c = getopt(argc, argv, "n:")) != -1) { + switch (c) { + case 'n': + times = atoi(optarg); + break; + case '?': + default: + fprintf(stderr, + "Usage: %s [ -n <num> <file>]\n", + argv[0]); + exit(1); + } + } + argc -= optind; + argv += optind; + + if (argc != 1) { + fprintf(stderr, "Missing file name\n"); + exit(1); + } + + if ((fd = open(argv[0], O_RDWR)) == -1) + err(1, "open(%s)", argv[0]); + + if (fstat(fd, &st) == -1) + err(1, "stat %s", argv[0]); + + for (i = 0; i < times; i++) { + pos = arc4random() % st.st_size; + if (lseek(fd, pos, SEEK_SET) == -1) + err(1, "lseek()"); + read(fd, &c, 1); + flip(&c, 1); + if (lseek(fd, pos, SEEK_SET) == -1) + err(1, "lseek()"); + write(fd, &c, 1); + } + + return (0); +}
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