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/*
* Copyright (C) 2013-2017 Canonical, Ltd.
*
* 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 (at your option) 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.
*
* This code is a complete clean re-write of the stress tool by
* Colin Ian King <colin.king@canonical.com> and attempts to be
* backwardly compatible with the stress tool by Amos Waterland
* <apw@rossby.metr.ou.edu> but has more stress tests and more
* functionality.
*
*/
#include "stress-ng.h"
/*
* stress_zero
* stress reading of /dev/zero
*/
int stress_zero(
uint64_t *const counter,
const uint32_t instance,
const uint64_t max_ops,
const char *name)
{
int fd;
const size_t page_size = stress_get_pagesize();
(void)instance;
if ((fd = open("/dev/zero", O_RDONLY)) < 0) {
pr_fail_err(name, "open");
return EXIT_FAILURE;
}
do {
char buffer[page_size];
ssize_t ret;
#if defined(__linux__)
int32_t *ptr;
#endif
ret = read(fd, buffer, sizeof(buffer));
if (ret < 0) {
if ((errno == EAGAIN) || (errno == EINTR))
continue;
pr_fail_err(name, "read");
(void)close(fd);
return EXIT_FAILURE;
}
#if defined(__linux__)
/*
* check if we can mmap /dev/zero
*/
ptr = mmap(NULL, page_size, PROT_READ, MAP_SHARED | MAP_ANONYMOUS,
fd, page_size * mwc16());
if (ptr == MAP_FAILED) {
if (errno == ENOMEM)
continue;
pr_fail_err(name, "mmap /dev/zero");
(void)close(fd);
return EXIT_FAILURE;
}
/* Quick sanity check if first 32 bits are zero */
if (*ptr != 0) {
pr_fail_err(name, "mmap'd /dev/zero not null");
(void)munmap(ptr, page_size);
(void)close(fd);
return EXIT_FAILURE;
}
(void)munmap(ptr, page_size);
#endif
(*counter)++;
} while (opt_do_run && (!max_ops || *counter < max_ops));
(void)close(fd);
return EXIT_SUCCESS;
}
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