/*
* libhugetlbfs - Easy use of Linux hugepages
* Copyright (C) 2013 Joonsoo Kim, LG Electronics.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/mman.h>
#include <hugetlbfs.h>
#include "hugetests.h"
#define P "corrupt-by-cow-opt"
#define DESC \
"* Test sanity of cow optimization on page cache. If a page *\n"\
"* in page cache has only 1 ref count, it is mapped for a private *\n"\
"* mapping directly and is overwritten freely, so next time we *\n"\
"* access the page, we can see corrupt data. *\n"\
int main(int argc, char *argv[])
{
long hpage_size;
int fd;
char *p;
char c;
test_init(argc, argv);
hpage_size = check_hugepagesize();
check_free_huge_pages(2);
fd = hugetlbfs_unlinked_fd();
if (fd < 0)
FAIL("hugetlbfs_unlinked_fd()");
p = mmap(NULL, hpage_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (p == MAP_FAILED)
FAIL("mmap() 1: %s", strerror(errno));
*p = 's';
verbose_printf("Write %c to %p via shared mapping\n", *p, p);
munmap(p, hpage_size);
p = mmap(NULL, hpage_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
if (p == MAP_FAILED)
FAIL("mmap() 2: %s", strerror(errno));
*p = 'p';
verbose_printf("Write %c to %p via private mapping\n", *p, p);
munmap(p, hpage_size);
p = mmap(NULL, hpage_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (p == MAP_FAILED)
FAIL("mmap() 3: %s", strerror(errno));
c = *p;
verbose_printf("Read %c from %p via shared mapping\n", *p, p);
munmap(p, hpage_size);
if (c != 's')
FAIL("data corrupt");
PASS();
}