freebsd-dev/tests/sys/vm/mlock_test.c

/*-
 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
 *
 * Copyright (c) 2019 Mark Johnston <markj@FreeBSD.org>
 *
 * 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.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include <sys/mman.h>
#include <sys/ptrace.h>
#include <sys/wait.h>

#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

#include <atf-c.h>

static void
test_wired_copy_on_write(void *addr, size_t len)
{
	int status, val;
	pid_t pid;

	pid = fork();
	if (pid == -1)
		atf_tc_fail("fork() failed: %s", strerror(errno));
	if (pid == 0) {
		if (mlock(addr, len) != 0)
			_exit(1);
		if (ptrace(PT_TRACE_ME, 0, NULL, 0) != 0)
			_exit(2);
		if (raise(SIGSTOP) != 0)
			_exit(3);
		if (munlock(addr, len) != 0)
			_exit(4);
		_exit(0);
	}

	ATF_REQUIRE(waitpid(pid, &status, 0) == pid);
	ATF_REQUIRE_MSG(!WIFEXITED(status),
	    "child exited with status %d", WEXITSTATUS(status));
	ATF_REQUIRE(WIFSTOPPED(status));
	ATF_REQUIRE(WSTOPSIG(status) == SIGSTOP);

	errno = 0;
	val = ptrace(PT_READ_D, pid, addr, 0);
	ATF_REQUIRE(errno == 0);
	ATF_REQUIRE(ptrace(PT_WRITE_D, pid, addr, val) == 0);
	ATF_REQUIRE(ptrace(PT_CONTINUE, pid, (caddr_t)1, 0) == 0);
	ATF_REQUIRE(waitpid(pid, &status, 0) == pid);
	ATF_REQUIRE(WIFEXITED(status));
	ATF_REQUIRE_MSG(WEXITSTATUS(status) == 0,
	    "child exited with status %d", WSTOPSIG(status));
}

/*
 * Use ptrace(2) to trigger a copy-on-write fault of anonymous memory.
 */
ATF_TC_WITHOUT_HEAD(mlock__copy_on_write_anon);
ATF_TC_BODY(mlock__copy_on_write_anon, tc)
{
	char *addr;
	int len;

	len = getpagesize();
	addr = mmap(NULL, len, PROT_READ, MAP_ANON, -1, 0);
	ATF_REQUIRE(addr != MAP_FAILED);

	test_wired_copy_on_write(addr, len);
}

/*
 * Use ptrace(2) to trigger a copy-on-write fault of a read-only text page.
 */
ATF_TC_WITHOUT_HEAD(mlock__copy_on_write_vnode);
ATF_TC_BODY(mlock__copy_on_write_vnode, tc)
{
	void *addr;
	int len;

	len = getpagesize();
	addr = (void *)((uintptr_t)test_wired_copy_on_write & ~(len - 1));

	test_wired_copy_on_write(addr, len);
}

/*
 * Try truncating and then resizing an mlock()ed mapping.
 */
ATF_TC_WITHOUT_HEAD(mlock__truncate_and_resize);
ATF_TC_BODY(mlock__truncate_and_resize, tc)
{
	char filename[16];
	char *addr;
	int fd, i, len;

	snprintf(filename, sizeof(filename), "tmp.XXXXXX");
	fd = mkstemp(filename);
	ATF_REQUIRE(fd >= 0);
	ATF_REQUIRE(unlink(filename) == 0);

	len = getpagesize();
	ATF_REQUIRE(ftruncate(fd, len) == 0);

	addr = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
	ATF_REQUIRE(addr != MAP_FAILED);
	ATF_REQUIRE(mlock(addr, len) == 0);
	memset(addr, 1, len);
	ATF_REQUIRE(ftruncate(fd, 0) == 0);
	ATF_REQUIRE(ftruncate(fd, len) == 0);
	for (i = 0; i < len; i++)
		ATF_REQUIRE(addr[i] == 0);
	ATF_REQUIRE(munlock(addr, len) == 0);
}

/*
 * Make sure that we can munlock() a truncated mapping.
 */
ATF_TC_WITHOUT_HEAD(mlock__truncate_and_unlock);
ATF_TC_BODY(mlock__truncate_and_unlock, tc)
{
	char filename[16];
	void *addr;
	int fd, len;

	snprintf(filename, sizeof(filename), "tmp.XXXXXX");
	fd = mkstemp(filename);
	ATF_REQUIRE(fd >= 0);
	ATF_REQUIRE(unlink(filename) == 0);

	len = getpagesize();
	ATF_REQUIRE(ftruncate(fd, len) == 0);

	addr = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
	ATF_REQUIRE(addr != MAP_FAILED);
	ATF_REQUIRE(mlock(addr, len) == 0);
	ATF_REQUIRE(ftruncate(fd, 0) == 0);
	ATF_REQUIRE(munlock(addr, len) == 0);
}

ATF_TP_ADD_TCS(tp)
{
	ATF_TP_ADD_TC(tp, mlock__copy_on_write_anon);
	ATF_TP_ADD_TC(tp, mlock__copy_on_write_vnode);
	ATF_TP_ADD_TC(tp, mlock__truncate_and_resize);
	ATF_TP_ADD_TC(tp, mlock__truncate_and_unlock);

	return (atf_no_error());
}