tools/testing/selftests/futex/functional/futex_wait.c

Source file repositories/reference/linux-study-clean/tools/testing/selftests/futex/functional/futex_wait.c

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/futex/functional/futex_wait.c
Extension
.c
Size
3467 bytes
Lines
147
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: implementation source
Status
source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright Collabora Ltd., 2021
 *
 * futex cmp requeue test by André Almeida <andrealmeid@collabora.com>
 */

#include <pthread.h>
#include <sys/shm.h>
#include <sys/mman.h>
#include <fcntl.h>

#include "futextest.h"
#include "kselftest_harness.h"

#define timeout_ns  30000000
#define WAKE_WAIT_US 10000
#define SHM_PATH "futex_shm_file"

void *futex;

static void *waiterfn(void *arg)
{
	struct timespec to;
	unsigned int flags = 0;

	if (arg)
		flags = *((unsigned int *) arg);

	to.tv_sec = 0;
	to.tv_nsec = timeout_ns;

	if (futex_wait(futex, 0, &to, flags))
		printf("waiter failed errno %d\n", errno);

	return NULL;
}

TEST(private_futex)
{
	unsigned int flags = FUTEX_PRIVATE_FLAG;
	u_int32_t f_private = 0;
	pthread_t waiter;
	int res;

	futex = &f_private;

	/* Testing a private futex */
	ksft_print_dbg_msg("Calling private futex_wait on futex: %p\n", futex);
	if (pthread_create(&waiter, NULL, waiterfn, (void *) &flags))
		ksft_exit_fail_msg("pthread_create failed\n");

	usleep(WAKE_WAIT_US);

	ksft_print_dbg_msg("Calling private futex_wake on futex: %p\n", futex);
	res = futex_wake(futex, 1, FUTEX_PRIVATE_FLAG);
	if (res != 1) {
		ksft_test_result_fail("futex_wake private returned: %d %s\n",
				      errno, strerror(errno));
	} else {
		ksft_test_result_pass("futex_wake private succeeds\n");
	}
}

TEST(anon_page)
{
	u_int32_t *shared_data;
	pthread_t waiter;
	int res, shm_id;

	/* Testing an anon page shared memory */
	shm_id = shmget(IPC_PRIVATE, 4096, IPC_CREAT | 0666);
	if (shm_id < 0) {
		if (errno == ENOSYS)
			ksft_exit_skip("shmget syscall not supported\n");
		perror("shmget");
		exit(1);
	}

	shared_data = shmat(shm_id, NULL, 0);

	*shared_data = 0;
	futex = shared_data;

	ksft_print_dbg_msg("Calling shared (page anon) futex_wait on futex: %p\n", futex);
	if (pthread_create(&waiter, NULL, waiterfn, NULL))
		ksft_exit_fail_msg("pthread_create failed\n");

	usleep(WAKE_WAIT_US);

Annotation

Implementation Notes