1// SPDX-License-Identifier: GPL-2.0-or-later
  2/******************************************************************************
  3 *
  4 *   Copyright © International Business Machines  Corp., 2009
  5 *
  6 * DESCRIPTION
  7 *      Block on a futex and wait for timeout.
  8 *
  9 * AUTHOR
 10 *      Darren Hart <dvhart@linux.intel.com>
 11 *
 12 * HISTORY
 13 *      2009-Nov-6: Initial version by Darren Hart <dvhart@linux.intel.com>
 14 *      2021-Apr-26: More test cases by André Almeida <andrealmeid@collabora.com>
 15 *
 16 *****************************************************************************/
 17
 18#include <pthread.h>
 19#include "futextest.h"
 20#include "futex2test.h"
 21#include "logging.h"
 22
 23#define TEST_NAME "futex-wait-timeout"
 24
 25static long timeout_ns = 100000;	/* 100us default timeout */
 26static futex_t futex_pi;
 27
 28void usage(char *prog)
 29{
 30	printf("Usage: %s\n", prog);
 31	printf("  -c	Use color\n");
 32	printf("  -h	Display this help message\n");
 33	printf("  -t N	Timeout in nanoseconds (default: 100,000)\n");
 34	printf("  -v L	Verbosity level: %d=QUIET %d=CRITICAL %d=INFO\n",
 35	       VQUIET, VCRITICAL, VINFO);
 36}
 37
 38/*
 39 * Get a PI lock and hold it forever, so the main thread lock_pi will block
 40 * and we can test the timeout
 41 */
 42void *get_pi_lock(void *arg)
 43{
 44	int ret;
 45	volatile futex_t lock = 0;
 46
 47	ret = futex_lock_pi(&futex_pi, NULL, 0, 0);
 48	if (ret != 0)
 49		error("futex_lock_pi failed\n", ret);
 50
 51	/* Blocks forever */
 52	ret = futex_wait(&lock, 0, NULL, 0);
 53	error("futex_wait failed\n", ret);
 54
 55	return NULL;
 56}
 57
 58/*
 59 * Check if the function returned the expected error
 60 */
 61static void test_timeout(int res, int *ret, char *test_name, int err)
 62{
 63	if (!res || errno != err) {
 64		ksft_test_result_fail("%s returned %d\n", test_name,
 65				      res < 0 ? errno : res);
 66		*ret = RET_FAIL;
 67	} else {
 68		ksft_test_result_pass("%s succeeds\n", test_name);
 69	}
 70}
 71
 72/*
 73 * Calculate absolute timeout and correct overflow
 74 */
 75static int futex_get_abs_timeout(clockid_t clockid, struct timespec *to,
 76				 long timeout_ns)
 77{
 78	if (clock_gettime(clockid, to)) {
 79		error("clock_gettime failed\n", errno);
 80		return errno;
 81	}
 82
 83	to->tv_nsec += timeout_ns;
 84
 85	if (to->tv_nsec >= 1000000000) {
 86		to->tv_sec++;
 87		to->tv_nsec -= 1000000000;
 88	}
 89
 90	return 0;
 91}
 92
 93int main(int argc, char *argv[])
 94{
 95	futex_t f1 = FUTEX_INITIALIZER;
 96	int res, ret = RET_PASS;
 97	struct timespec to;
 98	pthread_t thread;
 99	int c;
100	struct futex_waitv waitv = {
101			.uaddr = (uintptr_t)&f1,
102			.val = f1,
103			.flags = FUTEX_32,
104			.__reserved = 0
105		};
106
107	while ((c = getopt(argc, argv, "cht:v:")) != -1) {
108		switch (c) {
109		case 'c':
110			log_color(1);
111			break;
112		case 'h':
113			usage(basename(argv[0]));
114			exit(0);
115		case 't':
116			timeout_ns = atoi(optarg);
117			break;
118		case 'v':
119			log_verbosity(atoi(optarg));
120			break;
121		default:
122			usage(basename(argv[0]));
123			exit(1);
124		}
125	}
126
127	ksft_print_header();
128	ksft_set_plan(9);
129	ksft_print_msg("%s: Block on a futex and wait for timeout\n",
130	       basename(argv[0]));
131	ksft_print_msg("\tArguments: timeout=%ldns\n", timeout_ns);
132
133	pthread_create(&thread, NULL, get_pi_lock, NULL);
134
135	/* initialize relative timeout */
136	to.tv_sec = 0;
137	to.tv_nsec = timeout_ns;
138
139	res = futex_wait(&f1, f1, &to, 0);
140	test_timeout(res, &ret, "futex_wait relative", ETIMEDOUT);
141
142	/* FUTEX_WAIT_BITSET with CLOCK_REALTIME */
143	if (futex_get_abs_timeout(CLOCK_REALTIME, &to, timeout_ns))
144		return RET_FAIL;
145	res = futex_wait_bitset(&f1, f1, &to, 1, FUTEX_CLOCK_REALTIME);
146	test_timeout(res, &ret, "futex_wait_bitset realtime", ETIMEDOUT);
147
148	/* FUTEX_WAIT_BITSET with CLOCK_MONOTONIC */
149	if (futex_get_abs_timeout(CLOCK_MONOTONIC, &to, timeout_ns))
150		return RET_FAIL;
151	res = futex_wait_bitset(&f1, f1, &to, 1, 0);
152	test_timeout(res, &ret, "futex_wait_bitset monotonic", ETIMEDOUT);
153
154	/* FUTEX_WAIT_REQUEUE_PI with CLOCK_REALTIME */
155	if (futex_get_abs_timeout(CLOCK_REALTIME, &to, timeout_ns))
156		return RET_FAIL;
157	res = futex_wait_requeue_pi(&f1, f1, &futex_pi, &to, FUTEX_CLOCK_REALTIME);
158	test_timeout(res, &ret, "futex_wait_requeue_pi realtime", ETIMEDOUT);
159
160	/* FUTEX_WAIT_REQUEUE_PI with CLOCK_MONOTONIC */
161	if (futex_get_abs_timeout(CLOCK_MONOTONIC, &to, timeout_ns))
162		return RET_FAIL;
163	res = futex_wait_requeue_pi(&f1, f1, &futex_pi, &to, 0);
164	test_timeout(res, &ret, "futex_wait_requeue_pi monotonic", ETIMEDOUT);
165
166	/*
167	 * FUTEX_LOCK_PI with CLOCK_REALTIME
168	 * Due to historical reasons, FUTEX_LOCK_PI supports only realtime
169	 * clock, but requires the caller to not set CLOCK_REALTIME flag.
170	 *
171	 * If you call FUTEX_LOCK_PI with a monotonic clock, it'll be
172	 * interpreted as a realtime clock, and (unless you mess your machine's
173	 * time or your time machine) the monotonic clock value is always
174	 * smaller than realtime and the syscall will timeout immediately.
175	 */
176	if (futex_get_abs_timeout(CLOCK_REALTIME, &to, timeout_ns))
177		return RET_FAIL;
178	res = futex_lock_pi(&futex_pi, &to, 0, 0);
179	test_timeout(res, &ret, "futex_lock_pi realtime", ETIMEDOUT);
180
181	/* Test operations that don't support FUTEX_CLOCK_REALTIME */
182	res = futex_lock_pi(&futex_pi, NULL, 0, FUTEX_CLOCK_REALTIME);
183	test_timeout(res, &ret, "futex_lock_pi invalid timeout flag", ENOSYS);
184
185	/* futex_waitv with CLOCK_MONOTONIC */
186	if (futex_get_abs_timeout(CLOCK_MONOTONIC, &to, timeout_ns))
187		return RET_FAIL;
188	res = futex_waitv(&waitv, 1, 0, &to, CLOCK_MONOTONIC);
189	test_timeout(res, &ret, "futex_waitv monotonic", ETIMEDOUT);
190
191	/* futex_waitv with CLOCK_REALTIME */
192	if (futex_get_abs_timeout(CLOCK_REALTIME, &to, timeout_ns))
193		return RET_FAIL;
194	res = futex_waitv(&waitv, 1, 0, &to, CLOCK_REALTIME);
195	test_timeout(res, &ret, "futex_waitv realtime", ETIMEDOUT);
196
197	ksft_print_cnts();
198	return ret;
199}