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;
27static pthread_barrier_t barrier;
28
29void usage(char *prog)
30{
31 printf("Usage: %s\n", prog);
32 printf(" -c Use color\n");
33 printf(" -h Display this help message\n");
34 printf(" -t N Timeout in nanoseconds (default: 100,000)\n");
35 printf(" -v L Verbosity level: %d=QUIET %d=CRITICAL %d=INFO\n",
36 VQUIET, VCRITICAL, VINFO);
37}
38
39/*
40 * Get a PI lock and hold it forever, so the main thread lock_pi will block
41 * and we can test the timeout
42 */
43void *get_pi_lock(void *arg)
44{
45 int ret;
46 volatile futex_t lock = 0;
47
48 ret = futex_lock_pi(&futex_pi, NULL, 0, 0);
49 if (ret != 0)
50 error("futex_lock_pi failed\n", ret);
51
52 pthread_barrier_wait(&barrier);
53
54 /* Blocks forever */
55 ret = futex_wait(&lock, 0, NULL, 0);
56 error("futex_wait failed\n", ret);
57
58 return NULL;
59}
60
61/*
62 * Check if the function returned the expected error
63 */
64static void test_timeout(int res, int *ret, char *test_name, int err)
65{
66 if (!res || errno != err) {
67 ksft_test_result_fail("%s returned %d\n", test_name,
68 res < 0 ? errno : res);
69 *ret = RET_FAIL;
70 } else {
71 ksft_test_result_pass("%s succeeds\n", test_name);
72 }
73}
74
75/*
76 * Calculate absolute timeout and correct overflow
77 */
78static int futex_get_abs_timeout(clockid_t clockid, struct timespec *to,
79 long timeout_ns)
80{
81 if (clock_gettime(clockid, to)) {
82 error("clock_gettime failed\n", errno);
83 return errno;
84 }
85
86 to->tv_nsec += timeout_ns;
87
88 if (to->tv_nsec >= 1000000000) {
89 to->tv_sec++;
90 to->tv_nsec -= 1000000000;
91 }
92
93 return 0;
94}
95
96int main(int argc, char *argv[])
97{
98 futex_t f1 = FUTEX_INITIALIZER;
99 int res, ret = RET_PASS;
100 struct timespec to;
101 pthread_t thread;
102 int c;
103 struct futex_waitv waitv = {
104 .uaddr = (uintptr_t)&f1,
105 .val = f1,
106 .flags = FUTEX_32,
107 .__reserved = 0
108 };
109
110 while ((c = getopt(argc, argv, "cht:v:")) != -1) {
111 switch (c) {
112 case 'c':
113 log_color(1);
114 break;
115 case 'h':
116 usage(prog: basename(argv[0]));
117 exit(0);
118 case 't':
119 timeout_ns = atoi(optarg);
120 break;
121 case 'v':
122 log_verbosity(atoi(optarg));
123 break;
124 default:
125 usage(prog: basename(argv[0]));
126 exit(1);
127 }
128 }
129
130 ksft_print_header();
131 ksft_set_plan(9);
132 ksft_print_msg("%s: Block on a futex and wait for timeout\n",
133 basename(argv[0]));
134 ksft_print_msg("\tArguments: timeout=%ldns\n", timeout_ns);
135
136 pthread_barrier_init(&barrier, NULL, 2);
137 pthread_create(&thread, NULL, get_pi_lock, NULL);
138
139 /* initialize relative timeout */
140 to.tv_sec = 0;
141 to.tv_nsec = timeout_ns;
142
143 res = futex_wait(&f1, f1, &to, 0);
144 test_timeout(res, ret: &ret, test_name: "futex_wait relative", err: ETIMEDOUT);
145
146 /* FUTEX_WAIT_BITSET with CLOCK_REALTIME */
147 if (futex_get_abs_timeout(CLOCK_REALTIME, &to, timeout_ns))
148 return RET_FAIL;
149 res = futex_wait_bitset(&f1, f1, &to, 1, FUTEX_CLOCK_REALTIME);
150 test_timeout(res, &ret, "futex_wait_bitset realtime", ETIMEDOUT);
151
152 /* FUTEX_WAIT_BITSET with CLOCK_MONOTONIC */
153 if (futex_get_abs_timeout(CLOCK_MONOTONIC, &to, timeout_ns))
154 return RET_FAIL;
155 res = futex_wait_bitset(&f1, f1, &to, 1, 0);
156 test_timeout(res, &ret, "futex_wait_bitset monotonic", ETIMEDOUT);
157
158 /* FUTEX_WAIT_REQUEUE_PI with CLOCK_REALTIME */
159 if (futex_get_abs_timeout(CLOCK_REALTIME, &to, timeout_ns))
160 return RET_FAIL;
161 res = futex_wait_requeue_pi(&f1, f1, &futex_pi, &to, FUTEX_CLOCK_REALTIME);
162 test_timeout(res, &ret, "futex_wait_requeue_pi realtime", ETIMEDOUT);
163
164 /* FUTEX_WAIT_REQUEUE_PI with CLOCK_MONOTONIC */
165 if (futex_get_abs_timeout(CLOCK_MONOTONIC, &to, timeout_ns))
166 return RET_FAIL;
167 res = futex_wait_requeue_pi(&f1, f1, &futex_pi, &to, 0);
168 test_timeout(res, &ret, "futex_wait_requeue_pi monotonic", ETIMEDOUT);
169
170 /* Wait until the other thread calls futex_lock_pi() */
171 pthread_barrier_wait(&barrier);
172 pthread_barrier_destroy(&barrier);
173 /*
174 * FUTEX_LOCK_PI with CLOCK_REALTIME
175 * Due to historical reasons, FUTEX_LOCK_PI supports only realtime
176 * clock, but requires the caller to not set CLOCK_REALTIME flag.
177 *
178 * If you call FUTEX_LOCK_PI with a monotonic clock, it'll be
179 * interpreted as a realtime clock, and (unless you mess your machine's
180 * time or your time machine) the monotonic clock value is always
181 * smaller than realtime and the syscall will timeout immediately.
182 */
183 if (futex_get_abs_timeout(CLOCK_REALTIME, &to, timeout_ns))
184 return RET_FAIL;
185 res = futex_lock_pi(&futex_pi, &to, 0, 0);
186 test_timeout(res, &ret, "futex_lock_pi realtime", ETIMEDOUT);
187
188 /* Test operations that don't support FUTEX_CLOCK_REALTIME */
189 res = futex_lock_pi(&futex_pi, NULL, 0, FUTEX_CLOCK_REALTIME);
190 test_timeout(res, &ret, "futex_lock_pi invalid timeout flag", ENOSYS);
191
192 /* futex_waitv with CLOCK_MONOTONIC */
193 if (futex_get_abs_timeout(CLOCK_MONOTONIC, &to, timeout_ns))
194 return RET_FAIL;
195 res = futex_waitv(&waitv, 1, 0, &to, CLOCK_MONOTONIC);
196 test_timeout(res, &ret, "futex_waitv monotonic", ETIMEDOUT);
197
198 /* futex_waitv with CLOCK_REALTIME */
199 if (futex_get_abs_timeout(CLOCK_REALTIME, &to, timeout_ns))
200 return RET_FAIL;
201 res = futex_waitv(&waitv, 1, 0, &to, CLOCK_REALTIME);
202 test_timeout(res, &ret, "futex_waitv realtime", ETIMEDOUT);
203
204 ksft_print_cnts();
205 return ret;
206}
207

source code of linux/tools/testing/selftests/futex/functional/futex_wait_timeout.c