1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (c) 2018 Google, Inc.
4 *
5 * tgkill() delivers a signal to a specific thread. Test this by installing
6 * a SIGUSR1 handler which records the current pthread ID. Start a number
7 * of threads in parallel, then one-by-one call tgkill(..., tid, SIGUSR1)
8 * and check that the expected pthread ID was recorded.
9 */
10
11 #include <pthread.h>
12 #include <stdlib.h>
13
14 #include "tst_safe_pthread.h"
15 #include "tst_test.h"
16 #include "tgkill.h"
17
18 struct thread_state {
19 pthread_t thread;
20 pid_t tid;
21 };
22
23 static char *str_threads;
24 static int n_threads = 10;
25 static struct thread_state *threads;
26
27 static pthread_t sigusr1_thread;
28
sigusr1_handler(int signum)29 static void sigusr1_handler(int signum __attribute__((unused)))
30 {
31 sigusr1_thread = pthread_self();
32 }
33
thread_func(void * arg)34 static void *thread_func(void *arg)
35 {
36 struct thread_state *thread = arg;
37
38 /**
39 * There is no standard way to map pthread -> tid, so we will have the
40 * child stash its own tid then notify the parent that the stashed tid
41 * is available.
42 */
43 thread->tid = sys_gettid();
44
45 TST_CHECKPOINT_WAKE(0);
46
47 TST_CHECKPOINT_WAIT(1);
48
49 return arg;
50 }
51
start_thread(struct thread_state * thread)52 static void start_thread(struct thread_state *thread)
53 {
54 SAFE_PTHREAD_CREATE(&thread->thread, NULL, thread_func, thread);
55
56 TST_CHECKPOINT_WAIT(0);
57 }
58
stop_threads(void)59 static void stop_threads(void)
60 {
61 int i;
62
63 TST_CHECKPOINT_WAKE2(1, n_threads);
64
65 for (i = 0; i < n_threads; i++) {
66 if (threads[i].tid == -1)
67 continue;
68
69 SAFE_PTHREAD_JOIN(threads[i].thread, NULL);
70 threads[i].tid = -1;
71 }
72
73 if (threads)
74 free(threads);
75 }
76
run(void)77 static void run(void)
78 {
79 int i;
80
81 for (i = 0; i < n_threads; i++) {
82 sigusr1_thread = pthread_self();
83
84 TEST(sys_tgkill(getpid(), threads[i].tid, SIGUSR1));
85 if (TST_RET) {
86 tst_res(TFAIL | TTERRNO, "tgkill() failed");
87 return;
88 }
89
90 while (pthread_equal(sigusr1_thread, pthread_self()))
91 usleep(1000);
92
93 if (!pthread_equal(sigusr1_thread, threads[i].thread)) {
94 tst_res(TFAIL, "SIGUSR1 delivered to wrong thread");
95 return;
96 }
97 }
98
99 tst_res(TPASS, "SIGUSR1 delivered to correct threads");
100 }
101
setup(void)102 static void setup(void)
103 {
104 int i;
105
106 if (tst_parse_int(str_threads, &n_threads, 1, INT_MAX))
107 tst_brk(TBROK, "Invalid number of threads '%s'", str_threads);
108
109 threads = SAFE_MALLOC(sizeof(*threads) * n_threads);
110
111 struct sigaction sigusr1 = {
112 .sa_handler = sigusr1_handler,
113 };
114 SAFE_SIGACTION(SIGUSR1, &sigusr1, NULL);
115
116 for (i = 0; i < n_threads; i++)
117 threads[i].tid = -1;
118
119 for (i = 0; i < n_threads; i++)
120 start_thread(&threads[i]);
121 }
122
123 static struct tst_option options[] = {
124 {"t:", &str_threads, "-t Number of threads (default 10)"},
125 {NULL, NULL, NULL},
126 };
127
128 static struct tst_test test = {
129 .options = options,
130 .needs_checkpoints = 1,
131 .setup = setup,
132 .test_all = run,
133 .cleanup = stop_threads,
134 };
135