1/* Wait until all threads except the current thread has exited.
2 Copyright (C) 2021-2023 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <dirent.h>
20#include <errno.h>
21#include <string.h>
22#include <support/check.h>
23#include <support/support.h>
24#include <unistd.h>
25
26void
27support_wait_for_thread_exit (void)
28{
29#ifdef __linux__
30 DIR *proc_self_task = opendir ("/proc/self/task");
31 TEST_VERIFY_EXIT (proc_self_task != NULL);
32
33 while (true)
34 {
35 errno = 0;
36 struct dirent *e = readdir (proc_self_task);
37 if (e == NULL && errno != 0)
38 FAIL_EXIT1 ("readdir: %m");
39 if (e == NULL)
40 {
41 /* Only the main thread remains. Testing may continue. */
42 closedir (proc_self_task);
43 return;
44 }
45
46 /* In some kernels, "0" entries denote a thread that has just
47 exited. */
48 if (strcmp (e->d_name, ".") == 0 || strcmp (e->d_name, "..") == 0
49 || strcmp (e->d_name, "0") == 0)
50 continue;
51
52 int task_tid = atoi (e->d_name);
53 if (task_tid <= 0)
54 FAIL_EXIT1 ("Invalid /proc/self/task entry: %s", e->d_name);
55
56 if (task_tid == gettid ())
57 /* The current thread. Keep scanning for other
58 threads. */
59 continue;
60
61 /* task_tid does not refer to this thread here, i.e., there is
62 another running thread. */
63
64 /* Small timeout to give the thread a chance to exit. */
65 usleep (50 * 1000);
66
67 /* Start scanning the directory from the start. */
68 rewinddir (proc_self_task);
69 }
70#else
71 /* Use a large timeout because we cannot verify that the thread has
72 exited. */
73 usleep (5 * 1000 * 1000);
74#endif
75}
76