1/* Smoke test for the gettid system call.
2 Copyright (C) 2019-2022 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 <support/check.h>
20#include <support/namespace.h>
21#include <support/xthread.h>
22#include <support/xunistd.h>
23
24/* TID of the initial (main) thread. */
25static pid_t initial_tid;
26
27/* Check that PID and TID are the same in a subprocess. */
28static void
29subprocess (void *closure)
30{
31 TEST_COMPARE (getpid (), gettid ());
32 TEST_VERIFY (gettid () != initial_tid);
33}
34
35/* Check that the TID changes in a new thread. */
36static void *
37threadfunc (void *closure)
38{
39 TEST_VERIFY (getpid () != gettid ());
40 TEST_VERIFY (gettid () != initial_tid);
41 return NULL;
42}
43
44/* Check for interactions with vfork. */
45static void
46test_vfork (void)
47{
48 pid_t proc = vfork ();
49 if (proc == 0)
50 {
51 if (getpid () != gettid ())
52 _exit (1);
53 if (gettid () == initial_tid)
54 _exit (2);
55 _exit (0);
56 }
57 int status;
58 xwaitpid (proc, status: &status, flags: 0);
59 TEST_COMPARE (status, 0);
60}
61
62static int
63do_test (void)
64{
65 initial_tid = gettid ();
66
67 /* The main thread has the same TID as the PID. */
68 TEST_COMPARE (getpid (), gettid ());
69
70 test_vfork ();
71
72 support_isolate_in_subprocess (callback: subprocess, NULL);
73
74 xpthread_join (thr: xpthread_create (NULL, thread_func: threadfunc, NULL));
75
76 return 0;
77}
78
79#include <support/test-driver.c>
80

source code of glibc/sysdeps/unix/sysv/linux/tst-gettid.c