1 /* Smoke test for the gettid system call.
2    Copyright (C) 2019-2021 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.  */
25 static pid_t initial_tid;
26 
27 /* Check that PID and TID are the same in a subprocess.  */
28 static void
subprocess(void * closure)29 subprocess (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.  */
36 static void *
threadfunc(void * closure)37 threadfunc (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.  */
45 static void
test_vfork(void)46 test_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, 0);
59   TEST_COMPARE (status, 0);
60 }
61 
62 static int
do_test(void)63 do_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 (subprocess, NULL);
73 
74   xpthread_join (xpthread_create (NULL, threadfunc, NULL));
75 
76   return 0;
77 }
78 
79 #include <support/test-driver.c>
80