sysdeps/unix/sysv/linux/tst-gettid.c

   1 /* Smoke test for the gettid system call.
   2    Copyright (C) 2019-2024 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
  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 *
  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
  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
  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>