stdlib/test-dlclose-exit-race.c

   1 /* Test for exit/dlclose race (Bug 22180).
   2    Copyright (C) 2017 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    <http://www.gnu.org/licenses/>.  */
  18
  19 /* This file must be run from within a directory called "stdlib".  */
  20
  21 /* This test verifies that when dlopen in one thread races against exit
  22    in another thread, we don't call registered destructor twice.
  23
  24    Expected result:
  25      second
  26      first
  27      ... clean termination
  28 */
  29
  30 #include <stdio.h>
  31 #include <stdlib.h>
  32 #include <semaphore.h>
  33 #include <support/check.h>
  34 #include <support/xdlfcn.h>
  35 #include <support/xthread.h>
  36
  37 /* Semaphore to ensure we have a happens-before between the first function
  38    starting and exit being called.  */
  39 sem_t order1;
  40
  41 /* Semaphore to ensure we have a happens-before between the second function
  42    starting and the first function returning.  */
  43 sem_t order2;
  44
  45 void *
  46 exit_thread (void *arg)
  47 {
  48   /* Wait for the dlclose to start...  */
  49   sem_wait (&order1);
  50   /* Then try to run the exit sequence which should call all
  51      __cxa_atexit registered functions and in parallel with
  52      the executing dlclose().  */
  53   exit (0);
  54 }
  55
  56
  57 void
  58 last (void)
  59 {
  60   /* Let dlclose thread proceed.  */
  61   sem_post (&order2);
  62 }
  63
  64 int
  65 main (void)
  66 {
  67   void *dso;
  68   pthread_t thread;
  69
  70   atexit (last);
  71
  72   dso = xdlopen ("$ORIGIN/test-dlclose-exit-race-helper.so",
  73                  RTLD_NOW|RTLD_GLOBAL);
  74   thread = xpthread_create (NULL, exit_thread, NULL);
  75
  76   xdlclose (dso);
  77   xpthread_join (thread);
  78
  79   FAIL_EXIT1 ("Did not terminate via exit(0) in exit_thread() as expected.");
  80 }