1  /* Test that setuid, pthread_create, thread exit do not deadlock (bug 28361).
       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 <support/check.h>
      20  #include <support/xthread.h>
      21  #include <unistd.h>
      22  
      23  /* How many threads to launch during each iteration.  */
      24  enum { threads = 4 };
      25  
      26  /* How many iterations to perform.  This value seems to reproduce
      27     bug 28361 in a bout one in three runs.  */
      28  enum { iterations = 5000 };
      29  
      30  /* Cache of the real user ID used by setuid_thread.  */
      31  static uid_t uid;
      32  
      33  /* Start routine for the threads.  */
      34  static void *
      35  setuid_thread (void *closure)
      36  {
      37    TEST_COMPARE (setuid (uid), 0);
      38    return NULL;
      39  }
      40  
      41  static int
      42  do_test (void)
      43  {
      44    /* The setxid machinery is still invoked even if the UID is
      45       unchanged.  (The kernel might reset other credentials as part of
      46       the system call.)  */
      47    uid = getuid ();
      48  
      49    for (int i = 0; i < iterations; ++i)
      50      {
      51        pthread_t thread_ids[threads];
      52        for (int j = 0; j < threads; ++j)
      53          thread_ids[j] = xpthread_create (NULL, setuid_thread, NULL);
      54        for (int j = 0; j < threads; ++j)
      55          xpthread_join (thread_ids[j]);
      56      }
      57  
      58    return 0;
      59  }
      60  
      61  #include <support/test-driver.c>