sysdeps/pthread/tst-pthread-setuid-loop.c

   1 /* Test that setuid, pthread_create, thread exit do not deadlock (bug 28361).
   2    Copyright (C) 2021-2022 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/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>