1  /* Test dlopen of modules with initial-exec TLS after dlmopen.
       2     Copyright (C) 2016-2023 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  /* This test tries to check that surplus static TLS is not used up for
      20     dynamic TLS optimizations and 4*144 = 576 bytes of static TLS is
      21     still available for dlopening modules with initial-exec TLS after 3
      22     new dlmopen namespaces are created.  It depends on rtld.nns=4 and
      23     rtld.optional_static_tls=512 tunable settings.  */
      24  
      25  #include <errno.h>
      26  #include <pthread.h>
      27  #include <stdio.h>
      28  #include <stdlib.h>
      29  #include <string.h>
      30  
      31  static int do_test (void);
      32  #include <support/xthread.h>
      33  #include <support/xdlfcn.h>
      34  #include <support/check.h>
      35  #include <support/test-driver.c>
      36  
      37  /* Have some big TLS in the main exe: should not use surplus TLS.  */
      38  __thread char maintls[1000];
      39  
      40  static pthread_barrier_t barrier;
      41  
      42  /* Forces multi-threaded behaviour.  */
      43  static void *
      44  blocked_thread_func (void *closure)
      45  {
      46    xpthread_barrier_wait (&barrier);
      47    /* TLS load and access tests run here in the main thread.  */
      48    xpthread_barrier_wait (&barrier);
      49    return NULL;
      50  }
      51  
      52  static void *
      53  load_and_access (Lmid_t lmid, const char *mod, const char *func)
      54  {
      55    /* Load module with TLS.  */
      56    void *p = xdlmopen (lmid, mod, RTLD_NOW);
      57    /* Access the TLS variable to ensure it is allocated.  */
      58    void (*f) (void) = (void (*) (void))xdlsym (p, func);
      59    f ();
      60    return p;
      61  }
      62  
      63  static int
      64  do_test (void)
      65  {
      66    void *mods[5];
      67  
      68    {
      69      int ret = pthread_barrier_init (&barrier, NULL, 2);
      70      if (ret != 0)
      71        {
      72          errno = ret;
      73          printf ("error: pthread_barrier_init: %m\n");
      74          exit (1);
      75        }
      76    }
      77  
      78    pthread_t blocked_thread = xpthread_create (NULL, blocked_thread_func, NULL);
      79    xpthread_barrier_wait (&barrier);
      80  
      81    printf ("maintls[%zu]:\t %p .. %p\n",
      82  	   sizeof maintls, maintls, maintls + sizeof maintls);
      83    memset (maintls, 1, sizeof maintls);
      84  
      85    /* Load modules with dynamic TLS (use surplus static TLS for libc
      86       in new namespaces and may be for TLS optimizations too).  */
      87    mods[0] = load_and_access (LM_ID_BASE, "tst-tls-ie-mod0.so", "access0");
      88    mods[1] = load_and_access (LM_ID_NEWLM, "tst-tls-ie-mod1.so", "access1");
      89    mods[2] = load_and_access (LM_ID_NEWLM, "tst-tls-ie-mod2.so", "access2");
      90    mods[3] = load_and_access (LM_ID_NEWLM, "tst-tls-ie-mod3.so", "access3");
      91    /* Load modules with initial-exec TLS (can only use surplus static TLS).  */
      92    mods[4] = load_and_access (LM_ID_BASE, "tst-tls-ie-mod6.so", "access6");
      93  
      94    /* Here 576 bytes + 3 * libc use of surplus static TLS is in use so less
      95       than 1024 bytes are available (exact number depends on TLS optimizations
      96       and the libc TLS use).  */
      97    printf ("The next dlmopen should fail...\n");
      98    void *p = dlmopen (LM_ID_BASE, "tst-tls-ie-mod4.so", RTLD_NOW);
      99    if (p != NULL)
     100      FAIL_EXIT1 ("error: expected dlmopen to fail because there is "
     101  		"not enough surplus static TLS.\n");
     102    printf ("...OK failed with: %s.\n", dlerror ());
     103  
     104    xpthread_barrier_wait (&barrier);
     105    xpthread_join (blocked_thread);
     106  
     107    /* Close the modules.  */
     108    for (int i = 0; i < 5; ++i)
     109      xdlclose (mods[i]);
     110  
     111    return 0;
     112  }