stdlib/tst-tls-atexit.c

   1 /* Verify that DSO is unloaded only if its TLS objects are destroyed.
   2    Copyright (C) 2013-2015 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 test dynamically loads a DSO and spawns a thread that subsequently
  20    calls into the DSO to register a destructor for an object in the DSO and
  21    then calls dlclose on the handle for the DSO.  When the thread exits, the
  22    DSO should not be unloaded or else the destructor called during thread exit
  23    will crash.  Further in the main thread, the DSO is opened and closed again,
  24    at which point the DSO should be unloaded.  */
  25
  26 #include <dlfcn.h>
  27 #include <pthread.h>
  28 #include <stdio.h>
  29 #include <unistd.h>
  30 #include <string.h>
  31 #include <errno.h>
  32 #include <link.h>
  33
  34 #define DSO_NAME "$ORIGIN/tst-tls-atexit-lib.so"
  35
  36 /* Walk through the map in the _r_debug structure to see if our lib is still
  37    loaded.  */
  38 static bool
  39 is_loaded (void)
  40 {
  41   struct link_map *lm = (struct link_map *) _r_debug.r_map;
  42
  43   for (; lm; lm = lm->l_next)
  44     if (lm->l_type == lt_loaded && lm->l_name
  45         && strcmp (basename (DSO_NAME), basename (lm->l_name)) == 0)
  46           return true;
  47   return false;
  48 }
  49
  50 /* Accept a valid handle returned by DLOPEN, load the reg_dtor symbol to
  51    register a destructor and then call dlclose on the handle.  The dlclose
  52    should not unload the DSO since the destructor has not been called yet.  */
  53 static void *
  54 reg_dtor_and_close (void *h)
  55 {
  56   void (*reg_dtor) (void) = (void (*) (void)) dlsym (h, "reg_dtor");
  57
  58   if (reg_dtor == NULL)
  59     {
  60       printf ("Unable to find symbol: %s\n", dlerror ());
  61       return (void *) (uintptr_t) 1;
  62     }
  63
  64   reg_dtor ();
  65
  66   dlclose (h);
  67
  68   return NULL;
  69 }
  70
  71 static int
  72 spawn_thread (void *h)
  73 {
  74   pthread_t t;
  75   int ret;
  76   void *thr_ret;
  77
  78   if ((ret = pthread_create (&t, NULL, reg_dtor_and_close, h)) != 0)
  79     {
  80       printf ("pthread_create failed: %s\n", strerror (ret));
  81       return 1;
  82     }
  83
  84   if ((ret = pthread_join (t, &thr_ret)) != 0)
  85     {
  86       printf ("pthread_join failed: %s\n", strerror (ret));
  87       return 1;
  88     }
  89
  90   if (thr_ret != NULL)
  91     return 1;
  92
  93   return 0;
  94 }
  95
  96 static int
  97 do_test (void)
  98 {
  99   /* Load the DSO.  */
 100   void *h1 = dlopen (DSO_NAME, RTLD_LAZY);
 101   if (h1 == NULL)
 102     {
 103       printf ("h1: Unable to load DSO: %s\n", dlerror ());
 104       return 1;
 105     }
 106
 107   if (spawn_thread (h1) != 0)
 108     return 1;
 109
 110   /* Now this should unload the DSO.  FIXME: This is a bug, calling dlclose
 111      like this is actually wrong, but it works because cxa_thread_atexit_impl
 112      has a bug which results in dlclose allowing this to work.  */
 113   dlclose (h1);
 114
 115   /* Check link maps to ensure that the DSO has unloaded.  */
 116   if (is_loaded ())
 117     return 1;
 118
 119   return 0;
 120 }
 121
 122 #define TEST_FUNCTION do_test ()
 123 #include "../test-skeleton.c"