sysdeps/pthread/tst-atfork3.c

   1 /* Check if pthread_atfork handler can call dlclose (BZ#24595).
   2    Copyright (C) 2022-2023 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    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <stdio.h>
  20 #include <pthread.h>
  21 #include <unistd.h>
  22 #include <stdlib.h>
  23 #include <stdbool.h>
  24
  25 #include <support/check.h>
  26 #include <support/xthread.h>
  27 #include <support/capture_subprocess.h>
  28 #include <support/xdlfcn.h>
  29
  30 /* Check if pthread_atfork handlers do not deadlock when calling a function
  31    that might alter the internal fork handle list, such as dlclose.
  32
  33    The test registers a callback set with pthread_atfork(), dlopen() a shared
  34    library (nptl/tst-atfork3mod.c), calls an exported symbol from the library
  35    (which in turn also registers atfork handlers), and calls fork to trigger
  36    the callbacks.  */
  37
  38 static void *handler;
  39 static bool run_dlclose_prepare;
  40 static bool run_dlclose_parent;
  41 static bool run_dlclose_child;
  42
  43 static void
  44 prepare (void)
  45 {
  46   if (run_dlclose_prepare)
  47     xdlclose (handler);
  48 }
  49
  50 static void
  51 parent (void)
  52 {
  53   if (run_dlclose_parent)
  54     xdlclose (handler);
  55 }
  56
  57 static void
  58 child (void)
  59 {
  60   if (run_dlclose_child)
  61     xdlclose (handler);
  62 }
  63
  64 static void
  65 proc_func (void *closure)
  66 {
  67 }
  68
  69 static void
  70 do_test_generic (bool dlclose_prepare, bool dlclose_parent, bool dlclose_child)
  71 {
  72   run_dlclose_prepare = dlclose_prepare;
  73   run_dlclose_parent = dlclose_parent;
  74   run_dlclose_child = dlclose_child;
  75
  76   handler = xdlopen ("tst-atfork3mod.so", RTLD_NOW);
  77
  78   int (*atfork3mod_func)(void);
  79   atfork3mod_func = xdlsym (handler, "atfork3mod_func");
  80
  81   atfork3mod_func ();
  82
  83   struct support_capture_subprocess proc
  84     = support_capture_subprocess (proc_func, NULL);
  85   support_capture_subprocess_check (&proc, "tst-atfork3", 0, sc_allow_none);
  86
  87   handler = atfork3mod_func = NULL;
  88
  89   support_capture_subprocess_free (&proc);
  90 }
  91
  92 static void *
  93 thread_func (void *closure)
  94 {
  95   return NULL;
  96 }
  97
  98 static int
  99 do_test (void)
 100 {
 101   {
 102     /* Make the process acts as multithread.  */
 103     pthread_attr_t attr;
 104     xpthread_attr_init (&attr);
 105     xpthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
 106     xpthread_create (&attr, thread_func, NULL);
 107   }
 108
 109   TEST_COMPARE (pthread_atfork (prepare, parent, child), 0);
 110
 111   do_test_generic (true  /* prepare */, false /* parent */, false /* child */);
 112   do_test_generic (false /* prepare */, true  /* parent */, false /* child */);
 113   do_test_generic (false /* prepare */, false /* parent */, true  /* child */);
 114
 115   return 0;
 116 }
 117
 118 #include <support/test-driver.c>