elf/tst-single_threaded-static-dlopen.c

   1 /* Test support for single-thread optimizations.  No threads, static dlopen.
   2    Copyright (C) 2020-2023 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 /* In a static dlopen scenario, the single-threaded optimization is
  20    not possible because their is no globally shared dynamic linker
  21    across all namespaces.  */
  22
  23 #include <stddef.h>
  24 #include <support/check.h>
  25 #include <support/xdlfcn.h>
  26 #include <sys/single_threaded.h>
  27
  28 static int
  29 do_test (void)
  30 {
  31   TEST_VERIFY (__libc_single_threaded);
  32
  33   /* Defined in tst-single-threaded-mod1.o.  */
  34   extern _Bool single_threaded_1 (void);
  35   TEST_VERIFY (single_threaded_1 ());
  36
  37   /* A failed dlopen does not change the multi-threaded status.  */
  38   TEST_VERIFY (dlopen ("tst-single_threaded-does-not-exist.so", RTLD_LAZY)
  39                == NULL);
  40   TEST_VERIFY (__libc_single_threaded);
  41   TEST_VERIFY (single_threaded_1 ());
  42
  43   /* And neither does a successful dlopen for outer (static) libc.  */
  44   void *handle_mod2 = xdlopen ("tst-single_threaded-mod2.so", RTLD_LAZY);
  45   _Bool (*single_threaded_2) (void)
  46     = xdlsym (handle_mod2, "single_threaded_2");
  47   TEST_VERIFY (__libc_single_threaded);
  48   TEST_VERIFY (single_threaded_1 ());
  49   /* The inner libc always assumes multi-threaded use.  */
  50   TEST_VERIFY (!single_threaded_2 ());
  51
  52   xdlclose (handle_mod2);
  53
  54   return 0;
  55 }
  56
  57 #include <support/test-driver.c>