glibc/elf/tst-getauxval-static.c
Florian Weimer 78b31cc834 elf: Partially initialize ld.so after static dlopen (bug 20802)
After static dlopen, a copy of ld.so is loaded into the inner
namespace, but that copy is not initialized at all.  Some
architectures run into serious problems as result, which is why the
_dl_var_init mechanism was invented.  With libpthread moving into
libc and parts into ld.so, more architectures impacted, so it makes
sense to switch to a generic mechanism which performs the partial
initialization.

As a result, getauxval now works after static dlopen (bug 20802).

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-05-17 10:06:57 +02:00

67 lines
2.1 KiB
C

/* Test getauxval from a dynamic library after static dlopen.
Copyright (C) 2021 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <dlfcn.h>
#include <errno.h>
#include <stdio.h>
#include <support/check.h>
#include <support/xdlfcn.h>
#include <sys/auxv.h>
unsigned long getauxval_wrapper (unsigned long type, int *errnop);
static int
do_test (void)
{
unsigned long outer_random = getauxval (AT_RANDOM);
if (outer_random == 0)
FAIL_UNSUPPORTED ("getauxval does not support AT_RANDOM");
unsigned long missing_auxv_type;
for (missing_auxv_type = AT_RANDOM + 1; ; ++missing_auxv_type)
{
errno = 0;
if (getauxval (missing_auxv_type) == 0 && errno != 0)
{
TEST_COMPARE (errno, ENOENT);
break;
}
}
printf ("info: first missing type: %lu\n", missing_auxv_type);
void *handle = xdlopen ("tst-auxvalmod.so", RTLD_LAZY);
void *ptr = xdlsym (handle, "getauxval_wrapper");
__typeof__ (getauxval_wrapper) *wrapper = ptr;
int inner_errno = 0;
unsigned long inner_random = wrapper (AT_RANDOM, &inner_errno);
TEST_COMPARE (outer_random, inner_random);
inner_errno = 0;
TEST_COMPARE (wrapper (missing_auxv_type, &inner_errno), 0);
TEST_COMPARE (inner_errno, ENOENT);
TEST_COMPARE (getauxval (AT_HWCAP), wrapper (AT_HWCAP, &inner_errno));
TEST_COMPARE (getauxval (AT_HWCAP2), wrapper (AT_HWCAP2, &inner_errno));
xdlclose (handle);
return 0;
}
#include <support/test-driver.c>