glibc/elf/tst-next-ver.c
Fangrui Song efa7936e4c dlsym: Make RTLD_NEXT prefer default version definition [BZ #14932]
When the first object providing foo defines both foo@v1 and foo@@v2,
dlsym(RTLD_NEXT, "foo") returns foo@v1 while dlsym(RTLD_DEFAULT, "foo")
returns foo@@v2.  The issue is that RTLD_DEFAULT uses the
DL_LOOKUP_RETURN_NEWEST flag while RTLD_NEXT doesn't.  Fix the RTLD_NEXT
branch to use DL_LOOKUP_RETURN_NEWEST.

Note: the new behavior matches FreeBSD rtld.  Future sanitizers will not
need to add versioned interceptors like https://reviews.llvm.org/D96348

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2022-05-27 12:34:49 -07:00

47 lines
1.4 KiB
C

/* Test RTLD_DEFAULT/RTLD_NEXT when the definition has multiple versions.
Copyright (C) 2018-2022 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 <stdio.h>
#include "testobj.h"
static int
do_test (void)
{
/* Resolve to foo@@v3 in nextmod3.so, instead of
foo@v1 or foo@v2. */
int (*fp) (int) = dlsym (RTLD_DEFAULT, "foo");
int res = fp (0);
printf ("preload (0) = %d, %s\n", res, res == 3 ? "ok" : "wrong");
if (res != 3)
return 1;
/* Resolve to foo@@v3 in nextmod3.so, instead of
foo@v1 or foo@v2. */
fp = dlsym (RTLD_NEXT, "foo");
res = fp (0);
printf ("preload (0) = %d, %s\n", res, res == 3 ? "ok" : "wrong");
if (res != 3)
return 1;
return 0;
}
#include <support/test-driver.c>