glibc/elf/tst-dlmopen-twice-mod1.c
Florian Weimer 924e4f3eaa elf: Call __libc_early_init for reused namespaces (bug 29528)
libc_map is never reset to NULL, neither during dlclose nor on a
dlopen call which reuses the namespace structure.  As a result, if a
namespace is reused, its libc is not initialized properly.  The most
visible result is a crash in the <ctype.h> functions.

To prevent similar bugs on namespace reuse from surfacing,
unconditionally initialize the chosen namespace to zero using memset.

(cherry picked from commit d0e357ff45)
2022-08-30 16:31:03 +02:00

38 lines
1.3 KiB
C

/* Initialization of libc after dlmopen/dlclose/dlmopen (bug 29528). Module 1.
Copyright (C) 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 <stdio.h>
static void __attribute__ ((constructor))
init (void)
{
puts ("info: tst-dlmopen-twice-mod1.so loaded");
fflush (stdout);
}
static void __attribute__ ((destructor))
fini (void)
{
puts ("info: tst-dlmopen-twice-mod1.so about to be unloaded");
fflush (stdout);
}
/* Large allocation. The second module does not have this, so it
should load libc at a different address. */
char large_allocate[16 * 1024 * 1024];