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/* Test TLS allocation with an interposed malloc.
Copyright (C) 2016 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
<http://www.gnu.org/licenses/>. */
/* Reuse the test. */
#include "tst-tls3.c"
#include <sys/mman.h>
/* Interpose a minimal malloc implementation. This implementation
deliberately interposes just a restricted set of symbols, to detect
if the TLS code bypasses the interposed malloc. */
/* Lock to guard malloc internals. */
static pthread_mutex_t malloc_lock = PTHREAD_MUTEX_INITIALIZER;
/* Information about an allocation chunk. */
struct malloc_chunk
{
/* Start of the allocation. */
void *start;
/* Size of the allocation. */
size_t size;
};
enum { malloc_chunk_count = 1000 };
static struct malloc_chunk chunks[malloc_chunk_count];
/* Lock the malloc lock. */
static void
xlock (void)
{
int ret = pthread_mutex_lock (&malloc_lock);
if (ret != 0)
{
errno = ret;
printf ("error: pthread_mutex_lock: %m\n");
_exit (1);
}
}
/* Unlock the malloc lock. */
static void
xunlock (void)
{
int ret = pthread_mutex_unlock (&malloc_lock);
if (ret != 0)
{
errno = ret;
printf ("error: pthread_mutex_unlock: %m\n");
_exit (1);
}
}
/* Internal malloc without locking and registration. */
static void *
malloc_internal (size_t size)
{
void *result = mmap (NULL, size, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
if (result == MAP_FAILED)
{
printf ("error: mmap: %m\n");
_exit (1);
}
return result;
}
void *
malloc (size_t size)
{
if (size == 0)
size = 1;
xlock ();
void *result = malloc_internal (size);
for (int i = 0; i < malloc_chunk_count; ++i)
if (chunks[i].start == NULL)
{
chunks[i].start = result;
chunks[i].size = size;
xunlock ();
return result;
}
xunlock ();
printf ("error: no place to store chunk pointer\n");
_exit (1);
}
void *
calloc (size_t a, size_t b)
{
if (b != 0 && a > SIZE_MAX / b)
return NULL;
/* malloc uses mmap, which provides zeroed memory. */
return malloc (a * b);
}
static void
xunmap (void *ptr, size_t size)
{
int ret = munmap (ptr, size);
if (ret < 0)
{
printf ("error: munmap (%p, %zu) failed: %m\n", ptr, size);
_exit (1);
}
}
void
free (void *ptr)
{
if (ptr == NULL)
return;
xlock ();
for (int i = 0; i < malloc_chunk_count; ++i)
if (chunks[i].start == ptr)
{
xunmap (ptr, chunks[i].size);
chunks[i] = (struct malloc_chunk) {};
xunlock ();
return;
}
xunlock ();
printf ("error: tried to free non-allocated pointer %p\n", ptr);
_exit (1);
}
void *
realloc (void *old, size_t size)
{
if (old != NULL)
{
xlock ();
for (int i = 0; i < malloc_chunk_count; ++i)
if (chunks[i].start == old)
{
size_t old_size = chunks[i].size;
void *result;
if (old_size < size)
{
result = malloc_internal (size);
/* Reuse the slot for the new allocation. */
memcpy (result, old, old_size);
xunmap (old, old_size);
chunks[i].start = result;
chunks[i].size = size;
}
else
/* Old size is not smaller, so reuse the old
allocation. */
result = old;
xunlock ();
return result;
}
xunlock ();
printf ("error: tried to realloc non-allocated pointer %p\n", old);
_exit (1);
}
else
return malloc (size);
}
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