glibc/sysdeps/generic/dl-dtv.h
Florian Weimer a2ff21f825 elf: Avoid using memalign for TLS allocations [BZ #17730]
Instead of a flag which indicates the pointer can be freed, dtv_t
now includes the pointer which should be freed.  Due to padding,
the size of dtv_t does not increase.

To avoid using memalign, the new allocate_dtv_entry function
allocates a sufficiently large buffer so that a sub-buffer
can be found in it which starts with an aligned pointer.  Both
the aligned and original pointers are kept, the latter for calling
free later.
2016-08-03 16:15:38 +02:00

39 lines
1.3 KiB
C

/* Generic declarations for DTV-based TLS handling in the dynamic linker.
Copyright (C) 2002-2016 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/>. */
#ifndef _DL_DTV_H
#define _DL_DTV_H
struct dtv_pointer
{
void *val; /* Pointer to data, or TLS_DTV_UNALLOCATED. */
void *to_free; /* Unaligned pointer, for deallocation. */
};
/* Type for the dtv. */
typedef union dtv
{
size_t counter;
struct dtv_pointer pointer;
} dtv_t;
/* Value used for dtv entries for which the allocation is delayed. */
#define TLS_DTV_UNALLOCATED ((void *) -1l)
#endif /* _DLT_DTV_H */