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/* $OpenBSD: tib.c,v 1.1 2016/05/07 19:05:22 guenther Exp $ */
/*
* Copyright (c) 2016 Philip Guenther <guenther@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <tib.h>
#ifndef PIC
# include <stdlib.h> /* malloc and free */
#endif
#define ELF_ROUND(x,malign) (((x) + (malign)-1) & ~((malign)-1))
/*
* The functions here are weak so that the ld.so versions are used
* in dynamic links, whether or not libc is static
*/
void *_dl_allocate_tib(size_t _extra) __attribute__((weak));
void _dl_free_tib(void *_tib, size_t _extra) __attribute__((weak));
/*
* Allocate a TIB for passing to __tfork for a new thread. 'extra'
* is the amount of space to allocate on the side of the TIB opposite
* of the TLS data: before the TIB for variant 1 and after the TIB
* for variant 2. If non-zero, tib_thread is set to point to that area.
*/
void *
_dl_allocate_tib(size_t extra)
{
#ifdef PIC
return NULL; /* overriden by ld.so */
#else
char *base;
char *thread;
struct tib *tib;
# if TLS_VARIANT == 1
/* round up the extra size to align the tib after it */
extra = ELF_ROUND(extra, sizeof(void *));
base = malloc(extra + sizeof(struct tib) + _static_tls_size);
tib = (struct tib *)(base + extra);
thread = base;
# elif TLS_VARIANT == 2
/* round up the tib size to align the extra area after it */
base = malloc(ELF_ROUND(sizeof(struct tib), TIB_EXTRA_ALIGN) +
extra + _static_tls_size);
tib = (struct tib *)(base + _static_tls_size);
thread = (char *)tib + ELF_ROUND(sizeof(struct tib), TIB_EXTRA_ALIGN);
# endif
_static_tls_init(base);
TIB_INIT(tib, NULL, thread);
return (tib);
#endif /* !PIC */
}
void
_dl_free_tib(void *tib, size_t extra)
{
#ifndef PIC
size_t tib_offset;
# if TLS_VARIANT == 1
tib_offset = ELF_ROUND(extra, sizeof(void *));
# elif TLS_VARIANT == 2
tib_offset = _static_tls_size;
# endif
free((char *)tib - tib_offset);
#endif /* !PIC */
}
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