glibc/misc/sbrk.c
H.J. Lu 54e4b8f215 Mark __libc_multiple_libcs with attribute_hidden [BZ #18822]
Since __libc_multiple_libcs is defined as hidden symbol in init-first.c,
it should be always marked with attribute_hidden.

	[BZ #18822]
	* csu/libc-start.c (__libc_multiple_libcs): Removed.
	* elf/dl-open.c: Include <libc-internal.h>.
	(__libc_multiple_libcs): Removed.
	* elf/dl-sysdep.c: Include <libc-internal.h> instead of
	<hp-timing.h>.
	* include/libc-internal.h (__libc_multiple_libcs): New.
	* misc/sbrk.c: Include <libc-internal.h>.
	(__libc_multiple_libcs): Removed.
2017-08-21 05:32:39 -07:00

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C

/* Copyright (C) 1991-2017 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/>. */
#include <errno.h>
#include <stdint.h>
#include <unistd.h>
#include <libc-internal.h>
/* Defined in brk.c. */
extern void *__curbrk;
extern int __brk (void *addr);
/* Extend the process's data space by INCREMENT.
If INCREMENT is negative, shrink data space by - INCREMENT.
Return start of new space allocated, or -1 for errors. */
void *
__sbrk (intptr_t increment)
{
void *oldbrk;
/* If this is not part of the dynamic library or the library is used
via dynamic loading in a statically linked program update
__curbrk from the kernel's brk value. That way two separate
instances of __brk and __sbrk can share the heap, returning
interleaved pieces of it. */
if (__curbrk == NULL || __libc_multiple_libcs)
if (__brk (0) < 0) /* Initialize the break. */
return (void *) -1;
if (increment == 0)
return __curbrk;
oldbrk = __curbrk;
if (increment > 0
? ((uintptr_t) oldbrk + (uintptr_t) increment < (uintptr_t) oldbrk)
: ((uintptr_t) oldbrk < (uintptr_t) -increment))
{
__set_errno (ENOMEM);
return (void *) -1;
}
if (__brk (oldbrk + increment) < 0)
return (void *) -1;
return oldbrk;
}
libc_hidden_def (__sbrk)
weak_alias (__sbrk, sbrk)