glibc/sysdeps/mach/hurd/sbrk.c

/* Copyright (C) 1991-2019 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 <errno.h>
#include <hurd.h>
#include <unistd.h>

/* Extend the process's data space by INCREMENT.
   If INCREMENT is negative, shrink data space by - INCREMENT.
   Return the address of the start of the new data space, or -1 for errors.  */
void *
__sbrk (intptr_t increment)
{
  void *result;

  HURD_CRITICAL_BEGIN;
  __mutex_lock (&_hurd_brk_lock);
  result = (void *) _hurd_brk;
  if (increment != 0 && _hurd_set_brk (_hurd_brk + increment) < 0)
    result = (void *) -1;
  __mutex_unlock (&_hurd_brk_lock);
  HURD_CRITICAL_END;

  return result;
}
libc_hidden_def (__sbrk)
weak_alias (__sbrk, sbrk)