bionic/libc/unistd/sbrk.c
2009-03-03 19:28:35 -08:00

61 lines
2.0 KiB
C

/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <unistd.h>
#include <errno.h>
#define SBRK_ALIGN 32
/* shared with brk() implementation */
char* __bionic_brk;
void *sbrk(ptrdiff_t increment)
{
char* start;
char* end;
char* new_brk;
if ( !__bionic_brk)
__bionic_brk = __brk((void*)0);
start = (char*)(((long)__bionic_brk + SBRK_ALIGN-1) & ~(SBRK_ALIGN-1));
end = start + increment;
new_brk = __brk(end);
if (new_brk == (void*)-1)
return new_brk;
else if (new_brk < end)
{
errno = ENOMEM;
return (void*)-1;
}
__bionic_brk = new_brk;
return start;
}