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/* brk system call for Linux/i386.
Copyright (C) 1995, 1996, 2000 Free Software Foundation, Inc.
Copyright (c) 2015 mirabilos <tg@mirbsd.org>
This file is part of uclibc-ng, derived from 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 <unistd.h>
#include <sys/syscall.h>
/* This must be initialized data because commons can't have aliases. */
void *__curbrk attribute_hidden = 0;
int brk(void *addr)
{
void *newbrk;
/*
* EBC is used in PIC code, we need to save/restore it manually.
* Unfortunately, GCC won't do that for us even if we use con-
* straints, and we cannot push it either as ESP clobbers are
* silently ignored, but EDX is preserved, so it's scratch space.
*/
__asm__("xchgl %%edx,%%ebx"
"\n int $0x80"
"\n xchgl %%edx,%%ebx"
: "=a" (newbrk)
: "0" (__NR_brk), "d" (addr)
: "cc"
);
__curbrk = newbrk;
if (newbrk < addr) {
__set_errno(ENOMEM);
return -1;
}
return 0;
}
libc_hidden_def(brk)
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