1 /* brk system call for Linux/x86_64.
2    Copyright (C) 1995, 1996, 2000 Free Software Foundation, Inc.
3    This file is part of the GNU C Library.
4 
5    The GNU C Library is free software; you can redistribute it and/or
6    modify it under the terms of the GNU Lesser General Public
7    License as published by the Free Software Foundation; either
8    version 2.1 of the License, or (at your option) any later version.
9 
10    The GNU C Library is distributed in the hope that it will be useful,
11    but WITHOUT ANY WARRANTY; without even the implied warranty of
12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13    Lesser General Public License for more details.
14 
15    You should have received a copy of the GNU Lesser General Public
16    License along with the GNU C Library; if not, see
17    <http://www.gnu.org/licenses/>.  */
18 
19 #include <errno.h>
20 #include <unistd.h>
21 #include <sys/syscall.h>
22 
23 /* This must be initialized data because commons can't have aliases.  */
24 void *__curbrk attribute_hidden = 0;
25 
brk(void * addr)26 int brk(void *addr)
27 {
28 	void *newbrk;
29 
30 	__asm__ ("syscall\n"
31 		: "=a" (newbrk)
32 		: "0" (__NR_brk), "D" (addr)
33 		: "r11", "rcx"
34 	);
35 
36 	__curbrk = newbrk;
37 
38 	if (newbrk < addr) {
39 		__set_errno(ENOMEM);
40 		return -1;
41 	}
42 
43 	return 0;
44 }
45 libc_hidden_def(brk)
46