libc/sysdeps/linux/x86_64/brk.c

   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
  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)