brk.c

来自「glibc 2.9,最新版的C语言库函数」· C语言 代码 · 共 57 行

/*
   Copyright (C) 2000 Free Software Foundation, Inc.
   Contributed by Martin Schwidefsky ([e-mail]).
   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, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <errno.h>
#include <unistd.h>
#include <sysdep.h>

void *__curbrk = 0;

/* Old braindamage in GCC's crtstuff.c requires this symbol in an attempt
   to work around different old braindamage in the old Linux/x86 ELF
   dynamic linker.  Sigh.  */
weak_alias (__curbrk, ___brk_addr)

int
__brk (void *addr)
{
  void *newbrk;

  {
    register void *__addr asm("2") = addr;

    asm ("svc  %b1\n\t"		/* call sys_brk */
	 : "=d" (__addr)
	 : "I" (SYS_ify(brk)), "r" (__addr)
	 : "cc", "memory" );
    newbrk = __addr;
  }
  __curbrk = newbrk;

  if (newbrk < addr)
    {
      __set_errno (ENOMEM);
      return -1;
    }

  return 0;
}
weak_alias (__brk, brk)