sysdeps/unix/sysv/linux/i386/brk.c

   1 /* brk system call for Linux/i386.
   2    Copyright (C) 1995, 1996, 2000, 2002, 2003 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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <errno.h>
  21 #include <unistd.h>
  22 #include <sysdep.h>
  23
  24 #include <bp-checks.h>
  25
  26 /* This must be initialized data because commons can't have aliases.  */
  27 void *__curbrk = 0;
  28
  29 /* Old braindamage in GCC's crtstuff.c requires this symbol in an attempt
  30    to work around different old braindamage in the old Linux ELF dynamic
  31    linker.  */
  32 weak_alias (__curbrk, ___brk_addr)
  33
  34 int
  35 __brk (void *addr)
  36 {
  37   void *__unbounded newbrk;
  38
  39   INTERNAL_SYSCALL_DECL (err);
  40   newbrk = (void *__unbounded) INTERNAL_SYSCALL (brk, err, 1,
  41                                                  __ptrvalue (addr));
  42
  43   __curbrk = newbrk;
  44
  45   if (newbrk < addr)
  46     {
  47       __set_errno (ENOMEM);
  48       return -1;
  49     }
  50
  51   return 0;
  52 }
  53 weak_alias (__brk, brk)