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

   1 /* brk system call for Linux/i386.
   2    Copyright (C) 1995-2013 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 <sysdep.h>
  22
  23 #include <bp-checks.h>
  24
  25 /* This must be initialized data because commons can't have aliases.  */
  26 void *__curbrk = 0;
  27
  28 /* Old braindamage in GCC's crtstuff.c requires this symbol in an attempt
  29    to work around different old braindamage in the old Linux ELF dynamic
  30    linker.  */
  31 weak_alias (__curbrk, ___brk_addr)
  32
  33 int
  34 __brk (void *addr)
  35 {
  36   void *__unbounded newbrk;
  37
  38   INTERNAL_SYSCALL_DECL (err);
  39   newbrk = (void *__unbounded) INTERNAL_SYSCALL (brk, err, 1,
  40                                                  __ptrvalue (addr));
  41
  42   __curbrk = newbrk;
  43
  44   if (newbrk < addr)
  45     {
  46       __set_errno (ENOMEM);
  47       return -1;
  48     }
  49
  50   return 0;
  51 }
  52 weak_alias (__brk, brk)