sysdeps/unix/sysv/linux/brk.c

   1 /* Change data segment.  Linux generic version.
   2    Copyright (C) 2020-2024 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    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <unistd.h>
  21 #include <sysdep.h>
  22 #include <brk_call.h>
  23
  24 /* This must be initialized data because commons can't have aliases.  */
  25 void *__curbrk = 0;
  26
  27 #if HAVE_INTERNAL_BRK_ADDR_SYMBOL
  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 #endif
  33
  34 int
  35 __brk (void *addr)
  36 {
  37   __curbrk = __brk_call (addr);
  38   if (__curbrk < addr)
  39     {
  40       __set_errno (ENOMEM);
  41       return -1;
  42     }
  43
  44   return 0;
  45 }
  46 weak_alias (__brk, brk)