malloc/morecore.c

   1 /* Copyright (C) 1991-2022 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 static bool __always_fail_morecore = false;
  19
  20 /* Allocate INCREMENT more bytes of data space,
  21    and return the start of data space, or NULL on errors.
  22    If INCREMENT is negative, shrink data space.  */
  23 void *
  24 __glibc_morecore (ptrdiff_t increment)
  25 {
  26   if (__always_fail_morecore)
  27     return NULL;
  28
  29   void *result = (void *) __sbrk (increment);
  30   if (result == (void *) -1)
  31     return NULL;
  32
  33   return result;
  34 }
  35 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_34)
  36 compat_symbol (libc, __glibc_morecore, __default_morecore, GLIBC_2_0);
  37 #endif