malloc/reallocarray.c

   1 /* Change the size of an allocated block.
   2    Copyright (C) 2017-2023 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 License as
   7    published by the Free Software Foundation; either version 2.1 of the
   8    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; see the file COPYING.LIB.  If
  17    not, see <https://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <stdlib.h>
  21 #include <malloc.h>
  22
  23 void *
  24 __libc_reallocarray (void *optr, size_t nmemb, size_t elem_size)
  25 {
  26   size_t bytes;
  27   if (__builtin_mul_overflow (nmemb, elem_size, &bytes))
  28     {
  29       __set_errno (ENOMEM);
  30       return 0;
  31     }
  32   return realloc (optr, bytes);
  33 }
  34 libc_hidden_def (__libc_reallocarray)
  35
  36 weak_alias (__libc_reallocarray, reallocarray)