elf/dl-call-libc-early-init.c

   1 /* Invoke the early initialization function in libc.so.
   2    Copyright (C) 2020 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 <assert.h>
  20 #include <ldsodefs.h>
  21 #include <libc-early-init.h>
  22 #include <link.h>
  23 #include <stddef.h>
  24
  25 void
  26 _dl_call_libc_early_init (struct link_map *libc_map, _Bool initial)
  27 {
  28   /* There is nothing to do if we did not actually load libc.so.  */
  29   if (libc_map == NULL)
  30     return;
  31
  32   const ElfW(Sym) *sym
  33     = _dl_lookup_direct (libc_map, "__libc_early_init",
  34                          0x069682ac, /* dl_new_hash output.  */
  35                          "GLIBC_PRIVATE",
  36                          0x0963cf85); /* _dl_elf_hash output.  */
  37   assert (sym != NULL);
  38   __typeof (__libc_early_init) *early_init
  39     = DL_SYMBOL_ADDRESS (libc_map, sym);
  40   early_init (initial);
  41 }