csu/elf-init.c

   1 /* Startup support for ELF initializers/finalizers in the main executable.
   2    Copyright (C) 2002, 2003 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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <stddef.h>
  21
  22 #ifdef HAVE_INITFINI_ARRAY
  23 /* These magic symbols are provided by the linker.  */
  24 extern void (*__preinit_array_start []) (void) attribute_hidden;
  25 extern void (*__preinit_array_end []) (void) attribute_hidden;
  26 extern void (*__init_array_start []) (void) attribute_hidden;
  27 extern void (*__init_array_end []) (void) attribute_hidden;
  28 extern void (*__fini_array_start []) (void) attribute_hidden;
  29 extern void (*__fini_array_end []) (void) attribute_hidden;
  30 #endif
  31
  32 /* These function symbols are provided for the .init/.fini section entry
  33    points automagically by the linker.  */
  34 extern void _init (void);
  35 extern void _fini (void);
  36
  37 /* These functions are passed to __libc_start_main by the startup code.
  38    These get statically linked into each program.  For dynamically linked
  39    programs, this module will come from libc_nonshared.a and differs from
  40    the libc.a module in that it doesn't call the preinit array.  */
  41
  42 void
  43 __libc_csu_init (void)
  44 {
  45 #ifdef HAVE_INITFINI_ARRAY
  46   /* For dynamically linked executables the preinit array is executed by
  47      the dynamic linker (before initializing any shared object.  */
  48
  49 # ifndef LIBC_NONSHARED
  50   /* For static executables, preinit happens rights before init.  */
  51   {
  52     const size_t size = __preinit_array_end - __preinit_array_start;
  53     size_t i;
  54     for (i = 0; i < size; i++)
  55       (*__preinit_array_start [i]) ();
  56   }
  57 # endif
  58 #endif
  59
  60   _init ();
  61
  62 #ifdef HAVE_INITFINI_ARRAY
  63   {
  64     const size_t size = __init_array_end - __init_array_start;
  65     size_t i;
  66     for (i = 0; i < size; i++)
  67       (*__init_array_start [i]) ();
  68   }
  69 #endif
  70 }
  71
  72 void
  73 __libc_csu_fini (void)
  74 {
  75 #ifdef HAVE_INITFINI_ARRAY
  76   size_t i = __fini_array_end - __fini_array_start;
  77   while (i-- > 0)
  78     (*__fini_array_start [i]) ();
  79 #endif
  80
  81   _fini ();
  82 }