elf/dl-init.c

   1 /* Return the next shared object initializer function not yet run.
   2 Copyright (C) 1995 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 Library General Public License as
   7 published by the Free Software Foundation; either version 2 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 Library General Public License for more details.
  14
  15 You should have received a copy of the GNU Library General Public
  16 License along with the GNU C Library; see the file COPYING.LIB.  If
  17 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  18 Cambridge, MA 02139, USA.  */
  19
  20 #include <stddef.h>
  21 #include <link.h>
  22
  23
  24 Elf32_Addr
  25 _dl_init_next (void)
  26 {
  27   struct link_map *l;
  28   Elf32_Addr init;
  29
  30   Elf32_Addr next_init (struct link_map *l)
  31     {
  32       if (l->l_init_called)
  33         /* This object is all done.  */
  34         return 0;
  35       if (l->l_init_running)
  36         {
  37           /* This object's initializer was just running.
  38              Now mark it as having run, so this object
  39              will be skipped in the future.  */
  40           l->l_init_called = 1;
  41           l->l_init_running = 0;
  42           return 0;
  43         }
  44
  45       if (l->l_info[DT_NEEDED])
  46         {
  47           /* Find each dependency in order, and see if it
  48              needs to run an initializer.  */
  49           const char *strtab
  50             = ((void *) l->l_addr + l->l_info[DT_STRTAB]->d_un.d_ptr);
  51           const Elf32_Dyn *d;
  52           for (d = l->l_ld; d->d_tag != DT_NULL; ++d)
  53             if (d->d_tag == DT_NEEDED)
  54               {
  55                 struct link_map *needed
  56                   = _dl_map_object (l, strtab + d->d_un.d_val);
  57                 Elf32_Addr init;
  58                 --needed->l_opencount;
  59                 init = next_init (needed); /* Recurse on this dependency.  */
  60                 if (init != 0)
  61                   return init;
  62               }
  63         }
  64
  65       if (l->l_info[DT_INIT])
  66         {
  67           /* Run this object's initializer.  */
  68           l->l_init_running = 1;
  69           return l->l_addr + l->l_info[DT_INIT]->d_un.d_ptr;
  70         }
  71
  72       /* No initializer for this object.
  73          Mark it so we will skip it in the future.  */
  74       l->l_init_called = 1;
  75       return 0;
  76     }
  77
  78   /* Look for the first initializer not yet called.  */
  79   l = _dl_loaded->l_next;       /* Skip the executable itself.  */
  80   do
  81     {
  82       init = next_init (l);
  83       l = l->l_next;
  84     }
  85   while (init == 0 && l);
  86
  87   return init;
  88 }