elf/dlopen.c

   1 /* dlopen -- Load a shared object at run time.
   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 #include <dlfcn.h>
  23
  24 void *
  25 dlopen (const char *file, dl_open_mode mode)
  26 {
  27   struct link_map *new, *l;
  28
  29   void doit (void)
  30     {
  31       Elf32_Addr init;
  32
  33       new = _dl_map_object (_dl_loaded, file);
  34
  35       /* Map in any dependencies.  */
  36       for (l = new; l; l = l->l_next)
  37         if (! l->l_deps_loaded)
  38           {
  39             if (l->l_info[DT_NEEDED])
  40               {
  41                 const char *strtab
  42                   = (void *) l->l_addr + l->l_info[DT_STRTAB]->d_un.d_ptr;
  43                 const Elf32_Dyn *d;
  44                 for (d = l->l_ld; d->d_tag != DT_NULL; ++d)
  45                   if (d->d_tag == DT_NEEDED)
  46                     _dl_map_object (l, strtab + d->d_un.d_val);
  47               }
  48             l->l_deps_loaded = 1;
  49           }
  50
  51       /* Relocate the objects loaded.  */
  52       for (l = new; l; l = l->l_next)
  53         if (! l->l_relocated)
  54           _dl_relocate_object (l, mode == RTLD_LAZY);
  55
  56       /* Run the initializer functions of new objects.  */
  57       while (init = _dl_init_next ())
  58         (*(void (*) (void)) init) ();
  59     }
  60
  61   return _dlerror_run (doit) ? NULL : new;
  62 }