elf/dl-init.c

   1 /* Return the next shared object initializer function not yet run.
   2    Copyright (C) 1995, 1996, 1998, 1999, 2000 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 not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <stddef.h>
  21 #include <ldsodefs.h>
  22
  23
  24 /* Type of the initializer.  */
  25 typedef void (*init_t) (int, char **, char **);
  26
  27 /* Flag, nonzero during startup phase.  */
  28 extern int _dl_starting_up;
  29
  30
  31 void
  32 internal_function
  33 _dl_init (struct link_map *main_map, int argc, char **argv, char **env)
  34 {
  35   ElfW(Dyn) *preinit_array = main_map->l_info[DT_PREINIT_ARRAY];
  36   struct r_debug *r;
  37   unsigned int i;
  38
  39   /* Don't do anything if there is no preinit array.  */
  40   if (preinit_array != NULL
  41       && (i = preinit_array->d_un.d_val / sizeof (ElfW(Addr))) > 0)
  42     {
  43       ElfW(Addr) *addrs;
  44       unsigned int cnt;
  45
  46       if (__builtin_expect (_dl_debug_impcalls, 0))
  47         _dl_debug_message (1, "\ncalling preinit: ",
  48                            main_map->l_name[0]
  49                            ? main_map->l_name : _dl_argv[0], "\n\n", NULL);
  50
  51       addrs = (ElfW(Addr) *) (main_map->l_info[DT_PREINIT_ARRAY]->d_un.d_ptr
  52                               + main_map->l_addr);
  53       for (cnt = 0; cnt < i; ++cnt)
  54         ((init_t) addrs[cnt]) (argc, argv, env);
  55     }
  56
  57   /* Notify the debugger we have added some objects.  We need to call
  58      _dl_debug_initialize in a static program in case dynamic linking has
  59      not been used before.  */
  60   r = _dl_debug_initialize (0);
  61   r->r_state = RT_ADD;
  62   _dl_debug_state ();
  63
  64   /* Stupid users forces the ELF specification to be changed.  It now
  65      says that the dynamic loader is responsible for determining the
  66      order in which the constructors have to run.  The constructors
  67      for all dependencies of an object must run before the constructor
  68      for the object itself.  Circular dependencies are left unspecified.
  69
  70      This is highly questionable since it puts the burden on the dynamic
  71      loader which has to find the dependencies at runtime instead of
  72      letting the user do it right.  Stupidity rules!  */
  73
  74   i = main_map->l_searchlist.r_nlist;
  75   while (i-- > 0)
  76     {
  77       struct link_map *l = main_map->l_initfini[i];
  78       init_t init;
  79
  80       if (l->l_init_called)
  81         /* This object is all done.  */
  82         continue;
  83
  84       /* Avoid handling this constructor again in case we have a circular
  85          dependency.  */
  86       l->l_init_called = 1;
  87
  88       /* Check for object which constructors we do not run here.  */
  89       if (l->l_name[0] == '\0' && l->l_type == lt_executable)
  90         continue;
  91
  92       /* Are there any constructors?  */
  93       if (l->l_info[DT_INIT] == NULL && l->l_info[DT_INIT_ARRAY] == NULL)
  94         continue;
  95
  96       /* Print a debug message if wanted.  */
  97       if (__builtin_expect (_dl_debug_impcalls, 0))
  98         _dl_debug_message (1, "\ncalling init: ",
  99                            l->l_name[0] ? l->l_name : _dl_argv[0],
 100                            "\n\n", NULL);
 101
 102       /* Now run the local constructors.  There are two forms of them:
 103          - the one named by DT_INIT
 104          - the others in the DT_INIT_ARRAY.
 105       */
 106       if (l->l_info[DT_INIT] != NULL)
 107         {
 108           init = (init_t) DL_DT_INIT_ADDRESS
 109             (l, l->l_addr + l->l_info[DT_INIT]->d_un.d_ptr);
 110
 111           /* Call the function.  */
 112           init (argc, argv, env);
 113         }
 114
 115       /* Next see whether there is an array with initialization functions.  */
 116       if (l->l_info[DT_INIT_ARRAY] != NULL)
 117         {
 118           unsigned int j;
 119           unsigned int jm;
 120           ElfW(Addr) *addrs;
 121
 122           jm = l->l_info[DT_INIT_ARRAYSZ]->d_un.d_val / sizeof (ElfW(Addr));
 123
 124           addrs = (ElfW(Addr) *) (l->l_info[DT_INIT_ARRAY]->d_un.d_ptr
 125                                   + l->l_addr);
 126           for (j = 0; j < jm; ++j)
 127             ((init_t) addrs[j]) (argc, argv, env);
 128         }
 129     }
 130
 131   /* Notify the debugger all new objects are now ready to go.  */
 132   r->r_state = RT_CONSISTENT;
 133   _dl_debug_state ();
 134
 135   /* Finished starting up.  */
 136   _dl_starting_up = 0;
 137 }