sysdeps/unix/sysv/linux/libc-start.c

   1 /* Copyright (C) 1998 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #include <link.h>
  20 #include <stdlib.h>
  21 #include <unistd.h>
  22
  23 extern void __libc_init_first (int argc, char **argv, char **envp);
  24
  25 extern int _dl_starting_up;
  26 weak_extern (_dl_starting_up)
  27 extern int __libc_multiple_libcs;
  28
  29 int
  30 __libc_start_main (int (*main) (int, char **, char **), int argc,
  31                    char **argv, void (*init) (void), void (*fini) (void),
  32                    void (*rtld_fini) (void))
  33 {
  34 #ifndef PIC
  35   /* The next variable is only here to work around a bug in gcc <= 2.7.2.2.
  36      If the address would be taken inside the expression the optimizer
  37      would try to be too smart and throws it away.  Grrr.  */
  38   int *dummy_addr = &_dl_starting_up;
  39
  40   __libc_multiple_libcs = dummy_addr && !_dl_starting_up;
  41 #endif
  42
  43   /* Register the destructor of the dynamic linker if there is any.  */
  44   if (rtld_fini != NULL)
  45     atexit (rtld_fini);
  46
  47   /* Set the global _environ variable correctly.  */
  48   __environ = &argv[argc + 1];
  49
  50   /* Call the initializer of the libc.  */
  51 #ifdef PIC
  52   if (_dl_debug_impcalls)
  53     _dl_debug_message (1, "\ninitialize libc\n\n", NULL);
  54 #endif
  55   __libc_init_first (argc, argv, __environ);
  56
  57   /* Call the initializer of the program.  */
  58 #ifdef PIC
  59   if (_dl_debug_impcalls)
  60     _dl_debug_message (1, "\ninitialize program: ", argv[0], "\n\n", NULL);
  61 #endif
  62   (*init) ();
  63
  64   /* Register the destructor of the program.  */
  65   atexit (fini);
  66
  67 #ifdef PIC
  68   if (_dl_debug_impcalls)
  69     _dl_debug_message (1, "\ntransferring control: ", argv[0], "\n\n", NULL);
  70 #endif
  71
  72   exit ((*main) (argc, argv, __environ));
  73 }