sysdeps/unix/sysv/linux/i386/init-first.c

   1 /* Initialization code run first thing by the ELF startup code.  i386/Linux
   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 <unistd.h>
  21 #include "fpu_control.h"
  22
  23 extern void __libc_init (int, char **, char **);
  24 extern void __libc_global_ctors (void);
  25
  26
  27 static void
  28 init (int *data)
  29 {
  30   int argc = *data;
  31   char **argv = (void *) (data + 1);
  32   char **envp = &argv[argc + 1];
  33
  34   /* Make sure we are not using iBSC2 personality.  */
  35   asm ("int $0x80 # syscall no %0, arg %1"
  36        : : "a" (SYS_ify (personality)), "b" (0));
  37
  38   /* Set the FPU control word to the proper default value.  */
  39   __setfpucw (___fpu_control);
  40
  41   __environ = envp;
  42   __libc_init (argc, argv, envp);
  43 }
  44
  45 #ifdef PIC
  46 /* This function is called to initialize the shared C library.
  47    It is called just before the user _start code from i386/elf/start.S,
  48    with the stack set up as that code gets it.  */
  49
  50 /* NOTE!  The linker notices the magical name `_init' and sets the DT_INIT
  51    pointer in the dynamic section based solely on that.  It is convention
  52    for this function to be in the `.init' section, but the symbol name is
  53    the only thing that really matters!!  */
  54 /*void _init (int argc, ...) __attribute__ ((unused, section (".init")));*/
  55
  56 void
  57 _init (int argc, ...)
  58 {
  59   init (&argc);
  60
  61   __libc_global_ctors ();
  62 }
  63 #endif
  64
  65
  66 void
  67 __libc_init_first (int argc __attribute__ ((unused)), ...)
  68 {
  69 #ifndef PIC
  70   init (&argc);
  71 #endif
  72 }