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

   1 /* Initialization code run first thing by the ELF startup code.  Linux version.
   2    Copyright (C) 1995, 1996, 1997, 1998 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 <unistd.h>
  21 #include <sysdep.h>
  22 #include <fpu_control.h>
  23 #include <linux/personality.h>
  24 #include <init-first.h>
  25 #include <sys/types.h>
  26
  27 extern void __libc_init_secure (void);
  28 extern void __libc_init (int, char **, char **);
  29 extern void __libc_global_ctors (void);
  30
  31 /* The function is called from assembly stubs the compiler can't see.  */
  32 static void init (int, char **, char **) __attribute__ ((unused));
  33
  34 extern int _dl_starting_up;
  35 weak_extern (_dl_starting_up)
  36
  37 /* Set nonzero if we have to be prepared for more then one libc being
  38    used in the process.  Safe assumption if initializer never runs.  */
  39 int __libc_multiple_libcs = 1;
  40
  41 /* Remember the command line argument and enviroment contents for
  42    later calls of initializers for dynamic libraries.  */
  43 int __libc_argc;
  44 char **__libc_argv;
  45
  46
  47 static void
  48 init (int argc, char **argv, char **envp)
  49 {
  50   extern int __personality (int);
  51   extern void __getopt_clean_environment (char **);
  52
  53   /* We must not call `personality' twice.  */
  54   if (!__libc_multiple_libcs)
  55     {
  56       /* The `personality' system call takes one argument that chooses
  57          the "personality", i.e. the set of system calls and such.  We
  58          must make this call first thing to disable emulation of some
  59          other system that might have been enabled by default based on
  60          the executable format.  */
  61       __personality (PER_LINUX);
  62
  63       /* Set the FPU control word to the proper default value if the
  64          kernel would use a different value.  */
  65       if (__fpu_control != _FPU_DEFAULT)
  66         __setfpucw (__fpu_control);
  67     }
  68
  69   /* Save the command-line arguments.  */
  70   __libc_argc = argc;
  71   __libc_argv = argv;
  72   __environ = envp;
  73
  74 #ifndef PIC
  75   __libc_init_secure ();
  76 #endif
  77
  78   __libc_init (argc, argv, envp);
  79
  80   /* This is a hack to make the special getopt in GNU libc working.  */
  81   __getopt_clean_environment (envp);
  82
  83 #ifdef PIC
  84   __libc_global_ctors ();
  85 #endif
  86 }
  87
  88 #ifdef PIC
  89
  90 SYSDEP_CALL_INIT(_init, init);
  91
  92 void
  93 __libc_init_first (void)
  94 {
  95 }
  96
  97 #else
  98 void
  99 __libc_init_first (int argc, char **argv, char **envp)
 100 {
 101   init (argc, argv, envp);
 102 }
 103 #endif
 104
 105
 106 /* This function is defined here so that if this file ever gets into
 107    ld.so we will get a link error.  Having this file silently included
 108    in ld.so causes disaster, because the _init definition above will
 109    cause ld.so to gain an init function, which is not a cool thing. */
 110
 111 void
 112 _dl_start (void)
 113 {
 114   abort ();
 115 }