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

   1 /* Initialization code run first thing by the ELF startup code.  Linux version.
   2    Copyright (C) 1995-1999, 2000, 2001, 2002 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 Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the 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    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <fcntl.h>
  23 #include <unistd.h>
  24 #include <sysdep.h>
  25 #include <fpu_control.h>
  26 #include <sys/param.h>
  27 #include <sys/types.h>
  28 #include "kernel-features.h"
  29 #include <libc-internal.h>
  30
  31 #include <ldsodefs.h>
  32 #ifndef SHARED
  33 # include "dl-osinfo.h"
  34 #endif
  35
  36 extern void __libc_init (int, char **, char **);
  37
  38 /* The function is called from assembly stubs the compiler can't see.  */
  39 static void init (int, char **, char **) __attribute__ ((unused));
  40
  41 extern int _dl_starting_up;
  42 weak_extern (_dl_starting_up)
  43
  44 extern int _dl_fpu_control_set;
  45
  46 /* Set nonzero if we have to be prepared for more then one libc being
  47    used in the process.  Safe assumption if initializer never runs.  */
  48 int __libc_multiple_libcs = 1;
  49
  50 /* Remember the command line argument and enviroment contents for
  51    later calls of initializers for dynamic libraries.  */
  52 int __libc_argc;
  53 char **__libc_argv;
  54
  55
  56 static void
  57 init (int argc, char **argv, char **envp)
  58 {
  59 #ifdef USE_NONOPTION_FLAGS
  60   extern void __getopt_clean_environment (char **);
  61 #endif
  62   /* The next variable is only here to work around a bug in gcc <= 2.7.2.2.
  63      If the address would be taken inside the expression the optimizer
  64      would try to be too smart and throws it away.  Grrr.  */
  65   int *dummy_addr = &_dl_starting_up;
  66
  67   __libc_multiple_libcs = dummy_addr && !_dl_starting_up;
  68
  69   /* Make sure we don't initialize twice.  */
  70   if (!__libc_multiple_libcs)
  71     {
  72 #ifndef SHARED
  73       DL_SYSDEP_OSCHECK (__libc_fatal);
  74 #endif
  75
  76       /* Set the FPU control word to the proper default value if the
  77          kernel would use a different value.  (In a static program we
  78          don't have this information.)  */
  79 #ifdef SHARED
  80       if (__fpu_control != GL(dl_fpu_control))
  81 #endif
  82         __setfpucw (__fpu_control);
  83     }
  84
  85   /* Save the command-line arguments.  */
  86   __libc_argc = argc;
  87   __libc_argv = argv;
  88   __environ = envp;
  89
  90 #ifndef SHARED
  91   __libc_init_secure ();
  92 #endif
  93
  94   __libc_init (argc, argv, envp);
  95
  96 #ifdef USE_NONOPTION_FLAGS
  97   /* This is a hack to make the special getopt in GNU libc working.  */
  98   __getopt_clean_environment (envp);
  99 #endif
 100
 101 #ifdef SHARED
 102   __libc_global_ctors ();
 103 #endif
 104 }
 105
 106 #ifdef SHARED
 107
 108 strong_alias (init, _init);
 109
 110 extern void __libc_init_first (void);
 111
 112 void
 113 __libc_init_first (void)
 114 {
 115 }
 116
 117 #else
 118 extern void __libc_init_first (int argc, char **argv, char **envp);
 119
 120 void
 121 __libc_init_first (int argc, char **argv, char **envp)
 122 {
 123   init (argc, argv, envp);
 124 }
 125 #endif
 126
 127
 128 /* This function is defined here so that if this file ever gets into
 129    ld.so we will get a link error.  Having this file silently included
 130    in ld.so causes disaster, because the _init definition above will
 131    cause ld.so to gain an init function, which is not a cool thing. */
 132
 133 extern void _dl_start (void) __attribute__ ((noreturn));
 134
 135 void
 136 _dl_start (void)
 137 {
 138   abort ();
 139 }