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 extern fpu_control_t _dl_fpu_control;
  38 extern int _dl_fpu_control_set;
  39
  40 /* Set nonzero if we have to be prepared for more then one libc being
  41    used in the process.  Safe assumption if initializer never runs.  */
  42 int __libc_multiple_libcs = 1;
  43
  44 /* Remember the command line argument and enviroment contents for
  45    later calls of initializers for dynamic libraries.  */
  46 int __libc_argc;
  47 char **__libc_argv;
  48
  49
  50 static void
  51 init (int argc, char **argv, char **envp)
  52 {
  53   extern int __personality (int);
  54   extern void __getopt_clean_environment (char **);
  55
  56   /* We must not call `personality' twice.  */
  57   if (!__libc_multiple_libcs)
  58     {
  59       /* The `personality' system call takes one argument that chooses
  60          the "personality", i.e. the set of system calls and such.  We
  61          must make this call first thing to disable emulation of some
  62          other system that might have been enabled by default based on
  63          the executable format.  */
  64       __personality (PER_LINUX);
  65
  66       /* Set the FPU control word to the proper default value if the
  67          kernel would use a different value.  (In a static program we
  68          don't have this information.)  */
  69 #ifdef PIC
  70       if (__fpu_control != _dl_fpu_control)
  71 #endif
  72         __setfpucw (__fpu_control);
  73     }
  74
  75   /* Save the command-line arguments.  */
  76   __libc_argc = argc;
  77   __libc_argv = argv;
  78   __environ = envp;
  79
  80 #ifndef PIC
  81   __libc_init_secure ();
  82 #endif
  83
  84   __libc_init (argc, argv, envp);
  85
  86   /* This is a hack to make the special getopt in GNU libc working.  */
  87   __getopt_clean_environment (envp);
  88
  89 #ifdef PIC
  90   __libc_global_ctors ();
  91 #endif
  92 }
  93
  94 #ifdef PIC
  95
  96 SYSDEP_CALL_INIT(_init, init);
  97
  98 void
  99 __libc_init_first (void)
 100 {
 101 }
 102
 103 #else
 104 void
 105 __libc_init_first (int argc, char **argv, char **envp)
 106 {
 107   init (argc, argv, envp);
 108 }
 109 #endif
 110
 111
 112 /* This function is defined here so that if this file ever gets into
 113    ld.so we will get a link error.  Having this file silently included
 114    in ld.so causes disaster, because the _init definition above will
 115    cause ld.so to gain an init function, which is not a cool thing. */
 116
 117 void
 118 _dl_start (void)
 119 {
 120   abort ();
 121 }