csu/init-first.c

   1 /* Initialization code run first thing by the ELF startup code.  Common version
   2    Copyright (C) 1995-2020 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, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <fcntl.h>
  22 #include <unistd.h>
  23 #include <sysdep.h>
  24 #include <fpu_control.h>
  25 #include <sys/param.h>
  26 #include <sys/types.h>
  27 #include <libc-internal.h>
  28
  29 #include <ldsodefs.h>
  30
  31 /* Set nonzero if we have to be prepared for more than one libc being
  32    used in the process.  Safe assumption if initializer never runs.  */
  33 int __libc_multiple_libcs attribute_hidden = 1;
  34
  35 /* Remember the command line argument and enviroment contents for
  36    later calls of initializers for dynamic libraries.  */
  37 int __libc_argc attribute_hidden;
  38 char **__libc_argv attribute_hidden;
  39
  40
  41 void
  42 __libc_init_first (int argc, char **argv, char **envp)
  43 {
  44 #ifdef SHARED
  45   /* For DSOs we do not need __libc_init_first but an ELF constructor.  */
  46 }
  47
  48 static void __attribute__ ((constructor))
  49 _init_first (int argc, char **argv, char **envp)
  50 {
  51 #endif
  52
  53   __libc_multiple_libcs = &_dl_starting_up && !_dl_starting_up;
  54
  55   /* Make sure we don't initialize twice.  */
  56   if (!__libc_multiple_libcs)
  57     {
  58       /* Set the FPU control word to the proper default value if the
  59          kernel would use a different value.  */
  60       if (__fpu_control != GLRO(dl_fpu_control))
  61         __setfpucw (__fpu_control);
  62     }
  63
  64   /* Save the command-line arguments.  */
  65   __libc_argc = argc;
  66   __libc_argv = argv;
  67   __environ = envp;
  68
  69 #ifndef SHARED
  70   /* First the initialization which normally would be done by the
  71      dynamic linker.  */
  72   _dl_non_dynamic_init ();
  73 #endif
  74
  75   __init_misc (argc, argv, envp);
  76 }
  77
  78 /* This function is defined here so that if this file ever gets into
  79    ld.so we will get a link error.  Having this file silently included
  80    in ld.so causes disaster, because the _init_first definition above
  81    will cause ld.so to gain an ELF constructor, which is not a cool
  82    thing. */
  83
  84 extern void _dl_start (void) __attribute__ ((noreturn));
  85
  86 void
  87 _dl_start (void)
  88 {
  89   abort ();
  90 }