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 <ctype.h>
  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 <libc-internal.h>
  29
  30 #include <ldsodefs.h>
  31
  32 /* Set nonzero if we have to be prepared for more than one libc being
  33    used in the process.  Safe assumption if initializer never runs.  */
  34 int __libc_multiple_libcs attribute_hidden = 1;
  35
  36 /* Remember the command line argument and enviroment contents for
  37    later calls of initializers for dynamic libraries.  */
  38 int __libc_argc attribute_hidden;
  39 char **__libc_argv attribute_hidden;
  40
  41
  42 void
  43 __libc_init_first (int argc, char **argv, char **envp)
  44 {
  45 #ifdef SHARED
  46   /* For DSOs we do not need __libc_init_first but an ELF constructor.  */
  47 }
  48
  49 static void __attribute__ ((constructor))
  50 _init_first (int argc, char **argv, char **envp)
  51 {
  52 #endif
  53
  54   __libc_multiple_libcs = &_dl_starting_up && !_dl_starting_up;
  55
  56   /* Make sure we don't initialize twice.  */
  57   if (!__libc_multiple_libcs)
  58     {
  59       /* Set the FPU control word to the proper default value if the
  60          kernel would use a different value.  */
  61       if (__fpu_control != GLRO(dl_fpu_control))
  62         __setfpucw (__fpu_control);
  63     }
  64
  65   /* Save the command-line arguments.  */
  66   __libc_argc = argc;
  67   __libc_argv = argv;
  68   __environ = envp;
  69
  70 #ifndef SHARED
  71   /* First the initialization which normally would be done by the
  72      dynamic linker.  */
  73   _dl_non_dynamic_init ();
  74 #endif
  75
  76   __init_misc (argc, argv, envp);
  77
  78   /* Initialize ctype data.  */
  79   __ctype_init ();
  80
  81 #if defined SHARED && !defined NO_CTORS_DTORS_SECTIONS
  82   __libc_global_ctors ();
  83 #endif
  84 }
  85
  86 /* This function is defined here so that if this file ever gets into
  87    ld.so we will get a link error.  Having this file silently included
  88    in ld.so causes disaster, because the _init_first definition above
  89    will cause ld.so to gain an ELF constructor, which is not a cool
  90    thing. */
  91
  92 extern void _dl_start (void) __attribute__ ((noreturn));
  93
  94 void
  95 _dl_start (void)
  96 {
  97   abort ();
  98 }