1  /* Copyright (C) 1993-2023 Free Software Foundation, Inc.
       2     This file is part of the GNU C Library.
       3  
       4     The GNU C Library is free software; you can redistribute it and/or
       5     modify it under the terms of the GNU Lesser General Public
       6     License as published by the Free Software Foundation; either
       7     version 2.1 of the License, or (at your option) any later version.
       8  
       9     The GNU C Library is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12     Lesser General Public License for more details.
      13  
      14     You should have received a copy of the GNU Lesser General Public
      15     License along with the GNU C Library; if not, see
      16     <https://www.gnu.org/licenses/>.
      17  
      18     As a special exception, if you link the code in this file with
      19     files compiled with a GNU compiler to produce an executable,
      20     that does not cause the resulting executable to be covered by
      21     the GNU Lesser General Public License.  This exception does not
      22     however invalidate any other reasons why the executable file
      23     might be covered by the GNU Lesser General Public License.
      24     This exception applies to code released by its copyright holders
      25     in files containing the exception.  */
      26  
      27  #include <shlib-compat.h>
      28  #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1)
      29  
      30  /* This file provides legacy definitions of _IO_stdin_, _IO_stdout_,
      31     and _IO_stderr_.  See stdfiles.c for the current definitions.  */
      32  
      33  #define _IO_USE_OLD_IO_FILE
      34  #include "libioP.h"
      35  
      36  #ifdef _IO_MTSAFE_IO
      37  #define DEF_STDFILE(NAME, FD, CHAIN, FLAGS) \
      38    static _IO_lock_t _IO_stdfile_##FD##_lock = _IO_lock_initializer; \
      39    struct _IO_FILE_plus NAME \
      40      = {FILEBUF_LITERAL(CHAIN, FLAGS, FD, NULL), &_IO_old_file_jumps};
      41  #else
      42  #define DEF_STDFILE(NAME, FD, CHAIN, FLAGS) \
      43    struct _IO_FILE_plus NAME \
      44      = {FILEBUF_LITERAL(CHAIN, FLAGS, FD, NULL), &_IO_old_file_jumps};
      45  #endif
      46  
      47  DEF_STDFILE(_IO_stdin_, 0, 0, _IO_NO_WRITES);
      48  DEF_STDFILE(_IO_stdout_, 1, &_IO_stdin_, _IO_NO_READS);
      49  DEF_STDFILE(_IO_stderr_, 2, &_IO_stdout_, _IO_NO_READS+_IO_UNBUFFERED);
      50  
      51  #if defined __GNUC__ && __GNUC__ >= 2
      52  
      53  #include <stdio.h>
      54  
      55  extern const int _IO_stdin_used;
      56  weak_extern (_IO_stdin_used);
      57  
      58  #undef stdin
      59  #undef stdout
      60  #undef stderr
      61  
      62  extern FILE *stdin;
      63  extern FILE *stdout;
      64  extern FILE *stderr;
      65  
      66  static void _IO_check_libio (void) __THROW __attribute__ ((constructor));
      67  
      68  /* This function determines which shared C library the application
      69     was linked against. We then set up the stdin/stdout/stderr and
      70     _IO_list_all accordingly. */
      71  
      72  static void
      73  _IO_check_libio (void)
      74  {
      75    if (&_IO_stdin_used == NULL)
      76      {
      77        /* We are using the old one. */
      78        stdin = (FILE *) &_IO_stdin_;
      79        stdout = (FILE *) &_IO_stdout_;
      80        stderr = (FILE *) &_IO_stderr_;
      81        _IO_list_all = &_IO_stderr_;
      82        stdin->_vtable_offset = stdout->_vtable_offset
      83  	= stderr->_vtable_offset =
      84  	((int) sizeof (struct _IO_FILE)
      85  	 - (int) sizeof (struct _IO_FILE_complete));
      86  
      87        if (_IO_stdin_.vtable != &_IO_old_file_jumps
      88  	  || _IO_stdout_.vtable != &_IO_old_file_jumps
      89  	  || _IO_stderr_.vtable != &_IO_old_file_jumps)
      90  	IO_set_accept_foreign_vtables (&_IO_vtable_check);
      91      }
      92  }
      93  
      94  #endif
      95  
      96  #endif