libio/freopen.c

   1 /* Copyright (C) 1993,95,96,97,98,2000,2001,2002,2003
   2         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    As a special exception, if you link the code in this file with
  21    files compiled with a GNU compiler to produce an executable,
  22    that does not cause the resulting executable to be covered by
  23    the GNU Lesser General Public License.  This exception does not
  24    however invalidate any other reasons why the executable file
  25    might be covered by the GNU Lesser General Public License.
  26    This exception applies to code released by its copyright holders
  27    in files containing the exception.  */
  28
  29 #include "libioP.h"
  30 #include "stdio.h"
  31 #include <stdlib.h>
  32
  33 #include <shlib-compat.h>
  34 #include <fd_to_filename.h>
  35
  36 FILE*
  37 freopen (filename, mode, fp)
  38      const char* filename;
  39      const char* mode;
  40      FILE* fp;
  41 {
  42   FILE *result;
  43   int fd = -1;
  44   CHECK_FILE (fp, NULL);
  45   if (!(fp->_flags & _IO_IS_FILEBUF))
  46     return NULL;
  47   _IO_acquire_lock (fp);
  48   if (filename == NULL && _IO_fileno (fp) >= 0)
  49     {
  50       fd = __dup (_IO_fileno (fp));
  51       if (fd != -1)
  52         filename = fd_to_filename (fd);
  53     }
  54 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1)
  55   if (&_IO_stdin_used == NULL)
  56     {
  57       /* If the shared C library is used by the application binary which
  58          was linked against the older version of libio, we just use the
  59          older one even for internal use to avoid trouble since a pointer
  60          to the old libio may be passed into shared C library and wind
  61          up here. */
  62       _IO_old_file_close_it (fp);
  63       _IO_JUMPS ((struct _IO_FILE_plus *) fp) = &_IO_old_file_jumps;
  64       result = _IO_old_file_fopen (fp, filename, mode);
  65     }
  66   else
  67 #endif
  68     {
  69       INTUSE(_IO_file_close_it) (fp);
  70       _IO_JUMPS ((struct _IO_FILE_plus *) fp) = &_IO_file_jumps;
  71       if (_IO_vtable_offset (fp) == 0 && fp->_wide_data != NULL)
  72         fp->_wide_data->_wide_vtable = &_IO_wfile_jumps;
  73       result = INTUSE(_IO_file_fopen) (fp, filename, mode, 1);
  74       if (result != NULL)
  75         result = __fopen_maybe_mmap (result);
  76     }
  77   if (result != NULL)
  78     /* unbound stream orientation */
  79     result->_mode = 0;
  80   if (fd != -1)
  81     {
  82       __close (fd);
  83       if (filename != NULL)
  84         free ((char *) filename);
  85     }
  86   _IO_release_lock (fp);
  87   return result;
  88 }