libio/freopen64.c

   1 /* Copyright (C) 1993-2012 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    <http://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 "libioP.h"
  28 #include "stdio.h"
  29 #include <fcntl.h>
  30 #include <stdlib.h>
  31 #include <unistd.h>
  32
  33 #include <fd_to_filename.h>
  34
  35 #include <kernel-features.h>
  36
  37 FILE *
  38 freopen64 (filename, mode, fp)
  39      const char* filename;
  40      const char* mode;
  41      FILE *fp;
  42 {
  43 #ifdef _G_OPEN64
  44   FILE *result;
  45   CHECK_FILE (fp, NULL);
  46   if (!(fp->_flags & _IO_IS_FILEBUF))
  47     return NULL;
  48   _IO_acquire_lock (fp);
  49   int fd = _IO_fileno (fp);
  50   const char *gfilename = (filename == NULL && fd >= 0
  51                            ? fd_to_filename (fd) : filename);
  52   fp->_flags2 |= _IO_FLAGS2_NOCLOSE;
  53   _IO_file_close_it (fp);
  54   _IO_JUMPS ((struct _IO_FILE_plus *) fp) = &_IO_file_jumps;
  55   if (_IO_vtable_offset (fp) == 0 && fp->_wide_data != NULL)
  56     fp->_wide_data->_wide_vtable = &_IO_wfile_jumps;
  57   result = _IO_file_fopen (fp, gfilename, mode, 0);
  58   fp->_flags2 &= ~_IO_FLAGS2_NOCLOSE;
  59   if (result != NULL)
  60     result = __fopen_maybe_mmap (result);
  61   if (result != NULL)
  62     {
  63       /* unbound stream orientation */
  64       result->_mode = 0;
  65
  66       if (fd != -1)
  67         {
  68 #ifdef O_CLOEXEC
  69 # ifndef __ASSUME_DUP3
  70           int newfd;
  71           if (__have_dup3 < 0)
  72             newfd = -1;
  73           else
  74             newfd =
  75 # endif
  76               __dup3 (_IO_fileno (result), fd,
  77                       (result->_flags2 & _IO_FLAGS2_CLOEXEC) != 0
  78                       ? O_CLOEXEC : 0);
  79 #else
  80 # define newfd 1
  81 #endif
  82
  83 #ifndef __ASSUME_DUP3
  84           if (newfd < 0)
  85             {
  86               if (errno == ENOSYS)
  87                 __have_dup3 = -1;
  88
  89               __dup2 (_IO_fileno (result), fd);
  90               if ((result->_flags2 & _IO_FLAGS2_CLOEXEC) != 0)
  91                 __fcntl (fd, F_SETFD, FD_CLOEXEC);
  92             }
  93 #endif
  94           __close (_IO_fileno (result));
  95           _IO_fileno (result) = fd;
  96         }
  97     }
  98   else if (fd != -1)
  99     __close (fd);
 100   if (filename == NULL)
 101     free ((char *) gfilename);
 102   _IO_release_lock (fp);
 103   return result;
 104 #else
 105   __set_errno (ENOSYS);
 106   return NULL;
 107 #endif
 108 }