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 "libioP.h"
      28  #include <fcntl.h>
      29  #include <stdlib.h>
      30  #include <stddef.h>
      31  #include <shlib-compat.h>
      32  
      33  FILE *
      34  __fopen_maybe_mmap (FILE *fp)
      35  {
      36  #if _G_HAVE_MMAP
      37    if ((fp->_flags2 & _IO_FLAGS2_MMAP) && (fp->_flags & _IO_NO_WRITES))
      38      {
      39        /* Since this is read-only, we might be able to mmap the contents
      40  	 directly.  We delay the decision until the first read attempt by
      41  	 giving it a jump table containing functions that choose mmap or
      42  	 vanilla file operations and reset the jump table accordingly.  */
      43  
      44        if (fp->_mode <= 0)
      45  	_IO_JUMPS_FILE_plus (fp) = &_IO_file_jumps_maybe_mmap;
      46        else
      47  	_IO_JUMPS_FILE_plus (fp) = &_IO_wfile_jumps_maybe_mmap;
      48        fp->_wide_data->_wide_vtable = &_IO_wfile_jumps_maybe_mmap;
      49      }
      50  #endif
      51    return fp;
      52  }
      53  
      54  
      55  FILE *
      56  __fopen_internal (const char *filename, const char *mode, int is32)
      57  {
      58    struct locked_FILE
      59    {
      60      struct _IO_FILE_plus fp;
      61  #ifdef _IO_MTSAFE_IO
      62      _IO_lock_t lock;
      63  #endif
      64      struct _IO_wide_data wd;
      65    } *new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
      66  
      67    if (new_f == NULL)
      68      return NULL;
      69  #ifdef _IO_MTSAFE_IO
      70    new_f->fp.file._lock = &new_f->lock;
      71  #endif
      72    _IO_no_init (&new_f->fp.file, 0, 0, &new_f->wd, &_IO_wfile_jumps);
      73    _IO_JUMPS (&new_f->fp) = &_IO_file_jumps;
      74    _IO_new_file_init_internal (&new_f->fp);
      75    if (_IO_file_fopen ((FILE *) new_f, filename, mode, is32) != NULL)
      76      return __fopen_maybe_mmap (&new_f->fp.file);
      77  
      78    _IO_un_link (&new_f->fp);
      79    free (new_f);
      80    return NULL;
      81  }
      82  
      83  FILE *
      84  _IO_new_fopen (const char *filename, const char *mode)
      85  {
      86    return __fopen_internal (filename, mode, 1);
      87  }
      88  
      89  strong_alias (_IO_new_fopen, __new_fopen)
      90  versioned_symbol (libc, _IO_new_fopen, _IO_fopen, GLIBC_2_1);
      91  versioned_symbol (libc, __new_fopen, fopen, GLIBC_2_1);
      92  
      93  # if !defined O_LARGEFILE || O_LARGEFILE == 0
      94  weak_alias (_IO_new_fopen, _IO_fopen64)
      95  weak_alias (_IO_new_fopen, fopen64)
      96  # endif