libio/iofopen.c

   1 /* Copyright (C) 1993,1997,1998,1999,2000,2002,2003,2012
   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 <stdlib.h>
  31 #include <stddef.h>
  32 #ifdef _LIBC
  33 # include <shlib-compat.h>
  34 #else
  35 # define _IO_new_fopen fopen
  36 #endif
  37
  38 _IO_FILE *
  39 __fopen_maybe_mmap (fp)
  40      _IO_FILE *fp;
  41 {
  42 #ifdef _G_HAVE_MMAP
  43   if ((fp->_flags2 & _IO_FLAGS2_MMAP) && (fp->_flags & _IO_NO_WRITES))
  44     {
  45       /* Since this is read-only, we might be able to mmap the contents
  46          directly.  We delay the decision until the first read attempt by
  47          giving it a jump table containing functions that choose mmap or
  48          vanilla file operations and reset the jump table accordingly.  */
  49
  50       if (fp->_mode <= 0)
  51         _IO_JUMPS ((struct _IO_FILE_plus *) fp) = &_IO_file_jumps_maybe_mmap;
  52       else
  53         _IO_JUMPS ((struct _IO_FILE_plus *) fp) = &_IO_wfile_jumps_maybe_mmap;
  54       fp->_wide_data->_wide_vtable = &_IO_wfile_jumps_maybe_mmap;
  55     }
  56 #endif
  57   return fp;
  58 }
  59
  60
  61 _IO_FILE *
  62 __fopen_internal (filename, mode, is32)
  63      const char *filename;
  64      const char *mode;
  65      int is32;
  66 {
  67   struct locked_FILE
  68   {
  69     struct _IO_FILE_plus fp;
  70 #ifdef _IO_MTSAFE_IO
  71     _IO_lock_t lock;
  72 #endif
  73     struct _IO_wide_data wd;
  74   } *new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
  75
  76   if (new_f == NULL)
  77     return NULL;
  78 #ifdef _IO_MTSAFE_IO
  79   new_f->fp.file._lock = &new_f->lock;
  80 #endif
  81 #if defined _LIBC || defined _GLIBCPP_USE_WCHAR_T
  82   _IO_no_init (&new_f->fp.file, 0, 0, &new_f->wd, &_IO_wfile_jumps);
  83 #else
  84   _IO_no_init (&new_f->fp.file, 1, 0, NULL, NULL);
  85 #endif
  86   _IO_JUMPS (&new_f->fp) = &_IO_file_jumps;
  87   INTUSE(_IO_file_init) (&new_f->fp);
  88 #if  !_IO_UNIFIED_JUMPTABLES
  89   new_f->fp.vtable = NULL;
  90 #endif
  91   if (INTUSE(_IO_file_fopen) ((_IO_FILE *) new_f, filename, mode, is32)
  92       != NULL)
  93     return __fopen_maybe_mmap (&new_f->fp.file);
  94
  95   INTUSE(_IO_un_link) (&new_f->fp);
  96   free (new_f);
  97   return NULL;
  98 }
  99
 100 _IO_FILE *
 101 _IO_new_fopen (filename, mode)
 102      const char *filename;
 103      const char *mode;
 104 {
 105   return __fopen_internal (filename, mode, 1);
 106 }
 107
 108 #ifdef _LIBC
 109 strong_alias (_IO_new_fopen, __new_fopen)
 110 versioned_symbol (libc, _IO_new_fopen, _IO_fopen, GLIBC_2_1);
 111 versioned_symbol (libc, __new_fopen, fopen, GLIBC_2_1);
 112 #endif