glibc-compat/oldiofdopen.c

   1 /* Copyright (C) 1993, 1994, 1997 Free Software Foundation, Inc.
   2    This file is part of the GNU IO Library.
   3
   4    This library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU General Public License as
   6    published by the Free Software Foundation; either version 2, or (at
   7    your option) any later version.
   8
   9    This library is distributed in the hope that it will be useful, but
  10    WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this library; see the file COPYING.  If not, write to
  16    the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
  17    MA 02111-1307, USA.
  18
  19    As a special exception, if you link this library with files
  20    compiled with a GNU compiler to produce an executable, this does
  21    not cause the resulting executable to be covered by the GNU General
  22    Public License.  This exception does not however invalidate any
  23    other reasons why the executable file might be covered by the GNU
  24    General Public License.  */
  25
  26 #define _IO_USE_OLD_IO_FILE
  27 #ifdef __STDC__
  28 # include <stdlib.h>
  29 #endif
  30 #include "libioP.h"
  31 #include <fcntl.h>
  32
  33 #ifndef _IO_fcntl
  34 # define _IO_fcntl __fcntl
  35 #endif
  36
  37 _IO_FILE *
  38 _IO_old_fdopen (fd, mode)
  39      int fd;
  40      const char *mode;
  41 {
  42   int read_write;
  43   int posix_mode = 0;
  44   struct locked_FILE
  45   {
  46     struct _IO_FILE_plus fp;
  47 #ifdef _IO_MTSAFE_IO
  48     _IO_lock_t lock;
  49 #endif
  50   } *new_f;
  51   int fd_flags;
  52
  53   switch (*mode++)
  54     {
  55     case 'r':
  56       read_write = _IO_NO_WRITES;
  57       break;
  58     case 'w':
  59       read_write = _IO_NO_READS;
  60       break;
  61     case 'a':
  62       posix_mode = O_APPEND;
  63       read_write = _IO_NO_READS|_IO_IS_APPENDING;
  64       break;
  65     default:
  66       MAYBE_SET_EINVAL;
  67       return NULL;
  68   }
  69   if (mode[0] == '+' || (mode[0] == 'b' && mode[1] == '+'))
  70     read_write &= _IO_IS_APPENDING;
  71 #ifdef F_GETFL
  72   fd_flags = _IO_fcntl (fd, F_GETFL);
  73 #ifndef O_ACCMODE
  74 #define O_ACCMODE (O_RDONLY|O_WRONLY|O_RDWR)
  75 #endif
  76   if (fd_flags == -1
  77       || ((fd_flags & O_ACCMODE) == O_RDONLY && !(read_write & _IO_NO_WRITES))
  78       || ((fd_flags & O_ACCMODE) == O_WRONLY && !(read_write & _IO_NO_READS)))
  79     return NULL;
  80
  81   /* The May 93 draft of P1003.4/D14.1 (redesignated as 1003.1b)
  82      [System Application Program Interface (API) Amendment 1:
  83      Realtime Extensions], Rationale B.8.3.3
  84      Open a Stream on a File Descriptor says:
  85
  86          Although not explicitly required by POSIX.1, a good
  87          implementation of append ("a") mode would cause the
  88          O_APPEND flag to be set.
  89
  90      (Historical implementations [such as Solaris2] do a one-time
  91      seek in fdopen.)
  92
  93      However, we do not turn O_APPEND off if the mode is "w" (even
  94      though that would seem consistent) because that would be more
  95      likely to break historical programs.
  96      */
  97   if ((posix_mode & O_APPEND) && !(fd_flags & O_APPEND))
  98     {
  99 #ifdef F_SETFL
 100       if (_IO_fcntl (fd, F_SETFL, fd_flags | O_APPEND) == -1)
 101 #endif
 102         return NULL;
 103     }
 104 #endif
 105
 106   new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
 107   if (new_f == NULL)
 108     return NULL;
 109 #ifdef _IO_MTSAFE_IO
 110   new_f->fp.file._lock = &new_f->lock;
 111 #endif
 112   _IO_init (&new_f->fp.file, 0);
 113   _IO_JUMPS (&new_f->fp) = &_IO_old_file_jumps;
 114   _IO_old_file_init (&new_f->fp.file);
 115 #if  !_IO_UNIFIED_JUMPTABLES
 116   new_f->fp.vtable = NULL;
 117 #endif
 118   if (_IO_old_file_attach (&new_f->fp.file, fd) == NULL)
 119     {
 120       _IO_un_link (&new_f->fp.file);
 121       free (new_f);
 122       return NULL;
 123     }
 124   new_f->fp.file._flags &= ~_IO_DELETE_DONT_CLOSE;
 125
 126   new_f->fp.file._IO_file_flags =
 127     _IO_mask_flags (&new_f->fp.file, read_write,
 128                     _IO_NO_READS+_IO_NO_WRITES+_IO_IS_APPENDING);
 129
 130   return (_IO_FILE *) &new_f->fp;
 131 }
 132
 133 #ifdef SHARED
 134 strong_alias (_IO_old_fdopen, __old_fdopen)
 135 symbol_version (_IO_old_fdopen, _IO_fdopen, GLIBC_2.0);
 136 symbol_version (__old_fdopen, fdopen, GLIBC_2.0);
 137 #else
 138 strong_alias (_IO_old_fdopen, _IO_fdopen);
 139 strong_alias (__old_fdopen, fdopen);
 140 #endif