libio/iofdopen.c

   1 /* Copyright (C) 1993, 1994, 1997, 1998, 1999 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 #ifdef __STDC__
  27 #include <stdlib.h>
  28 #endif
  29 #include "libioP.h"
  30 #include <fcntl.h>
  31
  32 #ifndef _IO_fcntl
  33 #ifdef _LIBC
  34 #define _IO_fcntl __fcntl
  35 #else
  36 #define _IO_fcntl fcntl
  37 #endif
  38 #endif
  39
  40 _IO_FILE *
  41 _IO_new_fdopen (fd, mode)
  42      int fd;
  43      const char *mode;
  44 {
  45   int read_write;
  46   int posix_mode = 0;
  47   struct locked_FILE
  48   {
  49     struct _IO_FILE_plus fp;
  50 #ifdef _IO_MTSAFE_IO
  51     _IO_lock_t lock;
  52 #endif
  53     struct _IO_wide_data wd;
  54   } *new_f;
  55   int fd_flags;
  56
  57   switch (*mode++)
  58     {
  59     case 'r':
  60       read_write = _IO_NO_WRITES;
  61       break;
  62     case 'w':
  63       read_write = _IO_NO_READS;
  64       break;
  65     case 'a':
  66       posix_mode = O_APPEND;
  67       read_write = _IO_NO_READS|_IO_IS_APPENDING;
  68       break;
  69     default:
  70       MAYBE_SET_EINVAL;
  71       return NULL;
  72   }
  73   if (mode[0] == '+' || (mode[0] == 'b' && mode[1] == '+'))
  74     read_write &= _IO_IS_APPENDING;
  75 #ifdef F_GETFL
  76   fd_flags = _IO_fcntl (fd, F_GETFL);
  77 #ifndef O_ACCMODE
  78 #define O_ACCMODE (O_RDONLY|O_WRONLY|O_RDWR)
  79 #endif
  80   if (fd_flags == -1)
  81     return NULL;
  82
  83   if (((fd_flags & O_ACCMODE) == O_RDONLY && !(read_write & _IO_NO_WRITES))
  84       || ((fd_flags & O_ACCMODE) == O_WRONLY && !(read_write & _IO_NO_READS)))
  85     {
  86       MAYBE_SET_EINVAL;
  87       return NULL;
  88     }
  89
  90   /* The May 93 draft of P1003.4/D14.1 (redesignated as 1003.1b)
  91      [System Application Program Interface (API) Amendment 1:
  92      Realtime Extensions], Rationale B.8.3.3
  93      Open a Stream on a File Descriptor says:
  94
  95          Although not explicitly required by POSIX.1, a good
  96          implementation of append ("a") mode would cause the
  97          O_APPEND flag to be set.
  98
  99      (Historical implementations [such as Solaris2] do a one-time
 100      seek in fdopen.)
 101
 102      However, we do not turn O_APPEND off if the mode is "w" (even
 103      though that would seem consistent) because that would be more
 104      likely to break historical programs.
 105      */
 106   if ((posix_mode & O_APPEND) && !(fd_flags & O_APPEND))
 107     {
 108 #ifdef F_SETFL
 109       if (_IO_fcntl (fd, F_SETFL, fd_flags | O_APPEND) == -1)
 110 #endif
 111         return NULL;
 112     }
 113 #endif
 114
 115   new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
 116   if (new_f == NULL)
 117     return NULL;
 118 #ifdef _IO_MTSAFE_IO
 119   new_f->fp.file._lock = &new_f->lock;
 120 #endif
 121   _IO_no_init (&new_f->fp.file, 0, 0, &new_f->wd, &_IO_wfile_jumps);
 122   _IO_JUMPS (&new_f->fp) = &_IO_file_jumps;
 123   _IO_file_init (&new_f->fp.file);
 124 #if  !_IO_UNIFIED_JUMPTABLES
 125   new_f->fp.vtable = NULL;
 126 #endif
 127   if (_IO_file_attach (&new_f->fp.file, fd) == NULL)
 128     {
 129       _IO_un_link (&new_f->fp.file);
 130       free (new_f);
 131       return NULL;
 132     }
 133   new_f->fp.file._flags &= ~_IO_DELETE_DONT_CLOSE;
 134
 135   new_f->fp.file._IO_file_flags =
 136     _IO_mask_flags (&new_f->fp.file, read_write,
 137                     _IO_NO_READS+_IO_NO_WRITES+_IO_IS_APPENDING);
 138
 139   return &new_f->fp.file;
 140 }
 141
 142 #if defined PIC && DO_VERSIONING
 143 strong_alias (_IO_new_fdopen, __new_fdopen)
 144 default_symbol_version (_IO_new_fdopen, _IO_fdopen, GLIBC_2.1);
 145 default_symbol_version (__new_fdopen, fdopen, GLIBC_2.1);
 146 #else
 147 # ifdef weak_alias
 148 weak_alias (_IO_new_fdopen, _IO_fdopen)
 149 weak_alias (_IO_new_fdopen, fdopen)
 150 # endif
 151 #endif