libio/iofdopen.c

   1 /* Copyright (C) 1993, 1994, 1997-1999, 2000 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 #ifdef _LIBC
  33 # include <shlib-compat.h>
  34 #endif
  35
  36 #ifndef _IO_fcntl
  37 #ifdef _LIBC
  38 #define _IO_fcntl __fcntl
  39 #else
  40 #define _IO_fcntl fcntl
  41 #endif
  42 #endif
  43
  44 _IO_FILE *
  45 _IO_new_fdopen (fd, mode)
  46      int fd;
  47      const char *mode;
  48 {
  49   int read_write;
  50   int posix_mode = 0;
  51   struct locked_FILE
  52   {
  53     struct _IO_FILE_plus fp;
  54 #ifdef _IO_MTSAFE_IO
  55     _IO_lock_t lock;
  56 #endif
  57     struct _IO_wide_data wd;
  58   } *new_f;
  59   int fd_flags;
  60
  61   switch (*mode++)
  62     {
  63     case 'r':
  64       read_write = _IO_NO_WRITES;
  65       break;
  66     case 'w':
  67       read_write = _IO_NO_READS;
  68       break;
  69     case 'a':
  70       posix_mode = O_APPEND;
  71       read_write = _IO_NO_READS|_IO_IS_APPENDING;
  72       break;
  73     default:
  74       MAYBE_SET_EINVAL;
  75       return NULL;
  76   }
  77   if (mode[0] == '+' || (mode[0] == 'b' && mode[1] == '+'))
  78     read_write &= _IO_IS_APPENDING;
  79 #ifdef F_GETFL
  80   fd_flags = _IO_fcntl (fd, F_GETFL);
  81 #ifndef O_ACCMODE
  82 #define O_ACCMODE (O_RDONLY|O_WRONLY|O_RDWR)
  83 #endif
  84   if (fd_flags == -1)
  85     return NULL;
  86
  87   if (((fd_flags & O_ACCMODE) == O_RDONLY && !(read_write & _IO_NO_WRITES))
  88       || ((fd_flags & O_ACCMODE) == O_WRONLY && !(read_write & _IO_NO_READS)))
  89     {
  90       MAYBE_SET_EINVAL;
  91       return NULL;
  92     }
  93
  94   /* The May 93 draft of P1003.4/D14.1 (redesignated as 1003.1b)
  95      [System Application Program Interface (API) Amendment 1:
  96      Realtime Extensions], Rationale B.8.3.3
  97      Open a Stream on a File Descriptor says:
  98
  99          Although not explicitly required by POSIX.1, a good
 100          implementation of append ("a") mode would cause the
 101          O_APPEND flag to be set.
 102
 103      (Historical implementations [such as Solaris2] do a one-time
 104      seek in fdopen.)
 105
 106      However, we do not turn O_APPEND off if the mode is "w" (even
 107      though that would seem consistent) because that would be more
 108      likely to break historical programs.
 109      */
 110   if ((posix_mode & O_APPEND) && !(fd_flags & O_APPEND))
 111     {
 112 #ifdef F_SETFL
 113       if (_IO_fcntl (fd, F_SETFL, fd_flags | O_APPEND) == -1)
 114 #endif
 115         return NULL;
 116     }
 117 #endif
 118
 119   new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
 120   if (new_f == NULL)
 121     return NULL;
 122 #ifdef _IO_MTSAFE_IO
 123   new_f->fp.file._lock = &new_f->lock;
 124 #endif
 125   _IO_no_init (&new_f->fp.file, 0, 0, &new_f->wd, &_IO_wfile_jumps);
 126   _IO_JUMPS (&new_f->fp) = &_IO_file_jumps;
 127   _IO_file_init (&new_f->fp);
 128 #if  !_IO_UNIFIED_JUMPTABLES
 129   new_f->fp.vtable = NULL;
 130 #endif
 131   if (_IO_file_attach ((_IO_FILE *) &new_f->fp, fd) == NULL)
 132     {
 133       _IO_un_link (&new_f->fp);
 134       free (new_f);
 135       return NULL;
 136     }
 137   new_f->fp.file._flags &= ~_IO_DELETE_DONT_CLOSE;
 138
 139   new_f->fp.file._IO_file_flags =
 140     _IO_mask_flags (&new_f->fp.file, read_write,
 141                     _IO_NO_READS+_IO_NO_WRITES+_IO_IS_APPENDING);
 142
 143   return (_IO_FILE *) &new_f->fp;
 144 }
 145
 146 strong_alias (_IO_new_fdopen, __new_fdopen)
 147 versioned_symbol (libc, _IO_new_fdopen, _IO_fdopen, GLIBC_2_1);
 148 versioned_symbol (libc, __new_fdopen, fdopen, GLIBC_2_1);