NetBSD/gnu/lib/libg++/libio/iofdopen.c

122 lines
3.5 KiB
C

/*
Copyright (C) 1993, 1994 Free Software Foundation
This file is part of the GNU IO Library. This library is free
software; you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the
Free Software Foundation; either version 2, or (at your option)
any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this library; see the file COPYING. If not, write to the Free
Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
As a special exception, if you link this library with files
compiled with a GNU compiler to produce an executable, this does not cause
the resulting executable to be covered by the GNU General Public License.
This exception does not however invalidate any other reasons why
the executable file might be covered by the GNU General Public License. */
#ifdef __STDC__
#include <stdlib.h>
#endif
#include "libioP.h"
#include <fcntl.h>
#ifndef _IO_fcntl
#define _IO_fcntl fcntl
#endif
_IO_FILE *
DEFUN(_IO_fdopen, (fd, mode),
int fd AND const char *mode)
{
int read_write;
int posix_mode = 0;
struct _IO_FILE_plus *fp;
int fd_flags;
switch (*mode++)
{
case 'r':
read_write = _IO_NO_WRITES;
break;
case 'w':
read_write = _IO_NO_READS;
break;
case 'a':
posix_mode = O_APPEND;
read_write = _IO_NO_READS|_IO_IS_APPENDING;
break;
default:
#ifdef EINVAL
errno = EINVAL;
#endif
return NULL;
}
if (mode[0] == '+' || (mode[0] == 'b' && mode[1] == '+'))
read_write &= _IO_IS_APPENDING;
#ifdef F_GETFL
fd_flags = _IO_fcntl (fd, F_GETFL);
#ifndef O_ACCMODE
#define O_ACCMODE (O_RDONLY|O_WRONLY|O_RDWR)
#endif
if (fd_flags == -1
|| ((fd_flags & O_ACCMODE) == O_RDONLY && !(read_write & _IO_NO_WRITES))
|| ((fd_flags & O_ACCMODE) == O_WRONLY && !(read_write & _IO_NO_READS)))
return NULL;
/* The May 93 draft of P1003.4/D14.1 (redesignated as 1003.1b)
[System Application Program Interface (API) Amendment 1:
Realtime Extensions], Rationale B.8.3.3
Open a Stream on a File Descriptor says:
Although not explicitly required by POSIX.1, a good
implementation of append ("a") mode would cause the
O_APPEND flag to be set.
(Historical implementations [such as Solaris2] do a one-time
seek in fdopen.)
However, we do not turn O_APPEND off if the mode is "w" (even
though that would seem consistent) because that would be more
likely to break historical programs.
*/
if ((posix_mode & O_APPEND) && !(fd_flags & O_APPEND))
{
#ifdef F_SETFL
if (_IO_fcntl (fd, F_SETFL, fd_flags | O_APPEND) == -1)
#endif
return NULL;
}
#endif
fp = (struct _IO_FILE_plus*)malloc(sizeof(struct _IO_FILE_plus));
if (fp == NULL)
return NULL;
_IO_init(&fp->file, 0);
_IO_JUMPS(&fp->file) = &_IO_file_jumps;
_IO_file_init(&fp->file);
#if !_IO_UNIFIED_JUMPTABLES
fp->vtable = NULL;
#endif
if (_IO_file_attach(&fp->file, fd) == NULL)
{
_IO_un_link(&fp->file);
free (fp);
return NULL;
}
fp->file._flags &= ~_IO_DELETE_DONT_CLOSE;
fp->file._IO_file_flags =
_IO_mask_flags(&fp->file, read_write,
_IO_NO_READS+_IO_NO_WRITES+_IO_IS_APPENDING);
return (_IO_FILE*)fp;
}