usr/src/lib/libc/port/stdio/_wrtchk.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*      Copyright (c) 1988 AT&T */
  28 /*        All Rights Reserved   */
  29
  30 #pragma ident   "%Z%%M% %I%     %E% SMI"
  31
  32 #include "lint.h"
  33 #include "file64.h"
  34 #include <stdio.h>
  35 #include <errno.h>
  36 #include <sys/types.h>
  37 #include "stdiom.h"
  38
  39 #undef _wrtchk
  40
  41 /* check permissions, correct for read & write changes */
  42 int
  43 _wrtchk(FILE *iop)
  44 {
  45         if ((iop->_flag & (_IOWRT | _IOEOF)) != _IOWRT) {
  46                 if (!(iop->_flag & (_IOWRT | _IORW))) {
  47                         iop->_flag |= _IOERR;
  48                         errno = EBADF;
  49                         return (EOF); /* stream is not writeable */
  50                 }
  51                 iop->_flag = (iop->_flag & ~_IOEOF) | _IOWRT;
  52         }
  53
  54         /* if first I/O to the stream get a buffer */
  55         if (iop->_base == NULL && _findbuf(iop) == NULL)
  56                 return (EOF);
  57         else if ((iop->_ptr == iop->_base) &&
  58             !(iop->_flag & (_IOLBF | _IONBF))) {
  59                 iop->_cnt = _bufend(iop) - iop->_ptr;
  60         }
  61         return (0);
  62 }