lib/libc/stdio/wsetup.c

   1 /*-
   2  * Copyright (c) 1990, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Chris Torek.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 4. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  *
  32  * @(#)wsetup.c 8.1 (Berkeley) 6/4/93
  33  * $FreeBSD: src/lib/libc/stdio/wsetup.c,v 1.11 2009/01/08 06:38:06 das Exp $
  34  * $DragonFly: src/lib/libc/stdio/wsetup.c,v 1.5 2005/07/23 20:23:06 joerg Exp $
  35  */
  36
  37 #include <errno.h>
  38 #include <stdio.h>
  39 #include <stdlib.h>
  40 #include "local.h"
  41 #include "priv_stdio.h"
  42
  43 /*
  44  * Various output routines call wsetup to be sure it is safe to write,
  45  * because either _flags does not include __SWR, or _buf is NULL.
  46  * _wsetup returns 0 if OK to write; otherwise, it returns EOF and sets errno.
  47  */
  48 int
  49 __swsetup(FILE *fp)
  50 {
  51         /* make sure stdio is set up */
  52         if (!__sdidinit)
  53                 __sinit();
  54
  55         /*
  56          * If we are not writing, we had better be reading and writing.
  57          */
  58         if ((fp->pub._flags & __SWR) == 0) {
  59                 if ((fp->pub._flags & __SRW) == 0) {
  60                         errno = EBADF;
  61                         fp->pub._flags |= __SERR;
  62                         return (EOF);
  63                 }
  64                 if (fp->pub._flags & __SRD) {
  65                         /* clobber any ungetc data */
  66                         if (HASUB(fp))
  67                                 FREEUB(fp);
  68                         fp->pub._flags &= ~(__SRD|__SEOF);
  69                         fp->pub._r = 0;
  70                         fp->pub._p = fp->_bf._base;
  71                 }
  72                 fp->pub._flags |= __SWR;
  73         }
  74
  75         /*
  76          * Make a buffer if necessary, then set _w.
  77          */
  78         if (fp->_bf._base == NULL)
  79                 __smakebuf(fp);
  80         if (fp->pub._flags & __SLBF) {
  81                 /*
  82                  * It is line buffered, so make _lbfsize be -_bufsize
  83                  * for the putc() macro.  We will change _lbfsize back
  84                  * to 0 whenever we turn off __SWR.
  85                  */
  86                 fp->pub._w = 0;
  87                 fp->pub._lbfsize = -fp->_bf._size;
  88         } else
  89                 fp->pub._w = fp->pub._flags & __SNBF ? 0 : fp->_bf._size;
  90         return (0);
  91 }