stdio/FreeBSD/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
  33 #if defined(LIBC_SCCS) && !defined(lint)
  34 static char sccsid[] = "@(#)wsetup.c    8.1 (Berkeley) 6/4/93";
  35 #endif /* LIBC_SCCS and not lint */
  36 #include <sys/cdefs.h>
  37 __FBSDID("$FreeBSD: src/lib/libc/stdio/wsetup.c,v 1.11 2009/01/08 06:38:06 das Exp $");
  38
  39 #include <errno.h>
  40 #include <stdio.h>
  41 #include <stdlib.h>
  42 #include "local.h"
  43
  44 /*
  45  * Various output routines call wsetup to be sure it is safe to write,
  46  * because either _flags does not include __SWR, or _buf is NULL.
  47  * _wsetup returns 0 if OK to write; otherwise, it returns EOF and sets errno.
  48  */
  49 int
  50 __swsetup(fp)
  51         FILE *fp;
  52 {
  53         /* make sure stdio is set up */
  54         pthread_once(&__sdidinit, __sinit);
  55
  56         /*
  57          * If we are not writing, we had better be reading and writing.
  58          */
  59         if ((fp->_flags & __SWR) == 0) {
  60                 if ((fp->_flags & __SRW) == 0) {
  61                         errno = EBADF;
  62                         fp->_flags |= __SERR;
  63                         return (EOF);
  64                 }
  65                 if (fp->_flags & __SRD) {
  66                         /* clobber any ungetc data */
  67                         if (HASUB(fp))
  68                                 FREEUB(fp);
  69                         fp->_flags &= ~(__SRD|__SEOF);
  70                         fp->_r = 0;
  71                         fp->_p = fp->_bf._base;
  72                 }
  73                 fp->_flags |= __SWR;
  74         }
  75
  76         /*
  77          * Make a buffer if necessary, then set _w.
  78          */
  79         if (fp->_bf._base == NULL)
  80                 __smakebuf(fp);
  81         if (fp->_flags & __SLBF) {
  82                 /*
  83                  * It is line buffered, so make _lbfsize be -_bufsize
  84                  * for the putc() macro.  We will change _lbfsize back
  85                  * to 0 whenever we turn off __SWR.
  86                  */
  87                 fp->_w = 0;
  88                 fp->_lbfsize = -fp->_bf._size;
  89         } else
  90                 fp->_w = fp->_flags & __SNBF ? 0 : fp->_bf._size;
  91         return (0);
  92 }