1 /* $NetBSD: wsetup.c,v 1.12 2012/03/15 18:22:31 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Chris Torek. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include <sys/cdefs.h> 36 #if defined(LIBC_SCCS) && !defined(lint) 37 #if 0 38 static char sccsid[] = "@(#)wsetup.c 8.1 (Berkeley) 6/4/93"; 39 #else 40 __RCSID("$NetBSD: wsetup.c,v 1.12 2012/03/15 18:22:31 christos Exp $"); 41 #endif 42 #endif /* LIBC_SCCS and not lint */ 43 44 #include <assert.h> 45 #include <errno.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include "reentrant.h" 49 #include "local.h" 50 51 /* 52 * Various output routines call wsetup to be sure it is safe to write, 53 * because either _flags does not include __SWR, or _buf is NULL. 54 * _wsetup returns 0 if OK to write, nonzero otherwise. 55 */ 56 int 57 __swsetup(FILE *fp) 58 { 59 60 _DIAGASSERT(fp != NULL); 61 62 /* make sure stdio is set up */ 63 if (!__sdidinit) 64 __sinit(); 65 66 /* 67 * If we are not writing, we had better be reading and writing. 68 */ 69 if ((fp->_flags & __SWR) == 0) { 70 if ((fp->_flags & __SRW) == 0) 71 return EOF; 72 if (fp->_flags & __SRD) { 73 /* clobber any ungetc data */ 74 if (HASUB(fp)) 75 FREEUB(fp); 76 fp->_flags &= ~(__SRD|__SEOF); 77 fp->_r = 0; 78 fp->_p = fp->_bf._base; 79 } 80 fp->_flags |= __SWR; 81 } 82 83 /* 84 * Make a buffer if necessary, then set _w. 85 */ 86 if (fp->_bf._base == NULL) 87 __smakebuf(fp); 88 if (fp->_flags & __SLBF) { 89 /* 90 * It is line buffered, so make _lbfsize be -_bufsize 91 * for the putc() macro. We will change _lbfsize back 92 * to 0 whenever we turn off __SWR. 93 */ 94 fp->_w = 0; 95 fp->_lbfsize = -fp->_bf._size; 96 } else 97 fp->_w = fp->_flags & __SNBF ? 0 : fp->_bf._size; 98 return 0; 99 } 100