1 /* $OpenBSD: wsetup.c,v 1.8 2023/10/06 16:41:02 millert Exp $ */ 2 /*- 3 * Copyright (c) 1990, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * Chris Torek. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #include <errno.h> 35 #include <stdio.h> 36 #include <stdlib.h> 37 #include "local.h" 38 39 /* 40 * Various output routines call wsetup to be sure it is safe to write, 41 * because either _flags does not include __SWR, or _buf is NULL. 42 * __swsetup returns 0 if OK to write, nonzero otherwise, setting errno. 43 */ 44 int 45 __swsetup(FILE *fp) 46 { 47 /* make sure stdio is set up */ 48 if (!__sdidinit) 49 __sinit(); 50 51 /* 52 * If we are not writing, we had better be reading and writing. 53 */ 54 if ((fp->_flags & __SWR) == 0) { 55 if ((fp->_flags & __SRW) == 0) { 56 errno = EBADF; 57 fp->_flags |= __SERR; 58 return (EOF); 59 } 60 if (fp->_flags & __SRD) { 61 /* clobber any ungetc data */ 62 if (HASUB(fp)) 63 FREEUB(fp); 64 fp->_flags &= ~(__SRD|__SEOF); 65 fp->_r = 0; 66 fp->_p = fp->_bf._base; 67 } 68 fp->_flags |= __SWR; 69 } 70 71 /* 72 * Make a buffer if necessary, then set _w. 73 */ 74 if (fp->_bf._base == NULL) { 75 if ((fp->_flags & (__SSTR | __SALC)) == __SSTR) { 76 errno = EINVAL; 77 fp->_flags |= __SERR; 78 return (EOF); 79 } 80 __smakebuf(fp); 81 } 82 if (fp->_flags & __SLBF) { 83 /* 84 * It is line buffered, so make _lbfsize be -_bufsize 85 * for the putc() macro. We will change _lbfsize back 86 * to 0 whenever we turn off __SWR. 87 */ 88 fp->_w = 0; 89 fp->_lbfsize = -fp->_bf._size; 90 } else 91 fp->_w = fp->_flags & __SNBF ? 0 : fp->_bf._size; 92 return (0); 93 } 94