1/*	$NetBSD: fvwrite.c,v 1.21 2009/10/25 20:44:13 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
38static char sccsid[] = "@(#)fvwrite.c	8.1 (Berkeley) 6/4/93";
39#else
40__RCSID("$NetBSD: fvwrite.c,v 1.21 2009/10/25 20:44:13 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 <string.h>
49#include "reentrant.h"
50#include "local.h"
51#include "fvwrite.h"
52
53/*
54 * Write some memory regions.  Return zero on success, EOF on error.
55 *
56 * This routine is large and unsightly, but most of the ugliness due
57 * to the three different kinds of output buffering is handled here.
58 */
59int
60__sfvwrite(fp, uio)
61	FILE *fp;
62	struct __suio *uio;
63{
64	int len;
65	char *p;
66	struct __siov *iov;
67	int w, s;
68	char *nl;
69	int nlknown, nldist;
70
71	_DIAGASSERT(fp != NULL);
72	_DIAGASSERT(uio != NULL);
73
74	if ((int)uio->uio_resid < 0) {
75		errno = EINVAL;
76		return (EOF);
77	}
78	if (uio->uio_resid == 0)
79		return (0);
80	/* make sure we can write */
81	if (cantwrite(fp)) {
82		errno = EBADF;
83		return (EOF);
84	}
85
86#define	MIN(a, b) ((a) < (b) ? (a) : (b))
87#define	COPY(n)	  (void)memcpy(fp->_p, p, (size_t)(n))
88
89	iov = uio->uio_iov;
90	p = iov->iov_base;
91	len = iov->iov_len;
92	iov++;
93#define GETIOV(extra_work) \
94	while (len == 0) { \
95		extra_work; \
96		p = iov->iov_base; \
97		len = iov->iov_len; \
98		iov++; \
99	}
100	if (fp->_flags & __SNBF) {
101		/*
102		 * Unbuffered: write up to BUFSIZ bytes at a time.
103		 */
104		do {
105			GETIOV(;);
106			w = (*fp->_write)(fp->_cookie, p,
107			    (int)MIN(len, BUFSIZ));
108			if (w <= 0)
109				goto err;
110			p += w;
111			len -= w;
112		} while ((uio->uio_resid -= w) != 0);
113	} else if ((fp->_flags & __SLBF) == 0) {
114		/*
115		 * Fully buffered: fill partially full buffer, if any,
116		 * and then flush.  If there is no partial buffer, write
117		 * one _bf._size byte chunk directly (without copying).
118		 *
119		 * String output is a special case: write as many bytes
120		 * as fit, but pretend we wrote everything.  This makes
121		 * snprintf() return the number of bytes needed, rather
122		 * than the number used, and avoids its write function
123		 * (so that the write function can be invalid).
124		 */
125		do {
126			GETIOV(;);
127			if ((fp->_flags & (__SALC | __SSTR)) ==
128			    (__SALC | __SSTR) && fp->_w < len) {
129				int blen = fp->_p - fp->_bf._base;
130				unsigned char *_base;
131				int _size;
132
133				/* Allocate space exponentially. */
134				_size = fp->_bf._size;
135				do {
136					_size = (_size << 1) + 1;
137				} while (_size < blen + len);
138				_base = realloc(fp->_bf._base,
139				    (size_t)(_size + 1));
140				if (_base == NULL)
141					goto err;
142				fp->_w += _size - fp->_bf._size;
143				fp->_bf._base = _base;
144				fp->_bf._size = _size;
145				fp->_p = _base + blen;
146			}
147			w = fp->_w;
148			if (fp->_flags & __SSTR) {
149				if (len < w)
150					w = len;
151				COPY(w);	/* copy MIN(fp->_w,len), */
152				fp->_w -= w;
153				fp->_p += w;
154				w = len;	/* but pretend copied all */
155			} else if (fp->_p > fp->_bf._base && len > w) {
156				/* fill and flush */
157				COPY(w);
158				/* fp->_w -= w; */ /* unneeded */
159				fp->_p += w;
160				if (fflush(fp))
161					goto err;
162			} else if (len >= (w = fp->_bf._size)) {
163				/* write directly */
164				w = (*fp->_write)(fp->_cookie, p, w);
165				if (w <= 0)
166					goto err;
167			} else {
168				/* fill and done */
169				w = len;
170				COPY(w);
171				fp->_w -= w;
172				fp->_p += w;
173			}
174			p += w;
175			len -= w;
176		} while ((uio->uio_resid -= w) != 0);
177	} else {
178		/*
179		 * Line buffered: like fully buffered, but we
180		 * must check for newlines.  Compute the distance
181		 * to the first newline (including the newline),
182		 * or `infinity' if there is none, then pretend
183		 * that the amount to write is MIN(len,nldist).
184		 */
185		nlknown = 0;
186		nldist = 0;	/* XXX just to keep gcc happy */
187		do {
188			GETIOV(nlknown = 0);
189			if (!nlknown) {
190				nl = memchr(p, '\n', (size_t)len);
191				nldist = nl ? nl + 1 - p : len + 1;
192				nlknown = 1;
193			}
194			s = MIN(len, nldist);
195			w = fp->_w + fp->_bf._size;
196			if (fp->_p > fp->_bf._base && s > w) {
197				COPY(w);
198				/* fp->_w -= w; */
199				fp->_p += w;
200				if (fflush(fp))
201					goto err;
202			} else if (s >= (w = fp->_bf._size)) {
203				w = (*fp->_write)(fp->_cookie, p, w);
204				if (w <= 0)
205				 	goto err;
206			} else {
207				w = s;
208				COPY(w);
209				fp->_w -= w;
210				fp->_p += w;
211			}
212			if ((nldist -= w) == 0) {
213				/* copied the newline: flush and forget */
214				if (fflush(fp))
215					goto err;
216				nlknown = 0;
217			}
218			p += w;
219			len -= w;
220		} while ((uio->uio_resid -= w) != 0);
221	}
222	return (0);
223
224err:
225	fp->_flags |= __SERR;
226	return (EOF);
227}
228