1/*	$OpenBSD: fvwrite.c,v 1.17 2009/11/09 00:18:27 kurt 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 <stdio.h>
35#include <stdlib.h>
36#include <string.h>
37#include <errno.h>
38#include "local.h"
39#include "fvwrite.h"
40
41/*
42 * Write some memory regions.  Return zero on success, EOF on error.
43 *
44 * This routine is large and unsightly, but most of the ugliness due
45 * to the three different kinds of output buffering is handled here.
46 */
47int
48__sfvwrite(FILE *fp, struct __suio *uio)
49{
50	size_t len;
51	char *p;
52	struct __siov *iov;
53	int w, s;
54	char *nl;
55	int nlknown, nldist;
56
57	if ((len = uio->uio_resid) == 0)
58		return (0);
59	/* make sure we can write */
60	if (cantwrite(fp)) {
61		errno = EBADF;
62		return (EOF);
63	}
64
65#define	MIN(a, b) ((a) < (b) ? (a) : (b))
66#define	COPY(n)	  (void)memcpy((void *)fp->_p, (void *)p, (size_t)(n))
67
68	iov = uio->uio_iov;
69	p = iov->iov_base;
70	len = iov->iov_len;
71	iov++;
72#define GETIOV(extra_work) \
73	while (len == 0) { \
74		extra_work; \
75		p = iov->iov_base; \
76		len = iov->iov_len; \
77		iov++; \
78	}
79	if (fp->_flags & __SNBF) {
80		/*
81		 * Unbuffered: write up to BUFSIZ bytes at a time.
82		 */
83		do {
84			GETIOV(;);
85			w = (*fp->_write)(fp->_cookie, p, MIN(len, BUFSIZ));
86			if (w <= 0)
87				goto err;
88			p += w;
89			len -= w;
90		} while ((uio->uio_resid -= w) != 0);
91	} else if ((fp->_flags & __SLBF) == 0) {
92		/*
93		 * Fully buffered: fill partially full buffer, if any,
94		 * and then flush.  If there is no partial buffer, write
95		 * one _bf._size byte chunk directly (without copying).
96		 *
97		 * String output is a special case: write as many bytes
98		 * as fit, but pretend we wrote everything.  This makes
99		 * snprintf() return the number of bytes needed, rather
100		 * than the number used, and avoids its write function
101		 * (so that the write function can be invalid).
102		 */
103		do {
104			GETIOV(;);
105			if ((fp->_flags & (__SALC | __SSTR)) ==
106			    (__SALC | __SSTR) && fp->_w < len) {
107				size_t blen = fp->_p - fp->_bf._base;
108				unsigned char *_base;
109				int _size;
110
111				/* Allocate space exponentially. */
112				_size = fp->_bf._size;
113				do {
114					_size = (_size << 1) + 1;
115				} while (_size < blen + len);
116				_base = realloc(fp->_bf._base, _size + 1);
117				if (_base == NULL)
118					goto err;
119				fp->_w += _size - fp->_bf._size;
120				fp->_bf._base = _base;
121				fp->_bf._size = _size;
122				fp->_p = _base + blen;
123			}
124			w = fp->_w;
125			if (fp->_flags & __SSTR) {
126				if (len < w)
127					w = len;
128				COPY(w);	/* copy MIN(fp->_w,len), */
129				fp->_w -= w;
130				fp->_p += w;
131				w = len;	/* but pretend copied all */
132			} else if (fp->_p > fp->_bf._base && len > w) {
133				/* fill and flush */
134				COPY(w);
135				/* fp->_w -= w; */ /* unneeded */
136				fp->_p += w;
137				if (__sflush(fp))
138					goto err;
139			} else if (len >= (w = fp->_bf._size)) {
140				/* write directly */
141				w = (*fp->_write)(fp->_cookie, p, w);
142				if (w <= 0)
143					goto err;
144			} else {
145				/* fill and done */
146				w = len;
147				COPY(w);
148				fp->_w -= w;
149				fp->_p += w;
150			}
151			p += w;
152			len -= w;
153		} while ((uio->uio_resid -= w) != 0);
154	} else {
155		/*
156		 * Line buffered: like fully buffered, but we
157		 * must check for newlines.  Compute the distance
158		 * to the first newline (including the newline),
159		 * or `infinity' if there is none, then pretend
160		 * that the amount to write is MIN(len,nldist).
161		 */
162		nlknown = 0;
163		nldist = 0;	/* XXX just to keep gcc happy */
164		do {
165			GETIOV(nlknown = 0);
166			if (!nlknown) {
167				nl = memchr((void *)p, '\n', len);
168				nldist = nl ? nl + 1 - p : len + 1;
169				nlknown = 1;
170			}
171			s = MIN(len, nldist);
172			w = fp->_w + fp->_bf._size;
173			if (fp->_p > fp->_bf._base && s > w) {
174				COPY(w);
175				/* fp->_w -= w; */
176				fp->_p += w;
177				if (__sflush(fp))
178					goto err;
179			} else if (s >= (w = fp->_bf._size)) {
180				w = (*fp->_write)(fp->_cookie, p, w);
181				if (w <= 0)
182				 	goto err;
183			} else {
184				w = s;
185				COPY(w);
186				fp->_w -= w;
187				fp->_p += w;
188			}
189			if ((nldist -= w) == 0) {
190				/* copied the newline: flush and forget */
191				if (__sflush(fp))
192					goto err;
193				nlknown = 0;
194			}
195			p += w;
196			len -= w;
197		} while ((uio->uio_resid -= w) != 0);
198	}
199	return (0);
200
201err:
202	fp->_flags |= __SERR;
203	return (EOF);
204}
205