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 * 3. 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 * @(#)fvwrite.c 8.1 (Berkeley) 6/4/93
33 * $FreeBSD: head/lib/libc/stdio/fvwrite.c 249810 2013-04-23 14:36:44Z emaste $
34 */
35
36 #include <stdio.h>
37 #include <stdlib.h>
38 #include <string.h>
39 #include "local.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 */
47 int
__sfvwrite(FILE * fp,struct __suio * uio)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 (uio->uio_resid == 0)
58 return (0);
59 /* make sure we can write */
60 if (prepwrite(fp) != 0)
61 return (EOF);
62
63 #define MIN(a, b) ((a) < (b) ? (a) : (b))
64 #define COPY(n) (void)memcpy((void *)fp->pub._p, (void *)p, (size_t)(n))
65
66 iov = uio->uio_iov;
67 p = iov->iov_base;
68 len = iov->iov_len;
69 iov++;
70 #define GETIOV(extra_work) \
71 while (len == 0) { \
72 extra_work; \
73 p = iov->iov_base; \
74 len = iov->iov_len; \
75 iov++; \
76 }
77 if (fp->pub._flags & __SNBF) {
78 /*
79 * Unbuffered: write up to BUFSIZ bytes at a time.
80 */
81 do {
82 GETIOV(;);
83 w = _swrite(fp, p, MIN(len, BUFSIZ));
84 if (w <= 0)
85 goto err;
86 p += w;
87 len -= w;
88 } while ((uio->uio_resid -= w) != 0);
89 } else if ((fp->pub._flags & __SLBF) == 0) {
90 /*
91 * Fully buffered: fill partially full buffer, if any,
92 * and then flush. If there is no partial buffer, write
93 * one _bf._size byte chunk directly (without copying).
94 *
95 * String output is a special case: write as many bytes
96 * as fit, but pretend we wrote everything. This makes
97 * snprintf() return the number of bytes needed, rather
98 * than the number used, and avoids its write function
99 * (so that the write function can be invalid).
100 */
101 do {
102 GETIOV(;);
103 if ((fp->pub._flags & (__SALC | __SSTR)) ==
104 (__SALC | __SSTR) && fp->pub._w < len) {
105 size_t blen = fp->pub._p - fp->_bf._base;
106
107 /*
108 * Alloc an extra 128 bytes (+ 1 for NULL)
109 * so we don't call realloc(3) so often.
110 */
111 fp->pub._w = len + 128;
112 fp->_bf._size = blen + len + 128;
113 fp->_bf._base =
114 reallocf(fp->_bf._base, fp->_bf._size + 1);
115 if (fp->_bf._base == NULL)
116 goto err;
117 fp->pub._p = fp->_bf._base + blen;
118 }
119 w = fp->pub._w;
120 if (fp->pub._flags & __SSTR) {
121 if (len < w)
122 w = len;
123 if (w > 0) {
124 COPY(w); /* copy MIN(fp->pub._w,len), */
125 fp->pub._w -= w;
126 fp->pub._p += w;
127 }
128 w = len; /* but pretend copied all */
129 } else if (fp->pub._p > fp->_bf._base && len > w) {
130 /* fill and flush */
131 COPY(w);
132 /* fp->pub._w -= w; */ /* unneeded */
133 fp->pub._p += w;
134 if (__fflush(fp))
135 goto err;
136 } else if (len >= (w = fp->_bf._size)) {
137 /* write directly */
138 w = _swrite(fp, p, w);
139 if (w <= 0)
140 goto err;
141 } else {
142 /* fill and done */
143 w = len;
144 COPY(w);
145 fp->pub._w -= w;
146 fp->pub._p += w;
147 }
148 p += w;
149 len -= w;
150 } while ((uio->uio_resid -= w) != 0);
151 } else {
152 /*
153 * Line buffered: like fully buffered, but we
154 * must check for newlines. Compute the distance
155 * to the first newline (including the newline),
156 * or `infinity' if there is none, then pretend
157 * that the amount to write is MIN(len,nldist).
158 */
159 nlknown = 0;
160 nldist = 0; /* XXX just to keep gcc happy */
161 do {
162 GETIOV(nlknown = 0);
163 if (!nlknown) {
164 nl = memchr((void *)p, '\n', len);
165 nldist = nl ? nl + 1 - p : len + 1;
166 nlknown = 1;
167 }
168 s = MIN(len, nldist);
169 w = fp->pub._w + fp->_bf._size;
170 if (fp->pub._p > fp->_bf._base && s > w) {
171 COPY(w);
172 /* fp->pub._w -= w; */
173 fp->pub._p += w;
174 if (__fflush(fp))
175 goto err;
176 } else if (s >= (w = fp->_bf._size)) {
177 w = _swrite(fp, p, w);
178 if (w <= 0)
179 goto err;
180 } else {
181 w = s;
182 COPY(w);
183 fp->pub._w -= w;
184 fp->pub._p += w;
185 }
186 if ((nldist -= w) == 0) {
187 /* copied the newline: flush and forget */
188 if (__fflush(fp))
189 goto err;
190 nlknown = 0;
191 }
192 p += w;
193 len -= w;
194 } while ((uio->uio_resid -= w) != 0);
195 }
196 return (0);
197
198 err:
199 fp->pub._flags |= __SERR;
200 return (EOF);
201 }
202