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 */
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 ((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
201 err:
202 fp->_flags |= __SERR;
203 return (EOF);
204 }
205