1 /* $NetBSD: fvwrite.c,v 1.25 2012/03/27 15:05:42 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
38 static char sccsid[] = "@(#)fvwrite.c 8.1 (Berkeley) 6/4/93";
39 #else
40 __RCSID("$NetBSD: fvwrite.c,v 1.25 2012/03/27 15:05:42 christos Exp $");
41 #endif
42 #endif /* LIBC_SCCS and not lint */
43
44 #include <assert.h>
45 #include <stddef.h>
46 #include <errno.h>
47 #include <stdio.h>
48 #include <stdlib.h>
49 #include <string.h>
50 #include "reentrant.h"
51 #include "local.h"
52 #include "fvwrite.h"
53
54 /*
55 * Write some memory regions. Return zero on success, EOF on error.
56 *
57 * This routine is large and unsightly, but most of the ugliness due
58 * to the three different kinds of output buffering is handled here.
59 */
60 int
__sfvwrite(FILE * fp,struct __suio * uio)61 __sfvwrite(FILE *fp, struct __suio *uio)
62 {
63 size_t len;
64 char *p;
65 struct __siov *iov;
66 int s;
67 ssize_t w;
68 char *nl;
69 size_t nlknown, nldist;
70
71 _DIAGASSERT(fp != NULL);
72 _DIAGASSERT(uio != NULL);
73
74 if ((ssize_t)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, MIN(len, BUFSIZ));
107 if (w <= 0)
108 goto err;
109 p += w;
110 len -= w;
111 } while ((uio->uio_resid -= w) != 0);
112 } else if ((fp->_flags & __SLBF) == 0) {
113 /*
114 * Fully buffered: fill partially full buffer, if any,
115 * and then flush. If there is no partial buffer, write
116 * one _bf._size byte chunk directly (without copying).
117 *
118 * String output is a special case: write as many bytes
119 * as fit, but pretend we wrote everything. This makes
120 * snprintf() return the number of bytes needed, rather
121 * than the number used, and avoids its write function
122 * (so that the write function can be invalid).
123 */
124 do {
125 GETIOV(;);
126 if ((fp->_flags & (__SALC | __SSTR)) ==
127 (__SALC | __SSTR) && (size_t)fp->_w < len) {
128 ptrdiff_t blen = fp->_p - fp->_bf._base;
129 unsigned char *_base;
130 int _size;
131
132 /* Allocate space exponentially. */
133 _size = fp->_bf._size;
134 do {
135 _size = (_size << 1) + 1;
136 } while ((size_t)_size < blen + len);
137 _base = realloc(fp->_bf._base,
138 (size_t)(_size + 1));
139 if (_base == NULL)
140 goto err;
141 fp->_w += _size - fp->_bf._size;
142 fp->_bf._base = _base;
143 fp->_bf._size = _size;
144 fp->_p = _base + blen;
145 }
146 w = fp->_w;
147 if (fp->_flags & __SSTR) {
148 if (len < (size_t)w)
149 w = len;
150 COPY(w); /* copy MIN(fp->_w,len), */
151 fp->_w -= (int)w;
152 fp->_p += w;
153 w = len; /* but pretend copied all */
154 } else if (fp->_p > fp->_bf._base && len > (size_t)w) {
155 /* fill and flush */
156 COPY(w);
157 /* fp->_w -= w; */ /* unneeded */
158 fp->_p += w;
159 if (fflush(fp))
160 goto err;
161 } else if (len >= (size_t)(w = fp->_bf._size)) {
162 /* write directly */
163 w = (*fp->_write)(fp->_cookie, p, (size_t)w);
164 if (w <= 0)
165 goto err;
166 } else {
167 /* fill and done */
168 w = len;
169 COPY(w);
170 fp->_w -= (int)w;
171 fp->_p += w;
172 }
173 p += w;
174 len -= w;
175 } while ((uio->uio_resid -= w) != 0);
176 } else {
177 /*
178 * Line buffered: like fully buffered, but we
179 * must check for newlines. Compute the distance
180 * to the first newline (including the newline),
181 * or `infinity' if there is none, then pretend
182 * that the amount to write is MIN(len,nldist).
183 */
184 nlknown = 0;
185 nldist = 0; /* XXX just to keep gcc happy */
186 do {
187 GETIOV(nlknown = 0);
188 if (!nlknown) {
189 nl = memchr(p, '\n', len);
190 nldist = nl ? (size_t)(nl + 1 - p) : len + 1;
191 nlknown = 1;
192 }
193 s = (int)MIN(len, nldist);
194 w = fp->_w + fp->_bf._size;
195 if (fp->_p > fp->_bf._base && s > w) {
196 COPY(w);
197 /* fp->_w -= w; */
198 fp->_p += w;
199 if (fflush(fp))
200 goto err;
201 } else if (s >= (w = fp->_bf._size)) {
202 w = (*fp->_write)(fp->_cookie, p, (size_t)w);
203 if (w <= 0)
204 goto err;
205 } else {
206 w = s;
207 COPY(w);
208 fp->_w -= (int)w;
209 fp->_p += w;
210 }
211 if ((nldist -= w) == 0) {
212 /* copied the newline: flush and forget */
213 if (fflush(fp))
214 goto err;
215 nlknown = 0;
216 }
217 p += w;
218 len -= w;
219 } while ((uio->uio_resid -= w) != 0);
220 }
221 return 0;
222
223 err:
224 fp->_flags |= __SERR;
225 return EOF;
226 }
227