1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
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 #if defined(LIBC_SCCS) && !defined(lint)
36 static char sccsid[] = "@(#)fvwrite.c 8.1 (Berkeley) 6/4/93";
37 #endif /* LIBC_SCCS and not lint */
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
40
41 #include <stdio.h>
42 #include <stdlib.h>
43 #include <string.h>
44 #include "local.h"
45 #include "fvwrite.h"
46
47 /*
48 * Write some memory regions. Return zero on success, EOF on error.
49 *
50 * This routine is large and unsightly, but most of the ugliness due
51 * to the three different kinds of output buffering is handled here.
52 */
53 int
__sfvwrite(FILE * fp,struct __suio * uio)54 __sfvwrite(FILE *fp, struct __suio *uio)
55 {
56 size_t len;
57 char *p;
58 struct __siov *iov;
59 int w, s;
60 char *nl;
61 int nlknown, nldist;
62
63 if (uio->uio_resid == 0)
64 return (0);
65 /* make sure we can write */
66 if (prepwrite(fp) != 0)
67 return (EOF);
68
69 #define MIN(a, b) ((a) < (b) ? (a) : (b))
70 #define COPY(n) (void)memcpy((void *)fp->_p, (void *)p, (size_t)(n))
71
72 iov = uio->uio_iov;
73 p = iov->iov_base;
74 len = iov->iov_len;
75 iov++;
76 #define GETIOV(extra_work) \
77 while (len == 0) { \
78 extra_work; \
79 p = iov->iov_base; \
80 len = iov->iov_len; \
81 iov++; \
82 }
83 if (fp->_flags & __SNBF) {
84 /*
85 * Unbuffered: write up to BUFSIZ bytes at a time.
86 */
87 do {
88 GETIOV(;);
89 w = _swrite(fp, p, MIN(len, BUFSIZ));
90 if (w <= 0)
91 goto err;
92 p += w;
93 len -= w;
94 } while ((uio->uio_resid -= w) != 0);
95 } else if ((fp->_flags & __SLBF) == 0) {
96 /*
97 * Fully buffered: fill partially full buffer, if any,
98 * and then flush. If there is no partial buffer, write
99 * one _bf._size byte chunk directly (without copying).
100 *
101 * String output is a special case: write as many bytes
102 * as fit, but pretend we wrote everything. This makes
103 * snprintf() return the number of bytes needed, rather
104 * than the number used, and avoids its write function
105 * (so that the write function can be invalid).
106 */
107 do {
108 GETIOV(;);
109 if ((fp->_flags & (__SALC | __SSTR)) ==
110 (__SALC | __SSTR) && fp->_w < len) {
111 size_t blen = fp->_p - fp->_bf._base;
112
113 /*
114 * Alloc an extra 128 bytes (+ 1 for NULL)
115 * so we don't call realloc(3) so often.
116 */
117 fp->_w = len + 128;
118 fp->_bf._size = blen + len + 128;
119 fp->_bf._base =
120 reallocf(fp->_bf._base, fp->_bf._size + 1);
121 if (fp->_bf._base == NULL)
122 goto err;
123 fp->_p = fp->_bf._base + blen;
124 }
125 w = fp->_w;
126 if (fp->_flags & __SSTR) {
127 if (len < w)
128 w = len;
129 if (w > 0) {
130 COPY(w); /* copy MIN(fp->_w,len), */
131 fp->_w -= w;
132 fp->_p += w;
133 }
134 w = len; /* but pretend copied all */
135 } else if (fp->_p > fp->_bf._base && len > w) {
136 /* fill and flush */
137 COPY(w);
138 /* fp->_w -= w; */ /* unneeded */
139 fp->_p += w;
140 if (__fflush(fp))
141 goto err;
142 } else if (len >= (w = fp->_bf._size)) {
143 /* write directly */
144 w = _swrite(fp, p, w);
145 if (w <= 0)
146 goto err;
147 } else {
148 /* fill and done */
149 w = len;
150 COPY(w);
151 fp->_w -= w;
152 fp->_p += w;
153 }
154 p += w;
155 len -= w;
156 } while ((uio->uio_resid -= w) != 0);
157 } else {
158 /*
159 * Line buffered: like fully buffered, but we
160 * must check for newlines. Compute the distance
161 * to the first newline (including the newline),
162 * or `infinity' if there is none, then pretend
163 * that the amount to write is MIN(len,nldist).
164 */
165 nlknown = 0;
166 nldist = 0; /* XXX just to keep gcc happy */
167 do {
168 GETIOV(nlknown = 0);
169 if (!nlknown) {
170 nl = memchr((void *)p, '\n', len);
171 nldist = nl ? nl + 1 - p : len + 1;
172 nlknown = 1;
173 }
174 s = MIN(len, nldist);
175 w = fp->_w + fp->_bf._size;
176 if (fp->_p > fp->_bf._base && s > w) {
177 COPY(w);
178 /* fp->_w -= w; */
179 fp->_p += w;
180 if (__fflush(fp))
181 goto err;
182 } else if (s >= (w = fp->_bf._size)) {
183 w = _swrite(fp, p, w);
184 if (w <= 0)
185 goto err;
186 } else {
187 w = s;
188 COPY(w);
189 fp->_w -= w;
190 fp->_p += w;
191 }
192 if ((nldist -= w) == 0) {
193 /* copied the newline: flush and forget */
194 if (__fflush(fp))
195 goto err;
196 nlknown = 0;
197 }
198 p += w;
199 len -= w;
200 } while ((uio->uio_resid -= w) != 0);
201 }
202 return (0);
203
204 err:
205 fp->_flags |= __SERR;
206 return (EOF);
207 }
208