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 <stdio.h>
39 #include <stdlib.h>
40 #include <string.h>
41 #include "local.h"
42 #include "fvwrite.h"
43
44 /*
45 * Write some memory regions. Return zero on success, EOF on error.
46 *
47 * This routine is large and unsightly, but most of the ugliness due
48 * to the three different kinds of output buffering is handled here.
49 */
50 int
__sfvwrite(FILE * fp,struct __suio * uio)51 __sfvwrite(FILE *fp, struct __suio *uio)
52 {
53 size_t len;
54 char *p;
55 struct __siov *iov;
56 int w, s;
57 char *nl;
58 int nlknown, nldist;
59
60 if (uio->uio_resid == 0)
61 return (0);
62 /* make sure we can write */
63 if (prepwrite(fp) != 0)
64 return (EOF);
65
66 #define MIN(a, b) ((a) < (b) ? (a) : (b))
67 #define COPY(n) (void)memcpy((void *)fp->_p, (void *)p, (size_t)(n))
68
69 iov = uio->uio_iov;
70 p = iov->iov_base;
71 len = iov->iov_len;
72 iov++;
73 #define GETIOV(extra_work) \
74 while (len == 0) { \
75 extra_work; \
76 p = iov->iov_base; \
77 len = iov->iov_len; \
78 iov++; \
79 }
80 if (fp->_flags & __SNBF) {
81 /*
82 * Unbuffered: write up to BUFSIZ bytes at a time.
83 */
84 do {
85 GETIOV(;);
86 w = _swrite(fp, p, MIN(len, BUFSIZ));
87 if (w <= 0)
88 goto err;
89 p += w;
90 len -= w;
91 } while ((uio->uio_resid -= w) != 0);
92 } else if ((fp->_flags & __SLBF) == 0) {
93 /*
94 * Fully buffered: fill partially full buffer, if any,
95 * and then flush. If there is no partial buffer, write
96 * one _bf._size byte chunk directly (without copying).
97 *
98 * String output is a special case: write as many bytes
99 * as fit, but pretend we wrote everything. This makes
100 * snprintf() return the number of bytes needed, rather
101 * than the number used, and avoids its write function
102 * (so that the write function can be invalid).
103 */
104 do {
105 GETIOV(;);
106 if ((fp->_flags & (__SALC | __SSTR)) ==
107 (__SALC | __SSTR) && fp->_w < len) {
108 size_t blen = fp->_p - fp->_bf._base;
109
110 /*
111 * Alloc an extra 128 bytes (+ 1 for NULL)
112 * so we don't call realloc(3) so often.
113 */
114 fp->_w = len + 128;
115 fp->_bf._size = blen + len + 128;
116 fp->_bf._base =
117 reallocf(fp->_bf._base, fp->_bf._size + 1);
118 if (fp->_bf._base == NULL)
119 goto err;
120 fp->_p = fp->_bf._base + blen;
121 }
122 w = fp->_w;
123 if (fp->_flags & __SSTR) {
124 if (len < w)
125 w = len;
126 if (w > 0) {
127 COPY(w); /* copy MIN(fp->_w,len), */
128 fp->_w -= w;
129 fp->_p += w;
130 }
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 (__fflush(fp))
138 goto err;
139 } else if (len >= (w = fp->_bf._size)) {
140 /* write directly */
141 w = _swrite(fp, 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 (__fflush(fp))
178 goto err;
179 } else if (s >= (w = fp->_bf._size)) {
180 w = _swrite(fp, 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 (__fflush(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