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 unsigned char *old_p;
58 char *p;
59 struct __siov *iov;
60 int w, s;
61 char *nl;
62 int nlknown, nldist;
63
64 if (uio->uio_resid == 0)
65 return (0);
66 /* make sure we can write */
67 if (prepwrite(fp) != 0)
68 return (EOF);
69
70 #define MIN(a, b) ((a) < (b) ? (a) : (b))
71 #define COPY(n) (void)memcpy((void *)fp->_p, (void *)p, (size_t)(n))
72
73 iov = uio->uio_iov;
74 p = iov->iov_base;
75 len = iov->iov_len;
76 iov++;
77 #define GETIOV(extra_work) \
78 while (len == 0) { \
79 extra_work; \
80 p = iov->iov_base; \
81 len = iov->iov_len; \
82 iov++; \
83 }
84 if (fp->_flags & __SNBF) {
85 /*
86 * Unbuffered: write up to BUFSIZ bytes at a time.
87 */
88 do {
89 GETIOV(;);
90 w = _swrite(fp, p, MIN(len, BUFSIZ));
91 if (w <= 0)
92 goto err;
93 p += w;
94 len -= w;
95 } while ((uio->uio_resid -= w) != 0);
96 } else if ((fp->_flags & __SLBF) == 0) {
97 /*
98 * Fully buffered: fill partially full buffer, if any,
99 * and then flush. If there is no partial buffer, write
100 * one _bf._size byte chunk directly (without copying).
101 *
102 * String output is a special case: write as many bytes
103 * as fit, but pretend we wrote everything. This makes
104 * snprintf() return the number of bytes needed, rather
105 * than the number used, and avoids its write function
106 * (so that the write function can be invalid).
107 */
108 do {
109 GETIOV(;);
110 if ((fp->_flags & (__SALC | __SSTR)) ==
111 (__SALC | __SSTR) && fp->_w < len) {
112 size_t blen = fp->_p - fp->_bf._base;
113
114 /*
115 * Alloc an extra 128 bytes (+ 1 for NULL)
116 * so we don't call realloc(3) so often.
117 */
118 fp->_w = len + 128;
119 fp->_bf._size = blen + len + 128;
120 fp->_bf._base =
121 reallocf(fp->_bf._base, fp->_bf._size + 1);
122 if (fp->_bf._base == NULL)
123 goto err;
124 fp->_p = fp->_bf._base + blen;
125 }
126 w = fp->_w;
127 if (fp->_flags & __SSTR) {
128 if (len < w)
129 w = len;
130 if (w > 0) {
131 COPY(w); /* copy MIN(fp->_w,len), */
132 fp->_w -= w;
133 fp->_p += w;
134 }
135 w = len; /* but pretend copied all */
136 } else if (fp->_p > fp->_bf._base && len > w) {
137 /* fill and flush */
138 COPY(w);
139 /* fp->_w -= w; */ /* unneeded */
140 fp->_p += w;
141 old_p = fp->_p;
142 if (__fflush(fp) == EOF) {
143 if (old_p == fp->_p)
144 fp->_p -= w;
145 goto err;
146 }
147 } else if (len >= (w = fp->_bf._size)) {
148 /* write directly */
149 w = _swrite(fp, p, w);
150 if (w <= 0)
151 goto err;
152 } else {
153 /* fill and done */
154 w = len;
155 COPY(w);
156 fp->_w -= w;
157 fp->_p += w;
158 }
159 p += w;
160 len -= w;
161 } while ((uio->uio_resid -= w) != 0);
162 } else {
163 /*
164 * Line buffered: like fully buffered, but we
165 * must check for newlines. Compute the distance
166 * to the first newline (including the newline),
167 * or `infinity' if there is none, then pretend
168 * that the amount to write is MIN(len,nldist).
169 */
170 nlknown = 0;
171 nldist = 0; /* XXX just to keep gcc happy */
172 do {
173 GETIOV(nlknown = 0);
174 if (!nlknown) {
175 nl = memchr((void *)p, '\n', len);
176 nldist = nl ? nl + 1 - p : len + 1;
177 nlknown = 1;
178 }
179 s = MIN(len, nldist);
180 w = fp->_w + fp->_bf._size;
181 if (fp->_p > fp->_bf._base && s > w) {
182 COPY(w);
183 /* fp->_w -= w; */
184 fp->_p += w;
185 old_p = fp->_p;
186 if (__fflush(fp) == EOF) {
187 if (old_p == fp->_p)
188 fp->_p -= w;
189 goto err;
190 }
191 } else if (s >= (w = fp->_bf._size)) {
192 w = _swrite(fp, p, w);
193 if (w <= 0)
194 goto err;
195 } else {
196 w = s;
197 COPY(w);
198 fp->_w -= w;
199 fp->_p += w;
200 }
201 if ((nldist -= w) == 0) {
202 /* copied the newline: flush and forget */
203 if (__fflush(fp))
204 goto err;
205 nlknown = 0;
206 }
207 p += w;
208 len -= w;
209 } while ((uio->uio_resid -= w) != 0);
210 }
211 return (0);
212
213 err:
214 fp->_flags |= __SERR;
215 return (EOF);
216 }
217