1 /*-
2 * Copyright (c) 2013 Hudson River Trading LLC
3 * Written by: John H. Baldwin <jhb@FreeBSD.org>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
27 * $FreeBSD: head/lib/libc/stdio/open_memstream.c 281887 2015-04-23 14:22:20Z jhb $
28 */
29
30 #include "namespace.h"
31 #include <assert.h>
32 #include <errno.h>
33 #include <limits.h>
34 #include <stdio.h>
35 #include <stdlib.h>
36 #include <string.h>
37 #include <wchar.h>
38 #include "un-namespace.h"
39
40 /* XXX: There is no FPOS_MAX. This assumes fpos_t is an off_t. */
41 #define FPOS_MAX OFF_MAX
42
43 struct memstream {
44 char **bufp;
45 size_t *sizep;
46 ssize_t len;
47 fpos_t offset;
48 };
49
50 static int
memstream_grow(struct memstream * ms,fpos_t newoff)51 memstream_grow(struct memstream *ms, fpos_t newoff)
52 {
53 char *buf;
54 ssize_t newsize;
55
56 if (newoff < 0 || newoff >= SSIZE_MAX)
57 newsize = SSIZE_MAX - 1;
58 else
59 newsize = newoff;
60 if (newsize > ms->len) {
61 buf = realloc(*ms->bufp, newsize + 1);
62 if (buf != NULL) {
63 #ifdef DEBUG
64 fprintf(stderr, "MS: %p growing from %zd to %zd\n",
65 ms, ms->len, newsize);
66 #endif
67 memset(buf + ms->len + 1, 0, newsize - ms->len);
68 *ms->bufp = buf;
69 ms->len = newsize;
70 return (1);
71 }
72 return (0);
73 }
74 return (1);
75 }
76
77 static void
memstream_update(struct memstream * ms)78 memstream_update(struct memstream *ms)
79 {
80
81 assert(ms->len >= 0 && ms->offset >= 0);
82 *ms->sizep = ms->len < ms->offset ? ms->len : ms->offset;
83 }
84
85 static int
memstream_write(void * cookie,const char * buf,int len)86 memstream_write(void *cookie, const char *buf, int len)
87 {
88 struct memstream *ms;
89 ssize_t tocopy;
90
91 ms = cookie;
92 if (!memstream_grow(ms, ms->offset + len))
93 return (-1);
94 tocopy = ms->len - ms->offset;
95 if (len < tocopy)
96 tocopy = len;
97 memcpy(*ms->bufp + ms->offset, buf, tocopy);
98 ms->offset += tocopy;
99 memstream_update(ms);
100 #ifdef DEBUG
101 fprintf(stderr, "MS: write(%p, %d) = %zd\n", ms, len, tocopy);
102 #endif
103 return (tocopy);
104 }
105
106 static fpos_t
memstream_seek(void * cookie,fpos_t pos,int whence)107 memstream_seek(void *cookie, fpos_t pos, int whence)
108 {
109 struct memstream *ms;
110 #ifdef DEBUG
111 fpos_t old;
112 #endif
113
114 ms = cookie;
115 #ifdef DEBUG
116 old = ms->offset;
117 #endif
118 switch (whence) {
119 case SEEK_SET:
120 /* _fseeko() checks for negative offsets. */
121 assert(pos >= 0);
122 ms->offset = pos;
123 break;
124 case SEEK_CUR:
125 /* This is only called by _ftello(). */
126 assert(pos == 0);
127 break;
128 case SEEK_END:
129 if (pos < 0) {
130 if (pos + ms->len < 0) {
131 #ifdef DEBUG
132 fprintf(stderr,
133 "MS: bad SEEK_END: pos %jd, len %zd\n",
134 (intmax_t)pos, ms->len);
135 #endif
136 errno = EINVAL;
137 return (-1);
138 }
139 } else {
140 if (FPOS_MAX - ms->len < pos) {
141 #ifdef DEBUG
142 fprintf(stderr,
143 "MS: bad SEEK_END: pos %jd, len %zd\n",
144 (intmax_t)pos, ms->len);
145 #endif
146 errno = EOVERFLOW;
147 return (-1);
148 }
149 }
150 ms->offset = ms->len + pos;
151 break;
152 }
153 memstream_update(ms);
154 #ifdef DEBUG
155 fprintf(stderr, "MS: seek(%p, %jd, %d) %jd -> %jd\n", ms, (intmax_t)pos,
156 whence, (intmax_t)old, (intmax_t)ms->offset);
157 #endif
158 return (ms->offset);
159 }
160
161 static int
memstream_close(void * cookie)162 memstream_close(void *cookie)
163 {
164
165 free(cookie);
166 return (0);
167 }
168
169 FILE *
open_memstream(char ** bufp,size_t * sizep)170 open_memstream(char **bufp, size_t *sizep)
171 {
172 struct memstream *ms;
173 int save_errno;
174 FILE *fp;
175
176 if (bufp == NULL || sizep == NULL) {
177 errno = EINVAL;
178 return (NULL);
179 }
180 *bufp = calloc(1, 1);
181 if (*bufp == NULL)
182 return (NULL);
183 ms = malloc(sizeof(*ms));
184 if (ms == NULL) {
185 save_errno = errno;
186 free(*bufp);
187 *bufp = NULL;
188 errno = save_errno;
189 return (NULL);
190 }
191 ms->bufp = bufp;
192 ms->sizep = sizep;
193 ms->len = 0;
194 ms->offset = 0;
195 memstream_update(ms);
196 fp = funopen(ms, NULL, memstream_write, memstream_seek,
197 memstream_close);
198 if (fp == NULL) {
199 save_errno = errno;
200 free(ms);
201 free(*bufp);
202 *bufp = NULL;
203 errno = save_errno;
204 return (NULL);
205 }
206 fwide(fp, -1);
207 return (fp);
208 }
209