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
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD$");
30
31 #include "namespace.h"
32 #include <assert.h>
33 #include <errno.h>
34 #include <limits.h>
35 #ifdef DEBUG
36 #include <stdint.h>
37 #endif
38 #include <stdio.h>
39 #include <stdlib.h>
40 #include <string.h>
41 #include <wchar.h>
42 #include "un-namespace.h"
43
44 /* XXX: There is no FPOS_MAX. This assumes fpos_t is an off_t. */
45 #define FPOS_MAX OFF_MAX
46
47 struct memstream {
48 char **bufp;
49 size_t *sizep;
50 ssize_t len;
51 fpos_t offset;
52 };
53
54 static int
memstream_grow(struct memstream * ms,fpos_t newoff)55 memstream_grow(struct memstream *ms, fpos_t newoff)
56 {
57 char *buf;
58 ssize_t newsize;
59
60 if (newoff < 0 || newoff >= SSIZE_MAX)
61 newsize = SSIZE_MAX - 1;
62 else
63 newsize = newoff;
64 if (newsize > ms->len) {
65 buf = realloc(*ms->bufp, newsize + 1);
66 if (buf != NULL) {
67 #ifdef DEBUG
68 fprintf(stderr, "MS: %p growing from %zd to %zd\n",
69 ms, ms->len, newsize);
70 #endif
71 memset(buf + ms->len + 1, 0, newsize - ms->len);
72 *ms->bufp = buf;
73 ms->len = newsize;
74 return (1);
75 }
76 return (0);
77 }
78 return (1);
79 }
80
81 static void
memstream_update(struct memstream * ms)82 memstream_update(struct memstream *ms)
83 {
84
85 assert(ms->len >= 0 && ms->offset >= 0);
86 *ms->sizep = ms->len < ms->offset ? ms->len : ms->offset;
87 }
88
89 static int
memstream_write(void * cookie,const char * buf,int len)90 memstream_write(void *cookie, const char *buf, int len)
91 {
92 struct memstream *ms;
93 ssize_t tocopy;
94
95 ms = cookie;
96 if (!memstream_grow(ms, ms->offset + len))
97 return (-1);
98 tocopy = ms->len - ms->offset;
99 if (len < tocopy)
100 tocopy = len;
101 memcpy(*ms->bufp + ms->offset, buf, tocopy);
102 ms->offset += tocopy;
103 memstream_update(ms);
104 #ifdef DEBUG
105 fprintf(stderr, "MS: write(%p, %d) = %zd\n", ms, len, tocopy);
106 #endif
107 return (tocopy);
108 }
109
110 static fpos_t
memstream_seek(void * cookie,fpos_t pos,int whence)111 memstream_seek(void *cookie, fpos_t pos, int whence)
112 {
113 struct memstream *ms;
114 #ifdef DEBUG
115 fpos_t old;
116 #endif
117
118 ms = cookie;
119 #ifdef DEBUG
120 old = ms->offset;
121 #endif
122 switch (whence) {
123 case SEEK_SET:
124 /* _fseeko() checks for negative offsets. */
125 assert(pos >= 0);
126 ms->offset = pos;
127 break;
128 case SEEK_CUR:
129 /* This is only called by _ftello(). */
130 assert(pos == 0);
131 break;
132 case SEEK_END:
133 if (pos < 0) {
134 if (pos + ms->len < 0) {
135 #ifdef DEBUG
136 fprintf(stderr,
137 "MS: bad SEEK_END: pos %jd, len %zd\n",
138 (intmax_t)pos, ms->len);
139 #endif
140 errno = EINVAL;
141 return (-1);
142 }
143 } else {
144 if (FPOS_MAX - ms->len < pos) {
145 #ifdef DEBUG
146 fprintf(stderr,
147 "MS: bad SEEK_END: pos %jd, len %zd\n",
148 (intmax_t)pos, ms->len);
149 #endif
150 errno = EOVERFLOW;
151 return (-1);
152 }
153 }
154 ms->offset = ms->len + pos;
155 break;
156 }
157 memstream_update(ms);
158 #ifdef DEBUG
159 fprintf(stderr, "MS: seek(%p, %jd, %d) %jd -> %jd\n", ms, (intmax_t)pos,
160 whence, (intmax_t)old, (intmax_t)ms->offset);
161 #endif
162 return (ms->offset);
163 }
164
165 static int
memstream_close(void * cookie)166 memstream_close(void *cookie)
167 {
168
169 free(cookie);
170 return (0);
171 }
172
173 FILE *
open_memstream(char ** bufp,size_t * sizep)174 open_memstream(char **bufp, size_t *sizep)
175 {
176 struct memstream *ms;
177 int save_errno;
178 FILE *fp;
179
180 if (bufp == NULL || sizep == NULL) {
181 errno = EINVAL;
182 return (NULL);
183 }
184 *bufp = calloc(1, 1);
185 if (*bufp == NULL)
186 return (NULL);
187 ms = malloc(sizeof(*ms));
188 if (ms == NULL) {
189 save_errno = errno;
190 free(*bufp);
191 *bufp = NULL;
192 errno = save_errno;
193 return (NULL);
194 }
195 ms->bufp = bufp;
196 ms->sizep = sizep;
197 ms->len = 0;
198 ms->offset = 0;
199 memstream_update(ms);
200 fp = funopen(ms, NULL, memstream_write, memstream_seek,
201 memstream_close);
202 if (fp == NULL) {
203 save_errno = errno;
204 free(ms);
205 free(*bufp);
206 *bufp = NULL;
207 errno = save_errno;
208 return (NULL);
209 }
210 fwide(fp, -1);
211 return (fp);
212 }
213