1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2013 Hudson River Trading LLC
5 * Written by: John H. Baldwin <jhb@FreeBSD.org>
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30 #include "namespace.h"
31 #include <assert.h>
32 #include <errno.h>
33 #include <limits.h>
34 #ifdef DEBUG
35 #include <stdint.h>
36 #endif
37 #include <stdio.h>
38 #include <stdlib.h>
39 #include <string.h>
40 #include <wchar.h>
41 #include "un-namespace.h"
42
43 /* XXX: There is no FPOS_MAX. This assumes fpos_t is an off_t. */
44 #define FPOS_MAX OFF_MAX
45
46 struct memstream {
47 char **bufp;
48 size_t *sizep;
49 ssize_t len;
50 fpos_t offset;
51 };
52
53 static int
memstream_grow(struct memstream * ms,fpos_t newoff)54 memstream_grow(struct memstream *ms, fpos_t newoff)
55 {
56 char *buf;
57 ssize_t newsize;
58
59 if (newoff < 0 || newoff >= SSIZE_MAX)
60 newsize = SSIZE_MAX - 1;
61 else
62 newsize = newoff;
63 if (newsize > ms->len) {
64 buf = realloc(*ms->bufp, newsize + 1);
65 if (buf != NULL) {
66 #ifdef DEBUG
67 fprintf(stderr, "MS: %p growing from %zd to %zd\n",
68 ms, ms->len, newsize);
69 #endif
70 memset(buf + ms->len + 1, 0, newsize - ms->len);
71 *ms->bufp = buf;
72 ms->len = newsize;
73 return (1);
74 }
75 return (0);
76 }
77 return (1);
78 }
79
80 static void
memstream_update(struct memstream * ms)81 memstream_update(struct memstream *ms)
82 {
83
84 assert(ms->len >= 0 && ms->offset >= 0);
85 *ms->sizep = ms->len < ms->offset ? ms->len : ms->offset;
86 }
87
88 static int
memstream_write(void * cookie,const char * buf,int len)89 memstream_write(void *cookie, const char *buf, int len)
90 {
91 struct memstream *ms;
92 ssize_t tocopy;
93
94 ms = cookie;
95 if (!memstream_grow(ms, ms->offset + len))
96 return (-1);
97 tocopy = ms->len - ms->offset;
98 if (len < tocopy)
99 tocopy = len;
100 memcpy(*ms->bufp + ms->offset, buf, tocopy);
101 ms->offset += tocopy;
102 memstream_update(ms);
103 #ifdef DEBUG
104 fprintf(stderr, "MS: write(%p, %d) = %zd\n", ms, len, tocopy);
105 #endif
106 return (tocopy);
107 }
108
109 static fpos_t
memstream_seek(void * cookie,fpos_t pos,int whence)110 memstream_seek(void *cookie, fpos_t pos, int whence)
111 {
112 struct memstream *ms;
113 #ifdef DEBUG
114 fpos_t old;
115 #endif
116
117 ms = cookie;
118 #ifdef DEBUG
119 old = ms->offset;
120 #endif
121 switch (whence) {
122 case SEEK_SET:
123 /* _fseeko() checks for negative offsets. */
124 assert(pos >= 0);
125 ms->offset = pos;
126 break;
127 case SEEK_CUR:
128 /* This is only called by _ftello(). */
129 assert(pos == 0);
130 break;
131 case SEEK_END:
132 if (pos < 0) {
133 if (pos + ms->len < 0) {
134 #ifdef DEBUG
135 fprintf(stderr,
136 "MS: bad SEEK_END: pos %jd, len %zd\n",
137 (intmax_t)pos, ms->len);
138 #endif
139 errno = EINVAL;
140 return (-1);
141 }
142 } else {
143 if (FPOS_MAX - ms->len < pos) {
144 #ifdef DEBUG
145 fprintf(stderr,
146 "MS: bad SEEK_END: pos %jd, len %zd\n",
147 (intmax_t)pos, ms->len);
148 #endif
149 errno = EOVERFLOW;
150 return (-1);
151 }
152 }
153 ms->offset = ms->len + pos;
154 break;
155 }
156 memstream_update(ms);
157 #ifdef DEBUG
158 fprintf(stderr, "MS: seek(%p, %jd, %d) %jd -> %jd\n", ms, (intmax_t)pos,
159 whence, (intmax_t)old, (intmax_t)ms->offset);
160 #endif
161 return (ms->offset);
162 }
163
164 static int
memstream_close(void * cookie)165 memstream_close(void *cookie)
166 {
167
168 free(cookie);
169 return (0);
170 }
171
172 FILE *
open_memstream(char ** bufp,size_t * sizep)173 open_memstream(char **bufp, size_t *sizep)
174 {
175 struct memstream *ms;
176 int save_errno;
177 FILE *fp;
178
179 if (bufp == NULL || sizep == NULL) {
180 errno = EINVAL;
181 return (NULL);
182 }
183 *bufp = calloc(1, 1);
184 if (*bufp == NULL)
185 return (NULL);
186 ms = malloc(sizeof(*ms));
187 if (ms == NULL) {
188 save_errno = errno;
189 free(*bufp);
190 *bufp = NULL;
191 errno = save_errno;
192 return (NULL);
193 }
194 ms->bufp = bufp;
195 ms->sizep = sizep;
196 ms->len = 0;
197 ms->offset = 0;
198 memstream_update(ms);
199 fp = funopen(ms, NULL, memstream_write, memstream_seek,
200 memstream_close);
201 if (fp == NULL) {
202 save_errno = errno;
203 free(ms);
204 free(*bufp);
205 *bufp = NULL;
206 errno = save_errno;
207 return (NULL);
208 }
209 fwide(fp, -1);
210 return (fp);
211 }
212