open_wmemstream.c revision 283927 
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: stable/10/lib/libc/stdio/open_wmemstream.c 283927 2015-06-02 19:20:39Z jhb $");
30
31#include "namespace.h"
32#include <assert.h>
33#include <errno.h>
34#include <limits.h>
35#include <stdio.h>
36#include <stdlib.h>
37#include <string.h>
38#include <wchar.h>
39#include "un-namespace.h"
40
41/* XXX: There is no FPOS_MAX.  This assumes fpos_t is an off_t. */
42#define	FPOS_MAX	OFF_MAX
43
44struct wmemstream {
45	wchar_t **bufp;
46	size_t *sizep;
47	ssize_t len;
48	fpos_t offset;
49	mbstate_t mbstate;
50};
51
52static int
53wmemstream_grow(struct wmemstream *ms, fpos_t newoff)
54{
55	wchar_t *buf;
56	ssize_t newsize;
57
58	if (newoff < 0 || newoff >= SSIZE_MAX / sizeof(wchar_t))
59		newsize = SSIZE_MAX / sizeof(wchar_t) - 1;
60	else
61		newsize = newoff;
62	if (newsize > ms->len) {
63		buf = realloc(*ms->bufp, (newsize + 1) * sizeof(wchar_t));
64		if (buf != NULL) {
65#ifdef DEBUG
66			fprintf(stderr, "WMS: %p growing from %zd to %zd\n",
67			    ms, ms->len, newsize);
68#endif
69			wmemset(buf + ms->len + 1, 0, newsize - ms->len);
70			*ms->bufp = buf;
71			ms->len = newsize;
72			return (1);
73		}
74		return (0);
75	}
76	return (1);
77}
78
79static void
80wmemstream_update(struct wmemstream *ms)
81{
82
83	assert(ms->len >= 0 && ms->offset >= 0);
84	*ms->sizep = ms->len < ms->offset ? ms->len : ms->offset;
85}
86
87/*
88 * Based on a starting multibyte state and an input buffer, determine
89 * how many wchar_t's would be output.  This doesn't use mbsnrtowcs()
90 * so that it can handle embedded null characters.
91 */
92static size_t
93wbuflen(const mbstate_t *state, const char *buf, int len)
94{
95	mbstate_t lenstate;
96	size_t charlen, count;
97
98	count = 0;
99	lenstate = *state;
100	while (len > 0) {
101		charlen = mbrlen(buf, len, &lenstate);
102		if (charlen == (size_t)-1)
103			return (-1);
104		if (charlen == (size_t)-2)
105			break;
106		if (charlen == 0)
107			/* XXX: Not sure how else to handle this. */
108			charlen = 1;
109		len -= charlen;
110		buf += charlen;
111		count++;
112	}
113	return (count);
114}
115
116static int
117wmemstream_write(void *cookie, const char *buf, int len)
118{
119	struct wmemstream *ms;
120	ssize_t consumed, wlen;
121	size_t charlen;
122
123	ms = cookie;
124	wlen = wbuflen(&ms->mbstate, buf, len);
125	if (wlen < 0) {
126		errno = EILSEQ;
127		return (-1);
128	}
129	if (!wmemstream_grow(ms, ms->offset + wlen))
130		return (-1);
131
132	/*
133	 * This copies characters one at a time rather than using
134	 * mbsnrtowcs() so it can properly handle embedded null
135	 * characters.
136	 */
137	consumed = 0;
138	while (len > 0 && ms->offset < ms->len) {
139		charlen = mbrtowc(*ms->bufp + ms->offset, buf, len,
140		    &ms->mbstate);
141		if (charlen == (size_t)-1) {
142			if (consumed == 0) {
143				errno = EILSEQ;
144				return (-1);
145			}
146			/* Treat it as a successful short write. */
147			break;
148		}
149		if (charlen == 0)
150			/* XXX: Not sure how else to handle this. */
151			charlen = 1;
152		if (charlen == (size_t)-2) {
153			consumed += len;
154			len = 0;
155		} else {
156			consumed += charlen;
157			buf += charlen;
158			len -= charlen;
159			ms->offset++;
160		}
161	}
162	wmemstream_update(ms);
163#ifdef DEBUG
164	fprintf(stderr, "WMS: write(%p, %d) = %zd\n", ms, len, consumed);
165#endif
166	return (consumed);
167}
168
169static fpos_t
170wmemstream_seek(void *cookie, fpos_t pos, int whence)
171{
172	struct wmemstream *ms;
173	fpos_t old;
174
175	ms = cookie;
176	old = ms->offset;
177	switch (whence) {
178	case SEEK_SET:
179		/* _fseeko() checks for negative offsets. */
180		assert(pos >= 0);
181		ms->offset = pos;
182		break;
183	case SEEK_CUR:
184		/* This is only called by _ftello(). */
185		assert(pos == 0);
186		break;
187	case SEEK_END:
188		if (pos < 0) {
189			if (pos + ms->len < 0) {
190#ifdef DEBUG
191				fprintf(stderr,
192				    "WMS: bad SEEK_END: pos %jd, len %zd\n",
193				    (intmax_t)pos, ms->len);
194#endif
195				errno = EINVAL;
196				return (-1);
197			}
198		} else {
199			if (FPOS_MAX - ms->len < pos) {
200#ifdef DEBUG
201				fprintf(stderr,
202				    "WMS: bad SEEK_END: pos %jd, len %zd\n",
203				    (intmax_t)pos, ms->len);
204#endif
205				errno = EOVERFLOW;
206				return (-1);
207			}
208		}
209		ms->offset = ms->len + pos;
210		break;
211	}
212	/* Reset the multibyte state if a seek changes the position. */
213	if (ms->offset != old)
214		memset(&ms->mbstate, 0, sizeof(ms->mbstate));
215	wmemstream_update(ms);
216#ifdef DEBUG
217	fprintf(stderr, "WMS: seek(%p, %jd, %d) %jd -> %jd\n", ms,
218	    (intmax_t)pos, whence, (intmax_t)old, (intmax_t)ms->offset);
219#endif
220	return (ms->offset);
221}
222
223static int
224wmemstream_close(void *cookie)
225{
226
227	free(cookie);
228	return (0);
229}
230
231FILE *
232open_wmemstream(wchar_t **bufp, size_t *sizep)
233{
234	struct wmemstream *ms;
235	int save_errno;
236	FILE *fp;
237
238	if (bufp == NULL || sizep == NULL) {
239		errno = EINVAL;
240		return (NULL);
241	}
242	*bufp = calloc(1, sizeof(wchar_t));
243	if (*bufp == NULL)
244		return (NULL);
245	ms = malloc(sizeof(*ms));
246	if (ms == NULL) {
247		save_errno = errno;
248		free(*bufp);
249		*bufp = NULL;
250		errno = save_errno;
251		return (NULL);
252	}
253	ms->bufp = bufp;
254	ms->sizep = sizep;
255	ms->len = 0;
256	ms->offset = 0;
257	memset(&ms->mbstate, 0, sizeof(mbstate_t));
258	wmemstream_update(ms);
259	fp = funopen(ms, NULL, wmemstream_write, wmemstream_seek,
260	    wmemstream_close);
261	if (fp == NULL) {
262		save_errno = errno;
263		free(ms);
264		free(*bufp);
265		*bufp = NULL;
266		errno = save_errno;
267		return (NULL);
268	}
269	fwide(fp, 1);
270	return (fp);
271}
272