open_wmemstream.c revision 331722 
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/11/lib/libc/stdio/open_wmemstream.c 331722 2018-03-29 02:50:57Z eadler $");
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
47struct wmemstream {
48	wchar_t **bufp;
49	size_t *sizep;
50	ssize_t len;
51	fpos_t offset;
52	mbstate_t mbstate;
53};
54
55static int
56wmemstream_grow(struct wmemstream *ms, fpos_t newoff)
57{
58	wchar_t *buf;
59	ssize_t newsize;
60
61	if (newoff < 0 || newoff >= SSIZE_MAX / sizeof(wchar_t))
62		newsize = SSIZE_MAX / sizeof(wchar_t) - 1;
63	else
64		newsize = newoff;
65	if (newsize > ms->len) {
66		buf = reallocarray(*ms->bufp, newsize + 1, sizeof(wchar_t));
67		if (buf != NULL) {
68#ifdef DEBUG
69			fprintf(stderr, "WMS: %p growing from %zd to %zd\n",
70			    ms, ms->len, newsize);
71#endif
72			wmemset(buf + ms->len + 1, 0, newsize - ms->len);
73			*ms->bufp = buf;
74			ms->len = newsize;
75			return (1);
76		}
77		return (0);
78	}
79	return (1);
80}
81
82static void
83wmemstream_update(struct wmemstream *ms)
84{
85
86	assert(ms->len >= 0 && ms->offset >= 0);
87	*ms->sizep = ms->len < ms->offset ? ms->len : ms->offset;
88}
89
90/*
91 * Based on a starting multibyte state and an input buffer, determine
92 * how many wchar_t's would be output.  This doesn't use mbsnrtowcs()
93 * so that it can handle embedded null characters.
94 */
95static size_t
96wbuflen(const mbstate_t *state, const char *buf, int len)
97{
98	mbstate_t lenstate;
99	size_t charlen, count;
100
101	count = 0;
102	lenstate = *state;
103	while (len > 0) {
104		charlen = mbrlen(buf, len, &lenstate);
105		if (charlen == (size_t)-1)
106			return (-1);
107		if (charlen == (size_t)-2)
108			break;
109		if (charlen == 0)
110			/* XXX: Not sure how else to handle this. */
111			charlen = 1;
112		len -= charlen;
113		buf += charlen;
114		count++;
115	}
116	return (count);
117}
118
119static int
120wmemstream_write(void *cookie, const char *buf, int len)
121{
122	struct wmemstream *ms;
123	ssize_t consumed, wlen;
124	size_t charlen;
125
126	ms = cookie;
127	wlen = wbuflen(&ms->mbstate, buf, len);
128	if (wlen < 0) {
129		errno = EILSEQ;
130		return (-1);
131	}
132	if (!wmemstream_grow(ms, ms->offset + wlen))
133		return (-1);
134
135	/*
136	 * This copies characters one at a time rather than using
137	 * mbsnrtowcs() so it can properly handle embedded null
138	 * characters.
139	 */
140	consumed = 0;
141	while (len > 0 && ms->offset < ms->len) {
142		charlen = mbrtowc(*ms->bufp + ms->offset, buf, len,
143		    &ms->mbstate);
144		if (charlen == (size_t)-1) {
145			if (consumed == 0) {
146				errno = EILSEQ;
147				return (-1);
148			}
149			/* Treat it as a successful short write. */
150			break;
151		}
152		if (charlen == 0)
153			/* XXX: Not sure how else to handle this. */
154			charlen = 1;
155		if (charlen == (size_t)-2) {
156			consumed += len;
157			len = 0;
158		} else {
159			consumed += charlen;
160			buf += charlen;
161			len -= charlen;
162			ms->offset++;
163		}
164	}
165	wmemstream_update(ms);
166#ifdef DEBUG
167	fprintf(stderr, "WMS: write(%p, %d) = %zd\n", ms, len, consumed);
168#endif
169	return (consumed);
170}
171
172static fpos_t
173wmemstream_seek(void *cookie, fpos_t pos, int whence)
174{
175	struct wmemstream *ms;
176	fpos_t old;
177
178	ms = cookie;
179	old = ms->offset;
180	switch (whence) {
181	case SEEK_SET:
182		/* _fseeko() checks for negative offsets. */
183		assert(pos >= 0);
184		ms->offset = pos;
185		break;
186	case SEEK_CUR:
187		/* This is only called by _ftello(). */
188		assert(pos == 0);
189		break;
190	case SEEK_END:
191		if (pos < 0) {
192			if (pos + ms->len < 0) {
193#ifdef DEBUG
194				fprintf(stderr,
195				    "WMS: bad SEEK_END: pos %jd, len %zd\n",
196				    (intmax_t)pos, ms->len);
197#endif
198				errno = EINVAL;
199				return (-1);
200			}
201		} else {
202			if (FPOS_MAX - ms->len < pos) {
203#ifdef DEBUG
204				fprintf(stderr,
205				    "WMS: bad SEEK_END: pos %jd, len %zd\n",
206				    (intmax_t)pos, ms->len);
207#endif
208				errno = EOVERFLOW;
209				return (-1);
210			}
211		}
212		ms->offset = ms->len + pos;
213		break;
214	}
215	/* Reset the multibyte state if a seek changes the position. */
216	if (ms->offset != old)
217		memset(&ms->mbstate, 0, sizeof(ms->mbstate));
218	wmemstream_update(ms);
219#ifdef DEBUG
220	fprintf(stderr, "WMS: seek(%p, %jd, %d) %jd -> %jd\n", ms,
221	    (intmax_t)pos, whence, (intmax_t)old, (intmax_t)ms->offset);
222#endif
223	return (ms->offset);
224}
225
226static int
227wmemstream_close(void *cookie)
228{
229
230	free(cookie);
231	return (0);
232}
233
234FILE *
235open_wmemstream(wchar_t **bufp, size_t *sizep)
236{
237	struct wmemstream *ms;
238	int save_errno;
239	FILE *fp;
240
241	if (bufp == NULL || sizep == NULL) {
242		errno = EINVAL;
243		return (NULL);
244	}
245	*bufp = calloc(1, sizeof(wchar_t));
246	if (*bufp == NULL)
247		return (NULL);
248	ms = malloc(sizeof(*ms));
249	if (ms == NULL) {
250		save_errno = errno;
251		free(*bufp);
252		*bufp = NULL;
253		errno = save_errno;
254		return (NULL);
255	}
256	ms->bufp = bufp;
257	ms->sizep = sizep;
258	ms->len = 0;
259	ms->offset = 0;
260	memset(&ms->mbstate, 0, sizeof(mbstate_t));
261	wmemstream_update(ms);
262	fp = funopen(ms, NULL, wmemstream_write, wmemstream_seek,
263	    wmemstream_close);
264	if (fp == NULL) {
265		save_errno = errno;
266		free(ms);
267		free(*bufp);
268		*bufp = NULL;
269		errno = save_errno;
270		return (NULL);
271	}
272	fwide(fp, 1);
273	return (fp);
274}
275