1/*	$NetBSD: funopen.c,v 1.15 2016/10/23 21:01:52 christos Exp $	*/
2
3/*-
4 * Copyright (c) 1990, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Chris Torek.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 *    may be used to endorse or promote products derived from this software
20 *    without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35#include <sys/cdefs.h>
36#if defined(LIBC_SCCS) && !defined(lint)
37#if 0
38static char sccsid[] = "@(#)funopen.c	8.1 (Berkeley) 6/4/93";
39#else
40__RCSID("$NetBSD: funopen.c,v 1.15 2016/10/23 21:01:52 christos Exp $");
41#endif
42#endif /* LIBC_SCCS and not lint */
43
44#include <stdio.h>
45#include <errno.h>
46#include <stdlib.h>
47#include <stddef.h>
48#include "reentrant.h"
49#include "local.h"
50
51FILE *
52funopen2(const void *cookie,
53    ssize_t (*readfn)(void *, void *, size_t),
54    ssize_t (*writefn)(void *, const void *, size_t),
55    off_t (*seekfn)(void *, off_t, int),
56    int (*flushfn)(void *),
57    int (*closefn)(void *))
58{
59	FILE *fp;
60	int flags;
61
62	if (readfn == NULL) {
63		if (writefn == NULL) {		/* illegal */
64			errno = EINVAL;
65			return NULL;
66		} else
67			flags = __SWR;		/* write only */
68	} else {
69		if (writefn == NULL)
70			flags = __SRD;		/* read only */
71		else
72			flags = __SRW;		/* read-write */
73	}
74	if ((fp = __sfp()) == NULL)
75		return NULL;
76	fp->_flags = flags;
77	fp->_file = -1;
78	fp->_cookie = __UNCONST(cookie);
79	fp->_read = readfn;
80	fp->_write = writefn;
81	fp->_seek = seekfn;
82	fp->_flush = flushfn;
83	fp->_close = closefn;
84	return fp;
85}
86
87typedef struct {
88	void *cookie;
89	int (*readfn)(void *, char *, int);
90	int (*writefn)(void *, const char *, int);
91	off_t (*seekfn)(void *, off_t, int);
92	int (*closefn)(void *);
93} dookie_t;
94
95static ssize_t
96creadfn(void *dookie, void *buf, size_t len)
97{
98	dookie_t *d = dookie;
99	if (len > INT_MAX)
100		len = INT_MAX;
101	return (*d->readfn)(d->cookie, buf, (int)len);
102}
103
104static ssize_t
105cwritefn(void *dookie, const void *buf, size_t len)
106{
107	dookie_t *d = dookie;
108	ssize_t nr;
109	size_t l = len;
110	const char *b = buf;
111
112	while (l) {
113		size_t nw = l > INT_MAX ? INT_MAX : l;
114		nr = (*d->writefn)(d->cookie, buf, (int)nw);
115		if (nr == -1) {
116			if (len == l)
117				return -1;
118			else
119				return len - l;
120		}
121		b += nr;
122		l -= nr;
123	}
124	return len;
125}
126
127static off_t
128cseekfn(void *dookie, off_t off, int whence)
129{
130	dookie_t *d = dookie;
131	return (*d->seekfn)(d->cookie, off, whence);
132}
133
134static int
135cclosefn(void *dookie)
136{
137	dookie_t *d = dookie;
138	void *c = d->cookie;
139	int (*cf)(void *) = d->closefn;
140	free(dookie);
141	if (cf == NULL)
142		return 0;
143	return (*cf)(c);
144}
145
146FILE *
147funopen(const void *cookie,
148    int (*readfn)(void *, char *, int),
149    int (*writefn)(void *, const char *, int),
150    off_t (*seekfn)(void *, off_t, int),
151    int (*closefn)(void *))
152{
153	dookie_t *d;
154	FILE *fp;
155
156	if ((d = malloc(sizeof(*d))) == NULL)
157		return NULL;
158
159	d->cookie = __UNCONST(cookie);
160	d->readfn = readfn;
161	d->writefn = writefn;
162	d->seekfn = seekfn;
163	d->closefn = closefn;
164	fp = funopen2(d,
165	    d->readfn ? creadfn : NULL,
166	    d->writefn ? cwritefn : NULL,
167	    d->seekfn ? cseekfn : NULL,
168	    NULL, cclosefn);
169	if (fp != NULL)
170		return fp;
171	free(d);
172	return NULL;
173 }
174