1/*
2 * Copyright (c) 2016, EMC / Isilon Storage Division
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS
15 * IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
16 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
17 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
18 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
19 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
20 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
21 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
22 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
23 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
24 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD$");
29
30#include <sys/fcntl.h>
31
32#include <errno.h>
33#include <stdio.h>
34#include <stdlib.h>
35
36#include "local.h"
37
38struct fopencookie_thunk {
39	void			*foc_cookie;
40	cookie_io_functions_t	foc_io;
41};
42
43static int _fopencookie_read(void *, char *, int);
44static int _fopencookie_write(void *, const char *, int);
45static fpos_t _fopencookie_seek(void *, fpos_t, int);
46static int _fopencookie_close(void *);
47
48FILE *
49fopencookie(void *cookie, const char *mode, cookie_io_functions_t io_funcs)
50{
51	int (*readfn)(void *, char *, int);
52	int (*writefn)(void *, const char *, int);
53	struct fopencookie_thunk *thunk;
54	FILE *fp;
55	int flags, oflags;
56
57	if ((flags = __sflags(mode, &oflags)) == 0)
58		return (NULL);
59
60	thunk = malloc(sizeof(*thunk));
61	if (thunk == NULL)
62		return (NULL);
63
64	thunk->foc_cookie = cookie;
65	thunk->foc_io = io_funcs;
66
67	readfn = _fopencookie_read;
68	writefn = _fopencookie_write;
69	if (flags == __SWR)
70		readfn = NULL;
71	else if (flags == __SRD)
72		writefn = NULL;
73
74	fp = funopen(thunk, readfn, writefn, _fopencookie_seek,
75	    _fopencookie_close);
76	if (fp == NULL) {
77		free(thunk);
78		return (NULL);
79	}
80
81	if ((oflags & O_APPEND) != 0)
82		fp->_flags |= __SAPP;
83
84	return (fp);
85}
86
87static int
88_fopencookie_read(void *cookie, char *buf, int size)
89{
90	struct fopencookie_thunk *thunk;
91
92	thunk = cookie;
93
94	/* Reads from a stream with NULL read return EOF. */
95	if (thunk->foc_io.read == NULL)
96		return (0);
97
98	return ((int)thunk->foc_io.read(thunk->foc_cookie, buf, (size_t)size));
99}
100
101static int
102_fopencookie_write(void *cookie, const char *buf, int size)
103{
104	struct fopencookie_thunk *thunk;
105
106	thunk = cookie;
107
108	/* Writes to a stream with NULL write discard data. */
109	if (thunk->foc_io.write == NULL)
110		return (size);
111
112	return ((int)thunk->foc_io.write(thunk->foc_cookie, buf,
113		(size_t)size));
114}
115
116static fpos_t
117_fopencookie_seek(void *cookie, fpos_t offset, int whence)
118{
119	struct fopencookie_thunk *thunk;
120	off64_t off64;
121	int res;
122
123	switch (whence) {
124	case SEEK_SET:
125	case SEEK_CUR:
126	case SEEK_END:
127		break;
128	default:
129		/* fopencookie(3) only allows these three seek modes. */
130		errno = EINVAL;
131		return (-1);
132	}
133
134	thunk = cookie;
135
136	/*
137	 * If seek is NULL, it is not possible to perform seek operations on
138	 * the stream.
139	 */
140	if (thunk->foc_io.seek == NULL) {
141		errno = ENOTSUP;
142		return (-1);
143	}
144
145	off64 = (off64_t)offset;
146	res = thunk->foc_io.seek(thunk->foc_cookie, &off64, whence);
147	if (res < 0)
148		return (res);
149
150	return ((fpos_t)off64);
151}
152
153static int
154_fopencookie_close(void *cookie)
155{
156	struct fopencookie_thunk *thunk;
157	int ret, serrno;
158
159	ret = 0;
160	thunk = cookie;
161	if (thunk->foc_io.close != NULL)
162		ret = thunk->foc_io.close(thunk->foc_cookie);
163
164	serrno = errno;
165	free(thunk);
166	errno = serrno;
167	return (ret);
168}
169