xref: /openbsd/lib/libc/stdio/funopen.c (revision 7b36286a)
1 /*	$OpenBSD: funopen.c,v 1.8 2005/08/08 08:05:36 espie Exp $ */
2 /*-
3  * Copyright (c) 1990, 1993
4  *	The Regents of the University of California.  All rights reserved.
5  *
6  * This code is derived from software contributed to Berkeley by
7  * Chris Torek.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #include <stdio.h>
35 #include <errno.h>
36 #include "local.h"
37 
38 FILE *
39 funopen(const void *cookie, int (*readfn)(void *, char *, int),
40 	int (*writefn)(void *, const char *, int),
41 	fpos_t (*seekfn)(void *, fpos_t, int), int (*closefn)(void *))
42 {
43 	FILE *fp;
44 	int flags;
45 
46 	if (readfn == NULL) {
47 		if (writefn == NULL) {		/* illegal */
48 			errno = EINVAL;
49 			return (NULL);
50 		} else
51 			flags = __SWR;		/* write only */
52 	} else {
53 		if (writefn == NULL)
54 			flags = __SRD;		/* read only */
55 		else
56 			flags = __SRW;		/* read-write */
57 	}
58 	if ((fp = __sfp()) == NULL)
59 		return (NULL);
60 	fp->_flags = flags;
61 	fp->_file = -1;
62 	fp->_cookie = (void *)cookie;		/* SAFE: cookie not modified */
63 	fp->_read = readfn;
64 	fp->_write = writefn;
65 	fp->_seek = seekfn;
66 	fp->_close = closefn;
67 	return (fp);
68 }
69