1 /* $NetBSD: funopen.c,v 1.14 2012/03/28 15:21:11 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
38 static char sccsid[] = "@(#)funopen.c 8.1 (Berkeley) 6/4/93";
39 #else
40 __RCSID("$NetBSD: funopen.c,v 1.14 2012/03/28 15:21:11 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
51 FILE *
funopen2(const void * cookie,ssize_t (* readfn)(void *,void *,size_t),ssize_t (* writefn)(void *,const void *,size_t),off_t (* seekfn)(void *,off_t,int),int (* flushfn)(void *),int (* closefn)(void *))52 funopen2(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
87 typedef 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
95 static ssize_t
creadfn(void * dookie,void * buf,size_t len)96 creadfn(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
104 static ssize_t
cwritefn(void * dookie,const void * buf,size_t len)105 cwritefn(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
127 static off_t
cseekfn(void * dookie,off_t off,int whence)128 cseekfn(void *dookie, off_t off, int whence)
129 {
130 dookie_t *d = dookie;
131 return (*d->seekfn)(d->cookie, off, whence);
132 }
133
134 static int
cclosefn(void * dookie)135 cclosefn(void *dookie)
136 {
137 dookie_t *d = dookie;
138 void *c = d->cookie;
139 int (*cf)(void *) = d->closefn;
140 free(dookie);
141 return (*cf)(c);
142 }
143
144 FILE *
funopen(const void * cookie,int (* readfn)(void *,char *,int),int (* writefn)(void *,const char *,int),off_t (* seekfn)(void *,off_t,int),int (* closefn)(void *))145 funopen(const void *cookie,
146 int (*readfn)(void *, char *, int),
147 int (*writefn)(void *, const char *, int),
148 off_t (*seekfn)(void *, off_t, int),
149 int (*closefn)(void *))
150 {
151 dookie_t *d;
152 FILE *fp;
153
154 if ((d = malloc(sizeof(*d))) == NULL)
155 return NULL;
156
157 d->cookie = __UNCONST(cookie);
158 d->readfn = readfn;
159 d->writefn = writefn;
160 d->seekfn = seekfn;
161 d->closefn = closefn;
162 fp = funopen2(d,
163 d->readfn ? creadfn : NULL,
164 d->writefn ? cwritefn : NULL,
165 d->seekfn ? cseekfn : NULL,
166 NULL,
167 d->closefn ? cclosefn : NULL);
168 if (fp != NULL)
169 return fp;
170 free(d);
171 return NULL;
172 }
173