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funopen.c revision 1.10.44.1 
      1 /*	$NetBSD: funopen.c,v 1.10.44.1 2012/04/17 00:05:24 yamt 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 1.10.44.1 2012/04/17 00:05:24 yamt 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 *
     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
     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
    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
    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
    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 *
    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