funopen.c revision 1.13
1/* $NetBSD: funopen.c,v 1.13 2012/03/27 15:05:42 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 1.13 2012/03/27 15:05:42 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 return (*cf)(c); 142} 143 144FILE * 145funopen(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, creadfn, cwritefn, cseekfn, NULL, cclosefn); 163 if (fp != NULL) 164 return fp; 165 free(d); 166 return NULL; 167 } 168