lib/libc/stdio/funopen.c

   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 *
  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  }