1 /*	$NetBSD: compat_getdents.c,v 1.6 2012/03/13 22:24:48 joerg Exp $	*/
2 
3 /*-
4  * Copyright (c) 2005 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Christos Zoulas.
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  *
19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29  * POSSIBILITY OF SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 #if defined(LIBC_SCCS) && !defined(lint)
34 __RCSID("$NetBSD: compat_getdents.c,v 1.6 2012/03/13 22:24:48 joerg Exp $");
35 #endif /* LIBC_SCCS and not lint */
36 
37 #define __LIBC12_SOURCE__
38 
39 #include "namespace.h"
40 #include <sys/types.h>
41 #include <assert.h>
42 #include <dirent.h>
43 #include <stddef.h>
44 #include <compat/include/dirent.h>
45 #include <string.h>
46 
47 /*
48  * libc12 compatible getdents routine.
49  */
50 int
getdents(int fd,char * buf,size_t nbytes)51 getdents(int fd, char *buf, size_t nbytes)
52 {
53 	struct dirent *ndp, *nndp, *endp;
54 	struct dirent12 *odp;
55 	ino_t ino;
56 	int rv;
57 	size_t len;
58 
59 	if ((rv = __getdents30(fd, buf, nbytes)) == -1)
60 		return rv;
61 
62 	odp = (struct dirent12 *)(void *)buf;
63 	ndp = (struct dirent *)(void *)buf;
64 	endp = (struct dirent *)(void *)&buf[rv];
65 
66 	/*
67 	 * In-place conversion. This works because odp
68 	 * is smaller than ndp, but it has to be done
69 	 * in the right sequence.
70 	 */
71 	for (; ndp < endp; ndp = nndp) {
72 		nndp = _DIRENT_NEXT(ndp);
73 		/* XXX: avoid unaligned 64-bit access on sparc64 */
74 		/* XXX: does this work? */
75 		memcpy(&ino, &ndp->d_ino, sizeof(ino_t));
76 		odp->d_ino = (uint32_t)ino;
77 		if (ndp->d_namlen >= sizeof(odp->d_name))
78 			odp->d_namlen = sizeof(odp->d_name) - 1;
79 		else
80 			odp->d_namlen = (u_int8_t)ndp->d_namlen;
81 		odp->d_type = ndp->d_type;
82 		(void)memcpy(odp->d_name, ndp->d_name, (size_t)odp->d_namlen);
83 		odp->d_name[odp->d_namlen] = '\0';
84 		len = _DIRENT_SIZE(odp);
85 		_DIAGASSERT(__type_fit(uint16_t, len));
86 		odp->d_reclen = (uint16_t)len;
87 		odp = _DIRENT_NEXT(odp);
88 	}
89 	ptrdiff_t td = (((char *)(void *)odp) - buf);
90 	_DIAGASSERT(__type_fit(int, td));
91 	return (int)td;
92 }
93