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compat_getdents.c revision 1.6 
      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
     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