lib/libc/compat/sys/compat_getdents.c

   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 }