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readdir.c revision 1.13 
      1 /*	$NetBSD: readdir.c,v 1.13 1999/09/16 11:45:03 lukem Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1983, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 #if defined(LIBC_SCCS) && !defined(lint)
     38 #if 0
     39 static char sccsid[] = "@(#)readdir.c	8.3 (Berkeley) 9/29/94";
     40 #else
     41 __RCSID("$NetBSD: readdir.c,v 1.13 1999/09/16 11:45:03 lukem Exp $");
     42 #endif
     43 #endif /* LIBC_SCCS and not lint */
     44 
     45 #include "namespace.h"
     46 #include <sys/param.h>
     47 
     48 #include <dirent.h>
     49 #include <errno.h>
     50 #include <unistd.h>
     51 
     52 #ifdef __weak_alias
     53 __weak_alias(readdir,_readdir);
     54 #endif
     55 
     56 /*
     57  * get next entry in a directory.
     58  */
     59 struct dirent *
     60 readdir(dirp)
     61 	DIR *dirp;
     62 {
     63 	struct dirent *dp;
     64 
     65 #ifdef _DIAGNOSTIC
     66 	if (dirp == NULL) {
     67 		errno = EBADF;
     68 		return (NULL);
     69 	}
     70 #endif
     71 
     72 	for (;;) {
     73 		if (dirp->dd_loc >= dirp->dd_size) {
     74 			if (dirp->dd_flags & __DTF_READALL)
     75 				return (NULL);
     76 			dirp->dd_loc = 0;
     77 		}
     78 		if (dirp->dd_loc == 0 && !(dirp->dd_flags & __DTF_READALL)) {
     79 			dirp->dd_seek = lseek(dirp->dd_fd, (off_t)0, SEEK_CUR);
     80 			dirp->dd_size = getdents(dirp->dd_fd,
     81 			    dirp->dd_buf, (size_t)dirp->dd_len);
     82 			if (dirp->dd_size <= 0)
     83 				return (NULL);
     84 		}
     85 		dp = (struct dirent *)
     86 		    (void *)(dirp->dd_buf + (size_t)dirp->dd_loc);
     87 		if ((long)dp & 03)	/* bogus pointer check */
     88 			return (NULL);
     89 		/* d_reclen is unsigned; no need to compare it <= 0 */
     90 		if (dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc)
     91 			return (NULL);
     92 		dirp->dd_loc += dp->d_reclen;
     93 		if (dp->d_ino == 0)
     94 			continue;
     95 		if (dp->d_type == DT_WHT && (dirp->dd_flags & DTF_HIDEW))
     96 			continue;
     97 		return (dp);
     98 	}
     99 }
    100