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readdir.c revision 1.3 
      1 /*
      2  * Copyright (c) 1983, 1993
      3  *	The Regents of the University of California.  All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  * 3. All advertising materials mentioning features or use of this software
     14  *    must display the following acknowledgement:
     15  *	This product includes software developed by the University of
     16  *	California, Berkeley and its contributors.
     17  * 4. Neither the name of the University nor the names of its contributors
     18  *    may be used to endorse or promote products derived from this software
     19  *    without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  */
     33 
     34 #if defined(LIBC_SCCS) && !defined(lint)
     35 /*static char sccsid[] = "from: @(#)readdir.c	8.1 (Berkeley) 6/4/93";*/
     36 static char rcsid[] = "$Id: readdir.c,v 1.3 1994/10/19 03:13:42 cgd Exp $";
     37 #endif /* LIBC_SCCS and not lint */
     38 
     39 #include <sys/param.h>
     40 #include <dirent.h>
     41 
     42 /*
     43  * get next entry in a directory.
     44  */
     45 struct dirent *
     46 readdir(dirp)
     47 	register DIR *dirp;
     48 {
     49 	register struct dirent *dp;
     50 
     51 	for (;;) {
     52 		if (dirp->dd_loc == 0) {
     53 			dirp->dd_size = getdirentries(dirp->dd_fd,
     54 			    dirp->dd_buf, dirp->dd_len, &dirp->dd_seek);
     55 			if (dirp->dd_size <= 0)
     56 				return NULL;
     57 		}
     58 		if (dirp->dd_loc >= dirp->dd_size) {
     59 			dirp->dd_loc = 0;
     60 			continue;
     61 		}
     62 		dp = (struct dirent *)(dirp->dd_buf + dirp->dd_loc);
     63 		if ((long)dp & 03)	/* bogus pointer check */
     64 			return NULL;
     65 		if (dp->d_reclen <= 0 ||
     66 		    dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc)
     67 			return NULL;
     68 		dirp->dd_loc += dp->d_reclen;
     69 		if (dp->d_ino == 0)
     70 			continue;
     71 		return (dp);
     72 	}
     73 }
     74