Add the -d flag (limit display depth) for compatibility with FreeBSD,

DragonFly, NetBSD and GNU coreutils, even though it's not POSIX.
Actually, this simplifies the code rather than complicating it.

Because -a and -d need not be mutually exclusive (as observed by
millert@) and -s is identical to -d 0, -a and -s are no longer
mutually exclusive, but -as and -sa are now the same as -s.
That is explicitly allowed by POSIX.

Based on a patch from William Orr <will at worrbase dot com>,
but extensively massaged and HISTORY added by me.

feedback and ok millert@

2 files changed, 92 insertions, 32 deletions

diff --git a/usr.bin/du/du.1 b/usr.bin/du/du.1
index 0097b28e15e..2626cdc7b49 100644
--- a/usr.bin/du/du.1
+++ b/usr.bin/du/du.1
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: du.1,v 1.31 2014/02/14 18:17:50 schwarze Exp $
+.\"	$OpenBSD: du.1,v 1.32 2014/10/17 14:46:54 schwarze Exp $
 .\"	$NetBSD: du.1,v 1.6 1996/10/18 07:20:31 thorpej Exp $
 .\"
 .\" Copyright (c) 1990, 1993
@@ -30,7 +30,7 @@
 .\"
 .\"	@(#)du.1	8.2 (Berkeley) 4/1/94
 .\"
-.Dd $Mdocdate: February 14 2014 $
+.Dd $Mdocdate: October 17 2014 $
 .Dt DU 1
 .Os
 .Sh NAME
@@ -38,8 +38,8 @@
 .Nd display disk usage statistics
 .Sh SYNOPSIS
 .Nm du
-.Op Fl a | s
-.Op Fl chkrx
+.Op Fl d Ar depth
+.Op Fl achkrsx
 .Op Fl H | L | P
 .Op Ar
 .Sh DESCRIPTION
@@ -58,9 +58,21 @@ the current directory is displayed.
 The options are as follows:
 .Bl -tag -width Ds
 .It Fl a
-Display an entry for each file in the file hierarchy.
+Display entries for files in addition to entries for directories.
 .It Fl c
 Display the grand total after all the arguments have been processed.
+.It Fl d Ar depth
+Do not display entries for files and directories more than
+.Ar depth
+levels deep;
+.Fl d Cm 0
+has the same effect as
+.Fl s .
+Overrides earlier
+.Fl d
+and
+.Fl s
+options.
 .It Fl H
 Symbolic links on the command line are followed.
 Symbolic links encountered in the tree traversal are not followed.
@@ -83,7 +95,10 @@ Generate messages about directories that cannot be read, files
 that cannot be opened, and so on.
 This is the default.
 .It Fl s
-Display only the grand total for the specified files.
+Display only the total for each of the specified files and directories.
+Overrides earlier
+.Fl d
+options.
 .It Fl x
 File system mount points are not traversed.
 .El
@@ -145,7 +160,7 @@ utility is compliant with the
 specification.
 .Pp
 The flags
-.Op Fl chP ,
+.Op Fl cdhP ,
 as well as the
 .Ev BLOCKSIZE
 environment variable,
@@ -158,10 +173,55 @@ the obsolete
 .St -xcu5
 standard.
 .Sh HISTORY
-A
+The
 .Nm
-command first appeared in
-.At v3 .
+utility and its
+.Fl a
+and
+.Fl s
+options first appeared in
+.At v1 .
+.Pp
+The
+.Fl r
+option first appeared in
+.At III
+and is available since
+.Ox 2.3 .
+The
+.Fl k
+and
+.Fl x
+options first appeared in
+.Bx 4.3 Reno
+and
+.Fl H
+in
+.Bx 4.4 .
+The
+.Fl c
+and
+.Fl L
+options first appeared in the GNU fileutils;
+.Fl L
+and
+.Fl P
+are available since
+.Bx 4.4 Lite1 ,
+.Fl c
+since
+.Ox 2.1 .
+The
+.Fl d
+option first appeared in
+.Fx 2.2
+and is available since
+.Ox 5.7 ,
+.Fl h
+first appeared in
+.Fx 4.0
+and is available since
+.Ox 2.9 .
 .Sh AUTHORS
 .An -nosplit
 This version of
diff --git a/usr.bin/du/du.c b/usr.bin/du/du.c
index 550af7ec062..1764ab6d447 100644
--- a/usr.bin/du/du.c
+++ b/usr.bin/du/du.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: du.c,v 1.25 2014/05/20 01:25:23 guenther Exp $	*/
+/*	$OpenBSD: du.c,v 1.26 2014/10/17 14:46:54 schwarze Exp $	*/
 /*	$NetBSD: du.c,v 1.11 1996/10/18 07:20:35 thorpej Exp $	*/
 
 /*
@@ -40,6 +40,7 @@
 #include <err.h>
 #include <errno.h>
 #include <fts.h>
+#include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -59,16 +60,18 @@ main(int argc, char *argv[])
 	FTSENT *p;
 	long blocksize;
 	quad_t totalblocks;
-	int ftsoptions, listdirs, listfiles;
-	int Hflag, Lflag, aflag, cflag, hflag, kflag, sflag;
+	int ftsoptions, listfiles, maxdepth;
+	int Hflag, Lflag, cflag, hflag, kflag;
 	int ch, notused, rval;
 	char **save;
+	const char *errstr;
 
 	save = argv;
-	Hflag = Lflag = aflag = cflag = hflag = kflag = sflag = 0;
+	Hflag = Lflag = cflag = hflag = kflag = listfiles = 0;
 	totalblocks = 0;
 	ftsoptions = FTS_PHYSICAL;
-	while ((ch = getopt(argc, argv, "HLPachksxr")) != -1)
+	maxdepth = -1;
+	while ((ch = getopt(argc, argv, "HLPacd:hkrsx")) != -1)
 		switch (ch) {
 		case 'H':
 			Hflag = 1;
@@ -82,11 +85,18 @@ main(int argc, char *argv[])
 			Hflag = Lflag = 0;
 			break;
 		case 'a':
-			aflag = 1;
+			listfiles = 1;
 			break;
 		case 'c':
 			cflag = 1;
 			break;
+		case 'd':
+			maxdepth = strtonum(optarg, 0, INT_MAX, &errstr);
+			if (errstr) {
+				warnx("max depth %s: %s", optarg, errstr);
+				usage();
+			}
+			break;
 		case 'h':
 			hflag = 1;
 			kflag = 0;
@@ -96,7 +106,7 @@ main(int argc, char *argv[])
 			hflag = 0;
 			break;
 		case 's':
-			sflag = 1;
+			maxdepth = 0;
 			break;
 		case 'r':
 			break;
@@ -129,16 +139,8 @@ main(int argc, char *argv[])
 		ftsoptions |= FTS_LOGICAL;
 	}
 
-	if (aflag) {
-		if (sflag)
-			usage();
-		listdirs = listfiles = 1;
-	} else if (sflag)
-		listdirs = listfiles = 0;
-	else {
-		listfiles = 0;
-		listdirs = 1;
-	}
+	if (maxdepth == -1)
+		maxdepth = INT_MAX;
 
 	if (!*argv) {
 		argv = save;
@@ -171,12 +173,10 @@ main(int argc, char *argv[])
 			 * or directories and this is post-order of the
 			 * root of a traversal, display the total.
 			 */
-			if (listdirs ||
-			    (!listfiles && p->fts_level == FTS_ROOTLEVEL)) {
+			if (p->fts_level <= maxdepth)
 				prtout((quad_t)howmany(p->fts_number,
 				    (unsigned long)blocksize), p->fts_path,
 				    hflag);
-			}
 			break;
 		case FTS_DC:			/* Ignore. */
 			break;
@@ -193,7 +193,7 @@ main(int argc, char *argv[])
 			 * If listing each file, or a non-directory file was
 			 * the root of a traversal, display the total.
 			 */
-			if (listfiles || p->fts_level == FTS_ROOTLEVEL)
+			if (listfiles && p->fts_level <= maxdepth)
 				prtout(howmany(p->fts_statp->st_blocks,
 				    blocksize), p->fts_path, hflag);
 			p->fts_parent->fts_number += p->fts_statp->st_blocks;
@@ -315,6 +315,6 @@ usage(void)
 {
 
 	(void)fprintf(stderr,
-		"usage: du [-a | -s] [-chkrx] [-H | -L | -P] [file ...]\n");
+	    "usage: du [-d depth] [-achkrsx] [-H | -L | -P] [file ...]\n");
 	exit(1);
 }