Make xargs run [utility] program even when zero arguements are provided,

makes xargs POSIX compliant.

Original diff from jason@, better diff provided by millert@

Resolves PR 4262

ok deraadt@ millert@

2 files changed, 20 insertions, 9 deletions

diff --git a/usr.bin/xargs/xargs.1 b/usr.bin/xargs/xargs.1
index 8fb7163e0e8..f632998df16 100644
--- a/usr.bin/xargs/xargs.1
+++ b/usr.bin/xargs/xargs.1
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: xargs.1,v 1.13 2003/06/12 17:55:01 jmc Exp $
+.\"	$OpenBSD: xargs.1,v 1.14 2005/09/10 23:00:29 brad Exp $
 .\"	$FreeBSD: xargs.1,v 1.30 2003/05/21 21:07:28 ru Exp $$
 .\"
 .\" Copyright (c) 1990, 1991, 1993
@@ -43,7 +43,7 @@
 .Sh SYNOPSIS
 .Nm xargs
 .Bk -words
-.Op Fl 0opt
+.Op Fl 0oprt
 .Op Fl E Ar eofstr
 .Oo
 .Fl I Ar replstr
@@ -74,7 +74,8 @@ upon each invocation, followed by some number of the arguments read
 from standard input.
 The
 .Ar utility
-is repeatedly executed until standard input is exhausted.
+is repeatedly executed one or more times until standard input
+is exhausted.
 .Pp
 Spaces, tabs and newlines may be embedded in arguments using single
 .Pq Ql '
@@ -222,6 +223,10 @@ will do replacement in.
 If
 .Ar replacements
 is negative, the number of arguments in which to replace is unbounded.
+.It Fl r
+Do not run the command if there are no arguments.
+Normally the command is executed at least once
+even if there are no arguments.
 .It Fl s Ar size
 Set the maximum number of bytes for the command line length provided to
 .Ar utility .
@@ -311,9 +316,9 @@ utility is expected to be
 .St -p1003.2
 compliant.
 The
-.Fl J , o , P
+.Fl J , o , P , R
 and
-.Fl R
+.Fl r
 options are non-standard
 extensions which may not be available on other operating systems.
 .Pp
diff --git a/usr.bin/xargs/xargs.c b/usr.bin/xargs/xargs.c
index 6b3ec60bfad..e6a7cd330a3 100644
--- a/usr.bin/xargs/xargs.c
+++ b/usr.bin/xargs/xargs.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: xargs.c,v 1.20 2005/06/20 18:52:19 millert Exp $	*/
+/*	$OpenBSD: xargs.c,v 1.21 2005/09/10 23:00:29 brad Exp $	*/
 /*	$FreeBSD: xargs.c,v 1.51 2003/05/03 19:09:11 obrien Exp $	*/
 
 /*-
@@ -45,7 +45,7 @@ static const char copyright[] =
 #if 0
 static const char sccsid[] = "@(#)xargs.c	8.1 (Berkeley) 6/6/93";
 #else
-static const char rcsid[] = "$OpenBSD: xargs.c,v 1.20 2005/06/20 18:52:19 millert Exp $";
+static const char rcsid[] = "$OpenBSD: xargs.c,v 1.21 2005/09/10 23:00:29 brad Exp $";
 #endif
 #endif /* not lint */
 
@@ -79,7 +79,7 @@ static char **av, **bxp, **ep, **endxp, **xp;
 static char *argp, *bbp, *ebp, *inpline, *p, *replstr;
 static const char *eofstr;
 static int count, insingle, indouble, oflag, pflag, tflag, Rflag, rval, zflag;
-static int cnt, Iflag, jfound, Lflag, wasquoted, xflag;
+static int cnt, Iflag, jfound, Lflag, wasquoted, xflag, runeof = 1;
 static int curprocs, maxprocs;
 static size_t inpsize;
 
@@ -122,7 +122,7 @@ main(int argc, char *argv[])
 		nline -= strlen(*ep++) + 1 + sizeof(*ep);
 	}
 	maxprocs = 1;
-	while ((ch = getopt(argc, argv, "0E:I:J:L:n:oP:pR:s:tx")) != -1)
+	while ((ch = getopt(argc, argv, "0E:I:J:L:n:oP:pR:rs:tx")) != -1)
 		switch (ch) {
 		case 'E':
 			eofstr = optarg;
@@ -156,6 +156,9 @@ main(int argc, char *argv[])
 		case 'p':
 			pflag = 1;
 			break;
+		case 'r':
+			runeof = 0;
+			break;
 		case 'R':
 			Rflag = strtol(optarg, &endptr, 10);
 			if (*endptr != '\0')
@@ -257,6 +260,8 @@ parse_input(int argc, char *argv[])
 	case EOF:
 		/* No arguments since last exec. */
 		if (p == bbp) {
+			if (runeof)
+				prerun(0, av);
 			waitchildren(*argv, 1);
 			exit(rval);
 		}
@@ -404,6 +409,7 @@ prerun(int argc, char *argv[])
 	int repls;
 
 	repls = Rflag;
+	runeof = 0;
 
 	if (argc == 0 || repls == 0) {
 		*xp = NULL;