Add a new -o option to tell xargs(1) to reopen /dev/tty as stdin in

the child process, before executing the command.  This is very useful
when you do stuff like ``find ... | xargs interactive_application''.
Without -o, the application would inherit the pipe as its stdin, and
you thus lose any control over it.

This flag has been carefully chosen to not conflit with other options
of other xargs utilities like GNU xargs.

Reviewed by:	jmallett

2 files changed, 21 insertions, 5 deletions

diff --git a/usr.bin/xargs/xargs.1 b/usr.bin/xargs/xargs.1
index 7c2f70b..a36edd1 100644
--- a/usr.bin/xargs/xargs.1
+++ b/usr.bin/xargs/xargs.1
@@ -45,7 +45,7 @@
 .Nd "construct argument list(s) and execute utility"
 .Sh SYNOPSIS
 .Nm
-.Op Fl 0pt
+.Op Fl 0opt
 .Op Fl E Ar eofstr
 .Oo
 .Fl I Ar replstr
@@ -192,6 +192,13 @@ arguments remaining for the last invocation of
 The current default value for
 .Ar number
 is 5000.
+.It Fl o
+Reopen stdin as
+.Dq /dev/tty
+in the child process before executing the command.
+This is useful if you want
+.Nm
+to run an interactive application.
 .It Fl P Ar maxprocs
 Parallel mode: run at most
 .Ar maxprocs
@@ -287,7 +294,7 @@ utility is expected to be
 .St -p1003.2
 compliant.
 The
-.Fl J , P
+.Fl J , o , P
 and
 .Fl R
 options are non-standard
diff --git a/usr.bin/xargs/xargs.c b/usr.bin/xargs/xargs.c
index ec15af7..5e6c2b4 100644
--- a/usr.bin/xargs/xargs.c
+++ b/usr.bin/xargs/xargs.c
@@ -56,6 +56,7 @@ __FBSDID("$FreeBSD$");
 
 #include <err.h>
 #include <errno.h>
+#include <fcntl.h>
 #if (__FreeBSD_version >= 450002 && __FreeBSD_version < 500000) || \
     __FreeBSD_version >= 500017
 #include <langinfo.h>
@@ -82,7 +83,7 @@ static char echo[] = _PATH_ECHO;
 static char **av, **bxp, **ep, **exp, **xp;
 static char *argp, *bbp, *ebp, *inpline, *p, *replstr;
 static const char *eofstr;
-static int count, insingle, indouble, pflag, tflag, Rflag, rval, zflag;
+static int count, insingle, indouble, oflag, pflag, tflag, Rflag, rval, zflag;
 static int cnt, Iflag, jfound, Lflag, wasquoted, xflag;
 static int curprocs, maxprocs;
 
@@ -127,7 +128,7 @@ main(int argc, char *argv[])
 		nline -= strlen(*ep++) + 1 + sizeof(*ep);
 	}
 	maxprocs = 1;
-	while ((ch = getopt(argc, argv, "0E:I:J:L:n:P:pR:s:tx")) != -1)
+	while ((ch = getopt(argc, argv, "0E:I:J:L:n:oP:pR:s:tx")) != -1)
 		switch(ch) {
 		case 'E':
 			eofstr = optarg;
@@ -151,6 +152,9 @@ main(int argc, char *argv[])
 			if ((nargs = atoi(optarg)) <= 0)
 				errx(1, "illegal argument count");
 			break;
+		case 'o':
+			oflag = 1;
+			break;
 		case 'P':
 			if ((maxprocs = atoi(optarg)) <= 0)
 				errx(1, "max. processes must be >0");
@@ -522,6 +526,11 @@ exec:
 	case -1:
 		err(1, "vfork");
 	case 0:
+		if (oflag) {
+			close(0);
+			if (open("/dev/tty", O_RDONLY) == -1)
+				err(1, "open");
+		}
 		execvp(argv[0], argv);
 		childerr = errno;
 		_exit(1);
@@ -595,7 +604,7 @@ static void
 usage(void)
 {
 	fprintf(stderr,
-"usage: xargs [-0pt] [-E eofstr] [-I replstr [-R replacements]] [-J replstr]\n"
+"usage: xargs [-0opt] [-E eofstr] [-I replstr [-R replacements]] [-J replstr]\n"
 "             [-L number] [-n number [-x]] [-P maxprocs] [-s size]\n"
 "             [utility [argument ...]]\n");
 	exit(1);