- Use _PATH_TTY and _PATH_DEVNULL macros.

- Don't fail if we can't open /dev/null since this can happen if
  xargs is jail'ed or chroot'ed.

These fixes were submitted by Todd Miller from the OpenBSD project.
There was one problem in those fixes that broke -o, which is corrected
here and should be committed to the OpenBSD repo by Todd soon.

MFC in:	3 days

1 files changed, 9 insertions, 5 deletions

diff --git a/usr.bin/xargs/xargs.c b/usr.bin/xargs/xargs.c
index 77f08eb..227d9f5 100644
--- a/usr.bin/xargs/xargs.c
+++ b/usr.bin/xargs/xargs.c
@@ -483,6 +483,7 @@ static void
 run(char **argv)
 {
 	pid_t pid;
+	int fd;
 	char **avec;
 
 	/*
@@ -521,13 +522,16 @@ exec:
 	case -1:
 		err(1, "vfork");
 	case 0:
-		close(0);
 		if (oflag) {
-			if (open("/dev/tty", O_RDONLY) == -1)
-				err(1, "open /dev/tty");
+			if ((fd = open(_PATH_TTY, O_RDONLY)) == -1)
+				err(1, "can't open /dev/tty");
 		} else {
-			if (open("/dev/null", O_RDONLY) == -1)
-				err(1, "open /dev/null");
+			fd = open(_PATH_DEVNULL, O_RDONLY);
+		}
+		if (fd > STDIN_FILENO) {
+			if (dup2(fd, STDIN_FILENO) != 0)
+				err(1, "can't dup2 to stdin");
+			close(fd);
 		}
 		execvp(argv[0], argv);
 		childerr = errno;