[PATCH] ash: setsid and TIOCSCTTY when enabling job control.

[Avery Pennarun]

Both calls will fail if we are already a process group leader, or the
process group leader is not us, or we already have a controlling terminal.
So basically these calls are harmless in the worst case, and get rid of the
annoying "can't access tty; job control turned off" problem in the best
case.  In other words, CTRL-C and CTRL-Z will work.

This makes busybox sh job control usable with "init=/bin/sh" on the Linux
kernel command line.
---
 shell/ash.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/shell/ash.c b/shell/ash.c
index 5671a52..5259dd2 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -3727,6 +3727,8 @@ setjobctl(int on)
 		if (fd < 0)
 			goto out;
 		/* fd is a tty at this point */
+		setsid();
+		ioctl(fd, TIOCSCTTY, 0);
 		close_on_exec_on(fd);
 		do { /* while we are in the background */
 			pgrp = tcgetpgrp(fd);
-- 
1.7.7.3