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Date:      Thu, 25 Oct 2012 09:05:21 +0000 (UTC)
From:      Ed Schouten <ed@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r242078 - in head/sys: kern sys
Message-ID:  <201210250905.q9P95L2I017137@svn.freebsd.org>
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Author: ed
Date: Thu Oct 25 09:05:21 2012
New Revision: 242078
URL: http://svn.freebsd.org/changeset/base/242078

Log:
  Correct SIGTTIN handling.
  
  In the old TTY layer, SIGTTIN was correctly handled like this:
  
  	while (data should be read) {
  		send SIGTTIN if not foreground process group
  		read data
  	}
  
  In the new TTY layer, however, this behaviour was changed, based on a
  false interpretation of the standard:
  
  	send SIGTTIN if not foreground process group
  	while (data should be read) {
  		read data
  	}
  
  Correct this by pushing tty_wait_background() into the ttydisc_read_*()
  functions.
  
  Reported by:	koitsu
  PR:		kern/173010
  MFC after:	2 weeks

Modified:
  head/sys/kern/tty.c
  head/sys/kern/tty_ttydisc.c
  head/sys/sys/tty.h

Modified: head/sys/kern/tty.c
==============================================================================
--- head/sys/kern/tty.c	Thu Oct 25 09:02:21 2012	(r242077)
+++ head/sys/kern/tty.c	Thu Oct 25 09:05:21 2012	(r242078)
@@ -361,7 +361,7 @@ tty_is_ctty(struct tty *tp, struct proc 
 	return (p->p_session == tp->t_session && p->p_flag & P_CONTROLT);
 }
 
-static int
+int
 tty_wait_background(struct tty *tp, struct thread *td, int sig)
 {
 	struct proc *p = td->td_proc;
@@ -433,13 +433,6 @@ ttydev_read(struct cdev *dev, struct uio
 	error = ttydev_enter(tp);
 	if (error)
 		goto done;
-
-	error = tty_wait_background(tp, curthread, SIGTTIN);
-	if (error) {
-		tty_unlock(tp);
-		goto done;
-	}
-
 	error = ttydisc_read(tp, uio, ioflag);
 	tty_unlock(tp);
 

Modified: head/sys/kern/tty_ttydisc.c
==============================================================================
--- head/sys/kern/tty_ttydisc.c	Thu Oct 25 09:02:21 2012	(r242077)
+++ head/sys/kern/tty_ttydisc.c	Thu Oct 25 09:05:21 2012	(r242078)
@@ -126,6 +126,10 @@ ttydisc_read_canonical(struct tty *tp, s
 	breakc[n] = '\0';
 
 	do {
+		error = tty_wait_background(tp, curthread, SIGTTIN);
+		if (error)
+			return (error);
+
 		/*
 		 * Quite a tricky case: unlike the old TTY
 		 * implementation, this implementation copies data back
@@ -192,6 +196,10 @@ ttydisc_read_raw_no_timer(struct tty *tp
 	 */
 
 	for (;;) {
+		error = tty_wait_background(tp, curthread, SIGTTIN);
+		if (error)
+			return (error);
+
 		error = ttyinq_read_uio(&tp->t_inq, tp, uio,
 		    uio->uio_resid, 0);
 		if (error)
@@ -229,6 +237,10 @@ ttydisc_read_raw_read_timer(struct tty *
 	timevaladd(&end, &now);
 
 	for (;;) {
+		error = tty_wait_background(tp, curthread, SIGTTIN);
+		if (error)
+			return (error);
+
 		error = ttyinq_read_uio(&tp->t_inq, tp, uio,
 		    uio->uio_resid, 0);
 		if (error)
@@ -278,6 +290,10 @@ ttydisc_read_raw_interbyte_timer(struct 
 	 */
 
 	for (;;) {
+		error = tty_wait_background(tp, curthread, SIGTTIN);
+		if (error)
+			return (error);
+
 		error = ttyinq_read_uio(&tp->t_inq, tp, uio,
 		    uio->uio_resid, 0);
 		if (error)

Modified: head/sys/sys/tty.h
==============================================================================
--- head/sys/sys/tty.h	Thu Oct 25 09:02:21 2012	(r242077)
+++ head/sys/sys/tty.h	Thu Oct 25 09:05:21 2012	(r242078)
@@ -180,6 +180,7 @@ void	tty_signal_sessleader(struct tty *t
 void	tty_signal_pgrp(struct tty *tp, int signal);
 /* Waking up readers/writers. */
 int	tty_wait(struct tty *tp, struct cv *cv);
+int	tty_wait_background(struct tty *tp, struct thread *td, int sig);
 int	tty_timedwait(struct tty *tp, struct cv *cv, int timo);
 void	tty_wakeup(struct tty *tp, int flags);

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