Re: [PATCH 0/4] SIGWINCH problem with terminal apps still alive

["Adam Tlałka" <atlka@pg.gda.pl>]

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> Hello,
> 
> I am sending sligtly corrected patch.
> In case of ioctl(,TIOCSWINSZ,) on pty side we should send signal to
> master side too. I've tested it on modified unix putty version
> and it works properly.
> 
> Signed-off-by: Adam Tla/lka <atlka@pg.gda.pl>
> 
> Maybe we could optimize code more and not call 
> get_pid() and put_pid() if they are not needed - in case
> where there is no master/slave pair.

Not it is after small changes and proper path in patch.

Signed-off-by: Adam Tla/lka <atlka@pg.gda.pl>

Regards

-- 
Adam Tlałka       mailto:atlka@pg.gda.pl    ^v^ ^v^ ^v^
System  & Network Administration Group       - - - ~~~~~~
Computer Center, Gdańsk University of Technology, Poland

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--- drivers/char/tty_io_orig.c	2008-10-10 05:37:30.000000000 +0200
+++ drivers/char/tty_io.c	2008-10-14 15:58:54.000000000 +0200
@@ -2522,29 +2522,32 @@ int tty_do_resize(struct tty_struct *tty
 	struct pid *pgrp, *rpgrp;
 	unsigned long flags;
 
-	/* For a PTY we need to lock the tty side */
+        /* in case of resize ioctl on slave */
+	if ((tty == real_tty) && (tty->driver->type == TTY_DRIVER_TYPE_PTY))
+		tty = tty->link;
+	
+	/* for a PTY we need to lock the tty side */
 	mutex_lock(&real_tty->termios_mutex);
-	if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
-		goto done;
-	/* Get the PID values and reference them so we can
-	   avoid holding the tty ctrl lock while sending signals */
-	spin_lock_irqsave(&tty->ctrl_lock, flags);
-	pgrp = get_pid(tty->pgrp);
-	rpgrp = get_pid(real_tty->pgrp);
-	spin_unlock_irqrestore(&tty->ctrl_lock, flags);
-
-	if (pgrp)
-		kill_pgrp(pgrp, SIGWINCH, 1);
-	if (rpgrp != pgrp && rpgrp)
-		kill_pgrp(rpgrp, SIGWINCH, 1);
-
-	put_pid(pgrp);
-	put_pid(rpgrp);
-
-	tty->winsize = *ws;
+	flags = memcmp(ws, &real_tty->winsize, sizeof(*ws));
 	real_tty->winsize = *ws;
-done:
 	mutex_unlock(&real_tty->termios_mutex);
+	if (flags){
+		/* Get the PID values and reference them so we can
+		 avoid holding the tty ctrl lock while sending signals */
+		spin_lock_irqsave(&tty->ctrl_lock, flags);
+		pgrp =  get_pid(tty->pgrp);
+		rpgrp = get_pid(real_tty->pgrp);
+		spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+		if (pgrp){
+			kill_pgrp(pgrp, SIGWINCH, 1);
+			put_pid(pgrp);
+		}
+		if (rpgrp != pgrp && rpgrp){
+			kill_pgrp(rpgrp, SIGWINCH, 1);
+			put_pid(rpgrp);
+		}
+	}
+	
 	return 0;
 }
 
@@ -2996,7 +2999,7 @@ long tty_ioctl(struct file *file, unsign
 	case TIOCSTI:
 		return tiocsti(tty, p);
 	case TIOCGWINSZ:
-		return tiocgwinsz(tty, p);
+		return tiocgwinsz(real_tty, p);
 	case TIOCSWINSZ:
 		return tiocswinsz(tty, real_tty, p);
 	case TIOCCONS: