From 8c9a9dd0fa3a269d380eaae2dc1bee39e865fae1 Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Fri, 15 Aug 2008 10:39:38 +0100 Subject: tty: remove resize window special case This moves it to being a tty operation. That removes special cases and now also means that resize can be picked up by um and other non vt consoles which may have a resize operation. Signed-off-by: Alan Cox Signed-off-by: Linus Torvalds --- drivers/char/tty_io.c | 72 ++++++++++++++++++++++++++++----------------------- 1 file changed, 40 insertions(+), 32 deletions(-) (limited to 'drivers/char/tty_io.c') diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index 0e6866fe0f9..a27160ba21d 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -2496,45 +2496,25 @@ static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg) } /** - * tiocswinsz - implement window size set ioctl - * @tty; tty - * @arg: user buffer for result + * tty_do_resize - resize event + * @tty: tty being resized + * @real_tty: real tty (if using a pty/tty pair) + * @rows: rows (character) + * @cols: cols (character) * - * Copies the user idea of the window size to the kernel. Traditionally - * this is just advisory information but for the Linux console it - * actually has driver level meaning and triggers a VC resize. - * - * Locking: - * Called function use the console_sem is used to ensure we do - * not try and resize the console twice at once. - * The tty->termios_mutex is used to ensure we don't double - * resize and get confused. Lock order - tty->termios_mutex before - * console sem + * Update the termios variables and send the neccessary signals to + * peform a terminal resize correctly */ -static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty, - struct winsize __user *arg) +int tty_do_resize(struct tty_struct *tty, struct tty_struct *real_tty, + struct winsize *ws) { - struct winsize tmp_ws; struct pid *pgrp, *rpgrp; unsigned long flags; - if (copy_from_user(&tmp_ws, arg, sizeof(*arg))) - return -EFAULT; - mutex_lock(&tty->termios_mutex); - if (!memcmp(&tmp_ws, &tty->winsize, sizeof(*arg))) + if (!memcmp(ws, &tty->winsize, sizeof(*ws))) goto done; - -#ifdef CONFIG_VT - if (tty->driver->type == TTY_DRIVER_TYPE_CONSOLE) { - if (vc_lock_resize(tty->driver_data, tmp_ws.ws_col, - tmp_ws.ws_row)) { - mutex_unlock(&tty->termios_mutex); - return -ENXIO; - } - } -#endif /* 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); @@ -2550,13 +2530,41 @@ static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty, put_pid(pgrp); put_pid(rpgrp); - tty->winsize = tmp_ws; - real_tty->winsize = tmp_ws; + tty->winsize = *ws; + real_tty->winsize = *ws; done: mutex_unlock(&tty->termios_mutex); return 0; } +/** + * tiocswinsz - implement window size set ioctl + * @tty; tty + * @arg: user buffer for result + * + * Copies the user idea of the window size to the kernel. Traditionally + * this is just advisory information but for the Linux console it + * actually has driver level meaning and triggers a VC resize. + * + * Locking: + * Driver dependant. The default do_resize method takes the + * tty termios mutex and ctrl_lock. The console takes its own lock + * then calls into the default method. + */ + +static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty, + struct winsize __user *arg) +{ + struct winsize tmp_ws; + if (copy_from_user(&tmp_ws, arg, sizeof(*arg))) + return -EFAULT; + + if (tty->ops->resize) + return tty->ops->resize(tty, real_tty, &tmp_ws); + else + return tty_do_resize(tty, real_tty, &tmp_ws); +} + /** * tioccons - allow admin to move logical console * @file: the file to become console -- cgit v1.2.3 From a152db71d962f405f7e9be5c818bddf6d1be50a7 Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Tue, 26 Aug 2008 19:55:58 +0100 Subject: tty: Fix termios tty window resize race with pty/tty pair Kanru Chen posted a patch versus the old code which deals with the case where you resize the pty side of a pty/tty pair. In that situation the termios data is updated for both pty and tty but the locks are not held for the right side. This implements the fix differently against the updated tty code. Patch by self but the hard bit (noticing and fixing the bug) is thanks to Kanru Chen. Signed-off-by: Alan Cox Signed-off-by: Linus Torvalds --- drivers/char/tty_io.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'drivers/char/tty_io.c') diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index a27160ba21d..daeb8f76697 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -2498,7 +2498,7 @@ static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg) /** * tty_do_resize - resize event * @tty: tty being resized - * @real_tty: real tty (if using a pty/tty pair) + * @real_tty: real tty (not the same as tty if using a pty/tty pair) * @rows: rows (character) * @cols: cols (character) * @@ -2512,7 +2512,8 @@ int tty_do_resize(struct tty_struct *tty, struct tty_struct *real_tty, struct pid *pgrp, *rpgrp; unsigned long flags; - mutex_lock(&tty->termios_mutex); + /* 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 @@ -2533,7 +2534,7 @@ int tty_do_resize(struct tty_struct *tty, struct tty_struct *real_tty, tty->winsize = *ws; real_tty->winsize = *ws; done: - mutex_unlock(&tty->termios_mutex); + mutex_unlock(&real_tty->termios_mutex); return 0; } -- cgit v1.2.3