[PATCH 20/75] pty: simplify resize

Alan Cox
2009-01-02T13:43:02Z

From: Alan Cox <alan@redhat.com>

We have special case logic for resizing pty/tty pairs. We also have a per
driver resize method so for the pty case we should use it.

Signed-off-by: Alan Cox <alan@redhat.com>
---

drivers/char/hvc_console.c | 2 +-
drivers/char/pty.c | 54 +++++++++++++++++++++++++++++++++++++++++++-
drivers/char/tty_io.c | 31 +++++++++----------------
drivers/char/vt.c | 14 +++++------
include/linux/tty.h | 3 +-
include/linux/tty_driver.h | 6 ++---
6 files changed, 74 insertions(+), 36 deletions(-)

diff --git a/drivers/char/hvc_console.c b/drivers/char/hvc_console.c
index 0587b66..5a8a4c2 100644
--- a/drivers/char/hvc_console.c
+++ b/drivers/char/hvc_console.c
@@ -529,7 +529,7 @@ static void hvc_set_winsz(struct work_struct *work)
tty = tty_kref_get(hp->tty);
spin_unlock_irqrestore(&hp->lock, hvc_flags);

- tty_do_resize(tty, tty, &ws);
+ tty_do_resize(tty, &ws);
tty_kref_put(tty);
}

diff --git a/drivers/char/pty.c b/drivers/char/pty.c
index 6d45827..b5daaaa 100644
--- a/drivers/char/pty.c
+++ b/drivers/char/pty.c
@@ -230,6 +230,55 @@ static void pty_set_termios(struct tty_struct *tty,
tty->termios->c_cflag |= (CS8 | CREAD);
}

+/**
+ * pty_do_resize - resize event
+ * @tty: tty being resized
+ * @real_tty: real tty (not the same as tty if using a pty/tty pair)
+ * @rows: rows (character)
+ * @cols: cols (character)
+ *
+ * Update the termios variables and send the neccessary signals to
+ * peform a terminal resize correctly
+ */
+
+int pty_resize(struct tty_struct *tty, struct winsize *ws)
+{
+ struct pid *pgrp, *rpgrp;
+ unsigned long flags;
+ struct tty_struct *pty = tty->link;
+
+ /* For a PTY we need to lock the tty side */
+ mutex_lock(&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.
+ We need to lock these individually however. */
+
+ spin_lock_irqsave(&tty->ctrl_lock, flags);
+ pgrp = get_pid(tty->pgrp);
+ spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+
+ spin_lock_irqsave(&pty->ctrl_lock, flags);
+ rpgrp = get_pid(pty->pgrp);
+ spin_unlock_irqrestore(&pty->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;
+ pty->winsize = *ws; /* Never used so will go away soon */
+done:
+ mutex_unlock(&tty->termios_mutex);
+ return 0;
+}
+
static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
{
struct tty_struct *o_tty;
@@ -290,6 +339,7 @@ static const struct tty_operations pty_ops = {
.chars_in_buffer = pty_chars_in_buffer,
.unthrottle = pty_unthrottle,
.set_termios = pty_set_termios,
+ .resize = pty_resize
};

/* Traditional BSD devices */
@@ -319,6 +369,7 @@ static const struct tty_operations pty_ops_bsd = {
.unthrottle = pty_unthrottle,
.set_termios = pty_set_termios,
.ioctl = pty_bsd_ioctl,
+ .resize = pty_resize
};

static void __init legacy_pty_init(void)
@@ -561,7 +612,8 @@ static const struct tty_operations ptm_unix98_ops = {
.unthrottle = pty_unthrottle,
.set_termios = pty_set_termios,
.ioctl = pty_unix98_ioctl,
- .shutdown = pty_unix98_shutdown
+ .shutdown = pty_unix98_shutdown,
+ .resize = pty_resize
};

static const struct tty_operations pty_unix98_ops = {
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index 2a15af6..d33e5ab 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -2048,7 +2048,6 @@ static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
/**
* tty_do_resize - resize event
* @tty: tty being resized
- * @real_tty: real tty (not the same as tty if using a pty/tty pair)
* @rows: rows (character)
* @cols: cols (character)
*
@@ -2056,41 +2055,34 @@ static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
* peform a terminal resize correctly
*/

-int tty_do_resize(struct tty_struct *tty, struct tty_struct *real_tty,
- struct winsize *ws)
+int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
{
- struct pid *pgrp, *rpgrp;
+ struct pid *pgrp;
unsigned long flags;

- /* For a PTY we need to lock the tty side */
- mutex_lock(&real_tty->termios_mutex);
- if (!memcmp(ws, &real_tty->winsize, sizeof(*ws)))
+ /* Lock the tty */
+ mutex_lock(&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;
- real_tty->winsize = *ws;
done:
- mutex_unlock(&real_tty->termios_mutex);
+ mutex_unlock(&tty->termios_mutex);
return 0;
}

/**
* tiocswinsz - implement window size set ioctl
- * @tty; tty
+ * @tty; tty side of tty
* @arg: user buffer for result
*
* Copies the user idea of the window size to the kernel. Traditionally
@@ -2103,17 +2095,16 @@ done:
* then calls into the default method.
*/

-static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty,
- struct winsize __user *arg)
+static int tiocswinsz(struct tty_struct *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);
+ return tty->ops->resize(tty, &tmp_ws);
else
- return tty_do_resize(tty, real_tty, &tmp_ws);
+ return tty_do_resize(tty, &tmp_ws);
}

/**
@@ -2538,7 +2529,7 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
case TIOCGWINSZ:
return tiocgwinsz(real_tty, p);
case TIOCSWINSZ:
- return tiocswinsz(tty, real_tty, p);
+ return tiocswinsz(real_tty, p);
case TIOCCONS:
return real_tty != tty ? -EINVAL : tioccons(file);
case FIONBIO:
diff --git a/drivers/char/vt.c b/drivers/char/vt.c
index 639e126..8001421 100644
--- a/drivers/char/vt.c
+++ b/drivers/char/vt.c
@@ -819,8 +819,8 @@ static inline int resize_screen(struct vc_data *vc, int width, int height,
* ctrl_lock of the tty IFF a tty is passed.
*/

-static int vc_do_resize(struct tty_struct *tty, struct tty_struct *real_tty,
- struct vc_data *vc, unsigned int cols, unsigned int lines)
+static int vc_do_resize(struct tty_struct *tty, struct vc_data *vc,
+ unsigned int cols, unsigned int lines)
{
unsigned long old_origin, new_origin, new_scr_end, rlth, rrem, err = 0;
unsigned int old_cols, old_rows, old_row_size, old_screen_size;
@@ -932,7 +932,7 @@ static int vc_do_resize(struct tty_struct *tty, struct tty_struct *real_tty,
ws.ws_row = vc->vc_rows;
ws.ws_col = vc->vc_cols;
ws.ws_ypixel = vc->vc_scan_lines;
- tty_do_resize(tty, real_tty, &ws);
+ tty_do_resize(tty, &ws);
}

if (CON_IS_VISIBLE(vc))
@@ -954,13 +954,12 @@ static int vc_do_resize(struct tty_struct *tty, struct tty_struct *real_tty,

int vc_resize(struct vc_data *vc, unsigned int cols, unsigned int rows)
{
- return vc_do_resize(vc->vc_tty, vc->vc_tty, vc, cols, rows);
+ return vc_do_resize(vc->vc_tty, vc, cols, rows);
}

/**
* vt_resize - resize a VT
* @tty: tty to resize
- * @real_tty: tty if a pty/tty pair
* @ws: winsize attributes
*
* Resize a virtual terminal. This is called by the tty layer as we
@@ -971,14 +970,13 @@ int vc_resize(struct vc_data *vc, unsigned int cols, unsigned int rows)
* termios_mutex and the tty ctrl_lock in that order.
*/

-int vt_resize(struct tty_struct *tty, struct tty_struct *real_tty,
- struct winsize *ws)
+int vt_resize(struct tty_struct *tty, struct winsize *ws)
{
struct vc_data *vc = tty->driver_data;
int ret;

acquire_console_sem();
- ret = vc_do_resize(tty, real_tty, vc, ws->ws_col, ws->ws_row);
+ ret = vc_do_resize(tty, vc, ws->ws_col, ws->ws_row);
release_console_sem();
return ret;
}
diff --git a/include/linux/tty.h b/include/linux/tty.h
index dfc77de..f881697 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -360,8 +360,7 @@ extern int tty_write_room(struct tty_struct *tty);
extern void tty_driver_flush_buffer(struct tty_struct *tty);
extern void tty_throttle(struct tty_struct *tty);
extern void tty_unthrottle(struct tty_struct *tty);
-extern int tty_do_resize(struct tty_struct *tty, struct tty_struct *real_tty,
- struct winsize *ws);
+extern int tty_do_resize(struct tty_struct *tty, struct winsize *ws);
extern void tty_shutdown(struct tty_struct *tty);
extern void tty_free_termios(struct tty_struct *tty);
extern int is_current_pgrp_orphaned(void);
diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h
index 78416b9..08e0883 100644
--- a/include/linux/tty_driver.h
+++ b/include/linux/tty_driver.h
@@ -196,8 +196,7 @@
* Optional: If not provided then the write method is called under
* the atomic write lock to keep it serialized with the ldisc.
*
- * int (*resize)(struct tty_struct *tty, struct tty_struct *real_tty,
- * unsigned int rows, unsigned int cols);
+ * int (*resize)(struct tty_struct *tty, struct winsize *ws)
*
* Called when a termios request is issued which changes the
* requested terminal geometry.
@@ -258,8 +257,7 @@ struct tty_operations {
int (*tiocmget)(struct tty_struct *tty, struct file *file);
int (*tiocmset)(struct tty_struct *tty, struct file *file,
unsigned int set, unsigned int clear);
- int (*resize)(struct tty_struct *tty, struct tty_struct *real_tty,
- struct winsize *ws);
+ int (*resize)(struct tty_struct *tty, struct winsize *ws);
int (*set_termiox)(struct tty_struct *tty, struct termiox *tnew);
#ifdef CONFIG_CONSOLE_POLL
int (*poll_init)(struct tty_driver *driver, int line, char *options);