static void change_termios(struct tty_struct * tty, struct termios * new_termios)
{
int canon_change;
struct termios old_termios = *tty->termios;
struct tty_ldisc *ld;
/*
* Perform the actual termios internal changes under lock.
*/
/* FIXME: we need to decide on some locking/ordering semantics
for the set_termios notification eventually */
down(&tty->termios_sem);
*tty->termios = *new_termios;
unset_locked_termios(tty->termios, &old_termios, tty->termios_locked);
canon_change = (old_termios.c_lflag ^ tty->termios->c_lflag) & ICANON;
if (canon_change) {
memset(&tty->read_flags, 0, sizeof tty->read_flags);
tty->canon_head = tty->read_tail;
tty->canon_data = 0;
tty->erasing = 0;
}
if (canon_change && !L_ICANON(tty) && tty->read_cnt)
/* Get characters left over from canonical mode. */
wake_up_interruptible(&tty->read_wait);
/* See if packet mode change of state. */
if (tty->link && tty->link->packet) {
int old_flow = ((old_termios.c_iflag & IXON) &&
(old_termios.c_cc[VSTOP] == '\023') &&
(old_termios.c_cc[VSTART] == '\021'));
int new_flow = (I_IXON(tty) &&
STOP_CHAR(tty) == '\023' &&
START_CHAR(tty) == '\021');
if (old_flow != new_flow) {
tty->ctrl_status &= ~(TIOCPKT_DOSTOP | TIOCPKT_NOSTOP);
if (new_flow)
tty->ctrl_status |= TIOCPKT_DOSTOP;
else
tty->ctrl_status |= TIOCPKT_NOSTOP;
wake_up_interruptible(&tty->link->read_wait);
}
}
if (tty->driver->set_termios)
(*tty->driver->set_termios)(tty, &old_termios);
ld = tty_ldisc_ref(tty);
if (ld != NULL) {
if (ld->set_termios)
(ld->set_termios)(tty, &old_termios);
tty_ldisc_deref(ld);
}
up(&tty->termios_sem);
}
/* Insert the contents of the selection buffer into the
* queue of the tty associated with the current console.
* Invoked by ioctl().
*/
int paste_selection(struct tty_struct *tty)
{
struct vt_struct *vt = (struct vt_struct *) tty->driver_data;
int pasted = 0, count;
struct tty_ldisc *ld;
DECLARE_WAITQUEUE(wait, current);
acquire_console_sem();
poke_blanked_console();
release_console_sem();
ld = tty_ldisc_ref_wait(tty);
add_wait_queue(&vt->paste_wait, &wait);
while (sel_buffer && sel_buffer_lth > pasted) {
set_current_state(TASK_INTERRUPTIBLE);
if (test_bit(TTY_THROTTLED, &tty->flags)) {
schedule();
continue;
}
count = sel_buffer_lth - pasted;
count = min(count, tty->ldisc.receive_room(tty));
tty->ldisc.receive_buf(tty, sel_buffer + pasted, NULL, count);
pasted += count;
}
remove_wait_queue(&vt->paste_wait, &wait);
current->state = TASK_RUNNING;
tty_ldisc_deref(ld);
return 0;
}
void uart_handle_dcd_change(struct uart_port *uport, unsigned int status)
{
struct uart_state *state = uport->state;
struct tty_port *port = &state->port;
struct tty_ldisc *ld = tty_ldisc_ref(port->tty);
struct pps_event_time ts;
if (ld && ld->ops->dcd_change)
pps_get_ts(&ts);
uport->icount.dcd++;
#ifdef CONFIG_HARD_PPS
if ((uport->flags & UPF_HARDPPS_CD) && status)
hardpps();
#endif
if (port->flags & ASYNC_CHECK_CD) {
if (status)
wake_up_interruptible(&port->open_wait);
else if (port->tty)
tty_hangup(port->tty);
}
if (ld && ld->ops->dcd_change)
ld->ops->dcd_change(port->tty, status, &ts);
if (ld)
tty_ldisc_deref(ld);
}
void tty_ldisc_hangup(struct tty_struct *tty)
{
struct tty_ldisc *ld;
int reset = tty->driver->flags & TTY_DRIVER_RESET_TERMIOS;
int err = 0;
/*
* FIXME! What are the locking issues here? This may me overdoing
* things... This question is especially important now that we've
* removed the irqlock.
*/
ld = tty_ldisc_ref(tty);
if (ld != NULL) {
/* We may have no line discipline at this point */
if (ld->ops->flush_buffer)
ld->ops->flush_buffer(tty);
tty_driver_flush_buffer(tty);
if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) &&
ld->ops->write_wakeup)
ld->ops->write_wakeup(tty);
if (ld->ops->hangup)
ld->ops->hangup(tty);
tty_ldisc_deref(ld);
}
/*
* FIXME: Once we trust the LDISC code better we can wait here for
* ldisc completion and fix the driver call race
*/
wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
wake_up_interruptible_poll(&tty->read_wait, POLLIN);
/*
* Shutdown the current line discipline, and reset it to
* N_TTY if need be.
*
* Avoid racing set_ldisc or tty_ldisc_release
*/
mutex_lock(&tty->ldisc_mutex);
tty_ldisc_halt(tty);
/* At this point we have a closed ldisc and we want to
reopen it. We could defer this to the next open but
it means auditing a lot of other paths so this is
a FIXME */
if (tty->ldisc) { /* Not yet closed */
if (reset == 0) {
tty_ldisc_reinit(tty, tty->termios->c_line);
err = tty_ldisc_open(tty, tty->ldisc);
}
/* If the re-open fails or we reset then go to N_TTY. The
N_TTY open cannot fail */
if (reset || err) {
tty_ldisc_reinit(tty, N_TTY);
WARN_ON(tty_ldisc_open(tty, tty->ldisc));
}
tty_ldisc_enable(tty);
}
mutex_unlock(&tty->ldisc_mutex);
if (reset)
tty_reset_termios(tty);
}
static void flush_to_ldisc(struct work_struct *work)
{
struct tty_struct *tty =
container_of(work, struct tty_struct, buf.work);
unsigned long flags;
struct tty_ldisc *disc;
disc = tty_ldisc_ref(tty);
if (disc == NULL) /* !TTY_LDISC */
return;
spin_lock_irqsave(&tty->buf.lock, flags);
if (!test_and_set_bit(TTY_FLUSHING, &tty->flags)) {
struct tty_buffer *head;
while ((head = tty->buf.head) != NULL) {
int count;
char *char_buf;
unsigned char *flag_buf;
count = head->commit - head->read;
if (!count) {
if (head->next == NULL)
break;
tty->buf.head = head->next;
tty_buffer_free(tty, head);
continue;
}
/* Ldisc or user is trying to flush the buffers
we are feeding to the ldisc, stop feeding the
line discipline as we want to empty the queue */
if (test_bit(TTY_FLUSHPENDING, &tty->flags))
break;
if (!tty->receive_room)
break;
if (count > tty->receive_room)
count = tty->receive_room;
char_buf = head->char_buf_ptr + head->read;
flag_buf = head->flag_buf_ptr + head->read;
head->read += count;
spin_unlock_irqrestore(&tty->buf.lock, flags);
disc->ops->receive_buf(tty, char_buf,
flag_buf, count);
spin_lock_irqsave(&tty->buf.lock, flags);
}
clear_bit(TTY_FLUSHING, &tty->flags);
}
/* We may have a deferred request to flush the input buffer,
if so pull the chain under the lock and empty the queue */
if (test_bit(TTY_FLUSHPENDING, &tty->flags)) {
__tty_buffer_flush(tty);
clear_bit(TTY_FLUSHPENDING, &tty->flags);
wake_up(&tty->read_wait);
}
spin_unlock_irqrestore(&tty->buf.lock, flags);
tty_ldisc_deref(disc);
}
/**
* tty_set_termios - update termios values
* @tty: tty to update
* @new_termios: desired new value
*
* Perform updates to the termios values set on this terminal. There
* is a bit of layering violation here with n_tty in terms of the
* internal knowledge of this function.
*
* Locking: termios_mutex
*/
int tty_set_termios(struct tty_struct *tty, struct ktermios *new_termios)
{
struct ktermios old_termios;
struct tty_ldisc *ld;
unsigned long flags;
/*
* Perform the actual termios internal changes under lock.
*/
/* FIXME: we need to decide on some locking/ordering semantics
for the set_termios notification eventually */
mutex_lock(&tty->termios_mutex);
old_termios = *tty->termios;
*tty->termios = *new_termios;
unset_locked_termios(tty->termios, &old_termios, tty->termios_locked);
/* See if packet mode change of state. */
if (tty->link && tty->link->packet) {
int extproc = (old_termios.c_lflag & EXTPROC) |
(tty->termios->c_lflag & EXTPROC);
int old_flow = ((old_termios.c_iflag & IXON) &&
(old_termios.c_cc[VSTOP] == '\023') &&
(old_termios.c_cc[VSTART] == '\021'));
int new_flow = (I_IXON(tty) &&
STOP_CHAR(tty) == '\023' &&
START_CHAR(tty) == '\021');
if ((old_flow != new_flow) || extproc) {
spin_lock_irqsave(&tty->ctrl_lock, flags);
if (old_flow != new_flow) {
tty->ctrl_status &= ~(TIOCPKT_DOSTOP | TIOCPKT_NOSTOP);
if (new_flow)
tty->ctrl_status |= TIOCPKT_DOSTOP;
else
tty->ctrl_status |= TIOCPKT_NOSTOP;
}
if (extproc)
tty->ctrl_status |= TIOCPKT_IOCTL;
spin_unlock_irqrestore(&tty->ctrl_lock, flags);
wake_up_interruptible(&tty->link->read_wait);
}
}
if (tty->ops->set_termios)
(*tty->ops->set_termios)(tty, &old_termios);
else
tty_termios_copy_hw(tty->termios, &old_termios);
ld = tty_ldisc_ref(tty);
if (ld != NULL) {
if (ld->ops->set_termios)
(ld->ops->set_termios)(tty, &old_termios);
tty_ldisc_deref(ld);
}
mutex_unlock(&tty->termios_mutex);
return 0;
}
void tty_ldisc_flush(struct tty_struct *tty)
{
struct tty_ldisc *ld = tty_ldisc_ref(tty);
if (ld) {
if (ld->ops->flush_buffer)
ld->ops->flush_buffer(tty);
tty_ldisc_deref(ld);
}
tty_buffer_flush(tty);
}
static void pty_flush_buffer(struct tty_struct *tty)
{
struct tty_struct *to = tty->link;
struct tty_ldisc *ld;
if (!to)
return;
ld = tty_ldisc_ref(to);
tty_buffer_flush(to, ld);
if (ld)
tty_ldisc_deref(ld);
if (to->packet) {
spin_lock_irq(&tty->ctrl_lock);
tty->ctrl_status |= TIOCPKT_FLUSHWRITE;
wake_up_interruptible(&to->read_wait);
spin_unlock_irq(&tty->ctrl_lock);
}
}
/**
* usb_serial_handle_dcd_change - handle a change of carrier detect state
* @port: usb-serial port
* @tty: tty for the port
* @status: new carrier detect status, nonzero if active
*/
void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port,
struct tty_struct *tty, unsigned int status)
{
struct tty_port *port = &usb_port->port;
dev_dbg(&usb_port->dev, "%s - status %d\n", __func__, status);
if (tty) {
struct tty_ldisc *ld = tty_ldisc_ref(tty);
if (ld) {
if (ld->ops->dcd_change)
ld->ops->dcd_change(tty, status);
tty_ldisc_deref(ld);
}
}
if (status)
wake_up_interruptible(&port->open_wait);
else if (tty && !C_CLOCAL(tty))
tty_hangup(tty);
}
static int tty_port_default_receive_buf(struct tty_port *port,
const unsigned char *p,
const unsigned char *f, size_t count)
{
int ret;
struct tty_struct *tty;
struct tty_ldisc *disc;
tty = READ_ONCE(port->itty);
if (!tty)
return 0;
disc = tty_ldisc_ref(tty);
if (!disc)
return 0;
ret = tty_ldisc_receive_buf(disc, p, (char *)f, count);
tty_ldisc_deref(disc);
return ret;
}
static int set_termios(struct tty_struct * tty, void __user *arg, int opt)
{
struct termios tmp_termios;
struct tty_ldisc *ld;
int retval = tty_check_change(tty);
if (retval)
return retval;
if (opt & TERMIOS_TERMIO) {
memcpy(&tmp_termios, tty->termios, sizeof(struct termios));
if (user_termio_to_kernel_termios(&tmp_termios,
(struct termio __user *)arg))
return -EFAULT;
} else {
if (user_termios_to_kernel_termios(&tmp_termios,
(struct termios __user *)arg))
return -EFAULT;
}
ld = tty_ldisc_ref(tty);
if (ld != NULL) {
if ((opt & TERMIOS_FLUSH) && ld->flush_buffer)
ld->flush_buffer(tty);
tty_ldisc_deref(ld);
}
if (opt & TERMIOS_WAIT) {
tty_wait_until_sent(tty, 0);
if (signal_pending(current))
return -EINTR;
}
change_termios(tty, &tmp_termios);
return 0;
}
/** \<\<private\>\> Read function for TTY
* @TODO: Why is this copied here from kernel?
*
* @param *file - pointer to file we wanted to read from
* @param *buf - pointer to buffer in kernelspace witch will be filled with data
* @param count - buffer size
* @param *ppos - pointer to file offset
*
* @return Amount of bytes read or error
*/
static ssize_t proxyfs_tty_real_file_tty_read(struct file * file, char *buf, size_t count, loff_t *ppos)
{
int i;
struct tty_struct * tty;
struct inode *inode;
struct tty_ldisc *ld = NULL;
int state;
tty = (struct tty_struct *)file->private_data;
inode = file->f_path.dentry->d_inode;
//if (tty_paranoia_check(tty, inode, "tty_read"))
// return -EIO;
if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
return -EIO;
/* We not want to wait for the line discipline to sort out in this
situation */
ld = tty_ldisc_ref(tty);
if(ld){
lock_kernel();
if (ld->ops->read){
state = current->state;
i = (ld->ops->read)(tty,file,buf,count);
current->state = state;
}
else
i = -EIO;
tty_ldisc_deref(ld);
unlock_kernel();
if (i > 0)
inode->i_atime = current_fs_time(inode->i_sb);
return i;
}
else
return -EAGAIN;
}
void tty_ldisc_hangup(struct tty_struct *tty)
{
struct tty_ldisc *ld;
int reset = tty->driver->flags & TTY_DRIVER_RESET_TERMIOS;
int err = 0;
/*
* FIXME! What are the locking issues here? This may me overdoing
* things... This question is especially important now that we've
* removed the irqlock.
*/
ld = tty_ldisc_ref(tty);
if (ld != NULL) {
/* We may have no line discipline at this point */
if (ld->ops->flush_buffer)
ld->ops->flush_buffer(tty);
tty_driver_flush_buffer(tty);
if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) &&
ld->ops->write_wakeup)
ld->ops->write_wakeup(tty);
if (ld->ops->hangup)
ld->ops->hangup(tty);
tty_ldisc_deref(ld);
}
/*
* FIXME: Once we trust the LDISC code better we can wait here for
* ldisc completion and fix the driver call race
*/
wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
wake_up_interruptible_poll(&tty->read_wait, POLLIN);
/*
* Shutdown the current line discipline, and reset it to
* N_TTY if need be.
*
* Avoid racing set_ldisc or tty_ldisc_release
*/
mutex_lock(&tty->ldisc_mutex);
/*
* this is like tty_ldisc_halt, but we need to give up
* the BTM before calling cancel_work_sync, which may
* need to wait for another function taking the BTM
*/
clear_bit(TTY_LDISC, &tty->flags);
tty_unlock(tty);
cancel_work_sync(&tty->port->buf.work);
mutex_unlock(&tty->ldisc_mutex);
retry:
tty_lock(tty);
mutex_lock(&tty->ldisc_mutex);
/* At this point we have a closed ldisc and we want to
reopen it. We could defer this to the next open but
it means auditing a lot of other paths so this is
a FIXME */
if (tty->ldisc) { /* Not yet closed */
if (atomic_read(&tty->ldisc->users) != 1) {
char cur_n[TASK_COMM_LEN], tty_n[64];
long timeout = 3 * HZ;
tty_unlock(tty);
while (tty_ldisc_wait_idle(tty, timeout) == -EBUSY) {
timeout = MAX_SCHEDULE_TIMEOUT;
printk_ratelimited(KERN_WARNING
"%s: waiting (%s) for %s took too long, but we keep waiting...\n",
__func__, get_task_comm(cur_n, current),
tty_name(tty, tty_n));
}
mutex_unlock(&tty->ldisc_mutex);
goto retry;
}
if (reset == 0) {
if (!tty_ldisc_reinit(tty, tty->termios.c_line))
err = tty_ldisc_open(tty, tty->ldisc);
else
err = 1;
}
/* If the re-open fails or we reset then go to N_TTY. The
N_TTY open cannot fail */
if (reset || err) {
BUG_ON(tty_ldisc_reinit(tty, N_TTY));
WARN_ON(tty_ldisc_open(tty, tty->ldisc));
}
tty_ldisc_enable(tty);
}
mutex_unlock(&tty->ldisc_mutex);
if (reset)
tty_reset_termios(tty);
}
int tty_set_ldisc(struct tty_struct *tty, int ldisc)
{
int retval;
struct tty_ldisc o_ldisc, new_ldisc;
int work;
unsigned long flags;
struct tty_struct *o_tty;
restart:
/* This is a bit ugly for now but means we can break the 'ldisc
is part of the tty struct' assumption later */
retval = tty_ldisc_get(ldisc, &new_ldisc);
if (retval)
return retval;
/*
* Problem: What do we do if this blocks ?
*/
tty_wait_until_sent(tty, 0);
if (tty->ldisc.ops->num == ldisc) {
tty_ldisc_put(new_ldisc.ops);
return 0;
}
/*
* No more input please, we are switching. The new ldisc
* will update this value in the ldisc open function
*/
tty->receive_room = 0;
o_ldisc = tty->ldisc;
o_tty = tty->link;
/*
* Make sure we don't change while someone holds a
* reference to the line discipline. The TTY_LDISC bit
* prevents anyone taking a reference once it is clear.
* We need the lock to avoid racing reference takers.
*
* We must clear the TTY_LDISC bit here to avoid a livelock
* with a userspace app continually trying to use the tty in
* parallel to the change and re-referencing the tty.
*/
clear_bit(TTY_LDISC, &tty->flags);
if (o_tty)
clear_bit(TTY_LDISC, &o_tty->flags);
spin_lock_irqsave(&tty_ldisc_lock, flags);
if (tty->ldisc.refcount || (o_tty && o_tty->ldisc.refcount)) {
if (tty->ldisc.refcount) {
/* Free the new ldisc we grabbed. Must drop the lock
first. */
spin_unlock_irqrestore(&tty_ldisc_lock, flags);
tty_ldisc_put(new_ldisc.ops);
/*
* There are several reasons we may be busy, including
* random momentary I/O traffic. We must therefore
* retry. We could distinguish between blocking ops
* and retries if we made tty_ldisc_wait() smarter.
* That is up for discussion.
*/
if (wait_event_interruptible(tty_ldisc_wait, tty->ldisc.refcount == 0) < 0)
return -ERESTARTSYS;
goto restart;
}
if (o_tty && o_tty->ldisc.refcount) {
spin_unlock_irqrestore(&tty_ldisc_lock, flags);
tty_ldisc_put(o_tty->ldisc.ops);
if (wait_event_interruptible(tty_ldisc_wait, o_tty->ldisc.refcount == 0) < 0)
return -ERESTARTSYS;
goto restart;
}
}
/*
* If the TTY_LDISC bit is set, then we are racing against
* another ldisc change
*/
if (test_bit(TTY_LDISC_CHANGING, &tty->flags)) {
struct tty_ldisc *ld;
spin_unlock_irqrestore(&tty_ldisc_lock, flags);
tty_ldisc_put(new_ldisc.ops);
ld = tty_ldisc_ref_wait(tty);
tty_ldisc_deref(ld);
goto restart;
}
/*
* This flag is used to avoid two parallel ldisc changes. Once
* open and close are fine grained locked this may work better
* as a mutex shared with the open/close/hup paths
*/
set_bit(TTY_LDISC_CHANGING, &tty->flags);
if (o_tty)
set_bit(TTY_LDISC_CHANGING, &o_tty->flags);
spin_unlock_irqrestore(&tty_ldisc_lock, flags);
/*
* From this point on we know nobody has an ldisc
* usage reference, nor can they obtain one until
* we say so later on.
*/
work = cancel_delayed_work(&tty->buf.work);
/*
* Wait for ->hangup_work and ->buf.work handlers to terminate
* MUST NOT hold locks here.
*/
flush_scheduled_work();
/* Shutdown the current discipline. */
if (o_ldisc.ops->close)
(o_ldisc.ops->close)(tty);
/* Now set up the new line discipline. */
tty_ldisc_assign(tty, &new_ldisc);
tty_set_termios_ldisc(tty, ldisc);
if (new_ldisc.ops->open)
retval = (new_ldisc.ops->open)(tty);
if (retval < 0) {
tty_ldisc_put(new_ldisc.ops);
tty_ldisc_restore(tty, &o_ldisc);
}
/* At this point we hold a reference to the new ldisc and a
a reference to the old ldisc. If we ended up flipping back
to the existing ldisc we have two references to it */
if (tty->ldisc.ops->num != o_ldisc.ops->num && tty->ops->set_ldisc)
tty->ops->set_ldisc(tty);
tty_ldisc_put(o_ldisc.ops);
/*
* Allow ldisc referencing to occur as soon as the driver
* ldisc callback completes.
*/
tty_ldisc_enable(tty);
if (o_tty)
tty_ldisc_enable(o_tty);
/* Restart it in case no characters kick it off. Safe if
already running */
if (work)
schedule_delayed_work(&tty->buf.work, 1);
return retval;
}
int n_tty_ioctl(struct tty_struct * tty, struct file * file,
unsigned int cmd, unsigned long arg)
{
struct tty_struct * real_tty;
void __user *p = (void __user *)arg;
int retval;
struct tty_ldisc *ld;
if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
tty->driver->subtype == PTY_TYPE_MASTER)
real_tty = tty->link;
else
real_tty = tty;
switch (cmd) {
#ifdef TIOCGETP
case TIOCGETP:
return get_sgttyb(real_tty, (struct sgttyb __user *) arg);
case TIOCSETP:
case TIOCSETN:
return set_sgttyb(real_tty, (struct sgttyb __user *) arg);
#endif
#ifdef TIOCGETC
case TIOCGETC:
return get_tchars(real_tty, p);
case TIOCSETC:
return set_tchars(real_tty, p);
#endif
#ifdef TIOCGLTC
case TIOCGLTC:
return get_ltchars(real_tty, p);
case TIOCSLTC:
return set_ltchars(real_tty, p);
#endif
case TCGETS:
if (kernel_termios_to_user_termios((struct termios __user *)arg, real_tty->termios))
return -EFAULT;
return 0;
case TCSETSF:
return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT);
case TCSETSW:
return set_termios(real_tty, p, TERMIOS_WAIT);
case TCSETS:
return set_termios(real_tty, p, 0);
case TCGETA:
return get_termio(real_tty, p);
case TCSETAF:
return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT | TERMIOS_TERMIO);
case TCSETAW:
return set_termios(real_tty, p, TERMIOS_WAIT | TERMIOS_TERMIO);
case TCSETA:
return set_termios(real_tty, p, TERMIOS_TERMIO);
case TCXONC:
retval = tty_check_change(tty);
if (retval)
return retval;
switch (arg) {
case TCOOFF:
if (!tty->flow_stopped) {
tty->flow_stopped = 1;
stop_tty(tty);
}
break;
case TCOON:
if (tty->flow_stopped) {
tty->flow_stopped = 0;
start_tty(tty);
}
break;
case TCIOFF:
if (STOP_CHAR(tty) != __DISABLED_CHAR)
send_prio_char(tty, STOP_CHAR(tty));
break;
case TCION:
if (START_CHAR(tty) != __DISABLED_CHAR)
send_prio_char(tty, START_CHAR(tty));
break;
default:
return -EINVAL;
}
return 0;
case TCFLSH:
retval = tty_check_change(tty);
if (retval)
return retval;
ld = tty_ldisc_ref(tty);
switch (arg) {
case TCIFLUSH:
if (ld->flush_buffer)
ld->flush_buffer(tty);
break;
case TCIOFLUSH:
if (ld->flush_buffer)
ld->flush_buffer(tty);
/* fall through */
case TCOFLUSH:
if (tty->driver->flush_buffer)
tty->driver->flush_buffer(tty);
break;
default:
tty_ldisc_deref(ld);
return -EINVAL;
}
tty_ldisc_deref(ld);
return 0;
case TIOCOUTQ:
return put_user(tty->driver->chars_in_buffer ?
tty->driver->chars_in_buffer(tty) : 0,
(int __user *) arg);
case TIOCINQ:
retval = tty->read_cnt;
if (L_ICANON(tty))
retval = inq_canon(tty);
return put_user(retval, (unsigned int __user *) arg);
case TIOCGLCKTRMIOS:
if (kernel_termios_to_user_termios((struct termios __user *)arg, real_tty->termios_locked))
return -EFAULT;
return 0;
case TIOCSLCKTRMIOS:
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (user_termios_to_kernel_termios(real_tty->termios_locked, (struct termios __user *) arg))
return -EFAULT;
return 0;
case TIOCPKT:
{
int pktmode;
if (tty->driver->type != TTY_DRIVER_TYPE_PTY ||
tty->driver->subtype != PTY_TYPE_MASTER)
return -ENOTTY;
if (get_user(pktmode, (int __user *) arg))
return -EFAULT;
if (pktmode) {
if (!tty->packet) {
tty->packet = 1;
tty->link->ctrl_status = 0;
}
} else
tty->packet = 0;
return 0;
}
case TIOCGSOFTCAR:
return put_user(C_CLOCAL(tty) ? 1 : 0, (int __user *)arg);
case TIOCSSOFTCAR:
if (get_user(arg, (unsigned int __user *) arg))
return -EFAULT;
down(&tty->termios_sem);
tty->termios->c_cflag =
((tty->termios->c_cflag & ~CLOCAL) |
(arg ? CLOCAL : 0));
up(&tty->termios_sem);
return 0;
default:
return -ENOIOCTLCMD;
}
}
static void flush_to_ldisc(struct work_struct *work)
{
struct tty_struct *tty =
container_of(work, struct tty_struct, buf.work.work);
unsigned long flags;
struct tty_ldisc *disc;
disc = tty_ldisc_ref(tty);
if (disc == NULL) /* !TTY_LDISC */
return;
spin_lock_irqsave(&tty->buf.lock, flags);
if (!test_and_set_bit(TTY_FLUSHING, &tty->flags)) {
struct tty_buffer *head, *tail = tty->buf.tail;
int seen_tail = 0;
while ((head = tty->buf.head) != NULL) {
int count;
char *char_buf;
unsigned char *flag_buf;
count = head->commit - head->read;
if (!count) {
if (head->next == NULL)
break;
/*
There's a possibility tty might get new buffer
added during the unlock window below. We could
end up spinning in here forever hogging the CPU
completely. To avoid this let's have a rest each
time we processed the tail buffer.
*/
if (tail == head)
seen_tail = 1;
tty->buf.head = head->next;
tty_buffer_free(tty, head);
continue;
}
/* Ldisc or user is trying to flush the buffers
we are feeding to the ldisc, stop feeding the
line discipline as we want to empty the queue */
if (test_bit(TTY_FLUSHPENDING, &tty->flags))
break;
if (!tty->receive_room || seen_tail) {
schedule_delayed_work(&tty->buf.work, 1);
break;
}
if (count > tty->receive_room)
count = tty->receive_room;
char_buf = head->char_buf_ptr + head->read;
flag_buf = head->flag_buf_ptr + head->read;
head->read += count;
spin_unlock_irqrestore(&tty->buf.lock, flags);
disc->ops->receive_buf(tty, char_buf,
flag_buf, count);
spin_lock_irqsave(&tty->buf.lock, flags);
}
clear_bit(TTY_FLUSHING, &tty->flags);
}
/* We may have a deferred request to flush the input buffer,
if so pull the chain under the lock and empty the queue */
if (test_bit(TTY_FLUSHPENDING, &tty->flags)) {
__tty_buffer_flush(tty);
clear_bit(TTY_FLUSHPENDING, &tty->flags);
wake_up(&tty->read_wait);
}
spin_unlock_irqrestore(&tty->buf.lock, flags);
tty_ldisc_deref(disc);
}
void tty_ldisc_hangup(struct tty_struct *tty)
{
struct tty_ldisc *ld;
int reset = tty->driver->flags & TTY_DRIVER_RESET_TERMIOS;
int err = 0;
tty_ldisc_debug(tty, "closing ldisc: %p\n", tty->ldisc);
ld = tty_ldisc_ref(tty);
if (ld != NULL) {
if (ld->ops->flush_buffer)
ld->ops->flush_buffer(tty);
tty_driver_flush_buffer(tty);
if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) &&
ld->ops->write_wakeup)
ld->ops->write_wakeup(tty);
if (ld->ops->hangup)
ld->ops->hangup(tty);
tty_ldisc_deref(ld);
}
wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
wake_up_interruptible_poll(&tty->read_wait, POLLIN);
tty_unlock(tty);
/*
* Shutdown the current line discipline, and reset it to
* N_TTY if need be.
*
* Avoid racing set_ldisc or tty_ldisc_release
*/
tty_ldisc_lock_pair(tty, tty->link);
tty_lock(tty);
if (tty->ldisc) {
/* At this point we have a halted ldisc; we want to close it and
reopen a new ldisc. We could defer the reopen to the next
open but it means auditing a lot of other paths so this is
a FIXME */
if (reset == 0) {
if (!tty_ldisc_reinit(tty, tty->termios.c_line))
err = tty_ldisc_open(tty, tty->ldisc);
else
err = 1;
}
/* If the re-open fails or we reset then go to N_TTY. The
N_TTY open cannot fail */
if (reset || err) {
BUG_ON(tty_ldisc_reinit(tty, N_TTY));
WARN_ON(tty_ldisc_open(tty, tty->ldisc));
}
}
tty_ldisc_enable_pair(tty, tty->link);
if (reset)
tty_reset_termios(tty);
tty_ldisc_debug(tty, "re-opened ldisc: %p\n", tty->ldisc);
}
void tty_ldisc_hangup(struct tty_struct *tty)
{
struct tty_ldisc *ld;
int reset = tty->driver->flags & TTY_DRIVER_RESET_TERMIOS;
int err = 0;
ld = tty_ldisc_ref(tty);
if (ld != NULL) {
/* We may have no line discipline at this point */
if (ld->ops->flush_buffer)
ld->ops->flush_buffer(tty);
tty_driver_flush_buffer(tty);
if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) &&
ld->ops->write_wakeup)
ld->ops->write_wakeup(tty);
if (ld->ops->hangup)
ld->ops->hangup(tty);
tty_ldisc_deref(ld);
}
wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
wake_up_interruptible_poll(&tty->read_wait, POLLIN);
/*
* Shutdown the current line discipline, and reset it to
* N_TTY if need be.
*
* Avoid racing set_ldisc or tty_ldisc_release
*/
mutex_lock(&tty->ldisc_mutex);
/*
* this is like tty_ldisc_halt, but we need to give up
* the BTM before calling cancel_delayed_work_sync,
* which may need to wait for another function taking the BTM
*/
clear_bit(TTY_LDISC, &tty->flags);
tty_unlock();
cancel_delayed_work_sync(&tty->buf.work);
mutex_unlock(&tty->ldisc_mutex);
tty_lock();
mutex_lock(&tty->ldisc_mutex);
if (tty->ldisc) { /* Not yet closed */
if (reset == 0) {
if (!tty_ldisc_reinit(tty, tty->termios->c_line))
err = tty_ldisc_open(tty, tty->ldisc);
else
err = 1;
}
/* If the re-open fails or we reset then go to N_TTY. The
N_TTY open cannot fail */
if (reset || err) {
BUG_ON(tty_ldisc_reinit(tty, N_TTY));
WARN_ON(tty_ldisc_open(tty, tty->ldisc));
}
tty_ldisc_enable(tty);
}
mutex_unlock(&tty->ldisc_mutex);
if (reset)
tty_reset_termios(tty);
}
void jsm_input(struct jsm_channel *ch)
{
struct jsm_board *bd;
struct tty_struct *tp;
struct tty_ldisc *ld;
u32 rmask;
u16 head;
u16 tail;
int data_len;
unsigned long lock_flags;
int flip_len = 0;
int len = 0;
int n = 0;
int s = 0;
int i = 0;
jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "start\n");
if (!ch)
return;
tp = ch->uart_port.info->tty;
bd = ch->ch_bd;
if(!bd)
return;
spin_lock_irqsave(&ch->ch_lock, lock_flags);
/*
*Figure the number of characters in the buffer.
*Exit immediately if none.
*/
rmask = RQUEUEMASK;
head = ch->ch_r_head & rmask;
tail = ch->ch_r_tail & rmask;
data_len = (head - tail) & rmask;
if (data_len == 0) {
spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
return;
}
jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "start\n");
/*
*If the device is not open, or CREAD is off, flush
*input data and return immediately.
*/
if (!tp ||
!(tp->termios->c_cflag & CREAD) ) {
jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
"input. dropping %d bytes on port %d...\n", data_len, ch->ch_portnum);
ch->ch_r_head = tail;
/* Force queue flow control to be released, if needed */
jsm_check_queue_flow_control(ch);
spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
return;
}
/*
* If we are throttled, simply don't read any data.
*/
if (ch->ch_flags & CH_STOPI) {
spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
"Port %d throttled, not reading any data. head: %x tail: %x\n",
ch->ch_portnum, head, tail);
return;
}
jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "start 2\n");
/*
* If the rxbuf is empty and we are not throttled, put as much
* as we can directly into the linux TTY buffer.
*
*/
flip_len = TTY_FLIPBUF_SIZE;
len = min(data_len, flip_len);
len = min(len, (N_TTY_BUF_SIZE - 1) - tp->read_cnt);
ld = tty_ldisc_ref(tp);
/*
* If we were unable to get a reference to the ld,
* don't flush our buffer, and act like the ld doesn't
* have any space to put the data right now.
*/
if (!ld) {
len = 0;
} else {
/*
* If ld doesn't have a pointer to a receive_buf function,
* flush the data, then act like the ld doesn't have any
* space to put the data right now.
*/
if (!ld->receive_buf) {
ch->ch_r_head = ch->ch_r_tail;
len = 0;
}
}
if (len <= 0) {
spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "jsm_input 1\n");
if (ld)
tty_ldisc_deref(ld);
return;
}
len = tty_buffer_request_room(tp, len);
n = len;
/*
* n now contains the most amount of data we can copy,
* bounded either by the flip buffer size or the amount
* of data the card actually has pending...
*/
while (n) {
s = ((head >= tail) ? head : RQUEUESIZE) - tail;
s = min(s, n);
if (s <= 0)
break;
/*
* If conditions are such that ld needs to see all
* UART errors, we will have to walk each character
* and error byte and send them to the buffer one at
* a time.
*/
if (I_PARMRK(tp) || I_BRKINT(tp) || I_INPCK(tp)) {
for (i = 0; i < s; i++) {
/*
* Give the Linux ld the flags in the
* format it likes.
*/
if (*(ch->ch_equeue +tail +i) & UART_LSR_BI)
tty_insert_flip_char(tp, *(ch->ch_rqueue +tail +i), TTY_BREAK);
else if (*(ch->ch_equeue +tail +i) & UART_LSR_PE)
tty_insert_flip_char(tp, *(ch->ch_rqueue +tail +i), TTY_PARITY);
else if (*(ch->ch_equeue +tail +i) & UART_LSR_FE)
tty_insert_flip_char(tp, *(ch->ch_rqueue +tail +i), TTY_FRAME);
else
tty_insert_flip_char(tp, *(ch->ch_rqueue +tail +i), TTY_NORMAL);
}
} else {
tty_insert_flip_string(tp, ch->ch_rqueue + tail, s) ;
}
tail += s;
n -= s;
/* Flip queue if needed */
tail &= rmask;
}
ch->ch_r_tail = tail & rmask;
ch->ch_e_tail = tail & rmask;
jsm_check_queue_flow_control(ch);
spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
/* Tell the tty layer its okay to "eat" the data now */
tty_flip_buffer_push(tp);
if (ld)
tty_ldisc_deref(ld);
jsm_printk(IOCTL, INFO, &ch->ch_bd->pci_dev, "finish\n");
}
static void flush_to_ldisc(struct work_struct *work)
{
struct tty_struct *tty =
container_of(work, struct tty_struct, buf.work);
unsigned long flags;
struct tty_ldisc *disc;
disc = tty_ldisc_ref(tty);
if (disc == NULL) /* !TTY_LDISC */
return;
spin_lock_irqsave(&tty->buf.lock, flags);
if (!test_and_set_bit(TTY_FLUSHING, &tty->flags)) {
struct tty_buffer *head;
while ((head = tty->buf.head) != NULL) {
int count;
char *char_buf;
unsigned char *flag_buf;
unsigned int left = 0;
unsigned int max_space;
count = head->commit - head->read;
if (!count) {
if (head->next == NULL)
break;
tty->buf.head = head->next;
tty_buffer_free(tty, head);
continue;
}
/* Ldisc or user is trying to flush the buffers
we are feeding to the ldisc, stop feeding the
line discipline as we want to empty the queue */
if (test_bit(TTY_FLUSHPENDING, &tty->flags))
break;
/* update receive room */
spin_lock(&tty->read_lock);
if (tty->update_room_in_ldisc) {
if ((tty->read_cnt == N_TTY_BUF_SIZE - 1) &&
(tty->receive_room ==
N_TTY_BUF_SIZE - 1))
tty->rr_bug++;
left = N_TTY_BUF_SIZE - tty->read_cnt - 1;
}
spin_unlock(&tty->read_lock);
if (!tty->receive_room)
break;
if (tty->update_room_in_ldisc && !left) {
schedule_work(&tty->buf.work);
break;
}
if (tty->update_room_in_ldisc)
max_space = min(left, tty->receive_room);
else
max_space = tty->receive_room;
if (count > max_space)
count = max_space;
char_buf = head->char_buf_ptr + head->read;
flag_buf = head->flag_buf_ptr + head->read;
head->read += count;
spin_unlock_irqrestore(&tty->buf.lock, flags);
if(tty->start_debug){
dbg_log_event(NULL, "f_t_l_d:head->read",head->read, "head->commit", head->commit,
"receive_room ", tty->receive_room );
}
tty->ldisc_cnt += count;
disc->ops->receive_buf(tty, char_buf,
flag_buf, count);
spin_lock_irqsave(&tty->buf.lock, flags);
}
clear_bit(TTY_FLUSHING, &tty->flags);
}
/* We may have a deferred request to flush the input buffer,
if so pull the chain under the lock and empty the queue */
if (test_bit(TTY_FLUSHPENDING, &tty->flags)) {
__tty_buffer_flush(tty);
clear_bit(TTY_FLUSHPENDING, &tty->flags);
wake_up(&tty->read_wait);
}
spin_unlock_irqrestore(&tty->buf.lock, flags);
tty_ldisc_deref(disc);
}
