}
/**
- * tty_buffer_flush - flush full tty buffers
+ * __tty_buffer_flush - flush full tty buffers
* @tty: tty to flush
*
- * flush all the buffers containing receive data
+ * flush all the buffers containing receive data. Caller must
+ * hold the buffer lock and must have ensured no parallel flush to
+ * ldisc is running.
*
- * Locking: none
+ * Locking: Caller must hold tty->buf.lock
*/
-static void tty_buffer_flush(struct tty_struct *tty)
+static void __tty_buffer_flush(struct tty_struct *tty)
{
struct tty_buffer *thead;
- unsigned long flags;
- spin_lock_irqsave(&tty->buf.lock, flags);
while((thead = tty->buf.head) != NULL) {
tty->buf.head = thead->next;
tty_buffer_free(tty, thead);
}
tty->buf.tail = NULL;
+}
+
+/**
+ * tty_buffer_flush - flush full tty buffers
+ * @tty: tty to flush
+ *
+ * flush all the buffers containing receive data. If the buffer is
+ * being processed by flush_to_ldisc then we defer the processing
+ * to that function
+ *
+ * Locking: none
+ */
+
+static void tty_buffer_flush(struct tty_struct *tty)
+{
+ unsigned long flags;
+ spin_lock_irqsave(&tty->buf.lock, flags);
+
+ /* If the data is being pushed to the tty layer then we can't
+ process it here. Instead set a flag and the flush_to_ldisc
+ path will process the flush request before it exits */
+ if (test_bit(TTY_FLUSHING, &tty->flags)) {
+ set_bit(TTY_FLUSHPENDING, &tty->flags);
+ spin_unlock_irqrestore(&tty->buf.lock, flags);
+ wait_event(tty->read_wait,
+ test_bit(TTY_FLUSHPENDING, &tty->flags) == 0);
+ return;
+ } else
+ __tty_buffer_flush(tty);
spin_unlock_irqrestore(&tty->buf.lock, flags);
}
return 0;
if (is_current_pgrp_orphaned())
return -EIO;
- (void) kill_pgrp(task_pgrp(current), SIGTTOU, 1);
+ kill_pgrp(task_pgrp(current), SIGTTOU, 1);
+ set_thread_flag(TIF_SIGPENDING);
return -ERESTARTSYS;
}
return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
}
-static long hung_up_tty_ioctl(struct file * file,
- unsigned int cmd, unsigned long arg)
+static int hung_up_tty_ioctl(struct inode * inode, struct file * file,
+ unsigned int cmd, unsigned long arg)
+{
+ return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
+}
+
+static long hung_up_tty_compat_ioctl(struct file * file,
+ unsigned int cmd, unsigned long arg)
{
return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
}
.read = hung_up_tty_read,
.write = hung_up_tty_write,
.poll = hung_up_tty_poll,
- .unlocked_ioctl = hung_up_tty_ioctl,
- .compat_ioctl = hung_up_tty_ioctl,
+ .ioctl = hung_up_tty_ioctl,
+ .compat_ioctl = hung_up_tty_compat_ioctl,
.release = tty_release,
};
EXPORT_SYMBOL(tty_hung_up_p);
+/**
+ * is_tty - checker whether file is a TTY
+ */
+int is_tty(struct file *filp)
+{
+ return filp->f_op->read == tty_read
+ || filp->f_op->read == hung_up_tty_read;
+}
+
static void session_clear_tty(struct pid *session)
{
struct task_struct *p;
return i;
}
+void tty_write_unlock(struct tty_struct *tty)
+{
+ mutex_unlock(&tty->atomic_write_lock);
+ wake_up_interruptible(&tty->write_wait);
+}
+
+int tty_write_lock(struct tty_struct *tty, int ndelay)
+{
+ if (!mutex_trylock(&tty->atomic_write_lock)) {
+ if (ndelay)
+ return -EAGAIN;
+ if (mutex_lock_interruptible(&tty->atomic_write_lock))
+ return -ERESTARTSYS;
+ }
+ return 0;
+}
+
/*
* Split writes up in sane blocksizes to avoid
* denial-of-service type attacks
const char __user *buf,
size_t count)
{
- ssize_t ret = 0, written = 0;
+ ssize_t ret, written = 0;
unsigned int chunk;
- /* FIXME: O_NDELAY ... */
- if (mutex_lock_interruptible(&tty->atomic_write_lock)) {
- return -ERESTARTSYS;
- }
+ ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
+ if (ret < 0)
+ return ret;
/*
* We chunk up writes into a temporary buffer. This
buf = kmalloc(chunk, GFP_KERNEL);
if (!buf) {
- mutex_unlock(&tty->atomic_write_lock);
- return -ENOMEM;
+ ret = -ENOMEM;
+ goto out;
}
kfree(tty->write_buf);
tty->write_cnt = chunk;
inode->i_mtime = current_fs_time(inode->i_sb);
ret = written;
}
- mutex_unlock(&tty->atomic_write_lock);
+out:
+ tty_write_unlock(tty);
return ret;
}
}
if (!*tp_loc) {
- tp = (struct ktermios *) kmalloc(sizeof(struct ktermios),
- GFP_KERNEL);
+ tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
if (!tp)
goto free_mem_out;
*tp = driver->init_termios;
}
if (!*ltp_loc) {
- ltp = (struct ktermios *) kmalloc(sizeof(struct ktermios),
- GFP_KERNEL);
+ ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL);
if (!ltp)
goto free_mem_out;
- memset(ltp, 0, sizeof(struct ktermios));
}
if (driver->type == TTY_DRIVER_TYPE_PTY) {
}
if (!*o_tp_loc) {
- o_tp = (struct ktermios *)
- kmalloc(sizeof(struct ktermios), GFP_KERNEL);
+ o_tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
if (!o_tp)
goto free_mem_out;
*o_tp = driver->other->init_termios;
}
if (!*o_ltp_loc) {
- o_ltp = (struct ktermios *)
- kmalloc(sizeof(struct ktermios), GFP_KERNEL);
+ o_ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL);
if (!o_ltp)
goto free_mem_out;
- memset(o_ltp, 0, sizeof(struct ktermios));
}
/*
__proc_set_tty(current, tty);
spin_unlock_irq(¤t->sighand->siglock);
mutex_unlock(&tty_mutex);
+ tty_audit_opening();
return 0;
}
check_tty_count(tty, "tty_open");
retval = ptm_driver->open(tty, filp);
- if (!retval)
+ if (!retval) {
+ tty_audit_opening();
return 0;
+ }
out1:
release_dev(filp);
return retval;
static int send_break(struct tty_struct *tty, unsigned int duration)
{
- if (mutex_lock_interruptible(&tty->atomic_write_lock))
+ if (tty_write_lock(tty, 0) < 0)
return -EINTR;
tty->driver->break_ctl(tty, -1);
- if (!signal_pending(current)) {
+ if (!signal_pending(current))
msleep_interruptible(duration);
- }
tty->driver->break_ctl(tty, 0);
- mutex_unlock(&tty->atomic_write_lock);
+ tty_write_unlock(tty);
if (signal_pending(current))
return -EINTR;
return 0;
return;
spin_lock_irqsave(&tty->buf.lock, flags);
+ set_bit(TTY_FLUSHING, &tty->flags); /* So we know a flush is running */
head = tty->buf.head;
if (head != NULL) {
tty->buf.head = NULL;
tty_buffer_free(tty, tbuf);
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) {
schedule_delayed_work(&tty->buf.work, 1);
break;
disc->receive_buf(tty, char_buf, flag_buf, count);
spin_lock_irqsave(&tty->buf.lock, flags);
}
+ /* Restore the queue head */
tty->buf.head = head;
}
+ /* 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);
+ }
+ clear_bit(TTY_FLUSHING, &tty->flags);
spin_unlock_irqrestore(&tty->buf.lock, flags);
tty_ldisc_deref(disc);
{
struct tty_driver *driver;
- driver = kmalloc(sizeof(struct tty_driver), GFP_KERNEL);
+ driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
if (driver) {
- memset(driver, 0, sizeof(struct tty_driver));
driver->magic = TTY_DRIVER_MAGIC;
driver->num = lines;
/* later we'll move allocation of tables here */
projects / cascardo / linux.git / blobdiff