*
* 2002/03/18 Implemented n_tty_wakeup to send SIGIO POLL_OUTs to
* waiting writing processes-Sapan Bhatia <sapan@corewars.org>.
- * Also fixed a bug in BLOCKING mode where write_chan returns
+ * Also fixed a bug in BLOCKING mode where n_tty_write returns
* EAGAIN
*/
static void n_tty_set_room(struct tty_struct *tty)
{
+ /* tty->read_cnt is not read locked ? */
int left = N_TTY_BUF_SIZE - tty->read_cnt - 1;
/*
}
}
+/**
+ * put_tty_queue - add character to tty
+ * @c: character
+ * @tty: tty device
+ *
+ * Add a character to the tty read_buf queue. This is done under the
+ * read_lock to serialize character addition and also to protect us
+ * against parallel reads or flushes
+ */
+
static void put_tty_queue(unsigned char c, struct tty_struct *tty)
{
unsigned long flags;
* check_unthrottle - allow new receive data
* @tty; tty device
*
- * Check whether to call the driver.unthrottle function.
- * We test the TTY_THROTTLED bit first so that it always
- * indicates the current state. The decision about whether
- * it is worth allowing more input has been taken by the caller.
+ * Check whether to call the driver unthrottle functions
+ *
* Can sleep, may be called under the atomic_read_lock mutex but
* this is not guaranteed.
*/
-
static void check_unthrottle(struct tty_struct *tty)
{
if (tty->count)
* Reset the read buffer counters, clear the flags,
* and make sure the driver is unthrottled. Called
* from n_tty_open() and n_tty_flush_buffer().
+ *
+ * Locking: tty_read_lock for read fields.
*/
static void reset_buffer_flags(struct tty_struct *tty)
{
* at hangup) or when the N_TTY line discipline internally has to
* clean the pending queue (for example some signals).
*
- * Locking: ctrl_lock
+ * Locking: ctrl_lock, read_lock.
*/
static void n_tty_flush_buffer(struct tty_struct *tty)
*
* Report the number of characters buffered to be delivered to user
* at this instant in time.
+ *
+ * Locking: read_lock
*/
static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty)
* the simple cases normally found and helps to generate blocks of
* symbols for the console driver and thus improve performance.
*
- * Called from write_chan under the tty layer write lock. Relies
+ * Called from n_tty_write under the tty layer write lock. Relies
* on lock_kernel for the tty->column state.
*/
*
* Echo user input back onto the screen. This must be called only when
* L_ECHO(tty) is true. Called from the driver receive_buf path.
+ *
+ * Relies on BKL for tty column locking
*/
static void echo_char(unsigned char c, struct tty_struct *tty)
opost(c, tty);
}
+/**
+ * finsh_erasing - complete erase
+ * @tty: tty doing the erase
+ *
+ * Relies on BKL for tty column locking
+ */
static inline void finish_erasing(struct tty_struct *tty)
{
if (tty->erasing) {
* Perform erase and necessary output when an erase character is
* present in the stream from the driver layer. Handles the complexities
* of UTF-8 multibyte symbols.
+ *
+ * Locking: read_lock for tty buffers, BKL for column/erasing state
*/
static void eraser(unsigned char c, struct tty_struct *tty)
int head, seen_alnums, cnt;
unsigned long flags;
+ /* FIXME: locking needed ? */
if (tty->read_head == tty->canon_head) {
/* opost('\a', tty); */ /* what do you think? */
return;
}
seen_alnums = 0;
+ /* FIXME: Locking ?? */
while (tty->read_head != tty->canon_head) {
head = tty->read_head;
* may caus terminal flushing to take place according to the termios
* settings and character used. Called from the driver receive_buf
* path so serialized.
+ *
+ * Locking: ctrl_lock, read_lock (both via flush buffer)
*/
static inline void isig(int sig, struct tty_struct *tty, int flush)
* and is protected from re-entry by the tty layer. The user is
* guaranteed that this function will not be re-entered or in progress
* when the ldisc is closed.
+ *
+ * Locking: Caller holds tty->termios_mutex
*/
static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
{
- if (!tty)
- return;
+ int canon_change = 1;
+ BUG_ON(!tty);
+
+ if (old)
+ canon_change = (old->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)
+ wake_up_interruptible(&tty->read_wait);
tty->icanon = (L_ICANON(tty) != 0);
if (test_bit(TTY_HW_COOK_IN, &tty->flags)) {
* @b: user data
* @nr: size of data
*
- * Helper function to speed up read_chan. It is only called when
+ * Helper function to speed up n_tty_read. It is only called when
* ICANON is off; it copies characters straight from the tty queue to
* user space directly. It can be profitably called twice; once to
* drain the space from the tail pointer to the (physical) end of the
if (file->f_op->write != redirected_tty_write &&
current->signal->tty == tty) {
if (!tty->pgrp)
- printk(KERN_ERR "read_chan: no tty->pgrp!\n");
+ printk(KERN_ERR "n_tty_read: no tty->pgrp!\n");
else if (task_pgrp(current) != tty->pgrp) {
if (is_ignored(SIGTTIN) ||
is_current_pgrp_orphaned())
/**
- * read_chan - read function for tty
+ * n_tty_read - read function for tty
* @tty: tty device
* @file: file object
* @buf: userspace buffer pointer
* This code must be sure never to sleep through a hangup.
*/
-static ssize_t read_chan(struct tty_struct *tty, struct file *file,
+static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
unsigned char __user *buf, size_t nr)
{
unsigned char __user *b = buf;
do_it_again:
- if (!tty->read_buf) {
- printk(KERN_ERR "n_tty_read_chan: read_buf == NULL?!?\n");
- return -EIO;
- }
+ BUG_ON(!tty->read_buf);
c = job_control(tty, file);
if (c < 0)
}
/**
- * write_chan - write function for tty
+ * n_tty_write - write function for tty
* @tty: tty device
* @file: file object
* @buf: userspace buffer pointer
* This code must be sure never to sleep through a hangup.
*/
-static ssize_t write_chan(struct tty_struct *tty, struct file *file,
+static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
const unsigned char *buf, size_t nr)
{
const unsigned char *b = buf;
}
/**
- * normal_poll - poll method for N_TTY
+ * n_tty_poll - poll method for N_TTY
* @tty: terminal device
* @file: file accessing it
* @wait: poll table
* Called without the kernel lock held - fine
*/
-static unsigned int normal_poll(struct tty_struct *tty, struct file *file,
+static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file,
poll_table *wait)
{
unsigned int mask = 0;
return mask;
}
+static unsigned long inq_canon(struct tty_struct *tty)
+{
+ int nr, head, tail;
+
+ if (!tty->canon_data)
+ return 0;
+ head = tty->canon_head;
+ tail = tty->read_tail;
+ nr = (head - tail) & (N_TTY_BUF_SIZE-1);
+ /* Skip EOF-chars.. */
+ while (head != tail) {
+ if (test_bit(tail, tty->read_flags) &&
+ tty->read_buf[tail] == __DISABLED_CHAR)
+ nr--;
+ tail = (tail+1) & (N_TTY_BUF_SIZE-1);
+ }
+ return nr;
+}
+
+static int n_tty_ioctl(struct tty_struct *tty, struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ int retval;
+
+ switch (cmd) {
+ case TIOCOUTQ:
+ return put_user(tty_chars_in_buffer(tty), (int __user *) arg);
+ case TIOCINQ:
+ /* FIXME: Locking */
+ retval = tty->read_cnt;
+ if (L_ICANON(tty))
+ retval = inq_canon(tty);
+ return put_user(retval, (unsigned int __user *) arg);
+ default:
+ return n_tty_ioctl_helper(tty, file, cmd, arg);
+ }
+}
+
struct tty_ldisc_ops tty_ldisc_N_TTY = {
.magic = TTY_LDISC_MAGIC,
.name = "n_tty",
.close = n_tty_close,
.flush_buffer = n_tty_flush_buffer,
.chars_in_buffer = n_tty_chars_in_buffer,
- .read = read_chan,
- .write = write_chan,
+ .read = n_tty_read,
+ .write = n_tty_write,
.ioctl = n_tty_ioctl,
.set_termios = n_tty_set_termios,
- .poll = normal_poll,
+ .poll = n_tty_poll,
.receive_buf = n_tty_receive_buf,
.write_wakeup = n_tty_write_wakeup
};
projects / linux-2.6-omap-h63xx.git / blobdiff