spin_unlock_irqrestore(&tty->read_lock, flags);
}
-/*
- * Check whether to call the driver.unthrottle function.
- * We test the TTY_THROTTLED bit first so that it always
- * indicates the current state.
+/**
+ * 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.
+ * Can sleep, may be called under the atomic_read semaphore but
+ * this is not guaranteed.
*/
+
static void check_unthrottle(struct tty_struct * tty)
{
if (tty->count &&
tty->driver->unthrottle(tty);
}
-/*
- * 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().
+/**
+ * reset_buffer_flags - reset buffer state
+ * @tty: terminal to reset
+ *
+ * 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().
*/
static void reset_buffer_flags(struct tty_struct *tty)
{
check_unthrottle(tty);
}
-/*
- * Flush the input buffer
+/**
+ * n_tty_flush_buffer - clean input queue
+ * @tty: terminal device
+ *
+ * Flush the input buffer. Called when the line discipline is
+ * being closed, when the tty layer wants the buffer flushed (eg
+ * at hangup) or when the N_TTY line discipline internally has to
+ * clean the pending queue (for example some signals).
+ *
+ * FIXME: tty->ctrl_status is not spinlocked and relies on
+ * lock_kernel() still.
*/
+
void n_tty_flush_buffer(struct tty_struct * tty)
{
/* clear everything and unthrottle the driver */
}
}
-/*
- * Return number of characters buffered to be delivered to user
+/**
+ * n_tty_chars_in_buffer - report available bytes
+ * @tty: tty device
+ *
+ * Report the number of characters buffered to be delivered to user
+ * at this instant in time.
*/
+
ssize_t n_tty_chars_in_buffer(struct tty_struct *tty)
{
unsigned long flags;
return n;
}
+/**
+ * is_utf8_continuation - utf8 multibyte check
+ * @c: byte to check
+ *
+ * Returns true if the utf8 character 'c' is a multibyte continuation
+ * character. We use this to correctly compute the on screen size
+ * of the character when printing
+ */
+
static inline int is_utf8_continuation(unsigned char c)
{
return (c & 0xc0) == 0x80;
}
+/**
+ * is_continuation - multibyte check
+ * @c: byte to check
+ *
+ * Returns true if the utf8 character 'c' is a multibyte continuation
+ * character and the terminal is in unicode mode.
+ */
+
static inline int is_continuation(unsigned char c, struct tty_struct *tty)
{
return I_IUTF8(tty) && is_utf8_continuation(c);
}
-/*
- * Perform OPOST processing. Returns -1 when the output device is
- * full and the character must be retried.
+/**
+ * opost - output post processor
+ * @c: character (or partial unicode symbol)
+ * @tty: terminal device
+ *
+ * Perform OPOST processing. Returns -1 when the output device is
+ * full and the character must be retried. Note that Linux currently
+ * ignores TABDLY, CRDLY, VTDLY, FFDLY and NLDLY. They simply aren't
+ * relevant in the world today. If you ever need them, add them here.
+ *
+ * Called from both the receive and transmit sides and can be called
+ * re-entrantly. Relies on lock_kernel() still.
*/
+
static int opost(unsigned char c, struct tty_struct *tty)
{
int space, spaces;
return 0;
}
-/*
- * opost_block --- to speed up block console writes, among other
- * things.
+/**
+ * opost_block - block postprocess
+ * @tty: terminal device
+ * @inbuf: user buffer
+ * @nr: number of bytes
+ *
+ * This path is used to speed up block console writes, among other
+ * things when processing blocks of output data. It handles only
+ * 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.
*/
+
static ssize_t opost_block(struct tty_struct * tty,
const unsigned char __user * inbuf, unsigned int nr)
{
}
-
+/**
+ * put_char - write character to driver
+ * @c: character (or part of unicode symbol)
+ * @tty: terminal device
+ *
+ * Queue a byte to the driver layer for output
+ */
+
static inline void put_char(unsigned char c, struct tty_struct *tty)
{
tty->driver->put_char(tty, c);
}
-/* Must be called only when L_ECHO(tty) is true. */
+/**
+ * echo_char - echo characters
+ * @c: unicode byte to echo
+ * @tty: terminal device
+ *
+ * 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.
+ */
static void echo_char(unsigned char c, struct tty_struct *tty)
{
}
}
+/**
+ * eraser - handle erase function
+ * @c: character input
+ * @tty: terminal device
+ *
+ * Perform erase and neccessary output when an erase character is
+ * present in the stream from the driver layer. Handles the complexities
+ * of UTF-8 multibyte symbols.
+ */
+
static void eraser(unsigned char c, struct tty_struct *tty)
{
enum { ERASE, WERASE, KILL } kill_type;
finish_erasing(tty);
}
+/**
+ * isig - handle the ISIG optio
+ * @sig: signal
+ * @tty: terminal
+ * @flush: force flush
+ *
+ * Called when a signal is being sent due to terminal input. This
+ * may caus terminal flushing to take place according to the termios
+ * settings and character used. Called from the driver receive_buf
+ * path so serialized.
+ */
+
static inline void isig(int sig, struct tty_struct *tty, int flush)
{
if (tty->pgrp > 0)
}
}
+/**
+ * n_tty_receive_break - handle break
+ * @tty: terminal
+ *
+ * An RS232 break event has been hit in the incoming bitstream. This
+ * can cause a variety of events depending upon the termios settings.
+ *
+ * Called from the receive_buf path so single threaded.
+ */
+
static inline void n_tty_receive_break(struct tty_struct *tty)
{
if (I_IGNBRK(tty))
wake_up_interruptible(&tty->read_wait);
}
+/**
+ * n_tty_receive_overrun - handle overrun reporting
+ * @tty: terminal
+ *
+ * Data arrived faster than we could process it. While the tty
+ * driver has flagged this the bits that were missed are gone
+ * forever.
+ *
+ * Called from the receive_buf path so single threaded. Does not
+ * need locking as num_overrun and overrun_time are function
+ * private.
+ */
+
static inline void n_tty_receive_overrun(struct tty_struct *tty)
{
char buf[64];
tty->num_overrun++;
if (time_before(tty->overrun_time, jiffies - HZ)) {
- printk("%s: %d input overrun(s)\n", tty_name(tty, buf),
+ printk(KERN_WARNING "%s: %d input overrun(s)\n", tty_name(tty, buf),
tty->num_overrun);
tty->overrun_time = jiffies;
tty->num_overrun = 0;
}
}
+/**
+ * n_tty_receive_parity_error - error notifier
+ * @tty: terminal device
+ * @c: character
+ *
+ * Process a parity error and queue the right data to indicate
+ * the error case if neccessary. Locking as per n_tty_receive_buf.
+ */
static inline void n_tty_receive_parity_error(struct tty_struct *tty,
unsigned char c)
{
wake_up_interruptible(&tty->read_wait);
}
+/**
+ * n_tty_receive_char - perform processing
+ * @tty: terminal device
+ * @c: character
+ *
+ * Process an individual character of input received from the driver.
+ * This is serialized with respect to itself by the rules for the
+ * driver above.
+ */
+
static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
{
unsigned long flags;
put_tty_queue(c, tty);
}
+/**
+ * n_tty_receive_room - receive space
+ * @tty: terminal
+ *
+ * Called by the driver to find out how much data it is
+ * permitted to feed to the line discipline without any being lost
+ * and thus to manage flow control. Not serialized. Answers for the
+ * "instant".
+ */
+
static int n_tty_receive_room(struct tty_struct *tty)
{
int left = N_TTY_BUF_SIZE - tty->read_cnt - 1;
return 0;
}
-/*
- * Required for the ptys, serial driver etc. since processes
- * that attach themselves to the master and rely on ASYNC
- * IO must be woken up
+/**
+ * n_tty_write_wakeup - asynchronous I/O notifier
+ * @tty: tty device
+ *
+ * Required for the ptys, serial driver etc. since processes
+ * that attach themselves to the master and rely on ASYNC
+ * IO must be woken up
*/
static void n_tty_write_wakeup(struct tty_struct *tty)
return;
}
+/**
+ * n_tty_receive_buf - data receive
+ * @tty: terminal device
+ * @cp: buffer
+ * @fp: flag buffer
+ * @count: characters
+ *
+ * Called by the terminal driver when a block of characters has
+ * been received. This function must be called from soft contexts
+ * not from interrupt context. The driver is responsible for making
+ * calls one at a time and in order (or using flush_to_ldisc)
+ */
+
static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
char *fp, int count)
{
current->sighand->action[sig-1].sa.sa_handler == SIG_IGN);
}
+/**
+ * n_tty_set_termios - termios data changed
+ * @tty: terminal
+ * @old: previous data
+ *
+ * Called by the tty layer when the user changes termios flags so
+ * that the line discipline can plan ahead. This function cannot sleep
+ * 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.
+ */
+
static void n_tty_set_termios(struct tty_struct *tty, struct termios * old)
{
if (!tty)
I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) ||
I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) ||
I_PARMRK(tty)) {
- local_irq_disable(); // FIXME: is this safe?
memset(tty->process_char_map, 0, 256/8);
if (I_IGNCR(tty) || I_ICRNL(tty))
set_bit(SUSP_CHAR(tty), tty->process_char_map);
}
clear_bit(__DISABLED_CHAR, tty->process_char_map);
- local_irq_enable(); // FIXME: is this safe?
tty->raw = 0;
tty->real_raw = 0;
} else {
}
}
+/**
+ * n_tty_close - close the ldisc for this tty
+ * @tty: device
+ *
+ * Called from the terminal layer when this line discipline is
+ * being shut down, either because of a close or becsuse of a
+ * discipline change. The function will not be called while other
+ * ldisc methods are in progress.
+ */
+
static void n_tty_close(struct tty_struct *tty)
{
n_tty_flush_buffer(tty);
}
}
+/**
+ * n_tty_open - open an ldisc
+ * @tty: terminal to open
+ *
+ * Called when this line discipline is being attached to the
+ * terminal device. Can sleep. Called serialized so that no
+ * other events will occur in parallel. No further open will occur
+ * until a close.
+ */
+
static int n_tty_open(struct tty_struct *tty)
{
if (!tty)
return -EINVAL;
+ /* This one is ugly. Currently a malloc failure here can panic */
if (!tty->read_buf) {
tty->read_buf = alloc_buf();
if (!tty->read_buf)
return 0;
}
-/*
- * Helper function to speed up read_chan. 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
- * buffer, and once to drain the space from the (physical) beginning of
- * the buffer to head pointer.
+/**
+ * copy_from_read_buf - copy read data directly
+ * @tty: terminal device
+ * @b: user data
+ * @nr: size of data
+ *
+ * Helper function to speed up read_chan. 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
+ * buffer, and once to drain the space from the (physical) beginning of
+ * the buffer to head pointer.
+ *
+ * Called under the tty->atomic_read sem and with TTY_DONT_FLIP set
+ *
*/
+
static inline int copy_from_read_buf(struct tty_struct *tty,
unsigned char __user **b,
size_t *nr)
extern ssize_t redirected_tty_write(struct file *,const char *,size_t,loff_t *);
-static ssize_t read_chan(struct tty_struct *tty, struct file *file,
- unsigned char __user *buf, size_t nr)
+/**
+ * job_control - check job control
+ * @tty: tty
+ * @file: file handle
+ *
+ * Perform job control management checks on this file/tty descriptor
+ * and if appropriate send any needed signals and return a negative
+ * error code if action should be taken.
+ */
+
+static int job_control(struct tty_struct *tty, struct file *file)
{
- unsigned char __user *b = buf;
- DECLARE_WAITQUEUE(wait, current);
- int c;
- int minimum, time;
- ssize_t retval = 0;
- ssize_t size;
- long timeout;
- unsigned long flags;
-
-do_it_again:
-
- if (!tty->read_buf) {
- printk("n_tty_read_chan: called with read_buf == NULL?!?\n");
- return -EIO;
- }
-
/* Job control check -- must be done at start and after
every sleep (POSIX.1 7.1.1.4). */
/* NOTE: not yet done after every sleep pending a thorough
return -ERESTARTSYS;
}
}
+ return 0;
+}
+
+
+/**
+ * read_chan - read function for tty
+ * @tty: tty device
+ * @file: file object
+ * @buf: userspace buffer pointer
+ * @nr: size of I/O
+ *
+ * Perform reads for the line discipline. We are guaranteed that the
+ * line discipline will not be closed under us but we may get multiple
+ * parallel readers and must handle this ourselves. We may also get
+ * a hangup. Always called in user context, may sleep.
+ *
+ * This code must be sure never to sleep through a hangup.
+ */
+
+static ssize_t read_chan(struct tty_struct *tty, struct file *file,
+ unsigned char __user *buf, size_t nr)
+{
+ unsigned char __user *b = buf;
+ DECLARE_WAITQUEUE(wait, current);
+ int c;
+ int minimum, time;
+ ssize_t retval = 0;
+ ssize_t size;
+ long timeout;
+ unsigned long flags;
+
+do_it_again:
+
+ if (!tty->read_buf) {
+ printk("n_tty_read_chan: called with read_buf == NULL?!?\n");
+ return -EIO;
+ }
+ c = job_control(tty, file);
+ if(c < 0)
+ return c;
+
minimum = time = 0;
timeout = MAX_SCHEDULE_TIMEOUT;
if (!tty->icanon) {
}
}
+ /*
+ * Internal serialization of reads.
+ */
if (file->f_flags & O_NONBLOCK) {
if (down_trylock(&tty->atomic_read))
return -EAGAIN;
return retval;
}
+/**
+ * write_chan - write function for tty
+ * @tty: tty device
+ * @file: file object
+ * @buf: userspace buffer pointer
+ * @nr: size of I/O
+ *
+ * Write function of the terminal device. This is serialized with
+ * respect to other write callers but not to termios changes, reads
+ * and other such events. We must be careful with N_TTY as the receive
+ * code will echo characters, thus calling driver write methods.
+ *
+ * This code must be sure never to sleep through a hangup.
+ */
+
static ssize_t write_chan(struct tty_struct * tty, struct file * file,
const unsigned char __user * buf, size_t nr)
{
return (b - buf) ? b - buf : retval;
}
-/* Called without the kernel lock held - fine */
+/**
+ * normal_poll - poll method for N_TTY
+ * @tty: terminal device
+ * @file: file accessing it
+ * @wait: poll table
+ *
+ * Called when the line discipline is asked to poll() for data or
+ * for special events. This code is not serialized with respect to
+ * other events save open/close.
+ *
+ * This code must be sure never to sleep through a hangup.
+ * Called without the kernel lock held - fine
+ *
+ * FIXME: if someone changes the VMIN or discipline settings for the
+ * terminal while another process is in poll() the poll does not
+ * recompute the new limits. Possibly set_termios should issue
+ * a read wakeup to fix this bug.
+ */
+
static unsigned int normal_poll(struct tty_struct * tty, struct file * file, poll_table *wait)
{
unsigned int mask = 0;
n_tty_ioctl, /* ioctl */
n_tty_set_termios, /* set_termios */
normal_poll, /* poll */
+ NULL, /* hangup */
n_tty_receive_buf, /* receive_buf */
n_tty_receive_room, /* receive_room */
n_tty_write_wakeup /* write_wakeup */
git://git.onelab.eu / linux-2.6.git / blobdiff