diff options
Diffstat (limited to 'drivers/tty/n_tty.c')
| -rw-r--r-- | drivers/tty/n_tty.c | 2053 |
1 files changed, 1227 insertions, 826 deletions
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index 428f4fe0b5f..f44f1ba762c 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -49,8 +49,9 @@ #include <linux/file.h> #include <linux/uaccess.h> #include <linux/module.h> +#include <linux/ratelimit.h> +#include <linux/vmalloc.h> -#include <asm/system.h> /* number of characters left in xmit buffer before select has we have room */ #define WAKEUP_CHARS 256 @@ -61,7 +62,7 @@ * controlling the space in the read buffer. */ #define TTY_THRESHOLD_THROTTLE 128 /* now based on remaining room */ -#define TTY_THRESHOLD_UNTHROTTLE 128 +#define TTY_THRESHOLD_UNTHROTTLE 128 /* * Special byte codes used in the echo buffer to represent operations @@ -74,27 +75,104 @@ #define ECHO_OP_SET_CANON_COL 0x81 #define ECHO_OP_ERASE_TAB 0x82 +#define ECHO_COMMIT_WATERMARK 256 +#define ECHO_BLOCK 256 +#define ECHO_DISCARD_WATERMARK N_TTY_BUF_SIZE - (ECHO_BLOCK + 32) + + +#undef N_TTY_TRACE +#ifdef N_TTY_TRACE +# define n_tty_trace(f, args...) trace_printk(f, ##args) +#else +# define n_tty_trace(f, args...) +#endif + +struct n_tty_data { + /* producer-published */ + size_t read_head; + size_t canon_head; + size_t echo_head; + size_t echo_commit; + size_t echo_mark; + DECLARE_BITMAP(char_map, 256); + + /* private to n_tty_receive_overrun (single-threaded) */ + unsigned long overrun_time; + int num_overrun; + + /* non-atomic */ + bool no_room; + + /* must hold exclusive termios_rwsem to reset these */ + unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1; + unsigned char push:1; + + /* shared by producer and consumer */ + char read_buf[N_TTY_BUF_SIZE]; + DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE); + unsigned char echo_buf[N_TTY_BUF_SIZE]; + + int minimum_to_wake; + + /* consumer-published */ + size_t read_tail; + size_t line_start; + + /* protected by output lock */ + unsigned int column; + unsigned int canon_column; + size_t echo_tail; + + struct mutex atomic_read_lock; + struct mutex output_lock; +}; + +static inline size_t read_cnt(struct n_tty_data *ldata) +{ + return ldata->read_head - ldata->read_tail; +} + +static inline unsigned char read_buf(struct n_tty_data *ldata, size_t i) +{ + return ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; +} + +static inline unsigned char *read_buf_addr(struct n_tty_data *ldata, size_t i) +{ + return &ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)]; +} + +static inline unsigned char echo_buf(struct n_tty_data *ldata, size_t i) +{ + return ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)]; +} + +static inline unsigned char *echo_buf_addr(struct n_tty_data *ldata, size_t i) +{ + return &ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)]; +} + static inline int tty_put_user(struct tty_struct *tty, unsigned char x, unsigned char __user *ptr) { - tty_audit_add_data(tty, &x, 1); + struct n_tty_data *ldata = tty->disc_data; + + tty_audit_add_data(tty, &x, 1, ldata->icanon); return put_user(x, ptr); } -/** - * n_tty_set__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 void n_tty_set_room(struct tty_struct *tty) +static int receive_room(struct tty_struct *tty) { - /* tty->read_cnt is not read locked ? */ - int left = N_TTY_BUF_SIZE - tty->read_cnt - 1; + struct n_tty_data *ldata = tty->disc_data; + int left; + + if (I_PARMRK(tty)) { + /* Multiply read_cnt by 3, since each byte might take up to + * three times as many spaces when PARMRK is set (depending on + * its flags, e.g. parity error). */ + left = N_TTY_BUF_SIZE - read_cnt(ldata) * 3 - 1; + } else + left = N_TTY_BUF_SIZE - read_cnt(ldata) - 1; /* * If we are doing input canonicalization, and there are no @@ -103,112 +181,208 @@ static void n_tty_set_room(struct tty_struct *tty) * characters will be beeped. */ if (left <= 0) - left = tty->icanon && !tty->canon_data; - tty->receive_room = left; + left = ldata->icanon && ldata->canon_head == ldata->read_tail; + + return left; } -static void put_tty_queue_nolock(unsigned char c, struct tty_struct *tty) +/** + * n_tty_set_room - receive space + * @tty: terminal + * + * Re-schedules the flip buffer work if space just became available. + * + * Caller holds exclusive termios_rwsem + * or + * n_tty_read()/consumer path: + * holds non-exclusive termios_rwsem + */ + +static void n_tty_set_room(struct tty_struct *tty) { - if (tty->read_cnt < N_TTY_BUF_SIZE) { - tty->read_buf[tty->read_head] = c; - tty->read_head = (tty->read_head + 1) & (N_TTY_BUF_SIZE-1); - tty->read_cnt++; + struct n_tty_data *ldata = tty->disc_data; + + /* Did this open up the receive buffer? We may need to flip */ + if (unlikely(ldata->no_room) && receive_room(tty)) { + ldata->no_room = 0; + + WARN_RATELIMIT(tty->port->itty == NULL, + "scheduling with invalid itty\n"); + /* see if ldisc has been killed - if so, this means that + * even though the ldisc has been halted and ->buf.work + * cancelled, ->buf.work is about to be rescheduled + */ + WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags), + "scheduling buffer work for halted ldisc\n"); + queue_work(system_unbound_wq, &tty->port->buf.work); } } +static ssize_t chars_in_buffer(struct tty_struct *tty) +{ + struct n_tty_data *ldata = tty->disc_data; + ssize_t n = 0; + + if (!ldata->icanon) + n = read_cnt(ldata); + else + n = ldata->canon_head - ldata->read_tail; + return n; +} + /** - * put_tty_queue - add character to tty - * @c: character + * n_tty_write_wakeup - asynchronous I/O notifier * @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 + * 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 put_tty_queue(unsigned char c, struct tty_struct *tty) +static void n_tty_write_wakeup(struct tty_struct *tty) { - unsigned long flags; + if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) + kill_fasync(&tty->fasync, SIGIO, POLL_OUT); +} + +static void n_tty_check_throttle(struct tty_struct *tty) +{ + if (tty->driver->type == TTY_DRIVER_TYPE_PTY) + return; /* - * The problem of stomping on the buffers ends here. - * Why didn't anyone see this one coming? --AJK - */ - spin_lock_irqsave(&tty->read_lock, flags); - put_tty_queue_nolock(c, tty); - spin_unlock_irqrestore(&tty->read_lock, flags); + * Check the remaining room for the input canonicalization + * mode. We don't want to throttle the driver if we're in + * canonical mode and don't have a newline yet! + */ + while (1) { + int throttled; + tty_set_flow_change(tty, TTY_THROTTLE_SAFE); + if (receive_room(tty) >= TTY_THRESHOLD_THROTTLE) + break; + throttled = tty_throttle_safe(tty); + if (!throttled) + break; + } + __tty_set_flow_change(tty, 0); +} + +static void n_tty_check_unthrottle(struct tty_struct *tty) +{ + if (tty->driver->type == TTY_DRIVER_TYPE_PTY && + tty->link->ldisc->ops->write_wakeup == n_tty_write_wakeup) { + if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) + return; + if (!tty->count) + return; + n_tty_set_room(tty); + n_tty_write_wakeup(tty->link); + if (waitqueue_active(&tty->link->write_wait)) + wake_up_interruptible_poll(&tty->link->write_wait, POLLOUT); + return; + } + + /* If there is enough space in the read buffer now, let the + * low-level driver know. We use chars_in_buffer() to + * check the buffer, as it now knows about canonical mode. + * Otherwise, if the driver is throttled and the line is + * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, + * we won't get any more characters. + */ + + while (1) { + int unthrottled; + tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); + if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) + break; + if (!tty->count) + break; + n_tty_set_room(tty); + unthrottled = tty_unthrottle_safe(tty); + if (!unthrottled) + break; + } + __tty_set_flow_change(tty, 0); } /** - * check_unthrottle - allow new receive data - * @tty; tty device + * put_tty_queue - add character to tty + * @c: character + * @ldata: n_tty data + * + * Add a character to the tty read_buf queue. * - * Check whether to call the driver unthrottle functions + * n_tty_receive_buf()/producer path: + * caller holds non-exclusive termios_rwsem + * modifies read_head * - * Can sleep, may be called under the atomic_read_lock mutex but - * this is not guaranteed. + * read_head is only considered 'published' if canonical mode is + * not active. */ -static void check_unthrottle(struct tty_struct *tty) + +static inline void put_tty_queue(unsigned char c, struct n_tty_data *ldata) { - if (tty->count) - tty_unthrottle(tty); + *read_buf_addr(ldata, ldata->read_head++) = c; } /** * 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(). + * Reset the read buffer counters and clear the flags. + * Called from n_tty_open() and n_tty_flush_buffer(). * - * Locking: tty_read_lock for read fields. + * Locking: caller holds exclusive termios_rwsem + * (or locking is not required) */ -static void reset_buffer_flags(struct tty_struct *tty) +static void reset_buffer_flags(struct n_tty_data *ldata) { - unsigned long flags; - - spin_lock_irqsave(&tty->read_lock, flags); - tty->read_head = tty->read_tail = tty->read_cnt = 0; - spin_unlock_irqrestore(&tty->read_lock, flags); + ldata->read_head = ldata->canon_head = ldata->read_tail = 0; + ldata->echo_head = ldata->echo_tail = ldata->echo_commit = 0; + ldata->echo_mark = 0; + ldata->line_start = 0; + + ldata->erasing = 0; + bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); + ldata->push = 0; +} - mutex_lock(&tty->echo_lock); - tty->echo_pos = tty->echo_cnt = tty->echo_overrun = 0; - mutex_unlock(&tty->echo_lock); +static void n_tty_packet_mode_flush(struct tty_struct *tty) +{ + unsigned long flags; - tty->canon_head = tty->canon_data = tty->erasing = 0; - memset(&tty->read_flags, 0, sizeof tty->read_flags); - n_tty_set_room(tty); - check_unthrottle(tty); + spin_lock_irqsave(&tty->ctrl_lock, flags); + if (tty->link->packet) { + tty->ctrl_status |= TIOCPKT_FLUSHREAD; + if (waitqueue_active(&tty->link->read_wait)) + wake_up_interruptible(&tty->link->read_wait); + } + spin_unlock_irqrestore(&tty->ctrl_lock, flags); } /** * 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). + * Flush the input buffer. Called 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). * - * Locking: ctrl_lock, read_lock. + * Holds termios_rwsem to exclude producer/consumer while + * buffer indices are reset. + * + * Locking: ctrl_lock, exclusive termios_rwsem */ static void n_tty_flush_buffer(struct tty_struct *tty) { - unsigned long flags; - /* clear everything and unthrottle the driver */ - reset_buffer_flags(tty); - - if (!tty->link) - return; + down_write(&tty->termios_rwsem); + reset_buffer_flags(tty->disc_data); + n_tty_set_room(tty); - spin_lock_irqsave(&tty->ctrl_lock, flags); - if (tty->link->packet) { - tty->ctrl_status |= TIOCPKT_FLUSHREAD; - wake_up_interruptible(&tty->link->read_wait); - } - spin_unlock_irqrestore(&tty->ctrl_lock, flags); + if (tty->link) + n_tty_packet_mode_flush(tty); + up_write(&tty->termios_rwsem); } /** @@ -218,23 +392,18 @@ 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 + * Locking: exclusive termios_rwsem */ static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty) { - unsigned long flags; - ssize_t n = 0; + ssize_t n; - spin_lock_irqsave(&tty->read_lock, flags); - if (!tty->icanon) { - n = tty->read_cnt; - } else if (tty->canon_data) { - n = (tty->canon_head > tty->read_tail) ? - tty->canon_head - tty->read_tail : - tty->canon_head + (N_TTY_BUF_SIZE - tty->read_tail); - } - spin_unlock_irqrestore(&tty->read_lock, flags); + WARN_ONCE(1, "%s is deprecated and scheduled for removal.", __func__); + + down_write(&tty->termios_rwsem); + n = chars_in_buffer(tty); + up_write(&tty->termios_rwsem); return n; } @@ -289,6 +458,7 @@ static inline int is_continuation(unsigned char c, struct tty_struct *tty) static int do_output_char(unsigned char c, struct tty_struct *tty, int space) { + struct n_tty_data *ldata = tty->disc_data; int spaces; if (!space) @@ -297,48 +467,48 @@ static int do_output_char(unsigned char c, struct tty_struct *tty, int space) switch (c) { case '\n': if (O_ONLRET(tty)) - tty->column = 0; + ldata->column = 0; if (O_ONLCR(tty)) { if (space < 2) return -1; - tty->canon_column = tty->column = 0; + ldata->canon_column = ldata->column = 0; tty->ops->write(tty, "\r\n", 2); return 2; } - tty->canon_column = tty->column; + ldata->canon_column = ldata->column; break; case '\r': - if (O_ONOCR(tty) && tty->column == 0) + if (O_ONOCR(tty) && ldata->column == 0) return 0; if (O_OCRNL(tty)) { c = '\n'; if (O_ONLRET(tty)) - tty->canon_column = tty->column = 0; + ldata->canon_column = ldata->column = 0; break; } - tty->canon_column = tty->column = 0; + ldata->canon_column = ldata->column = 0; break; case '\t': - spaces = 8 - (tty->column & 7); + spaces = 8 - (ldata->column & 7); if (O_TABDLY(tty) == XTABS) { if (space < spaces) return -1; - tty->column += spaces; + ldata->column += spaces; tty->ops->write(tty, " ", spaces); return spaces; } - tty->column += spaces; + ldata->column += spaces; break; case '\b': - if (tty->column > 0) - tty->column--; + if (ldata->column > 0) + ldata->column--; break; default: if (!iscntrl(c)) { if (O_OLCUC(tty)) c = toupper(c); if (!is_continuation(c, tty)) - tty->column++; + ldata->column++; } break; } @@ -363,14 +533,15 @@ static int do_output_char(unsigned char c, struct tty_struct *tty, int space) static int process_output(unsigned char c, struct tty_struct *tty) { + struct n_tty_data *ldata = tty->disc_data; int space, retval; - mutex_lock(&tty->output_lock); + mutex_lock(&ldata->output_lock); space = tty_write_room(tty); retval = do_output_char(c, tty, space); - mutex_unlock(&tty->output_lock); + mutex_unlock(&ldata->output_lock); if (retval < 0) return -1; else @@ -399,15 +570,16 @@ static int process_output(unsigned char c, struct tty_struct *tty) static ssize_t process_output_block(struct tty_struct *tty, const unsigned char *buf, unsigned int nr) { + struct n_tty_data *ldata = tty->disc_data; int space; - int i; + int i; const unsigned char *cp; - mutex_lock(&tty->output_lock); + mutex_lock(&ldata->output_lock); space = tty_write_room(tty); if (!space) { - mutex_unlock(&tty->output_lock); + mutex_unlock(&ldata->output_lock); return 0; } if (nr > space) @@ -419,30 +591,30 @@ static ssize_t process_output_block(struct tty_struct *tty, switch (c) { case '\n': if (O_ONLRET(tty)) - tty->column = 0; + ldata->column = 0; if (O_ONLCR(tty)) goto break_out; - tty->canon_column = tty->column; + ldata->canon_column = ldata->column; break; case '\r': - if (O_ONOCR(tty) && tty->column == 0) + if (O_ONOCR(tty) && ldata->column == 0) goto break_out; if (O_OCRNL(tty)) goto break_out; - tty->canon_column = tty->column = 0; + ldata->canon_column = ldata->column = 0; break; case '\t': goto break_out; case '\b': - if (tty->column > 0) - tty->column--; + if (ldata->column > 0) + ldata->column--; break; default: if (!iscntrl(c)) { if (O_OLCUC(tty)) goto break_out; if (!is_continuation(c, tty)) - tty->column++; + ldata->column++; } break; } @@ -450,7 +622,7 @@ static ssize_t process_output_block(struct tty_struct *tty, break_out: i = tty->ops->write(tty, buf, i); - mutex_unlock(&tty->output_lock); + mutex_unlock(&ldata->output_lock); return i; } @@ -476,32 +648,23 @@ break_out: * are prioritized. Also, when control characters are echoed with a * prefixed "^", the pair is treated atomically and thus not separated. * - * Locking: output_lock to protect column state and space left, - * echo_lock to protect the echo buffer + * Locking: callers must hold output_lock */ -static void process_echoes(struct tty_struct *tty) +static size_t __process_echoes(struct tty_struct *tty) { - int space, nr; + struct n_tty_data *ldata = tty->disc_data; + int space, old_space; + size_t tail; unsigned char c; - unsigned char *cp, *buf_end; - if (!tty->echo_cnt) - return; - - mutex_lock(&tty->output_lock); - mutex_lock(&tty->echo_lock); - - space = tty_write_room(tty); + old_space = space = tty_write_room(tty); - buf_end = tty->echo_buf + N_TTY_BUF_SIZE; - cp = tty->echo_buf + tty->echo_pos; - nr = tty->echo_cnt; - while (nr > 0) { - c = *cp; + tail = ldata->echo_tail; + while (ldata->echo_commit != tail) { + c = echo_buf(ldata, tail); if (c == ECHO_OP_START) { unsigned char op; - unsigned char *opp; int no_space_left = 0; /* @@ -509,18 +672,13 @@ static void process_echoes(struct tty_struct *tty) * operation, get the next byte, which is either the * op code or a control character value. */ - opp = cp + 1; - if (opp == buf_end) - opp -= N_TTY_BUF_SIZE; - op = *opp; + op = echo_buf(ldata, tail + 1); switch (op) { unsigned int num_chars, num_bs; case ECHO_OP_ERASE_TAB: - if (++opp == buf_end) - opp -= N_TTY_BUF_SIZE; - num_chars = *opp; + num_chars = echo_buf(ldata, tail + 2); /* * Determine how many columns to go back @@ -533,7 +691,7 @@ static void process_echoes(struct tty_struct *tty) * Otherwise, tab spacing is normal. */ if (!(num_chars & 0x80)) - num_chars += tty->canon_column; + num_chars += ldata->canon_column; num_bs = 8 - (num_chars & 7); if (num_bs > space) { @@ -543,24 +701,21 @@ static void process_echoes(struct tty_struct *tty) space -= num_bs; while (num_bs--) { tty_put_char(tty, '\b'); - if (tty->column > 0) - tty->column--; + if (ldata->column > 0) + ldata->column--; } - cp += 3; - nr -= 3; + tail += 3; break; case ECHO_OP_SET_CANON_COL: - tty->canon_column = tty->column; - cp += 2; - nr -= 2; + ldata->canon_column = ldata->column; + tail += 2; break; case ECHO_OP_MOVE_BACK_COL: - if (tty->column > 0) - tty->column--; - cp += 2; - nr -= 2; + if (ldata->column > 0) + ldata->column--; + tail += 2; break; case ECHO_OP_START: @@ -570,10 +725,9 @@ static void process_echoes(struct tty_struct *tty) break; } tty_put_char(tty, ECHO_OP_START); - tty->column++; + ldata->column++; space--; - cp += 2; - nr -= 2; + tail += 2; break; default: @@ -592,17 +746,15 @@ static void process_echoes(struct tty_struct *tty) } tty_put_char(tty, '^'); tty_put_char(tty, op ^ 0100); - tty->column += 2; + ldata->column += 2; space -= 2; - cp += 2; - nr -= 2; + tail += 2; } if (no_space_left) break; } else { - if (O_OPOST(tty) && - !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) { + if (O_OPOST(tty)) { int retval = do_output_char(c, tty, space); if (retval < 0) break; @@ -613,126 +765,130 @@ static void process_echoes(struct tty_struct *tty) tty_put_char(tty, c); space -= 1; } - cp += 1; - nr -= 1; + tail += 1; } - - /* When end of circular buffer reached, wrap around */ - if (cp >= buf_end) - cp -= N_TTY_BUF_SIZE; } - if (nr == 0) { - tty->echo_pos = 0; - tty->echo_cnt = 0; - tty->echo_overrun = 0; - } else { - int num_processed = tty->echo_cnt - nr; - tty->echo_pos += num_processed; - tty->echo_pos &= N_TTY_BUF_SIZE - 1; - tty->echo_cnt = nr; - if (num_processed > 0) - tty->echo_overrun = 0; + /* If the echo buffer is nearly full (so that the possibility exists + * of echo overrun before the next commit), then discard enough + * data at the tail to prevent a subsequent overrun */ + while (ldata->echo_commit - tail >= ECHO_DISCARD_WATERMARK) { + if (echo_buf(ldata, tail) == ECHO_OP_START) { + if (echo_buf(ldata, tail + 1) == ECHO_OP_ERASE_TAB) + tail += 3; + else + tail += 2; + } else + tail++; } - mutex_unlock(&tty->echo_lock); - mutex_unlock(&tty->output_lock); + ldata->echo_tail = tail; + return old_space - space; +} + +static void commit_echoes(struct tty_struct *tty) +{ + struct n_tty_data *ldata = tty->disc_data; + size_t nr, old, echoed; + size_t head; + + head = ldata->echo_head; + ldata->echo_mark = head; + old = ldata->echo_commit - ldata->echo_tail; + + /* Process committed echoes if the accumulated # of bytes + * is over the threshold (and try again each time another + * block is accumulated) */ + nr = head - ldata->echo_tail; + if (nr < ECHO_COMMIT_WATERMARK || (nr % ECHO_BLOCK > old % ECHO_BLOCK)) + return; + + mutex_lock(&ldata->output_lock); + ldata->echo_commit = head; + echoed = __process_echoes(tty); + mutex_unlock(&ldata->output_lock); + + if (echoed && tty->ops->flush_chars) + tty->ops->flush_chars(tty); +} + +static void process_echoes(struct tty_struct *tty) +{ + struct n_tty_data *ldata = tty->disc_data; + size_t echoed; + + if (ldata->echo_mark == ldata->echo_tail) + return; + + mutex_lock(&ldata->output_lock); + ldata->echo_commit = ldata->echo_mark; + echoed = __process_echoes(tty); + mutex_unlock(&ldata->output_lock); - if (tty->ops->flush_chars) + if (echoed && tty->ops->flush_chars) tty->ops->flush_chars(tty); } +/* NB: echo_mark and echo_head should be equivalent here */ +static void flush_echoes(struct tty_struct *tty) +{ + struct n_tty_data *ldata = tty->disc_data; + + if ((!L_ECHO(tty) && !L_ECHONL(tty)) || + ldata->echo_commit == ldata->echo_head) + return; + + mutex_lock(&ldata->output_lock); + ldata->echo_commit = ldata->echo_head; + __process_echoes(tty); + mutex_unlock(&ldata->output_lock); +} + /** * add_echo_byte - add a byte to the echo buffer * @c: unicode byte to echo - * @tty: terminal device + * @ldata: n_tty data * * Add a character or operation byte to the echo buffer. - * - * Should be called under the echo lock to protect the echo buffer. */ -static void add_echo_byte(unsigned char c, struct tty_struct *tty) +static inline void add_echo_byte(unsigned char c, struct n_tty_data *ldata) { - int new_byte_pos; - - if (tty->echo_cnt == N_TTY_BUF_SIZE) { - /* Circular buffer is already at capacity */ - new_byte_pos = tty->echo_pos; - - /* - * Since the buffer start position needs to be advanced, - * be sure to step by a whole operation byte group. - */ - if (tty->echo_buf[tty->echo_pos] == ECHO_OP_START) { - if (tty->echo_buf[(tty->echo_pos + 1) & - (N_TTY_BUF_SIZE - 1)] == - ECHO_OP_ERASE_TAB) { - tty->echo_pos += 3; - tty->echo_cnt -= 2; - } else { - tty->echo_pos += 2; - tty->echo_cnt -= 1; - } - } else { - tty->echo_pos++; - } - tty->echo_pos &= N_TTY_BUF_SIZE - 1; - - tty->echo_overrun = 1; - } else { - new_byte_pos = tty->echo_pos + tty->echo_cnt; - new_byte_pos &= N_TTY_BUF_SIZE - 1; - tty->echo_cnt++; - } - - tty->echo_buf[new_byte_pos] = c; + *echo_buf_addr(ldata, ldata->echo_head++) = c; } /** * echo_move_back_col - add operation to move back a column - * @tty: terminal device + * @ldata: n_tty data * * Add an operation to the echo buffer to move back one column. - * - * Locking: echo_lock to protect the echo buffer */ -static void echo_move_back_col(struct tty_struct *tty) +static void echo_move_back_col(struct n_tty_data *ldata) { - mutex_lock(&tty->echo_lock); - - add_echo_byte(ECHO_OP_START, tty); - add_echo_byte(ECHO_OP_MOVE_BACK_COL, tty); - - mutex_unlock(&tty->echo_lock); + add_echo_byte(ECHO_OP_START, ldata); + add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata); } /** * echo_set_canon_col - add operation to set the canon column - * @tty: terminal device + * @ldata: n_tty data * * Add an operation to the echo buffer to set the canon column * to the current column. - * - * Locking: echo_lock to protect the echo buffer */ -static void echo_set_canon_col(struct tty_struct *tty) +static void echo_set_canon_col(struct n_tty_data *ldata) { - mutex_lock(&tty->echo_lock); - - add_echo_byte(ECHO_OP_START, tty); - add_echo_byte(ECHO_OP_SET_CANON_COL, tty); - - mutex_unlock(&tty->echo_lock); + add_echo_byte(ECHO_OP_START, ldata); + add_echo_byte(ECHO_OP_SET_CANON_COL, ldata); } /** * echo_erase_tab - add operation to erase a tab * @num_chars: number of character columns already used * @after_tab: true if num_chars starts after a previous tab - * @tty: terminal device + * @ldata: n_tty data * * Add an operation to the echo buffer to erase a tab. * @@ -741,17 +897,13 @@ static void echo_set_canon_col(struct tty_struct *tty) * of input. This information will be used later, along with * canon column (if applicable), to go back the correct number * of columns. - * - * Locking: echo_lock to protect the echo buffer */ static void echo_erase_tab(unsigned int num_chars, int after_tab, - struct tty_struct *tty) + struct n_tty_data *ldata) { - mutex_lock(&tty->echo_lock); - - add_echo_byte(ECHO_OP_START, tty); - add_echo_byte(ECHO_OP_ERASE_TAB, tty); + add_echo_byte(ECHO_OP_START, ldata); + add_echo_byte(ECHO_OP_ERASE_TAB, ldata); /* We only need to know this modulo 8 (tab spacing) */ num_chars &= 7; @@ -760,9 +912,7 @@ static void echo_erase_tab(unsigned int num_chars, int after_tab, if (after_tab) num_chars |= 0x80; - add_echo_byte(num_chars, tty); - - mutex_unlock(&tty->echo_lock); + add_echo_byte(num_chars, ldata); } /** @@ -774,22 +924,16 @@ static void echo_erase_tab(unsigned int num_chars, int after_tab, * L_ECHO(tty) is true. Called from the driver receive_buf path. * * This variant does not treat control characters specially. - * - * Locking: echo_lock to protect the echo buffer */ -static void echo_char_raw(unsigned char c, struct tty_struct *tty) +static void echo_char_raw(unsigned char c, struct n_tty_data *ldata) { - mutex_lock(&tty->echo_lock); - if (c == ECHO_OP_START) { - add_echo_byte(ECHO_OP_START, tty); - add_echo_byte(ECHO_OP_START, tty); + add_echo_byte(ECHO_OP_START, ldata); + add_echo_byte(ECHO_OP_START, ldata); } else { - add_echo_byte(c, tty); + add_echo_byte(c, ldata); } - - mutex_unlock(&tty->echo_lock); } /** @@ -802,36 +946,32 @@ static void echo_char_raw(unsigned char c, struct tty_struct *tty) * * This variant tags control characters to be echoed as "^X" * (where X is the letter representing the control char). - * - * Locking: echo_lock to protect the echo buffer */ static void echo_char(unsigned char c, struct tty_struct *tty) { - mutex_lock(&tty->echo_lock); + struct n_tty_data *ldata = tty->disc_data; if (c == ECHO_OP_START) { - add_echo_byte(ECHO_OP_START, tty); - add_echo_byte(ECHO_OP_START, tty); + add_echo_byte(ECHO_OP_START, ldata); + add_echo_byte(ECHO_OP_START, ldata); } else { if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') - add_echo_byte(ECHO_OP_START, tty); - add_echo_byte(c, tty); + add_echo_byte(ECHO_OP_START, ldata); + add_echo_byte(c, ldata); } - - mutex_unlock(&tty->echo_lock); } /** * finish_erasing - complete erase - * @tty: tty doing the erase + * @ldata: n_tty data */ -static inline void finish_erasing(struct tty_struct *tty) +static inline void finish_erasing(struct n_tty_data *ldata) { - if (tty->erasing) { - echo_char_raw('/', tty); - tty->erasing = 0; + if (ldata->erasing) { + echo_char_raw('/', ldata); + ldata->erasing = 0; } } @@ -844,17 +984,23 @@ static inline void finish_erasing(struct tty_struct *tty) * present in the stream from the driver layer. Handles the complexities * of UTF-8 multibyte symbols. * - * Locking: read_lock for tty buffers + * n_tty_receive_buf()/producer path: + * caller holds non-exclusive termios_rwsem + * modifies read_head + * + * Modifying the read_head is not considered a publish in this context + * because canonical mode is active -- only canon_head publishes */ static void eraser(unsigned char c, struct tty_struct *tty) { + struct n_tty_data *ldata = tty->disc_data; enum { ERASE, WERASE, KILL } kill_type; - int head, seen_alnums, cnt; - unsigned long flags; + size_t head; + size_t cnt; + int seen_alnums; - /* FIXME: locking needed ? */ - if (tty->read_head == tty->canon_head) { + if (ldata->read_head == ldata->canon_head) { /* process_output('\a', tty); */ /* what do you think? */ return; } @@ -864,39 +1010,30 @@ static void eraser(unsigned char c, struct tty_struct *tty) kill_type = WERASE; else { if (!L_ECHO(tty)) { - spin_lock_irqsave(&tty->read_lock, flags); - tty->read_cnt -= ((tty->read_head - tty->canon_head) & - (N_TTY_BUF_SIZE - 1)); - tty->read_head = tty->canon_head; - spin_unlock_irqrestore(&tty->read_lock, flags); + ldata->read_head = ldata->canon_head; return; } if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { - spin_lock_irqsave(&tty->read_lock, flags); - tty->read_cnt -= ((tty->read_head - tty->canon_head) & - (N_TTY_BUF_SIZE - 1)); - tty->read_head = tty->canon_head; - spin_unlock_irqrestore(&tty->read_lock, flags); - finish_erasing(tty); + ldata->read_head = ldata->canon_head; + finish_erasing(ldata); echo_char(KILL_CHAR(tty), tty); /* Add a newline if ECHOK is on and ECHOKE is off. */ if (L_ECHOK(tty)) - echo_char_raw('\n', tty); + echo_char_raw('\n', ldata); return; } kill_type = KILL; } seen_alnums = 0; - /* FIXME: Locking ?? */ - while (tty->read_head != tty->canon_head) { - head = tty->read_head; + while (ldata->read_head != ldata->canon_head) { + head = ldata->read_head; /* erase a single possibly multibyte character */ do { - head = (head - 1) & (N_TTY_BUF_SIZE-1); - c = tty->read_buf[head]; - } while (is_continuation(c, tty) && head != tty->canon_head); + head--; + c = read_buf(ldata, head); + } while (is_continuation(c, tty) && head != ldata->canon_head); /* do not partially erase */ if (is_continuation(c, tty)) @@ -909,30 +1046,27 @@ static void eraser(unsigned char c, struct tty_struct *tty) else if (seen_alnums) break; } - cnt = (tty->read_head - head) & (N_TTY_BUF_SIZE-1); - spin_lock_irqsave(&tty->read_lock, flags); - tty->read_head = head; - tty->read_cnt -= cnt; - spin_unlock_irqrestore(&tty->read_lock, flags); + cnt = ldata->read_head - head; + ldata->read_head = head; if (L_ECHO(tty)) { if (L_ECHOPRT(tty)) { - if (!tty->erasing) { - echo_char_raw('\\', tty); - tty->erasing = 1; + if (!ldata->erasing) { + echo_char_raw('\\', ldata); + ldata->erasing = 1; } /* if cnt > 1, output a multi-byte character */ echo_char(c, tty); while (--cnt > 0) { - head = (head+1) & (N_TTY_BUF_SIZE-1); - echo_char_raw(tty->read_buf[head], tty); - echo_move_back_col(tty); + head++; + echo_char_raw(read_buf(ldata, head), ldata); + echo_move_back_col(ldata); } } else if (kill_type == ERASE && !L_ECHOE(tty)) { echo_char(ERASE_CHAR(tty), tty); } else if (c == '\t') { unsigned int num_chars = 0; int after_tab = 0; - unsigned long tail = tty->read_head; + size_t tail = ldata->read_head; /* * Count the columns used for characters @@ -941,9 +1075,9 @@ static void eraser(unsigned char c, struct tty_struct *tty) * This info is used to go back the correct * number of columns. */ - while (tail != tty->canon_head) { - tail = (tail-1) & (N_TTY_BUF_SIZE-1); - c = tty->read_buf[tail]; + while (tail != ldata->canon_head) { + tail--; + c = read_buf(ldata, tail); if (c == '\t') { after_tab = 1; break; @@ -954,48 +1088,44 @@ static void eraser(unsigned char c, struct tty_struct *tty) num_chars++; } } - echo_erase_tab(num_chars, after_tab, tty); + echo_erase_tab(num_chars, after_tab, ldata); } else { if (iscntrl(c) && L_ECHOCTL(tty)) { - echo_char_raw('\b', tty); - echo_char_raw(' ', tty); - echo_char_raw('\b', tty); + echo_char_raw('\b', ldata); + echo_char_raw(' ', ldata); + echo_char_raw('\b', ldata); } if (!iscntrl(c) || L_ECHOCTL(tty)) { - echo_char_raw('\b', tty); - echo_char_raw(' ', tty); - echo_char_raw('\b', tty); + echo_char_raw('\b', ldata); + echo_char_raw(' ', ldata); + echo_char_raw('\b', ldata); } } } if (kill_type == ERASE) break; } - if (tty->read_head == tty->canon_head && L_ECHO(tty)) - finish_erasing(tty); + if (ldata->read_head == ldata->canon_head && L_ECHO(tty)) + finish_erasing(ldata); } /** * 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. + * Called when a signal is being sent due to terminal input. + * Called from the driver receive_buf path so serialized. * - * Locking: ctrl_lock, read_lock (both via flush buffer) + * Locking: ctrl_lock */ -static inline void isig(int sig, struct tty_struct *tty, int flush) +static void isig(int sig, struct tty_struct *tty) { - if (tty->pgrp) - kill_pgrp(tty->pgrp, sig, 1); - if (flush || !L_NOFLSH(tty)) { - n_tty_flush_buffer(tty); - tty_driver_flush_buffer(tty); + struct pid *tty_pgrp = tty_get_pgrp(tty); + if (tty_pgrp) { + kill_pgrp(tty_pgrp, sig, 1); + put_pid(tty_pgrp); } } @@ -1006,23 +1136,37 @@ static inline void isig(int sig, struct tty_struct *tty, int flush) * 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. + * n_tty_receive_buf()/producer path: + * caller holds non-exclusive termios_rwsem + * publishes read_head via put_tty_queue() + * + * Note: may get exclusive termios_rwsem if flushing input buffer */ -static inline void n_tty_receive_break(struct tty_struct *tty) +static void n_tty_receive_break(struct tty_struct *tty) { + struct n_tty_data *ldata = tty->disc_data; + if (I_IGNBRK(tty)) return; if (I_BRKINT(tty)) { - isig(SIGINT, tty, 1); + isig(SIGINT, tty); + if (!L_NOFLSH(tty)) { + /* flushing needs exclusive termios_rwsem */ + up_read(&tty->termios_rwsem); + n_tty_flush_buffer(tty); + tty_driver_flush_buffer(tty); + down_read(&tty->termios_rwsem); + } return; } if (I_PARMRK(tty)) { - put_tty_queue('\377', tty); - put_tty_queue('\0', tty); + put_tty_queue('\377', ldata); + put_tty_queue('\0', ldata); } - put_tty_queue('\0', tty); - wake_up_interruptible(&tty->read_wait); + put_tty_queue('\0', ldata); + if (waitqueue_active(&tty->read_wait)) + wake_up_interruptible(&tty->read_wait); } /** @@ -1038,18 +1182,19 @@ static inline void n_tty_receive_break(struct tty_struct *tty) * private. */ -static inline void n_tty_receive_overrun(struct tty_struct *tty) +static void n_tty_receive_overrun(struct tty_struct *tty) { + struct n_tty_data *ldata = tty->disc_data; char buf[64]; - tty->num_overrun++; - if (time_before(tty->overrun_time, jiffies - HZ) || - time_after(tty->overrun_time, jiffies)) { + ldata->num_overrun++; + if (time_after(jiffies, ldata->overrun_time + HZ) || + time_after(ldata->overrun_time, jiffies)) { printk(KERN_WARNING "%s: %d input overrun(s)\n", tty_name(tty, buf), - tty->num_overrun); - tty->overrun_time = jiffies; - tty->num_overrun = 0; + ldata->num_overrun); + ldata->overrun_time = jiffies; + ldata->num_overrun = 0; } } @@ -1059,22 +1204,50 @@ static inline void n_tty_receive_overrun(struct tty_struct *tty) * @c: character * * Process a parity error and queue the right data to indicate - * the error case if necessary. Locking as per n_tty_receive_buf. + * the error case if necessary. + * + * n_tty_receive_buf()/producer path: + * caller holds non-exclusive termios_rwsem + * publishes read_head via put_tty_queue() */ -static inline void n_tty_receive_parity_error(struct tty_struct *tty, - unsigned char c) +static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c) { - if (I_IGNPAR(tty)) - return; - if (I_PARMRK(tty)) { - put_tty_queue('\377', tty); - put_tty_queue('\0', tty); - put_tty_queue(c, tty); - } else if (I_INPCK(tty)) - put_tty_queue('\0', tty); - else - put_tty_queue(c, tty); - wake_up_interruptible(&tty->read_wait); + struct n_tty_data *ldata = tty->disc_data; + + if (I_INPCK(tty)) { + if (I_IGNPAR(tty)) + return; + if (I_PARMRK(tty)) { + put_tty_queue('\377', ldata); + put_tty_queue('\0', ldata); + put_tty_queue(c, ldata); + } else + put_tty_queue('\0', ldata); + } else + put_tty_queue(c, ldata); + if (waitqueue_active(&tty->read_wait)) + wake_up_interruptible(&tty->read_wait); +} + +static void +n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c) +{ + if (!L_NOFLSH(tty)) { + /* flushing needs exclusive termios_rwsem */ + up_read(&tty->termios_rwsem); + n_tty_flush_buffer(tty); + tty_driver_flush_buffer(tty); + down_read(&tty->termios_rwsem); + } + if (I_IXON(tty)) + start_tty(tty); + if (L_ECHO(tty)) { + echo_char(c, tty); + commit_echoes(tty); + } else + process_echoes(tty); + isig(signal, tty); + return; } /** @@ -1085,260 +1258,257 @@ static inline void n_tty_receive_parity_error(struct tty_struct *tty, * Process an individual character of input received from the driver. * This is serialized with respect to itself by the rules for the * driver above. + * + * n_tty_receive_buf()/producer path: + * caller holds non-exclusive termios_rwsem + * publishes canon_head if canonical mode is active + * otherwise, publishes read_head via put_tty_queue() + * + * Returns 1 if LNEXT was received, else returns 0 */ -static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c) +static int +n_tty_receive_char_special(struct tty_struct *tty, unsigned char c) { - unsigned long flags; - int parmrk; - - if (tty->raw) { - put_tty_queue(c, tty); - return; - } - - if (I_ISTRIP(tty)) - c &= 0x7f; - if (I_IUCLC(tty) && L_IEXTEN(tty)) - c = tolower(c); - - if (L_EXTPROC(tty)) { - put_tty_queue(c, tty); - return; - } - - if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && - I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty) && - c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && c != SUSP_CHAR(tty)) { - start_tty(tty); - process_echoes(tty); - } - - if (tty->closing) { - if (I_IXON(tty)) { - if (c == START_CHAR(tty)) { - start_tty(tty); - process_echoes(tty); - } else if (c == STOP_CHAR(tty)) - stop_tty(tty); - } - return; - } - - /* - * If the previous character was LNEXT, or we know that this - * character is not one of the characters that we'll have to - * handle specially, do shortcut processing to speed things - * up. - */ - if (!test_bit(c, tty->process_char_map) || tty->lnext) { - tty->lnext = 0; - parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; - if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) { - /* beep if no space */ - if (L_ECHO(tty)) - process_output('\a', tty); - return; - } - if (L_ECHO(tty)) { - finish_erasing(tty); - /* Record the column of first canon char. */ - if (tty->canon_head == tty->read_head) - echo_set_canon_col(tty); - echo_char(c, tty); - process_echoes(tty); - } - if (parmrk) - put_tty_queue(c, tty); - put_tty_queue(c, tty); - return; - } + struct n_tty_data *ldata = tty->disc_data; if (I_IXON(tty)) { if (c == START_CHAR(tty)) { start_tty(tty); process_echoes(tty); - return; + return 0; } if (c == STOP_CHAR(tty)) { stop_tty(tty); - return; + return 0; } } if (L_ISIG(tty)) { - int signal; - signal = SIGINT; - if (c == INTR_CHAR(tty)) - goto send_signal; - signal = SIGQUIT; - if (c == QUIT_CHAR(tty)) - goto send_signal; - signal = SIGTSTP; - if (c == SUSP_CHAR(tty)) { -send_signal: - /* - * Note that we do not use isig() here because we want - * the order to be: - * 1) flush, 2) echo, 3) signal - */ - if (!L_NOFLSH(tty)) { - n_tty_flush_buffer(tty); - tty_driver_flush_buffer(tty); - } - if (I_IXON(tty)) - start_tty(tty); - if (L_ECHO(tty)) { - echo_char(c, tty); - process_echoes(tty); - } - if (tty->pgrp) - kill_pgrp(tty->pgrp, signal, 1); - return; + if (c == INTR_CHAR(tty)) { + n_tty_receive_signal_char(tty, SIGINT, c); + return 0; + } else if (c == QUIT_CHAR(tty)) { + n_tty_receive_signal_char(tty, SIGQUIT, c); + return 0; + } else if (c == SUSP_CHAR(tty)) { + n_tty_receive_signal_char(tty, SIGTSTP, c); + return 0; } } + if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { + start_tty(tty); + process_echoes(tty); + } + if (c == '\r') { if (I_IGNCR(tty)) - return; + return 0; if (I_ICRNL(tty)) c = '\n'; } else if (c == '\n' && I_INLCR(tty)) c = '\r'; - if (tty->icanon) { + if (ldata->icanon) { if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { eraser(c, tty); - process_echoes(tty); - return; + commit_echoes(tty); + return 0; } if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { - tty->lnext = 1; + ldata->lnext = 1; if (L_ECHO(tty)) { - finish_erasing(tty); + finish_erasing(ldata); if (L_ECHOCTL(tty)) { - echo_char_raw('^', tty); - echo_char_raw('\b', tty); - process_echoes(tty); + echo_char_raw('^', ldata); + echo_char_raw('\b', ldata); + commit_echoes(tty); } } - return; + return 1; } - if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && - L_IEXTEN(tty)) { - unsigned long tail = tty->canon_head; + if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && L_IEXTEN(tty)) { + size_t tail = ldata->canon_head; - finish_erasing(tty); + finish_erasing(ldata); echo_char(c, tty); - echo_char_raw('\n', tty); - while (tail != tty->read_head) { - echo_char(tty->read_buf[tail], tty); - tail = (tail+1) & (N_TTY_BUF_SIZE-1); + echo_char_raw('\n', ldata); + while (tail != ldata->read_head) { + echo_char(read_buf(ldata, tail), tty); + tail++; } - process_echoes(tty); - return; + commit_echoes(tty); + return 0; } if (c == '\n') { - if (tty->read_cnt >= N_TTY_BUF_SIZE) { - if (L_ECHO(tty)) - process_output('\a', tty); - return; - } if (L_ECHO(tty) || L_ECHONL(tty)) { - echo_char_raw('\n', tty); - process_echoes(tty); + echo_char_raw('\n', ldata); + commit_echoes(tty); } goto handle_newline; } if (c == EOF_CHAR(tty)) { - if (tty->read_cnt >= N_TTY_BUF_SIZE) - return; - if (tty->canon_head != tty->read_head) - set_bit(TTY_PUSH, &tty->flags); c = __DISABLED_CHAR; goto handle_newline; } if ((c == EOL_CHAR(tty)) || (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { - parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) - ? 1 : 0; - if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk)) { - if (L_ECHO(tty)) - process_output('\a', tty); - return; - } /* * XXX are EOL_CHAR and EOL2_CHAR echoed?!? */ if (L_ECHO(tty)) { /* Record the column of first canon char. */ - if (tty->canon_head == tty->read_head) - echo_set_canon_col(tty); + if (ldata->canon_head == ldata->read_head) + echo_set_canon_col(ldata); echo_char(c, tty); - process_echoes(tty); + commit_echoes(tty); } /* * XXX does PARMRK doubling happen for * EOL_CHAR and EOL2_CHAR? */ - if (parmrk) - put_tty_queue(c, tty); + if (c == (unsigned char) '\377' && I_PARMRK(tty)) + put_tty_queue(c, ldata); handle_newline: - spin_lock_irqsave(&tty->read_lock, flags); - set_bit(tty->read_head, tty->read_flags); - put_tty_queue_nolock(c, tty); - tty->canon_head = tty->read_head; - tty->canon_data++; - spin_unlock_irqrestore(&tty->read_lock, flags); + set_bit(ldata->read_head & (N_TTY_BUF_SIZE - 1), ldata->read_flags); + put_tty_queue(c, ldata); + ldata->canon_head = ldata->read_head; kill_fasync(&tty->fasync, SIGIO, POLL_IN); if (waitqueue_active(&tty->read_wait)) wake_up_interruptible(&tty->read_wait); - return; + return 0; } } - parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; - if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) { - /* beep if no space */ - if (L_ECHO(tty)) - process_output('\a', tty); - return; - } if (L_ECHO(tty)) { - finish_erasing(tty); + finish_erasing(ldata); if (c == '\n') - echo_char_raw('\n', tty); + echo_char_raw('\n', ldata); else { /* Record the column of first canon char. */ - if (tty->canon_head == tty->read_head) - echo_set_canon_col(tty); + if (ldata->canon_head == ldata->read_head) + echo_set_canon_col(ldata); echo_char(c, tty); } + commit_echoes(tty); + } + + /* PARMRK doubling check */ + if (c == (unsigned char) '\377' && I_PARMRK(tty)) + put_tty_queue(c, ldata); + + put_tty_queue(c, ldata); + return 0; +} + +static inline void +n_tty_receive_char_inline(struct tty_struct *tty, unsigned char c) +{ + struct n_tty_data *ldata = tty->disc_data; + + if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { + start_tty(tty); process_echoes(tty); } + if (L_ECHO(tty)) { + finish_erasing(ldata); + /* Record the column of first canon char. */ + if (ldata->canon_head == ldata->read_head) + echo_set_canon_col(ldata); + echo_char(c, tty); + commit_echoes(tty); + } + /* PARMRK doubling check */ + if (c == (unsigned char) '\377' && I_PARMRK(tty)) + put_tty_queue(c, ldata); + put_tty_queue(c, ldata); +} - if (parmrk) - put_tty_queue(c, tty); +static void n_tty_receive_char(struct tty_struct *tty, unsigned char c) +{ + n_tty_receive_char_inline(tty, c); +} - put_tty_queue(c, tty); +static inline void +n_tty_receive_char_fast(struct tty_struct *tty, unsigned char c) +{ + struct n_tty_data *ldata = tty->disc_data; + + if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) { + start_tty(tty); + process_echoes(tty); + } + if (L_ECHO(tty)) { + finish_erasing(ldata); + /* Record the column of first canon char. */ + if (ldata->canon_head == ldata->read_head) + echo_set_canon_col(ldata); + echo_char(c, tty); + commit_echoes(tty); + } + put_tty_queue(c, ldata); } +static void n_tty_receive_char_closing(struct tty_struct *tty, unsigned char c) +{ + if (I_ISTRIP(tty)) + c &= 0x7f; + if (I_IUCLC(tty) && L_IEXTEN(tty)) + c = tolower(c); -/** - * 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 - */ + if (I_IXON(tty)) { + if (c == STOP_CHAR(tty)) + stop_tty(tty); + else if (c == START_CHAR(tty) || + (tty->stopped && !tty->flow_stopped && I_IXANY(tty) && + c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && + c != SUSP_CHAR(tty))) { + start_tty(tty); + process_echoes(tty); + } + } +} -static void n_tty_write_wakeup(struct tty_struct *tty) +static void +n_tty_receive_char_flagged(struct tty_struct *tty, unsigned char c, char flag) { - if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) - kill_fasync(&tty->fasync, SIGIO, POLL_OUT); + char buf[64]; + + switch (flag) { + case TTY_BREAK: + n_tty_receive_break(tty); + break; + case TTY_PARITY: + case TTY_FRAME: + n_tty_receive_parity_error(tty, c); + break; + case TTY_OVERRUN: + n_tty_receive_overrun(tty); + break; + default: + printk(KERN_ERR "%s: unknown flag %d\n", + tty_name(tty, buf), flag); + break; + } +} + +static void +n_tty_receive_char_lnext(struct tty_struct *tty, unsigned char c, char flag) +{ + struct n_tty_data *ldata = tty->disc_data; + + ldata->lnext = 0; + if (likely(flag == TTY_NORMAL)) { + if (I_ISTRIP(tty)) + c &= 0x7f; + if (I_IUCLC(tty) && L_IEXTEN(tty)) + c = tolower(c); + n_tty_receive_char(tty, c); + } else + n_tty_receive_char_flagged(tty, c, flag); } /** @@ -1352,82 +1522,209 @@ static void n_tty_write_wakeup(struct tty_struct *tty) * 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) + * + * n_tty_receive_buf()/producer path: + * claims non-exclusive termios_rwsem + * publishes read_head and canon_head */ -static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, - char *fp, int count) +static void +n_tty_receive_buf_real_raw(struct tty_struct *tty, const unsigned char *cp, + char *fp, int count) { - const unsigned char *p; - char *f, flags = TTY_NORMAL; - int i; - char buf[64]; - unsigned long cpuflags; + struct n_tty_data *ldata = tty->disc_data; + size_t n, head; + + head = ldata->read_head & (N_TTY_BUF_SIZE - 1); + n = N_TTY_BUF_SIZE - max(read_cnt(ldata), head); + n = min_t(size_t, count, n); + memcpy(read_buf_addr(ldata, head), cp, n); + ldata->read_head += n; + cp += n; + count -= n; + + head = ldata->read_head & (N_TTY_BUF_SIZE - 1); + n = N_TTY_BUF_SIZE - max(read_cnt(ldata), head); + n = min_t(size_t, count, n); + memcpy(read_buf_addr(ldata, head), cp, n); + ldata->read_head += n; +} - if (!tty->read_buf) - return; +static void +n_tty_receive_buf_raw(struct tty_struct *tty, const unsigned char *cp, + char *fp, int count) +{ + struct n_tty_data *ldata = tty->disc_data; + char flag = TTY_NORMAL; + + while (count--) { + if (fp) + flag = *fp++; + if (likely(flag == TTY_NORMAL)) + put_tty_queue(*cp++, ldata); + else + n_tty_receive_char_flagged(tty, *cp++, flag); + } +} - if (tty->real_raw) { - spin_lock_irqsave(&tty->read_lock, cpuflags); - i = min(N_TTY_BUF_SIZE - tty->read_cnt, - N_TTY_BUF_SIZE - tty->read_head); - i = min(count, i); - memcpy(tty->read_buf + tty->read_head, cp, i); - tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1); - tty->read_cnt += i; - cp += i; - count -= i; - - i = min(N_TTY_BUF_SIZE - tty->read_cnt, - N_TTY_BUF_SIZE - tty->read_head); - i = min(count, i); - memcpy(tty->read_buf + tty->read_head, cp, i); - tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1); - tty->read_cnt += i; - spin_unlock_irqrestore(&tty->read_lock, cpuflags); - } else { - for (i = count, p = cp, f = fp; i; i--, p++) { - if (f) - flags = *f++; - switch (flags) { - case TTY_NORMAL: - n_tty_receive_char(tty, *p); - break; - case TTY_BREAK: - n_tty_receive_break(tty); - break; - case TTY_PARITY: - case TTY_FRAME: - n_tty_receive_parity_error(tty, *p); - break; - case TTY_OVERRUN: - n_tty_receive_overrun(tty); - break; - default: - printk(KERN_ERR "%s: unknown flag %d\n", - tty_name(tty, buf), flags); - break; +static void +n_tty_receive_buf_closing(struct tty_struct *tty, const unsigned char *cp, + char *fp, int count) +{ + char flag = TTY_NORMAL; + + while (count--) { + if (fp) + flag = *fp++; + if (likely(flag == TTY_NORMAL)) + n_tty_receive_char_closing(tty, *cp++); + else + n_tty_receive_char_flagged(tty, *cp++, flag); + } +} + +static void +n_tty_receive_buf_standard(struct tty_struct *tty, const unsigned char *cp, + char *fp, int count) +{ + struct n_tty_data *ldata = tty->disc_data; + char flag = TTY_NORMAL; + + while (count--) { + if (fp) + flag = *fp++; + if (likely(flag == TTY_NORMAL)) { + unsigned char c = *cp++; + + if (I_ISTRIP(tty)) + c &= 0x7f; + if (I_IUCLC(tty) && L_IEXTEN(tty)) + c = tolower(c); + if (L_EXTPROC(tty)) { + put_tty_queue(c, ldata); + continue; + } + if (!test_bit(c, ldata->char_map)) + n_tty_receive_char_inline(tty, c); + else if (n_tty_receive_char_special(tty, c) && count) { + if (fp) + flag = *fp++; + n_tty_receive_char_lnext(tty, *cp++, flag); + count--; + } + } else + n_tty_receive_char_flagged(tty, *cp++, flag); + } +} + +static void +n_tty_receive_buf_fast(struct tty_struct *tty, const unsigned char *cp, + char *fp, int count) +{ + struct n_tty_data *ldata = tty->disc_data; + char flag = TTY_NORMAL; + + while (count--) { + if (fp) + flag = *fp++; + if (likely(flag == TTY_NORMAL)) { + unsigned char c = *cp++; + + if (!test_bit(c, ldata->char_map)) + n_tty_receive_char_fast(tty, c); + else if (n_tty_receive_char_special(tty, c) && count) { + if (fp) + flag = *fp++; + n_tty_receive_char_lnext(tty, *cp++, flag); + count--; } + } else + n_tty_receive_char_flagged(tty, *cp++, flag); + } +} + +static void __receive_buf(struct tty_struct *tty, const unsigned char *cp, + char *fp, int count) +{ + struct n_tty_data *ldata = tty->disc_data; + bool preops = I_ISTRIP(tty) || (I_IUCLC(tty) && L_IEXTEN(tty)); + + if (ldata->real_raw) + n_tty_receive_buf_real_raw(tty, cp, fp, count); + else if (ldata->raw || (L_EXTPROC(tty) && !preops)) + n_tty_receive_buf_raw(tty, cp, fp, count); + else if (tty->closing && !L_EXTPROC(tty)) + n_tty_receive_buf_closing(tty, cp, fp, count); + else { + if (ldata->lnext) { + char flag = TTY_NORMAL; + + if (fp) + flag = *fp++; + n_tty_receive_char_lnext(tty, *cp++, flag); + count--; } + + if (!preops && !I_PARMRK(tty)) + n_tty_receive_buf_fast(tty, cp, fp, count); + else + n_tty_receive_buf_standard(tty, cp, fp, count); + + flush_echoes(tty); if (tty->ops->flush_chars) tty->ops->flush_chars(tty); } - n_tty_set_room(tty); - - if ((!tty->icanon && (tty->read_cnt >= tty->minimum_to_wake)) || + if ((!ldata->icanon && (read_cnt(ldata) >= ldata->minimum_to_wake)) || L_EXTPROC(tty)) { kill_fasync(&tty->fasync, SIGIO, POLL_IN); if (waitqueue_active(&tty->read_wait)) wake_up_interruptible(&tty->read_wait); } +} - /* - * Check the remaining room for the input canonicalization - * mode. We don't want to throttle the driver if we're in - * canonical mode and don't have a newline yet! - */ - if (tty->receive_room < TTY_THRESHOLD_THROTTLE) - tty_throttle(tty); +static int +n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp, + char *fp, int count, int flow) +{ + struct n_tty_data *ldata = tty->disc_data; + int room, n, rcvd = 0; + + down_read(&tty->termios_rwsem); + + while (1) { + room = receive_room(tty); + n = min(count, room); + if (!n) { + if (flow && !room) + ldata->no_room = 1; + break; + } + __receive_buf(tty, cp, fp, n); + cp += n; + if (fp) + fp += n; + count -= n; + rcvd += n; + } + + tty->receive_room = room; + n_tty_check_throttle(tty); + up_read(&tty->termios_rwsem); + + return rcvd; +} + +static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, + char *fp, int count) +{ + n_tty_receive_buf_common(tty, cp, fp, count, 0); +} + +static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp, + char *fp, int count) +{ + return n_tty_receive_buf_common(tty, cp, fp, count, 1); } int is_ignored(int sig) @@ -1447,87 +1744,93 @@ int is_ignored(int sig) * guaranteed that this function will not be re-entered or in progress * when the ldisc is closed. * - * Locking: Caller holds tty->termios_mutex + * Locking: Caller holds tty->termios_rwsem */ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) { - 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; + struct n_tty_data *ldata = tty->disc_data; + + if (!old || (old->c_lflag ^ tty->termios.c_lflag) & ICANON) { + bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); + ldata->line_start = ldata->read_tail; + if (!L_ICANON(tty) || !read_cnt(ldata)) { + ldata->canon_head = ldata->read_tail; + ldata->push = 0; + } else { + set_bit((ldata->read_head - 1) & (N_TTY_BUF_SIZE - 1), + ldata->read_flags); + ldata->canon_head = ldata->read_head; + ldata->push = 1; + } + ldata->erasing = 0; + ldata->lnext = 0; } - if (canon_change && !L_ICANON(tty) && tty->read_cnt) - wake_up_interruptible(&tty->read_wait); + ldata->icanon = (L_ICANON(tty) != 0); - tty->icanon = (L_ICANON(tty) != 0); - if (test_bit(TTY_HW_COOK_IN, &tty->flags)) { - tty->raw = 1; - tty->real_raw = 1; - n_tty_set_room(tty); - return; - } if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || I_PARMRK(tty)) { - memset(tty->process_char_map, 0, 256/8); + bitmap_zero(ldata->char_map, 256); if (I_IGNCR(tty) || I_ICRNL(tty)) - set_bit('\r', tty->process_char_map); + set_bit('\r', ldata->char_map); if (I_INLCR(tty)) - set_bit('\n', tty->process_char_map); + set_bit('\n', ldata->char_map); if (L_ICANON(tty)) { - set_bit(ERASE_CHAR(tty), tty->process_char_map); - set_bit(KILL_CHAR(tty), tty->process_char_map); - set_bit(EOF_CHAR(tty), tty->process_char_map); - set_bit('\n', tty->process_char_map); - set_bit(EOL_CHAR(tty), tty->process_char_map); + set_bit(ERASE_CHAR(tty), ldata->char_map); + set_bit(KILL_CHAR(tty), ldata->char_map); + set_bit(EOF_CHAR(tty), ldata->char_map); + set_bit('\n', ldata->char_map); + set_bit(EOL_CHAR(tty), ldata->char_map); if (L_IEXTEN(tty)) { - set_bit(WERASE_CHAR(tty), - tty->process_char_map); - set_bit(LNEXT_CHAR(tty), - tty->process_char_map); - set_bit(EOL2_CHAR(tty), - tty->process_char_map); + set_bit(WERASE_CHAR(tty), ldata->char_map); + set_bit(LNEXT_CHAR(tty), ldata->char_map); + set_bit(EOL2_CHAR(tty), ldata->char_map); if (L_ECHO(tty)) set_bit(REPRINT_CHAR(tty), - tty->process_char_map); + ldata->char_map); } } if (I_IXON(tty)) { - set_bit(START_CHAR(tty), tty->process_char_map); - set_bit(STOP_CHAR(tty), tty->process_char_map); + set_bit(START_CHAR(tty), ldata->char_map); + set_bit(STOP_CHAR(tty), ldata->char_map); } if (L_ISIG(tty)) { - set_bit(INTR_CHAR(tty), tty->process_char_map); - set_bit(QUIT_CHAR(tty), tty->process_char_map); - set_bit(SUSP_CHAR(tty), tty->process_char_map); + set_bit(INTR_CHAR(tty), ldata->char_map); + set_bit(QUIT_CHAR(tty), ldata->char_map); + set_bit(SUSP_CHAR(tty), ldata->char_map); } - clear_bit(__DISABLED_CHAR, tty->process_char_map); - tty->raw = 0; - tty->real_raw = 0; + clear_bit(__DISABLED_CHAR, ldata->char_map); + ldata->raw = 0; + ldata->real_raw = 0; } else { - tty->raw = 1; + ldata->raw = 1; if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && (I_IGNPAR(tty) || !I_INPCK(tty)) && (tty->driver->flags & TTY_DRIVER_REAL_RAW)) - tty->real_raw = 1; + ldata->real_raw = 1; else - tty->real_raw = 0; + ldata->real_raw = 0; } n_tty_set_room(tty); + /* + * Fix tty hang when I_IXON(tty) is cleared, but the tty + * been stopped by STOP_CHAR(tty) before it. + */ + if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) { + start_tty(tty); + process_echoes(tty); + } + /* The termios change make the tty ready for I/O */ - wake_up_interruptible(&tty->write_wait); - wake_up_interruptible(&tty->read_wait); + if (waitqueue_active(&tty->write_wait)) + wake_up_interruptible(&tty->write_wait); + if (waitqueue_active(&tty->read_wait)) + wake_up_interruptible(&tty->read_wait); } /** @@ -1542,15 +1845,13 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) static void n_tty_close(struct tty_struct *tty) { - n_tty_flush_buffer(tty); - if (tty->read_buf) { - kfree(tty->read_buf); - tty->read_buf = NULL; - } - if (tty->echo_buf) { - kfree(tty->echo_buf); - tty->echo_buf = NULL; - } + struct n_tty_data *ldata = tty->disc_data; + + if (tty->link) + n_tty_packet_mode_flush(tty); + + vfree(ldata); + tty->disc_data = NULL; } /** @@ -1565,43 +1866,49 @@ static void n_tty_close(struct tty_struct *tty) static int n_tty_open(struct tty_struct *tty) { - if (!tty) - return -EINVAL; - - /* These are ugly. Currently a malloc failure here can panic */ - if (!tty->read_buf) { - tty->read_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); - if (!tty->read_buf) - return -ENOMEM; - } - if (!tty->echo_buf) { - tty->echo_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); - - if (!tty->echo_buf) - return -ENOMEM; - } - reset_buffer_flags(tty); - tty->column = 0; - n_tty_set_termios(tty, NULL); - tty->minimum_to_wake = 1; + struct n_tty_data *ldata; + + /* Currently a malloc failure here can panic */ + ldata = vmalloc(sizeof(*ldata)); + if (!ldata) + goto err; + + ldata->overrun_time = jiffies; + mutex_init(&ldata->atomic_read_lock); + mutex_init(&ldata->output_lock); + + tty->disc_data = ldata; + reset_buffer_flags(tty->disc_data); + ldata->column = 0; + ldata->canon_column = 0; + ldata->minimum_to_wake = 1; + ldata->num_overrun = 0; + ldata->no_room = 0; + ldata->lnext = 0; tty->closing = 0; + /* indicate buffer work may resume */ + clear_bit(TTY_LDISC_HALTED, &tty->flags); + n_tty_set_termios(tty, NULL); + tty_unthrottle(tty); + return 0; +err: + return -ENOMEM; } -static inline int input_available_p(struct tty_struct *tty, int amt) +static inline int input_available_p(struct tty_struct *tty, int poll) { - tty_flush_to_ldisc(tty); - if (tty->icanon && !L_EXTPROC(tty)) { - if (tty->canon_data) - return 1; - } else if (tty->read_cnt >= (amt ? amt : 1)) - return 1; + struct n_tty_data *ldata = tty->disc_data; + int amt = poll && !TIME_CHAR(tty) && MIN_CHAR(tty) ? MIN_CHAR(tty) : 1; - return 0; + if (ldata->icanon && !L_EXTPROC(tty)) + return ldata->canon_head != ldata->read_tail; + else + return read_cnt(ldata) >= amt; } /** - * copy_from_read_buf - copy read data directly + * copy_from_read_buf - copy read data directly * @tty: terminal device * @b: user data * @nr: size of data @@ -1613,8 +1920,11 @@ static inline int input_available_p(struct tty_struct *tty, int amt) * buffer, and once to drain the space from the (physical) beginning of * the buffer to head pointer. * - * Called under the tty->atomic_read_lock sem + * Called under the ldata->atomic_read_lock sem * + * n_tty_read()/consumer path: + * caller holds non-exclusive termios_rwsem + * read_tail published */ static int copy_from_read_buf(struct tty_struct *tty, @@ -1622,34 +1932,129 @@ static int copy_from_read_buf(struct tty_struct *tty, size_t *nr) { + struct n_tty_data *ldata = tty->disc_data; int retval; size_t n; - unsigned long flags; + bool is_eof; + size_t tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); retval = 0; - spin_lock_irqsave(&tty->read_lock, flags); - n = min(tty->read_cnt, N_TTY_BUF_SIZE - tty->read_tail); + n = min(read_cnt(ldata), N_TTY_BUF_SIZE - tail); n = min(*nr, n); - spin_unlock_irqrestore(&tty->read_lock, flags); if (n) { - retval = copy_to_user(*b, &tty->read_buf[tty->read_tail], n); + retval = copy_to_user(*b, read_buf_addr(ldata, tail), n); n -= retval; - tty_audit_add_data(tty, &tty->read_buf[tty->read_tail], n); - spin_lock_irqsave(&tty->read_lock, flags); - tty->read_tail = (tty->read_tail + n) & (N_TTY_BUF_SIZE-1); - tty->read_cnt -= n; + is_eof = n == 1 && read_buf(ldata, tail) == EOF_CHAR(tty); + tty_audit_add_data(tty, read_buf_addr(ldata, tail), n, + ldata->icanon); + ldata->read_tail += n; /* Turn single EOF into zero-length read */ - if (L_EXTPROC(tty) && tty->icanon && n == 1) { - if (!tty->read_cnt && (*b)[n-1] == EOF_CHAR(tty)) - n--; - } - spin_unlock_irqrestore(&tty->read_lock, flags); + if (L_EXTPROC(tty) && ldata->icanon && is_eof && !read_cnt(ldata)) + n = 0; *b += n; *nr -= n; } return retval; } +/** + * canon_copy_from_read_buf - copy read data in canonical mode + * @tty: terminal device + * @b: user data + * @nr: size of data + * + * Helper function for n_tty_read. It is only called when ICANON is on; + * it copies one line of input up to and including the line-delimiting + * character into the user-space buffer. + * + * NB: When termios is changed from non-canonical to canonical mode and + * the read buffer contains data, n_tty_set_termios() simulates an EOF + * push (as if C-d were input) _without_ the DISABLED_CHAR in the buffer. + * This causes data already processed as input to be immediately available + * as input although a newline has not been received. + * + * Called under the atomic_read_lock mutex + * + * n_tty_read()/consumer path: + * caller holds non-exclusive termios_rwsem + * read_tail published + */ + +static int canon_copy_from_read_buf(struct tty_struct *tty, + unsigned char __user **b, + size_t *nr) +{ + struct n_tty_data *ldata = tty->disc_data; + size_t n, size, more, c; + size_t eol; + size_t tail; + int ret, found = 0; + bool eof_push = 0; + + /* N.B. avoid overrun if nr == 0 */ + n = min(*nr, read_cnt(ldata)); + if (!n) + return 0; + + tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); + size = min_t(size_t, tail + n, N_TTY_BUF_SIZE); + + n_tty_trace("%s: nr:%zu tail:%zu n:%zu size:%zu\n", + __func__, *nr, tail, n, size); + + eol = find_next_bit(ldata->read_flags, size, tail); + more = n - (size - tail); + if (eol == N_TTY_BUF_SIZE && more) { + /* scan wrapped without finding set bit */ + eol = find_next_bit(ldata->read_flags, more, 0); + if (eol != more) + found = 1; + } else if (eol != size) + found = 1; + + size = N_TTY_BUF_SIZE - tail; + n = eol - tail; + if (n > 4096) + n += 4096; + n += found; + c = n; + + if (found && !ldata->push && read_buf(ldata, eol) == __DISABLED_CHAR) { + n--; + eof_push = !n && ldata->read_tail != ldata->line_start; + } + + n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu size:%zu more:%zu\n", + __func__, eol, found, n, c, size, more); + + if (n > size) { + ret = copy_to_user(*b, read_buf_addr(ldata, tail), size); + if (ret) + return -EFAULT; + ret = copy_to_user(*b + size, ldata->read_buf, n - size); + } else + ret = copy_to_user(*b, read_buf_addr(ldata, tail), n); + + if (ret) + return -EFAULT; + *b += n; + *nr -= n; + + if (found) + clear_bit(eol, ldata->read_flags); + smp_mb__after_atomic(); + ldata->read_tail += c; + + if (found) { + if (!ldata->push) + ldata->line_start = ldata->read_tail; + else + ldata->push = 0; + tty_audit_push(tty); + } + return eof_push ? -EAGAIN : 0; +} + extern ssize_t redirected_tty_write(struct file *, const char __user *, size_t, loff_t *); @@ -1662,10 +2067,9 @@ extern ssize_t redirected_tty_write(struct file *, const char __user *, * and if appropriate send any needed signals and return a negative * error code if action should be taken. * - * FIXME: - * Locking: None - redirected write test is safe, testing - * current->signal should possibly lock current->sighand - * pgrp locking ? + * Locking: redirected write test is safe + * current->signal->tty check is safe + * ctrl_lock to safely reference tty->pgrp */ static int job_control(struct tty_struct *tty, struct file *file) @@ -1675,19 +2079,22 @@ static int job_control(struct tty_struct *tty, struct file *file) /* NOTE: not yet done after every sleep pending a thorough check of the logic of this change. -- jlc */ /* don't stop on /dev/console */ - if (file->f_op->write != redirected_tty_write && - current->signal->tty == tty) { - if (!tty->pgrp) - 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()) - return -EIO; - kill_pgrp(task_pgrp(current), SIGTTIN, 1); - set_thread_flag(TIF_SIGPENDING); - return -ERESTARTSYS; - } + if (file->f_op->write == redirected_tty_write || + current->signal->tty != tty) + return 0; + + spin_lock_irq(&tty->ctrl_lock); + if (!tty->pgrp) + printk(KERN_ERR "n_tty_read: no tty->pgrp!\n"); + else if (task_pgrp(current) != tty->pgrp) { + spin_unlock_irq(&tty->ctrl_lock); + if (is_ignored(SIGTTIN) || is_current_pgrp_orphaned()) + return -EIO; + kill_pgrp(task_pgrp(current), SIGTTIN, 1); + set_thread_flag(TIF_SIGPENDING); + return -ERESTARTSYS; } + spin_unlock_irq(&tty->ctrl_lock); return 0; } @@ -1705,60 +2112,59 @@ static int job_control(struct tty_struct *tty, struct file *file) * a hangup. Always called in user context, may sleep. * * This code must be sure never to sleep through a hangup. + * + * n_tty_read()/consumer path: + * claims non-exclusive termios_rwsem + * publishes read_tail */ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, unsigned char __user *buf, size_t nr) { + struct n_tty_data *ldata = tty->disc_data; 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; int packet; -do_it_again: - - BUG_ON(!tty->read_buf); - c = job_control(tty, file); if (c < 0) return c; + /* + * Internal serialization of reads. + */ + if (file->f_flags & O_NONBLOCK) { + if (!mutex_trylock(&ldata->atomic_read_lock)) + return -EAGAIN; + } else { + if (mutex_lock_interruptible(&ldata->atomic_read_lock)) + return -ERESTARTSYS; + } + + down_read(&tty->termios_rwsem); + minimum = time = 0; timeout = MAX_SCHEDULE_TIMEOUT; - if (!tty->icanon) { - time = (HZ / 10) * TIME_CHAR(tty); + if (!ldata->icanon) { minimum = MIN_CHAR(tty); if (minimum) { + time = (HZ / 10) * TIME_CHAR(tty); if (time) - tty->minimum_to_wake = 1; + ldata->minimum_to_wake = 1; else if (!waitqueue_active(&tty->read_wait) || - (tty->minimum_to_wake > minimum)) - tty->minimum_to_wake = minimum; + (ldata->minimum_to_wake > minimum)) + ldata->minimum_to_wake = minimum; } else { - timeout = 0; - if (time) { - timeout = time; - time = 0; - } - tty->minimum_to_wake = minimum = 1; + timeout = (HZ / 10) * TIME_CHAR(tty); + ldata->minimum_to_wake = minimum = 1; } } - /* - * Internal serialization of reads. - */ - if (file->f_flags & O_NONBLOCK) { - if (!mutex_trylock(&tty->atomic_read_lock)) - return -EAGAIN; - } else { - if (mutex_lock_interruptible(&tty->atomic_read_lock)) - return -ERESTARTSYS; - } packet = tty->packet; add_wait_queue(&tty->read_wait, &wait); @@ -1785,31 +2191,40 @@ do_it_again: TASK_RUNNING. */ set_current_state(TASK_INTERRUPTIBLE); - if (((minimum - (b - buf)) < tty->minimum_to_wake) && + if (((minimum - (b - buf)) < ldata->minimum_to_wake) && ((minimum - (b - buf)) >= 1)) - tty->minimum_to_wake = (minimum - (b - buf)); + ldata->minimum_to_wake = (minimum - (b - buf)); if (!input_available_p(tty, 0)) { if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { - retval = -EIO; - break; - } - if (tty_hung_up_p(file)) - break; - if (!timeout) - break; - if (file->f_flags & O_NONBLOCK) { - retval = -EAGAIN; - break; - } - if (signal_pending(current)) { - retval = -ERESTARTSYS; - break; + up_read(&tty->termios_rwsem); + tty_flush_to_ldisc(tty); + down_read(&tty->termios_rwsem); + if (!input_available_p(tty, 0)) { + retval = -EIO; + break; + } + } else { + if (tty_hung_up_p(file)) + break; + if (!timeout) + break; + if (file->f_flags & O_NONBLOCK) { + retval = -EAGAIN; + break; + } + if (signal_pending(current)) { + retval = -ERESTARTSYS; + break; + } + n_tty_set_room(tty); + up_read(&tty->termios_rwsem); + + timeout = schedule_timeout(timeout); + + down_read(&tty->termios_rwsem); + continue; } - /* FIXME: does n_tty_set_room need locking ? */ - n_tty_set_room(tty); - timeout = schedule_timeout(timeout); - continue; } __set_current_state(TASK_RUNNING); @@ -1823,42 +2238,12 @@ do_it_again: nr--; } - if (tty->icanon && !L_EXTPROC(tty)) { - /* N.B. avoid overrun if nr == 0 */ - while (nr && tty->read_cnt) { - int eol; - - eol = test_and_clear_bit(tty->read_tail, - tty->read_flags); - c = tty->read_buf[tty->read_tail]; - spin_lock_irqsave(&tty->read_lock, flags); - tty->read_tail = ((tty->read_tail+1) & - (N_TTY_BUF_SIZE-1)); - tty->read_cnt--; - if (eol) { - /* this test should be redundant: - * we shouldn't be reading data if - * canon_data is 0 - */ - if (--tty->canon_data < 0) - tty->canon_data = 0; - } - spin_unlock_irqrestore(&tty->read_lock, flags); - - if (!eol || (c != __DISABLED_CHAR)) { - if (tty_put_user(tty, c, b++)) { - retval = -EFAULT; - b--; - break; - } - nr--; - } - if (eol) { - tty_audit_push(tty); - break; - } - } - if (retval) + if (ldata->icanon && !L_EXTPROC(tty)) { + retval = canon_copy_from_read_buf(tty, &b, &nr); + if (retval == -EAGAIN) { + retval = 0; + continue; + } else if (retval) break; } else { int uncopied; @@ -1872,39 +2257,26 @@ do_it_again: } } - /* If there is enough space in the read buffer now, let the - * low-level driver know. We use n_tty_chars_in_buffer() to - * check the buffer, as it now knows about canonical mode. - * Otherwise, if the driver is throttled and the line is - * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, - * we won't get any more characters. - */ - if (n_tty_chars_in_buffer(tty) <= TTY_THRESHOLD_UNTHROTTLE) { - n_tty_set_room(tty); - check_unthrottle(tty); - } + n_tty_check_unthrottle(tty); if (b - buf >= minimum) break; if (time) timeout = time; } - mutex_unlock(&tty->atomic_read_lock); - remove_wait_queue(&tty->read_wait, &wait); + n_tty_set_room(tty); + up_read(&tty->termios_rwsem); + remove_wait_queue(&tty->read_wait, &wait); if (!waitqueue_active(&tty->read_wait)) - tty->minimum_to_wake = minimum; + ldata->minimum_to_wake = minimum; + + mutex_unlock(&ldata->atomic_read_lock); __set_current_state(TASK_RUNNING); - size = b - buf; - if (size) { - retval = size; - if (nr) - clear_bit(TTY_PUSH, &tty->flags); - } else if (test_and_clear_bit(TTY_PUSH, &tty->flags)) - goto do_it_again; + if (b - buf) + retval = b - buf; - n_tty_set_room(tty); return retval; } @@ -1945,6 +2317,8 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, return retval; } + down_read(&tty->termios_rwsem); + /* Write out any echoed characters that are still pending */ process_echoes(tty); @@ -1959,7 +2333,7 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, retval = -EIO; break; } - if (O_OPOST(tty) && !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) { + if (O_OPOST(tty)) { while (nr > 0) { ssize_t num = process_output_block(tty, b, nr); if (num < 0) { @@ -1980,8 +2354,12 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, if (tty->ops->flush_chars) tty->ops->flush_chars(tty); } else { + struct n_tty_data *ldata = tty->disc_data; + while (nr > 0) { + mutex_lock(&ldata->output_lock); c = tty->ops->write(tty, b, nr); + mutex_unlock(&ldata->output_lock); if (c < 0) { retval = c; goto break_out; @@ -1998,13 +2376,18 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, retval = -EAGAIN; break; } + up_read(&tty->termios_rwsem); + schedule(); + + down_read(&tty->termios_rwsem); } break_out: __set_current_state(TASK_RUNNING); remove_wait_queue(&tty->write_wait, &wait); if (b - buf != nr && tty->fasync) set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); + up_read(&tty->termios_rwsem); return (b - buf) ? b - buf : retval; } @@ -2025,11 +2408,12 @@ break_out: static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, poll_table *wait) { + struct n_tty_data *ldata = tty->disc_data; unsigned int mask = 0; poll_wait(file, &tty->read_wait, wait); poll_wait(file, &tty->write_wait, wait); - if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty))) + if (input_available_p(tty, 1)) mask |= POLLIN | POLLRDNORM; if (tty->packet && tty->link->ctrl_status) mask |= POLLPRI | POLLIN | POLLRDNORM; @@ -2039,9 +2423,9 @@ static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, mask |= POLLHUP; if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { if (MIN_CHAR(tty) && !TIME_CHAR(tty)) - tty->minimum_to_wake = MIN_CHAR(tty); + ldata->minimum_to_wake = MIN_CHAR(tty); else - tty->minimum_to_wake = 1; + ldata->minimum_to_wake = 1; } if (tty->ops->write && !tty_is_writelocked(tty) && tty_chars_in_buffer(tty) < WAKEUP_CHARS && @@ -2050,21 +2434,21 @@ static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, return mask; } -static unsigned long inq_canon(struct tty_struct *tty) +static unsigned long inq_canon(struct n_tty_data *ldata) { - int nr, head, tail; + size_t nr, head, tail; - if (!tty->canon_data) + if (ldata->canon_head == ldata->read_tail) return 0; - head = tty->canon_head; - tail = tty->read_tail; - nr = (head - tail) & (N_TTY_BUF_SIZE-1); + head = ldata->canon_head; + tail = ldata->read_tail; + nr = head - tail; /* Skip EOF-chars.. */ while (head != tail) { - if (test_bit(tail, tty->read_flags) && - tty->read_buf[tail] == __DISABLED_CHAR) + if (test_bit(tail & (N_TTY_BUF_SIZE - 1), ldata->read_flags) && + read_buf(ldata, tail) == __DISABLED_CHAR) nr--; - tail = (tail+1) & (N_TTY_BUF_SIZE-1); + tail++; } return nr; } @@ -2072,22 +2456,37 @@ static unsigned long inq_canon(struct tty_struct *tty) static int n_tty_ioctl(struct tty_struct *tty, struct file *file, unsigned int cmd, unsigned long arg) { + struct n_tty_data *ldata = tty->disc_data; 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; + down_write(&tty->termios_rwsem); if (L_ICANON(tty)) - retval = inq_canon(tty); + retval = inq_canon(ldata); + else + retval = read_cnt(ldata); + up_write(&tty->termios_rwsem); return put_user(retval, (unsigned int __user *) arg); default: return n_tty_ioctl_helper(tty, file, cmd, arg); } } +static void n_tty_fasync(struct tty_struct *tty, int on) +{ + struct n_tty_data *ldata = tty->disc_data; + + if (!waitqueue_active(&tty->read_wait)) { + if (on) + ldata->minimum_to_wake = 1; + else if (!tty->fasync) + ldata->minimum_to_wake = N_TTY_BUF_SIZE; + } +} + struct tty_ldisc_ops tty_ldisc_N_TTY = { .magic = TTY_LDISC_MAGIC, .name = "n_tty", @@ -2101,14 +2500,16 @@ struct tty_ldisc_ops tty_ldisc_N_TTY = { .set_termios = n_tty_set_termios, .poll = n_tty_poll, .receive_buf = n_tty_receive_buf, - .write_wakeup = n_tty_write_wakeup + .write_wakeup = n_tty_write_wakeup, + .fasync = n_tty_fasync, + .receive_buf2 = n_tty_receive_buf2, }; /** * n_tty_inherit_ops - inherit N_TTY methods * @ops: struct tty_ldisc_ops where to save N_TTY methods * - * Used by a generic struct tty_ldisc_ops to easily inherit N_TTY + * Enables a 'subclass' line discipline to 'inherit' N_TTY * methods. */ |