/*
* n_tty.c --- implements the N_TTY line discipline.
- *
+ *
* This code used to be in tty_io.c, but things are getting hairy
* enough that it made sense to split things off. (The N_TTY
* processing has changed so much that it's hardly recognizable,
*
* Note that the open routine for N_TTY is guaranteed never to return
* an error. This is because Linux will fall back to setting a line
- * to N_TTY if it can not switch to any other line discipline.
+ * to N_TTY if it can not switch to any other line discipline.
*
* Written by Theodore Ts'o, Copyright 1994.
- *
+ *
* This file also contains code originally written by Linus Torvalds,
* Copyright 1991, 1992, 1993, and by Julian Cowley, Copyright 1994.
- *
+ *
* This file may be redistributed under the terms of the GNU General Public
* License.
*
* Reduced memory usage for older ARM systems - Russell King.
*
- * 2000/01/20 Fixed SMP locking on put_tty_queue using bits of
+ * 2000/01/20 Fixed SMP locking on put_tty_queue using bits of
* the patch by Andrew J. Kroll <ag784@freenet.buffalo.edu>
* who actually finally proved there really was a race.
*
* 2002/03/18 Implemented n_tty_wakeup to send SIGIO POLL_OUTs to
* waiting writing processes-Sapan Bhatia <sapan@corewars.org>.
- * Also fixed a bug in BLOCKING mode where write_chan returns
+ * Also fixed a bug in BLOCKING mode where n_tty_write returns
* EAGAIN
*/
#include <linux/slab.h>
#include <linux/poll.h>
#include <linux/bitops.h>
+#include <linux/audit.h>
+#include <linux/file.h>
+#include <linux/uaccess.h>
+#include <linux/module.h>
-#include <asm/uaccess.h>
#include <asm/system.h>
/* number of characters left in xmit buffer before select has we have room */
#define TTY_THRESHOLD_THROTTLE 128 /* now based on remaining room */
#define TTY_THRESHOLD_UNTHROTTLE 128
-static inline unsigned char *alloc_buf(void)
-{
- unsigned int prio = in_interrupt() ? GFP_ATOMIC : GFP_KERNEL;
+/*
+ * Special byte codes used in the echo buffer to represent operations
+ * or special handling of characters. Bytes in the echo buffer that
+ * are not part of such special blocks are treated as normal character
+ * codes.
+ */
+#define ECHO_OP_START 0xff
+#define ECHO_OP_MOVE_BACK_COL 0x80
+#define ECHO_OP_SET_CANON_COL 0x81
+#define ECHO_OP_ERASE_TAB 0x82
- if (PAGE_SIZE != N_TTY_BUF_SIZE)
- return kmalloc(N_TTY_BUF_SIZE, prio);
- else
- return (unsigned char *)__get_free_page(prio);
+static inline int tty_put_user(struct tty_struct *tty, unsigned char x,
+ unsigned char __user *ptr)
+{
+ tty_audit_add_data(tty, &x, 1);
+ return put_user(x, ptr);
}
-static inline void free_buf(unsigned char *buf)
+/**
+ * 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)
{
- if (PAGE_SIZE != N_TTY_BUF_SIZE)
- kfree(buf);
- else
- free_page((unsigned long) buf);
+ /* tty->read_cnt is not read locked ? */
+ int left = N_TTY_BUF_SIZE - tty->read_cnt - 1;
+
+ /*
+ * If we are doing input canonicalization, and there are no
+ * pending newlines, let characters through without limit, so
+ * that erase characters will be handled. Other excess
+ * characters will be beeped.
+ */
+ if (left <= 0)
+ left = tty->icanon && !tty->canon_data;
+ tty->receive_room = left;
}
-static inline void put_tty_queue_nolock(unsigned char c, struct tty_struct *tty)
+static void put_tty_queue_nolock(unsigned char c, struct tty_struct *tty)
{
if (tty->read_cnt < N_TTY_BUF_SIZE) {
tty->read_buf[tty->read_head] = c;
}
}
-static inline void put_tty_queue(unsigned char c, struct tty_struct *tty)
+/**
+ * put_tty_queue - add character to tty
+ * @c: character
+ * @tty: tty device
+ *
+ * Add a character to the tty read_buf queue. This is done under the
+ * read_lock to serialize character addition and also to protect us
+ * against parallel reads or flushes
+ */
+
+static void put_tty_queue(unsigned char c, struct tty_struct *tty)
{
unsigned long flags;
/*
* check_unthrottle - allow new receive data
* @tty; tty device
*
- * Check whether to call the driver.unthrottle function.
- * We test the TTY_THROTTLED bit first so that it always
- * indicates the current state. The decision about whether
- * it is worth allowing more input has been taken by the caller.
- * Can sleep, may be called under the atomic_read semaphore but
+ * Check whether to call the driver unthrottle functions
+ *
+ * Can sleep, may be called under the atomic_read_lock mutex but
* this is not guaranteed.
*/
-
-static void check_unthrottle(struct tty_struct * tty)
+static void check_unthrottle(struct tty_struct *tty)
{
- if (tty->count &&
- test_and_clear_bit(TTY_THROTTLED, &tty->flags) &&
- tty->driver->unthrottle)
- tty->driver->unthrottle(tty);
+ if (tty->count)
+ tty_unthrottle(tty);
}
/**
* reset_buffer_flags - reset buffer state
* @tty: terminal to reset
*
- * Reset the read buffer counters, clear the flags,
+ * Reset the read buffer counters, clear the flags,
* and make sure the driver is unthrottled. Called
* from n_tty_open() and n_tty_flush_buffer().
+ *
+ * Locking: tty_read_lock for read fields.
*/
+
static void reset_buffer_flags(struct tty_struct *tty)
{
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);
+
+ mutex_lock(&tty->echo_lock);
+ tty->echo_pos = tty->echo_cnt = tty->echo_overrun = 0;
+ mutex_unlock(&tty->echo_lock);
+
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);
}
* 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.
+ * Locking: ctrl_lock, read_lock.
*/
-
-static void n_tty_flush_buffer(struct tty_struct * tty)
+
+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;
+ 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);
}
/**
* @tty: tty device
*
* Report the number of characters buffered to be delivered to user
- * at this instant in time.
+ * at this instant in time.
+ *
+ * Locking: read_lock
*/
-
+
static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty)
{
unsigned long flags;
* 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;
* 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);
}
/**
- * opost - output post processor
+ * do_output_char - output one character
* @c: character (or partial unicode symbol)
* @tty: terminal device
+ * @space: space available in tty driver write buffer
*
- * 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.
+ * This is a helper function that handles one output character
+ * (including special characters like TAB, CR, LF, etc.),
+ * doing OPOST processing and putting the results in the
+ * tty driver's write buffer.
*
- * Called from both the receive and transmit sides and can be called
- * re-entrantly. Relies on lock_kernel() still.
+ * 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.
+ *
+ * Returns the number of bytes of buffer space used or -1 if
+ * no space left.
+ *
+ * Locking: should be called under the output_lock to protect
+ * the column state and space left in the buffer
*/
-
-static int opost(unsigned char c, struct tty_struct *tty)
+
+static int do_output_char(unsigned char c, struct tty_struct *tty, int space)
{
- int space, spaces;
+ int spaces;
- space = tty->driver->write_room(tty);
if (!space)
return -1;
- if (O_OPOST(tty)) {
- switch (c) {
- case '\n':
- if (O_ONLRET(tty))
- tty->column = 0;
- if (O_ONLCR(tty)) {
- if (space < 2)
- return -1;
- tty->driver->put_char(tty, '\r');
- tty->column = 0;
- }
- tty->canon_column = tty->column;
- break;
- case '\r':
- if (O_ONOCR(tty) && tty->column == 0)
- return 0;
- if (O_OCRNL(tty)) {
- c = '\n';
- if (O_ONLRET(tty))
- tty->canon_column = tty->column = 0;
- break;
- }
+ switch (c) {
+ case '\n':
+ if (O_ONLRET(tty))
+ tty->column = 0;
+ if (O_ONLCR(tty)) {
+ if (space < 2)
+ return -1;
tty->canon_column = tty->column = 0;
+ tty->ops->write(tty, "\r\n", 2);
+ return 2;
+ }
+ tty->canon_column = tty->column;
+ break;
+ case '\r':
+ if (O_ONOCR(tty) && tty->column == 0)
+ return 0;
+ if (O_OCRNL(tty)) {
+ c = '\n';
+ if (O_ONLRET(tty))
+ tty->canon_column = tty->column = 0;
break;
- case '\t':
- spaces = 8 - (tty->column & 7);
- if (O_TABDLY(tty) == XTABS) {
- if (space < spaces)
- return -1;
- tty->column += spaces;
- tty->driver->write(tty, " ", spaces);
- return 0;
- }
+ }
+ tty->canon_column = tty->column = 0;
+ break;
+ case '\t':
+ spaces = 8 - (tty->column & 7);
+ if (O_TABDLY(tty) == XTABS) {
+ if (space < spaces)
+ return -1;
tty->column += spaces;
- break;
- case '\b':
- if (tty->column > 0)
- tty->column--;
- break;
- default:
+ tty->ops->write(tty, " ", spaces);
+ return spaces;
+ }
+ tty->column += spaces;
+ break;
+ case '\b':
+ if (tty->column > 0)
+ tty->column--;
+ break;
+ default:
+ if (!iscntrl(c)) {
if (O_OLCUC(tty))
c = toupper(c);
- if (!iscntrl(c) && !is_continuation(c, tty))
+ if (!is_continuation(c, tty))
tty->column++;
- break;
}
+ break;
}
- tty->driver->put_char(tty, c);
- return 0;
+
+ tty_put_char(tty, c);
+ return 1;
+}
+
+/**
+ * process_output - output post processor
+ * @c: character (or partial unicode symbol)
+ * @tty: terminal device
+ *
+ * Output one character with OPOST processing.
+ * Returns -1 when the output device is full and the character
+ * must be retried.
+ *
+ * Locking: output_lock to protect column state and space left
+ * (also, this is called from n_tty_write under the
+ * tty layer write lock)
+ */
+
+static int process_output(unsigned char c, struct tty_struct *tty)
+{
+ int space, retval;
+
+ mutex_lock(&tty->output_lock);
+
+ space = tty_write_room(tty);
+ retval = do_output_char(c, tty, space);
+
+ mutex_unlock(&tty->output_lock);
+ if (retval < 0)
+ return -1;
+ else
+ return 0;
}
/**
- * opost_block - block postprocess
+ * process_output_block - block post processor
* @tty: terminal device
- * @inbuf: user buffer
- * @nr: number of bytes
+ * @buf: character buffer
+ * @nr: number of bytes to output
+ *
+ * Output a block of characters with OPOST processing.
+ * Returns the number of characters output.
*
* 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.
+ * Locking: output_lock to protect column state and space left
+ * (also, this is called from n_tty_write under the
+ * tty layer write lock)
*/
-
-static ssize_t opost_block(struct tty_struct * tty,
- const unsigned char * buf, unsigned int nr)
+
+static ssize_t process_output_block(struct tty_struct *tty,
+ const unsigned char *buf, unsigned int nr)
{
int space;
int i;
const unsigned char *cp;
- space = tty->driver->write_room(tty);
- if (!space)
+ mutex_lock(&tty->output_lock);
+
+ space = tty_write_room(tty);
+ if (!space) {
+ mutex_unlock(&tty->output_lock);
return 0;
+ }
if (nr > space)
nr = space;
for (i = 0, cp = buf; i < nr; i++, cp++) {
- switch (*cp) {
+ unsigned char c = *cp;
+
+ switch (c) {
case '\n':
if (O_ONLRET(tty))
tty->column = 0;
tty->column--;
break;
default:
- if (O_OLCUC(tty))
- goto break_out;
- if (!iscntrl(*cp))
- tty->column++;
+ if (!iscntrl(c)) {
+ if (O_OLCUC(tty))
+ goto break_out;
+ if (!is_continuation(c, tty))
+ tty->column++;
+ }
break;
}
}
break_out:
- if (tty->driver->flush_chars)
- tty->driver->flush_chars(tty);
- i = tty->driver->write(tty, buf, i);
+ i = tty->ops->write(tty, buf, i);
+
+ mutex_unlock(&tty->output_lock);
return i;
}
+/**
+ * process_echoes - write pending echo characters
+ * @tty: terminal device
+ *
+ * Write previously buffered echo (and other ldisc-generated)
+ * characters to the tty.
+ *
+ * Characters generated by the ldisc (including echoes) need to
+ * be buffered because the driver's write buffer can fill during
+ * heavy program output. Echoing straight to the driver will
+ * often fail under these conditions, causing lost characters and
+ * resulting mismatches of ldisc state information.
+ *
+ * Since the ldisc state must represent the characters actually sent
+ * to the driver at the time of the write, operations like certain
+ * changes in column state are also saved in the buffer and executed
+ * here.
+ *
+ * A circular fifo buffer is used so that the most recent characters
+ * 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
+ */
+
+static void process_echoes(struct tty_struct *tty)
+{
+ int space, nr;
+ 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);
+
+ 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;
+ if (c == ECHO_OP_START) {
+ unsigned char op;
+ unsigned char *opp;
+ int no_space_left = 0;
+
+ /*
+ * If the buffer byte is the start of a multi-byte
+ * 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;
+
+ 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;
+
+ /*
+ * Determine how many columns to go back
+ * in order to erase the tab.
+ * This depends on the number of columns
+ * used by other characters within the tab
+ * area. If this (modulo 8) count is from
+ * the start of input rather than from a
+ * previous tab, we offset by canon column.
+ * Otherwise, tab spacing is normal.
+ */
+ if (!(num_chars & 0x80))
+ num_chars += tty->canon_column;
+ num_bs = 8 - (num_chars & 7);
+
+ if (num_bs > space) {
+ no_space_left = 1;
+ break;
+ }
+ space -= num_bs;
+ while (num_bs--) {
+ tty_put_char(tty, '\b');
+ if (tty->column > 0)
+ tty->column--;
+ }
+ cp += 3;
+ nr -= 3;
+ break;
+
+ case ECHO_OP_SET_CANON_COL:
+ tty->canon_column = tty->column;
+ cp += 2;
+ nr -= 2;
+ break;
+
+ case ECHO_OP_MOVE_BACK_COL:
+ if (tty->column > 0)
+ tty->column--;
+ cp += 2;
+ nr -= 2;
+ break;
+
+ case ECHO_OP_START:
+ /* This is an escaped echo op start code */
+ if (!space) {
+ no_space_left = 1;
+ break;
+ }
+ tty_put_char(tty, ECHO_OP_START);
+ tty->column++;
+ space--;
+ cp += 2;
+ nr -= 2;
+ break;
+
+ default:
+ /*
+ * If the op is not a special byte code,
+ * it is a ctrl char tagged to be echoed
+ * as "^X" (where X is the letter
+ * representing the control char).
+ * Note that we must ensure there is
+ * enough space for the whole ctrl pair.
+ *
+ */
+ if (space < 2) {
+ no_space_left = 1;
+ break;
+ }
+ tty_put_char(tty, '^');
+ tty_put_char(tty, op ^ 0100);
+ tty->column += 2;
+ space -= 2;
+ cp += 2;
+ nr -= 2;
+ }
+
+ if (no_space_left)
+ break;
+ } else {
+ if (O_OPOST(tty) &&
+ !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) {
+ int retval = do_output_char(c, tty, space);
+ if (retval < 0)
+ break;
+ space -= retval;
+ } else {
+ if (!space)
+ break;
+ tty_put_char(tty, c);
+ space -= 1;
+ }
+ cp += 1;
+ nr -= 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;
+ }
+
+ mutex_unlock(&tty->echo_lock);
+ mutex_unlock(&tty->output_lock);
+
+ if (tty->ops->flush_chars)
+ tty->ops->flush_chars(tty);
+}
+
+/**
+ * add_echo_byte - add a byte to the echo buffer
+ * @c: unicode byte to echo
+ * @tty: terminal device
+ *
+ * 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)
+{
+ 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_move_back_col - add operation to move back a column
+ * @tty: terminal device
+ *
+ * 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)
+{
+ 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);
+}
+
+/**
+ * echo_set_canon_col - add operation to set the canon column
+ * @tty: terminal device
+ *
+ * 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)
+{
+ 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);
+}
/**
- * put_char - write character to driver
- * @c: character (or part of unicode symbol)
+ * 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
*
- * Queue a byte to the driver layer for output
+ * Add an operation to the echo buffer to erase a tab.
+ *
+ * Called by the eraser function, which knows how many character
+ * columns have been used since either a previous tab or the start
+ * 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 inline void put_char(unsigned char c, struct tty_struct *tty)
+
+static void echo_erase_tab(unsigned int num_chars, int after_tab,
+ struct tty_struct *tty)
{
- tty->driver->put_char(tty, c);
+ mutex_lock(&tty->echo_lock);
+
+ add_echo_byte(ECHO_OP_START, tty);
+ add_echo_byte(ECHO_OP_ERASE_TAB, tty);
+
+ /* We only need to know this modulo 8 (tab spacing) */
+ num_chars &= 7;
+
+ /* Set the high bit as a flag if num_chars is after a previous tab */
+ if (after_tab)
+ num_chars |= 0x80;
+
+ add_echo_byte(num_chars, tty);
+
+ mutex_unlock(&tty->echo_lock);
}
/**
- * echo_char - echo characters
+ * echo_char_raw - echo a character raw
* @c: unicode byte to echo
* @tty: terminal device
*
- * Echo user input back onto the screen. This must be called only when
+ * 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.
+ *
+ * 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)
+{
+ mutex_lock(&tty->echo_lock);
+
+ if (c == ECHO_OP_START) {
+ add_echo_byte(ECHO_OP_START, tty);
+ add_echo_byte(ECHO_OP_START, tty);
+ } else {
+ add_echo_byte(c, tty);
+ }
+
+ mutex_unlock(&tty->echo_lock);
+}
+
+/**
+ * echo_char - echo a character
+ * @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.
+ *
+ * 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)
{
- if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') {
- put_char('^', tty);
- put_char(c ^ 0100, tty);
- tty->column += 2;
- } else
- opost(c, tty);
+ mutex_lock(&tty->echo_lock);
+
+ if (c == ECHO_OP_START) {
+ add_echo_byte(ECHO_OP_START, tty);
+ add_echo_byte(ECHO_OP_START, tty);
+ } else {
+ if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t')
+ add_echo_byte(ECHO_OP_START, tty);
+ add_echo_byte(c, tty);
+ }
+
+ mutex_unlock(&tty->echo_lock);
}
+/**
+ * finish_erasing - complete erase
+ * @tty: tty doing the erase
+ */
+
static inline void finish_erasing(struct tty_struct *tty)
{
if (tty->erasing) {
- put_char('/', tty);
- tty->column++;
+ echo_char_raw('/', tty);
tty->erasing = 0;
}
}
* @c: character input
* @tty: terminal device
*
- * Perform erase and neccessary output when an erase character is
+ * Perform erase and necessary output when an erase character is
* present in the stream from the driver layer. Handles the complexities
* of UTF-8 multibyte symbols.
+ *
+ * Locking: read_lock for tty buffers
*/
-
+
static void eraser(unsigned char c, struct tty_struct *tty)
{
enum { ERASE, WERASE, KILL } kill_type;
int head, seen_alnums, cnt;
unsigned long flags;
+ /* FIXME: locking needed ? */
if (tty->read_head == tty->canon_head) {
- /* opost('\a', tty); */ /* what do you think? */
+ /* process_output('\a', tty); */ /* what do you think? */
return;
}
if (c == ERASE_CHAR(tty))
echo_char(KILL_CHAR(tty), tty);
/* Add a newline if ECHOK is on and ECHOKE is off. */
if (L_ECHOK(tty))
- opost('\n', tty);
+ echo_char_raw('\n', tty);
return;
}
kill_type = KILL;
}
seen_alnums = 0;
+ /* FIXME: Locking ?? */
while (tty->read_head != tty->canon_head) {
head = tty->read_head;
if (L_ECHO(tty)) {
if (L_ECHOPRT(tty)) {
if (!tty->erasing) {
- put_char('\\', tty);
- tty->column++;
+ echo_char_raw('\\', tty);
tty->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);
- put_char(tty->read_buf[head], tty);
+ echo_char_raw(tty->read_buf[head], tty);
+ echo_move_back_col(tty);
}
} else if (kill_type == ERASE && !L_ECHOE(tty)) {
echo_char(ERASE_CHAR(tty), tty);
} else if (c == '\t') {
- unsigned int col = tty->canon_column;
- unsigned long tail = tty->canon_head;
-
- /* Find the column of the last char. */
- while (tail != tty->read_head) {
+ unsigned int num_chars = 0;
+ int after_tab = 0;
+ unsigned long tail = tty->read_head;
+
+ /*
+ * Count the columns used for characters
+ * since the start of input or after a
+ * previous tab.
+ * 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];
- if (c == '\t')
- col = (col | 7) + 1;
- else if (iscntrl(c)) {
+ if (c == '\t') {
+ after_tab = 1;
+ break;
+ } else if (iscntrl(c)) {
if (L_ECHOCTL(tty))
- col += 2;
- } else if (!is_continuation(c, tty))
- col++;
- tail = (tail+1) & (N_TTY_BUF_SIZE-1);
- }
-
- /* should never happen */
- if (tty->column > 0x80000000)
- tty->column = 0;
-
- /* Now backup to that column. */
- while (tty->column > col) {
- /* Can't use opost here. */
- put_char('\b', tty);
- if (tty->column > 0)
- tty->column--;
+ num_chars += 2;
+ } else if (!is_continuation(c, tty)) {
+ num_chars++;
+ }
}
+ echo_erase_tab(num_chars, after_tab, tty);
} else {
if (iscntrl(c) && L_ECHOCTL(tty)) {
- put_char('\b', tty);
- put_char(' ', tty);
- put_char('\b', tty);
- if (tty->column > 0)
- tty->column--;
+ echo_char_raw('\b', tty);
+ echo_char_raw(' ', tty);
+ echo_char_raw('\b', tty);
}
if (!iscntrl(c) || L_ECHOCTL(tty)) {
- put_char('\b', tty);
- put_char(' ', tty);
- put_char('\b', tty);
- if (tty->column > 0)
- tty->column--;
+ echo_char_raw('\b', tty);
+ echo_char_raw(' ', tty);
+ echo_char_raw('\b', tty);
}
}
}
if (kill_type == ERASE)
break;
}
- if (tty->read_head == tty->canon_head)
+ if (tty->read_head == tty->canon_head && L_ECHO(tty))
finish_erasing(tty);
}
* may caus terminal flushing to take place according to the termios
* settings and character used. Called from the driver receive_buf
* path so serialized.
+ *
+ * Locking: ctrl_lock, read_lock (both via flush buffer)
*/
-
+
static inline void isig(int sig, struct tty_struct *tty, int flush)
{
- if (tty->pgrp > 0)
- kill_pg(tty->pgrp, sig, 1);
+ if (tty->pgrp)
+ kill_pgrp(tty->pgrp, sig, 1);
if (flush || !L_NOFLSH(tty)) {
n_tty_flush_buffer(tty);
- if (tty->driver->flush_buffer)
- tty->driver->flush_buffer(tty);
+ tty_driver_flush_buffer(tty);
}
}
*
* Called from the receive_buf path so single threaded.
*/
-
+
static inline void n_tty_receive_break(struct tty_struct *tty)
{
if (I_IGNBRK(tty))
* 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];
* @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.
+ * the error case if necessary. Locking as per n_tty_receive_buf.
*/
static inline void n_tty_receive_parity_error(struct tty_struct *tty,
unsigned char c)
{
- if (I_IGNPAR(tty)) {
+ if (I_IGNPAR(tty))
return;
- }
if (I_PARMRK(tty)) {
put_tty_queue('\377', tty);
put_tty_queue('\0', tty);
* @c: character
*
* Process an individual character of input received from the driver.
- * This is serialized with respect to itself by the rules for the
+ * 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;
+ int parmrk;
if (tty->raw) {
put_tty_queue(c, tty);
return;
}
-
- if (tty->stopped && !tty->flow_stopped &&
- I_IXON(tty) && I_IXANY(tty)) {
- start_tty(tty);
- return;
- }
-
+
if (I_ISTRIP(tty))
c &= 0x7f;
if (I_IUCLC(tty) && L_IEXTEN(tty))
- c=tolower(c);
+ c = tolower(c);
+
+ 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))
+ if (c == START_CHAR(tty)) {
start_tty(tty);
- else if (c == STOP_CHAR(tty))
+ process_echoes(tty);
+ } else if (c == STOP_CHAR(tty))
stop_tty(tty);
}
return;
* up.
*/
if (!test_bit(c, tty->process_char_map) || tty->lnext) {
- finish_erasing(tty);
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)) {
- if (tty->read_cnt >= N_TTY_BUF_SIZE-1) {
- put_char('\a', tty); /* beep if no space */
- return;
- }
+ finish_erasing(tty);
/* Record the column of first canon char. */
if (tty->canon_head == tty->read_head)
- tty->canon_column = tty->column;
+ echo_set_canon_col(tty);
echo_char(c, tty);
+ process_echoes(tty);
}
- if (I_PARMRK(tty) && c == (unsigned char) '\377')
+ if (parmrk)
put_tty_queue(c, tty);
put_tty_queue(c, tty);
return;
}
-
- if (c == '\r') {
- if (I_IGNCR(tty))
- return;
- if (I_ICRNL(tty))
- c = '\n';
- } else if (c == '\n' && I_INLCR(tty))
- c = '\r';
+
if (I_IXON(tty)) {
if (c == START_CHAR(tty)) {
start_tty(tty);
+ process_echoes(tty);
return;
}
if (c == STOP_CHAR(tty)) {
return;
}
}
+
if (L_ISIG(tty)) {
int signal;
signal = SIGINT;
signal = SIGTSTP;
if (c == SUSP_CHAR(tty)) {
send_signal:
- isig(signal, tty, 0);
+ /*
+ * 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 == '\r') {
+ if (I_IGNCR(tty))
+ return;
+ if (I_ICRNL(tty))
+ c = '\n';
+ } else if (c == '\n' && I_INLCR(tty))
+ c = '\r';
+
if (tty->icanon) {
if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) ||
(c == WERASE_CHAR(tty) && L_IEXTEN(tty))) {
eraser(c, tty);
+ process_echoes(tty);
return;
}
if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) {
if (L_ECHO(tty)) {
finish_erasing(tty);
if (L_ECHOCTL(tty)) {
- put_char('^', tty);
- put_char('\b', tty);
+ echo_char_raw('^', tty);
+ echo_char_raw('\b', tty);
+ process_echoes(tty);
}
}
return;
finish_erasing(tty);
echo_char(c, tty);
- opost('\n', 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);
}
+ process_echoes(tty);
return;
}
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)) {
- if (tty->read_cnt >= N_TTY_BUF_SIZE-1)
- put_char('\a', tty);
- opost('\n', tty);
+ echo_char_raw('\n', tty);
+ process_echoes(tty);
}
goto handle_newline;
}
if (c == EOF_CHAR(tty)) {
- if (tty->canon_head != tty->read_head)
- set_bit(TTY_PUSH, &tty->flags);
+ 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)) {
- if (tty->read_cnt >= N_TTY_BUF_SIZE-1)
- put_char('\a', tty);
/* Record the column of first canon char. */
if (tty->canon_head == tty->read_head)
- tty->canon_column = tty->column;
+ echo_set_canon_col(tty);
echo_char(c, tty);
+ process_echoes(tty);
}
/*
* XXX does PARMRK doubling happen for
* EOL_CHAR and EOL2_CHAR?
*/
- if (I_PARMRK(tty) && c == (unsigned char) '\377')
+ if (parmrk)
put_tty_queue(c, tty);
- handle_newline:
+handle_newline:
spin_lock_irqsave(&tty->read_lock, flags);
set_bit(tty->read_head, tty->read_flags);
put_tty_queue_nolock(c, tty);
return;
}
}
-
- finish_erasing(tty);
+
+ 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)) {
- if (tty->read_cnt >= N_TTY_BUF_SIZE-1) {
- put_char('\a', tty); /* beep if no space */
- return;
- }
+ finish_erasing(tty);
if (c == '\n')
- opost('\n', tty);
+ echo_char_raw('\n', tty);
else {
/* Record the column of first canon char. */
if (tty->canon_head == tty->read_head)
- tty->canon_column = tty->column;
+ echo_set_canon_col(tty);
echo_char(c, tty);
}
+ process_echoes(tty);
}
- if (I_PARMRK(tty) && c == (unsigned char) '\377')
+ if (parmrk)
put_tty_queue(c, tty);
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;
-
- /*
- * If we are doing input canonicalization, and there are no
- * pending newlines, let characters through without limit, so
- * that erase characters will be handled. Other excess
- * characters will be beeped.
- */
- if (left <= 0)
- left = tty->icanon && !tty->canon_data;
- return left;
}
+
/**
* n_tty_write_wakeup - asynchronous I/O notifier
* @tty: tty device
static void n_tty_write_wakeup(struct tty_struct *tty)
{
- if (tty->fasync)
- {
- set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
+ if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags))
kill_fasync(&tty->fasync, SIGIO, POLL_OUT);
- }
- return;
}
/**
* 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)
{
tty->read_cnt += i;
spin_unlock_irqrestore(&tty->read_lock, cpuflags);
} else {
- for (i=count, p = cp, f = fp; i; i--, p++) {
+ for (i = count, p = cp, f = fp; i; i--, p++) {
if (f)
flags = *f++;
switch (flags) {
n_tty_receive_overrun(tty);
break;
default:
- printk("%s: unknown flag %d\n",
+ printk(KERN_ERR "%s: unknown flag %d\n",
tty_name(tty, buf), flags);
break;
}
}
- if (tty->driver->flush_chars)
- tty->driver->flush_chars(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)) {
kill_fasync(&tty->fasync, SIGIO, POLL_IN);
if (waitqueue_active(&tty->read_wait))
* mode. We don't want to throttle the driver if we're in
* canonical mode and don't have a newline yet!
*/
- if (n_tty_receive_room(tty) < TTY_THRESHOLD_THROTTLE) {
- /* check TTY_THROTTLED first so it indicates our state */
- if (!test_and_set_bit(TTY_THROTTLED, &tty->flags) &&
- tty->driver->throttle)
- tty->driver->throttle(tty);
- }
+ if (tty->receive_room < TTY_THRESHOLD_THROTTLE)
+ tty_throttle(tty);
}
int is_ignored(int sig)
{
return (sigismember(¤t->blocked, sig) ||
- current->sighand->action[sig-1].sa.sa_handler == SIG_IGN);
+ current->sighand->action[sig-1].sa.sa_handler == SIG_IGN);
}
/**
*
* 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
+ * and is protected from re-entry by the tty layer. The user is
* guaranteed that this function will not be re-entered or in progress
* when the ldisc is closed.
+ *
+ * Locking: Caller holds tty->termios_mutex
*/
-
-static void n_tty_set_termios(struct tty_struct *tty, struct termios * old)
+
+static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
{
- if (!tty)
- return;
-
+ int canon_change = 1;
+ BUG_ON(!tty);
+
+ if (old)
+ canon_change = (old->c_lflag ^ tty->termios->c_lflag) & ICANON;
+ if (canon_change) {
+ memset(&tty->read_flags, 0, sizeof tty->read_flags);
+ tty->canon_head = tty->read_tail;
+ tty->canon_data = 0;
+ tty->erasing = 0;
+ }
+
+ if (canon_change && !L_ICANON(tty) && tty->read_cnt)
+ wake_up_interruptible(&tty->read_wait);
+
tty->icanon = (L_ICANON(tty) != 0);
if (test_bit(TTY_HW_COOK_IN, &tty->flags)) {
tty->raw = 1;
tty->real_raw = 1;
+ n_tty_set_room(tty);
return;
}
if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) ||
else
tty->real_raw = 0;
}
+ n_tty_set_room(tty);
+ /* The termios change make the tty ready for I/O */
+ wake_up_interruptible(&tty->write_wait);
+ wake_up_interruptible(&tty->read_wait);
}
/**
* 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
+ * 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);
if (tty->read_buf) {
- free_buf(tty->read_buf);
+ kfree(tty->read_buf);
tty->read_buf = NULL;
}
+ if (tty->echo_buf) {
+ kfree(tty->echo_buf);
+ tty->echo_buf = NULL;
+ }
}
/**
* n_tty_open - open an ldisc
* @tty: terminal to open
*
- * Called when this line discipline is being attached to the
+ * 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.
if (!tty)
return -EINVAL;
- /* This one is ugly. Currently a malloc failure here can panic */
+ /* These are ugly. Currently a malloc failure here can panic */
if (!tty->read_buf) {
- tty->read_buf = alloc_buf();
+ tty->read_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL);
if (!tty->read_buf)
return -ENOMEM;
}
- memset(tty->read_buf, 0, N_TTY_BUF_SIZE);
+ 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);
static inline int input_available_p(struct tty_struct *tty, int amt)
{
+ tty_flush_to_ldisc(tty);
if (tty->icanon) {
if (tty->canon_data)
return 1;
* @b: user data
* @nr: size of data
*
- * Helper function to speed up read_chan. It is only called when
+ * Helper function to speed up n_tty_read. It is only called when
* ICANON is off; it copies characters straight from the tty queue to
* user space directly. It can be profitably called twice; once to
* drain the space from the tail pointer to the (physical) end of the
* 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
+ * Called under the tty->atomic_read_lock sem
*
*/
-
-static inline int copy_from_read_buf(struct tty_struct *tty,
+
+static int copy_from_read_buf(struct tty_struct *tty,
unsigned char __user **b,
size_t *nr)
n = min(*nr, n);
spin_unlock_irqrestore(&tty->read_lock, flags);
if (n) {
- mb();
retval = copy_to_user(*b, &tty->read_buf[tty->read_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;
return retval;
}
-extern ssize_t redirected_tty_write(struct file *,const char *,size_t,loff_t *);
+extern ssize_t redirected_tty_write(struct file *, const char __user *,
+ size_t, loff_t *);
/**
* job_control - check job control
* @file: file handle
*
* Perform job control management checks on this file/tty descriptor
- * and if appropriate send any needed signals and return a negative
+ * 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 ?
*/
-
+
static int job_control(struct tty_struct *tty, struct file *file)
{
/* Job control check -- must be done at start and after
/* don't stop on /dev/console */
if (file->f_op->write != redirected_tty_write &&
current->signal->tty == tty) {
- if (tty->pgrp <= 0)
- printk("read_chan: tty->pgrp <= 0!\n");
- else if (process_group(current) != tty->pgrp) {
+ 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_orphaned_pgrp(process_group(current)))
+ is_current_pgrp_orphaned())
return -EIO;
- kill_pg(process_group(current), SIGTTIN, 1);
+ kill_pgrp(task_pgrp(current), SIGTTIN, 1);
+ set_thread_flag(TIF_SIGPENDING);
return -ERESTARTSYS;
}
}
return 0;
}
-
+
/**
- * read_chan - read function for tty
+ * n_tty_read - read function for tty
* @tty: tty device
* @file: file object
* @buf: userspace buffer pointer
*
* This code must be sure never to sleep through a hangup.
*/
-
-static ssize_t read_chan(struct tty_struct *tty, struct file *file,
+
+static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
unsigned char __user *buf, size_t nr)
{
unsigned char __user *b = buf;
ssize_t size;
long timeout;
unsigned long flags;
+ int packet;
do_it_again:
- if (!tty->read_buf) {
- printk("n_tty_read_chan: called with read_buf == NULL?!?\n");
- return -EIO;
- }
+ BUG_ON(!tty->read_buf);
c = job_control(tty, file);
- if(c < 0)
+ 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))
+ if (!mutex_trylock(&tty->atomic_read_lock))
return -EAGAIN;
- }
- else {
- if (down_interruptible(&tty->atomic_read))
+ } else {
+ if (mutex_lock_interruptible(&tty->atomic_read_lock))
return -ERESTARTSYS;
}
+ packet = tty->packet;
add_wait_queue(&tty->read_wait, &wait);
- set_bit(TTY_DONT_FLIP, &tty->flags);
while (nr) {
/* First test for status change. */
- if (tty->packet && tty->link->ctrl_status) {
+ if (packet && tty->link->ctrl_status) {
unsigned char cs;
if (b != buf)
break;
+ spin_lock_irqsave(&tty->link->ctrl_lock, flags);
cs = tty->link->ctrl_status;
tty->link->ctrl_status = 0;
- if (put_user(cs, b++)) {
+ spin_unlock_irqrestore(&tty->link->ctrl_lock, flags);
+ if (tty_put_user(tty, cs, b++)) {
retval = -EFAULT;
b--;
break;
so that any interrupt will set the state back to
TASK_RUNNING. */
set_current_state(TASK_INTERRUPTIBLE);
-
+
if (((minimum - (b - buf)) < tty->minimum_to_wake) &&
((minimum - (b - buf)) >= 1))
tty->minimum_to_wake = (minimum - (b - buf));
-
+
if (!input_available_p(tty, 0)) {
if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) {
retval = -EIO;
retval = -ERESTARTSYS;
break;
}
- clear_bit(TTY_DONT_FLIP, &tty->flags);
+ /* FIXME: does n_tty_set_room need locking ? */
+ n_tty_set_room(tty);
timeout = schedule_timeout(timeout);
- set_bit(TTY_DONT_FLIP, &tty->flags);
continue;
}
__set_current_state(TASK_RUNNING);
/* Deal with packet mode. */
- if (tty->packet && b == buf) {
- if (put_user(TIOCPKT_DATA, b++)) {
+ if (packet && b == buf) {
+ if (tty_put_user(tty, TIOCPKT_DATA, b++)) {
retval = -EFAULT;
b--;
break;
if (tty->icanon) {
/* N.B. avoid overrun if nr == 0 */
while (nr && tty->read_cnt) {
- int eol;
+ int eol;
eol = test_and_clear_bit(tty->read_tail,
tty->read_flags);
spin_unlock_irqrestore(&tty->read_lock, flags);
if (!eol || (c != __DISABLED_CHAR)) {
- if (put_user(c, b++)) {
+ if (tty_put_user(tty, c, b++)) {
retval = -EFAULT;
b--;
break;
}
nr--;
}
- if (eol)
+ if (eol) {
+ tty_audit_push(tty);
break;
+ }
}
if (retval)
break;
} else {
int uncopied;
+ /* The copy function takes the read lock and handles
+ locking internally for this case */
uncopied = copy_from_read_buf(tty, &b, &nr);
uncopied += copy_from_read_buf(tty, &b, &nr);
if (uncopied) {
* 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)
+ if (n_tty_chars_in_buffer(tty) <= TTY_THRESHOLD_UNTHROTTLE) {
+ n_tty_set_room(tty);
check_unthrottle(tty);
+ }
if (b - buf >= minimum)
break;
if (time)
timeout = time;
}
- clear_bit(TTY_DONT_FLIP, &tty->flags);
- up(&tty->atomic_read);
+ mutex_unlock(&tty->atomic_read_lock);
remove_wait_queue(&tty->read_wait, &wait);
if (!waitqueue_active(&tty->read_wait))
if (size) {
retval = size;
if (nr)
- clear_bit(TTY_PUSH, &tty->flags);
+ clear_bit(TTY_PUSH, &tty->flags);
} else if (test_and_clear_bit(TTY_PUSH, &tty->flags))
goto do_it_again;
+ n_tty_set_room(tty);
return retval;
}
/**
- * write_chan - write function for tty
+ * n_tty_write - 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
+ * 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.
+ * and other such events. Since the receive code will echo characters,
+ * thus calling driver write methods, the output_lock is used in
+ * the output processing functions called here as well as in the
+ * echo processing function to protect the column state and space
+ * left in the buffer.
*
* This code must be sure never to sleep through a hangup.
+ *
+ * Locking: output_lock to protect column state and space left
+ * (note that the process_output*() functions take this
+ * lock themselves)
*/
-
-static ssize_t write_chan(struct tty_struct * tty, struct file * file,
- const unsigned char * buf, size_t nr)
+
+static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
+ const unsigned char *buf, size_t nr)
{
const unsigned char *b = buf;
DECLARE_WAITQUEUE(wait, current);
return retval;
}
+ /* Write out any echoed characters that are still pending */
+ process_echoes(tty);
+
add_wait_queue(&tty->write_wait, &wait);
while (1) {
set_current_state(TASK_INTERRUPTIBLE);
}
if (O_OPOST(tty) && !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) {
while (nr > 0) {
- ssize_t num = opost_block(tty, b, nr);
+ ssize_t num = process_output_block(tty, b, nr);
if (num < 0) {
if (num == -EAGAIN)
break;
if (nr == 0)
break;
c = *b;
- if (opost(c, tty) < 0)
+ if (process_output(c, tty) < 0)
break;
b++; nr--;
}
- if (tty->driver->flush_chars)
- tty->driver->flush_chars(tty);
+ if (tty->ops->flush_chars)
+ tty->ops->flush_chars(tty);
} else {
while (nr > 0) {
- c = tty->driver->write(tty, b, nr);
+ c = tty->ops->write(tty, b, nr);
if (c < 0) {
retval = c;
goto break_out;
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);
return (b - buf) ? b - buf : retval;
}
/**
- * normal_poll - poll method for N_TTY
+ * n_tty_poll - poll method for N_TTY
* @tty: terminal device
* @file: file accessing it
* @wait: poll table
*
* 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)
+
+static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file,
+ poll_table *wait)
{
unsigned int mask = 0;
else
tty->minimum_to_wake = 1;
}
- if (tty->driver->chars_in_buffer(tty) < WAKEUP_CHARS &&
- tty->driver->write_room(tty) > 0)
+ if (tty->ops->write && !tty_is_writelocked(tty) &&
+ tty_chars_in_buffer(tty) < WAKEUP_CHARS &&
+ tty_write_room(tty) > 0)
mask |= POLLOUT | POLLWRNORM;
return mask;
}
-struct tty_ldisc tty_ldisc_N_TTY = {
- TTY_LDISC_MAGIC, /* magic */
- "n_tty", /* name */
- 0, /* num */
- 0, /* flags */
- n_tty_open, /* open */
- n_tty_close, /* close */
- n_tty_flush_buffer, /* flush_buffer */
- n_tty_chars_in_buffer, /* chars_in_buffer */
- read_chan, /* read */
- write_chan, /* write */
- 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 */
+static unsigned long inq_canon(struct tty_struct *tty)
+{
+ int nr, head, tail;
+
+ if (!tty->canon_data)
+ return 0;
+ head = tty->canon_head;
+ tail = tty->read_tail;
+ nr = (head - tail) & (N_TTY_BUF_SIZE-1);
+ /* Skip EOF-chars.. */
+ while (head != tail) {
+ if (test_bit(tail, tty->read_flags) &&
+ tty->read_buf[tail] == __DISABLED_CHAR)
+ nr--;
+ tail = (tail+1) & (N_TTY_BUF_SIZE-1);
+ }
+ return nr;
+}
+
+static int n_tty_ioctl(struct tty_struct *tty, struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ int retval;
+
+ switch (cmd) {
+ case TIOCOUTQ:
+ return put_user(tty_chars_in_buffer(tty), (int __user *) arg);
+ case TIOCINQ:
+ /* FIXME: Locking */
+ retval = tty->read_cnt;
+ if (L_ICANON(tty))
+ retval = inq_canon(tty);
+ return put_user(retval, (unsigned int __user *) arg);
+ default:
+ return n_tty_ioctl_helper(tty, file, cmd, arg);
+ }
+}
+
+struct tty_ldisc_ops tty_ldisc_N_TTY = {
+ .magic = TTY_LDISC_MAGIC,
+ .name = "n_tty",
+ .open = n_tty_open,
+ .close = n_tty_close,
+ .flush_buffer = n_tty_flush_buffer,
+ .chars_in_buffer = n_tty_chars_in_buffer,
+ .read = n_tty_read,
+ .write = n_tty_write,
+ .ioctl = n_tty_ioctl,
+ .set_termios = n_tty_set_termios,
+ .poll = n_tty_poll,
+ .receive_buf = n_tty_receive_buf,
+ .write_wakeup = n_tty_write_wakeup
};
+/**
+ * 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
+ * methods.
+ */
+
+void n_tty_inherit_ops(struct tty_ldisc_ops *ops)
+{
+ *ops = tty_ldisc_N_TTY;
+ ops->owner = NULL;
+ ops->refcount = ops->flags = 0;
+}
+EXPORT_SYMBOL_GPL(n_tty_inherit_ops);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff