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cadf748690
WARN_RATELIMIT() expects the warning to end with a newline if one is needed. Not doing so results in odd looking warnings such as: [ 1339.454272] tty is NULLPid: 7147, comm: kworker/4:0 Tainted: G W 3.7.0-rc2-next-20121025-sasha-00001-g673f98e-dirty #75 Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2202 lines
55 KiB
C
2202 lines
55 KiB
C
/*
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* n_tty.c --- implements the N_TTY line discipline.
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*
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* This code used to be in tty_io.c, but things are getting hairy
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* enough that it made sense to split things off. (The N_TTY
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* processing has changed so much that it's hardly recognizable,
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* anyway...)
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*
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* Note that the open routine for N_TTY is guaranteed never to return
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* an error. This is because Linux will fall back to setting a line
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* to N_TTY if it can not switch to any other line discipline.
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*
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* Written by Theodore Ts'o, Copyright 1994.
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*
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* This file also contains code originally written by Linus Torvalds,
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* Copyright 1991, 1992, 1993, and by Julian Cowley, Copyright 1994.
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*
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* This file may be redistributed under the terms of the GNU General Public
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* License.
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*
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* Reduced memory usage for older ARM systems - Russell King.
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*
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* 2000/01/20 Fixed SMP locking on put_tty_queue using bits of
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* the patch by Andrew J. Kroll <ag784@freenet.buffalo.edu>
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* who actually finally proved there really was a race.
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*
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* 2002/03/18 Implemented n_tty_wakeup to send SIGIO POLL_OUTs to
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* waiting writing processes-Sapan Bhatia <sapan@corewars.org>.
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* Also fixed a bug in BLOCKING mode where n_tty_write returns
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* EAGAIN
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*/
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#include <linux/types.h>
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#include <linux/major.h>
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#include <linux/errno.h>
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#include <linux/signal.h>
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#include <linux/fcntl.h>
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#include <linux/sched.h>
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#include <linux/interrupt.h>
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#include <linux/tty.h>
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#include <linux/timer.h>
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#include <linux/ctype.h>
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#include <linux/mm.h>
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#include <linux/string.h>
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#include <linux/slab.h>
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#include <linux/poll.h>
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#include <linux/bitops.h>
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#include <linux/audit.h>
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#include <linux/file.h>
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#include <linux/uaccess.h>
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#include <linux/module.h>
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/* number of characters left in xmit buffer before select has we have room */
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#define WAKEUP_CHARS 256
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/*
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* This defines the low- and high-watermarks for throttling and
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* unthrottling the TTY driver. These watermarks are used for
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* controlling the space in the read buffer.
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*/
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#define TTY_THRESHOLD_THROTTLE 128 /* now based on remaining room */
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#define TTY_THRESHOLD_UNTHROTTLE 128
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/*
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* Special byte codes used in the echo buffer to represent operations
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* or special handling of characters. Bytes in the echo buffer that
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* are not part of such special blocks are treated as normal character
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* codes.
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*/
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#define ECHO_OP_START 0xff
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#define ECHO_OP_MOVE_BACK_COL 0x80
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#define ECHO_OP_SET_CANON_COL 0x81
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#define ECHO_OP_ERASE_TAB 0x82
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struct n_tty_data {
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unsigned int column;
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unsigned long overrun_time;
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int num_overrun;
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unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1;
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unsigned char echo_overrun:1;
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DECLARE_BITMAP(process_char_map, 256);
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DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE);
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char *read_buf;
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int read_head;
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int read_tail;
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int read_cnt;
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unsigned char *echo_buf;
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unsigned int echo_pos;
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unsigned int echo_cnt;
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int canon_data;
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unsigned long canon_head;
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unsigned int canon_column;
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struct mutex atomic_read_lock;
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struct mutex output_lock;
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struct mutex echo_lock;
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spinlock_t read_lock;
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};
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static inline int tty_put_user(struct tty_struct *tty, unsigned char x,
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unsigned char __user *ptr)
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{
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struct n_tty_data *ldata = tty->disc_data;
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tty_audit_add_data(tty, &x, 1, ldata->icanon);
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return put_user(x, ptr);
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}
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/**
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* n_tty_set__room - receive space
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* @tty: terminal
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*
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* Called by the driver to find out how much data it is
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* permitted to feed to the line discipline without any being lost
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* and thus to manage flow control. Not serialized. Answers for the
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* "instant".
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*/
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static void n_tty_set_room(struct tty_struct *tty)
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{
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struct n_tty_data *ldata = tty->disc_data;
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int left;
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int old_left;
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/* ldata->read_cnt is not read locked ? */
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if (I_PARMRK(tty)) {
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/* Multiply read_cnt by 3, since each byte might take up to
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* three times as many spaces when PARMRK is set (depending on
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* its flags, e.g. parity error). */
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left = N_TTY_BUF_SIZE - ldata->read_cnt * 3 - 1;
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} else
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left = N_TTY_BUF_SIZE - ldata->read_cnt - 1;
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/*
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* If we are doing input canonicalization, and there are no
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* pending newlines, let characters through without limit, so
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* that erase characters will be handled. Other excess
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* characters will be beeped.
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*/
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if (left <= 0)
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left = ldata->icanon && !ldata->canon_data;
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old_left = tty->receive_room;
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tty->receive_room = left;
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/* Did this open up the receive buffer? We may need to flip */
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if (left && !old_left) {
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WARN_RATELIMIT(tty->port->itty == NULL,
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"scheduling with invalid itty\n");
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schedule_work(&tty->port->buf.work);
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}
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}
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static void put_tty_queue_nolock(unsigned char c, struct n_tty_data *ldata)
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{
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if (ldata->read_cnt < N_TTY_BUF_SIZE) {
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ldata->read_buf[ldata->read_head] = c;
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ldata->read_head = (ldata->read_head + 1) & (N_TTY_BUF_SIZE-1);
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ldata->read_cnt++;
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}
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}
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/**
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* put_tty_queue - add character to tty
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* @c: character
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* @ldata: n_tty data
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*
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* Add a character to the tty read_buf queue. This is done under the
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* read_lock to serialize character addition and also to protect us
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* against parallel reads or flushes
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*/
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static void put_tty_queue(unsigned char c, struct n_tty_data *ldata)
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{
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unsigned long flags;
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/*
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* The problem of stomping on the buffers ends here.
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* Why didn't anyone see this one coming? --AJK
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*/
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spin_lock_irqsave(&ldata->read_lock, flags);
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put_tty_queue_nolock(c, ldata);
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spin_unlock_irqrestore(&ldata->read_lock, flags);
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}
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/**
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* check_unthrottle - allow new receive data
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* @tty; tty device
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*
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* Check whether to call the driver unthrottle functions
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*
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* Can sleep, may be called under the atomic_read_lock mutex but
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* this is not guaranteed.
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*/
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static void check_unthrottle(struct tty_struct *tty)
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{
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if (tty->count)
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tty_unthrottle(tty);
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}
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/**
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* reset_buffer_flags - reset buffer state
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* @tty: terminal to reset
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*
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* Reset the read buffer counters, clear the flags,
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* and make sure the driver is unthrottled. Called
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* from n_tty_open() and n_tty_flush_buffer().
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*
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* Locking: tty_read_lock for read fields.
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*/
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static void reset_buffer_flags(struct tty_struct *tty)
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{
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struct n_tty_data *ldata = tty->disc_data;
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unsigned long flags;
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spin_lock_irqsave(&ldata->read_lock, flags);
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ldata->read_head = ldata->read_tail = ldata->read_cnt = 0;
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spin_unlock_irqrestore(&ldata->read_lock, flags);
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mutex_lock(&ldata->echo_lock);
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ldata->echo_pos = ldata->echo_cnt = ldata->echo_overrun = 0;
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mutex_unlock(&ldata->echo_lock);
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ldata->canon_head = ldata->canon_data = ldata->erasing = 0;
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bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE);
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n_tty_set_room(tty);
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}
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/**
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* n_tty_flush_buffer - clean input queue
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* @tty: terminal device
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*
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* Flush the input buffer. Called when the line discipline is
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* being closed, when the tty layer wants the buffer flushed (eg
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* at hangup) or when the N_TTY line discipline internally has to
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* clean the pending queue (for example some signals).
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*
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* Locking: ctrl_lock, read_lock.
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*/
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static void n_tty_flush_buffer(struct tty_struct *tty)
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{
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unsigned long flags;
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/* clear everything and unthrottle the driver */
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reset_buffer_flags(tty);
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if (!tty->link)
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return;
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spin_lock_irqsave(&tty->ctrl_lock, flags);
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if (tty->link->packet) {
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tty->ctrl_status |= TIOCPKT_FLUSHREAD;
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wake_up_interruptible(&tty->link->read_wait);
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}
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spin_unlock_irqrestore(&tty->ctrl_lock, flags);
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}
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/**
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* n_tty_chars_in_buffer - report available bytes
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* @tty: tty device
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*
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* Report the number of characters buffered to be delivered to user
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* at this instant in time.
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*
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* Locking: read_lock
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*/
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static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty)
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{
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struct n_tty_data *ldata = tty->disc_data;
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unsigned long flags;
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ssize_t n = 0;
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spin_lock_irqsave(&ldata->read_lock, flags);
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if (!ldata->icanon) {
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n = ldata->read_cnt;
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} else if (ldata->canon_data) {
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n = (ldata->canon_head > ldata->read_tail) ?
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ldata->canon_head - ldata->read_tail :
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ldata->canon_head + (N_TTY_BUF_SIZE - ldata->read_tail);
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}
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spin_unlock_irqrestore(&ldata->read_lock, flags);
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return n;
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}
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/**
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* is_utf8_continuation - utf8 multibyte check
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* @c: byte to check
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*
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* Returns true if the utf8 character 'c' is a multibyte continuation
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* character. We use this to correctly compute the on screen size
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* of the character when printing
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*/
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static inline int is_utf8_continuation(unsigned char c)
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{
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return (c & 0xc0) == 0x80;
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}
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/**
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* is_continuation - multibyte check
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* @c: byte to check
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*
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* Returns true if the utf8 character 'c' is a multibyte continuation
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* character and the terminal is in unicode mode.
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*/
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static inline int is_continuation(unsigned char c, struct tty_struct *tty)
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{
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return I_IUTF8(tty) && is_utf8_continuation(c);
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}
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/**
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* do_output_char - output one character
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* @c: character (or partial unicode symbol)
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* @tty: terminal device
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* @space: space available in tty driver write buffer
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*
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* This is a helper function that handles one output character
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* (including special characters like TAB, CR, LF, etc.),
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* doing OPOST processing and putting the results in the
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* tty driver's write buffer.
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*
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* Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY
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* and NLDLY. They simply aren't relevant in the world today.
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* If you ever need them, add them here.
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*
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* Returns the number of bytes of buffer space used or -1 if
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* no space left.
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*
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* Locking: should be called under the output_lock to protect
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* the column state and space left in the buffer
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*/
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static int do_output_char(unsigned char c, struct tty_struct *tty, int space)
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{
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struct n_tty_data *ldata = tty->disc_data;
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int spaces;
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|
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if (!space)
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return -1;
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|
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switch (c) {
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case '\n':
|
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if (O_ONLRET(tty))
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ldata->column = 0;
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if (O_ONLCR(tty)) {
|
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if (space < 2)
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return -1;
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ldata->canon_column = ldata->column = 0;
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tty->ops->write(tty, "\r\n", 2);
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return 2;
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}
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ldata->canon_column = ldata->column;
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break;
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case '\r':
|
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if (O_ONOCR(tty) && ldata->column == 0)
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return 0;
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if (O_OCRNL(tty)) {
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c = '\n';
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if (O_ONLRET(tty))
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ldata->canon_column = ldata->column = 0;
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break;
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}
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ldata->canon_column = ldata->column = 0;
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break;
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case '\t':
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spaces = 8 - (ldata->column & 7);
|
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if (O_TABDLY(tty) == XTABS) {
|
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if (space < spaces)
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return -1;
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ldata->column += spaces;
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tty->ops->write(tty, " ", spaces);
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return spaces;
|
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}
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ldata->column += spaces;
|
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break;
|
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case '\b':
|
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if (ldata->column > 0)
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ldata->column--;
|
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break;
|
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default:
|
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if (!iscntrl(c)) {
|
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if (O_OLCUC(tty))
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c = toupper(c);
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if (!is_continuation(c, tty))
|
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ldata->column++;
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}
|
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break;
|
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}
|
|
|
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tty_put_char(tty, c);
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return 1;
|
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}
|
|
|
|
/**
|
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* process_output - output post processor
|
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* @c: character (or partial unicode symbol)
|
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* @tty: terminal device
|
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*
|
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* Output one character with OPOST processing.
|
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* Returns -1 when the output device is full and the character
|
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* must be retried.
|
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*
|
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* Locking: output_lock to protect column state and space left
|
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* (also, this is called from n_tty_write under the
|
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* tty layer write lock)
|
|
*/
|
|
|
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static int process_output(unsigned char c, struct tty_struct *tty)
|
|
{
|
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struct n_tty_data *ldata = tty->disc_data;
|
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int space, retval;
|
|
|
|
mutex_lock(&ldata->output_lock);
|
|
|
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space = tty_write_room(tty);
|
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retval = do_output_char(c, tty, space);
|
|
|
|
mutex_unlock(&ldata->output_lock);
|
|
if (retval < 0)
|
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return -1;
|
|
else
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* process_output_block - block post processor
|
|
* @tty: terminal device
|
|
* @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.
|
|
*
|
|
* 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 process_output_block(struct tty_struct *tty,
|
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const unsigned char *buf, unsigned int nr)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
int space;
|
|
int i;
|
|
const unsigned char *cp;
|
|
|
|
mutex_lock(&ldata->output_lock);
|
|
|
|
space = tty_write_room(tty);
|
|
if (!space) {
|
|
mutex_unlock(&ldata->output_lock);
|
|
return 0;
|
|
}
|
|
if (nr > space)
|
|
nr = space;
|
|
|
|
for (i = 0, cp = buf; i < nr; i++, cp++) {
|
|
unsigned char c = *cp;
|
|
|
|
switch (c) {
|
|
case '\n':
|
|
if (O_ONLRET(tty))
|
|
ldata->column = 0;
|
|
if (O_ONLCR(tty))
|
|
goto break_out;
|
|
ldata->canon_column = ldata->column;
|
|
break;
|
|
case '\r':
|
|
if (O_ONOCR(tty) && ldata->column == 0)
|
|
goto break_out;
|
|
if (O_OCRNL(tty))
|
|
goto break_out;
|
|
ldata->canon_column = ldata->column = 0;
|
|
break;
|
|
case '\t':
|
|
goto break_out;
|
|
case '\b':
|
|
if (ldata->column > 0)
|
|
ldata->column--;
|
|
break;
|
|
default:
|
|
if (!iscntrl(c)) {
|
|
if (O_OLCUC(tty))
|
|
goto break_out;
|
|
if (!is_continuation(c, tty))
|
|
ldata->column++;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
break_out:
|
|
i = tty->ops->write(tty, buf, i);
|
|
|
|
mutex_unlock(&ldata->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)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
int space, nr;
|
|
unsigned char c;
|
|
unsigned char *cp, *buf_end;
|
|
|
|
if (!ldata->echo_cnt)
|
|
return;
|
|
|
|
mutex_lock(&ldata->output_lock);
|
|
mutex_lock(&ldata->echo_lock);
|
|
|
|
space = tty_write_room(tty);
|
|
|
|
buf_end = ldata->echo_buf + N_TTY_BUF_SIZE;
|
|
cp = ldata->echo_buf + ldata->echo_pos;
|
|
nr = ldata->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 += ldata->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 (ldata->column > 0)
|
|
ldata->column--;
|
|
}
|
|
cp += 3;
|
|
nr -= 3;
|
|
break;
|
|
|
|
case ECHO_OP_SET_CANON_COL:
|
|
ldata->canon_column = ldata->column;
|
|
cp += 2;
|
|
nr -= 2;
|
|
break;
|
|
|
|
case ECHO_OP_MOVE_BACK_COL:
|
|
if (ldata->column > 0)
|
|
ldata->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);
|
|
ldata->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);
|
|
ldata->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) {
|
|
ldata->echo_pos = 0;
|
|
ldata->echo_cnt = 0;
|
|
ldata->echo_overrun = 0;
|
|
} else {
|
|
int num_processed = ldata->echo_cnt - nr;
|
|
ldata->echo_pos += num_processed;
|
|
ldata->echo_pos &= N_TTY_BUF_SIZE - 1;
|
|
ldata->echo_cnt = nr;
|
|
if (num_processed > 0)
|
|
ldata->echo_overrun = 0;
|
|
}
|
|
|
|
mutex_unlock(&ldata->echo_lock);
|
|
mutex_unlock(&ldata->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
|
|
* @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 n_tty_data *ldata)
|
|
{
|
|
int new_byte_pos;
|
|
|
|
if (ldata->echo_cnt == N_TTY_BUF_SIZE) {
|
|
/* Circular buffer is already at capacity */
|
|
new_byte_pos = ldata->echo_pos;
|
|
|
|
/*
|
|
* Since the buffer start position needs to be advanced,
|
|
* be sure to step by a whole operation byte group.
|
|
*/
|
|
if (ldata->echo_buf[ldata->echo_pos] == ECHO_OP_START) {
|
|
if (ldata->echo_buf[(ldata->echo_pos + 1) &
|
|
(N_TTY_BUF_SIZE - 1)] ==
|
|
ECHO_OP_ERASE_TAB) {
|
|
ldata->echo_pos += 3;
|
|
ldata->echo_cnt -= 2;
|
|
} else {
|
|
ldata->echo_pos += 2;
|
|
ldata->echo_cnt -= 1;
|
|
}
|
|
} else {
|
|
ldata->echo_pos++;
|
|
}
|
|
ldata->echo_pos &= N_TTY_BUF_SIZE - 1;
|
|
|
|
ldata->echo_overrun = 1;
|
|
} else {
|
|
new_byte_pos = ldata->echo_pos + ldata->echo_cnt;
|
|
new_byte_pos &= N_TTY_BUF_SIZE - 1;
|
|
ldata->echo_cnt++;
|
|
}
|
|
|
|
ldata->echo_buf[new_byte_pos] = c;
|
|
}
|
|
|
|
/**
|
|
* echo_move_back_col - add operation to move back a column
|
|
* @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 n_tty_data *ldata)
|
|
{
|
|
mutex_lock(&ldata->echo_lock);
|
|
add_echo_byte(ECHO_OP_START, ldata);
|
|
add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata);
|
|
mutex_unlock(&ldata->echo_lock);
|
|
}
|
|
|
|
/**
|
|
* echo_set_canon_col - add operation to set the canon column
|
|
* @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 n_tty_data *ldata)
|
|
{
|
|
mutex_lock(&ldata->echo_lock);
|
|
add_echo_byte(ECHO_OP_START, ldata);
|
|
add_echo_byte(ECHO_OP_SET_CANON_COL, ldata);
|
|
mutex_unlock(&ldata->echo_lock);
|
|
}
|
|
|
|
/**
|
|
* 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
|
|
* @ldata: n_tty data
|
|
*
|
|
* 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 void echo_erase_tab(unsigned int num_chars, int after_tab,
|
|
struct n_tty_data *ldata)
|
|
{
|
|
mutex_lock(&ldata->echo_lock);
|
|
|
|
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;
|
|
|
|
/* 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, ldata);
|
|
|
|
mutex_unlock(&ldata->echo_lock);
|
|
}
|
|
|
|
/**
|
|
* 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
|
|
* 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 n_tty_data *ldata)
|
|
{
|
|
mutex_lock(&ldata->echo_lock);
|
|
if (c == ECHO_OP_START) {
|
|
add_echo_byte(ECHO_OP_START, ldata);
|
|
add_echo_byte(ECHO_OP_START, ldata);
|
|
} else {
|
|
add_echo_byte(c, ldata);
|
|
}
|
|
mutex_unlock(&ldata->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)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
|
|
mutex_lock(&ldata->echo_lock);
|
|
|
|
if (c == ECHO_OP_START) {
|
|
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, ldata);
|
|
add_echo_byte(c, ldata);
|
|
}
|
|
|
|
mutex_unlock(&ldata->echo_lock);
|
|
}
|
|
|
|
/**
|
|
* finish_erasing - complete erase
|
|
* @ldata: n_tty data
|
|
*/
|
|
|
|
static inline void finish_erasing(struct n_tty_data *ldata)
|
|
{
|
|
if (ldata->erasing) {
|
|
echo_char_raw('/', ldata);
|
|
ldata->erasing = 0;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* eraser - handle erase function
|
|
* @c: character input
|
|
* @tty: terminal device
|
|
*
|
|
* 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)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
enum { ERASE, WERASE, KILL } kill_type;
|
|
int head, seen_alnums, cnt;
|
|
unsigned long flags;
|
|
|
|
/* FIXME: locking needed ? */
|
|
if (ldata->read_head == ldata->canon_head) {
|
|
/* process_output('\a', tty); */ /* what do you think? */
|
|
return;
|
|
}
|
|
if (c == ERASE_CHAR(tty))
|
|
kill_type = ERASE;
|
|
else if (c == WERASE_CHAR(tty))
|
|
kill_type = WERASE;
|
|
else {
|
|
if (!L_ECHO(tty)) {
|
|
spin_lock_irqsave(&ldata->read_lock, flags);
|
|
ldata->read_cnt -= ((ldata->read_head - ldata->canon_head) &
|
|
(N_TTY_BUF_SIZE - 1));
|
|
ldata->read_head = ldata->canon_head;
|
|
spin_unlock_irqrestore(&ldata->read_lock, flags);
|
|
return;
|
|
}
|
|
if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) {
|
|
spin_lock_irqsave(&ldata->read_lock, flags);
|
|
ldata->read_cnt -= ((ldata->read_head - ldata->canon_head) &
|
|
(N_TTY_BUF_SIZE - 1));
|
|
ldata->read_head = ldata->canon_head;
|
|
spin_unlock_irqrestore(&ldata->read_lock, flags);
|
|
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', ldata);
|
|
return;
|
|
}
|
|
kill_type = KILL;
|
|
}
|
|
|
|
seen_alnums = 0;
|
|
/* FIXME: Locking ?? */
|
|
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 = ldata->read_buf[head];
|
|
} while (is_continuation(c, tty) && head != ldata->canon_head);
|
|
|
|
/* do not partially erase */
|
|
if (is_continuation(c, tty))
|
|
break;
|
|
|
|
if (kill_type == WERASE) {
|
|
/* Equivalent to BSD's ALTWERASE. */
|
|
if (isalnum(c) || c == '_')
|
|
seen_alnums++;
|
|
else if (seen_alnums)
|
|
break;
|
|
}
|
|
cnt = (ldata->read_head - head) & (N_TTY_BUF_SIZE-1);
|
|
spin_lock_irqsave(&ldata->read_lock, flags);
|
|
ldata->read_head = head;
|
|
ldata->read_cnt -= cnt;
|
|
spin_unlock_irqrestore(&ldata->read_lock, flags);
|
|
if (L_ECHO(tty)) {
|
|
if (L_ECHOPRT(tty)) {
|
|
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(ldata->read_buf[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 = ldata->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 != ldata->canon_head) {
|
|
tail = (tail-1) & (N_TTY_BUF_SIZE-1);
|
|
c = ldata->read_buf[tail];
|
|
if (c == '\t') {
|
|
after_tab = 1;
|
|
break;
|
|
} else if (iscntrl(c)) {
|
|
if (L_ECHOCTL(tty))
|
|
num_chars += 2;
|
|
} else if (!is_continuation(c, tty)) {
|
|
num_chars++;
|
|
}
|
|
}
|
|
echo_erase_tab(num_chars, after_tab, ldata);
|
|
} else {
|
|
if (iscntrl(c) && L_ECHOCTL(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', ldata);
|
|
echo_char_raw(' ', ldata);
|
|
echo_char_raw('\b', ldata);
|
|
}
|
|
}
|
|
}
|
|
if (kill_type == ERASE)
|
|
break;
|
|
}
|
|
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.
|
|
*
|
|
* Locking: ctrl_lock, read_lock (both via flush buffer)
|
|
*/
|
|
|
|
static inline void isig(int sig, struct tty_struct *tty, int flush)
|
|
{
|
|
if (tty->pgrp)
|
|
kill_pgrp(tty->pgrp, sig, 1);
|
|
if (flush || !L_NOFLSH(tty)) {
|
|
n_tty_flush_buffer(tty);
|
|
tty_driver_flush_buffer(tty);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* n_tty_receive_break - handle break
|
|
* @tty: terminal
|
|
*
|
|
* An RS232 break event has been hit in the incoming bitstream. This
|
|
* can cause a variety of events depending upon the termios settings.
|
|
*
|
|
* Called from the receive_buf path so single threaded.
|
|
*/
|
|
|
|
static inline void n_tty_receive_break(struct tty_struct *tty)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
|
|
if (I_IGNBRK(tty))
|
|
return;
|
|
if (I_BRKINT(tty)) {
|
|
isig(SIGINT, tty, 1);
|
|
return;
|
|
}
|
|
if (I_PARMRK(tty)) {
|
|
put_tty_queue('\377', ldata);
|
|
put_tty_queue('\0', ldata);
|
|
}
|
|
put_tty_queue('\0', ldata);
|
|
wake_up_interruptible(&tty->read_wait);
|
|
}
|
|
|
|
/**
|
|
* n_tty_receive_overrun - handle overrun reporting
|
|
* @tty: terminal
|
|
*
|
|
* Data arrived faster than we could process it. While the tty
|
|
* driver has flagged this the bits that were missed are gone
|
|
* forever.
|
|
*
|
|
* Called from the receive_buf path so single threaded. Does not
|
|
* need locking as num_overrun and overrun_time are function
|
|
* private.
|
|
*/
|
|
|
|
static inline void n_tty_receive_overrun(struct tty_struct *tty)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
char buf[64];
|
|
|
|
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),
|
|
ldata->num_overrun);
|
|
ldata->overrun_time = jiffies;
|
|
ldata->num_overrun = 0;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* n_tty_receive_parity_error - error notifier
|
|
* @tty: terminal device
|
|
* @c: character
|
|
*
|
|
* Process a parity error and queue the right data to indicate
|
|
* the error case if necessary. Locking as per n_tty_receive_buf.
|
|
*/
|
|
static inline void n_tty_receive_parity_error(struct tty_struct *tty,
|
|
unsigned char c)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
|
|
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 if (I_INPCK(tty))
|
|
put_tty_queue('\0', ldata);
|
|
else
|
|
put_tty_queue(c, ldata);
|
|
wake_up_interruptible(&tty->read_wait);
|
|
}
|
|
|
|
/**
|
|
* n_tty_receive_char - perform processing
|
|
* @tty: terminal device
|
|
* @c: character
|
|
*
|
|
* Process an individual character of input received from the driver.
|
|
* This is serialized with respect to itself by the rules for the
|
|
* driver above.
|
|
*/
|
|
|
|
static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
unsigned long flags;
|
|
int parmrk;
|
|
|
|
if (ldata->raw) {
|
|
put_tty_queue(c, ldata);
|
|
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, ldata);
|
|
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, ldata->process_char_map) || ldata->lnext) {
|
|
ldata->lnext = 0;
|
|
parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0;
|
|
if (ldata->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(ldata);
|
|
/* Record the column of first canon char. */
|
|
if (ldata->canon_head == ldata->read_head)
|
|
echo_set_canon_col(ldata);
|
|
echo_char(c, tty);
|
|
process_echoes(tty);
|
|
}
|
|
if (parmrk)
|
|
put_tty_queue(c, ldata);
|
|
put_tty_queue(c, ldata);
|
|
return;
|
|
}
|
|
|
|
if (I_IXON(tty)) {
|
|
if (c == START_CHAR(tty)) {
|
|
start_tty(tty);
|
|
process_echoes(tty);
|
|
return;
|
|
}
|
|
if (c == STOP_CHAR(tty)) {
|
|
stop_tty(tty);
|
|
return;
|
|
}
|
|
}
|
|
|
|
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 == '\r') {
|
|
if (I_IGNCR(tty))
|
|
return;
|
|
if (I_ICRNL(tty))
|
|
c = '\n';
|
|
} else if (c == '\n' && I_INLCR(tty))
|
|
c = '\r';
|
|
|
|
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;
|
|
}
|
|
if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) {
|
|
ldata->lnext = 1;
|
|
if (L_ECHO(tty)) {
|
|
finish_erasing(ldata);
|
|
if (L_ECHOCTL(tty)) {
|
|
echo_char_raw('^', ldata);
|
|
echo_char_raw('\b', ldata);
|
|
process_echoes(tty);
|
|
}
|
|
}
|
|
return;
|
|
}
|
|
if (c == REPRINT_CHAR(tty) && L_ECHO(tty) &&
|
|
L_IEXTEN(tty)) {
|
|
unsigned long tail = ldata->canon_head;
|
|
|
|
finish_erasing(ldata);
|
|
echo_char(c, tty);
|
|
echo_char_raw('\n', ldata);
|
|
while (tail != ldata->read_head) {
|
|
echo_char(ldata->read_buf[tail], tty);
|
|
tail = (tail+1) & (N_TTY_BUF_SIZE-1);
|
|
}
|
|
process_echoes(tty);
|
|
return;
|
|
}
|
|
if (c == '\n') {
|
|
if (ldata->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', ldata);
|
|
process_echoes(tty);
|
|
}
|
|
goto handle_newline;
|
|
}
|
|
if (c == EOF_CHAR(tty)) {
|
|
if (ldata->read_cnt >= N_TTY_BUF_SIZE)
|
|
return;
|
|
if (ldata->canon_head != ldata->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 (ldata->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 (ldata->canon_head == ldata->read_head)
|
|
echo_set_canon_col(ldata);
|
|
echo_char(c, tty);
|
|
process_echoes(tty);
|
|
}
|
|
/*
|
|
* XXX does PARMRK doubling happen for
|
|
* EOL_CHAR and EOL2_CHAR?
|
|
*/
|
|
if (parmrk)
|
|
put_tty_queue(c, ldata);
|
|
|
|
handle_newline:
|
|
spin_lock_irqsave(&ldata->read_lock, flags);
|
|
set_bit(ldata->read_head, ldata->read_flags);
|
|
put_tty_queue_nolock(c, ldata);
|
|
ldata->canon_head = ldata->read_head;
|
|
ldata->canon_data++;
|
|
spin_unlock_irqrestore(&ldata->read_lock, flags);
|
|
kill_fasync(&tty->fasync, SIGIO, POLL_IN);
|
|
if (waitqueue_active(&tty->read_wait))
|
|
wake_up_interruptible(&tty->read_wait);
|
|
return;
|
|
}
|
|
}
|
|
|
|
parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0;
|
|
if (ldata->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(ldata);
|
|
if (c == '\n')
|
|
echo_char_raw('\n', ldata);
|
|
else {
|
|
/* Record the column of first canon char. */
|
|
if (ldata->canon_head == ldata->read_head)
|
|
echo_set_canon_col(ldata);
|
|
echo_char(c, tty);
|
|
}
|
|
process_echoes(tty);
|
|
}
|
|
|
|
if (parmrk)
|
|
put_tty_queue(c, ldata);
|
|
|
|
put_tty_queue(c, ldata);
|
|
}
|
|
|
|
|
|
/**
|
|
* n_tty_write_wakeup - asynchronous I/O notifier
|
|
* @tty: tty device
|
|
*
|
|
* Required for the ptys, serial driver etc. since processes
|
|
* that attach themselves to the master and rely on ASYNC
|
|
* IO must be woken up
|
|
*/
|
|
|
|
static void n_tty_write_wakeup(struct tty_struct *tty)
|
|
{
|
|
if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags))
|
|
kill_fasync(&tty->fasync, SIGIO, POLL_OUT);
|
|
}
|
|
|
|
/**
|
|
* n_tty_receive_buf - data receive
|
|
* @tty: terminal device
|
|
* @cp: buffer
|
|
* @fp: flag buffer
|
|
* @count: characters
|
|
*
|
|
* Called by the terminal driver when a block of characters has
|
|
* been received. This function must be called from soft contexts
|
|
* not from interrupt context. The driver is responsible for making
|
|
* calls one at a time and in order (or using flush_to_ldisc)
|
|
*/
|
|
|
|
static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
|
|
char *fp, int count)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
const unsigned char *p;
|
|
char *f, flags = TTY_NORMAL;
|
|
int i;
|
|
char buf[64];
|
|
unsigned long cpuflags;
|
|
|
|
if (ldata->real_raw) {
|
|
spin_lock_irqsave(&ldata->read_lock, cpuflags);
|
|
i = min(N_TTY_BUF_SIZE - ldata->read_cnt,
|
|
N_TTY_BUF_SIZE - ldata->read_head);
|
|
i = min(count, i);
|
|
memcpy(ldata->read_buf + ldata->read_head, cp, i);
|
|
ldata->read_head = (ldata->read_head + i) & (N_TTY_BUF_SIZE-1);
|
|
ldata->read_cnt += i;
|
|
cp += i;
|
|
count -= i;
|
|
|
|
i = min(N_TTY_BUF_SIZE - ldata->read_cnt,
|
|
N_TTY_BUF_SIZE - ldata->read_head);
|
|
i = min(count, i);
|
|
memcpy(ldata->read_buf + ldata->read_head, cp, i);
|
|
ldata->read_head = (ldata->read_head + i) & (N_TTY_BUF_SIZE-1);
|
|
ldata->read_cnt += i;
|
|
spin_unlock_irqrestore(&ldata->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;
|
|
}
|
|
}
|
|
if (tty->ops->flush_chars)
|
|
tty->ops->flush_chars(tty);
|
|
}
|
|
|
|
n_tty_set_room(tty);
|
|
|
|
if ((!ldata->icanon && (ldata->read_cnt >= tty->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);
|
|
|
|
/* FIXME: there is a tiny race here if the receive room check runs
|
|
before the other work executes and empties the buffer (upping
|
|
the receiving room and unthrottling. We then throttle and get
|
|
stuck. This has been observed and traced down by Vincent Pillet/
|
|
We need to address this when we sort out out the rx path locking */
|
|
}
|
|
|
|
int is_ignored(int sig)
|
|
{
|
|
return (sigismember(¤t->blocked, sig) ||
|
|
current->sighand->action[sig-1].sa.sa_handler == SIG_IGN);
|
|
}
|
|
|
|
/**
|
|
* n_tty_set_termios - termios data changed
|
|
* @tty: terminal
|
|
* @old: previous data
|
|
*
|
|
* Called by the tty layer when the user changes termios flags so
|
|
* that the line discipline can plan ahead. This function cannot sleep
|
|
* and is protected from re-entry by the tty layer. The user is
|
|
* guaranteed that this function will not be re-entered or in progress
|
|
* when the ldisc is closed.
|
|
*
|
|
* Locking: Caller holds tty->termios_mutex
|
|
*/
|
|
|
|
static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
int canon_change = 1;
|
|
|
|
if (old)
|
|
canon_change = (old->c_lflag ^ tty->termios.c_lflag) & ICANON;
|
|
if (canon_change) {
|
|
bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE);
|
|
ldata->canon_head = ldata->read_tail;
|
|
ldata->canon_data = 0;
|
|
ldata->erasing = 0;
|
|
}
|
|
|
|
if (canon_change && !L_ICANON(tty) && ldata->read_cnt)
|
|
wake_up_interruptible(&tty->read_wait);
|
|
|
|
ldata->icanon = (L_ICANON(tty) != 0);
|
|
if (test_bit(TTY_HW_COOK_IN, &tty->flags)) {
|
|
ldata->raw = 1;
|
|
ldata->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)) {
|
|
bitmap_zero(ldata->process_char_map, 256);
|
|
|
|
if (I_IGNCR(tty) || I_ICRNL(tty))
|
|
set_bit('\r', ldata->process_char_map);
|
|
if (I_INLCR(tty))
|
|
set_bit('\n', ldata->process_char_map);
|
|
|
|
if (L_ICANON(tty)) {
|
|
set_bit(ERASE_CHAR(tty), ldata->process_char_map);
|
|
set_bit(KILL_CHAR(tty), ldata->process_char_map);
|
|
set_bit(EOF_CHAR(tty), ldata->process_char_map);
|
|
set_bit('\n', ldata->process_char_map);
|
|
set_bit(EOL_CHAR(tty), ldata->process_char_map);
|
|
if (L_IEXTEN(tty)) {
|
|
set_bit(WERASE_CHAR(tty),
|
|
ldata->process_char_map);
|
|
set_bit(LNEXT_CHAR(tty),
|
|
ldata->process_char_map);
|
|
set_bit(EOL2_CHAR(tty),
|
|
ldata->process_char_map);
|
|
if (L_ECHO(tty))
|
|
set_bit(REPRINT_CHAR(tty),
|
|
ldata->process_char_map);
|
|
}
|
|
}
|
|
if (I_IXON(tty)) {
|
|
set_bit(START_CHAR(tty), ldata->process_char_map);
|
|
set_bit(STOP_CHAR(tty), ldata->process_char_map);
|
|
}
|
|
if (L_ISIG(tty)) {
|
|
set_bit(INTR_CHAR(tty), ldata->process_char_map);
|
|
set_bit(QUIT_CHAR(tty), ldata->process_char_map);
|
|
set_bit(SUSP_CHAR(tty), ldata->process_char_map);
|
|
}
|
|
clear_bit(__DISABLED_CHAR, ldata->process_char_map);
|
|
ldata->raw = 0;
|
|
ldata->real_raw = 0;
|
|
} else {
|
|
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))
|
|
ldata->real_raw = 1;
|
|
else
|
|
ldata->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
|
|
* discipline change. The function will not be called while other
|
|
* ldisc methods are in progress.
|
|
*/
|
|
|
|
static void n_tty_close(struct tty_struct *tty)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
|
|
n_tty_flush_buffer(tty);
|
|
kfree(ldata->read_buf);
|
|
kfree(ldata->echo_buf);
|
|
kfree(ldata);
|
|
tty->disc_data = NULL;
|
|
}
|
|
|
|
/**
|
|
* n_tty_open - open an ldisc
|
|
* @tty: terminal to open
|
|
*
|
|
* Called when this line discipline is being attached to the
|
|
* terminal device. Can sleep. Called serialized so that no
|
|
* other events will occur in parallel. No further open will occur
|
|
* until a close.
|
|
*/
|
|
|
|
static int n_tty_open(struct tty_struct *tty)
|
|
{
|
|
struct n_tty_data *ldata;
|
|
|
|
ldata = kzalloc(sizeof(*ldata), GFP_KERNEL);
|
|
if (!ldata)
|
|
goto err;
|
|
|
|
ldata->overrun_time = jiffies;
|
|
mutex_init(&ldata->atomic_read_lock);
|
|
mutex_init(&ldata->output_lock);
|
|
mutex_init(&ldata->echo_lock);
|
|
spin_lock_init(&ldata->read_lock);
|
|
|
|
/* These are ugly. Currently a malloc failure here can panic */
|
|
ldata->read_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL);
|
|
ldata->echo_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL);
|
|
if (!ldata->read_buf || !ldata->echo_buf)
|
|
goto err_free_bufs;
|
|
|
|
tty->disc_data = ldata;
|
|
reset_buffer_flags(tty);
|
|
tty_unthrottle(tty);
|
|
ldata->column = 0;
|
|
n_tty_set_termios(tty, NULL);
|
|
tty->minimum_to_wake = 1;
|
|
tty->closing = 0;
|
|
|
|
return 0;
|
|
err_free_bufs:
|
|
kfree(ldata->read_buf);
|
|
kfree(ldata->echo_buf);
|
|
kfree(ldata);
|
|
err:
|
|
return -ENOMEM;
|
|
}
|
|
|
|
static inline int input_available_p(struct tty_struct *tty, int amt)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
|
|
tty_flush_to_ldisc(tty);
|
|
if (ldata->icanon && !L_EXTPROC(tty)) {
|
|
if (ldata->canon_data)
|
|
return 1;
|
|
} else if (ldata->read_cnt >= (amt ? amt : 1))
|
|
return 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* copy_from_read_buf - copy read data directly
|
|
* @tty: terminal device
|
|
* @b: user data
|
|
* @nr: size of data
|
|
*
|
|
* 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 ldata->atomic_read_lock sem
|
|
*
|
|
*/
|
|
|
|
static int copy_from_read_buf(struct tty_struct *tty,
|
|
unsigned char __user **b,
|
|
size_t *nr)
|
|
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
int retval;
|
|
size_t n;
|
|
unsigned long flags;
|
|
bool is_eof;
|
|
|
|
retval = 0;
|
|
spin_lock_irqsave(&ldata->read_lock, flags);
|
|
n = min(ldata->read_cnt, N_TTY_BUF_SIZE - ldata->read_tail);
|
|
n = min(*nr, n);
|
|
spin_unlock_irqrestore(&ldata->read_lock, flags);
|
|
if (n) {
|
|
retval = copy_to_user(*b, &ldata->read_buf[ldata->read_tail], n);
|
|
n -= retval;
|
|
is_eof = n == 1 &&
|
|
ldata->read_buf[ldata->read_tail] == EOF_CHAR(tty);
|
|
tty_audit_add_data(tty, &ldata->read_buf[ldata->read_tail], n,
|
|
ldata->icanon);
|
|
spin_lock_irqsave(&ldata->read_lock, flags);
|
|
ldata->read_tail = (ldata->read_tail + n) & (N_TTY_BUF_SIZE-1);
|
|
ldata->read_cnt -= n;
|
|
/* Turn single EOF into zero-length read */
|
|
if (L_EXTPROC(tty) && ldata->icanon && is_eof && !ldata->read_cnt)
|
|
n = 0;
|
|
spin_unlock_irqrestore(&ldata->read_lock, flags);
|
|
*b += n;
|
|
*nr -= n;
|
|
}
|
|
return retval;
|
|
}
|
|
|
|
extern ssize_t redirected_tty_write(struct file *, const char __user *,
|
|
size_t, loff_t *);
|
|
|
|
/**
|
|
* job_control - check job control
|
|
* @tty: tty
|
|
* @file: file handle
|
|
*
|
|
* Perform job control management checks on this file/tty descriptor
|
|
* and if appropriate send any needed signals and return a negative
|
|
* error code if action should be taken.
|
|
*
|
|
* 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
|
|
every sleep (POSIX.1 7.1.1.4). */
|
|
/* 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;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
|
|
/**
|
|
* n_tty_read - read function for tty
|
|
* @tty: tty device
|
|
* @file: file object
|
|
* @buf: userspace buffer pointer
|
|
* @nr: size of I/O
|
|
*
|
|
* Perform reads for the line discipline. We are guaranteed that the
|
|
* line discipline will not be closed under us but we may get multiple
|
|
* parallel readers and must handle this ourselves. We may also get
|
|
* a hangup. Always called in user context, may sleep.
|
|
*
|
|
* This code must be sure never to sleep through a hangup.
|
|
*/
|
|
|
|
static ssize_t 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:
|
|
c = job_control(tty, file);
|
|
if (c < 0)
|
|
return c;
|
|
|
|
minimum = time = 0;
|
|
timeout = MAX_SCHEDULE_TIMEOUT;
|
|
if (!ldata->icanon) {
|
|
time = (HZ / 10) * TIME_CHAR(tty);
|
|
minimum = MIN_CHAR(tty);
|
|
if (minimum) {
|
|
if (time)
|
|
tty->minimum_to_wake = 1;
|
|
else if (!waitqueue_active(&tty->read_wait) ||
|
|
(tty->minimum_to_wake > minimum))
|
|
tty->minimum_to_wake = minimum;
|
|
} else {
|
|
timeout = 0;
|
|
if (time) {
|
|
timeout = time;
|
|
time = 0;
|
|
}
|
|
tty->minimum_to_wake = minimum = 1;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
}
|
|
packet = tty->packet;
|
|
|
|
add_wait_queue(&tty->read_wait, &wait);
|
|
while (nr) {
|
|
/* First test for status change. */
|
|
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;
|
|
spin_unlock_irqrestore(&tty->link->ctrl_lock, flags);
|
|
if (tty_put_user(tty, cs, b++)) {
|
|
retval = -EFAULT;
|
|
b--;
|
|
break;
|
|
}
|
|
nr--;
|
|
break;
|
|
}
|
|
/* This statement must be first before checking for input
|
|
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;
|
|
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;
|
|
}
|
|
/* FIXME: does n_tty_set_room need locking ? */
|
|
n_tty_set_room(tty);
|
|
timeout = schedule_timeout(timeout);
|
|
continue;
|
|
}
|
|
__set_current_state(TASK_RUNNING);
|
|
|
|
/* Deal with packet mode. */
|
|
if (packet && b == buf) {
|
|
if (tty_put_user(tty, TIOCPKT_DATA, b++)) {
|
|
retval = -EFAULT;
|
|
b--;
|
|
break;
|
|
}
|
|
nr--;
|
|
}
|
|
|
|
if (ldata->icanon && !L_EXTPROC(tty)) {
|
|
/* N.B. avoid overrun if nr == 0 */
|
|
spin_lock_irqsave(&ldata->read_lock, flags);
|
|
while (nr && ldata->read_cnt) {
|
|
int eol;
|
|
|
|
eol = test_and_clear_bit(ldata->read_tail,
|
|
ldata->read_flags);
|
|
c = ldata->read_buf[ldata->read_tail];
|
|
ldata->read_tail = ((ldata->read_tail+1) &
|
|
(N_TTY_BUF_SIZE-1));
|
|
ldata->read_cnt--;
|
|
if (eol) {
|
|
/* this test should be redundant:
|
|
* we shouldn't be reading data if
|
|
* canon_data is 0
|
|
*/
|
|
if (--ldata->canon_data < 0)
|
|
ldata->canon_data = 0;
|
|
}
|
|
spin_unlock_irqrestore(&ldata->read_lock, flags);
|
|
|
|
if (!eol || (c != __DISABLED_CHAR)) {
|
|
if (tty_put_user(tty, c, b++)) {
|
|
retval = -EFAULT;
|
|
b--;
|
|
spin_lock_irqsave(&ldata->read_lock, flags);
|
|
break;
|
|
}
|
|
nr--;
|
|
}
|
|
if (eol) {
|
|
tty_audit_push(tty);
|
|
spin_lock_irqsave(&ldata->read_lock, flags);
|
|
break;
|
|
}
|
|
spin_lock_irqsave(&ldata->read_lock, flags);
|
|
}
|
|
spin_unlock_irqrestore(&ldata->read_lock, flags);
|
|
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) {
|
|
retval = -EFAULT;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* 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);
|
|
}
|
|
|
|
if (b - buf >= minimum)
|
|
break;
|
|
if (time)
|
|
timeout = time;
|
|
}
|
|
mutex_unlock(&ldata->atomic_read_lock);
|
|
remove_wait_queue(&tty->read_wait, &wait);
|
|
|
|
if (!waitqueue_active(&tty->read_wait))
|
|
tty->minimum_to_wake = minimum;
|
|
|
|
__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;
|
|
|
|
n_tty_set_room(tty);
|
|
return retval;
|
|
}
|
|
|
|
/**
|
|
* 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
|
|
* respect to other write callers but not to termios changes, reads
|
|
* 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 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);
|
|
int c;
|
|
ssize_t retval = 0;
|
|
|
|
/* Job control check -- must be done at start (POSIX.1 7.1.1.4). */
|
|
if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) {
|
|
retval = tty_check_change(tty);
|
|
if (retval)
|
|
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 (signal_pending(current)) {
|
|
retval = -ERESTARTSYS;
|
|
break;
|
|
}
|
|
if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) {
|
|
retval = -EIO;
|
|
break;
|
|
}
|
|
if (O_OPOST(tty) && !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) {
|
|
while (nr > 0) {
|
|
ssize_t num = process_output_block(tty, b, nr);
|
|
if (num < 0) {
|
|
if (num == -EAGAIN)
|
|
break;
|
|
retval = num;
|
|
goto break_out;
|
|
}
|
|
b += num;
|
|
nr -= num;
|
|
if (nr == 0)
|
|
break;
|
|
c = *b;
|
|
if (process_output(c, tty) < 0)
|
|
break;
|
|
b++; nr--;
|
|
}
|
|
if (tty->ops->flush_chars)
|
|
tty->ops->flush_chars(tty);
|
|
} else {
|
|
while (nr > 0) {
|
|
c = tty->ops->write(tty, b, nr);
|
|
if (c < 0) {
|
|
retval = c;
|
|
goto break_out;
|
|
}
|
|
if (!c)
|
|
break;
|
|
b += c;
|
|
nr -= c;
|
|
}
|
|
}
|
|
if (!nr)
|
|
break;
|
|
if (file->f_flags & O_NONBLOCK) {
|
|
retval = -EAGAIN;
|
|
break;
|
|
}
|
|
schedule();
|
|
}
|
|
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;
|
|
}
|
|
|
|
/**
|
|
* n_tty_poll - poll method for N_TTY
|
|
* @tty: terminal device
|
|
* @file: file accessing it
|
|
* @wait: poll table
|
|
*
|
|
* Called when the line discipline is asked to poll() for data or
|
|
* for special events. This code is not serialized with respect to
|
|
* other events save open/close.
|
|
*
|
|
* This code must be sure never to sleep through a hangup.
|
|
* Called without the kernel lock held - fine
|
|
*/
|
|
|
|
static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file,
|
|
poll_table *wait)
|
|
{
|
|
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)))
|
|
mask |= POLLIN | POLLRDNORM;
|
|
if (tty->packet && tty->link->ctrl_status)
|
|
mask |= POLLPRI | POLLIN | POLLRDNORM;
|
|
if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
|
|
mask |= POLLHUP;
|
|
if (tty_hung_up_p(file))
|
|
mask |= POLLHUP;
|
|
if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) {
|
|
if (MIN_CHAR(tty) && !TIME_CHAR(tty))
|
|
tty->minimum_to_wake = MIN_CHAR(tty);
|
|
else
|
|
tty->minimum_to_wake = 1;
|
|
}
|
|
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;
|
|
}
|
|
|
|
static unsigned long inq_canon(struct n_tty_data *ldata)
|
|
{
|
|
int nr, head, tail;
|
|
|
|
if (!ldata->canon_data)
|
|
return 0;
|
|
head = ldata->canon_head;
|
|
tail = ldata->read_tail;
|
|
nr = (head - tail) & (N_TTY_BUF_SIZE-1);
|
|
/* Skip EOF-chars.. */
|
|
while (head != tail) {
|
|
if (test_bit(tail, ldata->read_flags) &&
|
|
ldata->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)
|
|
{
|
|
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 = ldata->read_cnt;
|
|
if (L_ICANON(tty))
|
|
retval = inq_canon(ldata);
|
|
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);
|