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62 |
marcus.erl |
/*
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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 write_chan 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 <asm/uaccess.h>
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#include <asm/system.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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static inline unsigned char *alloc_buf(void)
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{
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gfp_t prio = in_interrupt() ? GFP_ATOMIC : GFP_KERNEL;
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if (PAGE_SIZE != N_TTY_BUF_SIZE)
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return kmalloc(N_TTY_BUF_SIZE, prio);
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else
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return (unsigned char *)__get_free_page(prio);
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}
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static inline void free_buf(unsigned char *buf)
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{
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if (PAGE_SIZE != N_TTY_BUF_SIZE)
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kfree(buf);
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else
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free_page((unsigned long) buf);
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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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tty_audit_add_data(tty, &x, 1);
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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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int left = N_TTY_BUF_SIZE - tty->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 = tty->icanon && !tty->canon_data;
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tty->receive_room = left;
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}
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static void put_tty_queue_nolock(unsigned char c, struct tty_struct *tty)
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{
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if (tty->read_cnt < N_TTY_BUF_SIZE) {
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tty->read_buf[tty->read_head] = c;
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tty->read_head = (tty->read_head + 1) & (N_TTY_BUF_SIZE-1);
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tty->read_cnt++;
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}
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}
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static void put_tty_queue(unsigned char c, struct tty_struct *tty)
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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(&tty->read_lock, flags);
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put_tty_queue_nolock(c, tty);
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spin_unlock_irqrestore(&tty->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 function.
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* We test the TTY_THROTTLED bit first so that it always
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* indicates the current state. The decision about whether
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* it is worth allowing more input has been taken by the caller.
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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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test_and_clear_bit(TTY_THROTTLED, &tty->flags) &&
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tty->driver->unthrottle)
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tty->driver->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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static void reset_buffer_flags(struct tty_struct *tty)
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{
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unsigned long flags;
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spin_lock_irqsave(&tty->read_lock, flags);
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tty->read_head = tty->read_tail = tty->read_cnt = 0;
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spin_unlock_irqrestore(&tty->read_lock, flags);
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tty->canon_head = tty->canon_data = tty->erasing = 0;
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memset(&tty->read_flags, 0, sizeof tty->read_flags);
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n_tty_set_room(tty);
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check_unthrottle(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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* FIXME: tty->ctrl_status is not spinlocked and relies on
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* lock_kernel() still.
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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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/* 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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| 198 |
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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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}
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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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| 212 |
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static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty)
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{
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unsigned long flags;
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ssize_t n = 0;
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spin_lock_irqsave(&tty->read_lock, flags);
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if (!tty->icanon) {
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n = tty->read_cnt;
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} else if (tty->canon_data) {
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n = (tty->canon_head > tty->read_tail) ?
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tty->canon_head - tty->read_tail :
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tty->canon_head + (N_TTY_BUF_SIZE - tty->read_tail);
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}
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spin_unlock_irqrestore(&tty->read_lock, flags);
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return n;
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}
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| 229 |
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/**
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| 230 |
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* is_utf8_continuation - utf8 multibyte check
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* @c: byte to check
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| 232 |
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*
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| 233 |
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* Returns true if the utf8 character 'c' is a multibyte continuation
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| 234 |
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* character. We use this to correctly compute the on screen size
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| 235 |
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* of the character when printing
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*/
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| 237 |
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| 238 |
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static inline int is_utf8_continuation(unsigned char c)
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| 239 |
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{
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| 240 |
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return (c & 0xc0) == 0x80;
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| 241 |
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}
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| 242 |
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| 243 |
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/**
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| 244 |
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* is_continuation - multibyte check
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| 245 |
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* @c: byte to check
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| 246 |
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*
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| 247 |
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* Returns true if the utf8 character 'c' is a multibyte continuation
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| 248 |
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* character and the terminal is in unicode mode.
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| 249 |
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*/
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| 250 |
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| 251 |
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static inline int is_continuation(unsigned char c, struct tty_struct *tty)
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| 252 |
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{
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| 253 |
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return I_IUTF8(tty) && is_utf8_continuation(c);
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| 254 |
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}
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| 255 |
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| 256 |
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/**
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| 257 |
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* opost - output post processor
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| 258 |
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* @c: character (or partial unicode symbol)
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| 259 |
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* @tty: terminal device
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| 260 |
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*
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| 261 |
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* Perform OPOST processing. Returns -1 when the output device is
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| 262 |
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* full and the character must be retried. Note that Linux currently
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| 263 |
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* ignores TABDLY, CRDLY, VTDLY, FFDLY and NLDLY. They simply aren't
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| 264 |
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* relevant in the world today. If you ever need them, add them here.
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| 265 |
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*
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| 266 |
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* Called from both the receive and transmit sides and can be called
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| 267 |
|
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* re-entrantly. Relies on lock_kernel() still.
|
| 268 |
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*/
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| 269 |
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|
| 270 |
|
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static int opost(unsigned char c, struct tty_struct *tty)
|
| 271 |
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{
|
| 272 |
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int space, spaces;
|
| 273 |
|
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|
| 274 |
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space = tty->driver->write_room(tty);
|
| 275 |
|
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if (!space)
|
| 276 |
|
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return -1;
|
| 277 |
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|
|
| 278 |
|
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if (O_OPOST(tty)) {
|
| 279 |
|
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switch (c) {
|
| 280 |
|
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case '\n':
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| 281 |
|
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if (O_ONLRET(tty))
|
| 282 |
|
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tty->column = 0;
|
| 283 |
|
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if (O_ONLCR(tty)) {
|
| 284 |
|
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if (space < 2)
|
| 285 |
|
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return -1;
|
| 286 |
|
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tty->driver->put_char(tty, '\r');
|
| 287 |
|
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tty->column = 0;
|
| 288 |
|
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}
|
| 289 |
|
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tty->canon_column = tty->column;
|
| 290 |
|
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break;
|
| 291 |
|
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case '\r':
|
| 292 |
|
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if (O_ONOCR(tty) && tty->column == 0)
|
| 293 |
|
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return 0;
|
| 294 |
|
|
if (O_OCRNL(tty)) {
|
| 295 |
|
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c = '\n';
|
| 296 |
|
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if (O_ONLRET(tty))
|
| 297 |
|
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tty->canon_column = tty->column = 0;
|
| 298 |
|
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break;
|
| 299 |
|
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}
|
| 300 |
|
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tty->canon_column = tty->column = 0;
|
| 301 |
|
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break;
|
| 302 |
|
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case '\t':
|
| 303 |
|
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spaces = 8 - (tty->column & 7);
|
| 304 |
|
|
if (O_TABDLY(tty) == XTABS) {
|
| 305 |
|
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if (space < spaces)
|
| 306 |
|
|
return -1;
|
| 307 |
|
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tty->column += spaces;
|
| 308 |
|
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tty->driver->write(tty, " ", spaces);
|
| 309 |
|
|
return 0;
|
| 310 |
|
|
}
|
| 311 |
|
|
tty->column += spaces;
|
| 312 |
|
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break;
|
| 313 |
|
|
case '\b':
|
| 314 |
|
|
if (tty->column > 0)
|
| 315 |
|
|
tty->column--;
|
| 316 |
|
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break;
|
| 317 |
|
|
default:
|
| 318 |
|
|
if (O_OLCUC(tty))
|
| 319 |
|
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c = toupper(c);
|
| 320 |
|
|
if (!iscntrl(c) && !is_continuation(c, tty))
|
| 321 |
|
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tty->column++;
|
| 322 |
|
|
break;
|
| 323 |
|
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}
|
| 324 |
|
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}
|
| 325 |
|
|
tty->driver->put_char(tty, c);
|
| 326 |
|
|
return 0;
|
| 327 |
|
|
}
|
| 328 |
|
|
|
| 329 |
|
|
/**
|
| 330 |
|
|
* opost_block - block postprocess
|
| 331 |
|
|
* @tty: terminal device
|
| 332 |
|
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* @inbuf: user buffer
|
| 333 |
|
|
* @nr: number of bytes
|
| 334 |
|
|
*
|
| 335 |
|
|
* This path is used to speed up block console writes, among other
|
| 336 |
|
|
* things when processing blocks of output data. It handles only
|
| 337 |
|
|
* the simple cases normally found and helps to generate blocks of
|
| 338 |
|
|
* symbols for the console driver and thus improve performance.
|
| 339 |
|
|
*
|
| 340 |
|
|
* Called from write_chan under the tty layer write lock.
|
| 341 |
|
|
*/
|
| 342 |
|
|
|
| 343 |
|
|
static ssize_t opost_block(struct tty_struct * tty,
|
| 344 |
|
|
const unsigned char * buf, unsigned int nr)
|
| 345 |
|
|
{
|
| 346 |
|
|
int space;
|
| 347 |
|
|
int i;
|
| 348 |
|
|
const unsigned char *cp;
|
| 349 |
|
|
|
| 350 |
|
|
space = tty->driver->write_room(tty);
|
| 351 |
|
|
if (!space)
|
| 352 |
|
|
return 0;
|
| 353 |
|
|
if (nr > space)
|
| 354 |
|
|
nr = space;
|
| 355 |
|
|
|
| 356 |
|
|
for (i = 0, cp = buf; i < nr; i++, cp++) {
|
| 357 |
|
|
switch (*cp) {
|
| 358 |
|
|
case '\n':
|
| 359 |
|
|
if (O_ONLRET(tty))
|
| 360 |
|
|
tty->column = 0;
|
| 361 |
|
|
if (O_ONLCR(tty))
|
| 362 |
|
|
goto break_out;
|
| 363 |
|
|
tty->canon_column = tty->column;
|
| 364 |
|
|
break;
|
| 365 |
|
|
case '\r':
|
| 366 |
|
|
if (O_ONOCR(tty) && tty->column == 0)
|
| 367 |
|
|
goto break_out;
|
| 368 |
|
|
if (O_OCRNL(tty))
|
| 369 |
|
|
goto break_out;
|
| 370 |
|
|
tty->canon_column = tty->column = 0;
|
| 371 |
|
|
break;
|
| 372 |
|
|
case '\t':
|
| 373 |
|
|
goto break_out;
|
| 374 |
|
|
case '\b':
|
| 375 |
|
|
if (tty->column > 0)
|
| 376 |
|
|
tty->column--;
|
| 377 |
|
|
break;
|
| 378 |
|
|
default:
|
| 379 |
|
|
if (O_OLCUC(tty))
|
| 380 |
|
|
goto break_out;
|
| 381 |
|
|
if (!iscntrl(*cp))
|
| 382 |
|
|
tty->column++;
|
| 383 |
|
|
break;
|
| 384 |
|
|
}
|
| 385 |
|
|
}
|
| 386 |
|
|
break_out:
|
| 387 |
|
|
if (tty->driver->flush_chars)
|
| 388 |
|
|
tty->driver->flush_chars(tty);
|
| 389 |
|
|
i = tty->driver->write(tty, buf, i);
|
| 390 |
|
|
return i;
|
| 391 |
|
|
}
|
| 392 |
|
|
|
| 393 |
|
|
|
| 394 |
|
|
/**
|
| 395 |
|
|
* put_char - write character to driver
|
| 396 |
|
|
* @c: character (or part of unicode symbol)
|
| 397 |
|
|
* @tty: terminal device
|
| 398 |
|
|
*
|
| 399 |
|
|
* Queue a byte to the driver layer for output
|
| 400 |
|
|
*/
|
| 401 |
|
|
|
| 402 |
|
|
static inline void put_char(unsigned char c, struct tty_struct *tty)
|
| 403 |
|
|
{
|
| 404 |
|
|
tty->driver->put_char(tty, c);
|
| 405 |
|
|
}
|
| 406 |
|
|
|
| 407 |
|
|
/**
|
| 408 |
|
|
* echo_char - echo characters
|
| 409 |
|
|
* @c: unicode byte to echo
|
| 410 |
|
|
* @tty: terminal device
|
| 411 |
|
|
*
|
| 412 |
|
|
* Echo user input back onto the screen. This must be called only when
|
| 413 |
|
|
* L_ECHO(tty) is true. Called from the driver receive_buf path.
|
| 414 |
|
|
*/
|
| 415 |
|
|
|
| 416 |
|
|
static void echo_char(unsigned char c, struct tty_struct *tty)
|
| 417 |
|
|
{
|
| 418 |
|
|
if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') {
|
| 419 |
|
|
put_char('^', tty);
|
| 420 |
|
|
put_char(c ^ 0100, tty);
|
| 421 |
|
|
tty->column += 2;
|
| 422 |
|
|
} else
|
| 423 |
|
|
opost(c, tty);
|
| 424 |
|
|
}
|
| 425 |
|
|
|
| 426 |
|
|
static inline void finish_erasing(struct tty_struct *tty)
|
| 427 |
|
|
{
|
| 428 |
|
|
if (tty->erasing) {
|
| 429 |
|
|
put_char('/', tty);
|
| 430 |
|
|
tty->column++;
|
| 431 |
|
|
tty->erasing = 0;
|
| 432 |
|
|
}
|
| 433 |
|
|
}
|
| 434 |
|
|
|
| 435 |
|
|
/**
|
| 436 |
|
|
* eraser - handle erase function
|
| 437 |
|
|
* @c: character input
|
| 438 |
|
|
* @tty: terminal device
|
| 439 |
|
|
*
|
| 440 |
|
|
* Perform erase and necessary output when an erase character is
|
| 441 |
|
|
* present in the stream from the driver layer. Handles the complexities
|
| 442 |
|
|
* of UTF-8 multibyte symbols.
|
| 443 |
|
|
*/
|
| 444 |
|
|
|
| 445 |
|
|
static void eraser(unsigned char c, struct tty_struct *tty)
|
| 446 |
|
|
{
|
| 447 |
|
|
enum { ERASE, WERASE, KILL } kill_type;
|
| 448 |
|
|
int head, seen_alnums, cnt;
|
| 449 |
|
|
unsigned long flags;
|
| 450 |
|
|
|
| 451 |
|
|
if (tty->read_head == tty->canon_head) {
|
| 452 |
|
|
/* opost('\a', tty); */ /* what do you think? */
|
| 453 |
|
|
return;
|
| 454 |
|
|
}
|
| 455 |
|
|
if (c == ERASE_CHAR(tty))
|
| 456 |
|
|
kill_type = ERASE;
|
| 457 |
|
|
else if (c == WERASE_CHAR(tty))
|
| 458 |
|
|
kill_type = WERASE;
|
| 459 |
|
|
else {
|
| 460 |
|
|
if (!L_ECHO(tty)) {
|
| 461 |
|
|
spin_lock_irqsave(&tty->read_lock, flags);
|
| 462 |
|
|
tty->read_cnt -= ((tty->read_head - tty->canon_head) &
|
| 463 |
|
|
(N_TTY_BUF_SIZE - 1));
|
| 464 |
|
|
tty->read_head = tty->canon_head;
|
| 465 |
|
|
spin_unlock_irqrestore(&tty->read_lock, flags);
|
| 466 |
|
|
return;
|
| 467 |
|
|
}
|
| 468 |
|
|
if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) {
|
| 469 |
|
|
spin_lock_irqsave(&tty->read_lock, flags);
|
| 470 |
|
|
tty->read_cnt -= ((tty->read_head - tty->canon_head) &
|
| 471 |
|
|
(N_TTY_BUF_SIZE - 1));
|
| 472 |
|
|
tty->read_head = tty->canon_head;
|
| 473 |
|
|
spin_unlock_irqrestore(&tty->read_lock, flags);
|
| 474 |
|
|
finish_erasing(tty);
|
| 475 |
|
|
echo_char(KILL_CHAR(tty), tty);
|
| 476 |
|
|
/* Add a newline if ECHOK is on and ECHOKE is off. */
|
| 477 |
|
|
if (L_ECHOK(tty))
|
| 478 |
|
|
opost('\n', tty);
|
| 479 |
|
|
return;
|
| 480 |
|
|
}
|
| 481 |
|
|
kill_type = KILL;
|
| 482 |
|
|
}
|
| 483 |
|
|
|
| 484 |
|
|
seen_alnums = 0;
|
| 485 |
|
|
while (tty->read_head != tty->canon_head) {
|
| 486 |
|
|
head = tty->read_head;
|
| 487 |
|
|
|
| 488 |
|
|
/* erase a single possibly multibyte character */
|
| 489 |
|
|
do {
|
| 490 |
|
|
head = (head - 1) & (N_TTY_BUF_SIZE-1);
|
| 491 |
|
|
c = tty->read_buf[head];
|
| 492 |
|
|
} while (is_continuation(c, tty) && head != tty->canon_head);
|
| 493 |
|
|
|
| 494 |
|
|
/* do not partially erase */
|
| 495 |
|
|
if (is_continuation(c, tty))
|
| 496 |
|
|
break;
|
| 497 |
|
|
|
| 498 |
|
|
if (kill_type == WERASE) {
|
| 499 |
|
|
/* Equivalent to BSD's ALTWERASE. */
|
| 500 |
|
|
if (isalnum(c) || c == '_')
|
| 501 |
|
|
seen_alnums++;
|
| 502 |
|
|
else if (seen_alnums)
|
| 503 |
|
|
break;
|
| 504 |
|
|
}
|
| 505 |
|
|
cnt = (tty->read_head - head) & (N_TTY_BUF_SIZE-1);
|
| 506 |
|
|
spin_lock_irqsave(&tty->read_lock, flags);
|
| 507 |
|
|
tty->read_head = head;
|
| 508 |
|
|
tty->read_cnt -= cnt;
|
| 509 |
|
|
spin_unlock_irqrestore(&tty->read_lock, flags);
|
| 510 |
|
|
if (L_ECHO(tty)) {
|
| 511 |
|
|
if (L_ECHOPRT(tty)) {
|
| 512 |
|
|
if (!tty->erasing) {
|
| 513 |
|
|
put_char('\\', tty);
|
| 514 |
|
|
tty->column++;
|
| 515 |
|
|
tty->erasing = 1;
|
| 516 |
|
|
}
|
| 517 |
|
|
/* if cnt > 1, output a multi-byte character */
|
| 518 |
|
|
echo_char(c, tty);
|
| 519 |
|
|
while (--cnt > 0) {
|
| 520 |
|
|
head = (head+1) & (N_TTY_BUF_SIZE-1);
|
| 521 |
|
|
put_char(tty->read_buf[head], tty);
|
| 522 |
|
|
}
|
| 523 |
|
|
} else if (kill_type == ERASE && !L_ECHOE(tty)) {
|
| 524 |
|
|
echo_char(ERASE_CHAR(tty), tty);
|
| 525 |
|
|
} else if (c == '\t') {
|
| 526 |
|
|
unsigned int col = tty->canon_column;
|
| 527 |
|
|
unsigned long tail = tty->canon_head;
|
| 528 |
|
|
|
| 529 |
|
|
/* Find the column of the last char. */
|
| 530 |
|
|
while (tail != tty->read_head) {
|
| 531 |
|
|
c = tty->read_buf[tail];
|
| 532 |
|
|
if (c == '\t')
|
| 533 |
|
|
col = (col | 7) + 1;
|
| 534 |
|
|
else if (iscntrl(c)) {
|
| 535 |
|
|
if (L_ECHOCTL(tty))
|
| 536 |
|
|
col += 2;
|
| 537 |
|
|
} else if (!is_continuation(c, tty))
|
| 538 |
|
|
col++;
|
| 539 |
|
|
tail = (tail+1) & (N_TTY_BUF_SIZE-1);
|
| 540 |
|
|
}
|
| 541 |
|
|
|
| 542 |
|
|
/* should never happen */
|
| 543 |
|
|
if (tty->column > 0x80000000)
|
| 544 |
|
|
tty->column = 0;
|
| 545 |
|
|
|
| 546 |
|
|
/* Now backup to that column. */
|
| 547 |
|
|
while (tty->column > col) {
|
| 548 |
|
|
/* Can't use opost here. */
|
| 549 |
|
|
put_char('\b', tty);
|
| 550 |
|
|
if (tty->column > 0)
|
| 551 |
|
|
tty->column--;
|
| 552 |
|
|
}
|
| 553 |
|
|
} else {
|
| 554 |
|
|
if (iscntrl(c) && L_ECHOCTL(tty)) {
|
| 555 |
|
|
put_char('\b', tty);
|
| 556 |
|
|
put_char(' ', tty);
|
| 557 |
|
|
put_char('\b', tty);
|
| 558 |
|
|
if (tty->column > 0)
|
| 559 |
|
|
tty->column--;
|
| 560 |
|
|
}
|
| 561 |
|
|
if (!iscntrl(c) || L_ECHOCTL(tty)) {
|
| 562 |
|
|
put_char('\b', tty);
|
| 563 |
|
|
put_char(' ', tty);
|
| 564 |
|
|
put_char('\b', tty);
|
| 565 |
|
|
if (tty->column > 0)
|
| 566 |
|
|
tty->column--;
|
| 567 |
|
|
}
|
| 568 |
|
|
}
|
| 569 |
|
|
}
|
| 570 |
|
|
if (kill_type == ERASE)
|
| 571 |
|
|
break;
|
| 572 |
|
|
}
|
| 573 |
|
|
if (tty->read_head == tty->canon_head)
|
| 574 |
|
|
finish_erasing(tty);
|
| 575 |
|
|
}
|
| 576 |
|
|
|
| 577 |
|
|
/**
|
| 578 |
|
|
* isig - handle the ISIG optio
|
| 579 |
|
|
* @sig: signal
|
| 580 |
|
|
* @tty: terminal
|
| 581 |
|
|
* @flush: force flush
|
| 582 |
|
|
*
|
| 583 |
|
|
* Called when a signal is being sent due to terminal input. This
|
| 584 |
|
|
* may caus terminal flushing to take place according to the termios
|
| 585 |
|
|
* settings and character used. Called from the driver receive_buf
|
| 586 |
|
|
* path so serialized.
|
| 587 |
|
|
*/
|
| 588 |
|
|
|
| 589 |
|
|
static inline void isig(int sig, struct tty_struct *tty, int flush)
|
| 590 |
|
|
{
|
| 591 |
|
|
if (tty->pgrp)
|
| 592 |
|
|
kill_pgrp(tty->pgrp, sig, 1);
|
| 593 |
|
|
if (flush || !L_NOFLSH(tty)) {
|
| 594 |
|
|
n_tty_flush_buffer(tty);
|
| 595 |
|
|
if (tty->driver->flush_buffer)
|
| 596 |
|
|
tty->driver->flush_buffer(tty);
|
| 597 |
|
|
}
|
| 598 |
|
|
}
|
| 599 |
|
|
|
| 600 |
|
|
/**
|
| 601 |
|
|
* n_tty_receive_break - handle break
|
| 602 |
|
|
* @tty: terminal
|
| 603 |
|
|
*
|
| 604 |
|
|
* An RS232 break event has been hit in the incoming bitstream. This
|
| 605 |
|
|
* can cause a variety of events depending upon the termios settings.
|
| 606 |
|
|
*
|
| 607 |
|
|
* Called from the receive_buf path so single threaded.
|
| 608 |
|
|
*/
|
| 609 |
|
|
|
| 610 |
|
|
static inline void n_tty_receive_break(struct tty_struct *tty)
|
| 611 |
|
|
{
|
| 612 |
|
|
if (I_IGNBRK(tty))
|
| 613 |
|
|
return;
|
| 614 |
|
|
if (I_BRKINT(tty)) {
|
| 615 |
|
|
isig(SIGINT, tty, 1);
|
| 616 |
|
|
return;
|
| 617 |
|
|
}
|
| 618 |
|
|
if (I_PARMRK(tty)) {
|
| 619 |
|
|
put_tty_queue('\377', tty);
|
| 620 |
|
|
put_tty_queue('\0', tty);
|
| 621 |
|
|
}
|
| 622 |
|
|
put_tty_queue('\0', tty);
|
| 623 |
|
|
wake_up_interruptible(&tty->read_wait);
|
| 624 |
|
|
}
|
| 625 |
|
|
|
| 626 |
|
|
/**
|
| 627 |
|
|
* n_tty_receive_overrun - handle overrun reporting
|
| 628 |
|
|
* @tty: terminal
|
| 629 |
|
|
*
|
| 630 |
|
|
* Data arrived faster than we could process it. While the tty
|
| 631 |
|
|
* driver has flagged this the bits that were missed are gone
|
| 632 |
|
|
* forever.
|
| 633 |
|
|
*
|
| 634 |
|
|
* Called from the receive_buf path so single threaded. Does not
|
| 635 |
|
|
* need locking as num_overrun and overrun_time are function
|
| 636 |
|
|
* private.
|
| 637 |
|
|
*/
|
| 638 |
|
|
|
| 639 |
|
|
static inline void n_tty_receive_overrun(struct tty_struct *tty)
|
| 640 |
|
|
{
|
| 641 |
|
|
char buf[64];
|
| 642 |
|
|
|
| 643 |
|
|
tty->num_overrun++;
|
| 644 |
|
|
if (time_before(tty->overrun_time, jiffies - HZ) ||
|
| 645 |
|
|
time_after(tty->overrun_time, jiffies)) {
|
| 646 |
|
|
printk(KERN_WARNING "%s: %d input overrun(s)\n",
|
| 647 |
|
|
tty_name(tty, buf),
|
| 648 |
|
|
tty->num_overrun);
|
| 649 |
|
|
tty->overrun_time = jiffies;
|
| 650 |
|
|
tty->num_overrun = 0;
|
| 651 |
|
|
}
|
| 652 |
|
|
}
|
| 653 |
|
|
|
| 654 |
|
|
/**
|
| 655 |
|
|
* n_tty_receive_parity_error - error notifier
|
| 656 |
|
|
* @tty: terminal device
|
| 657 |
|
|
* @c: character
|
| 658 |
|
|
*
|
| 659 |
|
|
* Process a parity error and queue the right data to indicate
|
| 660 |
|
|
* the error case if necessary. Locking as per n_tty_receive_buf.
|
| 661 |
|
|
*/
|
| 662 |
|
|
static inline void n_tty_receive_parity_error(struct tty_struct *tty,
|
| 663 |
|
|
unsigned char c)
|
| 664 |
|
|
{
|
| 665 |
|
|
if (I_IGNPAR(tty)) {
|
| 666 |
|
|
return;
|
| 667 |
|
|
}
|
| 668 |
|
|
if (I_PARMRK(tty)) {
|
| 669 |
|
|
put_tty_queue('\377', tty);
|
| 670 |
|
|
put_tty_queue('\0', tty);
|
| 671 |
|
|
put_tty_queue(c, tty);
|
| 672 |
|
|
} else if (I_INPCK(tty))
|
| 673 |
|
|
put_tty_queue('\0', tty);
|
| 674 |
|
|
else
|
| 675 |
|
|
put_tty_queue(c, tty);
|
| 676 |
|
|
wake_up_interruptible(&tty->read_wait);
|
| 677 |
|
|
}
|
| 678 |
|
|
|
| 679 |
|
|
/**
|
| 680 |
|
|
* n_tty_receive_char - perform processing
|
| 681 |
|
|
* @tty: terminal device
|
| 682 |
|
|
* @c: character
|
| 683 |
|
|
*
|
| 684 |
|
|
* Process an individual character of input received from the driver.
|
| 685 |
|
|
* This is serialized with respect to itself by the rules for the
|
| 686 |
|
|
* driver above.
|
| 687 |
|
|
*/
|
| 688 |
|
|
|
| 689 |
|
|
static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
|
| 690 |
|
|
{
|
| 691 |
|
|
unsigned long flags;
|
| 692 |
|
|
|
| 693 |
|
|
if (tty->raw) {
|
| 694 |
|
|
put_tty_queue(c, tty);
|
| 695 |
|
|
return;
|
| 696 |
|
|
}
|
| 697 |
|
|
|
| 698 |
|
|
if (tty->stopped && !tty->flow_stopped &&
|
| 699 |
|
|
I_IXON(tty) && I_IXANY(tty)) {
|
| 700 |
|
|
start_tty(tty);
|
| 701 |
|
|
return;
|
| 702 |
|
|
}
|
| 703 |
|
|
|
| 704 |
|
|
if (I_ISTRIP(tty))
|
| 705 |
|
|
c &= 0x7f;
|
| 706 |
|
|
if (I_IUCLC(tty) && L_IEXTEN(tty))
|
| 707 |
|
|
c=tolower(c);
|
| 708 |
|
|
|
| 709 |
|
|
if (tty->closing) {
|
| 710 |
|
|
if (I_IXON(tty)) {
|
| 711 |
|
|
if (c == START_CHAR(tty))
|
| 712 |
|
|
start_tty(tty);
|
| 713 |
|
|
else if (c == STOP_CHAR(tty))
|
| 714 |
|
|
stop_tty(tty);
|
| 715 |
|
|
}
|
| 716 |
|
|
return;
|
| 717 |
|
|
}
|
| 718 |
|
|
|
| 719 |
|
|
/*
|
| 720 |
|
|
* If the previous character was LNEXT, or we know that this
|
| 721 |
|
|
* character is not one of the characters that we'll have to
|
| 722 |
|
|
* handle specially, do shortcut processing to speed things
|
| 723 |
|
|
* up.
|
| 724 |
|
|
*/
|
| 725 |
|
|
if (!test_bit(c, tty->process_char_map) || tty->lnext) {
|
| 726 |
|
|
finish_erasing(tty);
|
| 727 |
|
|
tty->lnext = 0;
|
| 728 |
|
|
if (L_ECHO(tty)) {
|
| 729 |
|
|
if (tty->read_cnt >= N_TTY_BUF_SIZE-1) {
|
| 730 |
|
|
put_char('\a', tty); /* beep if no space */
|
| 731 |
|
|
return;
|
| 732 |
|
|
}
|
| 733 |
|
|
/* Record the column of first canon char. */
|
| 734 |
|
|
if (tty->canon_head == tty->read_head)
|
| 735 |
|
|
tty->canon_column = tty->column;
|
| 736 |
|
|
echo_char(c, tty);
|
| 737 |
|
|
}
|
| 738 |
|
|
if (I_PARMRK(tty) && c == (unsigned char) '\377')
|
| 739 |
|
|
put_tty_queue(c, tty);
|
| 740 |
|
|
put_tty_queue(c, tty);
|
| 741 |
|
|
return;
|
| 742 |
|
|
}
|
| 743 |
|
|
|
| 744 |
|
|
if (c == '\r') {
|
| 745 |
|
|
if (I_IGNCR(tty))
|
| 746 |
|
|
return;
|
| 747 |
|
|
if (I_ICRNL(tty))
|
| 748 |
|
|
c = '\n';
|
| 749 |
|
|
} else if (c == '\n' && I_INLCR(tty))
|
| 750 |
|
|
c = '\r';
|
| 751 |
|
|
if (I_IXON(tty)) {
|
| 752 |
|
|
if (c == START_CHAR(tty)) {
|
| 753 |
|
|
start_tty(tty);
|
| 754 |
|
|
return;
|
| 755 |
|
|
}
|
| 756 |
|
|
if (c == STOP_CHAR(tty)) {
|
| 757 |
|
|
stop_tty(tty);
|
| 758 |
|
|
return;
|
| 759 |
|
|
}
|
| 760 |
|
|
}
|
| 761 |
|
|
if (L_ISIG(tty)) {
|
| 762 |
|
|
int signal;
|
| 763 |
|
|
signal = SIGINT;
|
| 764 |
|
|
if (c == INTR_CHAR(tty))
|
| 765 |
|
|
goto send_signal;
|
| 766 |
|
|
signal = SIGQUIT;
|
| 767 |
|
|
if (c == QUIT_CHAR(tty))
|
| 768 |
|
|
goto send_signal;
|
| 769 |
|
|
signal = SIGTSTP;
|
| 770 |
|
|
if (c == SUSP_CHAR(tty)) {
|
| 771 |
|
|
send_signal:
|
| 772 |
|
|
isig(signal, tty, 0);
|
| 773 |
|
|
return;
|
| 774 |
|
|
}
|
| 775 |
|
|
}
|
| 776 |
|
|
if (tty->icanon) {
|
| 777 |
|
|
if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) ||
|
| 778 |
|
|
(c == WERASE_CHAR(tty) && L_IEXTEN(tty))) {
|
| 779 |
|
|
eraser(c, tty);
|
| 780 |
|
|
return;
|
| 781 |
|
|
}
|
| 782 |
|
|
if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) {
|
| 783 |
|
|
tty->lnext = 1;
|
| 784 |
|
|
if (L_ECHO(tty)) {
|
| 785 |
|
|
finish_erasing(tty);
|
| 786 |
|
|
if (L_ECHOCTL(tty)) {
|
| 787 |
|
|
put_char('^', tty);
|
| 788 |
|
|
put_char('\b', tty);
|
| 789 |
|
|
}
|
| 790 |
|
|
}
|
| 791 |
|
|
return;
|
| 792 |
|
|
}
|
| 793 |
|
|
if (c == REPRINT_CHAR(tty) && L_ECHO(tty) &&
|
| 794 |
|
|
L_IEXTEN(tty)) {
|
| 795 |
|
|
unsigned long tail = tty->canon_head;
|
| 796 |
|
|
|
| 797 |
|
|
finish_erasing(tty);
|
| 798 |
|
|
echo_char(c, tty);
|
| 799 |
|
|
opost('\n', tty);
|
| 800 |
|
|
while (tail != tty->read_head) {
|
| 801 |
|
|
echo_char(tty->read_buf[tail], tty);
|
| 802 |
|
|
tail = (tail+1) & (N_TTY_BUF_SIZE-1);
|
| 803 |
|
|
}
|
| 804 |
|
|
return;
|
| 805 |
|
|
}
|
| 806 |
|
|
if (c == '\n') {
|
| 807 |
|
|
if (L_ECHO(tty) || L_ECHONL(tty)) {
|
| 808 |
|
|
if (tty->read_cnt >= N_TTY_BUF_SIZE-1)
|
| 809 |
|
|
put_char('\a', tty);
|
| 810 |
|
|
opost('\n', tty);
|
| 811 |
|
|
}
|
| 812 |
|
|
goto handle_newline;
|
| 813 |
|
|
}
|
| 814 |
|
|
if (c == EOF_CHAR(tty)) {
|
| 815 |
|
|
if (tty->canon_head != tty->read_head)
|
| 816 |
|
|
set_bit(TTY_PUSH, &tty->flags);
|
| 817 |
|
|
c = __DISABLED_CHAR;
|
| 818 |
|
|
goto handle_newline;
|
| 819 |
|
|
}
|
| 820 |
|
|
if ((c == EOL_CHAR(tty)) ||
|
| 821 |
|
|
(c == EOL2_CHAR(tty) && L_IEXTEN(tty))) {
|
| 822 |
|
|
/*
|
| 823 |
|
|
* XXX are EOL_CHAR and EOL2_CHAR echoed?!?
|
| 824 |
|
|
*/
|
| 825 |
|
|
if (L_ECHO(tty)) {
|
| 826 |
|
|
if (tty->read_cnt >= N_TTY_BUF_SIZE-1)
|
| 827 |
|
|
put_char('\a', tty);
|
| 828 |
|
|
/* Record the column of first canon char. */
|
| 829 |
|
|
if (tty->canon_head == tty->read_head)
|
| 830 |
|
|
tty->canon_column = tty->column;
|
| 831 |
|
|
echo_char(c, tty);
|
| 832 |
|
|
}
|
| 833 |
|
|
/*
|
| 834 |
|
|
* XXX does PARMRK doubling happen for
|
| 835 |
|
|
* EOL_CHAR and EOL2_CHAR?
|
| 836 |
|
|
*/
|
| 837 |
|
|
if (I_PARMRK(tty) && c == (unsigned char) '\377')
|
| 838 |
|
|
put_tty_queue(c, tty);
|
| 839 |
|
|
|
| 840 |
|
|
handle_newline:
|
| 841 |
|
|
spin_lock_irqsave(&tty->read_lock, flags);
|
| 842 |
|
|
set_bit(tty->read_head, tty->read_flags);
|
| 843 |
|
|
put_tty_queue_nolock(c, tty);
|
| 844 |
|
|
tty->canon_head = tty->read_head;
|
| 845 |
|
|
tty->canon_data++;
|
| 846 |
|
|
spin_unlock_irqrestore(&tty->read_lock, flags);
|
| 847 |
|
|
kill_fasync(&tty->fasync, SIGIO, POLL_IN);
|
| 848 |
|
|
if (waitqueue_active(&tty->read_wait))
|
| 849 |
|
|
wake_up_interruptible(&tty->read_wait);
|
| 850 |
|
|
return;
|
| 851 |
|
|
}
|
| 852 |
|
|
}
|
| 853 |
|
|
|
| 854 |
|
|
finish_erasing(tty);
|
| 855 |
|
|
if (L_ECHO(tty)) {
|
| 856 |
|
|
if (tty->read_cnt >= N_TTY_BUF_SIZE-1) {
|
| 857 |
|
|
put_char('\a', tty); /* beep if no space */
|
| 858 |
|
|
return;
|
| 859 |
|
|
}
|
| 860 |
|
|
if (c == '\n')
|
| 861 |
|
|
opost('\n', tty);
|
| 862 |
|
|
else {
|
| 863 |
|
|
/* Record the column of first canon char. */
|
| 864 |
|
|
if (tty->canon_head == tty->read_head)
|
| 865 |
|
|
tty->canon_column = tty->column;
|
| 866 |
|
|
echo_char(c, tty);
|
| 867 |
|
|
}
|
| 868 |
|
|
}
|
| 869 |
|
|
|
| 870 |
|
|
if (I_PARMRK(tty) && c == (unsigned char) '\377')
|
| 871 |
|
|
put_tty_queue(c, tty);
|
| 872 |
|
|
|
| 873 |
|
|
put_tty_queue(c, tty);
|
| 874 |
|
|
}
|
| 875 |
|
|
|
| 876 |
|
|
|
| 877 |
|
|
/**
|
| 878 |
|
|
* n_tty_write_wakeup - asynchronous I/O notifier
|
| 879 |
|
|
* @tty: tty device
|
| 880 |
|
|
*
|
| 881 |
|
|
* Required for the ptys, serial driver etc. since processes
|
| 882 |
|
|
* that attach themselves to the master and rely on ASYNC
|
| 883 |
|
|
* IO must be woken up
|
| 884 |
|
|
*/
|
| 885 |
|
|
|
| 886 |
|
|
static void n_tty_write_wakeup(struct tty_struct *tty)
|
| 887 |
|
|
{
|
| 888 |
|
|
if (tty->fasync)
|
| 889 |
|
|
{
|
| 890 |
|
|
set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
|
| 891 |
|
|
kill_fasync(&tty->fasync, SIGIO, POLL_OUT);
|
| 892 |
|
|
}
|
| 893 |
|
|
return;
|
| 894 |
|
|
}
|
| 895 |
|
|
|
| 896 |
|
|
/**
|
| 897 |
|
|
* n_tty_receive_buf - data receive
|
| 898 |
|
|
* @tty: terminal device
|
| 899 |
|
|
* @cp: buffer
|
| 900 |
|
|
* @fp: flag buffer
|
| 901 |
|
|
* @count: characters
|
| 902 |
|
|
*
|
| 903 |
|
|
* Called by the terminal driver when a block of characters has
|
| 904 |
|
|
* been received. This function must be called from soft contexts
|
| 905 |
|
|
* not from interrupt context. The driver is responsible for making
|
| 906 |
|
|
* calls one at a time and in order (or using flush_to_ldisc)
|
| 907 |
|
|
*/
|
| 908 |
|
|
|
| 909 |
|
|
static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
|
| 910 |
|
|
char *fp, int count)
|
| 911 |
|
|
{
|
| 912 |
|
|
const unsigned char *p;
|
| 913 |
|
|
char *f, flags = TTY_NORMAL;
|
| 914 |
|
|
int i;
|
| 915 |
|
|
char buf[64];
|
| 916 |
|
|
unsigned long cpuflags;
|
| 917 |
|
|
|
| 918 |
|
|
if (!tty->read_buf)
|
| 919 |
|
|
return;
|
| 920 |
|
|
|
| 921 |
|
|
if (tty->real_raw) {
|
| 922 |
|
|
spin_lock_irqsave(&tty->read_lock, cpuflags);
|
| 923 |
|
|
i = min(N_TTY_BUF_SIZE - tty->read_cnt,
|
| 924 |
|
|
N_TTY_BUF_SIZE - tty->read_head);
|
| 925 |
|
|
i = min(count, i);
|
| 926 |
|
|
memcpy(tty->read_buf + tty->read_head, cp, i);
|
| 927 |
|
|
tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1);
|
| 928 |
|
|
tty->read_cnt += i;
|
| 929 |
|
|
cp += i;
|
| 930 |
|
|
count -= i;
|
| 931 |
|
|
|
| 932 |
|
|
i = min(N_TTY_BUF_SIZE - tty->read_cnt,
|
| 933 |
|
|
N_TTY_BUF_SIZE - tty->read_head);
|
| 934 |
|
|
i = min(count, i);
|
| 935 |
|
|
memcpy(tty->read_buf + tty->read_head, cp, i);
|
| 936 |
|
|
tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1);
|
| 937 |
|
|
tty->read_cnt += i;
|
| 938 |
|
|
spin_unlock_irqrestore(&tty->read_lock, cpuflags);
|
| 939 |
|
|
} else {
|
| 940 |
|
|
for (i=count, p = cp, f = fp; i; i--, p++) {
|
| 941 |
|
|
if (f)
|
| 942 |
|
|
flags = *f++;
|
| 943 |
|
|
switch (flags) {
|
| 944 |
|
|
case TTY_NORMAL:
|
| 945 |
|
|
n_tty_receive_char(tty, *p);
|
| 946 |
|
|
break;
|
| 947 |
|
|
case TTY_BREAK:
|
| 948 |
|
|
n_tty_receive_break(tty);
|
| 949 |
|
|
break;
|
| 950 |
|
|
case TTY_PARITY:
|
| 951 |
|
|
case TTY_FRAME:
|
| 952 |
|
|
n_tty_receive_parity_error(tty, *p);
|
| 953 |
|
|
break;
|
| 954 |
|
|
case TTY_OVERRUN:
|
| 955 |
|
|
n_tty_receive_overrun(tty);
|
| 956 |
|
|
break;
|
| 957 |
|
|
default:
|
| 958 |
|
|
printk("%s: unknown flag %d\n",
|
| 959 |
|
|
tty_name(tty, buf), flags);
|
| 960 |
|
|
break;
|
| 961 |
|
|
}
|
| 962 |
|
|
}
|
| 963 |
|
|
if (tty->driver->flush_chars)
|
| 964 |
|
|
tty->driver->flush_chars(tty);
|
| 965 |
|
|
}
|
| 966 |
|
|
|
| 967 |
|
|
n_tty_set_room(tty);
|
| 968 |
|
|
|
| 969 |
|
|
if (!tty->icanon && (tty->read_cnt >= tty->minimum_to_wake)) {
|
| 970 |
|
|
kill_fasync(&tty->fasync, SIGIO, POLL_IN);
|
| 971 |
|
|
if (waitqueue_active(&tty->read_wait))
|
| 972 |
|
|
wake_up_interruptible(&tty->read_wait);
|
| 973 |
|
|
}
|
| 974 |
|
|
|
| 975 |
|
|
/*
|
| 976 |
|
|
* Check the remaining room for the input canonicalization
|
| 977 |
|
|
* mode. We don't want to throttle the driver if we're in
|
| 978 |
|
|
* canonical mode and don't have a newline yet!
|
| 979 |
|
|
*/
|
| 980 |
|
|
if (tty->receive_room < TTY_THRESHOLD_THROTTLE) {
|
| 981 |
|
|
/* check TTY_THROTTLED first so it indicates our state */
|
| 982 |
|
|
if (!test_and_set_bit(TTY_THROTTLED, &tty->flags) &&
|
| 983 |
|
|
tty->driver->throttle)
|
| 984 |
|
|
tty->driver->throttle(tty);
|
| 985 |
|
|
}
|
| 986 |
|
|
}
|
| 987 |
|
|
|
| 988 |
|
|
int is_ignored(int sig)
|
| 989 |
|
|
{
|
| 990 |
|
|
return (sigismember(¤t->blocked, sig) ||
|
| 991 |
|
|
current->sighand->action[sig-1].sa.sa_handler == SIG_IGN);
|
| 992 |
|
|
}
|
| 993 |
|
|
|
| 994 |
|
|
/**
|
| 995 |
|
|
* n_tty_set_termios - termios data changed
|
| 996 |
|
|
* @tty: terminal
|
| 997 |
|
|
* @old: previous data
|
| 998 |
|
|
*
|
| 999 |
|
|
* Called by the tty layer when the user changes termios flags so
|
| 1000 |
|
|
* that the line discipline can plan ahead. This function cannot sleep
|
| 1001 |
|
|
* and is protected from re-entry by the tty layer. The user is
|
| 1002 |
|
|
* guaranteed that this function will not be re-entered or in progress
|
| 1003 |
|
|
* when the ldisc is closed.
|
| 1004 |
|
|
*/
|
| 1005 |
|
|
|
| 1006 |
|
|
static void n_tty_set_termios(struct tty_struct *tty, struct ktermios * old)
|
| 1007 |
|
|
{
|
| 1008 |
|
|
if (!tty)
|
| 1009 |
|
|
return;
|
| 1010 |
|
|
|
| 1011 |
|
|
tty->icanon = (L_ICANON(tty) != 0);
|
| 1012 |
|
|
if (test_bit(TTY_HW_COOK_IN, &tty->flags)) {
|
| 1013 |
|
|
tty->raw = 1;
|
| 1014 |
|
|
tty->real_raw = 1;
|
| 1015 |
|
|
n_tty_set_room(tty);
|
| 1016 |
|
|
return;
|
| 1017 |
|
|
}
|
| 1018 |
|
|
if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) ||
|
| 1019 |
|
|
I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) ||
|
| 1020 |
|
|
I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) ||
|
| 1021 |
|
|
I_PARMRK(tty)) {
|
| 1022 |
|
|
memset(tty->process_char_map, 0, 256/8);
|
| 1023 |
|
|
|
| 1024 |
|
|
if (I_IGNCR(tty) || I_ICRNL(tty))
|
| 1025 |
|
|
set_bit('\r', tty->process_char_map);
|
| 1026 |
|
|
if (I_INLCR(tty))
|
| 1027 |
|
|
set_bit('\n', tty->process_char_map);
|
| 1028 |
|
|
|
| 1029 |
|
|
if (L_ICANON(tty)) {
|
| 1030 |
|
|
set_bit(ERASE_CHAR(tty), tty->process_char_map);
|
| 1031 |
|
|
set_bit(KILL_CHAR(tty), tty->process_char_map);
|
| 1032 |
|
|
set_bit(EOF_CHAR(tty), tty->process_char_map);
|
| 1033 |
|
|
set_bit('\n', tty->process_char_map);
|
| 1034 |
|
|
set_bit(EOL_CHAR(tty), tty->process_char_map);
|
| 1035 |
|
|
if (L_IEXTEN(tty)) {
|
| 1036 |
|
|
set_bit(WERASE_CHAR(tty),
|
| 1037 |
|
|
tty->process_char_map);
|
| 1038 |
|
|
set_bit(LNEXT_CHAR(tty),
|
| 1039 |
|
|
tty->process_char_map);
|
| 1040 |
|
|
set_bit(EOL2_CHAR(tty),
|
| 1041 |
|
|
tty->process_char_map);
|
| 1042 |
|
|
if (L_ECHO(tty))
|
| 1043 |
|
|
set_bit(REPRINT_CHAR(tty),
|
| 1044 |
|
|
tty->process_char_map);
|
| 1045 |
|
|
}
|
| 1046 |
|
|
}
|
| 1047 |
|
|
if (I_IXON(tty)) {
|
| 1048 |
|
|
set_bit(START_CHAR(tty), tty->process_char_map);
|
| 1049 |
|
|
set_bit(STOP_CHAR(tty), tty->process_char_map);
|
| 1050 |
|
|
}
|
| 1051 |
|
|
if (L_ISIG(tty)) {
|
| 1052 |
|
|
set_bit(INTR_CHAR(tty), tty->process_char_map);
|
| 1053 |
|
|
set_bit(QUIT_CHAR(tty), tty->process_char_map);
|
| 1054 |
|
|
set_bit(SUSP_CHAR(tty), tty->process_char_map);
|
| 1055 |
|
|
}
|
| 1056 |
|
|
clear_bit(__DISABLED_CHAR, tty->process_char_map);
|
| 1057 |
|
|
tty->raw = 0;
|
| 1058 |
|
|
tty->real_raw = 0;
|
| 1059 |
|
|
} else {
|
| 1060 |
|
|
tty->raw = 1;
|
| 1061 |
|
|
if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) &&
|
| 1062 |
|
|
(I_IGNPAR(tty) || !I_INPCK(tty)) &&
|
| 1063 |
|
|
(tty->driver->flags & TTY_DRIVER_REAL_RAW))
|
| 1064 |
|
|
tty->real_raw = 1;
|
| 1065 |
|
|
else
|
| 1066 |
|
|
tty->real_raw = 0;
|
| 1067 |
|
|
}
|
| 1068 |
|
|
n_tty_set_room(tty);
|
| 1069 |
|
|
}
|
| 1070 |
|
|
|
| 1071 |
|
|
/**
|
| 1072 |
|
|
* n_tty_close - close the ldisc for this tty
|
| 1073 |
|
|
* @tty: device
|
| 1074 |
|
|
*
|
| 1075 |
|
|
* Called from the terminal layer when this line discipline is
|
| 1076 |
|
|
* being shut down, either because of a close or becsuse of a
|
| 1077 |
|
|
* discipline change. The function will not be called while other
|
| 1078 |
|
|
* ldisc methods are in progress.
|
| 1079 |
|
|
*/
|
| 1080 |
|
|
|
| 1081 |
|
|
static void n_tty_close(struct tty_struct *tty)
|
| 1082 |
|
|
{
|
| 1083 |
|
|
n_tty_flush_buffer(tty);
|
| 1084 |
|
|
if (tty->read_buf) {
|
| 1085 |
|
|
free_buf(tty->read_buf);
|
| 1086 |
|
|
tty->read_buf = NULL;
|
| 1087 |
|
|
}
|
| 1088 |
|
|
}
|
| 1089 |
|
|
|
| 1090 |
|
|
/**
|
| 1091 |
|
|
* n_tty_open - open an ldisc
|
| 1092 |
|
|
* @tty: terminal to open
|
| 1093 |
|
|
*
|
| 1094 |
|
|
* Called when this line discipline is being attached to the
|
| 1095 |
|
|
* terminal device. Can sleep. Called serialized so that no
|
| 1096 |
|
|
* other events will occur in parallel. No further open will occur
|
| 1097 |
|
|
* until a close.
|
| 1098 |
|
|
*/
|
| 1099 |
|
|
|
| 1100 |
|
|
static int n_tty_open(struct tty_struct *tty)
|
| 1101 |
|
|
{
|
| 1102 |
|
|
if (!tty)
|
| 1103 |
|
|
return -EINVAL;
|
| 1104 |
|
|
|
| 1105 |
|
|
/* This one is ugly. Currently a malloc failure here can panic */
|
| 1106 |
|
|
if (!tty->read_buf) {
|
| 1107 |
|
|
tty->read_buf = alloc_buf();
|
| 1108 |
|
|
if (!tty->read_buf)
|
| 1109 |
|
|
return -ENOMEM;
|
| 1110 |
|
|
}
|
| 1111 |
|
|
memset(tty->read_buf, 0, N_TTY_BUF_SIZE);
|
| 1112 |
|
|
reset_buffer_flags(tty);
|
| 1113 |
|
|
tty->column = 0;
|
| 1114 |
|
|
n_tty_set_termios(tty, NULL);
|
| 1115 |
|
|
tty->minimum_to_wake = 1;
|
| 1116 |
|
|
tty->closing = 0;
|
| 1117 |
|
|
return 0;
|
| 1118 |
|
|
}
|
| 1119 |
|
|
|
| 1120 |
|
|
static inline int input_available_p(struct tty_struct *tty, int amt)
|
| 1121 |
|
|
{
|
| 1122 |
|
|
if (tty->icanon) {
|
| 1123 |
|
|
if (tty->canon_data)
|
| 1124 |
|
|
return 1;
|
| 1125 |
|
|
} else if (tty->read_cnt >= (amt ? amt : 1))
|
| 1126 |
|
|
return 1;
|
| 1127 |
|
|
|
| 1128 |
|
|
return 0;
|
| 1129 |
|
|
}
|
| 1130 |
|
|
|
| 1131 |
|
|
/**
|
| 1132 |
|
|
* copy_from_read_buf - copy read data directly
|
| 1133 |
|
|
* @tty: terminal device
|
| 1134 |
|
|
* @b: user data
|
| 1135 |
|
|
* @nr: size of data
|
| 1136 |
|
|
*
|
| 1137 |
|
|
* Helper function to speed up read_chan. It is only called when
|
| 1138 |
|
|
* ICANON is off; it copies characters straight from the tty queue to
|
| 1139 |
|
|
* user space directly. It can be profitably called twice; once to
|
| 1140 |
|
|
* drain the space from the tail pointer to the (physical) end of the
|
| 1141 |
|
|
* buffer, and once to drain the space from the (physical) beginning of
|
| 1142 |
|
|
* the buffer to head pointer.
|
| 1143 |
|
|
*
|
| 1144 |
|
|
* Called under the tty->atomic_read_lock sem
|
| 1145 |
|
|
*
|
| 1146 |
|
|
*/
|
| 1147 |
|
|
|
| 1148 |
|
|
static int copy_from_read_buf(struct tty_struct *tty,
|
| 1149 |
|
|
unsigned char __user **b,
|
| 1150 |
|
|
size_t *nr)
|
| 1151 |
|
|
|
| 1152 |
|
|
{
|
| 1153 |
|
|
int retval;
|
| 1154 |
|
|
size_t n;
|
| 1155 |
|
|
unsigned long flags;
|
| 1156 |
|
|
|
| 1157 |
|
|
retval = 0;
|
| 1158 |
|
|
spin_lock_irqsave(&tty->read_lock, flags);
|
| 1159 |
|
|
n = min(tty->read_cnt, N_TTY_BUF_SIZE - tty->read_tail);
|
| 1160 |
|
|
n = min(*nr, n);
|
| 1161 |
|
|
spin_unlock_irqrestore(&tty->read_lock, flags);
|
| 1162 |
|
|
if (n) {
|
| 1163 |
|
|
retval = copy_to_user(*b, &tty->read_buf[tty->read_tail], n);
|
| 1164 |
|
|
n -= retval;
|
| 1165 |
|
|
tty_audit_add_data(tty, &tty->read_buf[tty->read_tail], n);
|
| 1166 |
|
|
spin_lock_irqsave(&tty->read_lock, flags);
|
| 1167 |
|
|
tty->read_tail = (tty->read_tail + n) & (N_TTY_BUF_SIZE-1);
|
| 1168 |
|
|
tty->read_cnt -= n;
|
| 1169 |
|
|
spin_unlock_irqrestore(&tty->read_lock, flags);
|
| 1170 |
|
|
*b += n;
|
| 1171 |
|
|
*nr -= n;
|
| 1172 |
|
|
}
|
| 1173 |
|
|
return retval;
|
| 1174 |
|
|
}
|
| 1175 |
|
|
|
| 1176 |
|
|
extern ssize_t redirected_tty_write(struct file *,const char *,size_t,loff_t *);
|
| 1177 |
|
|
|
| 1178 |
|
|
/**
|
| 1179 |
|
|
* job_control - check job control
|
| 1180 |
|
|
* @tty: tty
|
| 1181 |
|
|
* @file: file handle
|
| 1182 |
|
|
*
|
| 1183 |
|
|
* Perform job control management checks on this file/tty descriptor
|
| 1184 |
|
|
* and if appropriate send any needed signals and return a negative
|
| 1185 |
|
|
* error code if action should be taken.
|
| 1186 |
|
|
*/
|
| 1187 |
|
|
|
| 1188 |
|
|
static int job_control(struct tty_struct *tty, struct file *file)
|
| 1189 |
|
|
{
|
| 1190 |
|
|
/* Job control check -- must be done at start and after
|
| 1191 |
|
|
every sleep (POSIX.1 7.1.1.4). */
|
| 1192 |
|
|
/* NOTE: not yet done after every sleep pending a thorough
|
| 1193 |
|
|
check of the logic of this change. -- jlc */
|
| 1194 |
|
|
/* don't stop on /dev/console */
|
| 1195 |
|
|
if (file->f_op->write != redirected_tty_write &&
|
| 1196 |
|
|
current->signal->tty == tty) {
|
| 1197 |
|
|
if (!tty->pgrp)
|
| 1198 |
|
|
printk("read_chan: no tty->pgrp!\n");
|
| 1199 |
|
|
else if (task_pgrp(current) != tty->pgrp) {
|
| 1200 |
|
|
if (is_ignored(SIGTTIN) ||
|
| 1201 |
|
|
is_current_pgrp_orphaned())
|
| 1202 |
|
|
return -EIO;
|
| 1203 |
|
|
kill_pgrp(task_pgrp(current), SIGTTIN, 1);
|
| 1204 |
|
|
set_thread_flag(TIF_SIGPENDING);
|
| 1205 |
|
|
return -ERESTARTSYS;
|
| 1206 |
|
|
}
|
| 1207 |
|
|
}
|
| 1208 |
|
|
return 0;
|
| 1209 |
|
|
}
|
| 1210 |
|
|
|
| 1211 |
|
|
|
| 1212 |
|
|
/**
|
| 1213 |
|
|
* read_chan - read function for tty
|
| 1214 |
|
|
* @tty: tty device
|
| 1215 |
|
|
* @file: file object
|
| 1216 |
|
|
* @buf: userspace buffer pointer
|
| 1217 |
|
|
* @nr: size of I/O
|
| 1218 |
|
|
*
|
| 1219 |
|
|
* Perform reads for the line discipline. We are guaranteed that the
|
| 1220 |
|
|
* line discipline will not be closed under us but we may get multiple
|
| 1221 |
|
|
* parallel readers and must handle this ourselves. We may also get
|
| 1222 |
|
|
* a hangup. Always called in user context, may sleep.
|
| 1223 |
|
|
*
|
| 1224 |
|
|
* This code must be sure never to sleep through a hangup.
|
| 1225 |
|
|
*/
|
| 1226 |
|
|
|
| 1227 |
|
|
static ssize_t read_chan(struct tty_struct *tty, struct file *file,
|
| 1228 |
|
|
unsigned char __user *buf, size_t nr)
|
| 1229 |
|
|
{
|
| 1230 |
|
|
unsigned char __user *b = buf;
|
| 1231 |
|
|
DECLARE_WAITQUEUE(wait, current);
|
| 1232 |
|
|
int c;
|
| 1233 |
|
|
int minimum, time;
|
| 1234 |
|
|
ssize_t retval = 0;
|
| 1235 |
|
|
ssize_t size;
|
| 1236 |
|
|
long timeout;
|
| 1237 |
|
|
unsigned long flags;
|
| 1238 |
|
|
|
| 1239 |
|
|
do_it_again:
|
| 1240 |
|
|
|
| 1241 |
|
|
if (!tty->read_buf) {
|
| 1242 |
|
|
printk("n_tty_read_chan: called with read_buf == NULL?!?\n");
|
| 1243 |
|
|
return -EIO;
|
| 1244 |
|
|
}
|
| 1245 |
|
|
|
| 1246 |
|
|
c = job_control(tty, file);
|
| 1247 |
|
|
if(c < 0)
|
| 1248 |
|
|
return c;
|
| 1249 |
|
|
|
| 1250 |
|
|
minimum = time = 0;
|
| 1251 |
|
|
timeout = MAX_SCHEDULE_TIMEOUT;
|
| 1252 |
|
|
if (!tty->icanon) {
|
| 1253 |
|
|
time = (HZ / 10) * TIME_CHAR(tty);
|
| 1254 |
|
|
minimum = MIN_CHAR(tty);
|
| 1255 |
|
|
if (minimum) {
|
| 1256 |
|
|
if (time)
|
| 1257 |
|
|
tty->minimum_to_wake = 1;
|
| 1258 |
|
|
else if (!waitqueue_active(&tty->read_wait) ||
|
| 1259 |
|
|
(tty->minimum_to_wake > minimum))
|
| 1260 |
|
|
tty->minimum_to_wake = minimum;
|
| 1261 |
|
|
} else {
|
| 1262 |
|
|
timeout = 0;
|
| 1263 |
|
|
if (time) {
|
| 1264 |
|
|
timeout = time;
|
| 1265 |
|
|
time = 0;
|
| 1266 |
|
|
}
|
| 1267 |
|
|
tty->minimum_to_wake = minimum = 1;
|
| 1268 |
|
|
}
|
| 1269 |
|
|
}
|
| 1270 |
|
|
|
| 1271 |
|
|
/*
|
| 1272 |
|
|
* Internal serialization of reads.
|
| 1273 |
|
|
*/
|
| 1274 |
|
|
if (file->f_flags & O_NONBLOCK) {
|
| 1275 |
|
|
if (!mutex_trylock(&tty->atomic_read_lock))
|
| 1276 |
|
|
return -EAGAIN;
|
| 1277 |
|
|
}
|
| 1278 |
|
|
else {
|
| 1279 |
|
|
if (mutex_lock_interruptible(&tty->atomic_read_lock))
|
| 1280 |
|
|
return -ERESTARTSYS;
|
| 1281 |
|
|
}
|
| 1282 |
|
|
|
| 1283 |
|
|
add_wait_queue(&tty->read_wait, &wait);
|
| 1284 |
|
|
while (nr) {
|
| 1285 |
|
|
/* First test for status change. */
|
| 1286 |
|
|
if (tty->packet && tty->link->ctrl_status) {
|
| 1287 |
|
|
unsigned char cs;
|
| 1288 |
|
|
if (b != buf)
|
| 1289 |
|
|
break;
|
| 1290 |
|
|
cs = tty->link->ctrl_status;
|
| 1291 |
|
|
tty->link->ctrl_status = 0;
|
| 1292 |
|
|
if (tty_put_user(tty, cs, b++)) {
|
| 1293 |
|
|
retval = -EFAULT;
|
| 1294 |
|
|
b--;
|
| 1295 |
|
|
break;
|
| 1296 |
|
|
}
|
| 1297 |
|
|
nr--;
|
| 1298 |
|
|
break;
|
| 1299 |
|
|
}
|
| 1300 |
|
|
/* This statement must be first before checking for input
|
| 1301 |
|
|
so that any interrupt will set the state back to
|
| 1302 |
|
|
TASK_RUNNING. */
|
| 1303 |
|
|
set_current_state(TASK_INTERRUPTIBLE);
|
| 1304 |
|
|
|
| 1305 |
|
|
if (((minimum - (b - buf)) < tty->minimum_to_wake) &&
|
| 1306 |
|
|
((minimum - (b - buf)) >= 1))
|
| 1307 |
|
|
tty->minimum_to_wake = (minimum - (b - buf));
|
| 1308 |
|
|
|
| 1309 |
|
|
if (!input_available_p(tty, 0)) {
|
| 1310 |
|
|
if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) {
|
| 1311 |
|
|
retval = -EIO;
|
| 1312 |
|
|
break;
|
| 1313 |
|
|
}
|
| 1314 |
|
|
if (tty_hung_up_p(file))
|
| 1315 |
|
|
break;
|
| 1316 |
|
|
if (!timeout)
|
| 1317 |
|
|
break;
|
| 1318 |
|
|
if (file->f_flags & O_NONBLOCK) {
|
| 1319 |
|
|
retval = -EAGAIN;
|
| 1320 |
|
|
break;
|
| 1321 |
|
|
}
|
| 1322 |
|
|
if (signal_pending(current)) {
|
| 1323 |
|
|
retval = -ERESTARTSYS;
|
| 1324 |
|
|
break;
|
| 1325 |
|
|
}
|
| 1326 |
|
|
n_tty_set_room(tty);
|
| 1327 |
|
|
timeout = schedule_timeout(timeout);
|
| 1328 |
|
|
continue;
|
| 1329 |
|
|
}
|
| 1330 |
|
|
__set_current_state(TASK_RUNNING);
|
| 1331 |
|
|
|
| 1332 |
|
|
/* Deal with packet mode. */
|
| 1333 |
|
|
if (tty->packet && b == buf) {
|
| 1334 |
|
|
if (tty_put_user(tty, TIOCPKT_DATA, b++)) {
|
| 1335 |
|
|
retval = -EFAULT;
|
| 1336 |
|
|
b--;
|
| 1337 |
|
|
break;
|
| 1338 |
|
|
}
|
| 1339 |
|
|
nr--;
|
| 1340 |
|
|
}
|
| 1341 |
|
|
|
| 1342 |
|
|
if (tty->icanon) {
|
| 1343 |
|
|
/* N.B. avoid overrun if nr == 0 */
|
| 1344 |
|
|
while (nr && tty->read_cnt) {
|
| 1345 |
|
|
int eol;
|
| 1346 |
|
|
|
| 1347 |
|
|
eol = test_and_clear_bit(tty->read_tail,
|
| 1348 |
|
|
tty->read_flags);
|
| 1349 |
|
|
c = tty->read_buf[tty->read_tail];
|
| 1350 |
|
|
spin_lock_irqsave(&tty->read_lock, flags);
|
| 1351 |
|
|
tty->read_tail = ((tty->read_tail+1) &
|
| 1352 |
|
|
(N_TTY_BUF_SIZE-1));
|
| 1353 |
|
|
tty->read_cnt--;
|
| 1354 |
|
|
if (eol) {
|
| 1355 |
|
|
/* this test should be redundant:
|
| 1356 |
|
|
* we shouldn't be reading data if
|
| 1357 |
|
|
* canon_data is 0
|
| 1358 |
|
|
*/
|
| 1359 |
|
|
if (--tty->canon_data < 0)
|
| 1360 |
|
|
tty->canon_data = 0;
|
| 1361 |
|
|
}
|
| 1362 |
|
|
spin_unlock_irqrestore(&tty->read_lock, flags);
|
| 1363 |
|
|
|
| 1364 |
|
|
if (!eol || (c != __DISABLED_CHAR)) {
|
| 1365 |
|
|
if (tty_put_user(tty, c, b++)) {
|
| 1366 |
|
|
retval = -EFAULT;
|
| 1367 |
|
|
b--;
|
| 1368 |
|
|
break;
|
| 1369 |
|
|
}
|
| 1370 |
|
|
nr--;
|
| 1371 |
|
|
}
|
| 1372 |
|
|
if (eol) {
|
| 1373 |
|
|
tty_audit_push(tty);
|
| 1374 |
|
|
break;
|
| 1375 |
|
|
}
|
| 1376 |
|
|
}
|
| 1377 |
|
|
if (retval)
|
| 1378 |
|
|
break;
|
| 1379 |
|
|
} else {
|
| 1380 |
|
|
int uncopied;
|
| 1381 |
|
|
uncopied = copy_from_read_buf(tty, &b, &nr);
|
| 1382 |
|
|
uncopied += copy_from_read_buf(tty, &b, &nr);
|
| 1383 |
|
|
if (uncopied) {
|
| 1384 |
|
|
retval = -EFAULT;
|
| 1385 |
|
|
break;
|
| 1386 |
|
|
}
|
| 1387 |
|
|
}
|
| 1388 |
|
|
|
| 1389 |
|
|
/* If there is enough space in the read buffer now, let the
|
| 1390 |
|
|
* low-level driver know. We use n_tty_chars_in_buffer() to
|
| 1391 |
|
|
* check the buffer, as it now knows about canonical mode.
|
| 1392 |
|
|
* Otherwise, if the driver is throttled and the line is
|
| 1393 |
|
|
* longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode,
|
| 1394 |
|
|
* we won't get any more characters.
|
| 1395 |
|
|
*/
|
| 1396 |
|
|
if (n_tty_chars_in_buffer(tty) <= TTY_THRESHOLD_UNTHROTTLE) {
|
| 1397 |
|
|
n_tty_set_room(tty);
|
| 1398 |
|
|
check_unthrottle(tty);
|
| 1399 |
|
|
}
|
| 1400 |
|
|
|
| 1401 |
|
|
if (b - buf >= minimum)
|
| 1402 |
|
|
break;
|
| 1403 |
|
|
if (time)
|
| 1404 |
|
|
timeout = time;
|
| 1405 |
|
|
}
|
| 1406 |
|
|
mutex_unlock(&tty->atomic_read_lock);
|
| 1407 |
|
|
remove_wait_queue(&tty->read_wait, &wait);
|
| 1408 |
|
|
|
| 1409 |
|
|
if (!waitqueue_active(&tty->read_wait))
|
| 1410 |
|
|
tty->minimum_to_wake = minimum;
|
| 1411 |
|
|
|
| 1412 |
|
|
__set_current_state(TASK_RUNNING);
|
| 1413 |
|
|
size = b - buf;
|
| 1414 |
|
|
if (size) {
|
| 1415 |
|
|
retval = size;
|
| 1416 |
|
|
if (nr)
|
| 1417 |
|
|
clear_bit(TTY_PUSH, &tty->flags);
|
| 1418 |
|
|
} else if (test_and_clear_bit(TTY_PUSH, &tty->flags))
|
| 1419 |
|
|
goto do_it_again;
|
| 1420 |
|
|
|
| 1421 |
|
|
n_tty_set_room(tty);
|
| 1422 |
|
|
|
| 1423 |
|
|
return retval;
|
| 1424 |
|
|
}
|
| 1425 |
|
|
|
| 1426 |
|
|
/**
|
| 1427 |
|
|
* write_chan - write function for tty
|
| 1428 |
|
|
* @tty: tty device
|
| 1429 |
|
|
* @file: file object
|
| 1430 |
|
|
* @buf: userspace buffer pointer
|
| 1431 |
|
|
* @nr: size of I/O
|
| 1432 |
|
|
*
|
| 1433 |
|
|
* Write function of the terminal device. This is serialized with
|
| 1434 |
|
|
* respect to other write callers but not to termios changes, reads
|
| 1435 |
|
|
* and other such events. We must be careful with N_TTY as the receive
|
| 1436 |
|
|
* code will echo characters, thus calling driver write methods.
|
| 1437 |
|
|
*
|
| 1438 |
|
|
* This code must be sure never to sleep through a hangup.
|
| 1439 |
|
|
*/
|
| 1440 |
|
|
|
| 1441 |
|
|
static ssize_t write_chan(struct tty_struct * tty, struct file * file,
|
| 1442 |
|
|
const unsigned char * buf, size_t nr)
|
| 1443 |
|
|
{
|
| 1444 |
|
|
const unsigned char *b = buf;
|
| 1445 |
|
|
DECLARE_WAITQUEUE(wait, current);
|
| 1446 |
|
|
int c;
|
| 1447 |
|
|
ssize_t retval = 0;
|
| 1448 |
|
|
|
| 1449 |
|
|
/* Job control check -- must be done at start (POSIX.1 7.1.1.4). */
|
| 1450 |
|
|
if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) {
|
| 1451 |
|
|
retval = tty_check_change(tty);
|
| 1452 |
|
|
if (retval)
|
| 1453 |
|
|
return retval;
|
| 1454 |
|
|
}
|
| 1455 |
|
|
|
| 1456 |
|
|
add_wait_queue(&tty->write_wait, &wait);
|
| 1457 |
|
|
while (1) {
|
| 1458 |
|
|
set_current_state(TASK_INTERRUPTIBLE);
|
| 1459 |
|
|
if (signal_pending(current)) {
|
| 1460 |
|
|
retval = -ERESTARTSYS;
|
| 1461 |
|
|
break;
|
| 1462 |
|
|
}
|
| 1463 |
|
|
if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) {
|
| 1464 |
|
|
retval = -EIO;
|
| 1465 |
|
|
break;
|
| 1466 |
|
|
}
|
| 1467 |
|
|
if (O_OPOST(tty) && !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) {
|
| 1468 |
|
|
while (nr > 0) {
|
| 1469 |
|
|
ssize_t num = opost_block(tty, b, nr);
|
| 1470 |
|
|
if (num < 0) {
|
| 1471 |
|
|
if (num == -EAGAIN)
|
| 1472 |
|
|
break;
|
| 1473 |
|
|
retval = num;
|
| 1474 |
|
|
goto break_out;
|
| 1475 |
|
|
}
|
| 1476 |
|
|
b += num;
|
| 1477 |
|
|
nr -= num;
|
| 1478 |
|
|
if (nr == 0)
|
| 1479 |
|
|
break;
|
| 1480 |
|
|
c = *b;
|
| 1481 |
|
|
if (opost(c, tty) < 0)
|
| 1482 |
|
|
break;
|
| 1483 |
|
|
b++; nr--;
|
| 1484 |
|
|
}
|
| 1485 |
|
|
if (tty->driver->flush_chars)
|
| 1486 |
|
|
tty->driver->flush_chars(tty);
|
| 1487 |
|
|
} else {
|
| 1488 |
|
|
while (nr > 0) {
|
| 1489 |
|
|
c = tty->driver->write(tty, b, nr);
|
| 1490 |
|
|
if (c < 0) {
|
| 1491 |
|
|
retval = c;
|
| 1492 |
|
|
goto break_out;
|
| 1493 |
|
|
}
|
| 1494 |
|
|
if (!c)
|
| 1495 |
|
|
break;
|
| 1496 |
|
|
b += c;
|
| 1497 |
|
|
nr -= c;
|
| 1498 |
|
|
}
|
| 1499 |
|
|
}
|
| 1500 |
|
|
if (!nr)
|
| 1501 |
|
|
break;
|
| 1502 |
|
|
if (file->f_flags & O_NONBLOCK) {
|
| 1503 |
|
|
retval = -EAGAIN;
|
| 1504 |
|
|
break;
|
| 1505 |
|
|
}
|
| 1506 |
|
|
schedule();
|
| 1507 |
|
|
}
|
| 1508 |
|
|
break_out:
|
| 1509 |
|
|
__set_current_state(TASK_RUNNING);
|
| 1510 |
|
|
remove_wait_queue(&tty->write_wait, &wait);
|
| 1511 |
|
|
return (b - buf) ? b - buf : retval;
|
| 1512 |
|
|
}
|
| 1513 |
|
|
|
| 1514 |
|
|
/**
|
| 1515 |
|
|
* normal_poll - poll method for N_TTY
|
| 1516 |
|
|
* @tty: terminal device
|
| 1517 |
|
|
* @file: file accessing it
|
| 1518 |
|
|
* @wait: poll table
|
| 1519 |
|
|
*
|
| 1520 |
|
|
* Called when the line discipline is asked to poll() for data or
|
| 1521 |
|
|
* for special events. This code is not serialized with respect to
|
| 1522 |
|
|
* other events save open/close.
|
| 1523 |
|
|
*
|
| 1524 |
|
|
* This code must be sure never to sleep through a hangup.
|
| 1525 |
|
|
* Called without the kernel lock held - fine
|
| 1526 |
|
|
*
|
| 1527 |
|
|
* FIXME: if someone changes the VMIN or discipline settings for the
|
| 1528 |
|
|
* terminal while another process is in poll() the poll does not
|
| 1529 |
|
|
* recompute the new limits. Possibly set_termios should issue
|
| 1530 |
|
|
* a read wakeup to fix this bug.
|
| 1531 |
|
|
*/
|
| 1532 |
|
|
|
| 1533 |
|
|
static unsigned int normal_poll(struct tty_struct * tty, struct file * file, poll_table *wait)
|
| 1534 |
|
|
{
|
| 1535 |
|
|
unsigned int mask = 0;
|
| 1536 |
|
|
|
| 1537 |
|
|
poll_wait(file, &tty->read_wait, wait);
|
| 1538 |
|
|
poll_wait(file, &tty->write_wait, wait);
|
| 1539 |
|
|
if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty)))
|
| 1540 |
|
|
mask |= POLLIN | POLLRDNORM;
|
| 1541 |
|
|
if (tty->packet && tty->link->ctrl_status)
|
| 1542 |
|
|
mask |= POLLPRI | POLLIN | POLLRDNORM;
|
| 1543 |
|
|
if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
|
| 1544 |
|
|
mask |= POLLHUP;
|
| 1545 |
|
|
if (tty_hung_up_p(file))
|
| 1546 |
|
|
mask |= POLLHUP;
|
| 1547 |
|
|
if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) {
|
| 1548 |
|
|
if (MIN_CHAR(tty) && !TIME_CHAR(tty))
|
| 1549 |
|
|
tty->minimum_to_wake = MIN_CHAR(tty);
|
| 1550 |
|
|
else
|
| 1551 |
|
|
tty->minimum_to_wake = 1;
|
| 1552 |
|
|
}
|
| 1553 |
|
|
if (!tty_is_writelocked(tty) &&
|
| 1554 |
|
|
tty->driver->chars_in_buffer(tty) < WAKEUP_CHARS &&
|
| 1555 |
|
|
tty->driver->write_room(tty) > 0)
|
| 1556 |
|
|
mask |= POLLOUT | POLLWRNORM;
|
| 1557 |
|
|
return mask;
|
| 1558 |
|
|
}
|
| 1559 |
|
|
|
| 1560 |
|
|
struct tty_ldisc tty_ldisc_N_TTY = {
|
| 1561 |
|
|
.magic = TTY_LDISC_MAGIC,
|
| 1562 |
|
|
.name = "n_tty",
|
| 1563 |
|
|
.open = n_tty_open,
|
| 1564 |
|
|
.close = n_tty_close,
|
| 1565 |
|
|
.flush_buffer = n_tty_flush_buffer,
|
| 1566 |
|
|
.chars_in_buffer = n_tty_chars_in_buffer,
|
| 1567 |
|
|
.read = read_chan,
|
| 1568 |
|
|
.write = write_chan,
|
| 1569 |
|
|
.ioctl = n_tty_ioctl,
|
| 1570 |
|
|
.set_termios = n_tty_set_termios,
|
| 1571 |
|
|
.poll = normal_poll,
|
| 1572 |
|
|
.receive_buf = n_tty_receive_buf,
|
| 1573 |
|
|
.write_wakeup = n_tty_write_wakeup
|
| 1574 |
|
|
};
|
| 1575 |
|
|
|
