2005-04-16 16:20:36 -06:00
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/*
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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 <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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2005-09-10 01:26:38 -06:00
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unsigned int prio = in_interrupt() ? GFP_ATOMIC : GFP_KERNEL;
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2005-04-16 16:20:36 -06:00
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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 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 inline 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 semaphore 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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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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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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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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/**
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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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* opost - 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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* Perform OPOST processing. Returns -1 when the output device is
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* full and the character must be retried. Note that Linux currently
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* ignores TABDLY, CRDLY, VTDLY, FFDLY and NLDLY. They simply aren't
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* relevant in the world today. If you ever need them, add them here.
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*
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* Called from both the receive and transmit sides and can be called
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* re-entrantly. Relies on lock_kernel() still.
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*/
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static int opost(unsigned char c, struct tty_struct *tty)
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{
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int space, spaces;
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space = tty->driver->write_room(tty);
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if (!space)
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return -1;
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if (O_OPOST(tty)) {
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switch (c) {
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case '\n':
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if (O_ONLRET(tty))
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tty->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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tty->driver->put_char(tty, '\r');
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tty->column = 0;
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}
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tty->canon_column = tty->column;
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break;
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case '\r':
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if (O_ONOCR(tty) && tty->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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tty->canon_column = tty->column = 0;
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break;
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}
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tty->canon_column = tty->column = 0;
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break;
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case '\t':
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spaces = 8 - (tty->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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tty->column += spaces;
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tty->driver->write(tty, " ", spaces);
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return 0;
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}
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tty->column += spaces;
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break;
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case '\b':
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if (tty->column > 0)
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tty->column--;
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break;
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default:
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if (O_OLCUC(tty))
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c = toupper(c);
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if (!iscntrl(c) && !is_continuation(c, tty))
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tty->column++;
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break;
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}
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}
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tty->driver->put_char(tty, c);
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return 0;
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}
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/**
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* opost_block - block postprocess
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* @tty: terminal device
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* @inbuf: user buffer
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* @nr: number of bytes
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*
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* This path is used to speed up block console writes, among other
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* things when processing blocks of output data. It handles only
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* the simple cases normally found and helps to generate blocks of
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* symbols for the console driver and thus improve performance.
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*
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* Called from write_chan under the tty layer write lock.
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*/
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static ssize_t opost_block(struct tty_struct * tty,
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const unsigned char * buf, unsigned int nr)
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{
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int space;
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int i;
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const unsigned char *cp;
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space = tty->driver->write_room(tty);
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if (!space)
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return 0;
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if (nr > space)
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nr = space;
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for (i = 0, cp = buf; i < nr; i++, cp++) {
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switch (*cp) {
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case '\n':
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if (O_ONLRET(tty))
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tty->column = 0;
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if (O_ONLCR(tty))
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goto break_out;
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tty->canon_column = tty->column;
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break;
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case '\r':
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if (O_ONOCR(tty) && tty->column == 0)
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goto break_out;
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if (O_OCRNL(tty))
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goto break_out;
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tty->canon_column = tty->column = 0;
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break;
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case '\t':
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goto break_out;
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case '\b':
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if (tty->column > 0)
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tty->column--;
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break;
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default:
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if (O_OLCUC(tty))
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goto break_out;
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if (!iscntrl(*cp))
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tty->column++;
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break;
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}
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}
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break_out:
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if (tty->driver->flush_chars)
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tty->driver->flush_chars(tty);
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i = tty->driver->write(tty, buf, i);
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return i;
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}
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/**
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* put_char - write character to driver
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* @c: character (or part of unicode symbol)
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* @tty: terminal device
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*
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* Queue a byte to the driver layer for output
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*/
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static inline void put_char(unsigned char c, struct tty_struct *tty)
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{
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tty->driver->put_char(tty, c);
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}
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/**
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* echo_char - echo characters
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* @c: unicode byte to echo
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* @tty: terminal device
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*
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* Echo user input back onto the screen. This must be called only when
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* L_ECHO(tty) is true. Called from the driver receive_buf path.
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*/
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static void echo_char(unsigned char c, struct tty_struct *tty)
|
|
|
|
{
|
|
|
|
if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') {
|
|
|
|
put_char('^', tty);
|
|
|
|
put_char(c ^ 0100, tty);
|
|
|
|
tty->column += 2;
|
|
|
|
} else
|
|
|
|
opost(c, tty);
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline void finish_erasing(struct tty_struct *tty)
|
|
|
|
{
|
|
|
|
if (tty->erasing) {
|
|
|
|
put_char('/', tty);
|
|
|
|
tty->column++;
|
|
|
|
tty->erasing = 0;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* eraser - handle erase function
|
|
|
|
* @c: character input
|
|
|
|
* @tty: terminal device
|
|
|
|
*
|
|
|
|
* Perform erase and neccessary output when an erase character is
|
|
|
|
* present in the stream from the driver layer. Handles the complexities
|
|
|
|
* of UTF-8 multibyte symbols.
|
|
|
|
*/
|
|
|
|
|
|
|
|
static void eraser(unsigned char c, struct tty_struct *tty)
|
|
|
|
{
|
|
|
|
enum { ERASE, WERASE, KILL } kill_type;
|
|
|
|
int head, seen_alnums, cnt;
|
|
|
|
unsigned long flags;
|
|
|
|
|
|
|
|
if (tty->read_head == tty->canon_head) {
|
|
|
|
/* opost('\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(&tty->read_lock, flags);
|
|
|
|
tty->read_cnt -= ((tty->read_head - tty->canon_head) &
|
|
|
|
(N_TTY_BUF_SIZE - 1));
|
|
|
|
tty->read_head = tty->canon_head;
|
|
|
|
spin_unlock_irqrestore(&tty->read_lock, flags);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) {
|
|
|
|
spin_lock_irqsave(&tty->read_lock, flags);
|
|
|
|
tty->read_cnt -= ((tty->read_head - tty->canon_head) &
|
|
|
|
(N_TTY_BUF_SIZE - 1));
|
|
|
|
tty->read_head = tty->canon_head;
|
|
|
|
spin_unlock_irqrestore(&tty->read_lock, flags);
|
|
|
|
finish_erasing(tty);
|
|
|
|
echo_char(KILL_CHAR(tty), tty);
|
|
|
|
/* Add a newline if ECHOK is on and ECHOKE is off. */
|
|
|
|
if (L_ECHOK(tty))
|
|
|
|
opost('\n', tty);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
kill_type = KILL;
|
|
|
|
}
|
|
|
|
|
|
|
|
seen_alnums = 0;
|
|
|
|
while (tty->read_head != tty->canon_head) {
|
|
|
|
head = tty->read_head;
|
|
|
|
|
|
|
|
/* erase a single possibly multibyte character */
|
|
|
|
do {
|
|
|
|
head = (head - 1) & (N_TTY_BUF_SIZE-1);
|
|
|
|
c = tty->read_buf[head];
|
|
|
|
} while (is_continuation(c, tty) && head != tty->canon_head);
|
|
|
|
|
|
|
|
/* 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 = (tty->read_head - head) & (N_TTY_BUF_SIZE-1);
|
|
|
|
spin_lock_irqsave(&tty->read_lock, flags);
|
|
|
|
tty->read_head = head;
|
|
|
|
tty->read_cnt -= cnt;
|
|
|
|
spin_unlock_irqrestore(&tty->read_lock, flags);
|
|
|
|
if (L_ECHO(tty)) {
|
|
|
|
if (L_ECHOPRT(tty)) {
|
|
|
|
if (!tty->erasing) {
|
|
|
|
put_char('\\', tty);
|
|
|
|
tty->column++;
|
|
|
|
tty->erasing = 1;
|
|
|
|
}
|
|
|
|
/* if cnt > 1, output a multi-byte character */
|
|
|
|
echo_char(c, tty);
|
|
|
|
while (--cnt > 0) {
|
|
|
|
head = (head+1) & (N_TTY_BUF_SIZE-1);
|
|
|
|
put_char(tty->read_buf[head], tty);
|
|
|
|
}
|
|
|
|
} else if (kill_type == ERASE && !L_ECHOE(tty)) {
|
|
|
|
echo_char(ERASE_CHAR(tty), tty);
|
|
|
|
} else if (c == '\t') {
|
|
|
|
unsigned int col = tty->canon_column;
|
|
|
|
unsigned long tail = tty->canon_head;
|
|
|
|
|
|
|
|
/* Find the column of the last char. */
|
|
|
|
while (tail != tty->read_head) {
|
|
|
|
c = tty->read_buf[tail];
|
|
|
|
if (c == '\t')
|
|
|
|
col = (col | 7) + 1;
|
|
|
|
else if (iscntrl(c)) {
|
|
|
|
if (L_ECHOCTL(tty))
|
|
|
|
col += 2;
|
|
|
|
} else if (!is_continuation(c, tty))
|
|
|
|
col++;
|
|
|
|
tail = (tail+1) & (N_TTY_BUF_SIZE-1);
|
|
|
|
}
|
|
|
|
|
|
|
|
/* should never happen */
|
|
|
|
if (tty->column > 0x80000000)
|
|
|
|
tty->column = 0;
|
|
|
|
|
|
|
|
/* Now backup to that column. */
|
|
|
|
while (tty->column > col) {
|
|
|
|
/* Can't use opost here. */
|
|
|
|
put_char('\b', tty);
|
|
|
|
if (tty->column > 0)
|
|
|
|
tty->column--;
|
|
|
|
}
|
|
|
|
} else {
|
|
|
|
if (iscntrl(c) && L_ECHOCTL(tty)) {
|
|
|
|
put_char('\b', tty);
|
|
|
|
put_char(' ', tty);
|
|
|
|
put_char('\b', tty);
|
|
|
|
if (tty->column > 0)
|
|
|
|
tty->column--;
|
|
|
|
}
|
|
|
|
if (!iscntrl(c) || L_ECHOCTL(tty)) {
|
|
|
|
put_char('\b', tty);
|
|
|
|
put_char(' ', tty);
|
|
|
|
put_char('\b', tty);
|
|
|
|
if (tty->column > 0)
|
|
|
|
tty->column--;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
if (kill_type == ERASE)
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
if (tty->read_head == tty->canon_head)
|
|
|
|
finish_erasing(tty);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* isig - handle the ISIG optio
|
|
|
|
* @sig: signal
|
|
|
|
* @tty: terminal
|
|
|
|
* @flush: force flush
|
|
|
|
*
|
|
|
|
* Called when a signal is being sent due to terminal input. This
|
|
|
|
* may caus terminal flushing to take place according to the termios
|
|
|
|
* settings and character used. Called from the driver receive_buf
|
|
|
|
* path so serialized.
|
|
|
|
*/
|
|
|
|
|
|
|
|
static inline void isig(int sig, struct tty_struct *tty, int flush)
|
|
|
|
{
|
|
|
|
if (tty->pgrp > 0)
|
|
|
|
kill_pg(tty->pgrp, sig, 1);
|
|
|
|
if (flush || !L_NOFLSH(tty)) {
|
|
|
|
n_tty_flush_buffer(tty);
|
|
|
|
if (tty->driver->flush_buffer)
|
|
|
|
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)
|
|
|
|
{
|
|
|
|
if (I_IGNBRK(tty))
|
|
|
|
return;
|
|
|
|
if (I_BRKINT(tty)) {
|
|
|
|
isig(SIGINT, tty, 1);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
if (I_PARMRK(tty)) {
|
|
|
|
put_tty_queue('\377', tty);
|
|
|
|
put_tty_queue('\0', tty);
|
|
|
|
}
|
|
|
|
put_tty_queue('\0', tty);
|
|
|
|
wake_up_interruptible(&tty->read_wait);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* n_tty_receive_overrun - handle overrun reporting
|
|
|
|
* @tty: terminal
|
|
|
|
*
|
|
|
|
* Data arrived faster than we could process it. While the tty
|
|
|
|
* driver has flagged this the bits that were missed are gone
|
|
|
|
* forever.
|
|
|
|
*
|
|
|
|
* Called from the receive_buf path so single threaded. Does not
|
|
|
|
* need locking as num_overrun and overrun_time are function
|
|
|
|
* private.
|
|
|
|
*/
|
|
|
|
|
|
|
|
static inline void n_tty_receive_overrun(struct tty_struct *tty)
|
|
|
|
{
|
|
|
|
char buf[64];
|
|
|
|
|
|
|
|
tty->num_overrun++;
|
|
|
|
if (time_before(tty->overrun_time, jiffies - HZ) ||
|
|
|
|
time_after(tty->overrun_time, jiffies)) {
|
|
|
|
printk(KERN_WARNING "%s: %d input overrun(s)\n",
|
|
|
|
tty_name(tty, buf),
|
|
|
|
tty->num_overrun);
|
|
|
|
tty->overrun_time = jiffies;
|
|
|
|
tty->num_overrun = 0;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* n_tty_receive_parity_error - error notifier
|
|
|
|
* @tty: terminal device
|
|
|
|
* @c: character
|
|
|
|
*
|
|
|
|
* Process a parity error and queue the right data to indicate
|
|
|
|
* the error case if neccessary. Locking as per n_tty_receive_buf.
|
|
|
|
*/
|
|
|
|
static inline void n_tty_receive_parity_error(struct tty_struct *tty,
|
|
|
|
unsigned char c)
|
|
|
|
{
|
|
|
|
if (I_IGNPAR(tty)) {
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
if (I_PARMRK(tty)) {
|
|
|
|
put_tty_queue('\377', tty);
|
|
|
|
put_tty_queue('\0', tty);
|
|
|
|
put_tty_queue(c, tty);
|
|
|
|
} else if (I_INPCK(tty))
|
|
|
|
put_tty_queue('\0', tty);
|
|
|
|
else
|
|
|
|
put_tty_queue(c, tty);
|
|
|
|
wake_up_interruptible(&tty->read_wait);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* n_tty_receive_char - perform processing
|
|
|
|
* @tty: terminal device
|
|
|
|
* @c: character
|
|
|
|
*
|
|
|
|
* Process an individual character of input received from the driver.
|
|
|
|
* This is serialized with respect to itself by the rules for the
|
|
|
|
* driver above.
|
|
|
|
*/
|
|
|
|
|
|
|
|
static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
|
|
|
|
{
|
|
|
|
unsigned long flags;
|
|
|
|
|
|
|
|
if (tty->raw) {
|
|
|
|
put_tty_queue(c, tty);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (tty->stopped && !tty->flow_stopped &&
|
|
|
|
I_IXON(tty) && I_IXANY(tty)) {
|
|
|
|
start_tty(tty);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (I_ISTRIP(tty))
|
|
|
|
c &= 0x7f;
|
|
|
|
if (I_IUCLC(tty) && L_IEXTEN(tty))
|
|
|
|
c=tolower(c);
|
|
|
|
|
|
|
|
if (tty->closing) {
|
|
|
|
if (I_IXON(tty)) {
|
|
|
|
if (c == START_CHAR(tty))
|
|
|
|
start_tty(tty);
|
|
|
|
else if (c == STOP_CHAR(tty))
|
|
|
|
stop_tty(tty);
|
|
|
|
}
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* If the previous character was LNEXT, or we know that this
|
|
|
|
* character is not one of the characters that we'll have to
|
|
|
|
* handle specially, do shortcut processing to speed things
|
|
|
|
* up.
|
|
|
|
*/
|
|
|
|
if (!test_bit(c, tty->process_char_map) || tty->lnext) {
|
|
|
|
finish_erasing(tty);
|
|
|
|
tty->lnext = 0;
|
|
|
|
if (L_ECHO(tty)) {
|
|
|
|
if (tty->read_cnt >= N_TTY_BUF_SIZE-1) {
|
|
|
|
put_char('\a', tty); /* beep if no space */
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
/* Record the column of first canon char. */
|
|
|
|
if (tty->canon_head == tty->read_head)
|
|
|
|
tty->canon_column = tty->column;
|
|
|
|
echo_char(c, tty);
|
|
|
|
}
|
|
|
|
if (I_PARMRK(tty) && c == (unsigned char) '\377')
|
|
|
|
put_tty_queue(c, tty);
|
|
|
|
put_tty_queue(c, tty);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (c == '\r') {
|
|
|
|
if (I_IGNCR(tty))
|
|
|
|
return;
|
|
|
|
if (I_ICRNL(tty))
|
|
|
|
c = '\n';
|
|
|
|
} else if (c == '\n' && I_INLCR(tty))
|
|
|
|
c = '\r';
|
|
|
|
if (I_IXON(tty)) {
|
|
|
|
if (c == START_CHAR(tty)) {
|
|
|
|
start_tty(tty);
|
|
|
|
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:
|
|
|
|
isig(signal, tty, 0);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
if (tty->icanon) {
|
|
|
|
if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) ||
|
|
|
|
(c == WERASE_CHAR(tty) && L_IEXTEN(tty))) {
|
|
|
|
eraser(c, tty);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) {
|
|
|
|
tty->lnext = 1;
|
|
|
|
if (L_ECHO(tty)) {
|
|
|
|
finish_erasing(tty);
|
|
|
|
if (L_ECHOCTL(tty)) {
|
|
|
|
put_char('^', tty);
|
|
|
|
put_char('\b', tty);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
if (c == REPRINT_CHAR(tty) && L_ECHO(tty) &&
|
|
|
|
L_IEXTEN(tty)) {
|
|
|
|
unsigned long tail = tty->canon_head;
|
|
|
|
|
|
|
|
finish_erasing(tty);
|
|
|
|
echo_char(c, tty);
|
|
|
|
opost('\n', tty);
|
|
|
|
while (tail != tty->read_head) {
|
|
|
|
echo_char(tty->read_buf[tail], tty);
|
|
|
|
tail = (tail+1) & (N_TTY_BUF_SIZE-1);
|
|
|
|
}
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
if (c == '\n') {
|
|
|
|
if (L_ECHO(tty) || L_ECHONL(tty)) {
|
2005-07-07 18:56:55 -06:00
|
|
|
if (tty->read_cnt >= N_TTY_BUF_SIZE-1)
|
2005-04-16 16:20:36 -06:00
|
|
|
put_char('\a', tty);
|
|
|
|
opost('\n', tty);
|
|
|
|
}
|
|
|
|
goto handle_newline;
|
|
|
|
}
|
|
|
|
if (c == EOF_CHAR(tty)) {
|
|
|
|
if (tty->canon_head != tty->read_head)
|
|
|
|
set_bit(TTY_PUSH, &tty->flags);
|
|
|
|
c = __DISABLED_CHAR;
|
|
|
|
goto handle_newline;
|
|
|
|
}
|
|
|
|
if ((c == EOL_CHAR(tty)) ||
|
|
|
|
(c == EOL2_CHAR(tty) && L_IEXTEN(tty))) {
|
|
|
|
/*
|
|
|
|
* XXX are EOL_CHAR and EOL2_CHAR echoed?!?
|
|
|
|
*/
|
|
|
|
if (L_ECHO(tty)) {
|
2005-07-07 18:56:55 -06:00
|
|
|
if (tty->read_cnt >= N_TTY_BUF_SIZE-1)
|
2005-04-16 16:20:36 -06:00
|
|
|
put_char('\a', tty);
|
|
|
|
/* Record the column of first canon char. */
|
|
|
|
if (tty->canon_head == tty->read_head)
|
|
|
|
tty->canon_column = tty->column;
|
|
|
|
echo_char(c, tty);
|
|
|
|
}
|
|
|
|
/*
|
|
|
|
* XXX does PARMRK doubling happen for
|
|
|
|
* EOL_CHAR and EOL2_CHAR?
|
|
|
|
*/
|
|
|
|
if (I_PARMRK(tty) && c == (unsigned char) '\377')
|
|
|
|
put_tty_queue(c, tty);
|
|
|
|
|
|
|
|
handle_newline:
|
|
|
|
spin_lock_irqsave(&tty->read_lock, flags);
|
|
|
|
set_bit(tty->read_head, tty->read_flags);
|
|
|
|
put_tty_queue_nolock(c, tty);
|
|
|
|
tty->canon_head = tty->read_head;
|
|
|
|
tty->canon_data++;
|
|
|
|
spin_unlock_irqrestore(&tty->read_lock, flags);
|
|
|
|
kill_fasync(&tty->fasync, SIGIO, POLL_IN);
|
|
|
|
if (waitqueue_active(&tty->read_wait))
|
|
|
|
wake_up_interruptible(&tty->read_wait);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
finish_erasing(tty);
|
|
|
|
if (L_ECHO(tty)) {
|
|
|
|
if (tty->read_cnt >= N_TTY_BUF_SIZE-1) {
|
|
|
|
put_char('\a', tty); /* beep if no space */
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
if (c == '\n')
|
|
|
|
opost('\n', tty);
|
|
|
|
else {
|
|
|
|
/* Record the column of first canon char. */
|
|
|
|
if (tty->canon_head == tty->read_head)
|
|
|
|
tty->canon_column = tty->column;
|
|
|
|
echo_char(c, tty);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
if (I_PARMRK(tty) && c == (unsigned char) '\377')
|
|
|
|
put_tty_queue(c, tty);
|
|
|
|
|
|
|
|
put_tty_queue(c, tty);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* n_tty_receive_room - receive space
|
|
|
|
* @tty: terminal
|
|
|
|
*
|
|
|
|
* Called by the driver to find out how much data it is
|
|
|
|
* permitted to feed to the line discipline without any being lost
|
|
|
|
* and thus to manage flow control. Not serialized. Answers for the
|
|
|
|
* "instant".
|
|
|
|
*/
|
|
|
|
|
|
|
|
static int n_tty_receive_room(struct tty_struct *tty)
|
|
|
|
{
|
|
|
|
int left = N_TTY_BUF_SIZE - tty->read_cnt - 1;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* If we are doing input canonicalization, and there are no
|
|
|
|
* pending newlines, let characters through without limit, so
|
|
|
|
* that erase characters will be handled. Other excess
|
|
|
|
* characters will be beeped.
|
|
|
|
*/
|
2005-07-07 18:56:55 -06:00
|
|
|
if (left <= 0)
|
|
|
|
left = tty->icanon && !tty->canon_data;
|
|
|
|
return left;
|
2005-04-16 16:20:36 -06:00
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* 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)
|
|
|
|
{
|
|
|
|
set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
|
|
|
|
kill_fasync(&tty->fasync, SIGIO, POLL_OUT);
|
|
|
|
}
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* n_tty_receive_buf - data receive
|
|
|
|
* @tty: terminal device
|
|
|
|
* @cp: buffer
|
|
|
|
* @fp: flag buffer
|
|
|
|
* @count: characters
|
|
|
|
*
|
|
|
|
* Called by the terminal driver when a block of characters has
|
|
|
|
* been received. This function must be called from soft contexts
|
|
|
|
* not from interrupt context. The driver is responsible for making
|
|
|
|
* calls one at a time and in order (or using flush_to_ldisc)
|
|
|
|
*/
|
|
|
|
|
|
|
|
static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
|
|
|
|
char *fp, int count)
|
|
|
|
{
|
|
|
|
const unsigned char *p;
|
|
|
|
char *f, flags = TTY_NORMAL;
|
|
|
|
int i;
|
|
|
|
char buf[64];
|
|
|
|
unsigned long cpuflags;
|
|
|
|
|
|
|
|
if (!tty->read_buf)
|
|
|
|
return;
|
|
|
|
|
|
|
|
if (tty->real_raw) {
|
|
|
|
spin_lock_irqsave(&tty->read_lock, cpuflags);
|
|
|
|
i = min(N_TTY_BUF_SIZE - tty->read_cnt,
|
|
|
|
N_TTY_BUF_SIZE - tty->read_head);
|
|
|
|
i = min(count, i);
|
|
|
|
memcpy(tty->read_buf + tty->read_head, cp, i);
|
|
|
|
tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1);
|
|
|
|
tty->read_cnt += i;
|
|
|
|
cp += i;
|
|
|
|
count -= i;
|
|
|
|
|
|
|
|
i = min(N_TTY_BUF_SIZE - tty->read_cnt,
|
|
|
|
N_TTY_BUF_SIZE - tty->read_head);
|
|
|
|
i = min(count, i);
|
|
|
|
memcpy(tty->read_buf + tty->read_head, cp, i);
|
|
|
|
tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1);
|
|
|
|
tty->read_cnt += i;
|
|
|
|
spin_unlock_irqrestore(&tty->read_lock, cpuflags);
|
|
|
|
} else {
|
|
|
|
for (i=count, p = cp, f = fp; i; i--, p++) {
|
|
|
|
if (f)
|
|
|
|
flags = *f++;
|
|
|
|
switch (flags) {
|
|
|
|
case TTY_NORMAL:
|
|
|
|
n_tty_receive_char(tty, *p);
|
|
|
|
break;
|
|
|
|
case TTY_BREAK:
|
|
|
|
n_tty_receive_break(tty);
|
|
|
|
break;
|
|
|
|
case TTY_PARITY:
|
|
|
|
case TTY_FRAME:
|
|
|
|
n_tty_receive_parity_error(tty, *p);
|
|
|
|
break;
|
|
|
|
case TTY_OVERRUN:
|
|
|
|
n_tty_receive_overrun(tty);
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
printk("%s: unknown flag %d\n",
|
|
|
|
tty_name(tty, buf), flags);
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
if (tty->driver->flush_chars)
|
|
|
|
tty->driver->flush_chars(tty);
|
|
|
|
}
|
|
|
|
|
|
|
|
if (!tty->icanon && (tty->read_cnt >= tty->minimum_to_wake)) {
|
|
|
|
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 (n_tty_receive_room(tty) < TTY_THRESHOLD_THROTTLE) {
|
|
|
|
/* check TTY_THROTTLED first so it indicates our state */
|
|
|
|
if (!test_and_set_bit(TTY_THROTTLED, &tty->flags) &&
|
|
|
|
tty->driver->throttle)
|
|
|
|
tty->driver->throttle(tty);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
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.
|
|
|
|
*/
|
|
|
|
|
|
|
|
static void n_tty_set_termios(struct tty_struct *tty, struct termios * old)
|
|
|
|
{
|
|
|
|
if (!tty)
|
|
|
|
return;
|
|
|
|
|
|
|
|
tty->icanon = (L_ICANON(tty) != 0);
|
|
|
|
if (test_bit(TTY_HW_COOK_IN, &tty->flags)) {
|
|
|
|
tty->raw = 1;
|
|
|
|
tty->real_raw = 1;
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) ||
|
|
|
|
I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) ||
|
|
|
|
I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) ||
|
|
|
|
I_PARMRK(tty)) {
|
|
|
|
memset(tty->process_char_map, 0, 256/8);
|
|
|
|
|
|
|
|
if (I_IGNCR(tty) || I_ICRNL(tty))
|
|
|
|
set_bit('\r', tty->process_char_map);
|
|
|
|
if (I_INLCR(tty))
|
|
|
|
set_bit('\n', tty->process_char_map);
|
|
|
|
|
|
|
|
if (L_ICANON(tty)) {
|
|
|
|
set_bit(ERASE_CHAR(tty), tty->process_char_map);
|
|
|
|
set_bit(KILL_CHAR(tty), tty->process_char_map);
|
|
|
|
set_bit(EOF_CHAR(tty), tty->process_char_map);
|
|
|
|
set_bit('\n', tty->process_char_map);
|
|
|
|
set_bit(EOL_CHAR(tty), tty->process_char_map);
|
|
|
|
if (L_IEXTEN(tty)) {
|
|
|
|
set_bit(WERASE_CHAR(tty),
|
|
|
|
tty->process_char_map);
|
|
|
|
set_bit(LNEXT_CHAR(tty),
|
|
|
|
tty->process_char_map);
|
|
|
|
set_bit(EOL2_CHAR(tty),
|
|
|
|
tty->process_char_map);
|
|
|
|
if (L_ECHO(tty))
|
|
|
|
set_bit(REPRINT_CHAR(tty),
|
|
|
|
tty->process_char_map);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
if (I_IXON(tty)) {
|
|
|
|
set_bit(START_CHAR(tty), tty->process_char_map);
|
|
|
|
set_bit(STOP_CHAR(tty), tty->process_char_map);
|
|
|
|
}
|
|
|
|
if (L_ISIG(tty)) {
|
|
|
|
set_bit(INTR_CHAR(tty), tty->process_char_map);
|
|
|
|
set_bit(QUIT_CHAR(tty), tty->process_char_map);
|
|
|
|
set_bit(SUSP_CHAR(tty), tty->process_char_map);
|
|
|
|
}
|
|
|
|
clear_bit(__DISABLED_CHAR, tty->process_char_map);
|
|
|
|
tty->raw = 0;
|
|
|
|
tty->real_raw = 0;
|
|
|
|
} else {
|
|
|
|
tty->raw = 1;
|
|
|
|
if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) &&
|
|
|
|
(I_IGNPAR(tty) || !I_INPCK(tty)) &&
|
|
|
|
(tty->driver->flags & TTY_DRIVER_REAL_RAW))
|
|
|
|
tty->real_raw = 1;
|
|
|
|
else
|
|
|
|
tty->real_raw = 0;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* n_tty_close - close the ldisc for this tty
|
|
|
|
* @tty: device
|
|
|
|
*
|
|
|
|
* Called from the terminal layer when this line discipline is
|
|
|
|
* being shut down, either because of a close or becsuse of a
|
|
|
|
* discipline change. The function will not be called while other
|
|
|
|
* ldisc methods are in progress.
|
|
|
|
*/
|
|
|
|
|
|
|
|
static void n_tty_close(struct tty_struct *tty)
|
|
|
|
{
|
|
|
|
n_tty_flush_buffer(tty);
|
|
|
|
if (tty->read_buf) {
|
|
|
|
free_buf(tty->read_buf);
|
|
|
|
tty->read_buf = 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)
|
|
|
|
{
|
|
|
|
if (!tty)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
/* This one is ugly. Currently a malloc failure here can panic */
|
|
|
|
if (!tty->read_buf) {
|
|
|
|
tty->read_buf = alloc_buf();
|
|
|
|
if (!tty->read_buf)
|
|
|
|
return -ENOMEM;
|
|
|
|
}
|
|
|
|
memset(tty->read_buf, 0, N_TTY_BUF_SIZE);
|
|
|
|
reset_buffer_flags(tty);
|
|
|
|
tty->column = 0;
|
|
|
|
n_tty_set_termios(tty, NULL);
|
|
|
|
tty->minimum_to_wake = 1;
|
|
|
|
tty->closing = 0;
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline int input_available_p(struct tty_struct *tty, int amt)
|
|
|
|
{
|
|
|
|
if (tty->icanon) {
|
|
|
|
if (tty->canon_data)
|
|
|
|
return 1;
|
|
|
|
} else if (tty->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 read_chan. It is only called when
|
|
|
|
* ICANON is off; it copies characters straight from the tty queue to
|
|
|
|
* user space directly. It can be profitably called twice; once to
|
|
|
|
* drain the space from the tail pointer to the (physical) end of the
|
|
|
|
* buffer, and once to drain the space from the (physical) beginning of
|
|
|
|
* the buffer to head pointer.
|
|
|
|
*
|
|
|
|
* Called under the tty->atomic_read sem and with TTY_DONT_FLIP set
|
|
|
|
*
|
|
|
|
*/
|
|
|
|
|
|
|
|
static inline int copy_from_read_buf(struct tty_struct *tty,
|
|
|
|
unsigned char __user **b,
|
|
|
|
size_t *nr)
|
|
|
|
|
|
|
|
{
|
|
|
|
int retval;
|
|
|
|
size_t n;
|
|
|
|
unsigned long flags;
|
|
|
|
|
|
|
|
retval = 0;
|
|
|
|
spin_lock_irqsave(&tty->read_lock, flags);
|
|
|
|
n = min(tty->read_cnt, N_TTY_BUF_SIZE - tty->read_tail);
|
|
|
|
n = min(*nr, n);
|
|
|
|
spin_unlock_irqrestore(&tty->read_lock, flags);
|
|
|
|
if (n) {
|
|
|
|
mb();
|
|
|
|
retval = copy_to_user(*b, &tty->read_buf[tty->read_tail], n);
|
|
|
|
n -= retval;
|
|
|
|
spin_lock_irqsave(&tty->read_lock, flags);
|
|
|
|
tty->read_tail = (tty->read_tail + n) & (N_TTY_BUF_SIZE-1);
|
|
|
|
tty->read_cnt -= n;
|
|
|
|
spin_unlock_irqrestore(&tty->read_lock, flags);
|
|
|
|
*b += n;
|
|
|
|
*nr -= n;
|
|
|
|
}
|
|
|
|
return retval;
|
|
|
|
}
|
|
|
|
|
|
|
|
extern ssize_t redirected_tty_write(struct file *,const char *,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.
|
|
|
|
*/
|
|
|
|
|
|
|
|
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 <= 0)
|
|
|
|
printk("read_chan: tty->pgrp <= 0!\n");
|
|
|
|
else if (process_group(current) != tty->pgrp) {
|
|
|
|
if (is_ignored(SIGTTIN) ||
|
|
|
|
is_orphaned_pgrp(process_group(current)))
|
|
|
|
return -EIO;
|
|
|
|
kill_pg(process_group(current), SIGTTIN, 1);
|
|
|
|
return -ERESTARTSYS;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
* read_chan - read function for tty
|
|
|
|
* @tty: tty device
|
|
|
|
* @file: file object
|
|
|
|
* @buf: userspace buffer pointer
|
|
|
|
* @nr: size of I/O
|
|
|
|
*
|
|
|
|
* Perform reads for the line discipline. We are guaranteed that the
|
|
|
|
* line discipline will not be closed under us but we may get multiple
|
|
|
|
* parallel readers and must handle this ourselves. We may also get
|
|
|
|
* a hangup. Always called in user context, may sleep.
|
|
|
|
*
|
|
|
|
* This code must be sure never to sleep through a hangup.
|
|
|
|
*/
|
|
|
|
|
|
|
|
static ssize_t read_chan(struct tty_struct *tty, struct file *file,
|
|
|
|
unsigned char __user *buf, size_t nr)
|
|
|
|
{
|
|
|
|
unsigned char __user *b = buf;
|
|
|
|
DECLARE_WAITQUEUE(wait, current);
|
|
|
|
int c;
|
|
|
|
int minimum, time;
|
|
|
|
ssize_t retval = 0;
|
|
|
|
ssize_t size;
|
|
|
|
long timeout;
|
|
|
|
unsigned long flags;
|
|
|
|
|
|
|
|
do_it_again:
|
|
|
|
|
|
|
|
if (!tty->read_buf) {
|
|
|
|
printk("n_tty_read_chan: called with read_buf == NULL?!?\n");
|
|
|
|
return -EIO;
|
|
|
|
}
|
|
|
|
|
|
|
|
c = job_control(tty, file);
|
|
|
|
if(c < 0)
|
|
|
|
return c;
|
|
|
|
|
|
|
|
minimum = time = 0;
|
|
|
|
timeout = MAX_SCHEDULE_TIMEOUT;
|
|
|
|
if (!tty->icanon) {
|
|
|
|
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 (down_trylock(&tty->atomic_read))
|
|
|
|
return -EAGAIN;
|
|
|
|
}
|
|
|
|
else {
|
|
|
|
if (down_interruptible(&tty->atomic_read))
|
|
|
|
return -ERESTARTSYS;
|
|
|
|
}
|
|
|
|
|
|
|
|
add_wait_queue(&tty->read_wait, &wait);
|
|
|
|
set_bit(TTY_DONT_FLIP, &tty->flags);
|
|
|
|
while (nr) {
|
|
|
|
/* First test for status change. */
|
|
|
|
if (tty->packet && tty->link->ctrl_status) {
|
|
|
|
unsigned char cs;
|
|
|
|
if (b != buf)
|
|
|
|
break;
|
|
|
|
cs = tty->link->ctrl_status;
|
|
|
|
tty->link->ctrl_status = 0;
|
|
|
|
if (put_user(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;
|
|
|
|
}
|
|
|
|
clear_bit(TTY_DONT_FLIP, &tty->flags);
|
|
|
|
timeout = schedule_timeout(timeout);
|
|
|
|
set_bit(TTY_DONT_FLIP, &tty->flags);
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
__set_current_state(TASK_RUNNING);
|
|
|
|
|
|
|
|
/* Deal with packet mode. */
|
|
|
|
if (tty->packet && b == buf) {
|
|
|
|
if (put_user(TIOCPKT_DATA, b++)) {
|
|
|
|
retval = -EFAULT;
|
|
|
|
b--;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
nr--;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (tty->icanon) {
|
|
|
|
/* N.B. avoid overrun if nr == 0 */
|
|
|
|
while (nr && tty->read_cnt) {
|
|
|
|
int eol;
|
|
|
|
|
|
|
|
eol = test_and_clear_bit(tty->read_tail,
|
|
|
|
tty->read_flags);
|
|
|
|
c = tty->read_buf[tty->read_tail];
|
|
|
|
spin_lock_irqsave(&tty->read_lock, flags);
|
|
|
|
tty->read_tail = ((tty->read_tail+1) &
|
|
|
|
(N_TTY_BUF_SIZE-1));
|
|
|
|
tty->read_cnt--;
|
|
|
|
if (eol) {
|
|
|
|
/* this test should be redundant:
|
|
|
|
* we shouldn't be reading data if
|
|
|
|
* canon_data is 0
|
|
|
|
*/
|
|
|
|
if (--tty->canon_data < 0)
|
|
|
|
tty->canon_data = 0;
|
|
|
|
}
|
|
|
|
spin_unlock_irqrestore(&tty->read_lock, flags);
|
|
|
|
|
|
|
|
if (!eol || (c != __DISABLED_CHAR)) {
|
|
|
|
if (put_user(c, b++)) {
|
|
|
|
retval = -EFAULT;
|
|
|
|
b--;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
nr--;
|
|
|
|
}
|
|
|
|
if (eol)
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
if (retval)
|
|
|
|
break;
|
|
|
|
} else {
|
|
|
|
int uncopied;
|
|
|
|
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)
|
|
|
|
check_unthrottle(tty);
|
|
|
|
|
|
|
|
if (b - buf >= minimum)
|
|
|
|
break;
|
|
|
|
if (time)
|
|
|
|
timeout = time;
|
|
|
|
}
|
|
|
|
clear_bit(TTY_DONT_FLIP, &tty->flags);
|
|
|
|
up(&tty->atomic_read);
|
|
|
|
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;
|
|
|
|
|
|
|
|
return retval;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* write_chan - write function for tty
|
|
|
|
* @tty: tty device
|
|
|
|
* @file: file object
|
|
|
|
* @buf: userspace buffer pointer
|
|
|
|
* @nr: size of I/O
|
|
|
|
*
|
|
|
|
* Write function of the terminal device. This is serialized with
|
|
|
|
* respect to other write callers but not to termios changes, reads
|
|
|
|
* and other such events. We must be careful with N_TTY as the receive
|
|
|
|
* code will echo characters, thus calling driver write methods.
|
|
|
|
*
|
|
|
|
* This code must be sure never to sleep through a hangup.
|
|
|
|
*/
|
|
|
|
|
|
|
|
static ssize_t write_chan(struct tty_struct * tty, struct file * file,
|
|
|
|
const unsigned char * 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;
|
|
|
|
}
|
|
|
|
|
|
|
|
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 = opost_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 (opost(c, tty) < 0)
|
|
|
|
break;
|
|
|
|
b++; nr--;
|
|
|
|
}
|
|
|
|
if (tty->driver->flush_chars)
|
|
|
|
tty->driver->flush_chars(tty);
|
|
|
|
} else {
|
2005-07-07 18:56:55 -06:00
|
|
|
while (nr > 0) {
|
|
|
|
c = tty->driver->write(tty, b, nr);
|
|
|
|
if (c < 0) {
|
|
|
|
retval = c;
|
|
|
|
goto break_out;
|
|
|
|
}
|
|
|
|
if (!c)
|
|
|
|
break;
|
|
|
|
b += c;
|
|
|
|
nr -= c;
|
2005-04-16 16:20:36 -06:00
|
|
|
}
|
|
|
|
}
|
|
|
|
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);
|
|
|
|
return (b - buf) ? b - buf : retval;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* normal_poll - poll method for N_TTY
|
|
|
|
* @tty: terminal device
|
|
|
|
* @file: file accessing it
|
|
|
|
* @wait: poll table
|
|
|
|
*
|
|
|
|
* Called when the line discipline is asked to poll() for data or
|
|
|
|
* for special events. This code is not serialized with respect to
|
|
|
|
* other events save open/close.
|
|
|
|
*
|
|
|
|
* This code must be sure never to sleep through a hangup.
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* Called without the kernel lock held - fine
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*
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* FIXME: if someone changes the VMIN or discipline settings for the
|
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* terminal while another process is in poll() the poll does not
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* recompute the new limits. Possibly set_termios should issue
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|
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* a read wakeup to fix this bug.
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*/
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static unsigned int normal_poll(struct tty_struct * tty, struct file * file, poll_table *wait)
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|
{
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unsigned int mask = 0;
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|
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poll_wait(file, &tty->read_wait, wait);
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poll_wait(file, &tty->write_wait, wait);
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if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty)))
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|
|
mask |= POLLIN | POLLRDNORM;
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|
|
|
if (tty->packet && tty->link->ctrl_status)
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|
|
mask |= POLLPRI | POLLIN | POLLRDNORM;
|
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|
|
if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
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|
|
|
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->driver->chars_in_buffer(tty) < WAKEUP_CHARS &&
|
|
|
|
tty->driver->write_room(tty) > 0)
|
|
|
|
mask |= POLLOUT | POLLWRNORM;
|
|
|
|
return mask;
|
|
|
|
}
|
|
|
|
|
|
|
|
struct tty_ldisc tty_ldisc_N_TTY = {
|
|
|
|
TTY_LDISC_MAGIC, /* magic */
|
|
|
|
"n_tty", /* name */
|
|
|
|
0, /* num */
|
|
|
|
0, /* flags */
|
|
|
|
n_tty_open, /* open */
|
|
|
|
n_tty_close, /* close */
|
|
|
|
n_tty_flush_buffer, /* flush_buffer */
|
|
|
|
n_tty_chars_in_buffer, /* chars_in_buffer */
|
|
|
|
read_chan, /* read */
|
|
|
|
write_chan, /* write */
|
|
|
|
n_tty_ioctl, /* ioctl */
|
|
|
|
n_tty_set_termios, /* set_termios */
|
|
|
|
normal_poll, /* poll */
|
|
|
|
NULL, /* hangup */
|
|
|
|
n_tty_receive_buf, /* receive_buf */
|
|
|
|
n_tty_receive_room, /* receive_room */
|
|
|
|
n_tty_write_wakeup /* write_wakeup */
|
|
|
|
};
|
|
|
|
|