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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-15 17:56:42 +07:00
0f40fbbcc3
OpenSSH expects the (non-blocking) read() of pty master to return EAGAIN only if it has received all of the slave-side output after it has received SIGCHLD. This used to work on pre-3.12 kernels. This fix effectively forces non-blocking read() and poll() to block for parallel i/o to complete for all ttys. It also unwinds these changes: 1)f8747d4a46
tty: Fix pty master read() after slave closes 2)52bce7f8d4
pty, n_tty: Simplify input processing on final close 3)1a48632ffe
pty: Fix input race when closing Inspired by analysis and patch from Marc Aurele La France <tsi@tuyoix.net> Reported-by: Volth <openssh@volth.com> Reported-by: Marc Aurele La France <tsi@tuyoix.net> BugLink: https://bugzilla.mindrot.org/show_bug.cgi?id=52 BugLink: https://bugzilla.mindrot.org/show_bug.cgi?id=2492 Signed-off-by: Brian Bloniarz <brian.bloniarz@gmail.com> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2476 lines
61 KiB
C
2476 lines
61 KiB
C
/*
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* n_tty.c --- implements the N_TTY line discipline.
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*
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* This code used to be in tty_io.c, but things are getting hairy
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* enough that it made sense to split things off. (The N_TTY
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* processing has changed so much that it's hardly recognizable,
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* anyway...)
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*
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* Note that the open routine for N_TTY is guaranteed never to return
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* an error. This is because Linux will fall back to setting a line
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* to N_TTY if it can not switch to any other line discipline.
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*
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* Written by Theodore Ts'o, Copyright 1994.
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*
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* This file also contains code originally written by Linus Torvalds,
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* Copyright 1991, 1992, 1993, and by Julian Cowley, Copyright 1994.
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*
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* This file may be redistributed under the terms of the GNU General Public
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* License.
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*
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* Reduced memory usage for older ARM systems - Russell King.
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*
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* 2000/01/20 Fixed SMP locking on put_tty_queue using bits of
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* the patch by Andrew J. Kroll <ag784@freenet.buffalo.edu>
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* who actually finally proved there really was a race.
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*
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* 2002/03/18 Implemented n_tty_wakeup to send SIGIO POLL_OUTs to
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* waiting writing processes-Sapan Bhatia <sapan@corewars.org>.
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* Also fixed a bug in BLOCKING mode where n_tty_write returns
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* EAGAIN
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*/
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#include <linux/types.h>
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#include <linux/major.h>
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#include <linux/errno.h>
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#include <linux/signal.h>
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#include <linux/fcntl.h>
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#include <linux/sched.h>
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#include <linux/interrupt.h>
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#include <linux/tty.h>
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#include <linux/timer.h>
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#include <linux/ctype.h>
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#include <linux/mm.h>
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#include <linux/string.h>
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#include <linux/slab.h>
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#include <linux/poll.h>
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#include <linux/bitops.h>
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#include <linux/audit.h>
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#include <linux/file.h>
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#include <linux/uaccess.h>
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#include <linux/module.h>
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#include <linux/ratelimit.h>
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#include <linux/vmalloc.h>
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/* number of characters left in xmit buffer before select has we have room */
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#define WAKEUP_CHARS 256
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/*
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* This defines the low- and high-watermarks for throttling and
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* unthrottling the TTY driver. These watermarks are used for
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* controlling the space in the read buffer.
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*/
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#define TTY_THRESHOLD_THROTTLE 128 /* now based on remaining room */
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#define TTY_THRESHOLD_UNTHROTTLE 128
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/*
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* Special byte codes used in the echo buffer to represent operations
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* or special handling of characters. Bytes in the echo buffer that
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* are not part of such special blocks are treated as normal character
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* codes.
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*/
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#define ECHO_OP_START 0xff
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#define ECHO_OP_MOVE_BACK_COL 0x80
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#define ECHO_OP_SET_CANON_COL 0x81
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#define ECHO_OP_ERASE_TAB 0x82
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#define ECHO_COMMIT_WATERMARK 256
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#define ECHO_BLOCK 256
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#define ECHO_DISCARD_WATERMARK N_TTY_BUF_SIZE - (ECHO_BLOCK + 32)
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#undef N_TTY_TRACE
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#ifdef N_TTY_TRACE
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# define n_tty_trace(f, args...) trace_printk(f, ##args)
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#else
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# define n_tty_trace(f, args...)
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#endif
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struct n_tty_data {
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/* producer-published */
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size_t read_head;
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size_t commit_head;
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size_t canon_head;
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size_t echo_head;
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size_t echo_commit;
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size_t echo_mark;
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DECLARE_BITMAP(char_map, 256);
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/* private to n_tty_receive_overrun (single-threaded) */
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unsigned long overrun_time;
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int num_overrun;
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/* non-atomic */
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bool no_room;
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/* must hold exclusive termios_rwsem to reset these */
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unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1;
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unsigned char push:1;
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/* shared by producer and consumer */
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char read_buf[N_TTY_BUF_SIZE];
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DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE);
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unsigned char echo_buf[N_TTY_BUF_SIZE];
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/* consumer-published */
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size_t read_tail;
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size_t line_start;
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/* protected by output lock */
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unsigned int column;
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unsigned int canon_column;
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size_t echo_tail;
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struct mutex atomic_read_lock;
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struct mutex output_lock;
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};
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static inline size_t read_cnt(struct n_tty_data *ldata)
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{
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return ldata->read_head - ldata->read_tail;
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}
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static inline unsigned char read_buf(struct n_tty_data *ldata, size_t i)
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{
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return ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)];
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}
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static inline unsigned char *read_buf_addr(struct n_tty_data *ldata, size_t i)
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{
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return &ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)];
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}
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static inline unsigned char echo_buf(struct n_tty_data *ldata, size_t i)
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{
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return ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)];
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}
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static inline unsigned char *echo_buf_addr(struct n_tty_data *ldata, size_t i)
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{
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return &ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)];
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}
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static int tty_copy_to_user(struct tty_struct *tty, void __user *to,
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size_t tail, size_t n)
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{
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struct n_tty_data *ldata = tty->disc_data;
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size_t size = N_TTY_BUF_SIZE - tail;
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const void *from = read_buf_addr(ldata, tail);
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int uncopied;
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if (n > size) {
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tty_audit_add_data(tty, from, size);
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uncopied = copy_to_user(to, from, size);
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if (uncopied)
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return uncopied;
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to += size;
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n -= size;
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from = ldata->read_buf;
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}
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tty_audit_add_data(tty, from, n);
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return copy_to_user(to, from, n);
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}
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/**
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* n_tty_kick_worker - start input worker (if required)
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* @tty: terminal
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*
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* Re-schedules the flip buffer work if it may have stopped
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*
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* Caller holds exclusive termios_rwsem
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* or
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* n_tty_read()/consumer path:
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* holds non-exclusive termios_rwsem
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*/
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static void n_tty_kick_worker(struct tty_struct *tty)
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{
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struct n_tty_data *ldata = tty->disc_data;
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/* Did the input worker stop? Restart it */
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if (unlikely(ldata->no_room)) {
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ldata->no_room = 0;
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WARN_RATELIMIT(tty->port->itty == NULL,
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"scheduling with invalid itty\n");
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/* see if ldisc has been killed - if so, this means that
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* even though the ldisc has been halted and ->buf.work
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* cancelled, ->buf.work is about to be rescheduled
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*/
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WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags),
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"scheduling buffer work for halted ldisc\n");
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tty_buffer_restart_work(tty->port);
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}
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}
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static ssize_t chars_in_buffer(struct tty_struct *tty)
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{
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struct n_tty_data *ldata = tty->disc_data;
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ssize_t n = 0;
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if (!ldata->icanon)
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n = ldata->commit_head - ldata->read_tail;
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else
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n = ldata->canon_head - ldata->read_tail;
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return n;
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}
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/**
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* n_tty_write_wakeup - asynchronous I/O notifier
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* @tty: tty device
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*
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* Required for the ptys, serial driver etc. since processes
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* that attach themselves to the master and rely on ASYNC
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* IO must be woken up
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*/
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static void n_tty_write_wakeup(struct tty_struct *tty)
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{
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clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
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kill_fasync(&tty->fasync, SIGIO, POLL_OUT);
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}
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static void n_tty_check_throttle(struct tty_struct *tty)
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{
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struct n_tty_data *ldata = tty->disc_data;
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/*
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* Check the remaining room for the input canonicalization
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* mode. We don't want to throttle the driver if we're in
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* canonical mode and don't have a newline yet!
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*/
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if (ldata->icanon && ldata->canon_head == ldata->read_tail)
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return;
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while (1) {
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int throttled;
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tty_set_flow_change(tty, TTY_THROTTLE_SAFE);
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if (N_TTY_BUF_SIZE - read_cnt(ldata) >= TTY_THRESHOLD_THROTTLE)
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break;
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throttled = tty_throttle_safe(tty);
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if (!throttled)
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break;
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}
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__tty_set_flow_change(tty, 0);
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}
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static void n_tty_check_unthrottle(struct tty_struct *tty)
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{
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if (tty->driver->type == TTY_DRIVER_TYPE_PTY) {
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if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE)
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return;
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n_tty_kick_worker(tty);
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tty_wakeup(tty->link);
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return;
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}
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/* If there is enough space in the read buffer now, let the
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* low-level driver know. We use chars_in_buffer() to
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* check the buffer, as it now knows about canonical mode.
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* Otherwise, if the driver is throttled and the line is
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* longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode,
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* we won't get any more characters.
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*/
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while (1) {
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int unthrottled;
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tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE);
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if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE)
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break;
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n_tty_kick_worker(tty);
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unthrottled = tty_unthrottle_safe(tty);
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if (!unthrottled)
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break;
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}
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__tty_set_flow_change(tty, 0);
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}
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/**
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* put_tty_queue - add character to tty
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* @c: character
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* @ldata: n_tty data
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*
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* Add a character to the tty read_buf queue.
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*
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* n_tty_receive_buf()/producer path:
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* caller holds non-exclusive termios_rwsem
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*/
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static inline void put_tty_queue(unsigned char c, struct n_tty_data *ldata)
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{
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*read_buf_addr(ldata, ldata->read_head) = c;
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ldata->read_head++;
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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 and clear the flags.
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* Called from n_tty_open() and n_tty_flush_buffer().
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*
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* Locking: caller holds exclusive termios_rwsem
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* (or locking is not required)
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*/
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static void reset_buffer_flags(struct n_tty_data *ldata)
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{
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ldata->read_head = ldata->canon_head = ldata->read_tail = 0;
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ldata->echo_head = ldata->echo_tail = ldata->echo_commit = 0;
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ldata->commit_head = 0;
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ldata->echo_mark = 0;
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ldata->line_start = 0;
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ldata->erasing = 0;
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bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE);
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ldata->push = 0;
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}
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static void n_tty_packet_mode_flush(struct tty_struct *tty)
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{
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unsigned long flags;
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if (tty->link->packet) {
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spin_lock_irqsave(&tty->ctrl_lock, flags);
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tty->ctrl_status |= TIOCPKT_FLUSHREAD;
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spin_unlock_irqrestore(&tty->ctrl_lock, flags);
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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_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 tty layer wants the
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* buffer flushed (eg at hangup) or when the N_TTY line discipline
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* internally has to clean the pending queue (for example some signals).
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*
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* Holds termios_rwsem to exclude producer/consumer while
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* buffer indices are reset.
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*
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* Locking: ctrl_lock, exclusive termios_rwsem
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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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down_write(&tty->termios_rwsem);
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reset_buffer_flags(tty->disc_data);
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n_tty_kick_worker(tty);
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if (tty->link)
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n_tty_packet_mode_flush(tty);
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up_write(&tty->termios_rwsem);
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}
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/**
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* is_utf8_continuation - utf8 multibyte check
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* @c: byte to check
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*
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* Returns true if the utf8 character 'c' is a multibyte continuation
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* character. We use this to correctly compute the on screen size
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* of the character when printing
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*/
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static inline int is_utf8_continuation(unsigned char c)
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{
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return (c & 0xc0) == 0x80;
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}
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/**
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* is_continuation - multibyte check
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* @c: byte to check
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*
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* Returns true if the utf8 character 'c' is a multibyte continuation
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* character and the terminal is in unicode mode.
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*/
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static inline int is_continuation(unsigned char c, struct tty_struct *tty)
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{
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return I_IUTF8(tty) && is_utf8_continuation(c);
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}
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/**
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* do_output_char - output one character
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* @c: character (or partial unicode symbol)
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* @tty: terminal device
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* @space: space available in tty driver write buffer
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*
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* This is a helper function that handles one output character
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* (including special characters like TAB, CR, LF, etc.),
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* doing OPOST processing and putting the results in the
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* tty driver's write buffer.
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*
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* Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY
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* and NLDLY. They simply aren't relevant in the world today.
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* If you ever need them, add them here.
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*
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* Returns the number of bytes of buffer space used or -1 if
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* no space left.
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*
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* Locking: should be called under the output_lock to protect
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* the column state and space left in the buffer
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*/
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static int do_output_char(unsigned char c, struct tty_struct *tty, int space)
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{
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struct n_tty_data *ldata = tty->disc_data;
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int spaces;
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if (!space)
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return -1;
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switch (c) {
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case '\n':
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if (O_ONLRET(tty))
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ldata->column = 0;
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if (O_ONLCR(tty)) {
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if (space < 2)
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return -1;
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ldata->canon_column = ldata->column = 0;
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tty->ops->write(tty, "\r\n", 2);
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return 2;
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}
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ldata->canon_column = ldata->column;
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break;
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case '\r':
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if (O_ONOCR(tty) && ldata->column == 0)
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return 0;
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if (O_OCRNL(tty)) {
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c = '\n';
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if (O_ONLRET(tty))
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ldata->canon_column = ldata->column = 0;
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break;
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}
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ldata->canon_column = ldata->column = 0;
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break;
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case '\t':
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spaces = 8 - (ldata->column & 7);
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if (O_TABDLY(tty) == XTABS) {
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if (space < spaces)
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return -1;
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ldata->column += spaces;
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tty->ops->write(tty, " ", spaces);
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return spaces;
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}
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ldata->column += spaces;
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break;
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case '\b':
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if (ldata->column > 0)
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ldata->column--;
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break;
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default:
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if (!iscntrl(c)) {
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if (O_OLCUC(tty))
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c = toupper(c);
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if (!is_continuation(c, tty))
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ldata->column++;
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}
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break;
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}
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tty_put_char(tty, c);
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return 1;
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}
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/**
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* process_output - output post processor
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* @c: character (or partial unicode symbol)
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* @tty: terminal device
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*
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* Output one character with OPOST processing.
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* Returns -1 when the output device is full and the character
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* must be retried.
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*
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* Locking: output_lock to protect column state and space left
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* (also, this is called from n_tty_write under the
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* tty layer write lock)
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*/
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|
static int process_output(unsigned char c, struct tty_struct *tty)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
int space, retval;
|
|
|
|
mutex_lock(&ldata->output_lock);
|
|
|
|
space = tty_write_room(tty);
|
|
retval = do_output_char(c, tty, space);
|
|
|
|
mutex_unlock(&ldata->output_lock);
|
|
if (retval < 0)
|
|
return -1;
|
|
else
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* process_output_block - block post processor
|
|
* @tty: terminal device
|
|
* @buf: character buffer
|
|
* @nr: number of bytes to output
|
|
*
|
|
* Output a block of characters with OPOST processing.
|
|
* Returns the number of characters output.
|
|
*
|
|
* This path is used to speed up block console writes, among other
|
|
* things when processing blocks of output data. It handles only
|
|
* the simple cases normally found and helps to generate blocks of
|
|
* symbols for the console driver and thus improve performance.
|
|
*
|
|
* Locking: output_lock to protect column state and space left
|
|
* (also, this is called from n_tty_write under the
|
|
* tty layer write lock)
|
|
*/
|
|
|
|
static ssize_t process_output_block(struct tty_struct *tty,
|
|
const unsigned char *buf, unsigned int nr)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
int space;
|
|
int i;
|
|
const unsigned char *cp;
|
|
|
|
mutex_lock(&ldata->output_lock);
|
|
|
|
space = tty_write_room(tty);
|
|
if (!space) {
|
|
mutex_unlock(&ldata->output_lock);
|
|
return 0;
|
|
}
|
|
if (nr > space)
|
|
nr = space;
|
|
|
|
for (i = 0, cp = buf; i < nr; i++, cp++) {
|
|
unsigned char c = *cp;
|
|
|
|
switch (c) {
|
|
case '\n':
|
|
if (O_ONLRET(tty))
|
|
ldata->column = 0;
|
|
if (O_ONLCR(tty))
|
|
goto break_out;
|
|
ldata->canon_column = ldata->column;
|
|
break;
|
|
case '\r':
|
|
if (O_ONOCR(tty) && ldata->column == 0)
|
|
goto break_out;
|
|
if (O_OCRNL(tty))
|
|
goto break_out;
|
|
ldata->canon_column = ldata->column = 0;
|
|
break;
|
|
case '\t':
|
|
goto break_out;
|
|
case '\b':
|
|
if (ldata->column > 0)
|
|
ldata->column--;
|
|
break;
|
|
default:
|
|
if (!iscntrl(c)) {
|
|
if (O_OLCUC(tty))
|
|
goto break_out;
|
|
if (!is_continuation(c, tty))
|
|
ldata->column++;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
break_out:
|
|
i = tty->ops->write(tty, buf, i);
|
|
|
|
mutex_unlock(&ldata->output_lock);
|
|
return i;
|
|
}
|
|
|
|
/**
|
|
* process_echoes - write pending echo characters
|
|
* @tty: terminal device
|
|
*
|
|
* Write previously buffered echo (and other ldisc-generated)
|
|
* characters to the tty.
|
|
*
|
|
* Characters generated by the ldisc (including echoes) need to
|
|
* be buffered because the driver's write buffer can fill during
|
|
* heavy program output. Echoing straight to the driver will
|
|
* often fail under these conditions, causing lost characters and
|
|
* resulting mismatches of ldisc state information.
|
|
*
|
|
* Since the ldisc state must represent the characters actually sent
|
|
* to the driver at the time of the write, operations like certain
|
|
* changes in column state are also saved in the buffer and executed
|
|
* here.
|
|
*
|
|
* A circular fifo buffer is used so that the most recent characters
|
|
* are prioritized. Also, when control characters are echoed with a
|
|
* prefixed "^", the pair is treated atomically and thus not separated.
|
|
*
|
|
* Locking: callers must hold output_lock
|
|
*/
|
|
|
|
static size_t __process_echoes(struct tty_struct *tty)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
int space, old_space;
|
|
size_t tail;
|
|
unsigned char c;
|
|
|
|
old_space = space = tty_write_room(tty);
|
|
|
|
tail = ldata->echo_tail;
|
|
while (ldata->echo_commit != tail) {
|
|
c = echo_buf(ldata, tail);
|
|
if (c == ECHO_OP_START) {
|
|
unsigned char op;
|
|
int no_space_left = 0;
|
|
|
|
/*
|
|
* If the buffer byte is the start of a multi-byte
|
|
* operation, get the next byte, which is either the
|
|
* op code or a control character value.
|
|
*/
|
|
op = echo_buf(ldata, tail + 1);
|
|
|
|
switch (op) {
|
|
unsigned int num_chars, num_bs;
|
|
|
|
case ECHO_OP_ERASE_TAB:
|
|
num_chars = echo_buf(ldata, tail + 2);
|
|
|
|
/*
|
|
* Determine how many columns to go back
|
|
* in order to erase the tab.
|
|
* This depends on the number of columns
|
|
* used by other characters within the tab
|
|
* area. If this (modulo 8) count is from
|
|
* the start of input rather than from a
|
|
* previous tab, we offset by canon column.
|
|
* Otherwise, tab spacing is normal.
|
|
*/
|
|
if (!(num_chars & 0x80))
|
|
num_chars += ldata->canon_column;
|
|
num_bs = 8 - (num_chars & 7);
|
|
|
|
if (num_bs > space) {
|
|
no_space_left = 1;
|
|
break;
|
|
}
|
|
space -= num_bs;
|
|
while (num_bs--) {
|
|
tty_put_char(tty, '\b');
|
|
if (ldata->column > 0)
|
|
ldata->column--;
|
|
}
|
|
tail += 3;
|
|
break;
|
|
|
|
case ECHO_OP_SET_CANON_COL:
|
|
ldata->canon_column = ldata->column;
|
|
tail += 2;
|
|
break;
|
|
|
|
case ECHO_OP_MOVE_BACK_COL:
|
|
if (ldata->column > 0)
|
|
ldata->column--;
|
|
tail += 2;
|
|
break;
|
|
|
|
case ECHO_OP_START:
|
|
/* This is an escaped echo op start code */
|
|
if (!space) {
|
|
no_space_left = 1;
|
|
break;
|
|
}
|
|
tty_put_char(tty, ECHO_OP_START);
|
|
ldata->column++;
|
|
space--;
|
|
tail += 2;
|
|
break;
|
|
|
|
default:
|
|
/*
|
|
* If the op is not a special byte code,
|
|
* it is a ctrl char tagged to be echoed
|
|
* as "^X" (where X is the letter
|
|
* representing the control char).
|
|
* Note that we must ensure there is
|
|
* enough space for the whole ctrl pair.
|
|
*
|
|
*/
|
|
if (space < 2) {
|
|
no_space_left = 1;
|
|
break;
|
|
}
|
|
tty_put_char(tty, '^');
|
|
tty_put_char(tty, op ^ 0100);
|
|
ldata->column += 2;
|
|
space -= 2;
|
|
tail += 2;
|
|
}
|
|
|
|
if (no_space_left)
|
|
break;
|
|
} else {
|
|
if (O_OPOST(tty)) {
|
|
int retval = do_output_char(c, tty, space);
|
|
if (retval < 0)
|
|
break;
|
|
space -= retval;
|
|
} else {
|
|
if (!space)
|
|
break;
|
|
tty_put_char(tty, c);
|
|
space -= 1;
|
|
}
|
|
tail += 1;
|
|
}
|
|
}
|
|
|
|
/* If the echo buffer is nearly full (so that the possibility exists
|
|
* of echo overrun before the next commit), then discard enough
|
|
* data at the tail to prevent a subsequent overrun */
|
|
while (ldata->echo_commit - tail >= ECHO_DISCARD_WATERMARK) {
|
|
if (echo_buf(ldata, tail) == ECHO_OP_START) {
|
|
if (echo_buf(ldata, tail + 1) == ECHO_OP_ERASE_TAB)
|
|
tail += 3;
|
|
else
|
|
tail += 2;
|
|
} else
|
|
tail++;
|
|
}
|
|
|
|
ldata->echo_tail = tail;
|
|
return old_space - space;
|
|
}
|
|
|
|
static void commit_echoes(struct tty_struct *tty)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
size_t nr, old, echoed;
|
|
size_t head;
|
|
|
|
head = ldata->echo_head;
|
|
ldata->echo_mark = head;
|
|
old = ldata->echo_commit - ldata->echo_tail;
|
|
|
|
/* Process committed echoes if the accumulated # of bytes
|
|
* is over the threshold (and try again each time another
|
|
* block is accumulated) */
|
|
nr = head - ldata->echo_tail;
|
|
if (nr < ECHO_COMMIT_WATERMARK || (nr % ECHO_BLOCK > old % ECHO_BLOCK))
|
|
return;
|
|
|
|
mutex_lock(&ldata->output_lock);
|
|
ldata->echo_commit = head;
|
|
echoed = __process_echoes(tty);
|
|
mutex_unlock(&ldata->output_lock);
|
|
|
|
if (echoed && tty->ops->flush_chars)
|
|
tty->ops->flush_chars(tty);
|
|
}
|
|
|
|
static void process_echoes(struct tty_struct *tty)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
size_t echoed;
|
|
|
|
if (ldata->echo_mark == ldata->echo_tail)
|
|
return;
|
|
|
|
mutex_lock(&ldata->output_lock);
|
|
ldata->echo_commit = ldata->echo_mark;
|
|
echoed = __process_echoes(tty);
|
|
mutex_unlock(&ldata->output_lock);
|
|
|
|
if (echoed && tty->ops->flush_chars)
|
|
tty->ops->flush_chars(tty);
|
|
}
|
|
|
|
/* NB: echo_mark and echo_head should be equivalent here */
|
|
static void flush_echoes(struct tty_struct *tty)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
|
|
if ((!L_ECHO(tty) && !L_ECHONL(tty)) ||
|
|
ldata->echo_commit == ldata->echo_head)
|
|
return;
|
|
|
|
mutex_lock(&ldata->output_lock);
|
|
ldata->echo_commit = ldata->echo_head;
|
|
__process_echoes(tty);
|
|
mutex_unlock(&ldata->output_lock);
|
|
}
|
|
|
|
/**
|
|
* add_echo_byte - add a byte to the echo buffer
|
|
* @c: unicode byte to echo
|
|
* @ldata: n_tty data
|
|
*
|
|
* Add a character or operation byte to the echo buffer.
|
|
*/
|
|
|
|
static inline void add_echo_byte(unsigned char c, struct n_tty_data *ldata)
|
|
{
|
|
*echo_buf_addr(ldata, ldata->echo_head++) = c;
|
|
}
|
|
|
|
/**
|
|
* echo_move_back_col - add operation to move back a column
|
|
* @ldata: n_tty data
|
|
*
|
|
* Add an operation to the echo buffer to move back one column.
|
|
*/
|
|
|
|
static void echo_move_back_col(struct n_tty_data *ldata)
|
|
{
|
|
add_echo_byte(ECHO_OP_START, ldata);
|
|
add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata);
|
|
}
|
|
|
|
/**
|
|
* echo_set_canon_col - add operation to set the canon column
|
|
* @ldata: n_tty data
|
|
*
|
|
* Add an operation to the echo buffer to set the canon column
|
|
* to the current column.
|
|
*/
|
|
|
|
static void echo_set_canon_col(struct n_tty_data *ldata)
|
|
{
|
|
add_echo_byte(ECHO_OP_START, ldata);
|
|
add_echo_byte(ECHO_OP_SET_CANON_COL, ldata);
|
|
}
|
|
|
|
/**
|
|
* echo_erase_tab - add operation to erase a tab
|
|
* @num_chars: number of character columns already used
|
|
* @after_tab: true if num_chars starts after a previous tab
|
|
* @ldata: n_tty data
|
|
*
|
|
* Add an operation to the echo buffer to erase a tab.
|
|
*
|
|
* Called by the eraser function, which knows how many character
|
|
* columns have been used since either a previous tab or the start
|
|
* of input. This information will be used later, along with
|
|
* canon column (if applicable), to go back the correct number
|
|
* of columns.
|
|
*/
|
|
|
|
static void echo_erase_tab(unsigned int num_chars, int after_tab,
|
|
struct n_tty_data *ldata)
|
|
{
|
|
add_echo_byte(ECHO_OP_START, ldata);
|
|
add_echo_byte(ECHO_OP_ERASE_TAB, ldata);
|
|
|
|
/* We only need to know this modulo 8 (tab spacing) */
|
|
num_chars &= 7;
|
|
|
|
/* Set the high bit as a flag if num_chars is after a previous tab */
|
|
if (after_tab)
|
|
num_chars |= 0x80;
|
|
|
|
add_echo_byte(num_chars, ldata);
|
|
}
|
|
|
|
/**
|
|
* echo_char_raw - echo a character raw
|
|
* @c: unicode byte to echo
|
|
* @tty: terminal device
|
|
*
|
|
* Echo user input back onto the screen. This must be called only when
|
|
* L_ECHO(tty) is true. Called from the driver receive_buf path.
|
|
*
|
|
* This variant does not treat control characters specially.
|
|
*/
|
|
|
|
static void echo_char_raw(unsigned char c, struct n_tty_data *ldata)
|
|
{
|
|
if (c == ECHO_OP_START) {
|
|
add_echo_byte(ECHO_OP_START, ldata);
|
|
add_echo_byte(ECHO_OP_START, ldata);
|
|
} else {
|
|
add_echo_byte(c, ldata);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* echo_char - echo a character
|
|
* @c: unicode byte to echo
|
|
* @tty: terminal device
|
|
*
|
|
* Echo user input back onto the screen. This must be called only when
|
|
* L_ECHO(tty) is true. Called from the driver receive_buf path.
|
|
*
|
|
* This variant tags control characters to be echoed as "^X"
|
|
* (where X is the letter representing the control char).
|
|
*/
|
|
|
|
static void echo_char(unsigned char c, struct tty_struct *tty)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
|
|
if (c == ECHO_OP_START) {
|
|
add_echo_byte(ECHO_OP_START, ldata);
|
|
add_echo_byte(ECHO_OP_START, ldata);
|
|
} else {
|
|
if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t')
|
|
add_echo_byte(ECHO_OP_START, ldata);
|
|
add_echo_byte(c, ldata);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* finish_erasing - complete erase
|
|
* @ldata: n_tty data
|
|
*/
|
|
|
|
static inline void finish_erasing(struct n_tty_data *ldata)
|
|
{
|
|
if (ldata->erasing) {
|
|
echo_char_raw('/', ldata);
|
|
ldata->erasing = 0;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* eraser - handle erase function
|
|
* @c: character input
|
|
* @tty: terminal device
|
|
*
|
|
* Perform erase and necessary output when an erase character is
|
|
* present in the stream from the driver layer. Handles the complexities
|
|
* of UTF-8 multibyte symbols.
|
|
*
|
|
* n_tty_receive_buf()/producer path:
|
|
* caller holds non-exclusive termios_rwsem
|
|
*/
|
|
|
|
static void eraser(unsigned char c, struct tty_struct *tty)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
enum { ERASE, WERASE, KILL } kill_type;
|
|
size_t head;
|
|
size_t cnt;
|
|
int seen_alnums;
|
|
|
|
if (ldata->read_head == ldata->canon_head) {
|
|
/* process_output('\a', tty); */ /* what do you think? */
|
|
return;
|
|
}
|
|
if (c == ERASE_CHAR(tty))
|
|
kill_type = ERASE;
|
|
else if (c == WERASE_CHAR(tty))
|
|
kill_type = WERASE;
|
|
else {
|
|
if (!L_ECHO(tty)) {
|
|
ldata->read_head = ldata->canon_head;
|
|
return;
|
|
}
|
|
if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) {
|
|
ldata->read_head = ldata->canon_head;
|
|
finish_erasing(ldata);
|
|
echo_char(KILL_CHAR(tty), tty);
|
|
/* Add a newline if ECHOK is on and ECHOKE is off. */
|
|
if (L_ECHOK(tty))
|
|
echo_char_raw('\n', ldata);
|
|
return;
|
|
}
|
|
kill_type = KILL;
|
|
}
|
|
|
|
seen_alnums = 0;
|
|
while (ldata->read_head != ldata->canon_head) {
|
|
head = ldata->read_head;
|
|
|
|
/* erase a single possibly multibyte character */
|
|
do {
|
|
head--;
|
|
c = read_buf(ldata, head);
|
|
} while (is_continuation(c, tty) && head != ldata->canon_head);
|
|
|
|
/* do not partially erase */
|
|
if (is_continuation(c, tty))
|
|
break;
|
|
|
|
if (kill_type == WERASE) {
|
|
/* Equivalent to BSD's ALTWERASE. */
|
|
if (isalnum(c) || c == '_')
|
|
seen_alnums++;
|
|
else if (seen_alnums)
|
|
break;
|
|
}
|
|
cnt = ldata->read_head - head;
|
|
ldata->read_head = head;
|
|
if (L_ECHO(tty)) {
|
|
if (L_ECHOPRT(tty)) {
|
|
if (!ldata->erasing) {
|
|
echo_char_raw('\\', ldata);
|
|
ldata->erasing = 1;
|
|
}
|
|
/* if cnt > 1, output a multi-byte character */
|
|
echo_char(c, tty);
|
|
while (--cnt > 0) {
|
|
head++;
|
|
echo_char_raw(read_buf(ldata, head), ldata);
|
|
echo_move_back_col(ldata);
|
|
}
|
|
} else if (kill_type == ERASE && !L_ECHOE(tty)) {
|
|
echo_char(ERASE_CHAR(tty), tty);
|
|
} else if (c == '\t') {
|
|
unsigned int num_chars = 0;
|
|
int after_tab = 0;
|
|
size_t tail = ldata->read_head;
|
|
|
|
/*
|
|
* Count the columns used for characters
|
|
* since the start of input or after a
|
|
* previous tab.
|
|
* This info is used to go back the correct
|
|
* number of columns.
|
|
*/
|
|
while (tail != ldata->canon_head) {
|
|
tail--;
|
|
c = read_buf(ldata, tail);
|
|
if (c == '\t') {
|
|
after_tab = 1;
|
|
break;
|
|
} else if (iscntrl(c)) {
|
|
if (L_ECHOCTL(tty))
|
|
num_chars += 2;
|
|
} else if (!is_continuation(c, tty)) {
|
|
num_chars++;
|
|
}
|
|
}
|
|
echo_erase_tab(num_chars, after_tab, ldata);
|
|
} else {
|
|
if (iscntrl(c) && L_ECHOCTL(tty)) {
|
|
echo_char_raw('\b', ldata);
|
|
echo_char_raw(' ', ldata);
|
|
echo_char_raw('\b', ldata);
|
|
}
|
|
if (!iscntrl(c) || L_ECHOCTL(tty)) {
|
|
echo_char_raw('\b', ldata);
|
|
echo_char_raw(' ', ldata);
|
|
echo_char_raw('\b', ldata);
|
|
}
|
|
}
|
|
}
|
|
if (kill_type == ERASE)
|
|
break;
|
|
}
|
|
if (ldata->read_head == ldata->canon_head && L_ECHO(tty))
|
|
finish_erasing(ldata);
|
|
}
|
|
|
|
/**
|
|
* isig - handle the ISIG optio
|
|
* @sig: signal
|
|
* @tty: terminal
|
|
*
|
|
* Called when a signal is being sent due to terminal input.
|
|
* Called from the driver receive_buf path so serialized.
|
|
*
|
|
* Performs input and output flush if !NOFLSH. In this context, the echo
|
|
* buffer is 'output'. The signal is processed first to alert any current
|
|
* readers or writers to discontinue and exit their i/o loops.
|
|
*
|
|
* Locking: ctrl_lock
|
|
*/
|
|
|
|
static void __isig(int sig, struct tty_struct *tty)
|
|
{
|
|
struct pid *tty_pgrp = tty_get_pgrp(tty);
|
|
if (tty_pgrp) {
|
|
kill_pgrp(tty_pgrp, sig, 1);
|
|
put_pid(tty_pgrp);
|
|
}
|
|
}
|
|
|
|
static void isig(int sig, struct tty_struct *tty)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
|
|
if (L_NOFLSH(tty)) {
|
|
/* signal only */
|
|
__isig(sig, tty);
|
|
|
|
} else { /* signal and flush */
|
|
up_read(&tty->termios_rwsem);
|
|
down_write(&tty->termios_rwsem);
|
|
|
|
__isig(sig, tty);
|
|
|
|
/* clear echo buffer */
|
|
mutex_lock(&ldata->output_lock);
|
|
ldata->echo_head = ldata->echo_tail = 0;
|
|
ldata->echo_mark = ldata->echo_commit = 0;
|
|
mutex_unlock(&ldata->output_lock);
|
|
|
|
/* clear output buffer */
|
|
tty_driver_flush_buffer(tty);
|
|
|
|
/* clear input buffer */
|
|
reset_buffer_flags(tty->disc_data);
|
|
|
|
/* notify pty master of flush */
|
|
if (tty->link)
|
|
n_tty_packet_mode_flush(tty);
|
|
|
|
up_write(&tty->termios_rwsem);
|
|
down_read(&tty->termios_rwsem);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* 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.
|
|
*
|
|
* n_tty_receive_buf()/producer path:
|
|
* caller holds non-exclusive termios_rwsem
|
|
*
|
|
* Note: may get exclusive termios_rwsem if flushing input buffer
|
|
*/
|
|
|
|
static void n_tty_receive_break(struct tty_struct *tty)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
|
|
if (I_IGNBRK(tty))
|
|
return;
|
|
if (I_BRKINT(tty)) {
|
|
isig(SIGINT, tty);
|
|
return;
|
|
}
|
|
if (I_PARMRK(tty)) {
|
|
put_tty_queue('\377', ldata);
|
|
put_tty_queue('\0', ldata);
|
|
}
|
|
put_tty_queue('\0', ldata);
|
|
}
|
|
|
|
/**
|
|
* 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 void n_tty_receive_overrun(struct tty_struct *tty)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
|
|
ldata->num_overrun++;
|
|
if (time_after(jiffies, ldata->overrun_time + HZ) ||
|
|
time_after(ldata->overrun_time, jiffies)) {
|
|
tty_warn(tty, "%d input overrun(s)\n", ldata->num_overrun);
|
|
ldata->overrun_time = jiffies;
|
|
ldata->num_overrun = 0;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* n_tty_receive_parity_error - error notifier
|
|
* @tty: terminal device
|
|
* @c: character
|
|
*
|
|
* Process a parity error and queue the right data to indicate
|
|
* the error case if necessary.
|
|
*
|
|
* n_tty_receive_buf()/producer path:
|
|
* caller holds non-exclusive termios_rwsem
|
|
*/
|
|
static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
|
|
if (I_INPCK(tty)) {
|
|
if (I_IGNPAR(tty))
|
|
return;
|
|
if (I_PARMRK(tty)) {
|
|
put_tty_queue('\377', ldata);
|
|
put_tty_queue('\0', ldata);
|
|
put_tty_queue(c, ldata);
|
|
} else
|
|
put_tty_queue('\0', ldata);
|
|
} else
|
|
put_tty_queue(c, ldata);
|
|
}
|
|
|
|
static void
|
|
n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c)
|
|
{
|
|
isig(signal, tty);
|
|
if (I_IXON(tty))
|
|
start_tty(tty);
|
|
if (L_ECHO(tty)) {
|
|
echo_char(c, tty);
|
|
commit_echoes(tty);
|
|
} else
|
|
process_echoes(tty);
|
|
return;
|
|
}
|
|
|
|
/**
|
|
* 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.
|
|
*
|
|
* n_tty_receive_buf()/producer path:
|
|
* caller holds non-exclusive termios_rwsem
|
|
* publishes canon_head if canonical mode is active
|
|
*
|
|
* Returns 1 if LNEXT was received, else returns 0
|
|
*/
|
|
|
|
static int
|
|
n_tty_receive_char_special(struct tty_struct *tty, unsigned char c)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
|
|
if (I_IXON(tty)) {
|
|
if (c == START_CHAR(tty)) {
|
|
start_tty(tty);
|
|
process_echoes(tty);
|
|
return 0;
|
|
}
|
|
if (c == STOP_CHAR(tty)) {
|
|
stop_tty(tty);
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
if (L_ISIG(tty)) {
|
|
if (c == INTR_CHAR(tty)) {
|
|
n_tty_receive_signal_char(tty, SIGINT, c);
|
|
return 0;
|
|
} else if (c == QUIT_CHAR(tty)) {
|
|
n_tty_receive_signal_char(tty, SIGQUIT, c);
|
|
return 0;
|
|
} else if (c == SUSP_CHAR(tty)) {
|
|
n_tty_receive_signal_char(tty, SIGTSTP, c);
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) {
|
|
start_tty(tty);
|
|
process_echoes(tty);
|
|
}
|
|
|
|
if (c == '\r') {
|
|
if (I_IGNCR(tty))
|
|
return 0;
|
|
if (I_ICRNL(tty))
|
|
c = '\n';
|
|
} else if (c == '\n' && I_INLCR(tty))
|
|
c = '\r';
|
|
|
|
if (ldata->icanon) {
|
|
if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) ||
|
|
(c == WERASE_CHAR(tty) && L_IEXTEN(tty))) {
|
|
eraser(c, tty);
|
|
commit_echoes(tty);
|
|
return 0;
|
|
}
|
|
if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) {
|
|
ldata->lnext = 1;
|
|
if (L_ECHO(tty)) {
|
|
finish_erasing(ldata);
|
|
if (L_ECHOCTL(tty)) {
|
|
echo_char_raw('^', ldata);
|
|
echo_char_raw('\b', ldata);
|
|
commit_echoes(tty);
|
|
}
|
|
}
|
|
return 1;
|
|
}
|
|
if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && L_IEXTEN(tty)) {
|
|
size_t tail = ldata->canon_head;
|
|
|
|
finish_erasing(ldata);
|
|
echo_char(c, tty);
|
|
echo_char_raw('\n', ldata);
|
|
while (tail != ldata->read_head) {
|
|
echo_char(read_buf(ldata, tail), tty);
|
|
tail++;
|
|
}
|
|
commit_echoes(tty);
|
|
return 0;
|
|
}
|
|
if (c == '\n') {
|
|
if (L_ECHO(tty) || L_ECHONL(tty)) {
|
|
echo_char_raw('\n', ldata);
|
|
commit_echoes(tty);
|
|
}
|
|
goto handle_newline;
|
|
}
|
|
if (c == EOF_CHAR(tty)) {
|
|
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)) {
|
|
/* Record the column of first canon char. */
|
|
if (ldata->canon_head == ldata->read_head)
|
|
echo_set_canon_col(ldata);
|
|
echo_char(c, tty);
|
|
commit_echoes(tty);
|
|
}
|
|
/*
|
|
* XXX does PARMRK doubling happen for
|
|
* EOL_CHAR and EOL2_CHAR?
|
|
*/
|
|
if (c == (unsigned char) '\377' && I_PARMRK(tty))
|
|
put_tty_queue(c, ldata);
|
|
|
|
handle_newline:
|
|
set_bit(ldata->read_head & (N_TTY_BUF_SIZE - 1), ldata->read_flags);
|
|
put_tty_queue(c, ldata);
|
|
smp_store_release(&ldata->canon_head, ldata->read_head);
|
|
kill_fasync(&tty->fasync, SIGIO, POLL_IN);
|
|
wake_up_interruptible_poll(&tty->read_wait, POLLIN);
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
if (L_ECHO(tty)) {
|
|
finish_erasing(ldata);
|
|
if (c == '\n')
|
|
echo_char_raw('\n', ldata);
|
|
else {
|
|
/* Record the column of first canon char. */
|
|
if (ldata->canon_head == ldata->read_head)
|
|
echo_set_canon_col(ldata);
|
|
echo_char(c, tty);
|
|
}
|
|
commit_echoes(tty);
|
|
}
|
|
|
|
/* PARMRK doubling check */
|
|
if (c == (unsigned char) '\377' && I_PARMRK(tty))
|
|
put_tty_queue(c, ldata);
|
|
|
|
put_tty_queue(c, ldata);
|
|
return 0;
|
|
}
|
|
|
|
static inline void
|
|
n_tty_receive_char_inline(struct tty_struct *tty, unsigned char c)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
|
|
if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) {
|
|
start_tty(tty);
|
|
process_echoes(tty);
|
|
}
|
|
if (L_ECHO(tty)) {
|
|
finish_erasing(ldata);
|
|
/* Record the column of first canon char. */
|
|
if (ldata->canon_head == ldata->read_head)
|
|
echo_set_canon_col(ldata);
|
|
echo_char(c, tty);
|
|
commit_echoes(tty);
|
|
}
|
|
/* PARMRK doubling check */
|
|
if (c == (unsigned char) '\377' && I_PARMRK(tty))
|
|
put_tty_queue(c, ldata);
|
|
put_tty_queue(c, ldata);
|
|
}
|
|
|
|
static void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
|
|
{
|
|
n_tty_receive_char_inline(tty, c);
|
|
}
|
|
|
|
static inline void
|
|
n_tty_receive_char_fast(struct tty_struct *tty, unsigned char c)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
|
|
if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) {
|
|
start_tty(tty);
|
|
process_echoes(tty);
|
|
}
|
|
if (L_ECHO(tty)) {
|
|
finish_erasing(ldata);
|
|
/* Record the column of first canon char. */
|
|
if (ldata->canon_head == ldata->read_head)
|
|
echo_set_canon_col(ldata);
|
|
echo_char(c, tty);
|
|
commit_echoes(tty);
|
|
}
|
|
put_tty_queue(c, ldata);
|
|
}
|
|
|
|
static void n_tty_receive_char_closing(struct tty_struct *tty, unsigned char c)
|
|
{
|
|
if (I_ISTRIP(tty))
|
|
c &= 0x7f;
|
|
if (I_IUCLC(tty) && L_IEXTEN(tty))
|
|
c = tolower(c);
|
|
|
|
if (I_IXON(tty)) {
|
|
if (c == STOP_CHAR(tty))
|
|
stop_tty(tty);
|
|
else if (c == START_CHAR(tty) ||
|
|
(tty->stopped && !tty->flow_stopped && I_IXANY(tty) &&
|
|
c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) &&
|
|
c != SUSP_CHAR(tty))) {
|
|
start_tty(tty);
|
|
process_echoes(tty);
|
|
}
|
|
}
|
|
}
|
|
|
|
static void
|
|
n_tty_receive_char_flagged(struct tty_struct *tty, unsigned char c, char flag)
|
|
{
|
|
switch (flag) {
|
|
case TTY_BREAK:
|
|
n_tty_receive_break(tty);
|
|
break;
|
|
case TTY_PARITY:
|
|
case TTY_FRAME:
|
|
n_tty_receive_parity_error(tty, c);
|
|
break;
|
|
case TTY_OVERRUN:
|
|
n_tty_receive_overrun(tty);
|
|
break;
|
|
default:
|
|
tty_err(tty, "unknown flag %d\n", flag);
|
|
break;
|
|
}
|
|
}
|
|
|
|
static void
|
|
n_tty_receive_char_lnext(struct tty_struct *tty, unsigned char c, char flag)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
|
|
ldata->lnext = 0;
|
|
if (likely(flag == TTY_NORMAL)) {
|
|
if (I_ISTRIP(tty))
|
|
c &= 0x7f;
|
|
if (I_IUCLC(tty) && L_IEXTEN(tty))
|
|
c = tolower(c);
|
|
n_tty_receive_char(tty, c);
|
|
} else
|
|
n_tty_receive_char_flagged(tty, c, flag);
|
|
}
|
|
|
|
static void
|
|
n_tty_receive_buf_real_raw(struct tty_struct *tty, const unsigned char *cp,
|
|
char *fp, int count)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
size_t n, head;
|
|
|
|
head = ldata->read_head & (N_TTY_BUF_SIZE - 1);
|
|
n = min_t(size_t, count, N_TTY_BUF_SIZE - head);
|
|
memcpy(read_buf_addr(ldata, head), cp, n);
|
|
ldata->read_head += n;
|
|
cp += n;
|
|
count -= n;
|
|
|
|
head = ldata->read_head & (N_TTY_BUF_SIZE - 1);
|
|
n = min_t(size_t, count, N_TTY_BUF_SIZE - head);
|
|
memcpy(read_buf_addr(ldata, head), cp, n);
|
|
ldata->read_head += n;
|
|
}
|
|
|
|
static void
|
|
n_tty_receive_buf_raw(struct tty_struct *tty, const unsigned char *cp,
|
|
char *fp, int count)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
char flag = TTY_NORMAL;
|
|
|
|
while (count--) {
|
|
if (fp)
|
|
flag = *fp++;
|
|
if (likely(flag == TTY_NORMAL))
|
|
put_tty_queue(*cp++, ldata);
|
|
else
|
|
n_tty_receive_char_flagged(tty, *cp++, flag);
|
|
}
|
|
}
|
|
|
|
static void
|
|
n_tty_receive_buf_closing(struct tty_struct *tty, const unsigned char *cp,
|
|
char *fp, int count)
|
|
{
|
|
char flag = TTY_NORMAL;
|
|
|
|
while (count--) {
|
|
if (fp)
|
|
flag = *fp++;
|
|
if (likely(flag == TTY_NORMAL))
|
|
n_tty_receive_char_closing(tty, *cp++);
|
|
}
|
|
}
|
|
|
|
static void
|
|
n_tty_receive_buf_standard(struct tty_struct *tty, const unsigned char *cp,
|
|
char *fp, int count)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
char flag = TTY_NORMAL;
|
|
|
|
while (count--) {
|
|
if (fp)
|
|
flag = *fp++;
|
|
if (likely(flag == TTY_NORMAL)) {
|
|
unsigned char c = *cp++;
|
|
|
|
if (I_ISTRIP(tty))
|
|
c &= 0x7f;
|
|
if (I_IUCLC(tty) && L_IEXTEN(tty))
|
|
c = tolower(c);
|
|
if (L_EXTPROC(tty)) {
|
|
put_tty_queue(c, ldata);
|
|
continue;
|
|
}
|
|
if (!test_bit(c, ldata->char_map))
|
|
n_tty_receive_char_inline(tty, c);
|
|
else if (n_tty_receive_char_special(tty, c) && count) {
|
|
if (fp)
|
|
flag = *fp++;
|
|
n_tty_receive_char_lnext(tty, *cp++, flag);
|
|
count--;
|
|
}
|
|
} else
|
|
n_tty_receive_char_flagged(tty, *cp++, flag);
|
|
}
|
|
}
|
|
|
|
static void
|
|
n_tty_receive_buf_fast(struct tty_struct *tty, const unsigned char *cp,
|
|
char *fp, int count)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
char flag = TTY_NORMAL;
|
|
|
|
while (count--) {
|
|
if (fp)
|
|
flag = *fp++;
|
|
if (likely(flag == TTY_NORMAL)) {
|
|
unsigned char c = *cp++;
|
|
|
|
if (!test_bit(c, ldata->char_map))
|
|
n_tty_receive_char_fast(tty, c);
|
|
else if (n_tty_receive_char_special(tty, c) && count) {
|
|
if (fp)
|
|
flag = *fp++;
|
|
n_tty_receive_char_lnext(tty, *cp++, flag);
|
|
count--;
|
|
}
|
|
} else
|
|
n_tty_receive_char_flagged(tty, *cp++, flag);
|
|
}
|
|
}
|
|
|
|
static void __receive_buf(struct tty_struct *tty, const unsigned char *cp,
|
|
char *fp, int count)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
bool preops = I_ISTRIP(tty) || (I_IUCLC(tty) && L_IEXTEN(tty));
|
|
|
|
if (ldata->real_raw)
|
|
n_tty_receive_buf_real_raw(tty, cp, fp, count);
|
|
else if (ldata->raw || (L_EXTPROC(tty) && !preops))
|
|
n_tty_receive_buf_raw(tty, cp, fp, count);
|
|
else if (tty->closing && !L_EXTPROC(tty))
|
|
n_tty_receive_buf_closing(tty, cp, fp, count);
|
|
else {
|
|
if (ldata->lnext) {
|
|
char flag = TTY_NORMAL;
|
|
|
|
if (fp)
|
|
flag = *fp++;
|
|
n_tty_receive_char_lnext(tty, *cp++, flag);
|
|
count--;
|
|
}
|
|
|
|
if (!preops && !I_PARMRK(tty))
|
|
n_tty_receive_buf_fast(tty, cp, fp, count);
|
|
else
|
|
n_tty_receive_buf_standard(tty, cp, fp, count);
|
|
|
|
flush_echoes(tty);
|
|
if (tty->ops->flush_chars)
|
|
tty->ops->flush_chars(tty);
|
|
}
|
|
|
|
if (ldata->icanon && !L_EXTPROC(tty))
|
|
return;
|
|
|
|
/* publish read_head to consumer */
|
|
smp_store_release(&ldata->commit_head, ldata->read_head);
|
|
|
|
if (read_cnt(ldata)) {
|
|
kill_fasync(&tty->fasync, SIGIO, POLL_IN);
|
|
wake_up_interruptible_poll(&tty->read_wait, POLLIN);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* n_tty_receive_buf_common - process input
|
|
* @tty: device to receive input
|
|
* @cp: input chars
|
|
* @fp: flags for each char (if NULL, all chars are TTY_NORMAL)
|
|
* @count: number of input chars in @cp
|
|
*
|
|
* 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)
|
|
*
|
|
* Returns the # of input chars from @cp which were processed.
|
|
*
|
|
* In canonical mode, the maximum line length is 4096 chars (including
|
|
* the line termination char); lines longer than 4096 chars are
|
|
* truncated. After 4095 chars, input data is still processed but
|
|
* not stored. Overflow processing ensures the tty can always
|
|
* receive more input until at least one line can be read.
|
|
*
|
|
* In non-canonical mode, the read buffer will only accept 4095 chars;
|
|
* this provides the necessary space for a newline char if the input
|
|
* mode is switched to canonical.
|
|
*
|
|
* Note it is possible for the read buffer to _contain_ 4096 chars
|
|
* in non-canonical mode: the read buffer could already contain the
|
|
* maximum canon line of 4096 chars when the mode is switched to
|
|
* non-canonical.
|
|
*
|
|
* n_tty_receive_buf()/producer path:
|
|
* claims non-exclusive termios_rwsem
|
|
* publishes commit_head or canon_head
|
|
*/
|
|
static int
|
|
n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp,
|
|
char *fp, int count, int flow)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
int room, n, rcvd = 0, overflow;
|
|
|
|
down_read(&tty->termios_rwsem);
|
|
|
|
while (1) {
|
|
/*
|
|
* When PARMRK is set, each input char may take up to 3 chars
|
|
* in the read buf; reduce the buffer space avail by 3x
|
|
*
|
|
* 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.
|
|
*
|
|
* paired with store in *_copy_from_read_buf() -- guarantees
|
|
* the consumer has loaded the data in read_buf up to the new
|
|
* read_tail (so this producer will not overwrite unread data)
|
|
*/
|
|
size_t tail = smp_load_acquire(&ldata->read_tail);
|
|
|
|
room = N_TTY_BUF_SIZE - (ldata->read_head - tail);
|
|
if (I_PARMRK(tty))
|
|
room = (room + 2) / 3;
|
|
room--;
|
|
if (room <= 0) {
|
|
overflow = ldata->icanon && ldata->canon_head == tail;
|
|
if (overflow && room < 0)
|
|
ldata->read_head--;
|
|
room = overflow;
|
|
ldata->no_room = flow && !room;
|
|
} else
|
|
overflow = 0;
|
|
|
|
n = min(count, room);
|
|
if (!n)
|
|
break;
|
|
|
|
/* ignore parity errors if handling overflow */
|
|
if (!overflow || !fp || *fp != TTY_PARITY)
|
|
__receive_buf(tty, cp, fp, n);
|
|
|
|
cp += n;
|
|
if (fp)
|
|
fp += n;
|
|
count -= n;
|
|
rcvd += n;
|
|
}
|
|
|
|
tty->receive_room = room;
|
|
|
|
/* Unthrottle if handling overflow on pty */
|
|
if (tty->driver->type == TTY_DRIVER_TYPE_PTY) {
|
|
if (overflow) {
|
|
tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE);
|
|
tty_unthrottle_safe(tty);
|
|
__tty_set_flow_change(tty, 0);
|
|
}
|
|
} else
|
|
n_tty_check_throttle(tty);
|
|
|
|
up_read(&tty->termios_rwsem);
|
|
|
|
return rcvd;
|
|
}
|
|
|
|
static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
|
|
char *fp, int count)
|
|
{
|
|
n_tty_receive_buf_common(tty, cp, fp, count, 0);
|
|
}
|
|
|
|
static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp,
|
|
char *fp, int count)
|
|
{
|
|
return n_tty_receive_buf_common(tty, cp, fp, count, 1);
|
|
}
|
|
|
|
/**
|
|
* n_tty_set_termios - termios data changed
|
|
* @tty: terminal
|
|
* @old: previous data
|
|
*
|
|
* Called by the tty layer when the user changes termios flags so
|
|
* that the line discipline can plan ahead. This function cannot sleep
|
|
* and is protected from re-entry by the tty layer. The user is
|
|
* guaranteed that this function will not be re-entered or in progress
|
|
* when the ldisc is closed.
|
|
*
|
|
* Locking: Caller holds tty->termios_rwsem
|
|
*/
|
|
|
|
static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
|
|
if (!old || (old->c_lflag ^ tty->termios.c_lflag) & ICANON) {
|
|
bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE);
|
|
ldata->line_start = ldata->read_tail;
|
|
if (!L_ICANON(tty) || !read_cnt(ldata)) {
|
|
ldata->canon_head = ldata->read_tail;
|
|
ldata->push = 0;
|
|
} else {
|
|
set_bit((ldata->read_head - 1) & (N_TTY_BUF_SIZE - 1),
|
|
ldata->read_flags);
|
|
ldata->canon_head = ldata->read_head;
|
|
ldata->push = 1;
|
|
}
|
|
ldata->commit_head = ldata->read_head;
|
|
ldata->erasing = 0;
|
|
ldata->lnext = 0;
|
|
}
|
|
|
|
ldata->icanon = (L_ICANON(tty) != 0);
|
|
|
|
if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) ||
|
|
I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) ||
|
|
I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) ||
|
|
I_PARMRK(tty)) {
|
|
bitmap_zero(ldata->char_map, 256);
|
|
|
|
if (I_IGNCR(tty) || I_ICRNL(tty))
|
|
set_bit('\r', ldata->char_map);
|
|
if (I_INLCR(tty))
|
|
set_bit('\n', ldata->char_map);
|
|
|
|
if (L_ICANON(tty)) {
|
|
set_bit(ERASE_CHAR(tty), ldata->char_map);
|
|
set_bit(KILL_CHAR(tty), ldata->char_map);
|
|
set_bit(EOF_CHAR(tty), ldata->char_map);
|
|
set_bit('\n', ldata->char_map);
|
|
set_bit(EOL_CHAR(tty), ldata->char_map);
|
|
if (L_IEXTEN(tty)) {
|
|
set_bit(WERASE_CHAR(tty), ldata->char_map);
|
|
set_bit(LNEXT_CHAR(tty), ldata->char_map);
|
|
set_bit(EOL2_CHAR(tty), ldata->char_map);
|
|
if (L_ECHO(tty))
|
|
set_bit(REPRINT_CHAR(tty),
|
|
ldata->char_map);
|
|
}
|
|
}
|
|
if (I_IXON(tty)) {
|
|
set_bit(START_CHAR(tty), ldata->char_map);
|
|
set_bit(STOP_CHAR(tty), ldata->char_map);
|
|
}
|
|
if (L_ISIG(tty)) {
|
|
set_bit(INTR_CHAR(tty), ldata->char_map);
|
|
set_bit(QUIT_CHAR(tty), ldata->char_map);
|
|
set_bit(SUSP_CHAR(tty), ldata->char_map);
|
|
}
|
|
clear_bit(__DISABLED_CHAR, ldata->char_map);
|
|
ldata->raw = 0;
|
|
ldata->real_raw = 0;
|
|
} else {
|
|
ldata->raw = 1;
|
|
if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) &&
|
|
(I_IGNPAR(tty) || !I_INPCK(tty)) &&
|
|
(tty->driver->flags & TTY_DRIVER_REAL_RAW))
|
|
ldata->real_raw = 1;
|
|
else
|
|
ldata->real_raw = 0;
|
|
}
|
|
/*
|
|
* Fix tty hang when I_IXON(tty) is cleared, but the tty
|
|
* been stopped by STOP_CHAR(tty) before it.
|
|
*/
|
|
if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) {
|
|
start_tty(tty);
|
|
process_echoes(tty);
|
|
}
|
|
|
|
/* The termios change make the tty ready for I/O */
|
|
wake_up_interruptible(&tty->write_wait);
|
|
wake_up_interruptible(&tty->read_wait);
|
|
}
|
|
|
|
/**
|
|
* n_tty_close - close the ldisc for this tty
|
|
* @tty: device
|
|
*
|
|
* Called from the terminal layer when this line discipline is
|
|
* being shut down, either because of a close or becsuse of a
|
|
* discipline change. The function will not be called while other
|
|
* ldisc methods are in progress.
|
|
*/
|
|
|
|
static void n_tty_close(struct tty_struct *tty)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
|
|
if (tty->link)
|
|
n_tty_packet_mode_flush(tty);
|
|
|
|
vfree(ldata);
|
|
tty->disc_data = NULL;
|
|
}
|
|
|
|
/**
|
|
* n_tty_open - open an ldisc
|
|
* @tty: terminal to open
|
|
*
|
|
* Called when this line discipline is being attached to the
|
|
* terminal device. Can sleep. Called serialized so that no
|
|
* other events will occur in parallel. No further open will occur
|
|
* until a close.
|
|
*/
|
|
|
|
static int n_tty_open(struct tty_struct *tty)
|
|
{
|
|
struct n_tty_data *ldata;
|
|
|
|
/* Currently a malloc failure here can panic */
|
|
ldata = vmalloc(sizeof(*ldata));
|
|
if (!ldata)
|
|
goto err;
|
|
|
|
ldata->overrun_time = jiffies;
|
|
mutex_init(&ldata->atomic_read_lock);
|
|
mutex_init(&ldata->output_lock);
|
|
|
|
tty->disc_data = ldata;
|
|
reset_buffer_flags(tty->disc_data);
|
|
ldata->column = 0;
|
|
ldata->canon_column = 0;
|
|
ldata->num_overrun = 0;
|
|
ldata->no_room = 0;
|
|
ldata->lnext = 0;
|
|
tty->closing = 0;
|
|
/* indicate buffer work may resume */
|
|
clear_bit(TTY_LDISC_HALTED, &tty->flags);
|
|
n_tty_set_termios(tty, NULL);
|
|
tty_unthrottle(tty);
|
|
|
|
return 0;
|
|
err:
|
|
return -ENOMEM;
|
|
}
|
|
|
|
static inline int input_available_p(struct tty_struct *tty, int poll)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
int amt = poll && !TIME_CHAR(tty) && MIN_CHAR(tty) ? MIN_CHAR(tty) : 1;
|
|
|
|
if (ldata->icanon && !L_EXTPROC(tty))
|
|
return ldata->canon_head != ldata->read_tail;
|
|
else
|
|
return ldata->commit_head - ldata->read_tail >= amt;
|
|
}
|
|
|
|
/**
|
|
* copy_from_read_buf - copy read data directly
|
|
* @tty: terminal device
|
|
* @b: user data
|
|
* @nr: size of data
|
|
*
|
|
* Helper function to speed up n_tty_read. It is only called when
|
|
* ICANON is off; it copies characters straight from the tty queue to
|
|
* user space directly. It can be profitably called twice; once to
|
|
* drain the space from the tail pointer to the (physical) end of the
|
|
* buffer, and once to drain the space from the (physical) beginning of
|
|
* the buffer to head pointer.
|
|
*
|
|
* Called under the ldata->atomic_read_lock sem
|
|
*
|
|
* n_tty_read()/consumer path:
|
|
* caller holds non-exclusive termios_rwsem
|
|
* read_tail published
|
|
*/
|
|
|
|
static int copy_from_read_buf(struct tty_struct *tty,
|
|
unsigned char __user **b,
|
|
size_t *nr)
|
|
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
int retval;
|
|
size_t n;
|
|
bool is_eof;
|
|
size_t head = smp_load_acquire(&ldata->commit_head);
|
|
size_t tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1);
|
|
|
|
retval = 0;
|
|
n = min(head - ldata->read_tail, N_TTY_BUF_SIZE - tail);
|
|
n = min(*nr, n);
|
|
if (n) {
|
|
const unsigned char *from = read_buf_addr(ldata, tail);
|
|
retval = copy_to_user(*b, from, n);
|
|
n -= retval;
|
|
is_eof = n == 1 && *from == EOF_CHAR(tty);
|
|
tty_audit_add_data(tty, from, n);
|
|
smp_store_release(&ldata->read_tail, ldata->read_tail + n);
|
|
/* Turn single EOF into zero-length read */
|
|
if (L_EXTPROC(tty) && ldata->icanon && is_eof &&
|
|
(head == ldata->read_tail))
|
|
n = 0;
|
|
*b += n;
|
|
*nr -= n;
|
|
}
|
|
return retval;
|
|
}
|
|
|
|
/**
|
|
* canon_copy_from_read_buf - copy read data in canonical mode
|
|
* @tty: terminal device
|
|
* @b: user data
|
|
* @nr: size of data
|
|
*
|
|
* Helper function for n_tty_read. It is only called when ICANON is on;
|
|
* it copies one line of input up to and including the line-delimiting
|
|
* character into the user-space buffer.
|
|
*
|
|
* NB: When termios is changed from non-canonical to canonical mode and
|
|
* the read buffer contains data, n_tty_set_termios() simulates an EOF
|
|
* push (as if C-d were input) _without_ the DISABLED_CHAR in the buffer.
|
|
* This causes data already processed as input to be immediately available
|
|
* as input although a newline has not been received.
|
|
*
|
|
* Called under the atomic_read_lock mutex
|
|
*
|
|
* n_tty_read()/consumer path:
|
|
* caller holds non-exclusive termios_rwsem
|
|
* read_tail published
|
|
*/
|
|
|
|
static int canon_copy_from_read_buf(struct tty_struct *tty,
|
|
unsigned char __user **b,
|
|
size_t *nr)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
size_t n, size, more, c;
|
|
size_t eol;
|
|
size_t tail;
|
|
int ret, found = 0;
|
|
|
|
/* N.B. avoid overrun if nr == 0 */
|
|
if (!*nr)
|
|
return 0;
|
|
|
|
n = min(*nr + 1, smp_load_acquire(&ldata->canon_head) - ldata->read_tail);
|
|
|
|
tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1);
|
|
size = min_t(size_t, tail + n, N_TTY_BUF_SIZE);
|
|
|
|
n_tty_trace("%s: nr:%zu tail:%zu n:%zu size:%zu\n",
|
|
__func__, *nr, tail, n, size);
|
|
|
|
eol = find_next_bit(ldata->read_flags, size, tail);
|
|
more = n - (size - tail);
|
|
if (eol == N_TTY_BUF_SIZE && more) {
|
|
/* scan wrapped without finding set bit */
|
|
eol = find_next_bit(ldata->read_flags, more, 0);
|
|
found = eol != more;
|
|
} else
|
|
found = eol != size;
|
|
|
|
n = eol - tail;
|
|
if (n > N_TTY_BUF_SIZE)
|
|
n += N_TTY_BUF_SIZE;
|
|
c = n + found;
|
|
|
|
if (!found || read_buf(ldata, eol) != __DISABLED_CHAR) {
|
|
c = min(*nr, c);
|
|
n = c;
|
|
}
|
|
|
|
n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu tail:%zu more:%zu\n",
|
|
__func__, eol, found, n, c, tail, more);
|
|
|
|
ret = tty_copy_to_user(tty, *b, tail, n);
|
|
if (ret)
|
|
return -EFAULT;
|
|
*b += n;
|
|
*nr -= n;
|
|
|
|
if (found)
|
|
clear_bit(eol, ldata->read_flags);
|
|
smp_store_release(&ldata->read_tail, ldata->read_tail + c);
|
|
|
|
if (found) {
|
|
if (!ldata->push)
|
|
ldata->line_start = ldata->read_tail;
|
|
else
|
|
ldata->push = 0;
|
|
tty_audit_push();
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
extern ssize_t redirected_tty_write(struct file *, const char __user *,
|
|
size_t, loff_t *);
|
|
|
|
/**
|
|
* job_control - check job control
|
|
* @tty: tty
|
|
* @file: file handle
|
|
*
|
|
* Perform job control management checks on this file/tty descriptor
|
|
* and if appropriate send any needed signals and return a negative
|
|
* error code if action should be taken.
|
|
*
|
|
* Locking: redirected write test is safe
|
|
* current->signal->tty check is safe
|
|
* ctrl_lock to safely reference tty->pgrp
|
|
*/
|
|
|
|
static int job_control(struct tty_struct *tty, struct file *file)
|
|
{
|
|
/* 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)
|
|
return 0;
|
|
|
|
return __tty_check_change(tty, SIGTTIN);
|
|
}
|
|
|
|
|
|
/**
|
|
* n_tty_read - read function for tty
|
|
* @tty: tty device
|
|
* @file: file object
|
|
* @buf: userspace buffer pointer
|
|
* @nr: size of I/O
|
|
*
|
|
* Perform reads for the line discipline. We are guaranteed that the
|
|
* line discipline will not be closed under us but we may get multiple
|
|
* parallel readers and must handle this ourselves. We may also get
|
|
* a hangup. Always called in user context, may sleep.
|
|
*
|
|
* This code must be sure never to sleep through a hangup.
|
|
*
|
|
* n_tty_read()/consumer path:
|
|
* claims non-exclusive termios_rwsem
|
|
* publishes read_tail
|
|
*/
|
|
|
|
static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
|
|
unsigned char __user *buf, size_t nr)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
unsigned char __user *b = buf;
|
|
DEFINE_WAIT_FUNC(wait, woken_wake_function);
|
|
int c;
|
|
int minimum, time;
|
|
ssize_t retval = 0;
|
|
long timeout;
|
|
int packet;
|
|
size_t tail;
|
|
|
|
c = job_control(tty, file);
|
|
if (c < 0)
|
|
return c;
|
|
|
|
/*
|
|
* Internal serialization of reads.
|
|
*/
|
|
if (file->f_flags & O_NONBLOCK) {
|
|
if (!mutex_trylock(&ldata->atomic_read_lock))
|
|
return -EAGAIN;
|
|
} else {
|
|
if (mutex_lock_interruptible(&ldata->atomic_read_lock))
|
|
return -ERESTARTSYS;
|
|
}
|
|
|
|
down_read(&tty->termios_rwsem);
|
|
|
|
minimum = time = 0;
|
|
timeout = MAX_SCHEDULE_TIMEOUT;
|
|
if (!ldata->icanon) {
|
|
minimum = MIN_CHAR(tty);
|
|
if (minimum) {
|
|
time = (HZ / 10) * TIME_CHAR(tty);
|
|
} else {
|
|
timeout = (HZ / 10) * TIME_CHAR(tty);
|
|
minimum = 1;
|
|
}
|
|
}
|
|
|
|
packet = tty->packet;
|
|
tail = ldata->read_tail;
|
|
|
|
add_wait_queue(&tty->read_wait, &wait);
|
|
while (nr) {
|
|
/* First test for status change. */
|
|
if (packet && tty->link->ctrl_status) {
|
|
unsigned char cs;
|
|
if (b != buf)
|
|
break;
|
|
spin_lock_irq(&tty->link->ctrl_lock);
|
|
cs = tty->link->ctrl_status;
|
|
tty->link->ctrl_status = 0;
|
|
spin_unlock_irq(&tty->link->ctrl_lock);
|
|
if (put_user(cs, b)) {
|
|
retval = -EFAULT;
|
|
break;
|
|
}
|
|
b++;
|
|
nr--;
|
|
break;
|
|
}
|
|
|
|
if (!input_available_p(tty, 0)) {
|
|
up_read(&tty->termios_rwsem);
|
|
tty_buffer_flush_work(tty->port);
|
|
down_read(&tty->termios_rwsem);
|
|
if (!input_available_p(tty, 0)) {
|
|
if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) {
|
|
retval = -EIO;
|
|
break;
|
|
}
|
|
if (tty_hung_up_p(file))
|
|
break;
|
|
if (!timeout)
|
|
break;
|
|
if (file->f_flags & O_NONBLOCK) {
|
|
retval = -EAGAIN;
|
|
break;
|
|
}
|
|
if (signal_pending(current)) {
|
|
retval = -ERESTARTSYS;
|
|
break;
|
|
}
|
|
up_read(&tty->termios_rwsem);
|
|
|
|
timeout = wait_woken(&wait, TASK_INTERRUPTIBLE,
|
|
timeout);
|
|
|
|
down_read(&tty->termios_rwsem);
|
|
continue;
|
|
}
|
|
}
|
|
|
|
if (ldata->icanon && !L_EXTPROC(tty)) {
|
|
retval = canon_copy_from_read_buf(tty, &b, &nr);
|
|
if (retval)
|
|
break;
|
|
} else {
|
|
int uncopied;
|
|
|
|
/* Deal with packet mode. */
|
|
if (packet && b == buf) {
|
|
if (put_user(TIOCPKT_DATA, b)) {
|
|
retval = -EFAULT;
|
|
break;
|
|
}
|
|
b++;
|
|
nr--;
|
|
}
|
|
|
|
uncopied = copy_from_read_buf(tty, &b, &nr);
|
|
uncopied += copy_from_read_buf(tty, &b, &nr);
|
|
if (uncopied) {
|
|
retval = -EFAULT;
|
|
break;
|
|
}
|
|
}
|
|
|
|
n_tty_check_unthrottle(tty);
|
|
|
|
if (b - buf >= minimum)
|
|
break;
|
|
if (time)
|
|
timeout = time;
|
|
}
|
|
if (tail != ldata->read_tail)
|
|
n_tty_kick_worker(tty);
|
|
up_read(&tty->termios_rwsem);
|
|
|
|
remove_wait_queue(&tty->read_wait, &wait);
|
|
mutex_unlock(&ldata->atomic_read_lock);
|
|
|
|
if (b - buf)
|
|
retval = b - buf;
|
|
|
|
return retval;
|
|
}
|
|
|
|
/**
|
|
* n_tty_write - write function for tty
|
|
* @tty: tty device
|
|
* @file: file object
|
|
* @buf: userspace buffer pointer
|
|
* @nr: size of I/O
|
|
*
|
|
* Write function of the terminal device. This is serialized with
|
|
* respect to other write callers but not to termios changes, reads
|
|
* and other such events. Since the receive code will echo characters,
|
|
* thus calling driver write methods, the output_lock is used in
|
|
* the output processing functions called here as well as in the
|
|
* echo processing function to protect the column state and space
|
|
* left in the buffer.
|
|
*
|
|
* This code must be sure never to sleep through a hangup.
|
|
*
|
|
* Locking: output_lock to protect column state and space left
|
|
* (note that the process_output*() functions take this
|
|
* lock themselves)
|
|
*/
|
|
|
|
static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
|
|
const unsigned char *buf, size_t nr)
|
|
{
|
|
const unsigned char *b = buf;
|
|
DEFINE_WAIT_FUNC(wait, woken_wake_function);
|
|
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;
|
|
}
|
|
|
|
down_read(&tty->termios_rwsem);
|
|
|
|
/* Write out any echoed characters that are still pending */
|
|
process_echoes(tty);
|
|
|
|
add_wait_queue(&tty->write_wait, &wait);
|
|
while (1) {
|
|
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)) {
|
|
while (nr > 0) {
|
|
ssize_t num = process_output_block(tty, b, nr);
|
|
if (num < 0) {
|
|
if (num == -EAGAIN)
|
|
break;
|
|
retval = num;
|
|
goto break_out;
|
|
}
|
|
b += num;
|
|
nr -= num;
|
|
if (nr == 0)
|
|
break;
|
|
c = *b;
|
|
if (process_output(c, tty) < 0)
|
|
break;
|
|
b++; nr--;
|
|
}
|
|
if (tty->ops->flush_chars)
|
|
tty->ops->flush_chars(tty);
|
|
} else {
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
|
|
while (nr > 0) {
|
|
mutex_lock(&ldata->output_lock);
|
|
c = tty->ops->write(tty, b, nr);
|
|
mutex_unlock(&ldata->output_lock);
|
|
if (c < 0) {
|
|
retval = c;
|
|
goto break_out;
|
|
}
|
|
if (!c)
|
|
break;
|
|
b += c;
|
|
nr -= c;
|
|
}
|
|
}
|
|
if (!nr)
|
|
break;
|
|
if (file->f_flags & O_NONBLOCK) {
|
|
retval = -EAGAIN;
|
|
break;
|
|
}
|
|
up_read(&tty->termios_rwsem);
|
|
|
|
wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
|
|
|
|
down_read(&tty->termios_rwsem);
|
|
}
|
|
break_out:
|
|
remove_wait_queue(&tty->write_wait, &wait);
|
|
if (nr && tty->fasync)
|
|
set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
|
|
up_read(&tty->termios_rwsem);
|
|
return (b - buf) ? b - buf : retval;
|
|
}
|
|
|
|
/**
|
|
* n_tty_poll - poll method for N_TTY
|
|
* @tty: terminal device
|
|
* @file: file accessing it
|
|
* @wait: poll table
|
|
*
|
|
* Called when the line discipline is asked to poll() for data or
|
|
* for special events. This code is not serialized with respect to
|
|
* other events save open/close.
|
|
*
|
|
* This code must be sure never to sleep through a hangup.
|
|
* Called without the kernel lock held - fine
|
|
*/
|
|
|
|
static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file,
|
|
poll_table *wait)
|
|
{
|
|
unsigned int mask = 0;
|
|
|
|
poll_wait(file, &tty->read_wait, wait);
|
|
poll_wait(file, &tty->write_wait, wait);
|
|
if (input_available_p(tty, 1))
|
|
mask |= POLLIN | POLLRDNORM;
|
|
else {
|
|
tty_buffer_flush_work(tty->port);
|
|
if (input_available_p(tty, 1))
|
|
mask |= POLLIN | POLLRDNORM;
|
|
}
|
|
if (tty->packet && tty->link->ctrl_status)
|
|
mask |= POLLPRI | POLLIN | POLLRDNORM;
|
|
if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
|
|
mask |= POLLHUP;
|
|
if (tty_hung_up_p(file))
|
|
mask |= POLLHUP;
|
|
if (tty->ops->write && !tty_is_writelocked(tty) &&
|
|
tty_chars_in_buffer(tty) < WAKEUP_CHARS &&
|
|
tty_write_room(tty) > 0)
|
|
mask |= POLLOUT | POLLWRNORM;
|
|
return mask;
|
|
}
|
|
|
|
static unsigned long inq_canon(struct n_tty_data *ldata)
|
|
{
|
|
size_t nr, head, tail;
|
|
|
|
if (ldata->canon_head == ldata->read_tail)
|
|
return 0;
|
|
head = ldata->canon_head;
|
|
tail = ldata->read_tail;
|
|
nr = head - tail;
|
|
/* Skip EOF-chars.. */
|
|
while (head != tail) {
|
|
if (test_bit(tail & (N_TTY_BUF_SIZE - 1), ldata->read_flags) &&
|
|
read_buf(ldata, tail) == __DISABLED_CHAR)
|
|
nr--;
|
|
tail++;
|
|
}
|
|
return nr;
|
|
}
|
|
|
|
static int n_tty_ioctl(struct tty_struct *tty, struct file *file,
|
|
unsigned int cmd, unsigned long arg)
|
|
{
|
|
struct n_tty_data *ldata = tty->disc_data;
|
|
int retval;
|
|
|
|
switch (cmd) {
|
|
case TIOCOUTQ:
|
|
return put_user(tty_chars_in_buffer(tty), (int __user *) arg);
|
|
case TIOCINQ:
|
|
down_write(&tty->termios_rwsem);
|
|
if (L_ICANON(tty))
|
|
retval = inq_canon(ldata);
|
|
else
|
|
retval = read_cnt(ldata);
|
|
up_write(&tty->termios_rwsem);
|
|
return put_user(retval, (unsigned int __user *) arg);
|
|
default:
|
|
return n_tty_ioctl_helper(tty, file, cmd, arg);
|
|
}
|
|
}
|
|
|
|
static struct tty_ldisc_ops n_tty_ops = {
|
|
.magic = TTY_LDISC_MAGIC,
|
|
.name = "n_tty",
|
|
.open = n_tty_open,
|
|
.close = n_tty_close,
|
|
.flush_buffer = n_tty_flush_buffer,
|
|
.read = n_tty_read,
|
|
.write = n_tty_write,
|
|
.ioctl = n_tty_ioctl,
|
|
.set_termios = n_tty_set_termios,
|
|
.poll = n_tty_poll,
|
|
.receive_buf = n_tty_receive_buf,
|
|
.write_wakeup = n_tty_write_wakeup,
|
|
.receive_buf2 = n_tty_receive_buf2,
|
|
};
|
|
|
|
/**
|
|
* n_tty_inherit_ops - inherit N_TTY methods
|
|
* @ops: struct tty_ldisc_ops where to save N_TTY methods
|
|
*
|
|
* Enables a 'subclass' line discipline to 'inherit' N_TTY methods.
|
|
*/
|
|
|
|
void n_tty_inherit_ops(struct tty_ldisc_ops *ops)
|
|
{
|
|
*ops = n_tty_ops;
|
|
ops->owner = NULL;
|
|
ops->refcount = ops->flags = 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(n_tty_inherit_ops);
|
|
|
|
void __init n_tty_init(void)
|
|
{
|
|
tty_register_ldisc(N_TTY, &n_tty_ops);
|
|
}
|