2 * linux/drivers/char/tty_io.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
8 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
9 * or rs-channels. It also implements echoing, cooked mode etc.
11 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
13 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
14 * tty_struct and tty_queue structures. Previously there was an array
15 * of 256 tty_struct's which was statically allocated, and the
16 * tty_queue structures were allocated at boot time. Both are now
17 * dynamically allocated only when the tty is open.
19 * Also restructured routines so that there is more of a separation
20 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
21 * the low-level tty routines (serial.c, pty.c, console.c). This
22 * makes for cleaner and more compact code. -TYT, 9/17/92
24 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
25 * which can be dynamically activated and de-activated by the line
26 * discipline handling modules (like SLIP).
28 * NOTE: pay no attention to the line discipline code (yet); its
29 * interface is still subject to change in this version...
32 * Added functionality to the OPOST tty handling. No delays, but all
33 * other bits should be there.
34 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
36 * Rewrote canonical mode and added more termios flags.
37 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
39 * Reorganized FASYNC support so mouse code can share it.
40 * -- ctm@ardi.com, 9Sep95
42 * New TIOCLINUX variants added.
43 * -- mj@k332.feld.cvut.cz, 19-Nov-95
45 * Restrict vt switching via ioctl()
46 * -- grif@cs.ucr.edu, 5-Dec-95
48 * Move console and virtual terminal code to more appropriate files,
49 * implement CONFIG_VT and generalize console device interface.
50 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
52 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
53 * -- Bill Hawes <whawes@star.net>, June 97
55 * Added devfs support.
56 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
58 * Added support for a Unix98-style ptmx device.
59 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
61 * Reduced memory usage for older ARM systems
62 * -- Russell King <rmk@arm.linux.org.uk>
64 * Move do_SAK() into process context. Less stack use in devfs functions.
65 * alloc_tty_struct() always uses kmalloc()
66 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
69 #include <linux/types.h>
70 #include <linux/major.h>
71 #include <linux/errno.h>
72 #include <linux/signal.h>
73 #include <linux/fcntl.h>
74 #include <linux/sched.h>
75 #include <linux/interrupt.h>
76 #include <linux/tty.h>
77 #include <linux/tty_driver.h>
78 #include <linux/tty_flip.h>
79 #include <linux/devpts_fs.h>
80 #include <linux/file.h>
81 #include <linux/fdtable.h>
82 #include <linux/console.h>
83 #include <linux/timer.h>
84 #include <linux/ctype.h>
87 #include <linux/string.h>
88 #include <linux/slab.h>
89 #include <linux/poll.h>
90 #include <linux/proc_fs.h>
91 #include <linux/init.h>
92 #include <linux/module.h>
93 #include <linux/smp_lock.h>
94 #include <linux/device.h>
95 #include <linux/wait.h>
96 #include <linux/bitops.h>
97 #include <linux/delay.h>
98 #include <linux/seq_file.h>
100 #include <linux/uaccess.h>
101 #include <asm/system.h>
103 #include <linux/kbd_kern.h>
104 #include <linux/vt_kern.h>
105 #include <linux/selection.h>
107 #include <linux/kmod.h>
108 #include <linux/nsproxy.h>
110 #undef TTY_DEBUG_HANGUP
112 #define TTY_PARANOIA_CHECK 1
113 #define CHECK_TTY_COUNT 1
115 struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
116 .c_iflag = ICRNL | IXON,
117 .c_oflag = OPOST | ONLCR,
118 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
119 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
120 ECHOCTL | ECHOKE | IEXTEN,
126 EXPORT_SYMBOL(tty_std_termios);
128 /* This list gets poked at by procfs and various bits of boot up code. This
129 could do with some rationalisation such as pulling the tty proc function
132 LIST_HEAD(tty_drivers); /* linked list of tty drivers */
134 /* Mutex to protect creating and releasing a tty. This is shared with
135 vt.c for deeply disgusting hack reasons */
136 DEFINE_MUTEX(tty_mutex);
137 EXPORT_SYMBOL(tty_mutex);
139 static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
140 static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
141 ssize_t redirected_tty_write(struct file *, const char __user *,
143 static unsigned int tty_poll(struct file *, poll_table *);
144 static int tty_open(struct inode *, struct file *);
145 static int tty_release(struct inode *, struct file *);
146 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
148 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
151 #define tty_compat_ioctl NULL
153 static int tty_fasync(int fd, struct file *filp, int on);
154 static void release_tty(struct tty_struct *tty, int idx);
155 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
156 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
159 * alloc_tty_struct - allocate a tty object
161 * Return a new empty tty structure. The data fields have not
162 * been initialized in any way but has been zeroed
167 struct tty_struct *alloc_tty_struct(void)
169 return kzalloc(sizeof(struct tty_struct), GFP_KERNEL);
173 * free_tty_struct - free a disused tty
174 * @tty: tty struct to free
176 * Free the write buffers, tty queue and tty memory itself.
178 * Locking: none. Must be called after tty is definitely unused
181 void free_tty_struct(struct tty_struct *tty)
183 kfree(tty->write_buf);
184 tty_buffer_free_all(tty);
188 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
191 * tty_name - return tty naming
192 * @tty: tty structure
193 * @buf: buffer for output
195 * Convert a tty structure into a name. The name reflects the kernel
196 * naming policy and if udev is in use may not reflect user space
201 char *tty_name(struct tty_struct *tty, char *buf)
203 if (!tty) /* Hmm. NULL pointer. That's fun. */
204 strcpy(buf, "NULL tty");
206 strcpy(buf, tty->name);
210 EXPORT_SYMBOL(tty_name);
212 int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
215 #ifdef TTY_PARANOIA_CHECK
218 "null TTY for (%d:%d) in %s\n",
219 imajor(inode), iminor(inode), routine);
222 if (tty->magic != TTY_MAGIC) {
224 "bad magic number for tty struct (%d:%d) in %s\n",
225 imajor(inode), iminor(inode), routine);
232 static int check_tty_count(struct tty_struct *tty, const char *routine)
234 #ifdef CHECK_TTY_COUNT
239 list_for_each(p, &tty->tty_files) {
243 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
244 tty->driver->subtype == PTY_TYPE_SLAVE &&
245 tty->link && tty->link->count)
247 if (tty->count != count) {
248 printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) "
249 "!= #fd's(%d) in %s\n",
250 tty->name, tty->count, count, routine);
258 * get_tty_driver - find device of a tty
259 * @dev_t: device identifier
260 * @index: returns the index of the tty
262 * This routine returns a tty driver structure, given a device number
263 * and also passes back the index number.
265 * Locking: caller must hold tty_mutex
268 static struct tty_driver *get_tty_driver(dev_t device, int *index)
270 struct tty_driver *p;
272 list_for_each_entry(p, &tty_drivers, tty_drivers) {
273 dev_t base = MKDEV(p->major, p->minor_start);
274 if (device < base || device >= base + p->num)
276 *index = device - base;
277 return tty_driver_kref_get(p);
282 #ifdef CONFIG_CONSOLE_POLL
285 * tty_find_polling_driver - find device of a polled tty
286 * @name: name string to match
287 * @line: pointer to resulting tty line nr
289 * This routine returns a tty driver structure, given a name
290 * and the condition that the tty driver is capable of polled
293 struct tty_driver *tty_find_polling_driver(char *name, int *line)
295 struct tty_driver *p, *res = NULL;
300 for (str = name; *str; str++)
301 if ((*str >= '0' && *str <= '9') || *str == ',')
307 tty_line = simple_strtoul(str, &str, 10);
309 mutex_lock(&tty_mutex);
310 /* Search through the tty devices to look for a match */
311 list_for_each_entry(p, &tty_drivers, tty_drivers) {
312 if (strncmp(name, p->name, len) != 0)
320 if (tty_line >= 0 && tty_line <= p->num && p->ops &&
321 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
322 res = tty_driver_kref_get(p);
327 mutex_unlock(&tty_mutex);
331 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
335 * tty_check_change - check for POSIX terminal changes
338 * If we try to write to, or set the state of, a terminal and we're
339 * not in the foreground, send a SIGTTOU. If the signal is blocked or
340 * ignored, go ahead and perform the operation. (POSIX 7.2)
345 int tty_check_change(struct tty_struct *tty)
350 if (current->signal->tty != tty)
353 spin_lock_irqsave(&tty->ctrl_lock, flags);
356 printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
359 if (task_pgrp(current) == tty->pgrp)
361 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
362 if (is_ignored(SIGTTOU))
364 if (is_current_pgrp_orphaned()) {
368 kill_pgrp(task_pgrp(current), SIGTTOU, 1);
369 set_thread_flag(TIF_SIGPENDING);
374 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
378 EXPORT_SYMBOL(tty_check_change);
380 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
381 size_t count, loff_t *ppos)
386 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
387 size_t count, loff_t *ppos)
392 /* No kernel lock held - none needed ;) */
393 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
395 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
398 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
401 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
404 static long hung_up_tty_compat_ioctl(struct file *file,
405 unsigned int cmd, unsigned long arg)
407 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
410 static const struct file_operations tty_fops = {
415 .unlocked_ioctl = tty_ioctl,
416 .compat_ioctl = tty_compat_ioctl,
418 .release = tty_release,
419 .fasync = tty_fasync,
422 static const struct file_operations console_fops = {
425 .write = redirected_tty_write,
427 .unlocked_ioctl = tty_ioctl,
428 .compat_ioctl = tty_compat_ioctl,
430 .release = tty_release,
431 .fasync = tty_fasync,
434 static const struct file_operations hung_up_tty_fops = {
436 .read = hung_up_tty_read,
437 .write = hung_up_tty_write,
438 .poll = hung_up_tty_poll,
439 .unlocked_ioctl = hung_up_tty_ioctl,
440 .compat_ioctl = hung_up_tty_compat_ioctl,
441 .release = tty_release,
444 static DEFINE_SPINLOCK(redirect_lock);
445 static struct file *redirect;
448 * tty_wakeup - request more data
451 * Internal and external helper for wakeups of tty. This function
452 * informs the line discipline if present that the driver is ready
453 * to receive more output data.
456 void tty_wakeup(struct tty_struct *tty)
458 struct tty_ldisc *ld;
460 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
461 ld = tty_ldisc_ref(tty);
463 if (ld->ops->write_wakeup)
464 ld->ops->write_wakeup(tty);
468 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
471 EXPORT_SYMBOL_GPL(tty_wakeup);
474 * tty_ldisc_flush - flush line discipline queue
477 * Flush the line discipline queue (if any) for this tty. If there
478 * is no line discipline active this is a no-op.
481 void tty_ldisc_flush(struct tty_struct *tty)
483 struct tty_ldisc *ld = tty_ldisc_ref(tty);
485 if (ld->ops->flush_buffer)
486 ld->ops->flush_buffer(tty);
489 tty_buffer_flush(tty);
492 EXPORT_SYMBOL_GPL(tty_ldisc_flush);
495 * tty_reset_termios - reset terminal state
498 * Restore a terminal to the driver default state
501 static void tty_reset_termios(struct tty_struct *tty)
503 mutex_lock(&tty->termios_mutex);
504 *tty->termios = tty->driver->init_termios;
505 tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
506 tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
507 mutex_unlock(&tty->termios_mutex);
511 * do_tty_hangup - actual handler for hangup events
514 * This can be called by the "eventd" kernel thread. That is process
515 * synchronous but doesn't hold any locks, so we need to make sure we
516 * have the appropriate locks for what we're doing.
518 * The hangup event clears any pending redirections onto the hung up
519 * device. It ensures future writes will error and it does the needed
520 * line discipline hangup and signal delivery. The tty object itself
525 * redirect lock for undoing redirection
526 * file list lock for manipulating list of ttys
527 * tty_ldisc_lock from called functions
528 * termios_mutex resetting termios data
529 * tasklist_lock to walk task list for hangup event
530 * ->siglock to protect ->signal/->sighand
532 static void do_tty_hangup(struct work_struct *work)
534 struct tty_struct *tty =
535 container_of(work, struct tty_struct, hangup_work);
536 struct file *cons_filp = NULL;
537 struct file *filp, *f = NULL;
538 struct task_struct *p;
539 struct tty_ldisc *ld;
540 int closecount = 0, n;
547 /* inuse_filps is protected by the single kernel lock */
550 spin_lock(&redirect_lock);
551 if (redirect && redirect->private_data == tty) {
555 spin_unlock(&redirect_lock);
557 check_tty_count(tty, "do_tty_hangup");
559 /* This breaks for file handles being sent over AF_UNIX sockets ? */
560 list_for_each_entry(filp, &tty->tty_files, f_u.fu_list) {
561 if (filp->f_op->write == redirected_tty_write)
563 if (filp->f_op->write != tty_write)
566 tty_fasync(-1, filp, 0); /* can't block */
567 filp->f_op = &hung_up_tty_fops;
571 * FIXME! What are the locking issues here? This may me overdoing
572 * things... This question is especially important now that we've
573 * removed the irqlock.
575 ld = tty_ldisc_ref(tty);
577 /* We may have no line discipline at this point */
578 if (ld->ops->flush_buffer)
579 ld->ops->flush_buffer(tty);
580 tty_driver_flush_buffer(tty);
581 if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) &&
582 ld->ops->write_wakeup)
583 ld->ops->write_wakeup(tty);
585 ld->ops->hangup(tty);
588 * FIXME: Once we trust the LDISC code better we can wait here for
589 * ldisc completion and fix the driver call race
591 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
592 wake_up_interruptible_poll(&tty->read_wait, POLLIN);
594 * Shutdown the current line discipline, and reset it to
597 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
598 tty_reset_termios(tty);
599 /* Defer ldisc switch */
600 /* tty_deferred_ldisc_switch(N_TTY);
602 This should get done automatically when the port closes and
603 tty_release is called */
605 read_lock(&tasklist_lock);
607 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
608 spin_lock_irq(&p->sighand->siglock);
609 if (p->signal->tty == tty) {
610 p->signal->tty = NULL;
611 /* We defer the dereferences outside fo
615 if (!p->signal->leader) {
616 spin_unlock_irq(&p->sighand->siglock);
619 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
620 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
621 put_pid(p->signal->tty_old_pgrp); /* A noop */
622 spin_lock_irqsave(&tty->ctrl_lock, flags);
624 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
625 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
626 spin_unlock_irq(&p->sighand->siglock);
627 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
629 read_unlock(&tasklist_lock);
631 spin_lock_irqsave(&tty->ctrl_lock, flags);
633 put_pid(tty->session);
637 tty->ctrl_status = 0;
638 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
640 /* Account for the p->signal references we killed */
645 * If one of the devices matches a console pointer, we
646 * cannot just call hangup() because that will cause
647 * tty->count and state->count to go out of sync.
648 * So we just call close() the right number of times.
652 for (n = 0; n < closecount; n++)
653 tty->ops->close(tty, cons_filp);
654 } else if (tty->ops->hangup)
655 (tty->ops->hangup)(tty);
657 * We don't want to have driver/ldisc interactions beyond
658 * the ones we did here. The driver layer expects no
659 * calls after ->hangup() from the ldisc side. However we
660 * can't yet guarantee all that.
662 set_bit(TTY_HUPPED, &tty->flags);
664 tty_ldisc_enable(tty);
673 * tty_hangup - trigger a hangup event
674 * @tty: tty to hangup
676 * A carrier loss (virtual or otherwise) has occurred on this like
677 * schedule a hangup sequence to run after this event.
680 void tty_hangup(struct tty_struct *tty)
682 #ifdef TTY_DEBUG_HANGUP
684 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
686 schedule_work(&tty->hangup_work);
689 EXPORT_SYMBOL(tty_hangup);
692 * tty_vhangup - process vhangup
693 * @tty: tty to hangup
695 * The user has asked via system call for the terminal to be hung up.
696 * We do this synchronously so that when the syscall returns the process
697 * is complete. That guarantee is necessary for security reasons.
700 void tty_vhangup(struct tty_struct *tty)
702 #ifdef TTY_DEBUG_HANGUP
705 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
707 do_tty_hangup(&tty->hangup_work);
710 EXPORT_SYMBOL(tty_vhangup);
713 * tty_vhangup_self - process vhangup for own ctty
715 * Perform a vhangup on the current controlling tty
718 void tty_vhangup_self(void)
720 struct tty_struct *tty;
722 tty = get_current_tty();
730 * tty_hung_up_p - was tty hung up
731 * @filp: file pointer of tty
733 * Return true if the tty has been subject to a vhangup or a carrier
737 int tty_hung_up_p(struct file *filp)
739 return (filp->f_op == &hung_up_tty_fops);
742 EXPORT_SYMBOL(tty_hung_up_p);
744 static void session_clear_tty(struct pid *session)
746 struct task_struct *p;
747 do_each_pid_task(session, PIDTYPE_SID, p) {
749 } while_each_pid_task(session, PIDTYPE_SID, p);
753 * disassociate_ctty - disconnect controlling tty
754 * @on_exit: true if exiting so need to "hang up" the session
756 * This function is typically called only by the session leader, when
757 * it wants to disassociate itself from its controlling tty.
759 * It performs the following functions:
760 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
761 * (2) Clears the tty from being controlling the session
762 * (3) Clears the controlling tty for all processes in the
765 * The argument on_exit is set to 1 if called when a process is
766 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
769 * BKL is taken for hysterical raisins
770 * tty_mutex is taken to protect tty
771 * ->siglock is taken to protect ->signal/->sighand
772 * tasklist_lock is taken to walk process list for sessions
773 * ->siglock is taken to protect ->signal/->sighand
776 void disassociate_ctty(int on_exit)
778 struct tty_struct *tty;
779 struct pid *tty_pgrp = NULL;
782 tty = get_current_tty();
784 tty_pgrp = get_pid(tty->pgrp);
786 if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY)
790 } else if (on_exit) {
791 struct pid *old_pgrp;
792 spin_lock_irq(¤t->sighand->siglock);
793 old_pgrp = current->signal->tty_old_pgrp;
794 current->signal->tty_old_pgrp = NULL;
795 spin_unlock_irq(¤t->sighand->siglock);
797 kill_pgrp(old_pgrp, SIGHUP, on_exit);
798 kill_pgrp(old_pgrp, SIGCONT, on_exit);
804 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
806 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
810 spin_lock_irq(¤t->sighand->siglock);
811 put_pid(current->signal->tty_old_pgrp);
812 current->signal->tty_old_pgrp = NULL;
813 spin_unlock_irq(¤t->sighand->siglock);
815 tty = get_current_tty();
818 spin_lock_irqsave(&tty->ctrl_lock, flags);
819 put_pid(tty->session);
823 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
826 #ifdef TTY_DEBUG_HANGUP
827 printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
832 /* Now clear signal->tty under the lock */
833 read_lock(&tasklist_lock);
834 session_clear_tty(task_session(current));
835 read_unlock(&tasklist_lock);
840 * no_tty - Ensure the current process does not have a controlling tty
844 struct task_struct *tsk = current;
846 if (tsk->signal->leader)
847 disassociate_ctty(0);
854 * stop_tty - propagate flow control
857 * Perform flow control to the driver. For PTY/TTY pairs we
858 * must also propagate the TIOCKPKT status. May be called
859 * on an already stopped device and will not re-call the driver
862 * This functionality is used by both the line disciplines for
863 * halting incoming flow and by the driver. It may therefore be
864 * called from any context, may be under the tty atomic_write_lock
868 * Uses the tty control lock internally
871 void stop_tty(struct tty_struct *tty)
874 spin_lock_irqsave(&tty->ctrl_lock, flags);
876 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
880 if (tty->link && tty->link->packet) {
881 tty->ctrl_status &= ~TIOCPKT_START;
882 tty->ctrl_status |= TIOCPKT_STOP;
883 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
885 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
887 (tty->ops->stop)(tty);
890 EXPORT_SYMBOL(stop_tty);
893 * start_tty - propagate flow control
896 * Start a tty that has been stopped if at all possible. Perform
897 * any necessary wakeups and propagate the TIOCPKT status. If this
898 * is the tty was previous stopped and is being started then the
899 * driver start method is invoked and the line discipline woken.
905 void start_tty(struct tty_struct *tty)
908 spin_lock_irqsave(&tty->ctrl_lock, flags);
909 if (!tty->stopped || tty->flow_stopped) {
910 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
914 if (tty->link && tty->link->packet) {
915 tty->ctrl_status &= ~TIOCPKT_STOP;
916 tty->ctrl_status |= TIOCPKT_START;
917 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
919 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
921 (tty->ops->start)(tty);
922 /* If we have a running line discipline it may need kicking */
926 EXPORT_SYMBOL(start_tty);
929 * tty_read - read method for tty device files
930 * @file: pointer to tty file
932 * @count: size of user buffer
935 * Perform the read system call function on this terminal device. Checks
936 * for hung up devices before calling the line discipline method.
939 * Locks the line discipline internally while needed. Multiple
940 * read calls may be outstanding in parallel.
943 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
947 struct tty_struct *tty;
949 struct tty_ldisc *ld;
951 tty = (struct tty_struct *)file->private_data;
952 inode = file->f_path.dentry->d_inode;
953 if (tty_paranoia_check(tty, inode, "tty_read"))
955 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
958 /* We want to wait for the line discipline to sort out in this
960 ld = tty_ldisc_ref_wait(tty);
962 i = (ld->ops->read)(tty, file, buf, count);
967 inode->i_atime = current_fs_time(inode->i_sb);
971 void tty_write_unlock(struct tty_struct *tty)
973 mutex_unlock(&tty->atomic_write_lock);
974 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
977 int tty_write_lock(struct tty_struct *tty, int ndelay)
979 if (!mutex_trylock(&tty->atomic_write_lock)) {
982 if (mutex_lock_interruptible(&tty->atomic_write_lock))
989 * Split writes up in sane blocksizes to avoid
990 * denial-of-service type attacks
992 static inline ssize_t do_tty_write(
993 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
994 struct tty_struct *tty,
996 const char __user *buf,
999 ssize_t ret, written = 0;
1002 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
1007 * We chunk up writes into a temporary buffer. This
1008 * simplifies low-level drivers immensely, since they
1009 * don't have locking issues and user mode accesses.
1011 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1014 * The default chunk-size is 2kB, because the NTTY
1015 * layer has problems with bigger chunks. It will
1016 * claim to be able to handle more characters than
1019 * FIXME: This can probably go away now except that 64K chunks
1020 * are too likely to fail unless switched to vmalloc...
1023 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1028 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1029 if (tty->write_cnt < chunk) {
1030 unsigned char *buf_chunk;
1035 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1040 kfree(tty->write_buf);
1041 tty->write_cnt = chunk;
1042 tty->write_buf = buf_chunk;
1045 /* Do the write .. */
1047 size_t size = count;
1051 if (copy_from_user(tty->write_buf, buf, size))
1053 ret = write(tty, file, tty->write_buf, size);
1062 if (signal_pending(current))
1067 struct inode *inode = file->f_path.dentry->d_inode;
1068 inode->i_mtime = current_fs_time(inode->i_sb);
1072 tty_write_unlock(tty);
1077 * tty_write_message - write a message to a certain tty, not just the console.
1078 * @tty: the destination tty_struct
1079 * @msg: the message to write
1081 * This is used for messages that need to be redirected to a specific tty.
1082 * We don't put it into the syslog queue right now maybe in the future if
1085 * We must still hold the BKL and test the CLOSING flag for the moment.
1088 void tty_write_message(struct tty_struct *tty, char *msg)
1092 mutex_lock(&tty->atomic_write_lock);
1093 if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags))
1094 tty->ops->write(tty, msg, strlen(msg));
1095 tty_write_unlock(tty);
1103 * tty_write - write method for tty device file
1104 * @file: tty file pointer
1105 * @buf: user data to write
1106 * @count: bytes to write
1109 * Write data to a tty device via the line discipline.
1112 * Locks the line discipline as required
1113 * Writes to the tty driver are serialized by the atomic_write_lock
1114 * and are then processed in chunks to the device. The line discipline
1115 * write method will not be invoked in parallel for each device.
1118 static ssize_t tty_write(struct file *file, const char __user *buf,
1119 size_t count, loff_t *ppos)
1121 struct tty_struct *tty;
1122 struct inode *inode = file->f_path.dentry->d_inode;
1124 struct tty_ldisc *ld;
1126 tty = (struct tty_struct *)file->private_data;
1127 if (tty_paranoia_check(tty, inode, "tty_write"))
1129 if (!tty || !tty->ops->write ||
1130 (test_bit(TTY_IO_ERROR, &tty->flags)))
1132 /* Short term debug to catch buggy drivers */
1133 if (tty->ops->write_room == NULL)
1134 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1136 ld = tty_ldisc_ref_wait(tty);
1137 if (!ld->ops->write)
1140 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1141 tty_ldisc_deref(ld);
1145 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1146 size_t count, loff_t *ppos)
1148 struct file *p = NULL;
1150 spin_lock(&redirect_lock);
1155 spin_unlock(&redirect_lock);
1159 res = vfs_write(p, buf, count, &p->f_pos);
1163 return tty_write(file, buf, count, ppos);
1166 static char ptychar[] = "pqrstuvwxyzabcde";
1169 * pty_line_name - generate name for a pty
1170 * @driver: the tty driver in use
1171 * @index: the minor number
1172 * @p: output buffer of at least 6 bytes
1174 * Generate a name from a driver reference and write it to the output
1179 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1181 int i = index + driver->name_base;
1182 /* ->name is initialized to "ttyp", but "tty" is expected */
1183 sprintf(p, "%s%c%x",
1184 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1185 ptychar[i >> 4 & 0xf], i & 0xf);
1189 * tty_line_name - generate name for a tty
1190 * @driver: the tty driver in use
1191 * @index: the minor number
1192 * @p: output buffer of at least 7 bytes
1194 * Generate a name from a driver reference and write it to the output
1199 static void tty_line_name(struct tty_driver *driver, int index, char *p)
1201 sprintf(p, "%s%d", driver->name, index + driver->name_base);
1205 * tty_driver_lookup_tty() - find an existing tty, if any
1206 * @driver: the driver for the tty
1207 * @idx: the minor number
1209 * Return the tty, if found or ERR_PTR() otherwise.
1211 * Locking: tty_mutex must be held. If tty is found, the mutex must
1212 * be held until the 'fast-open' is also done. Will change once we
1213 * have refcounting in the driver and per driver locking
1215 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1216 struct inode *inode, int idx)
1218 struct tty_struct *tty;
1220 if (driver->ops->lookup)
1221 return driver->ops->lookup(driver, inode, idx);
1223 tty = driver->ttys[idx];
1228 * tty_init_termios - helper for termios setup
1229 * @tty: the tty to set up
1231 * Initialise the termios structures for this tty. Thus runs under
1232 * the tty_mutex currently so we can be relaxed about ordering.
1235 int tty_init_termios(struct tty_struct *tty)
1237 struct ktermios *tp;
1238 int idx = tty->index;
1240 tp = tty->driver->termios[idx];
1242 tp = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
1245 memcpy(tp, &tty->driver->init_termios,
1246 sizeof(struct ktermios));
1247 tty->driver->termios[idx] = tp;
1250 tty->termios_locked = tp + 1;
1252 /* Compatibility until drivers always set this */
1253 tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
1254 tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
1259 * tty_driver_install_tty() - install a tty entry in the driver
1260 * @driver: the driver for the tty
1263 * Install a tty object into the driver tables. The tty->index field
1264 * will be set by the time this is called. This method is responsible
1265 * for ensuring any need additional structures are allocated and
1268 * Locking: tty_mutex for now
1270 static int tty_driver_install_tty(struct tty_driver *driver,
1271 struct tty_struct *tty)
1273 int idx = tty->index;
1275 if (driver->ops->install)
1276 return driver->ops->install(driver, tty);
1278 if (tty_init_termios(tty) == 0) {
1279 tty_driver_kref_get(driver);
1281 driver->ttys[idx] = tty;
1288 * tty_driver_remove_tty() - remove a tty from the driver tables
1289 * @driver: the driver for the tty
1290 * @idx: the minor number
1292 * Remvoe a tty object from the driver tables. The tty->index field
1293 * will be set by the time this is called.
1295 * Locking: tty_mutex for now
1297 static void tty_driver_remove_tty(struct tty_driver *driver,
1298 struct tty_struct *tty)
1300 if (driver->ops->remove)
1301 driver->ops->remove(driver, tty);
1303 driver->ttys[tty->index] = NULL;
1307 * tty_reopen() - fast re-open of an open tty
1308 * @tty - the tty to open
1310 * Return 0 on success, -errno on error.
1312 * Locking: tty_mutex must be held from the time the tty was found
1313 * till this open completes.
1315 static int tty_reopen(struct tty_struct *tty)
1317 struct tty_driver *driver = tty->driver;
1319 if (test_bit(TTY_CLOSING, &tty->flags))
1322 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1323 driver->subtype == PTY_TYPE_MASTER) {
1325 * special case for PTY masters: only one open permitted,
1326 * and the slave side open count is incremented as well.
1334 tty->driver = driver; /* N.B. why do this every time?? */
1336 WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
1342 * tty_init_dev - initialise a tty device
1343 * @driver: tty driver we are opening a device on
1344 * @idx: device index
1345 * @ret_tty: returned tty structure
1346 * @first_ok: ok to open a new device (used by ptmx)
1348 * Prepare a tty device. This may not be a "new" clean device but
1349 * could also be an active device. The pty drivers require special
1350 * handling because of this.
1353 * The function is called under the tty_mutex, which
1354 * protects us from the tty struct or driver itself going away.
1356 * On exit the tty device has the line discipline attached and
1357 * a reference count of 1. If a pair was created for pty/tty use
1358 * and the other was a pty master then it too has a reference count of 1.
1360 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1361 * failed open. The new code protects the open with a mutex, so it's
1362 * really quite straightforward. The mutex locking can probably be
1363 * relaxed for the (most common) case of reopening a tty.
1366 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx,
1369 struct tty_struct *tty;
1372 /* Check if pty master is being opened multiple times */
1373 if (driver->subtype == PTY_TYPE_MASTER &&
1374 (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok)
1375 return ERR_PTR(-EIO);
1378 * First time open is complex, especially for PTY devices.
1379 * This code guarantees that either everything succeeds and the
1380 * TTY is ready for operation, or else the table slots are vacated
1381 * and the allocated memory released. (Except that the termios
1382 * and locked termios may be retained.)
1385 if (!try_module_get(driver->owner))
1386 return ERR_PTR(-ENODEV);
1388 tty = alloc_tty_struct();
1391 initialize_tty_struct(tty, driver, idx);
1393 retval = tty_driver_install_tty(driver, tty);
1395 free_tty_struct(tty);
1396 module_put(driver->owner);
1397 return ERR_PTR(retval);
1401 * Structures all installed ... call the ldisc open routines.
1402 * If we fail here just call release_tty to clean up. No need
1403 * to decrement the use counts, as release_tty doesn't care.
1406 retval = tty_ldisc_setup(tty, tty->link);
1408 goto release_mem_out;
1412 module_put(driver->owner);
1413 return ERR_PTR(-ENOMEM);
1415 /* call the tty release_tty routine to clean out this slot */
1417 if (printk_ratelimit())
1418 printk(KERN_INFO "tty_init_dev: ldisc open failed, "
1419 "clearing slot %d\n", idx);
1420 release_tty(tty, idx);
1421 return ERR_PTR(retval);
1424 void tty_free_termios(struct tty_struct *tty)
1426 struct ktermios *tp;
1427 int idx = tty->index;
1428 /* Kill this flag and push into drivers for locking etc */
1429 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
1430 /* FIXME: Locking on ->termios array */
1432 tty->driver->termios[idx] = NULL;
1436 EXPORT_SYMBOL(tty_free_termios);
1438 void tty_shutdown(struct tty_struct *tty)
1440 tty_driver_remove_tty(tty->driver, tty);
1441 tty_free_termios(tty);
1443 EXPORT_SYMBOL(tty_shutdown);
1446 * release_one_tty - release tty structure memory
1447 * @kref: kref of tty we are obliterating
1449 * Releases memory associated with a tty structure, and clears out the
1450 * driver table slots. This function is called when a device is no longer
1451 * in use. It also gets called when setup of a device fails.
1454 * tty_mutex - sometimes only
1455 * takes the file list lock internally when working on the list
1456 * of ttys that the driver keeps.
1458 static void release_one_tty(struct kref *kref)
1460 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1461 struct tty_driver *driver = tty->driver;
1463 if (tty->ops->shutdown)
1464 tty->ops->shutdown(tty);
1468 tty_driver_kref_put(driver);
1469 module_put(driver->owner);
1472 list_del_init(&tty->tty_files);
1475 free_tty_struct(tty);
1479 * tty_kref_put - release a tty kref
1482 * Release a reference to a tty device and if need be let the kref
1483 * layer destruct the object for us
1486 void tty_kref_put(struct tty_struct *tty)
1489 kref_put(&tty->kref, release_one_tty);
1491 EXPORT_SYMBOL(tty_kref_put);
1494 * release_tty - release tty structure memory
1496 * Release both @tty and a possible linked partner (think pty pair),
1497 * and decrement the refcount of the backing module.
1500 * tty_mutex - sometimes only
1501 * takes the file list lock internally when working on the list
1502 * of ttys that the driver keeps.
1503 * FIXME: should we require tty_mutex is held here ??
1506 static void release_tty(struct tty_struct *tty, int idx)
1508 /* This should always be true but check for the moment */
1509 WARN_ON(tty->index != idx);
1512 tty_kref_put(tty->link);
1517 * Even releasing the tty structures is a tricky business.. We have
1518 * to be very careful that the structures are all released at the
1519 * same time, as interrupts might otherwise get the wrong pointers.
1521 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1522 * lead to double frees or releasing memory still in use.
1524 void tty_release_dev(struct file *filp)
1526 struct tty_struct *tty, *o_tty;
1527 int pty_master, tty_closing, o_tty_closing, do_sleep;
1531 struct inode *inode;
1533 inode = filp->f_path.dentry->d_inode;
1534 tty = (struct tty_struct *)filp->private_data;
1535 if (tty_paranoia_check(tty, inode, "tty_release_dev"))
1538 check_tty_count(tty, "tty_release_dev");
1540 tty_fasync(-1, filp, 0);
1543 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1544 tty->driver->subtype == PTY_TYPE_MASTER);
1545 devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
1548 #ifdef TTY_PARANOIA_CHECK
1549 if (idx < 0 || idx >= tty->driver->num) {
1550 printk(KERN_DEBUG "tty_release_dev: bad idx when trying to "
1551 "free (%s)\n", tty->name);
1555 if (tty != tty->driver->ttys[idx]) {
1556 printk(KERN_DEBUG "tty_release_dev: driver.table[%d] not tty "
1557 "for (%s)\n", idx, tty->name);
1560 if (tty->termios != tty->driver->termios[idx]) {
1561 printk(KERN_DEBUG "tty_release_dev: driver.termios[%d] not termios "
1569 #ifdef TTY_DEBUG_HANGUP
1570 printk(KERN_DEBUG "tty_release_dev of %s (tty count=%d)...",
1571 tty_name(tty, buf), tty->count);
1574 #ifdef TTY_PARANOIA_CHECK
1575 if (tty->driver->other &&
1576 !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
1577 if (o_tty != tty->driver->other->ttys[idx]) {
1578 printk(KERN_DEBUG "tty_release_dev: other->table[%d] "
1579 "not o_tty for (%s)\n",
1583 if (o_tty->termios != tty->driver->other->termios[idx]) {
1584 printk(KERN_DEBUG "tty_release_dev: other->termios[%d] "
1585 "not o_termios for (%s)\n",
1589 if (o_tty->link != tty) {
1590 printk(KERN_DEBUG "tty_release_dev: bad pty pointers\n");
1595 if (tty->ops->close)
1596 tty->ops->close(tty, filp);
1599 * Sanity check: if tty->count is going to zero, there shouldn't be
1600 * any waiters on tty->read_wait or tty->write_wait. We test the
1601 * wait queues and kick everyone out _before_ actually starting to
1602 * close. This ensures that we won't block while releasing the tty
1605 * The test for the o_tty closing is necessary, since the master and
1606 * slave sides may close in any order. If the slave side closes out
1607 * first, its count will be one, since the master side holds an open.
1608 * Thus this test wouldn't be triggered at the time the slave closes,
1611 * Note that it's possible for the tty to be opened again while we're
1612 * flushing out waiters. By recalculating the closing flags before
1613 * each iteration we avoid any problems.
1616 /* Guard against races with tty->count changes elsewhere and
1617 opens on /dev/tty */
1619 mutex_lock(&tty_mutex);
1620 tty_closing = tty->count <= 1;
1621 o_tty_closing = o_tty &&
1622 (o_tty->count <= (pty_master ? 1 : 0));
1626 if (waitqueue_active(&tty->read_wait)) {
1627 wake_up_poll(&tty->read_wait, POLLIN);
1630 if (waitqueue_active(&tty->write_wait)) {
1631 wake_up_poll(&tty->write_wait, POLLOUT);
1635 if (o_tty_closing) {
1636 if (waitqueue_active(&o_tty->read_wait)) {
1637 wake_up_poll(&o_tty->read_wait, POLLIN);
1640 if (waitqueue_active(&o_tty->write_wait)) {
1641 wake_up_poll(&o_tty->write_wait, POLLOUT);
1648 printk(KERN_WARNING "tty_release_dev: %s: read/write wait queue "
1649 "active!\n", tty_name(tty, buf));
1650 mutex_unlock(&tty_mutex);
1655 * The closing flags are now consistent with the open counts on
1656 * both sides, and we've completed the last operation that could
1657 * block, so it's safe to proceed with closing.
1660 if (--o_tty->count < 0) {
1661 printk(KERN_WARNING "tty_release_dev: bad pty slave count "
1663 o_tty->count, tty_name(o_tty, buf));
1667 if (--tty->count < 0) {
1668 printk(KERN_WARNING "tty_release_dev: bad tty->count (%d) for %s\n",
1669 tty->count, tty_name(tty, buf));
1674 * We've decremented tty->count, so we need to remove this file
1675 * descriptor off the tty->tty_files list; this serves two
1677 * - check_tty_count sees the correct number of file descriptors
1678 * associated with this tty.
1679 * - do_tty_hangup no longer sees this file descriptor as
1680 * something that needs to be handled for hangups.
1683 filp->private_data = NULL;
1686 * Perform some housekeeping before deciding whether to return.
1688 * Set the TTY_CLOSING flag if this was the last open. In the
1689 * case of a pty we may have to wait around for the other side
1690 * to close, and TTY_CLOSING makes sure we can't be reopened.
1693 set_bit(TTY_CLOSING, &tty->flags);
1695 set_bit(TTY_CLOSING, &o_tty->flags);
1698 * If _either_ side is closing, make sure there aren't any
1699 * processes that still think tty or o_tty is their controlling
1702 if (tty_closing || o_tty_closing) {
1703 read_lock(&tasklist_lock);
1704 session_clear_tty(tty->session);
1706 session_clear_tty(o_tty->session);
1707 read_unlock(&tasklist_lock);
1710 mutex_unlock(&tty_mutex);
1712 /* check whether both sides are closing ... */
1713 if (!tty_closing || (o_tty && !o_tty_closing))
1716 #ifdef TTY_DEBUG_HANGUP
1717 printk(KERN_DEBUG "freeing tty structure...");
1720 * Ask the line discipline code to release its structures
1722 tty_ldisc_release(tty, o_tty);
1724 * The release_tty function takes care of the details of clearing
1725 * the slots and preserving the termios structure.
1727 release_tty(tty, idx);
1729 /* Make this pty number available for reallocation */
1731 devpts_kill_index(inode, idx);
1735 * __tty_open - open a tty device
1736 * @inode: inode of device file
1737 * @filp: file pointer to tty
1739 * tty_open and tty_release keep up the tty count that contains the
1740 * number of opens done on a tty. We cannot use the inode-count, as
1741 * different inodes might point to the same tty.
1743 * Open-counting is needed for pty masters, as well as for keeping
1744 * track of serial lines: DTR is dropped when the last close happens.
1745 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1747 * The termios state of a pty is reset on first open so that
1748 * settings don't persist across reuse.
1750 * Locking: tty_mutex protects tty, get_tty_driver and tty_init_dev work.
1751 * tty->count should protect the rest.
1752 * ->siglock protects ->signal/->sighand
1755 static int __tty_open(struct inode *inode, struct file *filp)
1757 struct tty_struct *tty = NULL;
1759 struct tty_driver *driver;
1761 dev_t device = inode->i_rdev;
1762 unsigned saved_flags = filp->f_flags;
1764 nonseekable_open(inode, filp);
1767 noctty = filp->f_flags & O_NOCTTY;
1771 mutex_lock(&tty_mutex);
1773 if (device == MKDEV(TTYAUX_MAJOR, 0)) {
1774 tty = get_current_tty();
1776 mutex_unlock(&tty_mutex);
1779 driver = tty_driver_kref_get(tty->driver);
1781 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1783 /* FIXME: Should we take a driver reference ? */
1788 if (device == MKDEV(TTY_MAJOR, 0)) {
1789 extern struct tty_driver *console_driver;
1790 driver = tty_driver_kref_get(console_driver);
1796 if (device == MKDEV(TTYAUX_MAJOR, 1)) {
1797 struct tty_driver *console_driver = console_device(&index);
1798 if (console_driver) {
1799 driver = tty_driver_kref_get(console_driver);
1801 /* Don't let /dev/console block */
1802 filp->f_flags |= O_NONBLOCK;
1807 mutex_unlock(&tty_mutex);
1811 driver = get_tty_driver(device, &index);
1813 mutex_unlock(&tty_mutex);
1818 /* check whether we're reopening an existing tty */
1819 tty = tty_driver_lookup_tty(driver, inode, index);
1822 mutex_unlock(&tty_mutex);
1823 return PTR_ERR(tty);
1828 retval = tty_reopen(tty);
1830 tty = ERR_PTR(retval);
1832 tty = tty_init_dev(driver, index, 0);
1834 mutex_unlock(&tty_mutex);
1835 tty_driver_kref_put(driver);
1837 return PTR_ERR(tty);
1839 filp->private_data = tty;
1840 file_move(filp, &tty->tty_files);
1841 check_tty_count(tty, "tty_open");
1842 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1843 tty->driver->subtype == PTY_TYPE_MASTER)
1845 #ifdef TTY_DEBUG_HANGUP
1846 printk(KERN_DEBUG "opening %s...", tty->name);
1850 retval = tty->ops->open(tty, filp);
1854 filp->f_flags = saved_flags;
1856 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
1857 !capable(CAP_SYS_ADMIN))
1861 #ifdef TTY_DEBUG_HANGUP
1862 printk(KERN_DEBUG "error %d in opening %s...", retval,
1865 tty_release_dev(filp);
1866 if (retval != -ERESTARTSYS)
1868 if (signal_pending(current))
1872 * Need to reset f_op in case a hangup happened.
1874 if (filp->f_op == &hung_up_tty_fops)
1875 filp->f_op = &tty_fops;
1879 mutex_lock(&tty_mutex);
1880 spin_lock_irq(¤t->sighand->siglock);
1882 current->signal->leader &&
1883 !current->signal->tty &&
1884 tty->session == NULL)
1885 __proc_set_tty(current, tty);
1886 spin_unlock_irq(¤t->sighand->siglock);
1887 mutex_unlock(&tty_mutex);
1891 /* BKL pushdown: scary code avoidance wrapper */
1892 static int tty_open(struct inode *inode, struct file *filp)
1897 ret = __tty_open(inode, filp);
1906 * tty_release - vfs callback for close
1907 * @inode: inode of tty
1908 * @filp: file pointer for handle to tty
1910 * Called the last time each file handle is closed that references
1911 * this tty. There may however be several such references.
1914 * Takes bkl. See tty_release_dev
1917 static int tty_release(struct inode *inode, struct file *filp)
1920 tty_release_dev(filp);
1926 * tty_poll - check tty status
1927 * @filp: file being polled
1928 * @wait: poll wait structures to update
1930 * Call the line discipline polling method to obtain the poll
1931 * status of the device.
1933 * Locking: locks called line discipline but ldisc poll method
1934 * may be re-entered freely by other callers.
1937 static unsigned int tty_poll(struct file *filp, poll_table *wait)
1939 struct tty_struct *tty;
1940 struct tty_ldisc *ld;
1943 tty = (struct tty_struct *)filp->private_data;
1944 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll"))
1947 ld = tty_ldisc_ref_wait(tty);
1949 ret = (ld->ops->poll)(tty, filp, wait);
1950 tty_ldisc_deref(ld);
1954 static int tty_fasync(int fd, struct file *filp, int on)
1956 struct tty_struct *tty;
1957 unsigned long flags;
1961 tty = (struct tty_struct *)filp->private_data;
1962 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
1965 retval = fasync_helper(fd, filp, on, &tty->fasync);
1972 if (!waitqueue_active(&tty->read_wait))
1973 tty->minimum_to_wake = 1;
1974 spin_lock_irqsave(&tty->ctrl_lock, flags);
1977 type = PIDTYPE_PGID;
1979 pid = task_pid(current);
1982 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
1983 retval = __f_setown(filp, pid, type, 0);
1987 if (!tty->fasync && !waitqueue_active(&tty->read_wait))
1988 tty->minimum_to_wake = N_TTY_BUF_SIZE;
1997 * tiocsti - fake input character
1998 * @tty: tty to fake input into
1999 * @p: pointer to character
2001 * Fake input to a tty device. Does the necessary locking and
2004 * FIXME: does not honour flow control ??
2007 * Called functions take tty_ldisc_lock
2008 * current->signal->tty check is safe without locks
2010 * FIXME: may race normal receive processing
2013 static int tiocsti(struct tty_struct *tty, char __user *p)
2016 struct tty_ldisc *ld;
2018 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2020 if (get_user(ch, p))
2022 tty_audit_tiocsti(tty, ch);
2023 ld = tty_ldisc_ref_wait(tty);
2024 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2025 tty_ldisc_deref(ld);
2030 * tiocgwinsz - implement window query ioctl
2032 * @arg: user buffer for result
2034 * Copies the kernel idea of the window size into the user buffer.
2036 * Locking: tty->termios_mutex is taken to ensure the winsize data
2040 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2044 mutex_lock(&tty->termios_mutex);
2045 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2046 mutex_unlock(&tty->termios_mutex);
2048 return err ? -EFAULT: 0;
2052 * tty_do_resize - resize event
2053 * @tty: tty being resized
2054 * @rows: rows (character)
2055 * @cols: cols (character)
2057 * Update the termios variables and send the neccessary signals to
2058 * peform a terminal resize correctly
2061 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2064 unsigned long flags;
2067 mutex_lock(&tty->termios_mutex);
2068 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2070 /* Get the PID values and reference them so we can
2071 avoid holding the tty ctrl lock while sending signals */
2072 spin_lock_irqsave(&tty->ctrl_lock, flags);
2073 pgrp = get_pid(tty->pgrp);
2074 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2077 kill_pgrp(pgrp, SIGWINCH, 1);
2082 mutex_unlock(&tty->termios_mutex);
2087 * tiocswinsz - implement window size set ioctl
2088 * @tty; tty side of tty
2089 * @arg: user buffer for result
2091 * Copies the user idea of the window size to the kernel. Traditionally
2092 * this is just advisory information but for the Linux console it
2093 * actually has driver level meaning and triggers a VC resize.
2096 * Driver dependant. The default do_resize method takes the
2097 * tty termios mutex and ctrl_lock. The console takes its own lock
2098 * then calls into the default method.
2101 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2103 struct winsize tmp_ws;
2104 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2107 if (tty->ops->resize)
2108 return tty->ops->resize(tty, &tmp_ws);
2110 return tty_do_resize(tty, &tmp_ws);
2114 * tioccons - allow admin to move logical console
2115 * @file: the file to become console
2117 * Allow the adminstrator to move the redirected console device
2119 * Locking: uses redirect_lock to guard the redirect information
2122 static int tioccons(struct file *file)
2124 if (!capable(CAP_SYS_ADMIN))
2126 if (file->f_op->write == redirected_tty_write) {
2128 spin_lock(&redirect_lock);
2131 spin_unlock(&redirect_lock);
2136 spin_lock(&redirect_lock);
2138 spin_unlock(&redirect_lock);
2143 spin_unlock(&redirect_lock);
2148 * fionbio - non blocking ioctl
2149 * @file: file to set blocking value
2150 * @p: user parameter
2152 * Historical tty interfaces had a blocking control ioctl before
2153 * the generic functionality existed. This piece of history is preserved
2154 * in the expected tty API of posix OS's.
2156 * Locking: none, the open fle handle ensures it won't go away.
2159 static int fionbio(struct file *file, int __user *p)
2163 if (get_user(nonblock, p))
2166 spin_lock(&file->f_lock);
2168 file->f_flags |= O_NONBLOCK;
2170 file->f_flags &= ~O_NONBLOCK;
2171 spin_unlock(&file->f_lock);
2176 * tiocsctty - set controlling tty
2177 * @tty: tty structure
2178 * @arg: user argument
2180 * This ioctl is used to manage job control. It permits a session
2181 * leader to set this tty as the controlling tty for the session.
2184 * Takes tty_mutex() to protect tty instance
2185 * Takes tasklist_lock internally to walk sessions
2186 * Takes ->siglock() when updating signal->tty
2189 static int tiocsctty(struct tty_struct *tty, int arg)
2192 if (current->signal->leader && (task_session(current) == tty->session))
2195 mutex_lock(&tty_mutex);
2197 * The process must be a session leader and
2198 * not have a controlling tty already.
2200 if (!current->signal->leader || current->signal->tty) {
2207 * This tty is already the controlling
2208 * tty for another session group!
2210 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2214 read_lock(&tasklist_lock);
2215 session_clear_tty(tty->session);
2216 read_unlock(&tasklist_lock);
2222 proc_set_tty(current, tty);
2224 mutex_unlock(&tty_mutex);
2229 * tty_get_pgrp - return a ref counted pgrp pid
2232 * Returns a refcounted instance of the pid struct for the process
2233 * group controlling the tty.
2236 struct pid *tty_get_pgrp(struct tty_struct *tty)
2238 unsigned long flags;
2241 spin_lock_irqsave(&tty->ctrl_lock, flags);
2242 pgrp = get_pid(tty->pgrp);
2243 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2247 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2250 * tiocgpgrp - get process group
2251 * @tty: tty passed by user
2252 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2255 * Obtain the process group of the tty. If there is no process group
2258 * Locking: none. Reference to current->signal->tty is safe.
2261 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2266 * (tty == real_tty) is a cheap way of
2267 * testing if the tty is NOT a master pty.
2269 if (tty == real_tty && current->signal->tty != real_tty)
2271 pid = tty_get_pgrp(real_tty);
2272 ret = put_user(pid_vnr(pid), p);
2278 * tiocspgrp - attempt to set process group
2279 * @tty: tty passed by user
2280 * @real_tty: tty side device matching tty passed by user
2283 * Set the process group of the tty to the session passed. Only
2284 * permitted where the tty session is our session.
2286 * Locking: RCU, ctrl lock
2289 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2293 int retval = tty_check_change(real_tty);
2294 unsigned long flags;
2300 if (!current->signal->tty ||
2301 (current->signal->tty != real_tty) ||
2302 (real_tty->session != task_session(current)))
2304 if (get_user(pgrp_nr, p))
2309 pgrp = find_vpid(pgrp_nr);
2314 if (session_of_pgrp(pgrp) != task_session(current))
2317 spin_lock_irqsave(&tty->ctrl_lock, flags);
2318 put_pid(real_tty->pgrp);
2319 real_tty->pgrp = get_pid(pgrp);
2320 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2327 * tiocgsid - get session id
2328 * @tty: tty passed by user
2329 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2330 * @p: pointer to returned session id
2332 * Obtain the session id of the tty. If there is no session
2335 * Locking: none. Reference to current->signal->tty is safe.
2338 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2341 * (tty == real_tty) is a cheap way of
2342 * testing if the tty is NOT a master pty.
2344 if (tty == real_tty && current->signal->tty != real_tty)
2346 if (!real_tty->session)
2348 return put_user(pid_vnr(real_tty->session), p);
2352 * tiocsetd - set line discipline
2354 * @p: pointer to user data
2356 * Set the line discipline according to user request.
2358 * Locking: see tty_set_ldisc, this function is just a helper
2361 static int tiocsetd(struct tty_struct *tty, int __user *p)
2366 if (get_user(ldisc, p))
2370 ret = tty_set_ldisc(tty, ldisc);
2377 * send_break - performed time break
2378 * @tty: device to break on
2379 * @duration: timeout in mS
2381 * Perform a timed break on hardware that lacks its own driver level
2382 * timed break functionality.
2385 * atomic_write_lock serializes
2389 static int send_break(struct tty_struct *tty, unsigned int duration)
2393 if (tty->ops->break_ctl == NULL)
2396 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2397 retval = tty->ops->break_ctl(tty, duration);
2399 /* Do the work ourselves */
2400 if (tty_write_lock(tty, 0) < 0)
2402 retval = tty->ops->break_ctl(tty, -1);
2405 if (!signal_pending(current))
2406 msleep_interruptible(duration);
2407 retval = tty->ops->break_ctl(tty, 0);
2409 tty_write_unlock(tty);
2410 if (signal_pending(current))
2417 * tty_tiocmget - get modem status
2419 * @file: user file pointer
2420 * @p: pointer to result
2422 * Obtain the modem status bits from the tty driver if the feature
2423 * is supported. Return -EINVAL if it is not available.
2425 * Locking: none (up to the driver)
2428 static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p)
2430 int retval = -EINVAL;
2432 if (tty->ops->tiocmget) {
2433 retval = tty->ops->tiocmget(tty, file);
2436 retval = put_user(retval, p);
2442 * tty_tiocmset - set modem status
2444 * @file: user file pointer
2445 * @cmd: command - clear bits, set bits or set all
2446 * @p: pointer to desired bits
2448 * Set the modem status bits from the tty driver if the feature
2449 * is supported. Return -EINVAL if it is not available.
2451 * Locking: none (up to the driver)
2454 static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int cmd,
2458 unsigned int set, clear, val;
2460 if (tty->ops->tiocmset == NULL)
2463 retval = get_user(val, p);
2479 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2480 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2481 return tty->ops->tiocmset(tty, file, set, clear);
2485 * Split this up, as gcc can choke on it otherwise..
2487 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2489 struct tty_struct *tty, *real_tty;
2490 void __user *p = (void __user *)arg;
2492 struct tty_ldisc *ld;
2493 struct inode *inode = file->f_dentry->d_inode;
2495 tty = (struct tty_struct *)file->private_data;
2496 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2500 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2501 tty->driver->subtype == PTY_TYPE_MASTER)
2502 real_tty = tty->link;
2506 * Factor out some common prep work
2514 retval = tty_check_change(tty);
2517 if (cmd != TIOCCBRK) {
2518 tty_wait_until_sent(tty, 0);
2519 if (signal_pending(current))
2530 return tiocsti(tty, p);
2532 return tiocgwinsz(real_tty, p);
2534 return tiocswinsz(real_tty, p);
2536 return real_tty != tty ? -EINVAL : tioccons(file);
2538 return fionbio(file, p);
2540 set_bit(TTY_EXCLUSIVE, &tty->flags);
2543 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2546 if (current->signal->tty != tty)
2551 return tiocsctty(tty, arg);
2553 return tiocgpgrp(tty, real_tty, p);
2555 return tiocspgrp(tty, real_tty, p);
2557 return tiocgsid(tty, real_tty, p);
2559 return put_user(tty->ldisc.ops->num, (int __user *)p);
2561 return tiocsetd(tty, p);
2565 case TIOCSBRK: /* Turn break on, unconditionally */
2566 if (tty->ops->break_ctl)
2567 return tty->ops->break_ctl(tty, -1);
2569 case TIOCCBRK: /* Turn break off, unconditionally */
2570 if (tty->ops->break_ctl)
2571 return tty->ops->break_ctl(tty, 0);
2573 case TCSBRK: /* SVID version: non-zero arg --> no break */
2574 /* non-zero arg means wait for all output data
2575 * to be sent (performed above) but don't send break.
2576 * This is used by the tcdrain() termios function.
2579 return send_break(tty, 250);
2581 case TCSBRKP: /* support for POSIX tcsendbreak() */
2582 return send_break(tty, arg ? arg*100 : 250);
2585 return tty_tiocmget(tty, file, p);
2589 return tty_tiocmset(tty, file, cmd, p);
2594 /* flush tty buffer and allow ldisc to process ioctl */
2595 tty_buffer_flush(tty);
2600 if (tty->ops->ioctl) {
2601 retval = (tty->ops->ioctl)(tty, file, cmd, arg);
2602 if (retval != -ENOIOCTLCMD)
2605 ld = tty_ldisc_ref_wait(tty);
2607 if (ld->ops->ioctl) {
2608 retval = ld->ops->ioctl(tty, file, cmd, arg);
2609 if (retval == -ENOIOCTLCMD)
2612 tty_ldisc_deref(ld);
2616 #ifdef CONFIG_COMPAT
2617 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2620 struct inode *inode = file->f_dentry->d_inode;
2621 struct tty_struct *tty = file->private_data;
2622 struct tty_ldisc *ld;
2623 int retval = -ENOIOCTLCMD;
2625 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2628 if (tty->ops->compat_ioctl) {
2629 retval = (tty->ops->compat_ioctl)(tty, file, cmd, arg);
2630 if (retval != -ENOIOCTLCMD)
2634 ld = tty_ldisc_ref_wait(tty);
2635 if (ld->ops->compat_ioctl)
2636 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2637 tty_ldisc_deref(ld);
2644 * This implements the "Secure Attention Key" --- the idea is to
2645 * prevent trojan horses by killing all processes associated with this
2646 * tty when the user hits the "Secure Attention Key". Required for
2647 * super-paranoid applications --- see the Orange Book for more details.
2649 * This code could be nicer; ideally it should send a HUP, wait a few
2650 * seconds, then send a INT, and then a KILL signal. But you then
2651 * have to coordinate with the init process, since all processes associated
2652 * with the current tty must be dead before the new getty is allowed
2655 * Now, if it would be correct ;-/ The current code has a nasty hole -
2656 * it doesn't catch files in flight. We may send the descriptor to ourselves
2657 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2659 * Nasty bug: do_SAK is being called in interrupt context. This can
2660 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2662 void __do_SAK(struct tty_struct *tty)
2667 struct task_struct *g, *p;
2668 struct pid *session;
2671 struct fdtable *fdt;
2675 session = tty->session;
2677 tty_ldisc_flush(tty);
2679 tty_driver_flush_buffer(tty);
2681 read_lock(&tasklist_lock);
2682 /* Kill the entire session */
2683 do_each_pid_task(session, PIDTYPE_SID, p) {
2684 printk(KERN_NOTICE "SAK: killed process %d"
2685 " (%s): task_session(p)==tty->session\n",
2686 task_pid_nr(p), p->comm);
2687 send_sig(SIGKILL, p, 1);
2688 } while_each_pid_task(session, PIDTYPE_SID, p);
2689 /* Now kill any processes that happen to have the
2692 do_each_thread(g, p) {
2693 if (p->signal->tty == tty) {
2694 printk(KERN_NOTICE "SAK: killed process %d"
2695 " (%s): task_session(p)==tty->session\n",
2696 task_pid_nr(p), p->comm);
2697 send_sig(SIGKILL, p, 1);
2703 * We don't take a ref to the file, so we must
2704 * hold ->file_lock instead.
2706 spin_lock(&p->files->file_lock);
2707 fdt = files_fdtable(p->files);
2708 for (i = 0; i < fdt->max_fds; i++) {
2709 filp = fcheck_files(p->files, i);
2712 if (filp->f_op->read == tty_read &&
2713 filp->private_data == tty) {
2714 printk(KERN_NOTICE "SAK: killed process %d"
2715 " (%s): fd#%d opened to the tty\n",
2716 task_pid_nr(p), p->comm, i);
2717 force_sig(SIGKILL, p);
2721 spin_unlock(&p->files->file_lock);
2724 } while_each_thread(g, p);
2725 read_unlock(&tasklist_lock);
2729 static void do_SAK_work(struct work_struct *work)
2731 struct tty_struct *tty =
2732 container_of(work, struct tty_struct, SAK_work);
2737 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2738 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2739 * the values which we write to it will be identical to the values which it
2740 * already has. --akpm
2742 void do_SAK(struct tty_struct *tty)
2746 schedule_work(&tty->SAK_work);
2749 EXPORT_SYMBOL(do_SAK);
2752 * initialize_tty_struct
2753 * @tty: tty to initialize
2755 * This subroutine initializes a tty structure that has been newly
2758 * Locking: none - tty in question must not be exposed at this point
2761 void initialize_tty_struct(struct tty_struct *tty,
2762 struct tty_driver *driver, int idx)
2764 memset(tty, 0, sizeof(struct tty_struct));
2765 kref_init(&tty->kref);
2766 tty->magic = TTY_MAGIC;
2767 tty_ldisc_init(tty);
2768 tty->session = NULL;
2770 tty->overrun_time = jiffies;
2771 tty->buf.head = tty->buf.tail = NULL;
2772 tty_buffer_init(tty);
2773 mutex_init(&tty->termios_mutex);
2774 init_waitqueue_head(&tty->write_wait);
2775 init_waitqueue_head(&tty->read_wait);
2776 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2777 mutex_init(&tty->atomic_read_lock);
2778 mutex_init(&tty->atomic_write_lock);
2779 mutex_init(&tty->output_lock);
2780 mutex_init(&tty->echo_lock);
2781 spin_lock_init(&tty->read_lock);
2782 spin_lock_init(&tty->ctrl_lock);
2783 INIT_LIST_HEAD(&tty->tty_files);
2784 INIT_WORK(&tty->SAK_work, do_SAK_work);
2786 tty->driver = driver;
2787 tty->ops = driver->ops;
2789 tty_line_name(driver, idx, tty->name);
2793 * tty_put_char - write one character to a tty
2797 * Write one byte to the tty using the provided put_char method
2798 * if present. Returns the number of characters successfully output.
2800 * Note: the specific put_char operation in the driver layer may go
2801 * away soon. Don't call it directly, use this method
2804 int tty_put_char(struct tty_struct *tty, unsigned char ch)
2806 if (tty->ops->put_char)
2807 return tty->ops->put_char(tty, ch);
2808 return tty->ops->write(tty, &ch, 1);
2810 EXPORT_SYMBOL_GPL(tty_put_char);
2812 struct class *tty_class;
2815 * tty_register_device - register a tty device
2816 * @driver: the tty driver that describes the tty device
2817 * @index: the index in the tty driver for this tty device
2818 * @device: a struct device that is associated with this tty device.
2819 * This field is optional, if there is no known struct device
2820 * for this tty device it can be set to NULL safely.
2822 * Returns a pointer to the struct device for this tty device
2823 * (or ERR_PTR(-EFOO) on error).
2825 * This call is required to be made to register an individual tty device
2826 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2827 * that bit is not set, this function should not be called by a tty
2833 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
2834 struct device *device)
2837 dev_t dev = MKDEV(driver->major, driver->minor_start) + index;
2839 if (index >= driver->num) {
2840 printk(KERN_ERR "Attempt to register invalid tty line number "
2842 return ERR_PTR(-EINVAL);
2845 if (driver->type == TTY_DRIVER_TYPE_PTY)
2846 pty_line_name(driver, index, name);
2848 tty_line_name(driver, index, name);
2850 return device_create(tty_class, device, dev, NULL, name);
2852 EXPORT_SYMBOL(tty_register_device);
2855 * tty_unregister_device - unregister a tty device
2856 * @driver: the tty driver that describes the tty device
2857 * @index: the index in the tty driver for this tty device
2859 * If a tty device is registered with a call to tty_register_device() then
2860 * this function must be called when the tty device is gone.
2865 void tty_unregister_device(struct tty_driver *driver, unsigned index)
2867 device_destroy(tty_class,
2868 MKDEV(driver->major, driver->minor_start) + index);
2870 EXPORT_SYMBOL(tty_unregister_device);
2872 struct tty_driver *alloc_tty_driver(int lines)
2874 struct tty_driver *driver;
2876 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
2878 kref_init(&driver->kref);
2879 driver->magic = TTY_DRIVER_MAGIC;
2880 driver->num = lines;
2881 /* later we'll move allocation of tables here */
2885 EXPORT_SYMBOL(alloc_tty_driver);
2887 static void destruct_tty_driver(struct kref *kref)
2889 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
2891 struct ktermios *tp;
2894 if (driver->flags & TTY_DRIVER_INSTALLED) {
2896 * Free the termios and termios_locked structures because
2897 * we don't want to get memory leaks when modular tty
2898 * drivers are removed from the kernel.
2900 for (i = 0; i < driver->num; i++) {
2901 tp = driver->termios[i];
2903 driver->termios[i] = NULL;
2906 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
2907 tty_unregister_device(driver, i);
2910 proc_tty_unregister_driver(driver);
2911 driver->ttys = NULL;
2912 driver->termios = NULL;
2914 cdev_del(&driver->cdev);
2919 void tty_driver_kref_put(struct tty_driver *driver)
2921 kref_put(&driver->kref, destruct_tty_driver);
2923 EXPORT_SYMBOL(tty_driver_kref_put);
2925 void tty_set_operations(struct tty_driver *driver,
2926 const struct tty_operations *op)
2930 EXPORT_SYMBOL(tty_set_operations);
2932 void put_tty_driver(struct tty_driver *d)
2934 tty_driver_kref_put(d);
2936 EXPORT_SYMBOL(put_tty_driver);
2939 * Called by a tty driver to register itself.
2941 int tty_register_driver(struct tty_driver *driver)
2948 if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) {
2949 p = kzalloc(driver->num * 2 * sizeof(void *), GFP_KERNEL);
2954 if (!driver->major) {
2955 error = alloc_chrdev_region(&dev, driver->minor_start,
2956 driver->num, driver->name);
2958 driver->major = MAJOR(dev);
2959 driver->minor_start = MINOR(dev);
2962 dev = MKDEV(driver->major, driver->minor_start);
2963 error = register_chrdev_region(dev, driver->num, driver->name);
2971 driver->ttys = (struct tty_struct **)p;
2972 driver->termios = (struct ktermios **)(p + driver->num);
2974 driver->ttys = NULL;
2975 driver->termios = NULL;
2978 cdev_init(&driver->cdev, &tty_fops);
2979 driver->cdev.owner = driver->owner;
2980 error = cdev_add(&driver->cdev, dev, driver->num);
2982 unregister_chrdev_region(dev, driver->num);
2983 driver->ttys = NULL;
2984 driver->termios = NULL;
2989 mutex_lock(&tty_mutex);
2990 list_add(&driver->tty_drivers, &tty_drivers);
2991 mutex_unlock(&tty_mutex);
2993 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
2994 for (i = 0; i < driver->num; i++)
2995 tty_register_device(driver, i, NULL);
2997 proc_tty_register_driver(driver);
2998 driver->flags |= TTY_DRIVER_INSTALLED;
3002 EXPORT_SYMBOL(tty_register_driver);
3005 * Called by a tty driver to unregister itself.
3007 int tty_unregister_driver(struct tty_driver *driver)
3011 if (driver->refcount)
3014 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3016 mutex_lock(&tty_mutex);
3017 list_del(&driver->tty_drivers);
3018 mutex_unlock(&tty_mutex);
3022 EXPORT_SYMBOL(tty_unregister_driver);
3024 dev_t tty_devnum(struct tty_struct *tty)
3026 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3028 EXPORT_SYMBOL(tty_devnum);
3030 void proc_clear_tty(struct task_struct *p)
3032 unsigned long flags;
3033 struct tty_struct *tty;
3034 spin_lock_irqsave(&p->sighand->siglock, flags);
3035 tty = p->signal->tty;
3036 p->signal->tty = NULL;
3037 spin_unlock_irqrestore(&p->sighand->siglock, flags);
3041 /* Called under the sighand lock */
3043 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3046 unsigned long flags;
3047 /* We should not have a session or pgrp to put here but.... */
3048 spin_lock_irqsave(&tty->ctrl_lock, flags);
3049 put_pid(tty->session);
3051 tty->pgrp = get_pid(task_pgrp(tsk));
3052 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3053 tty->session = get_pid(task_session(tsk));
3054 if (tsk->signal->tty) {
3055 printk(KERN_DEBUG "tty not NULL!!\n");
3056 tty_kref_put(tsk->signal->tty);
3059 put_pid(tsk->signal->tty_old_pgrp);
3060 tsk->signal->tty = tty_kref_get(tty);
3061 tsk->signal->tty_old_pgrp = NULL;
3064 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3066 spin_lock_irq(&tsk->sighand->siglock);
3067 __proc_set_tty(tsk, tty);
3068 spin_unlock_irq(&tsk->sighand->siglock);
3071 struct tty_struct *get_current_tty(void)
3073 struct tty_struct *tty;
3074 unsigned long flags;
3076 spin_lock_irqsave(¤t->sighand->siglock, flags);
3077 tty = tty_kref_get(current->signal->tty);
3078 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
3081 EXPORT_SYMBOL_GPL(get_current_tty);
3083 void tty_default_fops(struct file_operations *fops)
3089 * Initialize the console device. This is called *early*, so
3090 * we can't necessarily depend on lots of kernel help here.
3091 * Just do some early initializations, and do the complex setup
3094 void __init console_init(void)
3098 /* Setup the default TTY line discipline. */
3102 * set up the console device so that later boot sequences can
3103 * inform about problems etc..
3105 call = __con_initcall_start;
3106 while (call < __con_initcall_end) {
3112 static int __init tty_class_init(void)
3114 tty_class = class_create(THIS_MODULE, "tty");
3115 if (IS_ERR(tty_class))
3116 return PTR_ERR(tty_class);
3120 postcore_initcall(tty_class_init);
3122 /* 3/2004 jmc: why do these devices exist? */
3124 static struct cdev tty_cdev, console_cdev;
3127 * Ok, now we can initialize the rest of the tty devices and can count
3128 * on memory allocations, interrupts etc..
3130 static int __init tty_init(void)
3132 cdev_init(&tty_cdev, &tty_fops);
3133 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3134 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3135 panic("Couldn't register /dev/tty driver\n");
3136 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL,
3139 cdev_init(&console_cdev, &console_fops);
3140 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3141 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3142 panic("Couldn't register /dev/console driver\n");
3143 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3147 vty_init(&console_fops);
3151 module_init(tty_init);