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)
319 if (tty_line >= 0 && tty_line <= p->num && p->ops &&
320 p->ops->poll_init && !p->ops->poll_init(p, tty_line, str)) {
321 res = tty_driver_kref_get(p);
326 mutex_unlock(&tty_mutex);
330 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
334 * tty_check_change - check for POSIX terminal changes
337 * If we try to write to, or set the state of, a terminal and we're
338 * not in the foreground, send a SIGTTOU. If the signal is blocked or
339 * ignored, go ahead and perform the operation. (POSIX 7.2)
344 int tty_check_change(struct tty_struct *tty)
349 if (current->signal->tty != tty)
352 spin_lock_irqsave(&tty->ctrl_lock, flags);
355 printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
358 if (task_pgrp(current) == tty->pgrp)
360 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
361 if (is_ignored(SIGTTOU))
363 if (is_current_pgrp_orphaned()) {
367 kill_pgrp(task_pgrp(current), SIGTTOU, 1);
368 set_thread_flag(TIF_SIGPENDING);
373 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
377 EXPORT_SYMBOL(tty_check_change);
379 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
380 size_t count, loff_t *ppos)
385 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
386 size_t count, loff_t *ppos)
391 /* No kernel lock held - none needed ;) */
392 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
394 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
397 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
400 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
403 static long hung_up_tty_compat_ioctl(struct file *file,
404 unsigned int cmd, unsigned long arg)
406 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
409 static const struct file_operations tty_fops = {
414 .unlocked_ioctl = tty_ioctl,
415 .compat_ioctl = tty_compat_ioctl,
417 .release = tty_release,
418 .fasync = tty_fasync,
421 static const struct file_operations console_fops = {
424 .write = redirected_tty_write,
426 .unlocked_ioctl = tty_ioctl,
427 .compat_ioctl = tty_compat_ioctl,
429 .release = tty_release,
430 .fasync = tty_fasync,
433 static const struct file_operations hung_up_tty_fops = {
435 .read = hung_up_tty_read,
436 .write = hung_up_tty_write,
437 .poll = hung_up_tty_poll,
438 .unlocked_ioctl = hung_up_tty_ioctl,
439 .compat_ioctl = hung_up_tty_compat_ioctl,
440 .release = tty_release,
443 static DEFINE_SPINLOCK(redirect_lock);
444 static struct file *redirect;
447 * tty_wakeup - request more data
450 * Internal and external helper for wakeups of tty. This function
451 * informs the line discipline if present that the driver is ready
452 * to receive more output data.
455 void tty_wakeup(struct tty_struct *tty)
457 struct tty_ldisc *ld;
459 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
460 ld = tty_ldisc_ref(tty);
462 if (ld->ops->write_wakeup)
463 ld->ops->write_wakeup(tty);
467 wake_up_interruptible(&tty->write_wait);
470 EXPORT_SYMBOL_GPL(tty_wakeup);
473 * tty_ldisc_flush - flush line discipline queue
476 * Flush the line discipline queue (if any) for this tty. If there
477 * is no line discipline active this is a no-op.
480 void tty_ldisc_flush(struct tty_struct *tty)
482 struct tty_ldisc *ld = tty_ldisc_ref(tty);
484 if (ld->ops->flush_buffer)
485 ld->ops->flush_buffer(tty);
488 tty_buffer_flush(tty);
491 EXPORT_SYMBOL_GPL(tty_ldisc_flush);
494 * tty_reset_termios - reset terminal state
497 * Restore a terminal to the driver default state
500 static void tty_reset_termios(struct tty_struct *tty)
502 mutex_lock(&tty->termios_mutex);
503 *tty->termios = tty->driver->init_termios;
504 tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
505 tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
506 mutex_unlock(&tty->termios_mutex);
510 * do_tty_hangup - actual handler for hangup events
513 * This can be called by the "eventd" kernel thread. That is process
514 * synchronous but doesn't hold any locks, so we need to make sure we
515 * have the appropriate locks for what we're doing.
517 * The hangup event clears any pending redirections onto the hung up
518 * device. It ensures future writes will error and it does the needed
519 * line discipline hangup and signal delivery. The tty object itself
524 * redirect lock for undoing redirection
525 * file list lock for manipulating list of ttys
526 * tty_ldisc_lock from called functions
527 * termios_mutex resetting termios data
528 * tasklist_lock to walk task list for hangup event
529 * ->siglock to protect ->signal/->sighand
531 static void do_tty_hangup(struct work_struct *work)
533 struct tty_struct *tty =
534 container_of(work, struct tty_struct, hangup_work);
535 struct file *cons_filp = NULL;
536 struct file *filp, *f = NULL;
537 struct task_struct *p;
538 struct tty_ldisc *ld;
539 int closecount = 0, n;
546 /* inuse_filps is protected by the single kernel lock */
549 spin_lock(&redirect_lock);
550 if (redirect && redirect->private_data == tty) {
554 spin_unlock(&redirect_lock);
556 check_tty_count(tty, "do_tty_hangup");
558 /* This breaks for file handles being sent over AF_UNIX sockets ? */
559 list_for_each_entry(filp, &tty->tty_files, f_u.fu_list) {
560 if (filp->f_op->write == redirected_tty_write)
562 if (filp->f_op->write != tty_write)
565 tty_fasync(-1, filp, 0); /* can't block */
566 filp->f_op = &hung_up_tty_fops;
570 * FIXME! What are the locking issues here? This may me overdoing
571 * things... This question is especially important now that we've
572 * removed the irqlock.
574 ld = tty_ldisc_ref(tty);
576 /* We may have no line discipline at this point */
577 if (ld->ops->flush_buffer)
578 ld->ops->flush_buffer(tty);
579 tty_driver_flush_buffer(tty);
580 if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) &&
581 ld->ops->write_wakeup)
582 ld->ops->write_wakeup(tty);
584 ld->ops->hangup(tty);
587 * FIXME: Once we trust the LDISC code better we can wait here for
588 * ldisc completion and fix the driver call race
590 wake_up_interruptible(&tty->write_wait);
591 wake_up_interruptible(&tty->read_wait);
593 * Shutdown the current line discipline, and reset it to
596 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
597 tty_reset_termios(tty);
598 /* Defer ldisc switch */
599 /* tty_deferred_ldisc_switch(N_TTY);
601 This should get done automatically when the port closes and
602 tty_release is called */
604 read_lock(&tasklist_lock);
606 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
607 spin_lock_irq(&p->sighand->siglock);
608 if (p->signal->tty == tty) {
609 p->signal->tty = NULL;
610 /* We defer the dereferences outside fo
614 if (!p->signal->leader) {
615 spin_unlock_irq(&p->sighand->siglock);
618 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
619 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
620 put_pid(p->signal->tty_old_pgrp); /* A noop */
621 spin_lock_irqsave(&tty->ctrl_lock, flags);
623 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
624 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
625 spin_unlock_irq(&p->sighand->siglock);
626 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
628 read_unlock(&tasklist_lock);
630 spin_lock_irqsave(&tty->ctrl_lock, flags);
632 put_pid(tty->session);
636 tty->ctrl_status = 0;
637 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
639 /* Account for the p->signal references we killed */
644 * If one of the devices matches a console pointer, we
645 * cannot just call hangup() because that will cause
646 * tty->count and state->count to go out of sync.
647 * So we just call close() the right number of times.
651 for (n = 0; n < closecount; n++)
652 tty->ops->close(tty, cons_filp);
653 } else if (tty->ops->hangup)
654 (tty->ops->hangup)(tty);
656 * We don't want to have driver/ldisc interactions beyond
657 * the ones we did here. The driver layer expects no
658 * calls after ->hangup() from the ldisc side. However we
659 * can't yet guarantee all that.
661 set_bit(TTY_HUPPED, &tty->flags);
663 tty_ldisc_enable(tty);
672 * tty_hangup - trigger a hangup event
673 * @tty: tty to hangup
675 * A carrier loss (virtual or otherwise) has occurred on this like
676 * schedule a hangup sequence to run after this event.
679 void tty_hangup(struct tty_struct *tty)
681 #ifdef TTY_DEBUG_HANGUP
683 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
685 schedule_work(&tty->hangup_work);
688 EXPORT_SYMBOL(tty_hangup);
691 * tty_vhangup - process vhangup
692 * @tty: tty to hangup
694 * The user has asked via system call for the terminal to be hung up.
695 * We do this synchronously so that when the syscall returns the process
696 * is complete. That guarantee is necessary for security reasons.
699 void tty_vhangup(struct tty_struct *tty)
701 #ifdef TTY_DEBUG_HANGUP
704 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
706 do_tty_hangup(&tty->hangup_work);
709 EXPORT_SYMBOL(tty_vhangup);
712 * tty_vhangup_self - process vhangup for own ctty
714 * Perform a vhangup on the current controlling tty
717 void tty_vhangup_self(void)
719 struct tty_struct *tty;
721 tty = get_current_tty();
729 * tty_hung_up_p - was tty hung up
730 * @filp: file pointer of tty
732 * Return true if the tty has been subject to a vhangup or a carrier
736 int tty_hung_up_p(struct file *filp)
738 return (filp->f_op == &hung_up_tty_fops);
741 EXPORT_SYMBOL(tty_hung_up_p);
743 static void session_clear_tty(struct pid *session)
745 struct task_struct *p;
746 do_each_pid_task(session, PIDTYPE_SID, p) {
748 } while_each_pid_task(session, PIDTYPE_SID, p);
752 * disassociate_ctty - disconnect controlling tty
753 * @on_exit: true if exiting so need to "hang up" the session
755 * This function is typically called only by the session leader, when
756 * it wants to disassociate itself from its controlling tty.
758 * It performs the following functions:
759 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
760 * (2) Clears the tty from being controlling the session
761 * (3) Clears the controlling tty for all processes in the
764 * The argument on_exit is set to 1 if called when a process is
765 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
768 * BKL is taken for hysterical raisins
769 * tty_mutex is taken to protect tty
770 * ->siglock is taken to protect ->signal/->sighand
771 * tasklist_lock is taken to walk process list for sessions
772 * ->siglock is taken to protect ->signal/->sighand
775 void disassociate_ctty(int on_exit)
777 struct tty_struct *tty;
778 struct pid *tty_pgrp = NULL;
781 tty = get_current_tty();
783 tty_pgrp = get_pid(tty->pgrp);
785 if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY)
789 } else if (on_exit) {
790 struct pid *old_pgrp;
791 spin_lock_irq(¤t->sighand->siglock);
792 old_pgrp = current->signal->tty_old_pgrp;
793 current->signal->tty_old_pgrp = NULL;
794 spin_unlock_irq(¤t->sighand->siglock);
796 kill_pgrp(old_pgrp, SIGHUP, on_exit);
797 kill_pgrp(old_pgrp, SIGCONT, on_exit);
803 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
805 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
809 spin_lock_irq(¤t->sighand->siglock);
810 put_pid(current->signal->tty_old_pgrp);
811 current->signal->tty_old_pgrp = NULL;
812 spin_unlock_irq(¤t->sighand->siglock);
814 tty = get_current_tty();
817 spin_lock_irqsave(&tty->ctrl_lock, flags);
818 put_pid(tty->session);
822 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
825 #ifdef TTY_DEBUG_HANGUP
826 printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
831 /* Now clear signal->tty under the lock */
832 read_lock(&tasklist_lock);
833 session_clear_tty(task_session(current));
834 read_unlock(&tasklist_lock);
839 * no_tty - Ensure the current process does not have a controlling tty
843 struct task_struct *tsk = current;
845 if (tsk->signal->leader)
846 disassociate_ctty(0);
853 * stop_tty - propagate flow control
856 * Perform flow control to the driver. For PTY/TTY pairs we
857 * must also propagate the TIOCKPKT status. May be called
858 * on an already stopped device and will not re-call the driver
861 * This functionality is used by both the line disciplines for
862 * halting incoming flow and by the driver. It may therefore be
863 * called from any context, may be under the tty atomic_write_lock
867 * Uses the tty control lock internally
870 void stop_tty(struct tty_struct *tty)
873 spin_lock_irqsave(&tty->ctrl_lock, flags);
875 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
879 if (tty->link && tty->link->packet) {
880 tty->ctrl_status &= ~TIOCPKT_START;
881 tty->ctrl_status |= TIOCPKT_STOP;
882 wake_up_interruptible(&tty->link->read_wait);
884 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
886 (tty->ops->stop)(tty);
889 EXPORT_SYMBOL(stop_tty);
892 * start_tty - propagate flow control
895 * Start a tty that has been stopped if at all possible. Perform
896 * any necessary wakeups and propagate the TIOCPKT status. If this
897 * is the tty was previous stopped and is being started then the
898 * driver start method is invoked and the line discipline woken.
904 void start_tty(struct tty_struct *tty)
907 spin_lock_irqsave(&tty->ctrl_lock, flags);
908 if (!tty->stopped || tty->flow_stopped) {
909 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
913 if (tty->link && tty->link->packet) {
914 tty->ctrl_status &= ~TIOCPKT_STOP;
915 tty->ctrl_status |= TIOCPKT_START;
916 wake_up_interruptible(&tty->link->read_wait);
918 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
920 (tty->ops->start)(tty);
921 /* If we have a running line discipline it may need kicking */
925 EXPORT_SYMBOL(start_tty);
928 * tty_read - read method for tty device files
929 * @file: pointer to tty file
931 * @count: size of user buffer
934 * Perform the read system call function on this terminal device. Checks
935 * for hung up devices before calling the line discipline method.
938 * Locks the line discipline internally while needed. Multiple
939 * read calls may be outstanding in parallel.
942 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
946 struct tty_struct *tty;
948 struct tty_ldisc *ld;
950 tty = (struct tty_struct *)file->private_data;
951 inode = file->f_path.dentry->d_inode;
952 if (tty_paranoia_check(tty, inode, "tty_read"))
954 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
957 /* We want to wait for the line discipline to sort out in this
959 ld = tty_ldisc_ref_wait(tty);
961 i = (ld->ops->read)(tty, file, buf, count);
966 inode->i_atime = current_fs_time(inode->i_sb);
970 void tty_write_unlock(struct tty_struct *tty)
972 mutex_unlock(&tty->atomic_write_lock);
973 wake_up_interruptible(&tty->write_wait);
976 int tty_write_lock(struct tty_struct *tty, int ndelay)
978 if (!mutex_trylock(&tty->atomic_write_lock)) {
981 if (mutex_lock_interruptible(&tty->atomic_write_lock))
988 * Split writes up in sane blocksizes to avoid
989 * denial-of-service type attacks
991 static inline ssize_t do_tty_write(
992 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
993 struct tty_struct *tty,
995 const char __user *buf,
998 ssize_t ret, written = 0;
1001 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
1006 * We chunk up writes into a temporary buffer. This
1007 * simplifies low-level drivers immensely, since they
1008 * don't have locking issues and user mode accesses.
1010 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1013 * The default chunk-size is 2kB, because the NTTY
1014 * layer has problems with bigger chunks. It will
1015 * claim to be able to handle more characters than
1018 * FIXME: This can probably go away now except that 64K chunks
1019 * are too likely to fail unless switched to vmalloc...
1022 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1027 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1028 if (tty->write_cnt < chunk) {
1034 buf = kmalloc(chunk, GFP_KERNEL);
1039 kfree(tty->write_buf);
1040 tty->write_cnt = chunk;
1041 tty->write_buf = buf;
1044 /* Do the write .. */
1046 size_t size = count;
1050 if (copy_from_user(tty->write_buf, buf, size))
1052 ret = write(tty, file, tty->write_buf, size);
1061 if (signal_pending(current))
1066 struct inode *inode = file->f_path.dentry->d_inode;
1067 inode->i_mtime = current_fs_time(inode->i_sb);
1071 tty_write_unlock(tty);
1076 * tty_write_message - write a message to a certain tty, not just the console.
1077 * @tty: the destination tty_struct
1078 * @msg: the message to write
1080 * This is used for messages that need to be redirected to a specific tty.
1081 * We don't put it into the syslog queue right now maybe in the future if
1084 * We must still hold the BKL and test the CLOSING flag for the moment.
1087 void tty_write_message(struct tty_struct *tty, char *msg)
1091 mutex_lock(&tty->atomic_write_lock);
1092 if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags))
1093 tty->ops->write(tty, msg, strlen(msg));
1094 tty_write_unlock(tty);
1102 * tty_write - write method for tty device file
1103 * @file: tty file pointer
1104 * @buf: user data to write
1105 * @count: bytes to write
1108 * Write data to a tty device via the line discipline.
1111 * Locks the line discipline as required
1112 * Writes to the tty driver are serialized by the atomic_write_lock
1113 * and are then processed in chunks to the device. The line discipline
1114 * write method will not be involked in parallel for each device
1115 * The line discipline write method is called under the big
1116 * kernel lock for historical reasons. New code should not rely on this.
1119 static ssize_t tty_write(struct file *file, const char __user *buf,
1120 size_t count, loff_t *ppos)
1122 struct tty_struct *tty;
1123 struct inode *inode = file->f_path.dentry->d_inode;
1125 struct tty_ldisc *ld;
1127 tty = (struct tty_struct *)file->private_data;
1128 if (tty_paranoia_check(tty, inode, "tty_write"))
1130 if (!tty || !tty->ops->write ||
1131 (test_bit(TTY_IO_ERROR, &tty->flags)))
1133 /* Short term debug to catch buggy drivers */
1134 if (tty->ops->write_room == NULL)
1135 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1137 ld = tty_ldisc_ref_wait(tty);
1138 if (!ld->ops->write)
1141 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1142 tty_ldisc_deref(ld);
1146 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1147 size_t count, loff_t *ppos)
1149 struct file *p = NULL;
1151 spin_lock(&redirect_lock);
1156 spin_unlock(&redirect_lock);
1160 res = vfs_write(p, buf, count, &p->f_pos);
1164 return tty_write(file, buf, count, ppos);
1167 static char ptychar[] = "pqrstuvwxyzabcde";
1170 * pty_line_name - generate name for a pty
1171 * @driver: the tty driver in use
1172 * @index: the minor number
1173 * @p: output buffer of at least 6 bytes
1175 * Generate a name from a driver reference and write it to the output
1180 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1182 int i = index + driver->name_base;
1183 /* ->name is initialized to "ttyp", but "tty" is expected */
1184 sprintf(p, "%s%c%x",
1185 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1186 ptychar[i >> 4 & 0xf], i & 0xf);
1190 * tty_line_name - generate name for a tty
1191 * @driver: the tty driver in use
1192 * @index: the minor number
1193 * @p: output buffer of at least 7 bytes
1195 * Generate a name from a driver reference and write it to the output
1200 static void tty_line_name(struct tty_driver *driver, int index, char *p)
1202 sprintf(p, "%s%d", driver->name, index + driver->name_base);
1206 * tty_driver_lookup_tty() - find an existing tty, if any
1207 * @driver: the driver for the tty
1208 * @idx: the minor number
1210 * Return the tty, if found or ERR_PTR() otherwise.
1212 * Locking: tty_mutex must be held. If tty is found, the mutex must
1213 * be held until the 'fast-open' is also done. Will change once we
1214 * have refcounting in the driver and per driver locking
1216 struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1217 struct inode *inode, int idx)
1219 struct tty_struct *tty;
1221 if (driver->ops->lookup)
1222 return driver->ops->lookup(driver, inode, idx);
1224 tty = driver->ttys[idx];
1229 * tty_init_termios - helper for termios setup
1230 * @tty: the tty to set up
1232 * Initialise the termios structures for this tty. Thus runs under
1233 * the tty_mutex currently so we can be relaxed about ordering.
1236 int tty_init_termios(struct tty_struct *tty)
1238 struct ktermios *tp, *ltp;
1239 int idx = tty->index;
1241 tp = tty->driver->termios[idx];
1242 ltp = tty->driver->termios_locked[idx];
1244 WARN_ON(ltp != NULL);
1245 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1246 ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL);
1247 if (tp == NULL || ltp == NULL) {
1252 memcpy(tp, &tty->driver->init_termios,
1253 sizeof(struct ktermios));
1254 tty->driver->termios[idx] = tp;
1255 tty->driver->termios_locked[idx] = ltp;
1258 tty->termios_locked = ltp;
1260 /* Compatibility until drivers always set this */
1261 tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
1262 tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
1267 * tty_driver_install_tty() - install a tty entry in the driver
1268 * @driver: the driver for the tty
1271 * Install a tty object into the driver tables. The tty->index field
1272 * will be set by the time this is called. This method is responsible
1273 * for ensuring any need additional structures are allocated and
1276 * Locking: tty_mutex for now
1278 static int tty_driver_install_tty(struct tty_driver *driver,
1279 struct tty_struct *tty)
1281 int idx = tty->index;
1283 if (driver->ops->install)
1284 return driver->ops->install(driver, tty);
1286 if (tty_init_termios(tty) == 0) {
1287 tty_driver_kref_get(driver);
1289 driver->ttys[idx] = tty;
1296 * tty_driver_remove_tty() - remove a tty from the driver tables
1297 * @driver: the driver for the tty
1298 * @idx: the minor number
1300 * Remvoe a tty object from the driver tables. The tty->index field
1301 * will be set by the time this is called.
1303 * Locking: tty_mutex for now
1305 static void tty_driver_remove_tty(struct tty_driver *driver,
1306 struct tty_struct *tty)
1308 if (driver->ops->remove)
1309 driver->ops->remove(driver, tty);
1311 driver->ttys[tty->index] = NULL;
1315 * tty_reopen() - fast re-open of an open tty
1316 * @tty - the tty to open
1318 * Return 0 on success, -errno on error.
1320 * Locking: tty_mutex must be held from the time the tty was found
1321 * till this open completes.
1323 static int tty_reopen(struct tty_struct *tty)
1325 struct tty_driver *driver = tty->driver;
1327 if (test_bit(TTY_CLOSING, &tty->flags))
1330 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1331 driver->subtype == PTY_TYPE_MASTER) {
1333 * special case for PTY masters: only one open permitted,
1334 * and the slave side open count is incremented as well.
1342 tty->driver = driver; /* N.B. why do this every time?? */
1344 WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
1350 * tty_init_dev - initialise a tty device
1351 * @driver: tty driver we are opening a device on
1352 * @idx: device index
1353 * @ret_tty: returned tty structure
1354 * @first_ok: ok to open a new device (used by ptmx)
1356 * Prepare a tty device. This may not be a "new" clean device but
1357 * could also be an active device. The pty drivers require special
1358 * handling because of this.
1361 * The function is called under the tty_mutex, which
1362 * protects us from the tty struct or driver itself going away.
1364 * On exit the tty device has the line discipline attached and
1365 * a reference count of 1. If a pair was created for pty/tty use
1366 * and the other was a pty master then it too has a reference count of 1.
1368 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1369 * failed open. The new code protects the open with a mutex, so it's
1370 * really quite straightforward. The mutex locking can probably be
1371 * relaxed for the (most common) case of reopening a tty.
1374 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx,
1377 struct tty_struct *tty;
1380 /* Check if pty master is being opened multiple times */
1381 if (driver->subtype == PTY_TYPE_MASTER &&
1382 (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok)
1383 return ERR_PTR(-EIO);
1386 * First time open is complex, especially for PTY devices.
1387 * This code guarantees that either everything succeeds and the
1388 * TTY is ready for operation, or else the table slots are vacated
1389 * and the allocated memory released. (Except that the termios
1390 * and locked termios may be retained.)
1393 if (!try_module_get(driver->owner))
1394 return ERR_PTR(-ENODEV);
1396 tty = alloc_tty_struct();
1399 initialize_tty_struct(tty, driver, idx);
1401 retval = tty_driver_install_tty(driver, tty);
1403 free_tty_struct(tty);
1404 module_put(driver->owner);
1405 return ERR_PTR(retval);
1409 * Structures all installed ... call the ldisc open routines.
1410 * If we fail here just call release_tty to clean up. No need
1411 * to decrement the use counts, as release_tty doesn't care.
1414 retval = tty_ldisc_setup(tty, tty->link);
1416 goto release_mem_out;
1420 module_put(driver->owner);
1421 return ERR_PTR(-ENOMEM);
1423 /* call the tty release_tty routine to clean out this slot */
1425 if (printk_ratelimit())
1426 printk(KERN_INFO "tty_init_dev: ldisc open failed, "
1427 "clearing slot %d\n", idx);
1428 release_tty(tty, idx);
1429 return ERR_PTR(retval);
1432 void tty_free_termios(struct tty_struct *tty)
1434 struct ktermios *tp;
1435 int idx = tty->index;
1436 /* Kill this flag and push into drivers for locking etc */
1437 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
1438 /* FIXME: Locking on ->termios array */
1440 tty->driver->termios[idx] = NULL;
1443 tp = tty->termios_locked;
1444 tty->driver->termios_locked[idx] = NULL;
1448 EXPORT_SYMBOL(tty_free_termios);
1450 void tty_shutdown(struct tty_struct *tty)
1452 tty_driver_remove_tty(tty->driver, tty);
1453 tty_free_termios(tty);
1455 EXPORT_SYMBOL(tty_shutdown);
1458 * release_one_tty - release tty structure memory
1459 * @kref: kref of tty we are obliterating
1461 * Releases memory associated with a tty structure, and clears out the
1462 * driver table slots. This function is called when a device is no longer
1463 * in use. It also gets called when setup of a device fails.
1466 * tty_mutex - sometimes only
1467 * takes the file list lock internally when working on the list
1468 * of ttys that the driver keeps.
1470 static void release_one_tty(struct kref *kref)
1472 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1473 struct tty_driver *driver = tty->driver;
1475 if (tty->ops->shutdown)
1476 tty->ops->shutdown(tty);
1480 tty_driver_kref_put(driver);
1481 module_put(driver->owner);
1484 list_del_init(&tty->tty_files);
1487 free_tty_struct(tty);
1491 * tty_kref_put - release a tty kref
1494 * Release a reference to a tty device and if need be let the kref
1495 * layer destruct the object for us
1498 void tty_kref_put(struct tty_struct *tty)
1501 kref_put(&tty->kref, release_one_tty);
1503 EXPORT_SYMBOL(tty_kref_put);
1506 * release_tty - release tty structure memory
1508 * Release both @tty and a possible linked partner (think pty pair),
1509 * and decrement the refcount of the backing module.
1512 * tty_mutex - sometimes only
1513 * takes the file list lock internally when working on the list
1514 * of ttys that the driver keeps.
1515 * FIXME: should we require tty_mutex is held here ??
1518 static void release_tty(struct tty_struct *tty, int idx)
1520 /* This should always be true but check for the moment */
1521 WARN_ON(tty->index != idx);
1524 tty_kref_put(tty->link);
1529 * Even releasing the tty structures is a tricky business.. We have
1530 * to be very careful that the structures are all released at the
1531 * same time, as interrupts might otherwise get the wrong pointers.
1533 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1534 * lead to double frees or releasing memory still in use.
1536 void tty_release_dev(struct file *filp)
1538 struct tty_struct *tty, *o_tty;
1539 int pty_master, tty_closing, o_tty_closing, do_sleep;
1543 struct inode *inode;
1545 inode = filp->f_path.dentry->d_inode;
1546 tty = (struct tty_struct *)filp->private_data;
1547 if (tty_paranoia_check(tty, inode, "tty_release_dev"))
1550 check_tty_count(tty, "tty_release_dev");
1552 tty_fasync(-1, filp, 0);
1555 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1556 tty->driver->subtype == PTY_TYPE_MASTER);
1557 devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
1560 #ifdef TTY_PARANOIA_CHECK
1561 if (idx < 0 || idx >= tty->driver->num) {
1562 printk(KERN_DEBUG "tty_release_dev: bad idx when trying to "
1563 "free (%s)\n", tty->name);
1567 if (tty != tty->driver->ttys[idx]) {
1568 printk(KERN_DEBUG "tty_release_dev: driver.table[%d] not tty "
1569 "for (%s)\n", idx, tty->name);
1572 if (tty->termios != tty->driver->termios[idx]) {
1573 printk(KERN_DEBUG "tty_release_dev: driver.termios[%d] not termios "
1578 if (tty->termios_locked != tty->driver->termios_locked[idx]) {
1579 printk(KERN_DEBUG "tty_release_dev: driver.termios_locked[%d] not "
1580 "termios_locked for (%s)\n",
1587 #ifdef TTY_DEBUG_HANGUP
1588 printk(KERN_DEBUG "tty_release_dev of %s (tty count=%d)...",
1589 tty_name(tty, buf), tty->count);
1592 #ifdef TTY_PARANOIA_CHECK
1593 if (tty->driver->other &&
1594 !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
1595 if (o_tty != tty->driver->other->ttys[idx]) {
1596 printk(KERN_DEBUG "tty_release_dev: other->table[%d] "
1597 "not o_tty for (%s)\n",
1601 if (o_tty->termios != tty->driver->other->termios[idx]) {
1602 printk(KERN_DEBUG "tty_release_dev: other->termios[%d] "
1603 "not o_termios for (%s)\n",
1607 if (o_tty->termios_locked !=
1608 tty->driver->other->termios_locked[idx]) {
1609 printk(KERN_DEBUG "tty_release_dev: other->termios_locked["
1610 "%d] not o_termios_locked for (%s)\n",
1614 if (o_tty->link != tty) {
1615 printk(KERN_DEBUG "tty_release_dev: bad pty pointers\n");
1620 if (tty->ops->close)
1621 tty->ops->close(tty, filp);
1624 * Sanity check: if tty->count is going to zero, there shouldn't be
1625 * any waiters on tty->read_wait or tty->write_wait. We test the
1626 * wait queues and kick everyone out _before_ actually starting to
1627 * close. This ensures that we won't block while releasing the tty
1630 * The test for the o_tty closing is necessary, since the master and
1631 * slave sides may close in any order. If the slave side closes out
1632 * first, its count will be one, since the master side holds an open.
1633 * Thus this test wouldn't be triggered at the time the slave closes,
1636 * Note that it's possible for the tty to be opened again while we're
1637 * flushing out waiters. By recalculating the closing flags before
1638 * each iteration we avoid any problems.
1641 /* Guard against races with tty->count changes elsewhere and
1642 opens on /dev/tty */
1644 mutex_lock(&tty_mutex);
1645 tty_closing = tty->count <= 1;
1646 o_tty_closing = o_tty &&
1647 (o_tty->count <= (pty_master ? 1 : 0));
1651 if (waitqueue_active(&tty->read_wait)) {
1652 wake_up(&tty->read_wait);
1655 if (waitqueue_active(&tty->write_wait)) {
1656 wake_up(&tty->write_wait);
1660 if (o_tty_closing) {
1661 if (waitqueue_active(&o_tty->read_wait)) {
1662 wake_up(&o_tty->read_wait);
1665 if (waitqueue_active(&o_tty->write_wait)) {
1666 wake_up(&o_tty->write_wait);
1673 printk(KERN_WARNING "tty_release_dev: %s: read/write wait queue "
1674 "active!\n", tty_name(tty, buf));
1675 mutex_unlock(&tty_mutex);
1680 * The closing flags are now consistent with the open counts on
1681 * both sides, and we've completed the last operation that could
1682 * block, so it's safe to proceed with closing.
1685 if (--o_tty->count < 0) {
1686 printk(KERN_WARNING "tty_release_dev: bad pty slave count "
1688 o_tty->count, tty_name(o_tty, buf));
1692 if (--tty->count < 0) {
1693 printk(KERN_WARNING "tty_release_dev: bad tty->count (%d) for %s\n",
1694 tty->count, tty_name(tty, buf));
1699 * We've decremented tty->count, so we need to remove this file
1700 * descriptor off the tty->tty_files list; this serves two
1702 * - check_tty_count sees the correct number of file descriptors
1703 * associated with this tty.
1704 * - do_tty_hangup no longer sees this file descriptor as
1705 * something that needs to be handled for hangups.
1708 filp->private_data = NULL;
1711 * Perform some housekeeping before deciding whether to return.
1713 * Set the TTY_CLOSING flag if this was the last open. In the
1714 * case of a pty we may have to wait around for the other side
1715 * to close, and TTY_CLOSING makes sure we can't be reopened.
1718 set_bit(TTY_CLOSING, &tty->flags);
1720 set_bit(TTY_CLOSING, &o_tty->flags);
1723 * If _either_ side is closing, make sure there aren't any
1724 * processes that still think tty or o_tty is their controlling
1727 if (tty_closing || o_tty_closing) {
1728 read_lock(&tasklist_lock);
1729 session_clear_tty(tty->session);
1731 session_clear_tty(o_tty->session);
1732 read_unlock(&tasklist_lock);
1735 mutex_unlock(&tty_mutex);
1737 /* check whether both sides are closing ... */
1738 if (!tty_closing || (o_tty && !o_tty_closing))
1741 #ifdef TTY_DEBUG_HANGUP
1742 printk(KERN_DEBUG "freeing tty structure...");
1745 * Ask the line discipline code to release its structures
1747 tty_ldisc_release(tty, o_tty);
1749 * The release_tty function takes care of the details of clearing
1750 * the slots and preserving the termios structure.
1752 release_tty(tty, idx);
1754 /* Make this pty number available for reallocation */
1756 devpts_kill_index(inode, idx);
1760 * __tty_open - open a tty device
1761 * @inode: inode of device file
1762 * @filp: file pointer to tty
1764 * tty_open and tty_release keep up the tty count that contains the
1765 * number of opens done on a tty. We cannot use the inode-count, as
1766 * different inodes might point to the same tty.
1768 * Open-counting is needed for pty masters, as well as for keeping
1769 * track of serial lines: DTR is dropped when the last close happens.
1770 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1772 * The termios state of a pty is reset on first open so that
1773 * settings don't persist across reuse.
1775 * Locking: tty_mutex protects tty, get_tty_driver and tty_init_dev work.
1776 * tty->count should protect the rest.
1777 * ->siglock protects ->signal/->sighand
1780 static int __tty_open(struct inode *inode, struct file *filp)
1782 struct tty_struct *tty = NULL;
1784 struct tty_driver *driver;
1786 dev_t device = inode->i_rdev;
1787 unsigned short saved_flags = filp->f_flags;
1789 nonseekable_open(inode, filp);
1792 noctty = filp->f_flags & O_NOCTTY;
1796 mutex_lock(&tty_mutex);
1798 if (device == MKDEV(TTYAUX_MAJOR, 0)) {
1799 tty = get_current_tty();
1801 mutex_unlock(&tty_mutex);
1804 driver = tty_driver_kref_get(tty->driver);
1806 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1808 /* FIXME: Should we take a driver reference ? */
1813 if (device == MKDEV(TTY_MAJOR, 0)) {
1814 extern struct tty_driver *console_driver;
1815 driver = tty_driver_kref_get(console_driver);
1821 if (device == MKDEV(TTYAUX_MAJOR, 1)) {
1822 driver = tty_driver_kref_get(console_device(&index));
1824 /* Don't let /dev/console block */
1825 filp->f_flags |= O_NONBLOCK;
1829 mutex_unlock(&tty_mutex);
1833 driver = get_tty_driver(device, &index);
1835 mutex_unlock(&tty_mutex);
1840 /* check whether we're reopening an existing tty */
1841 tty = tty_driver_lookup_tty(driver, inode, index);
1844 return PTR_ERR(tty);
1848 retval = tty_reopen(tty);
1850 tty = ERR_PTR(retval);
1852 tty = tty_init_dev(driver, index, 0);
1854 mutex_unlock(&tty_mutex);
1855 tty_driver_kref_put(driver);
1857 return PTR_ERR(tty);
1859 filp->private_data = tty;
1860 file_move(filp, &tty->tty_files);
1861 check_tty_count(tty, "tty_open");
1862 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1863 tty->driver->subtype == PTY_TYPE_MASTER)
1865 #ifdef TTY_DEBUG_HANGUP
1866 printk(KERN_DEBUG "opening %s...", tty->name);
1870 retval = tty->ops->open(tty, filp);
1874 filp->f_flags = saved_flags;
1876 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
1877 !capable(CAP_SYS_ADMIN))
1881 #ifdef TTY_DEBUG_HANGUP
1882 printk(KERN_DEBUG "error %d in opening %s...", retval,
1885 tty_release_dev(filp);
1886 if (retval != -ERESTARTSYS)
1888 if (signal_pending(current))
1892 * Need to reset f_op in case a hangup happened.
1894 if (filp->f_op == &hung_up_tty_fops)
1895 filp->f_op = &tty_fops;
1899 mutex_lock(&tty_mutex);
1900 spin_lock_irq(¤t->sighand->siglock);
1902 current->signal->leader &&
1903 !current->signal->tty &&
1904 tty->session == NULL)
1905 __proc_set_tty(current, tty);
1906 spin_unlock_irq(¤t->sighand->siglock);
1907 mutex_unlock(&tty_mutex);
1911 /* BKL pushdown: scary code avoidance wrapper */
1912 static int tty_open(struct inode *inode, struct file *filp)
1917 ret = __tty_open(inode, filp);
1926 * tty_release - vfs callback for close
1927 * @inode: inode of tty
1928 * @filp: file pointer for handle to tty
1930 * Called the last time each file handle is closed that references
1931 * this tty. There may however be several such references.
1934 * Takes bkl. See tty_release_dev
1937 static int tty_release(struct inode *inode, struct file *filp)
1940 tty_release_dev(filp);
1946 * tty_poll - check tty status
1947 * @filp: file being polled
1948 * @wait: poll wait structures to update
1950 * Call the line discipline polling method to obtain the poll
1951 * status of the device.
1953 * Locking: locks called line discipline but ldisc poll method
1954 * may be re-entered freely by other callers.
1957 static unsigned int tty_poll(struct file *filp, poll_table *wait)
1959 struct tty_struct *tty;
1960 struct tty_ldisc *ld;
1963 tty = (struct tty_struct *)filp->private_data;
1964 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll"))
1967 ld = tty_ldisc_ref_wait(tty);
1969 ret = (ld->ops->poll)(tty, filp, wait);
1970 tty_ldisc_deref(ld);
1974 static int tty_fasync(int fd, struct file *filp, int on)
1976 struct tty_struct *tty;
1977 unsigned long flags;
1981 tty = (struct tty_struct *)filp->private_data;
1982 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
1985 retval = fasync_helper(fd, filp, on, &tty->fasync);
1992 if (!waitqueue_active(&tty->read_wait))
1993 tty->minimum_to_wake = 1;
1994 spin_lock_irqsave(&tty->ctrl_lock, flags);
1997 type = PIDTYPE_PGID;
1999 pid = task_pid(current);
2002 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2003 retval = __f_setown(filp, pid, type, 0);
2007 if (!tty->fasync && !waitqueue_active(&tty->read_wait))
2008 tty->minimum_to_wake = N_TTY_BUF_SIZE;
2017 * tiocsti - fake input character
2018 * @tty: tty to fake input into
2019 * @p: pointer to character
2021 * Fake input to a tty device. Does the necessary locking and
2024 * FIXME: does not honour flow control ??
2027 * Called functions take tty_ldisc_lock
2028 * current->signal->tty check is safe without locks
2030 * FIXME: may race normal receive processing
2033 static int tiocsti(struct tty_struct *tty, char __user *p)
2036 struct tty_ldisc *ld;
2038 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2040 if (get_user(ch, p))
2042 ld = tty_ldisc_ref_wait(tty);
2043 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2044 tty_ldisc_deref(ld);
2049 * tiocgwinsz - implement window query ioctl
2051 * @arg: user buffer for result
2053 * Copies the kernel idea of the window size into the user buffer.
2055 * Locking: tty->termios_mutex is taken to ensure the winsize data
2059 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2063 mutex_lock(&tty->termios_mutex);
2064 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2065 mutex_unlock(&tty->termios_mutex);
2067 return err ? -EFAULT: 0;
2071 * tty_do_resize - resize event
2072 * @tty: tty being resized
2073 * @real_tty: real tty (not the same as tty if using a pty/tty pair)
2074 * @rows: rows (character)
2075 * @cols: cols (character)
2077 * Update the termios variables and send the neccessary signals to
2078 * peform a terminal resize correctly
2081 int tty_do_resize(struct tty_struct *tty, struct tty_struct *real_tty,
2084 struct pid *pgrp, *rpgrp;
2085 unsigned long flags;
2087 /* For a PTY we need to lock the tty side */
2088 mutex_lock(&real_tty->termios_mutex);
2089 if (!memcmp(ws, &real_tty->winsize, sizeof(*ws)))
2091 /* Get the PID values and reference them so we can
2092 avoid holding the tty ctrl lock while sending signals */
2093 spin_lock_irqsave(&tty->ctrl_lock, flags);
2094 pgrp = get_pid(tty->pgrp);
2095 rpgrp = get_pid(real_tty->pgrp);
2096 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2099 kill_pgrp(pgrp, SIGWINCH, 1);
2100 if (rpgrp != pgrp && rpgrp)
2101 kill_pgrp(rpgrp, SIGWINCH, 1);
2107 real_tty->winsize = *ws;
2109 mutex_unlock(&real_tty->termios_mutex);
2114 * tiocswinsz - implement window size set ioctl
2116 * @arg: user buffer for result
2118 * Copies the user idea of the window size to the kernel. Traditionally
2119 * this is just advisory information but for the Linux console it
2120 * actually has driver level meaning and triggers a VC resize.
2123 * Driver dependant. The default do_resize method takes the
2124 * tty termios mutex and ctrl_lock. The console takes its own lock
2125 * then calls into the default method.
2128 static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty,
2129 struct winsize __user *arg)
2131 struct winsize tmp_ws;
2132 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2135 if (tty->ops->resize)
2136 return tty->ops->resize(tty, real_tty, &tmp_ws);
2138 return tty_do_resize(tty, real_tty, &tmp_ws);
2142 * tioccons - allow admin to move logical console
2143 * @file: the file to become console
2145 * Allow the adminstrator to move the redirected console device
2147 * Locking: uses redirect_lock to guard the redirect information
2150 static int tioccons(struct file *file)
2152 if (!capable(CAP_SYS_ADMIN))
2154 if (file->f_op->write == redirected_tty_write) {
2156 spin_lock(&redirect_lock);
2159 spin_unlock(&redirect_lock);
2164 spin_lock(&redirect_lock);
2166 spin_unlock(&redirect_lock);
2171 spin_unlock(&redirect_lock);
2176 * fionbio - non blocking ioctl
2177 * @file: file to set blocking value
2178 * @p: user parameter
2180 * Historical tty interfaces had a blocking control ioctl before
2181 * the generic functionality existed. This piece of history is preserved
2182 * in the expected tty API of posix OS's.
2184 * Locking: none, the open fle handle ensures it won't go away.
2187 static int fionbio(struct file *file, int __user *p)
2191 if (get_user(nonblock, p))
2194 /* file->f_flags is still BKL protected in the fs layer - vomit */
2197 file->f_flags |= O_NONBLOCK;
2199 file->f_flags &= ~O_NONBLOCK;
2205 * tiocsctty - set controlling tty
2206 * @tty: tty structure
2207 * @arg: user argument
2209 * This ioctl is used to manage job control. It permits a session
2210 * leader to set this tty as the controlling tty for the session.
2213 * Takes tty_mutex() to protect tty instance
2214 * Takes tasklist_lock internally to walk sessions
2215 * Takes ->siglock() when updating signal->tty
2218 static int tiocsctty(struct tty_struct *tty, int arg)
2221 if (current->signal->leader && (task_session(current) == tty->session))
2224 mutex_lock(&tty_mutex);
2226 * The process must be a session leader and
2227 * not have a controlling tty already.
2229 if (!current->signal->leader || current->signal->tty) {
2236 * This tty is already the controlling
2237 * tty for another session group!
2239 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2243 read_lock(&tasklist_lock);
2244 session_clear_tty(tty->session);
2245 read_unlock(&tasklist_lock);
2251 proc_set_tty(current, tty);
2253 mutex_unlock(&tty_mutex);
2258 * tty_get_pgrp - return a ref counted pgrp pid
2261 * Returns a refcounted instance of the pid struct for the process
2262 * group controlling the tty.
2265 struct pid *tty_get_pgrp(struct tty_struct *tty)
2267 unsigned long flags;
2270 spin_lock_irqsave(&tty->ctrl_lock, flags);
2271 pgrp = get_pid(tty->pgrp);
2272 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2276 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2279 * tiocgpgrp - get process group
2280 * @tty: tty passed by user
2281 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2284 * Obtain the process group of the tty. If there is no process group
2287 * Locking: none. Reference to current->signal->tty is safe.
2290 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2295 * (tty == real_tty) is a cheap way of
2296 * testing if the tty is NOT a master pty.
2298 if (tty == real_tty && current->signal->tty != real_tty)
2300 pid = tty_get_pgrp(real_tty);
2301 ret = put_user(pid_vnr(pid), p);
2307 * tiocspgrp - attempt to set process group
2308 * @tty: tty passed by user
2309 * @real_tty: tty side device matching tty passed by user
2312 * Set the process group of the tty to the session passed. Only
2313 * permitted where the tty session is our session.
2315 * Locking: RCU, ctrl lock
2318 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2322 int retval = tty_check_change(real_tty);
2323 unsigned long flags;
2329 if (!current->signal->tty ||
2330 (current->signal->tty != real_tty) ||
2331 (real_tty->session != task_session(current)))
2333 if (get_user(pgrp_nr, p))
2338 pgrp = find_vpid(pgrp_nr);
2343 if (session_of_pgrp(pgrp) != task_session(current))
2346 spin_lock_irqsave(&tty->ctrl_lock, flags);
2347 put_pid(real_tty->pgrp);
2348 real_tty->pgrp = get_pid(pgrp);
2349 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2356 * tiocgsid - get session id
2357 * @tty: tty passed by user
2358 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2359 * @p: pointer to returned session id
2361 * Obtain the session id of the tty. If there is no session
2364 * Locking: none. Reference to current->signal->tty is safe.
2367 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2370 * (tty == real_tty) is a cheap way of
2371 * testing if the tty is NOT a master pty.
2373 if (tty == real_tty && current->signal->tty != real_tty)
2375 if (!real_tty->session)
2377 return put_user(pid_vnr(real_tty->session), p);
2381 * tiocsetd - set line discipline
2383 * @p: pointer to user data
2385 * Set the line discipline according to user request.
2387 * Locking: see tty_set_ldisc, this function is just a helper
2390 static int tiocsetd(struct tty_struct *tty, int __user *p)
2395 if (get_user(ldisc, p))
2399 ret = tty_set_ldisc(tty, ldisc);
2406 * send_break - performed time break
2407 * @tty: device to break on
2408 * @duration: timeout in mS
2410 * Perform a timed break on hardware that lacks its own driver level
2411 * timed break functionality.
2414 * atomic_write_lock serializes
2418 static int send_break(struct tty_struct *tty, unsigned int duration)
2422 if (tty->ops->break_ctl == NULL)
2425 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2426 retval = tty->ops->break_ctl(tty, duration);
2428 /* Do the work ourselves */
2429 if (tty_write_lock(tty, 0) < 0)
2431 retval = tty->ops->break_ctl(tty, -1);
2434 if (!signal_pending(current))
2435 msleep_interruptible(duration);
2436 retval = tty->ops->break_ctl(tty, 0);
2438 tty_write_unlock(tty);
2439 if (signal_pending(current))
2446 * tty_tiocmget - get modem status
2448 * @file: user file pointer
2449 * @p: pointer to result
2451 * Obtain the modem status bits from the tty driver if the feature
2452 * is supported. Return -EINVAL if it is not available.
2454 * Locking: none (up to the driver)
2457 static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p)
2459 int retval = -EINVAL;
2461 if (tty->ops->tiocmget) {
2462 retval = tty->ops->tiocmget(tty, file);
2465 retval = put_user(retval, p);
2471 * tty_tiocmset - set modem status
2473 * @file: user file pointer
2474 * @cmd: command - clear bits, set bits or set all
2475 * @p: pointer to desired bits
2477 * Set the modem status bits from the tty driver if the feature
2478 * is supported. Return -EINVAL if it is not available.
2480 * Locking: none (up to the driver)
2483 static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int cmd,
2487 unsigned int set, clear, val;
2489 if (tty->ops->tiocmset == NULL)
2492 retval = get_user(val, p);
2508 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2509 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2510 return tty->ops->tiocmset(tty, file, set, clear);
2514 * Split this up, as gcc can choke on it otherwise..
2516 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2518 struct tty_struct *tty, *real_tty;
2519 void __user *p = (void __user *)arg;
2521 struct tty_ldisc *ld;
2522 struct inode *inode = file->f_dentry->d_inode;
2524 tty = (struct tty_struct *)file->private_data;
2525 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2529 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2530 tty->driver->subtype == PTY_TYPE_MASTER)
2531 real_tty = tty->link;
2535 * Factor out some common prep work
2543 retval = tty_check_change(tty);
2546 if (cmd != TIOCCBRK) {
2547 tty_wait_until_sent(tty, 0);
2548 if (signal_pending(current))
2559 return tiocsti(tty, p);
2561 return tiocgwinsz(real_tty, p);
2563 return tiocswinsz(tty, real_tty, p);
2565 return real_tty != tty ? -EINVAL : tioccons(file);
2567 return fionbio(file, p);
2569 set_bit(TTY_EXCLUSIVE, &tty->flags);
2572 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2575 if (current->signal->tty != tty)
2580 return tiocsctty(tty, arg);
2582 return tiocgpgrp(tty, real_tty, p);
2584 return tiocspgrp(tty, real_tty, p);
2586 return tiocgsid(tty, real_tty, p);
2588 return put_user(tty->ldisc.ops->num, (int __user *)p);
2590 return tiocsetd(tty, p);
2594 case TIOCSBRK: /* Turn break on, unconditionally */
2595 if (tty->ops->break_ctl)
2596 return tty->ops->break_ctl(tty, -1);
2598 case TIOCCBRK: /* Turn break off, unconditionally */
2599 if (tty->ops->break_ctl)
2600 return tty->ops->break_ctl(tty, 0);
2602 case TCSBRK: /* SVID version: non-zero arg --> no break */
2603 /* non-zero arg means wait for all output data
2604 * to be sent (performed above) but don't send break.
2605 * This is used by the tcdrain() termios function.
2608 return send_break(tty, 250);
2610 case TCSBRKP: /* support for POSIX tcsendbreak() */
2611 return send_break(tty, arg ? arg*100 : 250);
2614 return tty_tiocmget(tty, file, p);
2618 return tty_tiocmset(tty, file, cmd, p);
2623 /* flush tty buffer and allow ldisc to process ioctl */
2624 tty_buffer_flush(tty);
2629 if (tty->ops->ioctl) {
2630 retval = (tty->ops->ioctl)(tty, file, cmd, arg);
2631 if (retval != -ENOIOCTLCMD)
2634 ld = tty_ldisc_ref_wait(tty);
2636 if (ld->ops->ioctl) {
2637 retval = ld->ops->ioctl(tty, file, cmd, arg);
2638 if (retval == -ENOIOCTLCMD)
2641 tty_ldisc_deref(ld);
2645 #ifdef CONFIG_COMPAT
2646 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2649 struct inode *inode = file->f_dentry->d_inode;
2650 struct tty_struct *tty = file->private_data;
2651 struct tty_ldisc *ld;
2652 int retval = -ENOIOCTLCMD;
2654 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2657 if (tty->ops->compat_ioctl) {
2658 retval = (tty->ops->compat_ioctl)(tty, file, cmd, arg);
2659 if (retval != -ENOIOCTLCMD)
2663 ld = tty_ldisc_ref_wait(tty);
2664 if (ld->ops->compat_ioctl)
2665 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2666 tty_ldisc_deref(ld);
2673 * This implements the "Secure Attention Key" --- the idea is to
2674 * prevent trojan horses by killing all processes associated with this
2675 * tty when the user hits the "Secure Attention Key". Required for
2676 * super-paranoid applications --- see the Orange Book for more details.
2678 * This code could be nicer; ideally it should send a HUP, wait a few
2679 * seconds, then send a INT, and then a KILL signal. But you then
2680 * have to coordinate with the init process, since all processes associated
2681 * with the current tty must be dead before the new getty is allowed
2684 * Now, if it would be correct ;-/ The current code has a nasty hole -
2685 * it doesn't catch files in flight. We may send the descriptor to ourselves
2686 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2688 * Nasty bug: do_SAK is being called in interrupt context. This can
2689 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2691 void __do_SAK(struct tty_struct *tty)
2696 struct task_struct *g, *p;
2697 struct pid *session;
2700 struct fdtable *fdt;
2704 session = tty->session;
2706 tty_ldisc_flush(tty);
2708 tty_driver_flush_buffer(tty);
2710 read_lock(&tasklist_lock);
2711 /* Kill the entire session */
2712 do_each_pid_task(session, PIDTYPE_SID, p) {
2713 printk(KERN_NOTICE "SAK: killed process %d"
2714 " (%s): task_session_nr(p)==tty->session\n",
2715 task_pid_nr(p), p->comm);
2716 send_sig(SIGKILL, p, 1);
2717 } while_each_pid_task(session, PIDTYPE_SID, p);
2718 /* Now kill any processes that happen to have the
2721 do_each_thread(g, p) {
2722 if (p->signal->tty == tty) {
2723 printk(KERN_NOTICE "SAK: killed process %d"
2724 " (%s): task_session_nr(p)==tty->session\n",
2725 task_pid_nr(p), p->comm);
2726 send_sig(SIGKILL, p, 1);
2732 * We don't take a ref to the file, so we must
2733 * hold ->file_lock instead.
2735 spin_lock(&p->files->file_lock);
2736 fdt = files_fdtable(p->files);
2737 for (i = 0; i < fdt->max_fds; i++) {
2738 filp = fcheck_files(p->files, i);
2741 if (filp->f_op->read == tty_read &&
2742 filp->private_data == tty) {
2743 printk(KERN_NOTICE "SAK: killed process %d"
2744 " (%s): fd#%d opened to the tty\n",
2745 task_pid_nr(p), p->comm, i);
2746 force_sig(SIGKILL, p);
2750 spin_unlock(&p->files->file_lock);
2753 } while_each_thread(g, p);
2754 read_unlock(&tasklist_lock);
2758 static void do_SAK_work(struct work_struct *work)
2760 struct tty_struct *tty =
2761 container_of(work, struct tty_struct, SAK_work);
2766 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2767 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2768 * the values which we write to it will be identical to the values which it
2769 * already has. --akpm
2771 void do_SAK(struct tty_struct *tty)
2775 schedule_work(&tty->SAK_work);
2778 EXPORT_SYMBOL(do_SAK);
2781 * initialize_tty_struct
2782 * @tty: tty to initialize
2784 * This subroutine initializes a tty structure that has been newly
2787 * Locking: none - tty in question must not be exposed at this point
2790 void initialize_tty_struct(struct tty_struct *tty,
2791 struct tty_driver *driver, int idx)
2793 memset(tty, 0, sizeof(struct tty_struct));
2794 kref_init(&tty->kref);
2795 tty->magic = TTY_MAGIC;
2796 tty_ldisc_init(tty);
2797 tty->session = NULL;
2799 tty->overrun_time = jiffies;
2800 tty->buf.head = tty->buf.tail = NULL;
2801 tty_buffer_init(tty);
2802 mutex_init(&tty->termios_mutex);
2803 init_waitqueue_head(&tty->write_wait);
2804 init_waitqueue_head(&tty->read_wait);
2805 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2806 mutex_init(&tty->atomic_read_lock);
2807 mutex_init(&tty->atomic_write_lock);
2808 spin_lock_init(&tty->read_lock);
2809 spin_lock_init(&tty->ctrl_lock);
2810 INIT_LIST_HEAD(&tty->tty_files);
2811 INIT_WORK(&tty->SAK_work, do_SAK_work);
2813 tty->driver = driver;
2814 tty->ops = driver->ops;
2816 tty_line_name(driver, idx, tty->name);
2820 * tty_put_char - write one character to a tty
2824 * Write one byte to the tty using the provided put_char method
2825 * if present. Returns the number of characters successfully output.
2827 * Note: the specific put_char operation in the driver layer may go
2828 * away soon. Don't call it directly, use this method
2831 int tty_put_char(struct tty_struct *tty, unsigned char ch)
2833 if (tty->ops->put_char)
2834 return tty->ops->put_char(tty, ch);
2835 return tty->ops->write(tty, &ch, 1);
2837 EXPORT_SYMBOL_GPL(tty_put_char);
2839 struct class *tty_class;
2842 * tty_register_device - register a tty device
2843 * @driver: the tty driver that describes the tty device
2844 * @index: the index in the tty driver for this tty device
2845 * @device: a struct device that is associated with this tty device.
2846 * This field is optional, if there is no known struct device
2847 * for this tty device it can be set to NULL safely.
2849 * Returns a pointer to the struct device for this tty device
2850 * (or ERR_PTR(-EFOO) on error).
2852 * This call is required to be made to register an individual tty device
2853 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2854 * that bit is not set, this function should not be called by a tty
2860 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
2861 struct device *device)
2864 dev_t dev = MKDEV(driver->major, driver->minor_start) + index;
2866 if (index >= driver->num) {
2867 printk(KERN_ERR "Attempt to register invalid tty line number "
2869 return ERR_PTR(-EINVAL);
2872 if (driver->type == TTY_DRIVER_TYPE_PTY)
2873 pty_line_name(driver, index, name);
2875 tty_line_name(driver, index, name);
2877 return device_create_drvdata(tty_class, device, dev, NULL, name);
2879 EXPORT_SYMBOL(tty_register_device);
2882 * tty_unregister_device - unregister a tty device
2883 * @driver: the tty driver that describes the tty device
2884 * @index: the index in the tty driver for this tty device
2886 * If a tty device is registered with a call to tty_register_device() then
2887 * this function must be called when the tty device is gone.
2892 void tty_unregister_device(struct tty_driver *driver, unsigned index)
2894 device_destroy(tty_class,
2895 MKDEV(driver->major, driver->minor_start) + index);
2897 EXPORT_SYMBOL(tty_unregister_device);
2899 struct tty_driver *alloc_tty_driver(int lines)
2901 struct tty_driver *driver;
2903 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
2905 kref_init(&driver->kref);
2906 driver->magic = TTY_DRIVER_MAGIC;
2907 driver->num = lines;
2908 /* later we'll move allocation of tables here */
2912 EXPORT_SYMBOL(alloc_tty_driver);
2914 static void destruct_tty_driver(struct kref *kref)
2916 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
2918 struct ktermios *tp;
2921 if (driver->flags & TTY_DRIVER_INSTALLED) {
2923 * Free the termios and termios_locked structures because
2924 * we don't want to get memory leaks when modular tty
2925 * drivers are removed from the kernel.
2927 for (i = 0; i < driver->num; i++) {
2928 tp = driver->termios[i];
2930 driver->termios[i] = NULL;
2933 tp = driver->termios_locked[i];
2935 driver->termios_locked[i] = NULL;
2938 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
2939 tty_unregister_device(driver, i);
2942 proc_tty_unregister_driver(driver);
2943 driver->ttys = NULL;
2944 driver->termios = driver->termios_locked = NULL;
2946 cdev_del(&driver->cdev);
2951 void tty_driver_kref_put(struct tty_driver *driver)
2953 kref_put(&driver->kref, destruct_tty_driver);
2955 EXPORT_SYMBOL(tty_driver_kref_put);
2957 void tty_set_operations(struct tty_driver *driver,
2958 const struct tty_operations *op)
2962 EXPORT_SYMBOL(tty_set_operations);
2964 void put_tty_driver(struct tty_driver *d)
2966 tty_driver_kref_put(d);
2968 EXPORT_SYMBOL(put_tty_driver);
2971 * Called by a tty driver to register itself.
2973 int tty_register_driver(struct tty_driver *driver)
2980 if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) {
2981 p = kzalloc(driver->num * 3 * sizeof(void *), GFP_KERNEL);
2986 if (!driver->major) {
2987 error = alloc_chrdev_region(&dev, driver->minor_start,
2988 driver->num, driver->name);
2990 driver->major = MAJOR(dev);
2991 driver->minor_start = MINOR(dev);
2994 dev = MKDEV(driver->major, driver->minor_start);
2995 error = register_chrdev_region(dev, driver->num, driver->name);
3003 driver->ttys = (struct tty_struct **)p;
3004 driver->termios = (struct ktermios **)(p + driver->num);
3005 driver->termios_locked = (struct ktermios **)
3006 (p + driver->num * 2);
3008 driver->ttys = NULL;
3009 driver->termios = NULL;
3010 driver->termios_locked = NULL;
3013 cdev_init(&driver->cdev, &tty_fops);
3014 driver->cdev.owner = driver->owner;
3015 error = cdev_add(&driver->cdev, dev, driver->num);
3017 unregister_chrdev_region(dev, driver->num);
3018 driver->ttys = NULL;
3019 driver->termios = driver->termios_locked = NULL;
3024 mutex_lock(&tty_mutex);
3025 list_add(&driver->tty_drivers, &tty_drivers);
3026 mutex_unlock(&tty_mutex);
3028 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3029 for (i = 0; i < driver->num; i++)
3030 tty_register_device(driver, i, NULL);
3032 proc_tty_register_driver(driver);
3033 driver->flags |= TTY_DRIVER_INSTALLED;
3037 EXPORT_SYMBOL(tty_register_driver);
3040 * Called by a tty driver to unregister itself.
3042 int tty_unregister_driver(struct tty_driver *driver)
3046 if (driver->refcount)
3049 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3051 mutex_lock(&tty_mutex);
3052 list_del(&driver->tty_drivers);
3053 mutex_unlock(&tty_mutex);
3057 EXPORT_SYMBOL(tty_unregister_driver);
3059 dev_t tty_devnum(struct tty_struct *tty)
3061 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3063 EXPORT_SYMBOL(tty_devnum);
3065 void proc_clear_tty(struct task_struct *p)
3067 struct tty_struct *tty;
3068 spin_lock_irq(&p->sighand->siglock);
3069 tty = p->signal->tty;
3070 p->signal->tty = NULL;
3071 spin_unlock_irq(&p->sighand->siglock);
3075 /* Called under the sighand lock */
3077 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3080 unsigned long flags;
3081 /* We should not have a session or pgrp to put here but.... */
3082 spin_lock_irqsave(&tty->ctrl_lock, flags);
3083 put_pid(tty->session);
3085 tty->pgrp = get_pid(task_pgrp(tsk));
3086 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3087 tty->session = get_pid(task_session(tsk));
3088 if (tsk->signal->tty) {
3089 printk(KERN_DEBUG "tty not NULL!!\n");
3090 tty_kref_put(tsk->signal->tty);
3093 put_pid(tsk->signal->tty_old_pgrp);
3094 tsk->signal->tty = tty_kref_get(tty);
3095 tsk->signal->tty_old_pgrp = NULL;
3098 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3100 spin_lock_irq(&tsk->sighand->siglock);
3101 __proc_set_tty(tsk, tty);
3102 spin_unlock_irq(&tsk->sighand->siglock);
3105 struct tty_struct *get_current_tty(void)
3107 struct tty_struct *tty;
3108 unsigned long flags;
3110 spin_lock_irqsave(¤t->sighand->siglock, flags);
3111 tty = tty_kref_get(current->signal->tty);
3112 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
3115 EXPORT_SYMBOL_GPL(get_current_tty);
3117 void tty_default_fops(struct file_operations *fops)
3123 * Initialize the console device. This is called *early*, so
3124 * we can't necessarily depend on lots of kernel help here.
3125 * Just do some early initializations, and do the complex setup
3128 void __init console_init(void)
3132 /* Setup the default TTY line discipline. */
3136 * set up the console device so that later boot sequences can
3137 * inform about problems etc..
3139 call = __con_initcall_start;
3140 while (call < __con_initcall_end) {
3146 static int __init tty_class_init(void)
3148 tty_class = class_create(THIS_MODULE, "tty");
3149 if (IS_ERR(tty_class))
3150 return PTR_ERR(tty_class);
3154 postcore_initcall(tty_class_init);
3156 /* 3/2004 jmc: why do these devices exist? */
3158 static struct cdev tty_cdev, console_cdev;
3161 * Ok, now we can initialize the rest of the tty devices and can count
3162 * on memory allocations, interrupts etc..
3164 static int __init tty_init(void)
3166 cdev_init(&tty_cdev, &tty_fops);
3167 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3168 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3169 panic("Couldn't register /dev/tty driver\n");
3170 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL,
3173 cdev_init(&console_cdev, &console_fops);
3174 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3175 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3176 panic("Couldn't register /dev/console driver\n");
3177 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3181 vty_init(&console_fops);
3185 module_init(tty_init);