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 void initialize_tty_struct(struct tty_struct *tty);
141 static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
142 static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
143 ssize_t redirected_tty_write(struct file *, const char __user *,
145 static unsigned int tty_poll(struct file *, poll_table *);
146 static int tty_open(struct inode *, struct file *);
147 static int tty_release(struct inode *, struct file *);
148 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
150 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
153 #define tty_compat_ioctl NULL
155 static int tty_fasync(int fd, struct file *filp, int on);
156 static void release_tty(struct tty_struct *tty, int idx);
157 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
158 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
161 * alloc_tty_struct - allocate a tty object
163 * Return a new empty tty structure. The data fields have not
164 * been initialized in any way but has been zeroed
169 static struct tty_struct *alloc_tty_struct(void)
171 return kzalloc(sizeof(struct tty_struct), GFP_KERNEL);
175 * free_tty_struct - free a disused tty
176 * @tty: tty struct to free
178 * Free the write buffers, tty queue and tty memory itself.
180 * Locking: none. Must be called after tty is definitely unused
183 static inline void free_tty_struct(struct tty_struct *tty)
185 kfree(tty->write_buf);
186 tty_buffer_free_all(tty);
190 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
193 * tty_name - return tty naming
194 * @tty: tty structure
195 * @buf: buffer for output
197 * Convert a tty structure into a name. The name reflects the kernel
198 * naming policy and if udev is in use may not reflect user space
203 char *tty_name(struct tty_struct *tty, char *buf)
205 if (!tty) /* Hmm. NULL pointer. That's fun. */
206 strcpy(buf, "NULL tty");
208 strcpy(buf, tty->name);
212 EXPORT_SYMBOL(tty_name);
214 int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
217 #ifdef TTY_PARANOIA_CHECK
220 "null TTY for (%d:%d) in %s\n",
221 imajor(inode), iminor(inode), routine);
224 if (tty->magic != TTY_MAGIC) {
226 "bad magic number for tty struct (%d:%d) in %s\n",
227 imajor(inode), iminor(inode), routine);
234 static int check_tty_count(struct tty_struct *tty, const char *routine)
236 #ifdef CHECK_TTY_COUNT
241 list_for_each(p, &tty->tty_files) {
245 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
246 tty->driver->subtype == PTY_TYPE_SLAVE &&
247 tty->link && tty->link->count)
249 if (tty->count != count) {
250 printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) "
251 "!= #fd's(%d) in %s\n",
252 tty->name, tty->count, count, routine);
260 * get_tty_driver - find device of a tty
261 * @dev_t: device identifier
262 * @index: returns the index of the tty
264 * This routine returns a tty driver structure, given a device number
265 * and also passes back the index number.
267 * Locking: caller must hold tty_mutex
270 static struct tty_driver *get_tty_driver(dev_t device, int *index)
272 struct tty_driver *p;
274 list_for_each_entry(p, &tty_drivers, tty_drivers) {
275 dev_t base = MKDEV(p->major, p->minor_start);
276 if (device < base || device >= base + p->num)
278 *index = device - base;
284 #ifdef CONFIG_CONSOLE_POLL
287 * tty_find_polling_driver - find device of a polled tty
288 * @name: name string to match
289 * @line: pointer to resulting tty line nr
291 * This routine returns a tty driver structure, given a name
292 * and the condition that the tty driver is capable of polled
295 struct tty_driver *tty_find_polling_driver(char *name, int *line)
297 struct tty_driver *p, *res = NULL;
302 for (str = name; *str; str++)
303 if ((*str >= '0' && *str <= '9') || *str == ',')
309 tty_line = simple_strtoul(str, &str, 10);
311 mutex_lock(&tty_mutex);
312 /* Search through the tty devices to look for a match */
313 list_for_each_entry(p, &tty_drivers, tty_drivers) {
314 if (strncmp(name, p->name, len) != 0)
321 if (tty_line >= 0 && tty_line <= p->num && p->ops &&
322 p->ops->poll_init && !p->ops->poll_init(p, tty_line, str)) {
328 mutex_unlock(&tty_mutex);
332 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
336 * tty_check_change - check for POSIX terminal changes
339 * If we try to write to, or set the state of, a terminal and we're
340 * not in the foreground, send a SIGTTOU. If the signal is blocked or
341 * ignored, go ahead and perform the operation. (POSIX 7.2)
346 int tty_check_change(struct tty_struct *tty)
351 if (current->signal->tty != tty)
354 spin_lock_irqsave(&tty->ctrl_lock, flags);
357 printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
360 if (task_pgrp(current) == tty->pgrp)
362 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
363 if (is_ignored(SIGTTOU))
365 if (is_current_pgrp_orphaned()) {
369 kill_pgrp(task_pgrp(current), SIGTTOU, 1);
370 set_thread_flag(TIF_SIGPENDING);
375 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
379 EXPORT_SYMBOL(tty_check_change);
381 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
382 size_t count, loff_t *ppos)
387 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
388 size_t count, loff_t *ppos)
393 /* No kernel lock held - none needed ;) */
394 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
396 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
399 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
402 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
405 static long hung_up_tty_compat_ioctl(struct file *file,
406 unsigned int cmd, unsigned long arg)
408 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
411 static const struct file_operations tty_fops = {
416 .unlocked_ioctl = tty_ioctl,
417 .compat_ioctl = tty_compat_ioctl,
419 .release = tty_release,
420 .fasync = tty_fasync,
423 static const struct file_operations console_fops = {
426 .write = redirected_tty_write,
428 .unlocked_ioctl = tty_ioctl,
429 .compat_ioctl = tty_compat_ioctl,
431 .release = tty_release,
432 .fasync = tty_fasync,
435 static const struct file_operations hung_up_tty_fops = {
437 .read = hung_up_tty_read,
438 .write = hung_up_tty_write,
439 .poll = hung_up_tty_poll,
440 .unlocked_ioctl = hung_up_tty_ioctl,
441 .compat_ioctl = hung_up_tty_compat_ioctl,
442 .release = tty_release,
445 static DEFINE_SPINLOCK(redirect_lock);
446 static struct file *redirect;
449 * tty_wakeup - request more data
452 * Internal and external helper for wakeups of tty. This function
453 * informs the line discipline if present that the driver is ready
454 * to receive more output data.
457 void tty_wakeup(struct tty_struct *tty)
459 struct tty_ldisc *ld;
461 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
462 ld = tty_ldisc_ref(tty);
464 if (ld->ops->write_wakeup)
465 ld->ops->write_wakeup(tty);
469 wake_up_interruptible(&tty->write_wait);
472 EXPORT_SYMBOL_GPL(tty_wakeup);
475 * tty_ldisc_flush - flush line discipline queue
478 * Flush the line discipline queue (if any) for this tty. If there
479 * is no line discipline active this is a no-op.
482 void tty_ldisc_flush(struct tty_struct *tty)
484 struct tty_ldisc *ld = tty_ldisc_ref(tty);
486 if (ld->ops->flush_buffer)
487 ld->ops->flush_buffer(tty);
490 tty_buffer_flush(tty);
493 EXPORT_SYMBOL_GPL(tty_ldisc_flush);
496 * tty_reset_termios - reset terminal state
499 * Restore a terminal to the driver default state
502 static void tty_reset_termios(struct tty_struct *tty)
504 mutex_lock(&tty->termios_mutex);
505 *tty->termios = tty->driver->init_termios;
506 tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
507 tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
508 mutex_unlock(&tty->termios_mutex);
512 * do_tty_hangup - actual handler for hangup events
515 * This can be called by the "eventd" kernel thread. That is process
516 * synchronous but doesn't hold any locks, so we need to make sure we
517 * have the appropriate locks for what we're doing.
519 * The hangup event clears any pending redirections onto the hung up
520 * device. It ensures future writes will error and it does the needed
521 * line discipline hangup and signal delivery. The tty object itself
526 * redirect lock for undoing redirection
527 * file list lock for manipulating list of ttys
528 * tty_ldisc_lock from called functions
529 * termios_mutex resetting termios data
530 * tasklist_lock to walk task list for hangup event
531 * ->siglock to protect ->signal/->sighand
533 static void do_tty_hangup(struct work_struct *work)
535 struct tty_struct *tty =
536 container_of(work, struct tty_struct, hangup_work);
537 struct file *cons_filp = NULL;
538 struct file *filp, *f = NULL;
539 struct task_struct *p;
540 struct tty_ldisc *ld;
541 int closecount = 0, n;
548 /* inuse_filps is protected by the single kernel lock */
551 spin_lock(&redirect_lock);
552 if (redirect && redirect->private_data == tty) {
556 spin_unlock(&redirect_lock);
558 check_tty_count(tty, "do_tty_hangup");
560 /* This breaks for file handles being sent over AF_UNIX sockets ? */
561 list_for_each_entry(filp, &tty->tty_files, f_u.fu_list) {
562 if (filp->f_op->write == redirected_tty_write)
564 if (filp->f_op->write != tty_write)
567 tty_fasync(-1, filp, 0); /* can't block */
568 filp->f_op = &hung_up_tty_fops;
572 * FIXME! What are the locking issues here? This may me overdoing
573 * things... This question is especially important now that we've
574 * removed the irqlock.
576 ld = tty_ldisc_ref(tty);
578 /* We may have no line discipline at this point */
579 if (ld->ops->flush_buffer)
580 ld->ops->flush_buffer(tty);
581 tty_driver_flush_buffer(tty);
582 if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) &&
583 ld->ops->write_wakeup)
584 ld->ops->write_wakeup(tty);
586 ld->ops->hangup(tty);
589 * FIXME: Once we trust the LDISC code better we can wait here for
590 * ldisc completion and fix the driver call race
592 wake_up_interruptible(&tty->write_wait);
593 wake_up_interruptible(&tty->read_wait);
595 * Shutdown the current line discipline, and reset it to
598 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
599 tty_reset_termios(tty);
600 /* Defer ldisc switch */
601 /* tty_deferred_ldisc_switch(N_TTY);
603 This should get done automatically when the port closes and
604 tty_release is called */
606 read_lock(&tasklist_lock);
608 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
609 spin_lock_irq(&p->sighand->siglock);
610 if (p->signal->tty == tty) {
611 p->signal->tty = NULL;
612 /* We defer the dereferences outside fo
616 if (!p->signal->leader) {
617 spin_unlock_irq(&p->sighand->siglock);
620 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
621 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
622 put_pid(p->signal->tty_old_pgrp); /* A noop */
623 spin_lock_irqsave(&tty->ctrl_lock, flags);
625 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
626 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
627 spin_unlock_irq(&p->sighand->siglock);
628 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
630 read_unlock(&tasklist_lock);
632 spin_lock_irqsave(&tty->ctrl_lock, flags);
634 put_pid(tty->session);
638 tty->ctrl_status = 0;
639 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
641 /* Account for the p->signal references we killed */
646 * If one of the devices matches a console pointer, we
647 * cannot just call hangup() because that will cause
648 * tty->count and state->count to go out of sync.
649 * So we just call close() the right number of times.
653 for (n = 0; n < closecount; n++)
654 tty->ops->close(tty, cons_filp);
655 } else if (tty->ops->hangup)
656 (tty->ops->hangup)(tty);
658 * We don't want to have driver/ldisc interactions beyond
659 * the ones we did here. The driver layer expects no
660 * calls after ->hangup() from the ldisc side. However we
661 * can't yet guarantee all that.
663 set_bit(TTY_HUPPED, &tty->flags);
665 tty_ldisc_enable(tty);
674 * tty_hangup - trigger a hangup event
675 * @tty: tty to hangup
677 * A carrier loss (virtual or otherwise) has occurred on this like
678 * schedule a hangup sequence to run after this event.
681 void tty_hangup(struct tty_struct *tty)
683 #ifdef TTY_DEBUG_HANGUP
685 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
687 schedule_work(&tty->hangup_work);
690 EXPORT_SYMBOL(tty_hangup);
693 * tty_vhangup - process vhangup
694 * @tty: tty to hangup
696 * The user has asked via system call for the terminal to be hung up.
697 * We do this synchronously so that when the syscall returns the process
698 * is complete. That guarantee is necessary for security reasons.
701 void tty_vhangup(struct tty_struct *tty)
703 #ifdef TTY_DEBUG_HANGUP
706 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
708 do_tty_hangup(&tty->hangup_work);
711 EXPORT_SYMBOL(tty_vhangup);
714 * tty_vhangup_self - process vhangup for own ctty
716 * Perform a vhangup on the current controlling tty
719 void tty_vhangup_self(void)
721 struct tty_struct *tty;
723 tty = get_current_tty();
731 * tty_hung_up_p - was tty hung up
732 * @filp: file pointer of tty
734 * Return true if the tty has been subject to a vhangup or a carrier
738 int tty_hung_up_p(struct file *filp)
740 return (filp->f_op == &hung_up_tty_fops);
743 EXPORT_SYMBOL(tty_hung_up_p);
745 static void session_clear_tty(struct pid *session)
747 struct task_struct *p;
748 do_each_pid_task(session, PIDTYPE_SID, p) {
750 } while_each_pid_task(session, PIDTYPE_SID, p);
754 * disassociate_ctty - disconnect controlling tty
755 * @on_exit: true if exiting so need to "hang up" the session
757 * This function is typically called only by the session leader, when
758 * it wants to disassociate itself from its controlling tty.
760 * It performs the following functions:
761 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
762 * (2) Clears the tty from being controlling the session
763 * (3) Clears the controlling tty for all processes in the
766 * The argument on_exit is set to 1 if called when a process is
767 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
770 * BKL is taken for hysterical raisins
771 * tty_mutex is taken to protect tty
772 * ->siglock is taken to protect ->signal/->sighand
773 * tasklist_lock is taken to walk process list for sessions
774 * ->siglock is taken to protect ->signal/->sighand
777 void disassociate_ctty(int on_exit)
779 struct tty_struct *tty;
780 struct pid *tty_pgrp = NULL;
783 tty = get_current_tty();
785 tty_pgrp = get_pid(tty->pgrp);
787 if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY)
791 } else if (on_exit) {
792 struct pid *old_pgrp;
793 spin_lock_irq(¤t->sighand->siglock);
794 old_pgrp = current->signal->tty_old_pgrp;
795 current->signal->tty_old_pgrp = NULL;
796 spin_unlock_irq(¤t->sighand->siglock);
798 kill_pgrp(old_pgrp, SIGHUP, on_exit);
799 kill_pgrp(old_pgrp, SIGCONT, on_exit);
805 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
807 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
811 spin_lock_irq(¤t->sighand->siglock);
812 put_pid(current->signal->tty_old_pgrp);
813 current->signal->tty_old_pgrp = NULL;
814 spin_unlock_irq(¤t->sighand->siglock);
816 tty = get_current_tty();
819 spin_lock_irqsave(&tty->ctrl_lock, flags);
820 put_pid(tty->session);
824 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
827 #ifdef TTY_DEBUG_HANGUP
828 printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
833 /* Now clear signal->tty under the lock */
834 read_lock(&tasklist_lock);
835 session_clear_tty(task_session(current));
836 read_unlock(&tasklist_lock);
841 * no_tty - Ensure the current process does not have a controlling tty
845 struct task_struct *tsk = current;
847 if (tsk->signal->leader)
848 disassociate_ctty(0);
855 * stop_tty - propagate flow control
858 * Perform flow control to the driver. For PTY/TTY pairs we
859 * must also propagate the TIOCKPKT status. May be called
860 * on an already stopped device and will not re-call the driver
863 * This functionality is used by both the line disciplines for
864 * halting incoming flow and by the driver. It may therefore be
865 * called from any context, may be under the tty atomic_write_lock
869 * Uses the tty control lock internally
872 void stop_tty(struct tty_struct *tty)
875 spin_lock_irqsave(&tty->ctrl_lock, flags);
877 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
881 if (tty->link && tty->link->packet) {
882 tty->ctrl_status &= ~TIOCPKT_START;
883 tty->ctrl_status |= TIOCPKT_STOP;
884 wake_up_interruptible(&tty->link->read_wait);
886 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
888 (tty->ops->stop)(tty);
891 EXPORT_SYMBOL(stop_tty);
894 * start_tty - propagate flow control
897 * Start a tty that has been stopped if at all possible. Perform
898 * any necessary wakeups and propagate the TIOCPKT status. If this
899 * is the tty was previous stopped and is being started then the
900 * driver start method is invoked and the line discipline woken.
906 void start_tty(struct tty_struct *tty)
909 spin_lock_irqsave(&tty->ctrl_lock, flags);
910 if (!tty->stopped || tty->flow_stopped) {
911 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
915 if (tty->link && tty->link->packet) {
916 tty->ctrl_status &= ~TIOCPKT_STOP;
917 tty->ctrl_status |= TIOCPKT_START;
918 wake_up_interruptible(&tty->link->read_wait);
920 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
922 (tty->ops->start)(tty);
923 /* If we have a running line discipline it may need kicking */
927 EXPORT_SYMBOL(start_tty);
930 * tty_read - read method for tty device files
931 * @file: pointer to tty file
933 * @count: size of user buffer
936 * Perform the read system call function on this terminal device. Checks
937 * for hung up devices before calling the line discipline method.
940 * Locks the line discipline internally while needed. Multiple
941 * read calls may be outstanding in parallel.
944 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
948 struct tty_struct *tty;
950 struct tty_ldisc *ld;
952 tty = (struct tty_struct *)file->private_data;
953 inode = file->f_path.dentry->d_inode;
954 if (tty_paranoia_check(tty, inode, "tty_read"))
956 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
959 /* We want to wait for the line discipline to sort out in this
961 ld = tty_ldisc_ref_wait(tty);
963 i = (ld->ops->read)(tty, file, buf, count);
968 inode->i_atime = current_fs_time(inode->i_sb);
972 void tty_write_unlock(struct tty_struct *tty)
974 mutex_unlock(&tty->atomic_write_lock);
975 wake_up_interruptible(&tty->write_wait);
978 int tty_write_lock(struct tty_struct *tty, int ndelay)
980 if (!mutex_trylock(&tty->atomic_write_lock)) {
983 if (mutex_lock_interruptible(&tty->atomic_write_lock))
990 * Split writes up in sane blocksizes to avoid
991 * denial-of-service type attacks
993 static inline ssize_t do_tty_write(
994 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
995 struct tty_struct *tty,
997 const char __user *buf,
1000 ssize_t ret, written = 0;
1003 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
1008 * We chunk up writes into a temporary buffer. This
1009 * simplifies low-level drivers immensely, since they
1010 * don't have locking issues and user mode accesses.
1012 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1015 * The default chunk-size is 2kB, because the NTTY
1016 * layer has problems with bigger chunks. It will
1017 * claim to be able to handle more characters than
1020 * FIXME: This can probably go away now except that 64K chunks
1021 * are too likely to fail unless switched to vmalloc...
1024 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1029 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1030 if (tty->write_cnt < chunk) {
1036 buf = kmalloc(chunk, GFP_KERNEL);
1041 kfree(tty->write_buf);
1042 tty->write_cnt = chunk;
1043 tty->write_buf = buf;
1046 /* Do the write .. */
1048 size_t size = count;
1052 if (copy_from_user(tty->write_buf, buf, size))
1054 ret = write(tty, file, tty->write_buf, size);
1063 if (signal_pending(current))
1068 struct inode *inode = file->f_path.dentry->d_inode;
1069 inode->i_mtime = current_fs_time(inode->i_sb);
1073 tty_write_unlock(tty);
1078 * tty_write_message - write a message to a certain tty, not just the console.
1079 * @tty: the destination tty_struct
1080 * @msg: the message to write
1082 * This is used for messages that need to be redirected to a specific tty.
1083 * We don't put it into the syslog queue right now maybe in the future if
1086 * We must still hold the BKL and test the CLOSING flag for the moment.
1089 void tty_write_message(struct tty_struct *tty, char *msg)
1093 mutex_lock(&tty->atomic_write_lock);
1094 if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags))
1095 tty->ops->write(tty, msg, strlen(msg));
1096 tty_write_unlock(tty);
1104 * tty_write - write method for tty device file
1105 * @file: tty file pointer
1106 * @buf: user data to write
1107 * @count: bytes to write
1110 * Write data to a tty device via the line discipline.
1113 * Locks the line discipline as required
1114 * Writes to the tty driver are serialized by the atomic_write_lock
1115 * and are then processed in chunks to the device. The line discipline
1116 * write method will not be involked in parallel for each device
1117 * The line discipline write method is called under the big
1118 * kernel lock for historical reasons. New code should not rely on this.
1121 static ssize_t tty_write(struct file *file, const char __user *buf,
1122 size_t count, loff_t *ppos)
1124 struct tty_struct *tty;
1125 struct inode *inode = file->f_path.dentry->d_inode;
1127 struct tty_ldisc *ld;
1129 tty = (struct tty_struct *)file->private_data;
1130 if (tty_paranoia_check(tty, inode, "tty_write"))
1132 if (!tty || !tty->ops->write ||
1133 (test_bit(TTY_IO_ERROR, &tty->flags)))
1135 /* Short term debug to catch buggy drivers */
1136 if (tty->ops->write_room == NULL)
1137 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1139 ld = tty_ldisc_ref_wait(tty);
1140 if (!ld->ops->write)
1143 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1144 tty_ldisc_deref(ld);
1148 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1149 size_t count, loff_t *ppos)
1151 struct file *p = NULL;
1153 spin_lock(&redirect_lock);
1158 spin_unlock(&redirect_lock);
1162 res = vfs_write(p, buf, count, &p->f_pos);
1166 return tty_write(file, buf, count, ppos);
1169 static char ptychar[] = "pqrstuvwxyzabcde";
1172 * pty_line_name - generate name for a pty
1173 * @driver: the tty driver in use
1174 * @index: the minor number
1175 * @p: output buffer of at least 6 bytes
1177 * Generate a name from a driver reference and write it to the output
1182 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1184 int i = index + driver->name_base;
1185 /* ->name is initialized to "ttyp", but "tty" is expected */
1186 sprintf(p, "%s%c%x",
1187 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1188 ptychar[i >> 4 & 0xf], i & 0xf);
1192 * pty_line_name - generate name for a tty
1193 * @driver: the tty driver in use
1194 * @index: the minor number
1195 * @p: output buffer of at least 7 bytes
1197 * Generate a name from a driver reference and write it to the output
1202 static void tty_line_name(struct tty_driver *driver, int index, char *p)
1204 sprintf(p, "%s%d", driver->name, index + driver->name_base);
1208 * find_tty() - find an existing tty, if any
1209 * @driver: the driver for the tty
1210 * @idx: the minor number
1212 * Return the tty, if found or ERR_PTR() otherwise.
1214 * Locking: tty_mutex must be held. If tty is found, the mutex must
1215 * be held until the 'fast-open' is also done.
1217 struct tty_struct *find_tty(struct tty_driver *driver, int idx)
1219 struct tty_struct *tty;
1221 /* check whether we're reopening an existing tty */
1222 if (driver->flags & TTY_DRIVER_DEVPTS_MEM) {
1223 tty = devpts_get_tty(idx);
1225 * If we don't have a tty here on a slave open, it's because
1226 * the master already started the close process and there's
1227 * no relation between devpts file and tty anymore.
1229 if (!tty && driver->subtype == PTY_TYPE_SLAVE)
1230 return ERR_PTR(-EIO);
1233 * tty is safe on because we are called with tty_mutex held
1234 * and release_dev() won't change tty->count or tty->flags
1235 * without grabbing tty_mutex.
1237 if (tty && driver->subtype == PTY_TYPE_MASTER)
1240 tty = driver->ttys[idx];
1245 * fast_tty_open() - fast re-open of an open tty
1246 * @tty - the tty to open
1248 * Return 0 on success, -errno on error.
1250 * Locking: tty_mutex must be held from the time the tty was found
1251 * till this open completes.
1253 static int fast_tty_open(struct tty_struct *tty)
1255 struct tty_driver *driver = tty->driver;
1257 if (test_bit(TTY_CLOSING, &tty->flags))
1260 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1261 driver->subtype == PTY_TYPE_MASTER) {
1263 * special case for PTY masters: only one open permitted,
1264 * and the slave side open count is incremented as well.
1272 tty->driver = driver; /* N.B. why do this every time?? */
1275 if (!test_bit(TTY_LDISC, &tty->flags))
1276 printk(KERN_ERR "fast_tty_open: no ldisc\n");
1282 * tty_init_dev - initialise a tty device
1283 * @driver: tty driver we are opening a device on
1284 * @idx: device index
1285 * @ret_tty: returned tty structure
1286 * @first_ok: ok to open a new device (used by ptmx)
1288 * Prepare a tty device. This may not be a "new" clean device but
1289 * could also be an active device. The pty drivers require special
1290 * handling because of this.
1293 * The function is called under the tty_mutex, which
1294 * protects us from the tty struct or driver itself going away.
1296 * On exit the tty device has the line discipline attached and
1297 * a reference count of 1. If a pair was created for pty/tty use
1298 * and the other was a pty master then it too has a reference count of 1.
1300 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1301 * failed open. The new code protects the open with a mutex, so it's
1302 * really quite straightforward. The mutex locking can probably be
1303 * relaxed for the (most common) case of reopening a tty.
1306 int tty_init_dev(struct tty_driver *driver, int idx,
1307 struct tty_struct **ret_tty, int first_ok)
1309 struct tty_struct *tty, *o_tty;
1310 struct ktermios *tp, **tp_loc, *o_tp, **o_tp_loc;
1311 struct ktermios *ltp, **ltp_loc, *o_ltp, **o_ltp_loc;
1314 /* check whether we're reopening an existing tty */
1315 tty = find_tty(driver, idx);
1317 retval = PTR_ERR(tty);
1322 retval = fast_tty_open(tty);
1329 /* Check if pty master is being opened multiple times */
1330 if (driver->subtype == PTY_TYPE_MASTER &&
1331 (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok) {
1336 * First time open is complex, especially for PTY devices.
1337 * This code guarantees that either everything succeeds and the
1338 * TTY is ready for operation, or else the table slots are vacated
1339 * and the allocated memory released. (Except that the termios
1340 * and locked termios may be retained.)
1343 if (!try_module_get(driver->owner)) {
1352 tty = alloc_tty_struct();
1355 initialize_tty_struct(tty);
1356 tty->driver = driver;
1357 tty->ops = driver->ops;
1359 tty_line_name(driver, idx, tty->name);
1361 if (driver->flags & TTY_DRIVER_DEVPTS_MEM) {
1362 tp_loc = &tty->termios;
1363 ltp_loc = &tty->termios_locked;
1365 tp_loc = &driver->termios[idx];
1366 ltp_loc = &driver->termios_locked[idx];
1370 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1373 *tp = driver->init_termios;
1377 ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL);
1382 if (driver->type == TTY_DRIVER_TYPE_PTY) {
1383 o_tty = alloc_tty_struct();
1386 if (!try_module_get(driver->other->owner)) {
1387 /* This cannot in fact currently happen */
1388 free_tty_struct(o_tty);
1392 initialize_tty_struct(o_tty);
1393 o_tty->driver = driver->other;
1394 o_tty->ops = driver->ops;
1396 tty_line_name(driver->other, idx, o_tty->name);
1398 if (driver->flags & TTY_DRIVER_DEVPTS_MEM) {
1399 o_tp_loc = &o_tty->termios;
1400 o_ltp_loc = &o_tty->termios_locked;
1402 o_tp_loc = &driver->other->termios[idx];
1403 o_ltp_loc = &driver->other->termios_locked[idx];
1407 o_tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1410 *o_tp = driver->other->init_termios;
1414 o_ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL);
1420 * Everything allocated ... set up the o_tty structure.
1422 if (!(driver->other->flags & TTY_DRIVER_DEVPTS_MEM))
1423 driver->other->ttys[idx] = o_tty;
1428 o_tty->termios = *o_tp_loc;
1429 o_tty->termios_locked = *o_ltp_loc;
1430 driver->other->refcount++;
1431 if (driver->subtype == PTY_TYPE_MASTER)
1434 /* Establish the links in both directions */
1440 * All structures have been allocated, so now we install them.
1441 * Failures after this point use release_tty to clean up, so
1442 * there's no need to null out the local pointers.
1444 if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM))
1445 driver->ttys[idx] = tty;
1451 tty->termios = *tp_loc;
1452 tty->termios_locked = *ltp_loc;
1453 /* Compatibility until drivers always set this */
1454 tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
1455 tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
1460 * Structures all installed ... call the ldisc open routines.
1461 * If we fail here just call release_tty to clean up. No need
1462 * to decrement the use counts, as release_tty doesn't care.
1465 retval = tty_ldisc_setup(tty, o_tty);
1468 goto release_mem_out;
1472 /* All paths come through here to release the mutex */
1476 /* Release locally allocated memory ... nothing placed in slots */
1480 module_put(o_tty->driver->owner);
1481 free_tty_struct(o_tty);
1485 free_tty_struct(tty);
1488 module_put(driver->owner);
1492 /* call the tty release_tty routine to clean out this slot */
1494 if (printk_ratelimit())
1495 printk(KERN_INFO "tty_init_dev: ldisc open failed, "
1496 "clearing slot %d\n", idx);
1497 release_tty(tty, idx);
1501 void tty_free_termios(struct tty_struct *tty)
1503 struct ktermios *tp;
1504 int idx = tty->index;
1505 /* Kill this flag and push into drivers for locking etc */
1506 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
1507 /* FIXME: Locking on ->termios array */
1509 tty->driver->termios[idx] = NULL;
1512 tp = tty->termios_locked;
1513 tty->driver->termios_locked[idx] = NULL;
1517 EXPORT_SYMBOL(tty_free_termios);
1519 void tty_shutdown(struct tty_struct *tty)
1521 tty->driver->ttys[tty->index] = NULL;
1522 tty_free_termios(tty);
1524 EXPORT_SYMBOL(tty_shutdown);
1527 * release_one_tty - release tty structure memory
1528 * @kref: kref of tty we are obliterating
1530 * Releases memory associated with a tty structure, and clears out the
1531 * driver table slots. This function is called when a device is no longer
1532 * in use. It also gets called when setup of a device fails.
1535 * tty_mutex - sometimes only
1536 * takes the file list lock internally when working on the list
1537 * of ttys that the driver keeps.
1539 static void release_one_tty(struct kref *kref)
1541 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1542 struct tty_driver *driver = tty->driver;
1544 if (tty->ops->shutdown)
1545 tty->ops->shutdown(tty);
1549 /* FIXME: locking on tty->driver->refcount */
1550 tty->driver->refcount--;
1551 module_put(driver->owner);
1554 list_del_init(&tty->tty_files);
1557 free_tty_struct(tty);
1561 * tty_kref_put - release a tty kref
1564 * Release a reference to a tty device and if need be let the kref
1565 * layer destruct the object for us
1568 void tty_kref_put(struct tty_struct *tty)
1571 kref_put(&tty->kref, release_one_tty);
1573 EXPORT_SYMBOL(tty_kref_put);
1576 * release_tty - release tty structure memory
1578 * Release both @tty and a possible linked partner (think pty pair),
1579 * and decrement the refcount of the backing module.
1582 * tty_mutex - sometimes only
1583 * takes the file list lock internally when working on the list
1584 * of ttys that the driver keeps.
1585 * FIXME: should we require tty_mutex is held here ??
1588 static void release_tty(struct tty_struct *tty, int idx)
1590 /* This should always be true but check for the moment */
1591 WARN_ON(tty->index != idx);
1594 tty_kref_put(tty->link);
1599 * Even releasing the tty structures is a tricky business.. We have
1600 * to be very careful that the structures are all released at the
1601 * same time, as interrupts might otherwise get the wrong pointers.
1603 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1604 * lead to double frees or releasing memory still in use.
1606 void tty_release_dev(struct file *filp)
1608 struct tty_struct *tty, *o_tty;
1609 int pty_master, tty_closing, o_tty_closing, do_sleep;
1614 tty = (struct tty_struct *)filp->private_data;
1615 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode,
1619 check_tty_count(tty, "tty_release_dev");
1621 tty_fasync(-1, filp, 0);
1624 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1625 tty->driver->subtype == PTY_TYPE_MASTER);
1626 devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
1629 #ifdef TTY_PARANOIA_CHECK
1630 if (idx < 0 || idx >= tty->driver->num) {
1631 printk(KERN_DEBUG "tty_release_dev: bad idx when trying to "
1632 "free (%s)\n", tty->name);
1635 if (!(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
1636 if (tty != tty->driver->ttys[idx]) {
1637 printk(KERN_DEBUG "tty_release_dev: driver.table[%d] not tty "
1638 "for (%s)\n", idx, tty->name);
1641 if (tty->termios != tty->driver->termios[idx]) {
1642 printk(KERN_DEBUG "tty_release_dev: driver.termios[%d] not termios "
1647 if (tty->termios_locked != tty->driver->termios_locked[idx]) {
1648 printk(KERN_DEBUG "tty_release_dev: driver.termios_locked[%d] not "
1649 "termios_locked for (%s)\n",
1656 #ifdef TTY_DEBUG_HANGUP
1657 printk(KERN_DEBUG "tty_release_dev of %s (tty count=%d)...",
1658 tty_name(tty, buf), tty->count);
1661 #ifdef TTY_PARANOIA_CHECK
1662 if (tty->driver->other &&
1663 !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
1664 if (o_tty != tty->driver->other->ttys[idx]) {
1665 printk(KERN_DEBUG "tty_release_dev: other->table[%d] "
1666 "not o_tty for (%s)\n",
1670 if (o_tty->termios != tty->driver->other->termios[idx]) {
1671 printk(KERN_DEBUG "tty_release_dev: other->termios[%d] "
1672 "not o_termios for (%s)\n",
1676 if (o_tty->termios_locked !=
1677 tty->driver->other->termios_locked[idx]) {
1678 printk(KERN_DEBUG "tty_release_dev: other->termios_locked["
1679 "%d] not o_termios_locked for (%s)\n",
1683 if (o_tty->link != tty) {
1684 printk(KERN_DEBUG "tty_release_dev: bad pty pointers\n");
1689 if (tty->ops->close)
1690 tty->ops->close(tty, filp);
1693 * Sanity check: if tty->count is going to zero, there shouldn't be
1694 * any waiters on tty->read_wait or tty->write_wait. We test the
1695 * wait queues and kick everyone out _before_ actually starting to
1696 * close. This ensures that we won't block while releasing the tty
1699 * The test for the o_tty closing is necessary, since the master and
1700 * slave sides may close in any order. If the slave side closes out
1701 * first, its count will be one, since the master side holds an open.
1702 * Thus this test wouldn't be triggered at the time the slave closes,
1705 * Note that it's possible for the tty to be opened again while we're
1706 * flushing out waiters. By recalculating the closing flags before
1707 * each iteration we avoid any problems.
1710 /* Guard against races with tty->count changes elsewhere and
1711 opens on /dev/tty */
1713 mutex_lock(&tty_mutex);
1714 tty_closing = tty->count <= 1;
1715 o_tty_closing = o_tty &&
1716 (o_tty->count <= (pty_master ? 1 : 0));
1720 if (waitqueue_active(&tty->read_wait)) {
1721 wake_up(&tty->read_wait);
1724 if (waitqueue_active(&tty->write_wait)) {
1725 wake_up(&tty->write_wait);
1729 if (o_tty_closing) {
1730 if (waitqueue_active(&o_tty->read_wait)) {
1731 wake_up(&o_tty->read_wait);
1734 if (waitqueue_active(&o_tty->write_wait)) {
1735 wake_up(&o_tty->write_wait);
1742 printk(KERN_WARNING "tty_release_dev: %s: read/write wait queue "
1743 "active!\n", tty_name(tty, buf));
1744 mutex_unlock(&tty_mutex);
1749 * The closing flags are now consistent with the open counts on
1750 * both sides, and we've completed the last operation that could
1751 * block, so it's safe to proceed with closing.
1754 if (--o_tty->count < 0) {
1755 printk(KERN_WARNING "tty_release_dev: bad pty slave count "
1757 o_tty->count, tty_name(o_tty, buf));
1761 if (--tty->count < 0) {
1762 printk(KERN_WARNING "tty_release_dev: bad tty->count (%d) for %s\n",
1763 tty->count, tty_name(tty, buf));
1768 * We've decremented tty->count, so we need to remove this file
1769 * descriptor off the tty->tty_files list; this serves two
1771 * - check_tty_count sees the correct number of file descriptors
1772 * associated with this tty.
1773 * - do_tty_hangup no longer sees this file descriptor as
1774 * something that needs to be handled for hangups.
1777 filp->private_data = NULL;
1780 * Perform some housekeeping before deciding whether to return.
1782 * Set the TTY_CLOSING flag if this was the last open. In the
1783 * case of a pty we may have to wait around for the other side
1784 * to close, and TTY_CLOSING makes sure we can't be reopened.
1787 set_bit(TTY_CLOSING, &tty->flags);
1789 set_bit(TTY_CLOSING, &o_tty->flags);
1792 * If _either_ side is closing, make sure there aren't any
1793 * processes that still think tty or o_tty is their controlling
1796 if (tty_closing || o_tty_closing) {
1797 read_lock(&tasklist_lock);
1798 session_clear_tty(tty->session);
1800 session_clear_tty(o_tty->session);
1801 read_unlock(&tasklist_lock);
1804 mutex_unlock(&tty_mutex);
1806 /* check whether both sides are closing ... */
1807 if (!tty_closing || (o_tty && !o_tty_closing))
1810 #ifdef TTY_DEBUG_HANGUP
1811 printk(KERN_DEBUG "freeing tty structure...");
1814 * Ask the line discipline code to release its structures
1816 tty_ldisc_release(tty, o_tty);
1818 * The release_tty function takes care of the details of clearing
1819 * the slots and preserving the termios structure.
1821 release_tty(tty, idx);
1823 /* Make this pty number available for reallocation */
1825 devpts_kill_index(idx);
1829 * __tty_open - open a tty device
1830 * @inode: inode of device file
1831 * @filp: file pointer to tty
1833 * tty_open and tty_release keep up the tty count that contains the
1834 * number of opens done on a tty. We cannot use the inode-count, as
1835 * different inodes might point to the same tty.
1837 * Open-counting is needed for pty masters, as well as for keeping
1838 * track of serial lines: DTR is dropped when the last close happens.
1839 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1841 * The termios state of a pty is reset on first open so that
1842 * settings don't persist across reuse.
1844 * Locking: tty_mutex protects tty, get_tty_driver and tty_init_dev work.
1845 * tty->count should protect the rest.
1846 * ->siglock protects ->signal/->sighand
1849 static int __tty_open(struct inode *inode, struct file *filp)
1851 struct tty_struct *tty;
1853 struct tty_driver *driver;
1855 dev_t device = inode->i_rdev;
1856 unsigned short saved_flags = filp->f_flags;
1858 nonseekable_open(inode, filp);
1861 noctty = filp->f_flags & O_NOCTTY;
1865 mutex_lock(&tty_mutex);
1867 if (device == MKDEV(TTYAUX_MAJOR, 0)) {
1868 tty = get_current_tty();
1870 mutex_unlock(&tty_mutex);
1873 driver = tty->driver;
1875 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1877 /* FIXME: Should we take a driver reference ? */
1882 if (device == MKDEV(TTY_MAJOR, 0)) {
1883 extern struct tty_driver *console_driver;
1884 driver = console_driver;
1890 if (device == MKDEV(TTYAUX_MAJOR, 1)) {
1891 driver = console_device(&index);
1893 /* Don't let /dev/console block */
1894 filp->f_flags |= O_NONBLOCK;
1898 mutex_unlock(&tty_mutex);
1902 driver = get_tty_driver(device, &index);
1904 mutex_unlock(&tty_mutex);
1908 retval = tty_init_dev(driver, index, &tty, 0);
1909 mutex_unlock(&tty_mutex);
1913 filp->private_data = tty;
1914 file_move(filp, &tty->tty_files);
1915 check_tty_count(tty, "tty_open");
1916 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1917 tty->driver->subtype == PTY_TYPE_MASTER)
1919 #ifdef TTY_DEBUG_HANGUP
1920 printk(KERN_DEBUG "opening %s...", tty->name);
1924 retval = tty->ops->open(tty, filp);
1928 filp->f_flags = saved_flags;
1930 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
1931 !capable(CAP_SYS_ADMIN))
1935 #ifdef TTY_DEBUG_HANGUP
1936 printk(KERN_DEBUG "error %d in opening %s...", retval,
1939 tty_release_dev(filp);
1940 if (retval != -ERESTARTSYS)
1942 if (signal_pending(current))
1946 * Need to reset f_op in case a hangup happened.
1948 if (filp->f_op == &hung_up_tty_fops)
1949 filp->f_op = &tty_fops;
1953 mutex_lock(&tty_mutex);
1954 spin_lock_irq(¤t->sighand->siglock);
1956 current->signal->leader &&
1957 !current->signal->tty &&
1958 tty->session == NULL)
1959 __proc_set_tty(current, tty);
1960 spin_unlock_irq(¤t->sighand->siglock);
1961 mutex_unlock(&tty_mutex);
1965 /* BKL pushdown: scary code avoidance wrapper */
1966 static int tty_open(struct inode *inode, struct file *filp)
1971 ret = __tty_open(inode, filp);
1980 * tty_release - vfs callback for close
1981 * @inode: inode of tty
1982 * @filp: file pointer for handle to tty
1984 * Called the last time each file handle is closed that references
1985 * this tty. There may however be several such references.
1988 * Takes bkl. See tty_release_dev
1991 static int tty_release(struct inode *inode, struct file *filp)
1994 tty_release_dev(filp);
2000 * tty_poll - check tty status
2001 * @filp: file being polled
2002 * @wait: poll wait structures to update
2004 * Call the line discipline polling method to obtain the poll
2005 * status of the device.
2007 * Locking: locks called line discipline but ldisc poll method
2008 * may be re-entered freely by other callers.
2011 static unsigned int tty_poll(struct file *filp, poll_table *wait)
2013 struct tty_struct *tty;
2014 struct tty_ldisc *ld;
2017 tty = (struct tty_struct *)filp->private_data;
2018 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll"))
2021 ld = tty_ldisc_ref_wait(tty);
2023 ret = (ld->ops->poll)(tty, filp, wait);
2024 tty_ldisc_deref(ld);
2028 static int tty_fasync(int fd, struct file *filp, int on)
2030 struct tty_struct *tty;
2031 unsigned long flags;
2035 tty = (struct tty_struct *)filp->private_data;
2036 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
2039 retval = fasync_helper(fd, filp, on, &tty->fasync);
2046 if (!waitqueue_active(&tty->read_wait))
2047 tty->minimum_to_wake = 1;
2048 spin_lock_irqsave(&tty->ctrl_lock, flags);
2051 type = PIDTYPE_PGID;
2053 pid = task_pid(current);
2056 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2057 retval = __f_setown(filp, pid, type, 0);
2061 if (!tty->fasync && !waitqueue_active(&tty->read_wait))
2062 tty->minimum_to_wake = N_TTY_BUF_SIZE;
2071 * tiocsti - fake input character
2072 * @tty: tty to fake input into
2073 * @p: pointer to character
2075 * Fake input to a tty device. Does the necessary locking and
2078 * FIXME: does not honour flow control ??
2081 * Called functions take tty_ldisc_lock
2082 * current->signal->tty check is safe without locks
2084 * FIXME: may race normal receive processing
2087 static int tiocsti(struct tty_struct *tty, char __user *p)
2090 struct tty_ldisc *ld;
2092 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2094 if (get_user(ch, p))
2096 ld = tty_ldisc_ref_wait(tty);
2097 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2098 tty_ldisc_deref(ld);
2103 * tiocgwinsz - implement window query ioctl
2105 * @arg: user buffer for result
2107 * Copies the kernel idea of the window size into the user buffer.
2109 * Locking: tty->termios_mutex is taken to ensure the winsize data
2113 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2117 mutex_lock(&tty->termios_mutex);
2118 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2119 mutex_unlock(&tty->termios_mutex);
2121 return err ? -EFAULT: 0;
2125 * tty_do_resize - resize event
2126 * @tty: tty being resized
2127 * @real_tty: real tty (not the same as tty if using a pty/tty pair)
2128 * @rows: rows (character)
2129 * @cols: cols (character)
2131 * Update the termios variables and send the neccessary signals to
2132 * peform a terminal resize correctly
2135 int tty_do_resize(struct tty_struct *tty, struct tty_struct *real_tty,
2138 struct pid *pgrp, *rpgrp;
2139 unsigned long flags;
2141 /* For a PTY we need to lock the tty side */
2142 mutex_lock(&real_tty->termios_mutex);
2143 if (!memcmp(ws, &real_tty->winsize, sizeof(*ws)))
2145 /* Get the PID values and reference them so we can
2146 avoid holding the tty ctrl lock while sending signals */
2147 spin_lock_irqsave(&tty->ctrl_lock, flags);
2148 pgrp = get_pid(tty->pgrp);
2149 rpgrp = get_pid(real_tty->pgrp);
2150 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2153 kill_pgrp(pgrp, SIGWINCH, 1);
2154 if (rpgrp != pgrp && rpgrp)
2155 kill_pgrp(rpgrp, SIGWINCH, 1);
2161 real_tty->winsize = *ws;
2163 mutex_unlock(&real_tty->termios_mutex);
2168 * tiocswinsz - implement window size set ioctl
2170 * @arg: user buffer for result
2172 * Copies the user idea of the window size to the kernel. Traditionally
2173 * this is just advisory information but for the Linux console it
2174 * actually has driver level meaning and triggers a VC resize.
2177 * Driver dependant. The default do_resize method takes the
2178 * tty termios mutex and ctrl_lock. The console takes its own lock
2179 * then calls into the default method.
2182 static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty,
2183 struct winsize __user *arg)
2185 struct winsize tmp_ws;
2186 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2189 if (tty->ops->resize)
2190 return tty->ops->resize(tty, real_tty, &tmp_ws);
2192 return tty_do_resize(tty, real_tty, &tmp_ws);
2196 * tioccons - allow admin to move logical console
2197 * @file: the file to become console
2199 * Allow the adminstrator to move the redirected console device
2201 * Locking: uses redirect_lock to guard the redirect information
2204 static int tioccons(struct file *file)
2206 if (!capable(CAP_SYS_ADMIN))
2208 if (file->f_op->write == redirected_tty_write) {
2210 spin_lock(&redirect_lock);
2213 spin_unlock(&redirect_lock);
2218 spin_lock(&redirect_lock);
2220 spin_unlock(&redirect_lock);
2225 spin_unlock(&redirect_lock);
2230 * fionbio - non blocking ioctl
2231 * @file: file to set blocking value
2232 * @p: user parameter
2234 * Historical tty interfaces had a blocking control ioctl before
2235 * the generic functionality existed. This piece of history is preserved
2236 * in the expected tty API of posix OS's.
2238 * Locking: none, the open fle handle ensures it won't go away.
2241 static int fionbio(struct file *file, int __user *p)
2245 if (get_user(nonblock, p))
2248 /* file->f_flags is still BKL protected in the fs layer - vomit */
2251 file->f_flags |= O_NONBLOCK;
2253 file->f_flags &= ~O_NONBLOCK;
2259 * tiocsctty - set controlling tty
2260 * @tty: tty structure
2261 * @arg: user argument
2263 * This ioctl is used to manage job control. It permits a session
2264 * leader to set this tty as the controlling tty for the session.
2267 * Takes tty_mutex() to protect tty instance
2268 * Takes tasklist_lock internally to walk sessions
2269 * Takes ->siglock() when updating signal->tty
2272 static int tiocsctty(struct tty_struct *tty, int arg)
2275 if (current->signal->leader && (task_session(current) == tty->session))
2278 mutex_lock(&tty_mutex);
2280 * The process must be a session leader and
2281 * not have a controlling tty already.
2283 if (!current->signal->leader || current->signal->tty) {
2290 * This tty is already the controlling
2291 * tty for another session group!
2293 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2297 read_lock(&tasklist_lock);
2298 session_clear_tty(tty->session);
2299 read_unlock(&tasklist_lock);
2305 proc_set_tty(current, tty);
2307 mutex_unlock(&tty_mutex);
2312 * tty_get_pgrp - return a ref counted pgrp pid
2315 * Returns a refcounted instance of the pid struct for the process
2316 * group controlling the tty.
2319 struct pid *tty_get_pgrp(struct tty_struct *tty)
2321 unsigned long flags;
2324 spin_lock_irqsave(&tty->ctrl_lock, flags);
2325 pgrp = get_pid(tty->pgrp);
2326 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2330 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2333 * tiocgpgrp - get process group
2334 * @tty: tty passed by user
2335 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2338 * Obtain the process group of the tty. If there is no process group
2341 * Locking: none. Reference to current->signal->tty is safe.
2344 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2349 * (tty == real_tty) is a cheap way of
2350 * testing if the tty is NOT a master pty.
2352 if (tty == real_tty && current->signal->tty != real_tty)
2354 pid = tty_get_pgrp(real_tty);
2355 ret = put_user(pid_vnr(pid), p);
2361 * tiocspgrp - attempt to set process group
2362 * @tty: tty passed by user
2363 * @real_tty: tty side device matching tty passed by user
2366 * Set the process group of the tty to the session passed. Only
2367 * permitted where the tty session is our session.
2369 * Locking: RCU, ctrl lock
2372 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2376 int retval = tty_check_change(real_tty);
2377 unsigned long flags;
2383 if (!current->signal->tty ||
2384 (current->signal->tty != real_tty) ||
2385 (real_tty->session != task_session(current)))
2387 if (get_user(pgrp_nr, p))
2392 pgrp = find_vpid(pgrp_nr);
2397 if (session_of_pgrp(pgrp) != task_session(current))
2400 spin_lock_irqsave(&tty->ctrl_lock, flags);
2401 put_pid(real_tty->pgrp);
2402 real_tty->pgrp = get_pid(pgrp);
2403 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2410 * tiocgsid - get session id
2411 * @tty: tty passed by user
2412 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2413 * @p: pointer to returned session id
2415 * Obtain the session id of the tty. If there is no session
2418 * Locking: none. Reference to current->signal->tty is safe.
2421 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2424 * (tty == real_tty) is a cheap way of
2425 * testing if the tty is NOT a master pty.
2427 if (tty == real_tty && current->signal->tty != real_tty)
2429 if (!real_tty->session)
2431 return put_user(pid_vnr(real_tty->session), p);
2435 * tiocsetd - set line discipline
2437 * @p: pointer to user data
2439 * Set the line discipline according to user request.
2441 * Locking: see tty_set_ldisc, this function is just a helper
2444 static int tiocsetd(struct tty_struct *tty, int __user *p)
2449 if (get_user(ldisc, p))
2453 ret = tty_set_ldisc(tty, ldisc);
2460 * send_break - performed time break
2461 * @tty: device to break on
2462 * @duration: timeout in mS
2464 * Perform a timed break on hardware that lacks its own driver level
2465 * timed break functionality.
2468 * atomic_write_lock serializes
2472 static int send_break(struct tty_struct *tty, unsigned int duration)
2476 if (tty->ops->break_ctl == NULL)
2479 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2480 retval = tty->ops->break_ctl(tty, duration);
2482 /* Do the work ourselves */
2483 if (tty_write_lock(tty, 0) < 0)
2485 retval = tty->ops->break_ctl(tty, -1);
2488 if (!signal_pending(current))
2489 msleep_interruptible(duration);
2490 retval = tty->ops->break_ctl(tty, 0);
2492 tty_write_unlock(tty);
2493 if (signal_pending(current))
2500 * tty_tiocmget - get modem status
2502 * @file: user file pointer
2503 * @p: pointer to result
2505 * Obtain the modem status bits from the tty driver if the feature
2506 * is supported. Return -EINVAL if it is not available.
2508 * Locking: none (up to the driver)
2511 static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p)
2513 int retval = -EINVAL;
2515 if (tty->ops->tiocmget) {
2516 retval = tty->ops->tiocmget(tty, file);
2519 retval = put_user(retval, p);
2525 * tty_tiocmset - set modem status
2527 * @file: user file pointer
2528 * @cmd: command - clear bits, set bits or set all
2529 * @p: pointer to desired bits
2531 * Set the modem status bits from the tty driver if the feature
2532 * is supported. Return -EINVAL if it is not available.
2534 * Locking: none (up to the driver)
2537 static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int cmd,
2541 unsigned int set, clear, val;
2543 if (tty->ops->tiocmset == NULL)
2546 retval = get_user(val, p);
2562 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2563 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2564 return tty->ops->tiocmset(tty, file, set, clear);
2568 * Split this up, as gcc can choke on it otherwise..
2570 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2572 struct tty_struct *tty, *real_tty;
2573 void __user *p = (void __user *)arg;
2575 struct tty_ldisc *ld;
2576 struct inode *inode = file->f_dentry->d_inode;
2578 tty = (struct tty_struct *)file->private_data;
2579 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2583 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2584 tty->driver->subtype == PTY_TYPE_MASTER)
2585 real_tty = tty->link;
2589 * Factor out some common prep work
2597 retval = tty_check_change(tty);
2600 if (cmd != TIOCCBRK) {
2601 tty_wait_until_sent(tty, 0);
2602 if (signal_pending(current))
2613 return tiocsti(tty, p);
2615 return tiocgwinsz(real_tty, p);
2617 return tiocswinsz(tty, real_tty, p);
2619 return real_tty != tty ? -EINVAL : tioccons(file);
2621 return fionbio(file, p);
2623 set_bit(TTY_EXCLUSIVE, &tty->flags);
2626 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2629 if (current->signal->tty != tty)
2634 return tiocsctty(tty, arg);
2636 return tiocgpgrp(tty, real_tty, p);
2638 return tiocspgrp(tty, real_tty, p);
2640 return tiocgsid(tty, real_tty, p);
2642 return put_user(tty->ldisc.ops->num, (int __user *)p);
2644 return tiocsetd(tty, p);
2648 case TIOCSBRK: /* Turn break on, unconditionally */
2649 if (tty->ops->break_ctl)
2650 return tty->ops->break_ctl(tty, -1);
2652 case TIOCCBRK: /* Turn break off, unconditionally */
2653 if (tty->ops->break_ctl)
2654 return tty->ops->break_ctl(tty, 0);
2656 case TCSBRK: /* SVID version: non-zero arg --> no break */
2657 /* non-zero arg means wait for all output data
2658 * to be sent (performed above) but don't send break.
2659 * This is used by the tcdrain() termios function.
2662 return send_break(tty, 250);
2664 case TCSBRKP: /* support for POSIX tcsendbreak() */
2665 return send_break(tty, arg ? arg*100 : 250);
2668 return tty_tiocmget(tty, file, p);
2672 return tty_tiocmset(tty, file, cmd, p);
2677 /* flush tty buffer and allow ldisc to process ioctl */
2678 tty_buffer_flush(tty);
2683 if (tty->ops->ioctl) {
2684 retval = (tty->ops->ioctl)(tty, file, cmd, arg);
2685 if (retval != -ENOIOCTLCMD)
2688 ld = tty_ldisc_ref_wait(tty);
2690 if (ld->ops->ioctl) {
2691 retval = ld->ops->ioctl(tty, file, cmd, arg);
2692 if (retval == -ENOIOCTLCMD)
2695 tty_ldisc_deref(ld);
2699 #ifdef CONFIG_COMPAT
2700 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2703 struct inode *inode = file->f_dentry->d_inode;
2704 struct tty_struct *tty = file->private_data;
2705 struct tty_ldisc *ld;
2706 int retval = -ENOIOCTLCMD;
2708 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2711 if (tty->ops->compat_ioctl) {
2712 retval = (tty->ops->compat_ioctl)(tty, file, cmd, arg);
2713 if (retval != -ENOIOCTLCMD)
2717 ld = tty_ldisc_ref_wait(tty);
2718 if (ld->ops->compat_ioctl)
2719 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2720 tty_ldisc_deref(ld);
2727 * This implements the "Secure Attention Key" --- the idea is to
2728 * prevent trojan horses by killing all processes associated with this
2729 * tty when the user hits the "Secure Attention Key". Required for
2730 * super-paranoid applications --- see the Orange Book for more details.
2732 * This code could be nicer; ideally it should send a HUP, wait a few
2733 * seconds, then send a INT, and then a KILL signal. But you then
2734 * have to coordinate with the init process, since all processes associated
2735 * with the current tty must be dead before the new getty is allowed
2738 * Now, if it would be correct ;-/ The current code has a nasty hole -
2739 * it doesn't catch files in flight. We may send the descriptor to ourselves
2740 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2742 * Nasty bug: do_SAK is being called in interrupt context. This can
2743 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2745 void __do_SAK(struct tty_struct *tty)
2750 struct task_struct *g, *p;
2751 struct pid *session;
2754 struct fdtable *fdt;
2758 session = tty->session;
2760 tty_ldisc_flush(tty);
2762 tty_driver_flush_buffer(tty);
2764 read_lock(&tasklist_lock);
2765 /* Kill the entire session */
2766 do_each_pid_task(session, PIDTYPE_SID, p) {
2767 printk(KERN_NOTICE "SAK: killed process %d"
2768 " (%s): task_session_nr(p)==tty->session\n",
2769 task_pid_nr(p), p->comm);
2770 send_sig(SIGKILL, p, 1);
2771 } while_each_pid_task(session, PIDTYPE_SID, p);
2772 /* Now kill any processes that happen to have the
2775 do_each_thread(g, p) {
2776 if (p->signal->tty == tty) {
2777 printk(KERN_NOTICE "SAK: killed process %d"
2778 " (%s): task_session_nr(p)==tty->session\n",
2779 task_pid_nr(p), p->comm);
2780 send_sig(SIGKILL, p, 1);
2786 * We don't take a ref to the file, so we must
2787 * hold ->file_lock instead.
2789 spin_lock(&p->files->file_lock);
2790 fdt = files_fdtable(p->files);
2791 for (i = 0; i < fdt->max_fds; i++) {
2792 filp = fcheck_files(p->files, i);
2795 if (filp->f_op->read == tty_read &&
2796 filp->private_data == tty) {
2797 printk(KERN_NOTICE "SAK: killed process %d"
2798 " (%s): fd#%d opened to the tty\n",
2799 task_pid_nr(p), p->comm, i);
2800 force_sig(SIGKILL, p);
2804 spin_unlock(&p->files->file_lock);
2807 } while_each_thread(g, p);
2808 read_unlock(&tasklist_lock);
2812 static void do_SAK_work(struct work_struct *work)
2814 struct tty_struct *tty =
2815 container_of(work, struct tty_struct, SAK_work);
2820 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2821 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2822 * the values which we write to it will be identical to the values which it
2823 * already has. --akpm
2825 void do_SAK(struct tty_struct *tty)
2829 schedule_work(&tty->SAK_work);
2832 EXPORT_SYMBOL(do_SAK);
2835 * initialize_tty_struct
2836 * @tty: tty to initialize
2838 * This subroutine initializes a tty structure that has been newly
2841 * Locking: none - tty in question must not be exposed at this point
2844 static void initialize_tty_struct(struct tty_struct *tty)
2846 memset(tty, 0, sizeof(struct tty_struct));
2847 kref_init(&tty->kref);
2848 tty->magic = TTY_MAGIC;
2849 tty_ldisc_init(tty);
2850 tty->session = NULL;
2852 tty->overrun_time = jiffies;
2853 tty->buf.head = tty->buf.tail = NULL;
2854 tty_buffer_init(tty);
2855 mutex_init(&tty->termios_mutex);
2856 init_waitqueue_head(&tty->write_wait);
2857 init_waitqueue_head(&tty->read_wait);
2858 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2859 mutex_init(&tty->atomic_read_lock);
2860 mutex_init(&tty->atomic_write_lock);
2861 spin_lock_init(&tty->read_lock);
2862 spin_lock_init(&tty->ctrl_lock);
2863 INIT_LIST_HEAD(&tty->tty_files);
2864 INIT_WORK(&tty->SAK_work, do_SAK_work);
2868 * tty_put_char - write one character to a tty
2872 * Write one byte to the tty using the provided put_char method
2873 * if present. Returns the number of characters successfully output.
2875 * Note: the specific put_char operation in the driver layer may go
2876 * away soon. Don't call it directly, use this method
2879 int tty_put_char(struct tty_struct *tty, unsigned char ch)
2881 if (tty->ops->put_char)
2882 return tty->ops->put_char(tty, ch);
2883 return tty->ops->write(tty, &ch, 1);
2886 EXPORT_SYMBOL_GPL(tty_put_char);
2888 struct class *tty_class;
2891 * tty_register_device - register a tty device
2892 * @driver: the tty driver that describes the tty device
2893 * @index: the index in the tty driver for this tty device
2894 * @device: a struct device that is associated with this tty device.
2895 * This field is optional, if there is no known struct device
2896 * for this tty device it can be set to NULL safely.
2898 * Returns a pointer to the struct device for this tty device
2899 * (or ERR_PTR(-EFOO) on error).
2901 * This call is required to be made to register an individual tty device
2902 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2903 * that bit is not set, this function should not be called by a tty
2909 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
2910 struct device *device)
2913 dev_t dev = MKDEV(driver->major, driver->minor_start) + index;
2915 if (index >= driver->num) {
2916 printk(KERN_ERR "Attempt to register invalid tty line number "
2918 return ERR_PTR(-EINVAL);
2921 if (driver->type == TTY_DRIVER_TYPE_PTY)
2922 pty_line_name(driver, index, name);
2924 tty_line_name(driver, index, name);
2926 return device_create_drvdata(tty_class, device, dev, NULL, name);
2930 * tty_unregister_device - unregister a tty device
2931 * @driver: the tty driver that describes the tty device
2932 * @index: the index in the tty driver for this tty device
2934 * If a tty device is registered with a call to tty_register_device() then
2935 * this function must be called when the tty device is gone.
2940 void tty_unregister_device(struct tty_driver *driver, unsigned index)
2942 device_destroy(tty_class,
2943 MKDEV(driver->major, driver->minor_start) + index);
2946 EXPORT_SYMBOL(tty_register_device);
2947 EXPORT_SYMBOL(tty_unregister_device);
2949 struct tty_driver *alloc_tty_driver(int lines)
2951 struct tty_driver *driver;
2953 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
2955 driver->magic = TTY_DRIVER_MAGIC;
2956 driver->num = lines;
2957 /* later we'll move allocation of tables here */
2962 void put_tty_driver(struct tty_driver *driver)
2967 void tty_set_operations(struct tty_driver *driver,
2968 const struct tty_operations *op)
2973 EXPORT_SYMBOL(alloc_tty_driver);
2974 EXPORT_SYMBOL(put_tty_driver);
2975 EXPORT_SYMBOL(tty_set_operations);
2978 * Called by a tty driver to register itself.
2980 int tty_register_driver(struct tty_driver *driver)
2987 if (driver->flags & TTY_DRIVER_INSTALLED)
2990 if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) {
2991 p = kzalloc(driver->num * 3 * sizeof(void *), GFP_KERNEL);
2996 if (!driver->major) {
2997 error = alloc_chrdev_region(&dev, driver->minor_start,
2998 driver->num, driver->name);
3000 driver->major = MAJOR(dev);
3001 driver->minor_start = MINOR(dev);
3004 dev = MKDEV(driver->major, driver->minor_start);
3005 error = register_chrdev_region(dev, driver->num, driver->name);
3013 driver->ttys = (struct tty_struct **)p;
3014 driver->termios = (struct ktermios **)(p + driver->num);
3015 driver->termios_locked = (struct ktermios **)
3016 (p + driver->num * 2);
3018 driver->ttys = NULL;
3019 driver->termios = NULL;
3020 driver->termios_locked = NULL;
3023 cdev_init(&driver->cdev, &tty_fops);
3024 driver->cdev.owner = driver->owner;
3025 error = cdev_add(&driver->cdev, dev, driver->num);
3027 unregister_chrdev_region(dev, driver->num);
3028 driver->ttys = NULL;
3029 driver->termios = driver->termios_locked = NULL;
3034 mutex_lock(&tty_mutex);
3035 list_add(&driver->tty_drivers, &tty_drivers);
3036 mutex_unlock(&tty_mutex);
3038 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3039 for (i = 0; i < driver->num; i++)
3040 tty_register_device(driver, i, NULL);
3042 proc_tty_register_driver(driver);
3046 EXPORT_SYMBOL(tty_register_driver);
3049 * Called by a tty driver to unregister itself.
3051 int tty_unregister_driver(struct tty_driver *driver)
3054 struct ktermios *tp;
3057 if (driver->refcount)
3060 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3062 mutex_lock(&tty_mutex);
3063 list_del(&driver->tty_drivers);
3064 mutex_unlock(&tty_mutex);
3067 * Free the termios and termios_locked structures because
3068 * we don't want to get memory leaks when modular tty
3069 * drivers are removed from the kernel.
3071 for (i = 0; i < driver->num; i++) {
3072 tp = driver->termios[i];
3074 driver->termios[i] = NULL;
3077 tp = driver->termios_locked[i];
3079 driver->termios_locked[i] = NULL;
3082 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3083 tty_unregister_device(driver, i);
3086 proc_tty_unregister_driver(driver);
3087 driver->ttys = NULL;
3088 driver->termios = driver->termios_locked = NULL;
3090 cdev_del(&driver->cdev);
3093 EXPORT_SYMBOL(tty_unregister_driver);
3095 dev_t tty_devnum(struct tty_struct *tty)
3097 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3099 EXPORT_SYMBOL(tty_devnum);
3101 void proc_clear_tty(struct task_struct *p)
3103 struct tty_struct *tty;
3104 spin_lock_irq(&p->sighand->siglock);
3105 tty = p->signal->tty;
3106 p->signal->tty = NULL;
3107 spin_unlock_irq(&p->sighand->siglock);
3111 /* Called under the sighand lock */
3113 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3116 unsigned long flags;
3117 /* We should not have a session or pgrp to put here but.... */
3118 spin_lock_irqsave(&tty->ctrl_lock, flags);
3119 put_pid(tty->session);
3121 tty->pgrp = get_pid(task_pgrp(tsk));
3122 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3123 tty->session = get_pid(task_session(tsk));
3124 if (tsk->signal->tty) {
3125 printk(KERN_DEBUG "tty not NULL!!\n");
3126 tty_kref_put(tsk->signal->tty);
3129 put_pid(tsk->signal->tty_old_pgrp);
3130 tsk->signal->tty = tty_kref_get(tty);
3131 tsk->signal->tty_old_pgrp = NULL;
3134 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3136 spin_lock_irq(&tsk->sighand->siglock);
3137 __proc_set_tty(tsk, tty);
3138 spin_unlock_irq(&tsk->sighand->siglock);
3141 struct tty_struct *get_current_tty(void)
3143 struct tty_struct *tty;
3144 unsigned long flags;
3146 spin_lock_irqsave(¤t->sighand->siglock, flags);
3147 tty = tty_kref_get(current->signal->tty);
3148 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
3151 EXPORT_SYMBOL_GPL(get_current_tty);
3153 void tty_default_fops(struct file_operations *fops)
3159 * Initialize the console device. This is called *early*, so
3160 * we can't necessarily depend on lots of kernel help here.
3161 * Just do some early initializations, and do the complex setup
3164 void __init console_init(void)
3168 /* Setup the default TTY line discipline. */
3172 * set up the console device so that later boot sequences can
3173 * inform about problems etc..
3175 call = __con_initcall_start;
3176 while (call < __con_initcall_end) {
3182 static int __init tty_class_init(void)
3184 tty_class = class_create(THIS_MODULE, "tty");
3185 if (IS_ERR(tty_class))
3186 return PTR_ERR(tty_class);
3190 postcore_initcall(tty_class_init);
3192 /* 3/2004 jmc: why do these devices exist? */
3194 static struct cdev tty_cdev, console_cdev;
3197 * Ok, now we can initialize the rest of the tty devices and can count
3198 * on memory allocations, interrupts etc..
3200 static int __init tty_init(void)
3202 cdev_init(&tty_cdev, &tty_fops);
3203 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3204 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3205 panic("Couldn't register /dev/tty driver\n");
3206 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL,
3209 cdev_init(&console_cdev, &console_fops);
3210 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3211 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3212 panic("Couldn't register /dev/console driver\n");
3213 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3217 vty_init(&console_fops);
3221 module_init(tty_init);