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;
279 return tty_driver_kref_get(p);
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)) {
323 res = tty_driver_kref_get(p);
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 * tty_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 * tty_driver_lookup_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. Will change once we
1216 * have refcounting in the driver and per driver locking
1218 struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver, int idx)
1220 struct tty_struct *tty;
1222 if (driver->ops->lookup)
1223 return driver->ops->lookup(driver, idx);
1225 tty = driver->ttys[idx];
1230 * tty_driver_install_tty() - install a tty entry in the driver
1231 * @driver: the driver for the tty
1234 * Install a tty object into the driver tables. The tty->index field
1235 * will be set by the time this is called.
1237 * Locking: tty_mutex for now
1239 static int tty_driver_install_tty(struct tty_driver *driver,
1240 struct tty_struct *tty)
1242 if (driver->ops->install)
1243 return driver->ops->install(driver, tty);
1244 driver->ttys[tty->index] = tty;
1249 * tty_driver_remove_tty() - remove a tty from the driver tables
1250 * @driver: the driver for the tty
1251 * @idx: the minor number
1253 * Remvoe a tty object from the driver tables. The tty->index field
1254 * will be set by the time this is called.
1256 * Locking: tty_mutex for now
1258 static void tty_driver_remove_tty(struct tty_driver *driver,
1259 struct tty_struct *tty)
1261 if (driver->ops->remove)
1262 driver->ops->remove(driver, tty);
1264 driver->ttys[tty->index] = NULL;
1268 * tty_reopen() - fast re-open of an open tty
1269 * @tty - the tty to open
1271 * Return 0 on success, -errno on error.
1273 * Locking: tty_mutex must be held from the time the tty was found
1274 * till this open completes.
1276 static int tty_reopen(struct tty_struct *tty)
1278 struct tty_driver *driver = tty->driver;
1280 if (test_bit(TTY_CLOSING, &tty->flags))
1283 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1284 driver->subtype == PTY_TYPE_MASTER) {
1286 * special case for PTY masters: only one open permitted,
1287 * and the slave side open count is incremented as well.
1295 tty->driver = driver; /* N.B. why do this every time?? */
1297 WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
1303 * tty_init_dev - initialise a tty device
1304 * @driver: tty driver we are opening a device on
1305 * @idx: device index
1306 * @ret_tty: returned tty structure
1307 * @first_ok: ok to open a new device (used by ptmx)
1309 * Prepare a tty device. This may not be a "new" clean device but
1310 * could also be an active device. The pty drivers require special
1311 * handling because of this.
1314 * The function is called under the tty_mutex, which
1315 * protects us from the tty struct or driver itself going away.
1317 * On exit the tty device has the line discipline attached and
1318 * a reference count of 1. If a pair was created for pty/tty use
1319 * and the other was a pty master then it too has a reference count of 1.
1321 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1322 * failed open. The new code protects the open with a mutex, so it's
1323 * really quite straightforward. The mutex locking can probably be
1324 * relaxed for the (most common) case of reopening a tty.
1327 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx,
1330 struct tty_struct *tty, *o_tty;
1331 struct ktermios *tp, **tp_loc, *o_tp, **o_tp_loc;
1332 struct ktermios *ltp, **ltp_loc, *o_ltp, **o_ltp_loc;
1335 /* check whether we're reopening an existing tty */
1336 tty = tty_driver_lookup_tty(driver, idx);
1342 retval = tty_reopen(tty);
1344 return ERR_PTR(retval);
1348 /* Check if pty master is being opened multiple times */
1349 if (driver->subtype == PTY_TYPE_MASTER &&
1350 (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok)
1351 return ERR_PTR(-EIO);
1354 * First time open is complex, especially for PTY devices.
1355 * This code guarantees that either everything succeeds and the
1356 * TTY is ready for operation, or else the table slots are vacated
1357 * and the allocated memory released. (Except that the termios
1358 * and locked termios may be retained.)
1361 if (!try_module_get(driver->owner))
1362 return ERR_PTR(-ENODEV);
1368 tty = alloc_tty_struct();
1371 initialize_tty_struct(tty);
1372 tty->driver = driver;
1373 tty->ops = driver->ops;
1375 tty_line_name(driver, idx, tty->name);
1377 if (driver->flags & TTY_DRIVER_DEVPTS_MEM) {
1378 tp_loc = &tty->termios;
1379 ltp_loc = &tty->termios_locked;
1381 tp_loc = &driver->termios[idx];
1382 ltp_loc = &driver->termios_locked[idx];
1386 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1389 *tp = driver->init_termios;
1393 ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL);
1398 if (driver->type == TTY_DRIVER_TYPE_PTY) {
1399 o_tty = alloc_tty_struct();
1402 if (!try_module_get(driver->other->owner)) {
1403 /* This cannot in fact currently happen */
1404 free_tty_struct(o_tty);
1408 initialize_tty_struct(o_tty);
1409 o_tty->driver = driver->other;
1410 o_tty->ops = driver->ops;
1412 tty_line_name(driver->other, idx, o_tty->name);
1414 if (driver->flags & TTY_DRIVER_DEVPTS_MEM) {
1415 o_tp_loc = &o_tty->termios;
1416 o_ltp_loc = &o_tty->termios_locked;
1418 o_tp_loc = &driver->other->termios[idx];
1419 o_ltp_loc = &driver->other->termios_locked[idx];
1423 o_tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1426 *o_tp = driver->other->init_termios;
1430 o_ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL);
1436 * Everything allocated ... set up the o_tty structure.
1438 if (!(driver->other->flags & TTY_DRIVER_DEVPTS_MEM))
1439 driver->other->ttys[idx] = o_tty;
1444 o_tty->termios = *o_tp_loc;
1445 o_tty->termios_locked = *o_ltp_loc;
1446 tty_driver_kref_get(driver->other);
1447 if (driver->subtype == PTY_TYPE_MASTER)
1450 /* Establish the links in both directions */
1456 * All structures have been allocated, so now we install them.
1457 * Failures after this point use release_tty to clean up, so
1458 * there's no need to null out the local pointers.
1465 tty->termios = *tp_loc;
1466 tty->termios_locked = *ltp_loc;
1467 /* Compatibility until drivers always set this */
1468 tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
1469 tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
1470 tty_driver_kref_get(driver);
1473 retval = tty_driver_install_tty(driver, tty);
1475 goto release_mem_out;
1478 * Structures all installed ... call the ldisc open routines.
1479 * If we fail here just call release_tty to clean up. No need
1480 * to decrement the use counts, as release_tty doesn't care.
1483 retval = tty_ldisc_setup(tty, o_tty);
1485 goto release_mem_out;
1488 /* Release locally allocated memory ... nothing placed in slots */
1492 module_put(o_tty->driver->owner);
1493 free_tty_struct(o_tty);
1497 free_tty_struct(tty);
1500 module_put(driver->owner);
1501 return ERR_PTR(-ENOMEM);
1503 /* call the tty release_tty routine to clean out this slot */
1505 if (printk_ratelimit())
1506 printk(KERN_INFO "tty_init_dev: ldisc open failed, "
1507 "clearing slot %d\n", idx);
1508 release_tty(tty, idx);
1509 return ERR_PTR(retval);
1512 void tty_free_termios(struct tty_struct *tty)
1514 struct ktermios *tp;
1515 int idx = tty->index;
1516 /* Kill this flag and push into drivers for locking etc */
1517 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
1518 /* FIXME: Locking on ->termios array */
1520 tty->driver->termios[idx] = NULL;
1523 tp = tty->termios_locked;
1524 tty->driver->termios_locked[idx] = NULL;
1528 EXPORT_SYMBOL(tty_free_termios);
1530 void tty_shutdown(struct tty_struct *tty)
1532 tty_driver_remove_tty(tty->driver, tty);
1533 tty_free_termios(tty);
1535 EXPORT_SYMBOL(tty_shutdown);
1538 * release_one_tty - release tty structure memory
1539 * @kref: kref of tty we are obliterating
1541 * Releases memory associated with a tty structure, and clears out the
1542 * driver table slots. This function is called when a device is no longer
1543 * in use. It also gets called when setup of a device fails.
1546 * tty_mutex - sometimes only
1547 * takes the file list lock internally when working on the list
1548 * of ttys that the driver keeps.
1550 static void release_one_tty(struct kref *kref)
1552 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1553 struct tty_driver *driver = tty->driver;
1555 if (tty->ops->shutdown)
1556 tty->ops->shutdown(tty);
1560 tty_driver_kref_put(driver);
1561 module_put(driver->owner);
1564 list_del_init(&tty->tty_files);
1567 free_tty_struct(tty);
1571 * tty_kref_put - release a tty kref
1574 * Release a reference to a tty device and if need be let the kref
1575 * layer destruct the object for us
1578 void tty_kref_put(struct tty_struct *tty)
1581 kref_put(&tty->kref, release_one_tty);
1583 EXPORT_SYMBOL(tty_kref_put);
1586 * release_tty - release tty structure memory
1588 * Release both @tty and a possible linked partner (think pty pair),
1589 * and decrement the refcount of the backing module.
1592 * tty_mutex - sometimes only
1593 * takes the file list lock internally when working on the list
1594 * of ttys that the driver keeps.
1595 * FIXME: should we require tty_mutex is held here ??
1598 static void release_tty(struct tty_struct *tty, int idx)
1600 /* This should always be true but check for the moment */
1601 WARN_ON(tty->index != idx);
1604 tty_kref_put(tty->link);
1609 * Even releasing the tty structures is a tricky business.. We have
1610 * to be very careful that the structures are all released at the
1611 * same time, as interrupts might otherwise get the wrong pointers.
1613 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1614 * lead to double frees or releasing memory still in use.
1616 void tty_release_dev(struct file *filp)
1618 struct tty_struct *tty, *o_tty;
1619 int pty_master, tty_closing, o_tty_closing, do_sleep;
1624 tty = (struct tty_struct *)filp->private_data;
1625 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode,
1629 check_tty_count(tty, "tty_release_dev");
1631 tty_fasync(-1, filp, 0);
1634 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1635 tty->driver->subtype == PTY_TYPE_MASTER);
1636 devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
1639 #ifdef TTY_PARANOIA_CHECK
1640 if (idx < 0 || idx >= tty->driver->num) {
1641 printk(KERN_DEBUG "tty_release_dev: bad idx when trying to "
1642 "free (%s)\n", tty->name);
1646 if (tty != tty->driver->ttys[idx]) {
1647 printk(KERN_DEBUG "tty_release_dev: driver.table[%d] not tty "
1648 "for (%s)\n", idx, tty->name);
1651 if (tty->termios != tty->driver->termios[idx]) {
1652 printk(KERN_DEBUG "tty_release_dev: driver.termios[%d] not termios "
1657 if (tty->termios_locked != tty->driver->termios_locked[idx]) {
1658 printk(KERN_DEBUG "tty_release_dev: driver.termios_locked[%d] not "
1659 "termios_locked for (%s)\n",
1666 #ifdef TTY_DEBUG_HANGUP
1667 printk(KERN_DEBUG "tty_release_dev of %s (tty count=%d)...",
1668 tty_name(tty, buf), tty->count);
1671 #ifdef TTY_PARANOIA_CHECK
1672 if (tty->driver->other &&
1673 !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
1674 if (o_tty != tty->driver->other->ttys[idx]) {
1675 printk(KERN_DEBUG "tty_release_dev: other->table[%d] "
1676 "not o_tty for (%s)\n",
1680 if (o_tty->termios != tty->driver->other->termios[idx]) {
1681 printk(KERN_DEBUG "tty_release_dev: other->termios[%d] "
1682 "not o_termios for (%s)\n",
1686 if (o_tty->termios_locked !=
1687 tty->driver->other->termios_locked[idx]) {
1688 printk(KERN_DEBUG "tty_release_dev: other->termios_locked["
1689 "%d] not o_termios_locked for (%s)\n",
1693 if (o_tty->link != tty) {
1694 printk(KERN_DEBUG "tty_release_dev: bad pty pointers\n");
1699 if (tty->ops->close)
1700 tty->ops->close(tty, filp);
1703 * Sanity check: if tty->count is going to zero, there shouldn't be
1704 * any waiters on tty->read_wait or tty->write_wait. We test the
1705 * wait queues and kick everyone out _before_ actually starting to
1706 * close. This ensures that we won't block while releasing the tty
1709 * The test for the o_tty closing is necessary, since the master and
1710 * slave sides may close in any order. If the slave side closes out
1711 * first, its count will be one, since the master side holds an open.
1712 * Thus this test wouldn't be triggered at the time the slave closes,
1715 * Note that it's possible for the tty to be opened again while we're
1716 * flushing out waiters. By recalculating the closing flags before
1717 * each iteration we avoid any problems.
1720 /* Guard against races with tty->count changes elsewhere and
1721 opens on /dev/tty */
1723 mutex_lock(&tty_mutex);
1724 tty_closing = tty->count <= 1;
1725 o_tty_closing = o_tty &&
1726 (o_tty->count <= (pty_master ? 1 : 0));
1730 if (waitqueue_active(&tty->read_wait)) {
1731 wake_up(&tty->read_wait);
1734 if (waitqueue_active(&tty->write_wait)) {
1735 wake_up(&tty->write_wait);
1739 if (o_tty_closing) {
1740 if (waitqueue_active(&o_tty->read_wait)) {
1741 wake_up(&o_tty->read_wait);
1744 if (waitqueue_active(&o_tty->write_wait)) {
1745 wake_up(&o_tty->write_wait);
1752 printk(KERN_WARNING "tty_release_dev: %s: read/write wait queue "
1753 "active!\n", tty_name(tty, buf));
1754 mutex_unlock(&tty_mutex);
1759 * The closing flags are now consistent with the open counts on
1760 * both sides, and we've completed the last operation that could
1761 * block, so it's safe to proceed with closing.
1764 if (--o_tty->count < 0) {
1765 printk(KERN_WARNING "tty_release_dev: bad pty slave count "
1767 o_tty->count, tty_name(o_tty, buf));
1771 if (--tty->count < 0) {
1772 printk(KERN_WARNING "tty_release_dev: bad tty->count (%d) for %s\n",
1773 tty->count, tty_name(tty, buf));
1778 * We've decremented tty->count, so we need to remove this file
1779 * descriptor off the tty->tty_files list; this serves two
1781 * - check_tty_count sees the correct number of file descriptors
1782 * associated with this tty.
1783 * - do_tty_hangup no longer sees this file descriptor as
1784 * something that needs to be handled for hangups.
1787 filp->private_data = NULL;
1790 * Perform some housekeeping before deciding whether to return.
1792 * Set the TTY_CLOSING flag if this was the last open. In the
1793 * case of a pty we may have to wait around for the other side
1794 * to close, and TTY_CLOSING makes sure we can't be reopened.
1797 set_bit(TTY_CLOSING, &tty->flags);
1799 set_bit(TTY_CLOSING, &o_tty->flags);
1802 * If _either_ side is closing, make sure there aren't any
1803 * processes that still think tty or o_tty is their controlling
1806 if (tty_closing || o_tty_closing) {
1807 read_lock(&tasklist_lock);
1808 session_clear_tty(tty->session);
1810 session_clear_tty(o_tty->session);
1811 read_unlock(&tasklist_lock);
1814 mutex_unlock(&tty_mutex);
1816 /* check whether both sides are closing ... */
1817 if (!tty_closing || (o_tty && !o_tty_closing))
1820 #ifdef TTY_DEBUG_HANGUP
1821 printk(KERN_DEBUG "freeing tty structure...");
1824 * Ask the line discipline code to release its structures
1826 tty_ldisc_release(tty, o_tty);
1828 * The release_tty function takes care of the details of clearing
1829 * the slots and preserving the termios structure.
1831 release_tty(tty, idx);
1833 /* Make this pty number available for reallocation */
1835 devpts_kill_index(idx);
1839 * __tty_open - open a tty device
1840 * @inode: inode of device file
1841 * @filp: file pointer to tty
1843 * tty_open and tty_release keep up the tty count that contains the
1844 * number of opens done on a tty. We cannot use the inode-count, as
1845 * different inodes might point to the same tty.
1847 * Open-counting is needed for pty masters, as well as for keeping
1848 * track of serial lines: DTR is dropped when the last close happens.
1849 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1851 * The termios state of a pty is reset on first open so that
1852 * settings don't persist across reuse.
1854 * Locking: tty_mutex protects tty, get_tty_driver and tty_init_dev work.
1855 * tty->count should protect the rest.
1856 * ->siglock protects ->signal/->sighand
1859 static int __tty_open(struct inode *inode, struct file *filp)
1861 struct tty_struct *tty;
1863 struct tty_driver *driver;
1865 dev_t device = inode->i_rdev;
1866 unsigned short saved_flags = filp->f_flags;
1868 nonseekable_open(inode, filp);
1871 noctty = filp->f_flags & O_NOCTTY;
1875 mutex_lock(&tty_mutex);
1877 if (device == MKDEV(TTYAUX_MAJOR, 0)) {
1878 tty = get_current_tty();
1880 mutex_unlock(&tty_mutex);
1883 driver = tty_driver_kref_get(tty->driver);
1885 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1887 /* FIXME: Should we take a driver reference ? */
1892 if (device == MKDEV(TTY_MAJOR, 0)) {
1893 extern struct tty_driver *console_driver;
1894 driver = tty_driver_kref_get(console_driver);
1900 if (device == MKDEV(TTYAUX_MAJOR, 1)) {
1901 driver = tty_driver_kref_get(console_device(&index));
1903 /* Don't let /dev/console block */
1904 filp->f_flags |= O_NONBLOCK;
1908 mutex_unlock(&tty_mutex);
1912 driver = get_tty_driver(device, &index);
1914 mutex_unlock(&tty_mutex);
1918 tty = tty_init_dev(driver, index, 0);
1919 mutex_unlock(&tty_mutex);
1920 tty_driver_kref_put(driver);
1922 return PTR_ERR(tty);
1924 filp->private_data = tty;
1925 file_move(filp, &tty->tty_files);
1926 check_tty_count(tty, "tty_open");
1927 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1928 tty->driver->subtype == PTY_TYPE_MASTER)
1930 #ifdef TTY_DEBUG_HANGUP
1931 printk(KERN_DEBUG "opening %s...", tty->name);
1935 retval = tty->ops->open(tty, filp);
1939 filp->f_flags = saved_flags;
1941 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
1942 !capable(CAP_SYS_ADMIN))
1946 #ifdef TTY_DEBUG_HANGUP
1947 printk(KERN_DEBUG "error %d in opening %s...", retval,
1950 tty_release_dev(filp);
1951 if (retval != -ERESTARTSYS)
1953 if (signal_pending(current))
1957 * Need to reset f_op in case a hangup happened.
1959 if (filp->f_op == &hung_up_tty_fops)
1960 filp->f_op = &tty_fops;
1964 mutex_lock(&tty_mutex);
1965 spin_lock_irq(¤t->sighand->siglock);
1967 current->signal->leader &&
1968 !current->signal->tty &&
1969 tty->session == NULL)
1970 __proc_set_tty(current, tty);
1971 spin_unlock_irq(¤t->sighand->siglock);
1972 mutex_unlock(&tty_mutex);
1976 /* BKL pushdown: scary code avoidance wrapper */
1977 static int tty_open(struct inode *inode, struct file *filp)
1982 ret = __tty_open(inode, filp);
1991 * tty_release - vfs callback for close
1992 * @inode: inode of tty
1993 * @filp: file pointer for handle to tty
1995 * Called the last time each file handle is closed that references
1996 * this tty. There may however be several such references.
1999 * Takes bkl. See tty_release_dev
2002 static int tty_release(struct inode *inode, struct file *filp)
2005 tty_release_dev(filp);
2011 * tty_poll - check tty status
2012 * @filp: file being polled
2013 * @wait: poll wait structures to update
2015 * Call the line discipline polling method to obtain the poll
2016 * status of the device.
2018 * Locking: locks called line discipline but ldisc poll method
2019 * may be re-entered freely by other callers.
2022 static unsigned int tty_poll(struct file *filp, poll_table *wait)
2024 struct tty_struct *tty;
2025 struct tty_ldisc *ld;
2028 tty = (struct tty_struct *)filp->private_data;
2029 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll"))
2032 ld = tty_ldisc_ref_wait(tty);
2034 ret = (ld->ops->poll)(tty, filp, wait);
2035 tty_ldisc_deref(ld);
2039 static int tty_fasync(int fd, struct file *filp, int on)
2041 struct tty_struct *tty;
2042 unsigned long flags;
2046 tty = (struct tty_struct *)filp->private_data;
2047 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
2050 retval = fasync_helper(fd, filp, on, &tty->fasync);
2057 if (!waitqueue_active(&tty->read_wait))
2058 tty->minimum_to_wake = 1;
2059 spin_lock_irqsave(&tty->ctrl_lock, flags);
2062 type = PIDTYPE_PGID;
2064 pid = task_pid(current);
2067 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2068 retval = __f_setown(filp, pid, type, 0);
2072 if (!tty->fasync && !waitqueue_active(&tty->read_wait))
2073 tty->minimum_to_wake = N_TTY_BUF_SIZE;
2082 * tiocsti - fake input character
2083 * @tty: tty to fake input into
2084 * @p: pointer to character
2086 * Fake input to a tty device. Does the necessary locking and
2089 * FIXME: does not honour flow control ??
2092 * Called functions take tty_ldisc_lock
2093 * current->signal->tty check is safe without locks
2095 * FIXME: may race normal receive processing
2098 static int tiocsti(struct tty_struct *tty, char __user *p)
2101 struct tty_ldisc *ld;
2103 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2105 if (get_user(ch, p))
2107 ld = tty_ldisc_ref_wait(tty);
2108 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2109 tty_ldisc_deref(ld);
2114 * tiocgwinsz - implement window query ioctl
2116 * @arg: user buffer for result
2118 * Copies the kernel idea of the window size into the user buffer.
2120 * Locking: tty->termios_mutex is taken to ensure the winsize data
2124 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2128 mutex_lock(&tty->termios_mutex);
2129 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2130 mutex_unlock(&tty->termios_mutex);
2132 return err ? -EFAULT: 0;
2136 * tty_do_resize - resize event
2137 * @tty: tty being resized
2138 * @real_tty: real tty (not the same as tty if using a pty/tty pair)
2139 * @rows: rows (character)
2140 * @cols: cols (character)
2142 * Update the termios variables and send the neccessary signals to
2143 * peform a terminal resize correctly
2146 int tty_do_resize(struct tty_struct *tty, struct tty_struct *real_tty,
2149 struct pid *pgrp, *rpgrp;
2150 unsigned long flags;
2152 /* For a PTY we need to lock the tty side */
2153 mutex_lock(&real_tty->termios_mutex);
2154 if (!memcmp(ws, &real_tty->winsize, sizeof(*ws)))
2156 /* Get the PID values and reference them so we can
2157 avoid holding the tty ctrl lock while sending signals */
2158 spin_lock_irqsave(&tty->ctrl_lock, flags);
2159 pgrp = get_pid(tty->pgrp);
2160 rpgrp = get_pid(real_tty->pgrp);
2161 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2164 kill_pgrp(pgrp, SIGWINCH, 1);
2165 if (rpgrp != pgrp && rpgrp)
2166 kill_pgrp(rpgrp, SIGWINCH, 1);
2172 real_tty->winsize = *ws;
2174 mutex_unlock(&real_tty->termios_mutex);
2179 * tiocswinsz - implement window size set ioctl
2181 * @arg: user buffer for result
2183 * Copies the user idea of the window size to the kernel. Traditionally
2184 * this is just advisory information but for the Linux console it
2185 * actually has driver level meaning and triggers a VC resize.
2188 * Driver dependant. The default do_resize method takes the
2189 * tty termios mutex and ctrl_lock. The console takes its own lock
2190 * then calls into the default method.
2193 static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty,
2194 struct winsize __user *arg)
2196 struct winsize tmp_ws;
2197 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2200 if (tty->ops->resize)
2201 return tty->ops->resize(tty, real_tty, &tmp_ws);
2203 return tty_do_resize(tty, real_tty, &tmp_ws);
2207 * tioccons - allow admin to move logical console
2208 * @file: the file to become console
2210 * Allow the adminstrator to move the redirected console device
2212 * Locking: uses redirect_lock to guard the redirect information
2215 static int tioccons(struct file *file)
2217 if (!capable(CAP_SYS_ADMIN))
2219 if (file->f_op->write == redirected_tty_write) {
2221 spin_lock(&redirect_lock);
2224 spin_unlock(&redirect_lock);
2229 spin_lock(&redirect_lock);
2231 spin_unlock(&redirect_lock);
2236 spin_unlock(&redirect_lock);
2241 * fionbio - non blocking ioctl
2242 * @file: file to set blocking value
2243 * @p: user parameter
2245 * Historical tty interfaces had a blocking control ioctl before
2246 * the generic functionality existed. This piece of history is preserved
2247 * in the expected tty API of posix OS's.
2249 * Locking: none, the open fle handle ensures it won't go away.
2252 static int fionbio(struct file *file, int __user *p)
2256 if (get_user(nonblock, p))
2259 /* file->f_flags is still BKL protected in the fs layer - vomit */
2262 file->f_flags |= O_NONBLOCK;
2264 file->f_flags &= ~O_NONBLOCK;
2270 * tiocsctty - set controlling tty
2271 * @tty: tty structure
2272 * @arg: user argument
2274 * This ioctl is used to manage job control. It permits a session
2275 * leader to set this tty as the controlling tty for the session.
2278 * Takes tty_mutex() to protect tty instance
2279 * Takes tasklist_lock internally to walk sessions
2280 * Takes ->siglock() when updating signal->tty
2283 static int tiocsctty(struct tty_struct *tty, int arg)
2286 if (current->signal->leader && (task_session(current) == tty->session))
2289 mutex_lock(&tty_mutex);
2291 * The process must be a session leader and
2292 * not have a controlling tty already.
2294 if (!current->signal->leader || current->signal->tty) {
2301 * This tty is already the controlling
2302 * tty for another session group!
2304 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2308 read_lock(&tasklist_lock);
2309 session_clear_tty(tty->session);
2310 read_unlock(&tasklist_lock);
2316 proc_set_tty(current, tty);
2318 mutex_unlock(&tty_mutex);
2323 * tty_get_pgrp - return a ref counted pgrp pid
2326 * Returns a refcounted instance of the pid struct for the process
2327 * group controlling the tty.
2330 struct pid *tty_get_pgrp(struct tty_struct *tty)
2332 unsigned long flags;
2335 spin_lock_irqsave(&tty->ctrl_lock, flags);
2336 pgrp = get_pid(tty->pgrp);
2337 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2341 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2344 * tiocgpgrp - get process group
2345 * @tty: tty passed by user
2346 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2349 * Obtain the process group of the tty. If there is no process group
2352 * Locking: none. Reference to current->signal->tty is safe.
2355 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2360 * (tty == real_tty) is a cheap way of
2361 * testing if the tty is NOT a master pty.
2363 if (tty == real_tty && current->signal->tty != real_tty)
2365 pid = tty_get_pgrp(real_tty);
2366 ret = put_user(pid_vnr(pid), p);
2372 * tiocspgrp - attempt to set process group
2373 * @tty: tty passed by user
2374 * @real_tty: tty side device matching tty passed by user
2377 * Set the process group of the tty to the session passed. Only
2378 * permitted where the tty session is our session.
2380 * Locking: RCU, ctrl lock
2383 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2387 int retval = tty_check_change(real_tty);
2388 unsigned long flags;
2394 if (!current->signal->tty ||
2395 (current->signal->tty != real_tty) ||
2396 (real_tty->session != task_session(current)))
2398 if (get_user(pgrp_nr, p))
2403 pgrp = find_vpid(pgrp_nr);
2408 if (session_of_pgrp(pgrp) != task_session(current))
2411 spin_lock_irqsave(&tty->ctrl_lock, flags);
2412 put_pid(real_tty->pgrp);
2413 real_tty->pgrp = get_pid(pgrp);
2414 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2421 * tiocgsid - get session id
2422 * @tty: tty passed by user
2423 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2424 * @p: pointer to returned session id
2426 * Obtain the session id of the tty. If there is no session
2429 * Locking: none. Reference to current->signal->tty is safe.
2432 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2435 * (tty == real_tty) is a cheap way of
2436 * testing if the tty is NOT a master pty.
2438 if (tty == real_tty && current->signal->tty != real_tty)
2440 if (!real_tty->session)
2442 return put_user(pid_vnr(real_tty->session), p);
2446 * tiocsetd - set line discipline
2448 * @p: pointer to user data
2450 * Set the line discipline according to user request.
2452 * Locking: see tty_set_ldisc, this function is just a helper
2455 static int tiocsetd(struct tty_struct *tty, int __user *p)
2460 if (get_user(ldisc, p))
2464 ret = tty_set_ldisc(tty, ldisc);
2471 * send_break - performed time break
2472 * @tty: device to break on
2473 * @duration: timeout in mS
2475 * Perform a timed break on hardware that lacks its own driver level
2476 * timed break functionality.
2479 * atomic_write_lock serializes
2483 static int send_break(struct tty_struct *tty, unsigned int duration)
2487 if (tty->ops->break_ctl == NULL)
2490 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2491 retval = tty->ops->break_ctl(tty, duration);
2493 /* Do the work ourselves */
2494 if (tty_write_lock(tty, 0) < 0)
2496 retval = tty->ops->break_ctl(tty, -1);
2499 if (!signal_pending(current))
2500 msleep_interruptible(duration);
2501 retval = tty->ops->break_ctl(tty, 0);
2503 tty_write_unlock(tty);
2504 if (signal_pending(current))
2511 * tty_tiocmget - get modem status
2513 * @file: user file pointer
2514 * @p: pointer to result
2516 * Obtain the modem status bits from the tty driver if the feature
2517 * is supported. Return -EINVAL if it is not available.
2519 * Locking: none (up to the driver)
2522 static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p)
2524 int retval = -EINVAL;
2526 if (tty->ops->tiocmget) {
2527 retval = tty->ops->tiocmget(tty, file);
2530 retval = put_user(retval, p);
2536 * tty_tiocmset - set modem status
2538 * @file: user file pointer
2539 * @cmd: command - clear bits, set bits or set all
2540 * @p: pointer to desired bits
2542 * Set the modem status bits from the tty driver if the feature
2543 * is supported. Return -EINVAL if it is not available.
2545 * Locking: none (up to the driver)
2548 static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int cmd,
2552 unsigned int set, clear, val;
2554 if (tty->ops->tiocmset == NULL)
2557 retval = get_user(val, p);
2573 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2574 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2575 return tty->ops->tiocmset(tty, file, set, clear);
2579 * Split this up, as gcc can choke on it otherwise..
2581 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2583 struct tty_struct *tty, *real_tty;
2584 void __user *p = (void __user *)arg;
2586 struct tty_ldisc *ld;
2587 struct inode *inode = file->f_dentry->d_inode;
2589 tty = (struct tty_struct *)file->private_data;
2590 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2594 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2595 tty->driver->subtype == PTY_TYPE_MASTER)
2596 real_tty = tty->link;
2600 * Factor out some common prep work
2608 retval = tty_check_change(tty);
2611 if (cmd != TIOCCBRK) {
2612 tty_wait_until_sent(tty, 0);
2613 if (signal_pending(current))
2624 return tiocsti(tty, p);
2626 return tiocgwinsz(real_tty, p);
2628 return tiocswinsz(tty, real_tty, p);
2630 return real_tty != tty ? -EINVAL : tioccons(file);
2632 return fionbio(file, p);
2634 set_bit(TTY_EXCLUSIVE, &tty->flags);
2637 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2640 if (current->signal->tty != tty)
2645 return tiocsctty(tty, arg);
2647 return tiocgpgrp(tty, real_tty, p);
2649 return tiocspgrp(tty, real_tty, p);
2651 return tiocgsid(tty, real_tty, p);
2653 return put_user(tty->ldisc.ops->num, (int __user *)p);
2655 return tiocsetd(tty, p);
2659 case TIOCSBRK: /* Turn break on, unconditionally */
2660 if (tty->ops->break_ctl)
2661 return tty->ops->break_ctl(tty, -1);
2663 case TIOCCBRK: /* Turn break off, unconditionally */
2664 if (tty->ops->break_ctl)
2665 return tty->ops->break_ctl(tty, 0);
2667 case TCSBRK: /* SVID version: non-zero arg --> no break */
2668 /* non-zero arg means wait for all output data
2669 * to be sent (performed above) but don't send break.
2670 * This is used by the tcdrain() termios function.
2673 return send_break(tty, 250);
2675 case TCSBRKP: /* support for POSIX tcsendbreak() */
2676 return send_break(tty, arg ? arg*100 : 250);
2679 return tty_tiocmget(tty, file, p);
2683 return tty_tiocmset(tty, file, cmd, p);
2688 /* flush tty buffer and allow ldisc to process ioctl */
2689 tty_buffer_flush(tty);
2694 if (tty->ops->ioctl) {
2695 retval = (tty->ops->ioctl)(tty, file, cmd, arg);
2696 if (retval != -ENOIOCTLCMD)
2699 ld = tty_ldisc_ref_wait(tty);
2701 if (ld->ops->ioctl) {
2702 retval = ld->ops->ioctl(tty, file, cmd, arg);
2703 if (retval == -ENOIOCTLCMD)
2706 tty_ldisc_deref(ld);
2710 #ifdef CONFIG_COMPAT
2711 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2714 struct inode *inode = file->f_dentry->d_inode;
2715 struct tty_struct *tty = file->private_data;
2716 struct tty_ldisc *ld;
2717 int retval = -ENOIOCTLCMD;
2719 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2722 if (tty->ops->compat_ioctl) {
2723 retval = (tty->ops->compat_ioctl)(tty, file, cmd, arg);
2724 if (retval != -ENOIOCTLCMD)
2728 ld = tty_ldisc_ref_wait(tty);
2729 if (ld->ops->compat_ioctl)
2730 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2731 tty_ldisc_deref(ld);
2738 * This implements the "Secure Attention Key" --- the idea is to
2739 * prevent trojan horses by killing all processes associated with this
2740 * tty when the user hits the "Secure Attention Key". Required for
2741 * super-paranoid applications --- see the Orange Book for more details.
2743 * This code could be nicer; ideally it should send a HUP, wait a few
2744 * seconds, then send a INT, and then a KILL signal. But you then
2745 * have to coordinate with the init process, since all processes associated
2746 * with the current tty must be dead before the new getty is allowed
2749 * Now, if it would be correct ;-/ The current code has a nasty hole -
2750 * it doesn't catch files in flight. We may send the descriptor to ourselves
2751 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2753 * Nasty bug: do_SAK is being called in interrupt context. This can
2754 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2756 void __do_SAK(struct tty_struct *tty)
2761 struct task_struct *g, *p;
2762 struct pid *session;
2765 struct fdtable *fdt;
2769 session = tty->session;
2771 tty_ldisc_flush(tty);
2773 tty_driver_flush_buffer(tty);
2775 read_lock(&tasklist_lock);
2776 /* Kill the entire session */
2777 do_each_pid_task(session, PIDTYPE_SID, p) {
2778 printk(KERN_NOTICE "SAK: killed process %d"
2779 " (%s): task_session_nr(p)==tty->session\n",
2780 task_pid_nr(p), p->comm);
2781 send_sig(SIGKILL, p, 1);
2782 } while_each_pid_task(session, PIDTYPE_SID, p);
2783 /* Now kill any processes that happen to have the
2786 do_each_thread(g, p) {
2787 if (p->signal->tty == tty) {
2788 printk(KERN_NOTICE "SAK: killed process %d"
2789 " (%s): task_session_nr(p)==tty->session\n",
2790 task_pid_nr(p), p->comm);
2791 send_sig(SIGKILL, p, 1);
2797 * We don't take a ref to the file, so we must
2798 * hold ->file_lock instead.
2800 spin_lock(&p->files->file_lock);
2801 fdt = files_fdtable(p->files);
2802 for (i = 0; i < fdt->max_fds; i++) {
2803 filp = fcheck_files(p->files, i);
2806 if (filp->f_op->read == tty_read &&
2807 filp->private_data == tty) {
2808 printk(KERN_NOTICE "SAK: killed process %d"
2809 " (%s): fd#%d opened to the tty\n",
2810 task_pid_nr(p), p->comm, i);
2811 force_sig(SIGKILL, p);
2815 spin_unlock(&p->files->file_lock);
2818 } while_each_thread(g, p);
2819 read_unlock(&tasklist_lock);
2823 static void do_SAK_work(struct work_struct *work)
2825 struct tty_struct *tty =
2826 container_of(work, struct tty_struct, SAK_work);
2831 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2832 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2833 * the values which we write to it will be identical to the values which it
2834 * already has. --akpm
2836 void do_SAK(struct tty_struct *tty)
2840 schedule_work(&tty->SAK_work);
2843 EXPORT_SYMBOL(do_SAK);
2846 * initialize_tty_struct
2847 * @tty: tty to initialize
2849 * This subroutine initializes a tty structure that has been newly
2852 * Locking: none - tty in question must not be exposed at this point
2855 static void initialize_tty_struct(struct tty_struct *tty)
2857 memset(tty, 0, sizeof(struct tty_struct));
2858 kref_init(&tty->kref);
2859 tty->magic = TTY_MAGIC;
2860 tty_ldisc_init(tty);
2861 tty->session = NULL;
2863 tty->overrun_time = jiffies;
2864 tty->buf.head = tty->buf.tail = NULL;
2865 tty_buffer_init(tty);
2866 mutex_init(&tty->termios_mutex);
2867 init_waitqueue_head(&tty->write_wait);
2868 init_waitqueue_head(&tty->read_wait);
2869 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2870 mutex_init(&tty->atomic_read_lock);
2871 mutex_init(&tty->atomic_write_lock);
2872 spin_lock_init(&tty->read_lock);
2873 spin_lock_init(&tty->ctrl_lock);
2874 INIT_LIST_HEAD(&tty->tty_files);
2875 INIT_WORK(&tty->SAK_work, do_SAK_work);
2879 * tty_put_char - write one character to a tty
2883 * Write one byte to the tty using the provided put_char method
2884 * if present. Returns the number of characters successfully output.
2886 * Note: the specific put_char operation in the driver layer may go
2887 * away soon. Don't call it directly, use this method
2890 int tty_put_char(struct tty_struct *tty, unsigned char ch)
2892 if (tty->ops->put_char)
2893 return tty->ops->put_char(tty, ch);
2894 return tty->ops->write(tty, &ch, 1);
2896 EXPORT_SYMBOL_GPL(tty_put_char);
2898 struct class *tty_class;
2901 * tty_register_device - register a tty device
2902 * @driver: the tty driver that describes the tty device
2903 * @index: the index in the tty driver for this tty device
2904 * @device: a struct device that is associated with this tty device.
2905 * This field is optional, if there is no known struct device
2906 * for this tty device it can be set to NULL safely.
2908 * Returns a pointer to the struct device for this tty device
2909 * (or ERR_PTR(-EFOO) on error).
2911 * This call is required to be made to register an individual tty device
2912 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2913 * that bit is not set, this function should not be called by a tty
2919 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
2920 struct device *device)
2923 dev_t dev = MKDEV(driver->major, driver->minor_start) + index;
2925 if (index >= driver->num) {
2926 printk(KERN_ERR "Attempt to register invalid tty line number "
2928 return ERR_PTR(-EINVAL);
2931 if (driver->type == TTY_DRIVER_TYPE_PTY)
2932 pty_line_name(driver, index, name);
2934 tty_line_name(driver, index, name);
2936 return device_create_drvdata(tty_class, device, dev, NULL, name);
2938 EXPORT_SYMBOL(tty_register_device);
2941 * tty_unregister_device - unregister a tty device
2942 * @driver: the tty driver that describes the tty device
2943 * @index: the index in the tty driver for this tty device
2945 * If a tty device is registered with a call to tty_register_device() then
2946 * this function must be called when the tty device is gone.
2951 void tty_unregister_device(struct tty_driver *driver, unsigned index)
2953 device_destroy(tty_class,
2954 MKDEV(driver->major, driver->minor_start) + index);
2956 EXPORT_SYMBOL(tty_unregister_device);
2958 struct tty_driver *alloc_tty_driver(int lines)
2960 struct tty_driver *driver;
2962 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
2964 kref_init(&driver->kref);
2965 driver->magic = TTY_DRIVER_MAGIC;
2966 driver->num = lines;
2967 /* later we'll move allocation of tables here */
2971 EXPORT_SYMBOL(alloc_tty_driver);
2973 static void destruct_tty_driver(struct kref *kref)
2975 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
2977 struct ktermios *tp;
2980 if (driver->flags & TTY_DRIVER_INSTALLED) {
2982 * Free the termios and termios_locked structures because
2983 * we don't want to get memory leaks when modular tty
2984 * drivers are removed from the kernel.
2986 for (i = 0; i < driver->num; i++) {
2987 tp = driver->termios[i];
2989 driver->termios[i] = NULL;
2992 tp = driver->termios_locked[i];
2994 driver->termios_locked[i] = NULL;
2997 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
2998 tty_unregister_device(driver, i);
3001 proc_tty_unregister_driver(driver);
3002 driver->ttys = NULL;
3003 driver->termios = driver->termios_locked = NULL;
3005 cdev_del(&driver->cdev);
3010 void tty_driver_kref_put(struct tty_driver *driver)
3012 kref_put(&driver->kref, destruct_tty_driver);
3014 EXPORT_SYMBOL(tty_driver_kref_put);
3016 void tty_set_operations(struct tty_driver *driver,
3017 const struct tty_operations *op)
3021 EXPORT_SYMBOL(tty_set_operations);
3023 void put_tty_driver(struct tty_driver *d)
3025 tty_driver_kref_put(d);
3027 EXPORT_SYMBOL(put_tty_driver);
3030 * Called by a tty driver to register itself.
3032 int tty_register_driver(struct tty_driver *driver)
3039 if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) {
3040 p = kzalloc(driver->num * 3 * sizeof(void *), GFP_KERNEL);
3045 if (!driver->major) {
3046 error = alloc_chrdev_region(&dev, driver->minor_start,
3047 driver->num, driver->name);
3049 driver->major = MAJOR(dev);
3050 driver->minor_start = MINOR(dev);
3053 dev = MKDEV(driver->major, driver->minor_start);
3054 error = register_chrdev_region(dev, driver->num, driver->name);
3062 driver->ttys = (struct tty_struct **)p;
3063 driver->termios = (struct ktermios **)(p + driver->num);
3064 driver->termios_locked = (struct ktermios **)
3065 (p + driver->num * 2);
3067 driver->ttys = NULL;
3068 driver->termios = NULL;
3069 driver->termios_locked = NULL;
3072 cdev_init(&driver->cdev, &tty_fops);
3073 driver->cdev.owner = driver->owner;
3074 error = cdev_add(&driver->cdev, dev, driver->num);
3076 unregister_chrdev_region(dev, driver->num);
3077 driver->ttys = NULL;
3078 driver->termios = driver->termios_locked = NULL;
3083 mutex_lock(&tty_mutex);
3084 list_add(&driver->tty_drivers, &tty_drivers);
3085 mutex_unlock(&tty_mutex);
3087 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3088 for (i = 0; i < driver->num; i++)
3089 tty_register_device(driver, i, NULL);
3091 proc_tty_register_driver(driver);
3092 driver->flags |= TTY_DRIVER_INSTALLED;
3096 EXPORT_SYMBOL(tty_register_driver);
3099 * Called by a tty driver to unregister itself.
3101 int tty_unregister_driver(struct tty_driver *driver)
3105 if (driver->refcount)
3108 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3110 mutex_lock(&tty_mutex);
3111 list_del(&driver->tty_drivers);
3112 mutex_unlock(&tty_mutex);
3116 EXPORT_SYMBOL(tty_unregister_driver);
3118 dev_t tty_devnum(struct tty_struct *tty)
3120 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3122 EXPORT_SYMBOL(tty_devnum);
3124 void proc_clear_tty(struct task_struct *p)
3126 struct tty_struct *tty;
3127 spin_lock_irq(&p->sighand->siglock);
3128 tty = p->signal->tty;
3129 p->signal->tty = NULL;
3130 spin_unlock_irq(&p->sighand->siglock);
3134 /* Called under the sighand lock */
3136 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3139 unsigned long flags;
3140 /* We should not have a session or pgrp to put here but.... */
3141 spin_lock_irqsave(&tty->ctrl_lock, flags);
3142 put_pid(tty->session);
3144 tty->pgrp = get_pid(task_pgrp(tsk));
3145 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3146 tty->session = get_pid(task_session(tsk));
3147 if (tsk->signal->tty) {
3148 printk(KERN_DEBUG "tty not NULL!!\n");
3149 tty_kref_put(tsk->signal->tty);
3152 put_pid(tsk->signal->tty_old_pgrp);
3153 tsk->signal->tty = tty_kref_get(tty);
3154 tsk->signal->tty_old_pgrp = NULL;
3157 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3159 spin_lock_irq(&tsk->sighand->siglock);
3160 __proc_set_tty(tsk, tty);
3161 spin_unlock_irq(&tsk->sighand->siglock);
3164 struct tty_struct *get_current_tty(void)
3166 struct tty_struct *tty;
3167 unsigned long flags;
3169 spin_lock_irqsave(¤t->sighand->siglock, flags);
3170 tty = tty_kref_get(current->signal->tty);
3171 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
3174 EXPORT_SYMBOL_GPL(get_current_tty);
3176 void tty_default_fops(struct file_operations *fops)
3182 * Initialize the console device. This is called *early*, so
3183 * we can't necessarily depend on lots of kernel help here.
3184 * Just do some early initializations, and do the complex setup
3187 void __init console_init(void)
3191 /* Setup the default TTY line discipline. */
3195 * set up the console device so that later boot sequences can
3196 * inform about problems etc..
3198 call = __con_initcall_start;
3199 while (call < __con_initcall_end) {
3205 static int __init tty_class_init(void)
3207 tty_class = class_create(THIS_MODULE, "tty");
3208 if (IS_ERR(tty_class))
3209 return PTR_ERR(tty_class);
3213 postcore_initcall(tty_class_init);
3215 /* 3/2004 jmc: why do these devices exist? */
3217 static struct cdev tty_cdev, console_cdev;
3220 * Ok, now we can initialize the rest of the tty devices and can count
3221 * on memory allocations, interrupts etc..
3223 static int __init tty_init(void)
3225 cdev_init(&tty_cdev, &tty_fops);
3226 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3227 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3228 panic("Couldn't register /dev/tty driver\n");
3229 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL,
3232 cdev_init(&console_cdev, &console_fops);
3233 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3234 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3235 panic("Couldn't register /dev/console driver\n");
3236 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3240 vty_init(&console_fops);
3244 module_init(tty_init);