2 * linux/drivers/char/tty_io.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
8 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
9 * or rs-channels. It also implements echoing, cooked mode etc.
11 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
13 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
14 * tty_struct and tty_queue structures. Previously there was an array
15 * of 256 tty_struct's which was statically allocated, and the
16 * tty_queue structures were allocated at boot time. Both are now
17 * dynamically allocated only when the tty is open.
19 * Also restructured routines so that there is more of a separation
20 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
21 * the low-level tty routines (serial.c, pty.c, console.c). This
22 * makes for cleaner and more compact code. -TYT, 9/17/92
24 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
25 * which can be dynamically activated and de-activated by the line
26 * discipline handling modules (like SLIP).
28 * NOTE: pay no attention to the line discipline code (yet); its
29 * interface is still subject to change in this version...
32 * Added functionality to the OPOST tty handling. No delays, but all
33 * other bits should be there.
34 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
36 * Rewrote canonical mode and added more termios flags.
37 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
39 * Reorganized FASYNC support so mouse code can share it.
40 * -- ctm@ardi.com, 9Sep95
42 * New TIOCLINUX variants added.
43 * -- mj@k332.feld.cvut.cz, 19-Nov-95
45 * Restrict vt switching via ioctl()
46 * -- grif@cs.ucr.edu, 5-Dec-95
48 * Move console and virtual terminal code to more appropriate files,
49 * implement CONFIG_VT and generalize console device interface.
50 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
52 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
53 * -- Bill Hawes <whawes@star.net>, June 97
55 * Added devfs support.
56 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
58 * Added support for a Unix98-style ptmx device.
59 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
61 * Reduced memory usage for older ARM systems
62 * -- Russell King <rmk@arm.linux.org.uk>
64 * Move do_SAK() into process context. Less stack use in devfs functions.
65 * alloc_tty_struct() always uses kmalloc()
66 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
69 #include <linux/types.h>
70 #include <linux/major.h>
71 #include <linux/errno.h>
72 #include <linux/signal.h>
73 #include <linux/fcntl.h>
74 #include <linux/sched.h>
75 #include <linux/interrupt.h>
76 #include <linux/tty.h>
77 #include <linux/tty_driver.h>
78 #include <linux/tty_flip.h>
79 #include <linux/devpts_fs.h>
80 #include <linux/file.h>
81 #include <linux/fdtable.h>
82 #include <linux/console.h>
83 #include <linux/timer.h>
84 #include <linux/ctype.h>
87 #include <linux/string.h>
88 #include <linux/slab.h>
89 #include <linux/poll.h>
90 #include <linux/proc_fs.h>
91 #include <linux/init.h>
92 #include <linux/module.h>
93 #include <linux/smp_lock.h>
94 #include <linux/device.h>
95 #include <linux/wait.h>
96 #include <linux/bitops.h>
97 #include <linux/delay.h>
98 #include <linux/seq_file.h>
100 #include <linux/uaccess.h>
101 #include <asm/system.h>
103 #include <linux/kbd_kern.h>
104 #include <linux/vt_kern.h>
105 #include <linux/selection.h>
107 #include <linux/kmod.h>
108 #include <linux/nsproxy.h>
110 #undef TTY_DEBUG_HANGUP
112 #define TTY_PARANOIA_CHECK 1
113 #define CHECK_TTY_COUNT 1
115 struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
116 .c_iflag = ICRNL | IXON,
117 .c_oflag = OPOST | ONLCR,
118 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
119 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
120 ECHOCTL | ECHOKE | IEXTEN,
126 EXPORT_SYMBOL(tty_std_termios);
128 /* This list gets poked at by procfs and various bits of boot up code. This
129 could do with some rationalisation such as pulling the tty proc function
132 LIST_HEAD(tty_drivers); /* linked list of tty drivers */
134 /* Mutex to protect creating and releasing a tty. This is shared with
135 vt.c for deeply disgusting hack reasons */
136 DEFINE_MUTEX(tty_mutex);
137 EXPORT_SYMBOL(tty_mutex);
139 static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
140 static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
141 ssize_t redirected_tty_write(struct file *, const char __user *,
143 static unsigned int tty_poll(struct file *, poll_table *);
144 static int tty_open(struct inode *, struct file *);
145 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
147 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
150 #define tty_compat_ioctl NULL
152 static int tty_fasync(int fd, struct file *filp, int on);
153 static void release_tty(struct tty_struct *tty, int idx);
154 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
155 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
158 * alloc_tty_struct - allocate a tty object
160 * Return a new empty tty structure. The data fields have not
161 * been initialized in any way but has been zeroed
166 struct tty_struct *alloc_tty_struct(void)
168 return kzalloc(sizeof(struct tty_struct), GFP_KERNEL);
172 * free_tty_struct - free a disused tty
173 * @tty: tty struct to free
175 * Free the write buffers, tty queue and tty memory itself.
177 * Locking: none. Must be called after tty is definitely unused
180 void free_tty_struct(struct tty_struct *tty)
182 kfree(tty->write_buf);
183 tty_buffer_free_all(tty);
187 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
190 * tty_name - return tty naming
191 * @tty: tty structure
192 * @buf: buffer for output
194 * Convert a tty structure into a name. The name reflects the kernel
195 * naming policy and if udev is in use may not reflect user space
200 char *tty_name(struct tty_struct *tty, char *buf)
202 if (!tty) /* Hmm. NULL pointer. That's fun. */
203 strcpy(buf, "NULL tty");
205 strcpy(buf, tty->name);
209 EXPORT_SYMBOL(tty_name);
211 int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
214 #ifdef TTY_PARANOIA_CHECK
217 "null TTY for (%d:%d) in %s\n",
218 imajor(inode), iminor(inode), routine);
221 if (tty->magic != TTY_MAGIC) {
223 "bad magic number for tty struct (%d:%d) in %s\n",
224 imajor(inode), iminor(inode), routine);
231 static int check_tty_count(struct tty_struct *tty, const char *routine)
233 #ifdef CHECK_TTY_COUNT
238 list_for_each(p, &tty->tty_files) {
242 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
243 tty->driver->subtype == PTY_TYPE_SLAVE &&
244 tty->link && tty->link->count)
246 if (tty->count != count) {
247 printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) "
248 "!= #fd's(%d) in %s\n",
249 tty->name, tty->count, count, routine);
257 * get_tty_driver - find device of a tty
258 * @dev_t: device identifier
259 * @index: returns the index of the tty
261 * This routine returns a tty driver structure, given a device number
262 * and also passes back the index number.
264 * Locking: caller must hold tty_mutex
267 static struct tty_driver *get_tty_driver(dev_t device, int *index)
269 struct tty_driver *p;
271 list_for_each_entry(p, &tty_drivers, tty_drivers) {
272 dev_t base = MKDEV(p->major, p->minor_start);
273 if (device < base || device >= base + p->num)
275 *index = device - base;
276 return tty_driver_kref_get(p);
281 #ifdef CONFIG_CONSOLE_POLL
284 * tty_find_polling_driver - find device of a polled tty
285 * @name: name string to match
286 * @line: pointer to resulting tty line nr
288 * This routine returns a tty driver structure, given a name
289 * and the condition that the tty driver is capable of polled
292 struct tty_driver *tty_find_polling_driver(char *name, int *line)
294 struct tty_driver *p, *res = NULL;
299 for (str = name; *str; str++)
300 if ((*str >= '0' && *str <= '9') || *str == ',')
306 tty_line = simple_strtoul(str, &str, 10);
308 mutex_lock(&tty_mutex);
309 /* Search through the tty devices to look for a match */
310 list_for_each_entry(p, &tty_drivers, tty_drivers) {
311 if (strncmp(name, p->name, len) != 0)
319 if (tty_line >= 0 && tty_line <= p->num && p->ops &&
320 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
321 res = tty_driver_kref_get(p);
326 mutex_unlock(&tty_mutex);
330 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
334 * tty_check_change - check for POSIX terminal changes
337 * If we try to write to, or set the state of, a terminal and we're
338 * not in the foreground, send a SIGTTOU. If the signal is blocked or
339 * ignored, go ahead and perform the operation. (POSIX 7.2)
344 int tty_check_change(struct tty_struct *tty)
349 if (current->signal->tty != tty)
352 spin_lock_irqsave(&tty->ctrl_lock, flags);
355 printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
358 if (task_pgrp(current) == tty->pgrp)
360 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
361 if (is_ignored(SIGTTOU))
363 if (is_current_pgrp_orphaned()) {
367 kill_pgrp(task_pgrp(current), SIGTTOU, 1);
368 set_thread_flag(TIF_SIGPENDING);
373 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
377 EXPORT_SYMBOL(tty_check_change);
379 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
380 size_t count, loff_t *ppos)
385 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
386 size_t count, loff_t *ppos)
391 /* No kernel lock held - none needed ;) */
392 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
394 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
397 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
400 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
403 static long hung_up_tty_compat_ioctl(struct file *file,
404 unsigned int cmd, unsigned long arg)
406 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
409 static const struct file_operations tty_fops = {
414 .unlocked_ioctl = tty_ioctl,
415 .compat_ioctl = tty_compat_ioctl,
417 .release = tty_release,
418 .fasync = tty_fasync,
421 static const struct file_operations console_fops = {
424 .write = redirected_tty_write,
426 .unlocked_ioctl = tty_ioctl,
427 .compat_ioctl = tty_compat_ioctl,
429 .release = tty_release,
430 .fasync = tty_fasync,
433 static const struct file_operations hung_up_tty_fops = {
435 .read = hung_up_tty_read,
436 .write = hung_up_tty_write,
437 .poll = hung_up_tty_poll,
438 .unlocked_ioctl = hung_up_tty_ioctl,
439 .compat_ioctl = hung_up_tty_compat_ioctl,
440 .release = tty_release,
443 static DEFINE_SPINLOCK(redirect_lock);
444 static struct file *redirect;
447 * tty_wakeup - request more data
450 * Internal and external helper for wakeups of tty. This function
451 * informs the line discipline if present that the driver is ready
452 * to receive more output data.
455 void tty_wakeup(struct tty_struct *tty)
457 struct tty_ldisc *ld;
459 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
460 ld = tty_ldisc_ref(tty);
462 if (ld->ops->write_wakeup)
463 ld->ops->write_wakeup(tty);
467 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
470 EXPORT_SYMBOL_GPL(tty_wakeup);
473 * do_tty_hangup - actual handler for hangup events
476 * This can be called by the "eventd" kernel thread. That is process
477 * synchronous but doesn't hold any locks, so we need to make sure we
478 * have the appropriate locks for what we're doing.
480 * The hangup event clears any pending redirections onto the hung up
481 * device. It ensures future writes will error and it does the needed
482 * line discipline hangup and signal delivery. The tty object itself
487 * redirect lock for undoing redirection
488 * file list lock for manipulating list of ttys
489 * tty_ldisc_lock from called functions
490 * termios_mutex resetting termios data
491 * tasklist_lock to walk task list for hangup event
492 * ->siglock to protect ->signal/->sighand
494 static void do_tty_hangup(struct work_struct *work)
496 struct tty_struct *tty =
497 container_of(work, struct tty_struct, hangup_work);
498 struct file *cons_filp = NULL;
499 struct file *filp, *f = NULL;
500 struct task_struct *p;
501 int closecount = 0, n;
509 spin_lock(&redirect_lock);
510 if (redirect && redirect->private_data == tty) {
514 spin_unlock(&redirect_lock);
516 /* inuse_filps is protected by the single kernel lock */
518 check_tty_count(tty, "do_tty_hangup");
521 /* This breaks for file handles being sent over AF_UNIX sockets ? */
522 list_for_each_entry(filp, &tty->tty_files, f_u.fu_list) {
523 if (filp->f_op->write == redirected_tty_write)
525 if (filp->f_op->write != tty_write)
528 tty_fasync(-1, filp, 0); /* can't block */
529 filp->f_op = &hung_up_tty_fops;
533 tty_ldisc_hangup(tty);
535 read_lock(&tasklist_lock);
537 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
538 spin_lock_irq(&p->sighand->siglock);
539 if (p->signal->tty == tty) {
540 p->signal->tty = NULL;
541 /* We defer the dereferences outside fo
545 if (!p->signal->leader) {
546 spin_unlock_irq(&p->sighand->siglock);
549 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
550 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
551 put_pid(p->signal->tty_old_pgrp); /* A noop */
552 spin_lock_irqsave(&tty->ctrl_lock, flags);
554 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
555 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
556 spin_unlock_irq(&p->sighand->siglock);
557 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
559 read_unlock(&tasklist_lock);
561 spin_lock_irqsave(&tty->ctrl_lock, flags);
562 clear_bit(TTY_THROTTLED, &tty->flags);
563 clear_bit(TTY_PUSH, &tty->flags);
564 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
565 put_pid(tty->session);
569 tty->ctrl_status = 0;
570 set_bit(TTY_HUPPED, &tty->flags);
571 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
573 /* Account for the p->signal references we killed */
578 * If one of the devices matches a console pointer, we
579 * cannot just call hangup() because that will cause
580 * tty->count and state->count to go out of sync.
581 * So we just call close() the right number of times.
585 for (n = 0; n < closecount; n++)
586 tty->ops->close(tty, cons_filp);
587 } else if (tty->ops->hangup)
588 (tty->ops->hangup)(tty);
590 * We don't want to have driver/ldisc interactions beyond
591 * the ones we did here. The driver layer expects no
592 * calls after ->hangup() from the ldisc side. However we
593 * can't yet guarantee all that.
595 set_bit(TTY_HUPPED, &tty->flags);
596 tty_ldisc_enable(tty);
603 * tty_hangup - trigger a hangup event
604 * @tty: tty to hangup
606 * A carrier loss (virtual or otherwise) has occurred on this like
607 * schedule a hangup sequence to run after this event.
610 void tty_hangup(struct tty_struct *tty)
612 #ifdef TTY_DEBUG_HANGUP
614 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
616 schedule_work(&tty->hangup_work);
619 EXPORT_SYMBOL(tty_hangup);
622 * tty_vhangup - process vhangup
623 * @tty: tty to hangup
625 * The user has asked via system call for the terminal to be hung up.
626 * We do this synchronously so that when the syscall returns the process
627 * is complete. That guarantee is necessary for security reasons.
630 void tty_vhangup(struct tty_struct *tty)
632 #ifdef TTY_DEBUG_HANGUP
635 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
637 do_tty_hangup(&tty->hangup_work);
640 EXPORT_SYMBOL(tty_vhangup);
643 * tty_vhangup_self - process vhangup for own ctty
645 * Perform a vhangup on the current controlling tty
648 void tty_vhangup_self(void)
650 struct tty_struct *tty;
652 tty = get_current_tty();
660 * tty_hung_up_p - was tty hung up
661 * @filp: file pointer of tty
663 * Return true if the tty has been subject to a vhangup or a carrier
667 int tty_hung_up_p(struct file *filp)
669 return (filp->f_op == &hung_up_tty_fops);
672 EXPORT_SYMBOL(tty_hung_up_p);
674 static void session_clear_tty(struct pid *session)
676 struct task_struct *p;
677 do_each_pid_task(session, PIDTYPE_SID, p) {
679 } while_each_pid_task(session, PIDTYPE_SID, p);
683 * disassociate_ctty - disconnect controlling tty
684 * @on_exit: true if exiting so need to "hang up" the session
686 * This function is typically called only by the session leader, when
687 * it wants to disassociate itself from its controlling tty.
689 * It performs the following functions:
690 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
691 * (2) Clears the tty from being controlling the session
692 * (3) Clears the controlling tty for all processes in the
695 * The argument on_exit is set to 1 if called when a process is
696 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
699 * BKL is taken for hysterical raisins
700 * tty_mutex is taken to protect tty
701 * ->siglock is taken to protect ->signal/->sighand
702 * tasklist_lock is taken to walk process list for sessions
703 * ->siglock is taken to protect ->signal/->sighand
706 void disassociate_ctty(int on_exit)
708 struct tty_struct *tty;
709 struct pid *tty_pgrp = NULL;
711 if (!current->signal->leader)
714 tty = get_current_tty();
716 tty_pgrp = get_pid(tty->pgrp);
718 if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY)
722 } else if (on_exit) {
723 struct pid *old_pgrp;
724 spin_lock_irq(¤t->sighand->siglock);
725 old_pgrp = current->signal->tty_old_pgrp;
726 current->signal->tty_old_pgrp = NULL;
727 spin_unlock_irq(¤t->sighand->siglock);
729 kill_pgrp(old_pgrp, SIGHUP, on_exit);
730 kill_pgrp(old_pgrp, SIGCONT, on_exit);
736 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
738 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
742 spin_lock_irq(¤t->sighand->siglock);
743 put_pid(current->signal->tty_old_pgrp);
744 current->signal->tty_old_pgrp = NULL;
745 spin_unlock_irq(¤t->sighand->siglock);
747 tty = get_current_tty();
750 spin_lock_irqsave(&tty->ctrl_lock, flags);
751 put_pid(tty->session);
755 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
758 #ifdef TTY_DEBUG_HANGUP
759 printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
764 /* Now clear signal->tty under the lock */
765 read_lock(&tasklist_lock);
766 session_clear_tty(task_session(current));
767 read_unlock(&tasklist_lock);
772 * no_tty - Ensure the current process does not have a controlling tty
776 struct task_struct *tsk = current;
778 disassociate_ctty(0);
785 * stop_tty - propagate flow control
788 * Perform flow control to the driver. For PTY/TTY pairs we
789 * must also propagate the TIOCKPKT status. May be called
790 * on an already stopped device and will not re-call the driver
793 * This functionality is used by both the line disciplines for
794 * halting incoming flow and by the driver. It may therefore be
795 * called from any context, may be under the tty atomic_write_lock
799 * Uses the tty control lock internally
802 void stop_tty(struct tty_struct *tty)
805 spin_lock_irqsave(&tty->ctrl_lock, flags);
807 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
811 if (tty->link && tty->link->packet) {
812 tty->ctrl_status &= ~TIOCPKT_START;
813 tty->ctrl_status |= TIOCPKT_STOP;
814 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
816 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
818 (tty->ops->stop)(tty);
821 EXPORT_SYMBOL(stop_tty);
824 * start_tty - propagate flow control
827 * Start a tty that has been stopped if at all possible. Perform
828 * any necessary wakeups and propagate the TIOCPKT status. If this
829 * is the tty was previous stopped and is being started then the
830 * driver start method is invoked and the line discipline woken.
836 void start_tty(struct tty_struct *tty)
839 spin_lock_irqsave(&tty->ctrl_lock, flags);
840 if (!tty->stopped || tty->flow_stopped) {
841 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
845 if (tty->link && tty->link->packet) {
846 tty->ctrl_status &= ~TIOCPKT_STOP;
847 tty->ctrl_status |= TIOCPKT_START;
848 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
850 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
852 (tty->ops->start)(tty);
853 /* If we have a running line discipline it may need kicking */
857 EXPORT_SYMBOL(start_tty);
860 * tty_read - read method for tty device files
861 * @file: pointer to tty file
863 * @count: size of user buffer
866 * Perform the read system call function on this terminal device. Checks
867 * for hung up devices before calling the line discipline method.
870 * Locks the line discipline internally while needed. Multiple
871 * read calls may be outstanding in parallel.
874 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
878 struct tty_struct *tty;
880 struct tty_ldisc *ld;
882 tty = (struct tty_struct *)file->private_data;
883 inode = file->f_path.dentry->d_inode;
884 if (tty_paranoia_check(tty, inode, "tty_read"))
886 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
889 /* We want to wait for the line discipline to sort out in this
891 ld = tty_ldisc_ref_wait(tty);
893 i = (ld->ops->read)(tty, file, buf, count);
898 inode->i_atime = current_fs_time(inode->i_sb);
902 void tty_write_unlock(struct tty_struct *tty)
904 mutex_unlock(&tty->atomic_write_lock);
905 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
908 int tty_write_lock(struct tty_struct *tty, int ndelay)
910 if (!mutex_trylock(&tty->atomic_write_lock)) {
913 if (mutex_lock_interruptible(&tty->atomic_write_lock))
920 * Split writes up in sane blocksizes to avoid
921 * denial-of-service type attacks
923 static inline ssize_t do_tty_write(
924 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
925 struct tty_struct *tty,
927 const char __user *buf,
930 ssize_t ret, written = 0;
933 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
938 * We chunk up writes into a temporary buffer. This
939 * simplifies low-level drivers immensely, since they
940 * don't have locking issues and user mode accesses.
942 * But if TTY_NO_WRITE_SPLIT is set, we should use a
945 * The default chunk-size is 2kB, because the NTTY
946 * layer has problems with bigger chunks. It will
947 * claim to be able to handle more characters than
950 * FIXME: This can probably go away now except that 64K chunks
951 * are too likely to fail unless switched to vmalloc...
954 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
959 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
960 if (tty->write_cnt < chunk) {
961 unsigned char *buf_chunk;
966 buf_chunk = kmalloc(chunk, GFP_KERNEL);
971 kfree(tty->write_buf);
972 tty->write_cnt = chunk;
973 tty->write_buf = buf_chunk;
976 /* Do the write .. */
982 if (copy_from_user(tty->write_buf, buf, size))
984 ret = write(tty, file, tty->write_buf, size);
993 if (signal_pending(current))
998 struct inode *inode = file->f_path.dentry->d_inode;
999 inode->i_mtime = current_fs_time(inode->i_sb);
1003 tty_write_unlock(tty);
1008 * tty_write_message - write a message to a certain tty, not just the console.
1009 * @tty: the destination tty_struct
1010 * @msg: the message to write
1012 * This is used for messages that need to be redirected to a specific tty.
1013 * We don't put it into the syslog queue right now maybe in the future if
1016 * We must still hold the BKL and test the CLOSING flag for the moment.
1019 void tty_write_message(struct tty_struct *tty, char *msg)
1022 mutex_lock(&tty->atomic_write_lock);
1024 if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) {
1026 tty->ops->write(tty, msg, strlen(msg));
1029 tty_write_unlock(tty);
1036 * tty_write - write method for tty device file
1037 * @file: tty file pointer
1038 * @buf: user data to write
1039 * @count: bytes to write
1042 * Write data to a tty device via the line discipline.
1045 * Locks the line discipline as required
1046 * Writes to the tty driver are serialized by the atomic_write_lock
1047 * and are then processed in chunks to the device. The line discipline
1048 * write method will not be invoked in parallel for each device.
1051 static ssize_t tty_write(struct file *file, const char __user *buf,
1052 size_t count, loff_t *ppos)
1054 struct tty_struct *tty;
1055 struct inode *inode = file->f_path.dentry->d_inode;
1057 struct tty_ldisc *ld;
1059 tty = (struct tty_struct *)file->private_data;
1060 if (tty_paranoia_check(tty, inode, "tty_write"))
1062 if (!tty || !tty->ops->write ||
1063 (test_bit(TTY_IO_ERROR, &tty->flags)))
1065 /* Short term debug to catch buggy drivers */
1066 if (tty->ops->write_room == NULL)
1067 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1069 ld = tty_ldisc_ref_wait(tty);
1070 if (!ld->ops->write)
1073 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1074 tty_ldisc_deref(ld);
1078 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1079 size_t count, loff_t *ppos)
1081 struct file *p = NULL;
1083 spin_lock(&redirect_lock);
1088 spin_unlock(&redirect_lock);
1092 res = vfs_write(p, buf, count, &p->f_pos);
1096 return tty_write(file, buf, count, ppos);
1099 static char ptychar[] = "pqrstuvwxyzabcde";
1102 * pty_line_name - generate name for a pty
1103 * @driver: the tty driver in use
1104 * @index: the minor number
1105 * @p: output buffer of at least 6 bytes
1107 * Generate a name from a driver reference and write it to the output
1112 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1114 int i = index + driver->name_base;
1115 /* ->name is initialized to "ttyp", but "tty" is expected */
1116 sprintf(p, "%s%c%x",
1117 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1118 ptychar[i >> 4 & 0xf], i & 0xf);
1122 * tty_line_name - generate name for a tty
1123 * @driver: the tty driver in use
1124 * @index: the minor number
1125 * @p: output buffer of at least 7 bytes
1127 * Generate a name from a driver reference and write it to the output
1132 static void tty_line_name(struct tty_driver *driver, int index, char *p)
1134 sprintf(p, "%s%d", driver->name, index + driver->name_base);
1138 * tty_driver_lookup_tty() - find an existing tty, if any
1139 * @driver: the driver for the tty
1140 * @idx: the minor number
1142 * Return the tty, if found or ERR_PTR() otherwise.
1144 * Locking: tty_mutex must be held. If tty is found, the mutex must
1145 * be held until the 'fast-open' is also done. Will change once we
1146 * have refcounting in the driver and per driver locking
1148 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1149 struct inode *inode, int idx)
1151 struct tty_struct *tty;
1153 if (driver->ops->lookup)
1154 return driver->ops->lookup(driver, inode, idx);
1156 tty = driver->ttys[idx];
1161 * tty_init_termios - helper for termios setup
1162 * @tty: the tty to set up
1164 * Initialise the termios structures for this tty. Thus runs under
1165 * the tty_mutex currently so we can be relaxed about ordering.
1168 int tty_init_termios(struct tty_struct *tty)
1170 struct ktermios *tp;
1171 int idx = tty->index;
1173 tp = tty->driver->termios[idx];
1175 tp = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
1178 memcpy(tp, &tty->driver->init_termios,
1179 sizeof(struct ktermios));
1180 tty->driver->termios[idx] = tp;
1183 tty->termios_locked = tp + 1;
1185 /* Compatibility until drivers always set this */
1186 tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
1187 tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
1190 EXPORT_SYMBOL_GPL(tty_init_termios);
1193 * tty_driver_install_tty() - install a tty entry in the driver
1194 * @driver: the driver for the tty
1197 * Install a tty object into the driver tables. The tty->index field
1198 * will be set by the time this is called. This method is responsible
1199 * for ensuring any need additional structures are allocated and
1202 * Locking: tty_mutex for now
1204 static int tty_driver_install_tty(struct tty_driver *driver,
1205 struct tty_struct *tty)
1207 int idx = tty->index;
1210 if (driver->ops->install) {
1212 ret = driver->ops->install(driver, tty);
1217 if (tty_init_termios(tty) == 0) {
1219 tty_driver_kref_get(driver);
1221 driver->ttys[idx] = tty;
1229 * tty_driver_remove_tty() - remove a tty from the driver tables
1230 * @driver: the driver for the tty
1231 * @idx: the minor number
1233 * Remvoe a tty object from the driver tables. The tty->index field
1234 * will be set by the time this is called.
1236 * Locking: tty_mutex for now
1238 static void tty_driver_remove_tty(struct tty_driver *driver,
1239 struct tty_struct *tty)
1241 if (driver->ops->remove)
1242 driver->ops->remove(driver, tty);
1244 driver->ttys[tty->index] = NULL;
1248 * tty_reopen() - fast re-open of an open tty
1249 * @tty - the tty to open
1251 * Return 0 on success, -errno on error.
1253 * Locking: tty_mutex must be held from the time the tty was found
1254 * till this open completes.
1256 static int tty_reopen(struct tty_struct *tty)
1258 struct tty_driver *driver = tty->driver;
1260 if (test_bit(TTY_CLOSING, &tty->flags))
1263 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1264 driver->subtype == PTY_TYPE_MASTER) {
1266 * special case for PTY masters: only one open permitted,
1267 * and the slave side open count is incremented as well.
1275 tty->driver = driver; /* N.B. why do this every time?? */
1277 mutex_lock(&tty->ldisc_mutex);
1278 WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
1279 mutex_unlock(&tty->ldisc_mutex);
1285 * tty_init_dev - initialise a tty device
1286 * @driver: tty driver we are opening a device on
1287 * @idx: device index
1288 * @ret_tty: returned tty structure
1289 * @first_ok: ok to open a new device (used by ptmx)
1291 * Prepare a tty device. This may not be a "new" clean device but
1292 * could also be an active device. The pty drivers require special
1293 * handling because of this.
1296 * The function is called under the tty_mutex, which
1297 * protects us from the tty struct or driver itself going away.
1299 * On exit the tty device has the line discipline attached and
1300 * a reference count of 1. If a pair was created for pty/tty use
1301 * and the other was a pty master then it too has a reference count of 1.
1303 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1304 * failed open. The new code protects the open with a mutex, so it's
1305 * really quite straightforward. The mutex locking can probably be
1306 * relaxed for the (most common) case of reopening a tty.
1309 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx,
1312 struct tty_struct *tty;
1316 /* Check if pty master is being opened multiple times */
1317 if (driver->subtype == PTY_TYPE_MASTER &&
1318 (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok) {
1320 return ERR_PTR(-EIO);
1325 * First time open is complex, especially for PTY devices.
1326 * This code guarantees that either everything succeeds and the
1327 * TTY is ready for operation, or else the table slots are vacated
1328 * and the allocated memory released. (Except that the termios
1329 * and locked termios may be retained.)
1332 if (!try_module_get(driver->owner))
1333 return ERR_PTR(-ENODEV);
1335 tty = alloc_tty_struct();
1338 initialize_tty_struct(tty, driver, idx);
1340 retval = tty_driver_install_tty(driver, tty);
1342 free_tty_struct(tty);
1343 module_put(driver->owner);
1344 return ERR_PTR(retval);
1348 * Structures all installed ... call the ldisc open routines.
1349 * If we fail here just call release_tty to clean up. No need
1350 * to decrement the use counts, as release_tty doesn't care.
1352 retval = tty_ldisc_setup(tty, tty->link);
1354 goto release_mem_out;
1358 module_put(driver->owner);
1359 return ERR_PTR(-ENOMEM);
1361 /* call the tty release_tty routine to clean out this slot */
1363 if (printk_ratelimit())
1364 printk(KERN_INFO "tty_init_dev: ldisc open failed, "
1365 "clearing slot %d\n", idx);
1367 release_tty(tty, idx);
1369 return ERR_PTR(retval);
1372 void tty_free_termios(struct tty_struct *tty)
1374 struct ktermios *tp;
1375 int idx = tty->index;
1376 /* Kill this flag and push into drivers for locking etc */
1377 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
1378 /* FIXME: Locking on ->termios array */
1380 tty->driver->termios[idx] = NULL;
1384 EXPORT_SYMBOL(tty_free_termios);
1386 void tty_shutdown(struct tty_struct *tty)
1388 tty_driver_remove_tty(tty->driver, tty);
1389 tty_free_termios(tty);
1391 EXPORT_SYMBOL(tty_shutdown);
1394 * release_one_tty - release tty structure memory
1395 * @kref: kref of tty we are obliterating
1397 * Releases memory associated with a tty structure, and clears out the
1398 * driver table slots. This function is called when a device is no longer
1399 * in use. It also gets called when setup of a device fails.
1402 * tty_mutex - sometimes only
1403 * takes the file list lock internally when working on the list
1404 * of ttys that the driver keeps.
1406 * This method gets called from a work queue so that the driver private
1407 * cleanup ops can sleep (needed for USB at least)
1409 static void release_one_tty(struct work_struct *work)
1411 struct tty_struct *tty =
1412 container_of(work, struct tty_struct, hangup_work);
1413 struct tty_driver *driver = tty->driver;
1415 if (tty->ops->cleanup)
1416 tty->ops->cleanup(tty);
1419 tty_driver_kref_put(driver);
1420 module_put(driver->owner);
1423 list_del_init(&tty->tty_files);
1427 put_pid(tty->session);
1428 free_tty_struct(tty);
1431 static void queue_release_one_tty(struct kref *kref)
1433 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1435 if (tty->ops->shutdown)
1436 tty->ops->shutdown(tty);
1440 /* The hangup queue is now free so we can reuse it rather than
1441 waste a chunk of memory for each port */
1442 INIT_WORK(&tty->hangup_work, release_one_tty);
1443 schedule_work(&tty->hangup_work);
1447 * tty_kref_put - release a tty kref
1450 * Release a reference to a tty device and if need be let the kref
1451 * layer destruct the object for us
1454 void tty_kref_put(struct tty_struct *tty)
1457 kref_put(&tty->kref, queue_release_one_tty);
1459 EXPORT_SYMBOL(tty_kref_put);
1462 * release_tty - release tty structure memory
1464 * Release both @tty and a possible linked partner (think pty pair),
1465 * and decrement the refcount of the backing module.
1468 * tty_mutex - sometimes only
1469 * takes the file list lock internally when working on the list
1470 * of ttys that the driver keeps.
1471 * FIXME: should we require tty_mutex is held here ??
1474 static void release_tty(struct tty_struct *tty, int idx)
1476 /* This should always be true but check for the moment */
1477 WARN_ON(tty->index != idx);
1480 tty_kref_put(tty->link);
1485 * tty_release - vfs callback for close
1486 * @inode: inode of tty
1487 * @filp: file pointer for handle to tty
1489 * Called the last time each file handle is closed that references
1490 * this tty. There may however be several such references.
1493 * Takes bkl. See tty_release_dev
1495 * Even releasing the tty structures is a tricky business.. We have
1496 * to be very careful that the structures are all released at the
1497 * same time, as interrupts might otherwise get the wrong pointers.
1499 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1500 * lead to double frees or releasing memory still in use.
1503 int tty_release(struct inode *inode, struct file *filp)
1505 struct tty_struct *tty, *o_tty;
1506 int pty_master, tty_closing, o_tty_closing, do_sleep;
1511 tty = (struct tty_struct *)filp->private_data;
1512 if (tty_paranoia_check(tty, inode, "tty_release_dev"))
1516 check_tty_count(tty, "tty_release_dev");
1518 tty_fasync(-1, filp, 0);
1521 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1522 tty->driver->subtype == PTY_TYPE_MASTER);
1523 devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
1526 #ifdef TTY_PARANOIA_CHECK
1527 if (idx < 0 || idx >= tty->driver->num) {
1528 printk(KERN_DEBUG "tty_release_dev: bad idx when trying to "
1529 "free (%s)\n", tty->name);
1534 if (tty != tty->driver->ttys[idx]) {
1536 printk(KERN_DEBUG "tty_release_dev: driver.table[%d] not tty "
1537 "for (%s)\n", idx, tty->name);
1540 if (tty->termios != tty->driver->termios[idx]) {
1542 printk(KERN_DEBUG "tty_release_dev: driver.termios[%d] not termios "
1550 #ifdef TTY_DEBUG_HANGUP
1551 printk(KERN_DEBUG "tty_release_dev of %s (tty count=%d)...",
1552 tty_name(tty, buf), tty->count);
1555 #ifdef TTY_PARANOIA_CHECK
1556 if (tty->driver->other &&
1557 !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
1558 if (o_tty != tty->driver->other->ttys[idx]) {
1560 printk(KERN_DEBUG "tty_release_dev: other->table[%d] "
1561 "not o_tty for (%s)\n",
1565 if (o_tty->termios != tty->driver->other->termios[idx]) {
1567 printk(KERN_DEBUG "tty_release_dev: other->termios[%d] "
1568 "not o_termios for (%s)\n",
1572 if (o_tty->link != tty) {
1574 printk(KERN_DEBUG "tty_release_dev: bad pty pointers\n");
1579 if (tty->ops->close)
1580 tty->ops->close(tty, filp);
1584 * Sanity check: if tty->count is going to zero, there shouldn't be
1585 * any waiters on tty->read_wait or tty->write_wait. We test the
1586 * wait queues and kick everyone out _before_ actually starting to
1587 * close. This ensures that we won't block while releasing the tty
1590 * The test for the o_tty closing is necessary, since the master and
1591 * slave sides may close in any order. If the slave side closes out
1592 * first, its count will be one, since the master side holds an open.
1593 * Thus this test wouldn't be triggered at the time the slave closes,
1596 * Note that it's possible for the tty to be opened again while we're
1597 * flushing out waiters. By recalculating the closing flags before
1598 * each iteration we avoid any problems.
1601 /* Guard against races with tty->count changes elsewhere and
1602 opens on /dev/tty */
1604 mutex_lock(&tty_mutex);
1606 tty_closing = tty->count <= 1;
1607 o_tty_closing = o_tty &&
1608 (o_tty->count <= (pty_master ? 1 : 0));
1612 if (waitqueue_active(&tty->read_wait)) {
1613 wake_up_poll(&tty->read_wait, POLLIN);
1616 if (waitqueue_active(&tty->write_wait)) {
1617 wake_up_poll(&tty->write_wait, POLLOUT);
1621 if (o_tty_closing) {
1622 if (waitqueue_active(&o_tty->read_wait)) {
1623 wake_up_poll(&o_tty->read_wait, POLLIN);
1626 if (waitqueue_active(&o_tty->write_wait)) {
1627 wake_up_poll(&o_tty->write_wait, POLLOUT);
1634 printk(KERN_WARNING "tty_release_dev: %s: read/write wait queue "
1635 "active!\n", tty_name(tty, buf));
1637 mutex_unlock(&tty_mutex);
1642 * The closing flags are now consistent with the open counts on
1643 * both sides, and we've completed the last operation that could
1644 * block, so it's safe to proceed with closing.
1647 if (--o_tty->count < 0) {
1648 printk(KERN_WARNING "tty_release_dev: bad pty slave count "
1650 o_tty->count, tty_name(o_tty, buf));
1654 if (--tty->count < 0) {
1655 printk(KERN_WARNING "tty_release_dev: bad tty->count (%d) for %s\n",
1656 tty->count, tty_name(tty, buf));
1661 * We've decremented tty->count, so we need to remove this file
1662 * descriptor off the tty->tty_files list; this serves two
1664 * - check_tty_count sees the correct number of file descriptors
1665 * associated with this tty.
1666 * - do_tty_hangup no longer sees this file descriptor as
1667 * something that needs to be handled for hangups.
1670 filp->private_data = NULL;
1673 * Perform some housekeeping before deciding whether to return.
1675 * Set the TTY_CLOSING flag if this was the last open. In the
1676 * case of a pty we may have to wait around for the other side
1677 * to close, and TTY_CLOSING makes sure we can't be reopened.
1680 set_bit(TTY_CLOSING, &tty->flags);
1682 set_bit(TTY_CLOSING, &o_tty->flags);
1685 * If _either_ side is closing, make sure there aren't any
1686 * processes that still think tty or o_tty is their controlling
1689 if (tty_closing || o_tty_closing) {
1690 read_lock(&tasklist_lock);
1691 session_clear_tty(tty->session);
1693 session_clear_tty(o_tty->session);
1694 read_unlock(&tasklist_lock);
1697 mutex_unlock(&tty_mutex);
1699 /* check whether both sides are closing ... */
1700 if (!tty_closing || (o_tty && !o_tty_closing)) {
1705 #ifdef TTY_DEBUG_HANGUP
1706 printk(KERN_DEBUG "freeing tty structure...");
1709 * Ask the line discipline code to release its structures
1711 tty_ldisc_release(tty, o_tty);
1713 * The release_tty function takes care of the details of clearing
1714 * the slots and preserving the termios structure.
1716 release_tty(tty, idx);
1718 /* Make this pty number available for reallocation */
1720 devpts_kill_index(inode, idx);
1726 * tty_open - open a tty device
1727 * @inode: inode of device file
1728 * @filp: file pointer to tty
1730 * tty_open and tty_release keep up the tty count that contains the
1731 * number of opens done on a tty. We cannot use the inode-count, as
1732 * different inodes might point to the same tty.
1734 * Open-counting is needed for pty masters, as well as for keeping
1735 * track of serial lines: DTR is dropped when the last close happens.
1736 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1738 * The termios state of a pty is reset on first open so that
1739 * settings don't persist across reuse.
1741 * Locking: tty_mutex protects tty, get_tty_driver and tty_init_dev work.
1742 * tty->count should protect the rest.
1743 * ->siglock protects ->signal/->sighand
1746 static int tty_open(struct inode *inode, struct file *filp)
1748 struct tty_struct *tty = NULL;
1750 struct tty_driver *driver;
1752 dev_t device = inode->i_rdev;
1753 unsigned saved_flags = filp->f_flags;
1755 nonseekable_open(inode, filp);
1758 noctty = filp->f_flags & O_NOCTTY;
1762 mutex_lock(&tty_mutex);
1765 if (device == MKDEV(TTYAUX_MAJOR, 0)) {
1766 tty = get_current_tty();
1769 mutex_unlock(&tty_mutex);
1772 driver = tty_driver_kref_get(tty->driver);
1774 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1776 /* FIXME: Should we take a driver reference ? */
1781 if (device == MKDEV(TTY_MAJOR, 0)) {
1782 extern struct tty_driver *console_driver;
1783 driver = tty_driver_kref_get(console_driver);
1789 if (device == MKDEV(TTYAUX_MAJOR, 1)) {
1790 struct tty_driver *console_driver = console_device(&index);
1791 if (console_driver) {
1792 driver = tty_driver_kref_get(console_driver);
1794 /* Don't let /dev/console block */
1795 filp->f_flags |= O_NONBLOCK;
1801 mutex_unlock(&tty_mutex);
1805 driver = get_tty_driver(device, &index);
1808 mutex_unlock(&tty_mutex);
1813 /* check whether we're reopening an existing tty */
1814 tty = tty_driver_lookup_tty(driver, inode, index);
1818 mutex_unlock(&tty_mutex);
1819 return PTR_ERR(tty);
1824 retval = tty_reopen(tty);
1826 tty = ERR_PTR(retval);
1828 tty = tty_init_dev(driver, index, 0);
1830 mutex_unlock(&tty_mutex);
1831 tty_driver_kref_put(driver);
1834 return PTR_ERR(tty);
1837 filp->private_data = tty;
1838 file_move(filp, &tty->tty_files);
1839 check_tty_count(tty, "tty_open");
1840 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1841 tty->driver->subtype == PTY_TYPE_MASTER)
1843 #ifdef TTY_DEBUG_HANGUP
1844 printk(KERN_DEBUG "opening %s...", tty->name);
1848 retval = tty->ops->open(tty, filp);
1852 filp->f_flags = saved_flags;
1854 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
1855 !capable(CAP_SYS_ADMIN))
1859 #ifdef TTY_DEBUG_HANGUP
1860 printk(KERN_DEBUG "error %d in opening %s...", retval,
1863 tty_release(inode, filp);
1864 if (retval != -ERESTARTSYS) {
1868 if (signal_pending(current)) {
1874 * Need to reset f_op in case a hangup happened.
1876 if (filp->f_op == &hung_up_tty_fops)
1877 filp->f_op = &tty_fops;
1884 mutex_lock(&tty_mutex);
1886 spin_lock_irq(¤t->sighand->siglock);
1888 current->signal->leader &&
1889 !current->signal->tty &&
1890 tty->session == NULL)
1891 __proc_set_tty(current, tty);
1892 spin_unlock_irq(¤t->sighand->siglock);
1894 mutex_unlock(&tty_mutex);
1901 * tty_poll - check tty status
1902 * @filp: file being polled
1903 * @wait: poll wait structures to update
1905 * Call the line discipline polling method to obtain the poll
1906 * status of the device.
1908 * Locking: locks called line discipline but ldisc poll method
1909 * may be re-entered freely by other callers.
1912 static unsigned int tty_poll(struct file *filp, poll_table *wait)
1914 struct tty_struct *tty;
1915 struct tty_ldisc *ld;
1918 tty = (struct tty_struct *)filp->private_data;
1919 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll"))
1922 ld = tty_ldisc_ref_wait(tty);
1924 ret = (ld->ops->poll)(tty, filp, wait);
1925 tty_ldisc_deref(ld);
1929 static int tty_fasync(int fd, struct file *filp, int on)
1931 struct tty_struct *tty;
1932 unsigned long flags;
1936 tty = (struct tty_struct *)filp->private_data;
1937 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
1940 retval = fasync_helper(fd, filp, on, &tty->fasync);
1947 if (!waitqueue_active(&tty->read_wait))
1948 tty->minimum_to_wake = 1;
1949 spin_lock_irqsave(&tty->ctrl_lock, flags);
1952 type = PIDTYPE_PGID;
1954 pid = task_pid(current);
1958 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
1959 retval = __f_setown(filp, pid, type, 0);
1964 if (!tty->fasync && !waitqueue_active(&tty->read_wait))
1965 tty->minimum_to_wake = N_TTY_BUF_SIZE;
1974 * tiocsti - fake input character
1975 * @tty: tty to fake input into
1976 * @p: pointer to character
1978 * Fake input to a tty device. Does the necessary locking and
1981 * FIXME: does not honour flow control ??
1984 * Called functions take tty_ldisc_lock
1985 * current->signal->tty check is safe without locks
1987 * FIXME: may race normal receive processing
1990 static int tiocsti(struct tty_struct *tty, char __user *p)
1993 struct tty_ldisc *ld;
1995 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
1997 if (get_user(ch, p))
1999 tty_audit_tiocsti(tty, ch);
2000 ld = tty_ldisc_ref_wait(tty);
2001 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2002 tty_ldisc_deref(ld);
2007 * tiocgwinsz - implement window query ioctl
2009 * @arg: user buffer for result
2011 * Copies the kernel idea of the window size into the user buffer.
2013 * Locking: tty->termios_mutex is taken to ensure the winsize data
2017 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2021 mutex_lock(&tty->termios_mutex);
2022 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2023 mutex_unlock(&tty->termios_mutex);
2025 return err ? -EFAULT: 0;
2029 * tty_do_resize - resize event
2030 * @tty: tty being resized
2031 * @rows: rows (character)
2032 * @cols: cols (character)
2034 * Update the termios variables and send the necessary signals to
2035 * peform a terminal resize correctly
2038 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2041 unsigned long flags;
2044 mutex_lock(&tty->termios_mutex);
2045 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2047 /* Get the PID values and reference them so we can
2048 avoid holding the tty ctrl lock while sending signals */
2049 spin_lock_irqsave(&tty->ctrl_lock, flags);
2050 pgrp = get_pid(tty->pgrp);
2051 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2054 kill_pgrp(pgrp, SIGWINCH, 1);
2059 mutex_unlock(&tty->termios_mutex);
2064 * tiocswinsz - implement window size set ioctl
2065 * @tty; tty side of tty
2066 * @arg: user buffer for result
2068 * Copies the user idea of the window size to the kernel. Traditionally
2069 * this is just advisory information but for the Linux console it
2070 * actually has driver level meaning and triggers a VC resize.
2073 * Driver dependant. The default do_resize method takes the
2074 * tty termios mutex and ctrl_lock. The console takes its own lock
2075 * then calls into the default method.
2078 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2080 struct winsize tmp_ws;
2081 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2084 if (tty->ops->resize)
2085 return tty->ops->resize(tty, &tmp_ws);
2087 return tty_do_resize(tty, &tmp_ws);
2091 * tioccons - allow admin to move logical console
2092 * @file: the file to become console
2094 * Allow the adminstrator to move the redirected console device
2096 * Locking: uses redirect_lock to guard the redirect information
2099 static int tioccons(struct file *file)
2101 if (!capable(CAP_SYS_ADMIN))
2103 if (file->f_op->write == redirected_tty_write) {
2105 spin_lock(&redirect_lock);
2108 spin_unlock(&redirect_lock);
2113 spin_lock(&redirect_lock);
2115 spin_unlock(&redirect_lock);
2120 spin_unlock(&redirect_lock);
2125 * fionbio - non blocking ioctl
2126 * @file: file to set blocking value
2127 * @p: user parameter
2129 * Historical tty interfaces had a blocking control ioctl before
2130 * the generic functionality existed. This piece of history is preserved
2131 * in the expected tty API of posix OS's.
2133 * Locking: none, the open file handle ensures it won't go away.
2136 static int fionbio(struct file *file, int __user *p)
2140 if (get_user(nonblock, p))
2143 spin_lock(&file->f_lock);
2145 file->f_flags |= O_NONBLOCK;
2147 file->f_flags &= ~O_NONBLOCK;
2148 spin_unlock(&file->f_lock);
2153 * tiocsctty - set controlling tty
2154 * @tty: tty structure
2155 * @arg: user argument
2157 * This ioctl is used to manage job control. It permits a session
2158 * leader to set this tty as the controlling tty for the session.
2161 * Takes tty_mutex() to protect tty instance
2162 * Takes tasklist_lock internally to walk sessions
2163 * Takes ->siglock() when updating signal->tty
2166 static int tiocsctty(struct tty_struct *tty, int arg)
2169 if (current->signal->leader && (task_session(current) == tty->session))
2172 mutex_lock(&tty_mutex);
2174 * The process must be a session leader and
2175 * not have a controlling tty already.
2177 if (!current->signal->leader || current->signal->tty) {
2184 * This tty is already the controlling
2185 * tty for another session group!
2187 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2191 read_lock(&tasklist_lock);
2192 session_clear_tty(tty->session);
2193 read_unlock(&tasklist_lock);
2199 proc_set_tty(current, tty);
2201 mutex_unlock(&tty_mutex);
2206 * tty_get_pgrp - return a ref counted pgrp pid
2209 * Returns a refcounted instance of the pid struct for the process
2210 * group controlling the tty.
2213 struct pid *tty_get_pgrp(struct tty_struct *tty)
2215 unsigned long flags;
2218 spin_lock_irqsave(&tty->ctrl_lock, flags);
2219 pgrp = get_pid(tty->pgrp);
2220 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2224 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2227 * tiocgpgrp - get process group
2228 * @tty: tty passed by user
2229 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2232 * Obtain the process group of the tty. If there is no process group
2235 * Locking: none. Reference to current->signal->tty is safe.
2238 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2243 * (tty == real_tty) is a cheap way of
2244 * testing if the tty is NOT a master pty.
2246 if (tty == real_tty && current->signal->tty != real_tty)
2248 pid = tty_get_pgrp(real_tty);
2249 ret = put_user(pid_vnr(pid), p);
2255 * tiocspgrp - attempt to set process group
2256 * @tty: tty passed by user
2257 * @real_tty: tty side device matching tty passed by user
2260 * Set the process group of the tty to the session passed. Only
2261 * permitted where the tty session is our session.
2263 * Locking: RCU, ctrl lock
2266 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2270 int retval = tty_check_change(real_tty);
2271 unsigned long flags;
2277 if (!current->signal->tty ||
2278 (current->signal->tty != real_tty) ||
2279 (real_tty->session != task_session(current)))
2281 if (get_user(pgrp_nr, p))
2286 pgrp = find_vpid(pgrp_nr);
2291 if (session_of_pgrp(pgrp) != task_session(current))
2294 spin_lock_irqsave(&tty->ctrl_lock, flags);
2295 put_pid(real_tty->pgrp);
2296 real_tty->pgrp = get_pid(pgrp);
2297 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2304 * tiocgsid - get session id
2305 * @tty: tty passed by user
2306 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2307 * @p: pointer to returned session id
2309 * Obtain the session id of the tty. If there is no session
2312 * Locking: none. Reference to current->signal->tty is safe.
2315 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2318 * (tty == real_tty) is a cheap way of
2319 * testing if the tty is NOT a master pty.
2321 if (tty == real_tty && current->signal->tty != real_tty)
2323 if (!real_tty->session)
2325 return put_user(pid_vnr(real_tty->session), p);
2329 * tiocsetd - set line discipline
2331 * @p: pointer to user data
2333 * Set the line discipline according to user request.
2335 * Locking: see tty_set_ldisc, this function is just a helper
2338 static int tiocsetd(struct tty_struct *tty, int __user *p)
2343 if (get_user(ldisc, p))
2346 ret = tty_set_ldisc(tty, ldisc);
2352 * send_break - performed time break
2353 * @tty: device to break on
2354 * @duration: timeout in mS
2356 * Perform a timed break on hardware that lacks its own driver level
2357 * timed break functionality.
2360 * atomic_write_lock serializes
2364 static int send_break(struct tty_struct *tty, unsigned int duration)
2368 if (tty->ops->break_ctl == NULL)
2371 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2372 retval = tty->ops->break_ctl(tty, duration);
2374 /* Do the work ourselves */
2375 if (tty_write_lock(tty, 0) < 0)
2377 retval = tty->ops->break_ctl(tty, -1);
2380 if (!signal_pending(current))
2381 msleep_interruptible(duration);
2382 retval = tty->ops->break_ctl(tty, 0);
2384 tty_write_unlock(tty);
2385 if (signal_pending(current))
2392 * tty_tiocmget - get modem status
2394 * @file: user file pointer
2395 * @p: pointer to result
2397 * Obtain the modem status bits from the tty driver if the feature
2398 * is supported. Return -EINVAL if it is not available.
2400 * Locking: none (up to the driver)
2403 static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p)
2405 int retval = -EINVAL;
2407 if (tty->ops->tiocmget) {
2408 retval = tty->ops->tiocmget(tty, file);
2411 retval = put_user(retval, p);
2417 * tty_tiocmset - set modem status
2419 * @file: user file pointer
2420 * @cmd: command - clear bits, set bits or set all
2421 * @p: pointer to desired bits
2423 * Set the modem status bits from the tty driver if the feature
2424 * is supported. Return -EINVAL if it is not available.
2426 * Locking: none (up to the driver)
2429 static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int cmd,
2433 unsigned int set, clear, val;
2435 if (tty->ops->tiocmset == NULL)
2438 retval = get_user(val, p);
2454 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2455 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2456 return tty->ops->tiocmset(tty, file, set, clear);
2459 struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2461 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2462 tty->driver->subtype == PTY_TYPE_MASTER)
2466 EXPORT_SYMBOL(tty_pair_get_tty);
2468 struct tty_struct *tty_pair_get_pty(struct tty_struct *tty)
2470 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2471 tty->driver->subtype == PTY_TYPE_MASTER)
2475 EXPORT_SYMBOL(tty_pair_get_pty);
2478 * Split this up, as gcc can choke on it otherwise..
2480 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2482 struct tty_struct *tty, *real_tty;
2483 void __user *p = (void __user *)arg;
2485 struct tty_ldisc *ld;
2486 struct inode *inode = file->f_dentry->d_inode;
2488 tty = (struct tty_struct *)file->private_data;
2489 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2492 real_tty = tty_pair_get_tty(tty);
2495 * Factor out some common prep work
2503 retval = tty_check_change(tty);
2506 if (cmd != TIOCCBRK) {
2507 tty_wait_until_sent(tty, 0);
2508 if (signal_pending(current))
2519 return tiocsti(tty, p);
2521 return tiocgwinsz(real_tty, p);
2523 return tiocswinsz(real_tty, p);
2525 return real_tty != tty ? -EINVAL : tioccons(file);
2527 return fionbio(file, p);
2529 set_bit(TTY_EXCLUSIVE, &tty->flags);
2532 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2535 if (current->signal->tty != tty)
2540 return tiocsctty(tty, arg);
2542 return tiocgpgrp(tty, real_tty, p);
2544 return tiocspgrp(tty, real_tty, p);
2546 return tiocgsid(tty, real_tty, p);
2548 return put_user(tty->ldisc->ops->num, (int __user *)p);
2550 return tiocsetd(tty, p);
2554 case TIOCSBRK: /* Turn break on, unconditionally */
2555 if (tty->ops->break_ctl)
2556 return tty->ops->break_ctl(tty, -1);
2558 case TIOCCBRK: /* Turn break off, unconditionally */
2559 if (tty->ops->break_ctl)
2560 return tty->ops->break_ctl(tty, 0);
2562 case TCSBRK: /* SVID version: non-zero arg --> no break */
2563 /* non-zero arg means wait for all output data
2564 * to be sent (performed above) but don't send break.
2565 * This is used by the tcdrain() termios function.
2568 return send_break(tty, 250);
2570 case TCSBRKP: /* support for POSIX tcsendbreak() */
2571 return send_break(tty, arg ? arg*100 : 250);
2574 return tty_tiocmget(tty, file, p);
2578 return tty_tiocmset(tty, file, cmd, p);
2583 /* flush tty buffer and allow ldisc to process ioctl */
2584 tty_buffer_flush(tty);
2589 if (tty->ops->ioctl) {
2590 retval = (tty->ops->ioctl)(tty, file, cmd, arg);
2591 if (retval != -ENOIOCTLCMD)
2594 ld = tty_ldisc_ref_wait(tty);
2596 if (ld->ops->ioctl) {
2597 retval = ld->ops->ioctl(tty, file, cmd, arg);
2598 if (retval == -ENOIOCTLCMD)
2601 tty_ldisc_deref(ld);
2605 #ifdef CONFIG_COMPAT
2606 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2609 struct inode *inode = file->f_dentry->d_inode;
2610 struct tty_struct *tty = file->private_data;
2611 struct tty_ldisc *ld;
2612 int retval = -ENOIOCTLCMD;
2614 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2617 if (tty->ops->compat_ioctl) {
2618 retval = (tty->ops->compat_ioctl)(tty, file, cmd, arg);
2619 if (retval != -ENOIOCTLCMD)
2623 ld = tty_ldisc_ref_wait(tty);
2624 if (ld->ops->compat_ioctl)
2625 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2626 tty_ldisc_deref(ld);
2633 * This implements the "Secure Attention Key" --- the idea is to
2634 * prevent trojan horses by killing all processes associated with this
2635 * tty when the user hits the "Secure Attention Key". Required for
2636 * super-paranoid applications --- see the Orange Book for more details.
2638 * This code could be nicer; ideally it should send a HUP, wait a few
2639 * seconds, then send a INT, and then a KILL signal. But you then
2640 * have to coordinate with the init process, since all processes associated
2641 * with the current tty must be dead before the new getty is allowed
2644 * Now, if it would be correct ;-/ The current code has a nasty hole -
2645 * it doesn't catch files in flight. We may send the descriptor to ourselves
2646 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2648 * Nasty bug: do_SAK is being called in interrupt context. This can
2649 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2651 void __do_SAK(struct tty_struct *tty)
2656 struct task_struct *g, *p;
2657 struct pid *session;
2660 struct fdtable *fdt;
2664 session = tty->session;
2666 tty_ldisc_flush(tty);
2668 tty_driver_flush_buffer(tty);
2670 read_lock(&tasklist_lock);
2671 /* Kill the entire session */
2672 do_each_pid_task(session, PIDTYPE_SID, p) {
2673 printk(KERN_NOTICE "SAK: killed process %d"
2674 " (%s): task_session(p)==tty->session\n",
2675 task_pid_nr(p), p->comm);
2676 send_sig(SIGKILL, p, 1);
2677 } while_each_pid_task(session, PIDTYPE_SID, p);
2678 /* Now kill any processes that happen to have the
2681 do_each_thread(g, p) {
2682 if (p->signal->tty == tty) {
2683 printk(KERN_NOTICE "SAK: killed process %d"
2684 " (%s): task_session(p)==tty->session\n",
2685 task_pid_nr(p), p->comm);
2686 send_sig(SIGKILL, p, 1);
2692 * We don't take a ref to the file, so we must
2693 * hold ->file_lock instead.
2695 spin_lock(&p->files->file_lock);
2696 fdt = files_fdtable(p->files);
2697 for (i = 0; i < fdt->max_fds; i++) {
2698 filp = fcheck_files(p->files, i);
2701 if (filp->f_op->read == tty_read &&
2702 filp->private_data == tty) {
2703 printk(KERN_NOTICE "SAK: killed process %d"
2704 " (%s): fd#%d opened to the tty\n",
2705 task_pid_nr(p), p->comm, i);
2706 force_sig(SIGKILL, p);
2710 spin_unlock(&p->files->file_lock);
2713 } while_each_thread(g, p);
2714 read_unlock(&tasklist_lock);
2718 static void do_SAK_work(struct work_struct *work)
2720 struct tty_struct *tty =
2721 container_of(work, struct tty_struct, SAK_work);
2726 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2727 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2728 * the values which we write to it will be identical to the values which it
2729 * already has. --akpm
2731 void do_SAK(struct tty_struct *tty)
2735 schedule_work(&tty->SAK_work);
2738 EXPORT_SYMBOL(do_SAK);
2741 * initialize_tty_struct
2742 * @tty: tty to initialize
2744 * This subroutine initializes a tty structure that has been newly
2747 * Locking: none - tty in question must not be exposed at this point
2750 void initialize_tty_struct(struct tty_struct *tty,
2751 struct tty_driver *driver, int idx)
2753 memset(tty, 0, sizeof(struct tty_struct));
2754 kref_init(&tty->kref);
2755 tty->magic = TTY_MAGIC;
2756 tty_ldisc_init(tty);
2757 tty->session = NULL;
2759 tty->overrun_time = jiffies;
2760 tty->buf.head = tty->buf.tail = NULL;
2761 tty_buffer_init(tty);
2762 mutex_init(&tty->termios_mutex);
2763 mutex_init(&tty->ldisc_mutex);
2764 init_waitqueue_head(&tty->write_wait);
2765 init_waitqueue_head(&tty->read_wait);
2766 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2767 mutex_init(&tty->atomic_read_lock);
2768 mutex_init(&tty->atomic_write_lock);
2769 mutex_init(&tty->output_lock);
2770 mutex_init(&tty->echo_lock);
2771 spin_lock_init(&tty->read_lock);
2772 spin_lock_init(&tty->ctrl_lock);
2773 INIT_LIST_HEAD(&tty->tty_files);
2774 INIT_WORK(&tty->SAK_work, do_SAK_work);
2776 tty->driver = driver;
2777 tty->ops = driver->ops;
2779 tty_line_name(driver, idx, tty->name);
2783 * tty_put_char - write one character to a tty
2787 * Write one byte to the tty using the provided put_char method
2788 * if present. Returns the number of characters successfully output.
2790 * Note: the specific put_char operation in the driver layer may go
2791 * away soon. Don't call it directly, use this method
2794 int tty_put_char(struct tty_struct *tty, unsigned char ch)
2796 if (tty->ops->put_char)
2797 return tty->ops->put_char(tty, ch);
2798 return tty->ops->write(tty, &ch, 1);
2800 EXPORT_SYMBOL_GPL(tty_put_char);
2802 struct class *tty_class;
2805 * tty_register_device - register a tty device
2806 * @driver: the tty driver that describes the tty device
2807 * @index: the index in the tty driver for this tty device
2808 * @device: a struct device that is associated with this tty device.
2809 * This field is optional, if there is no known struct device
2810 * for this tty device it can be set to NULL safely.
2812 * Returns a pointer to the struct device for this tty device
2813 * (or ERR_PTR(-EFOO) on error).
2815 * This call is required to be made to register an individual tty device
2816 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2817 * that bit is not set, this function should not be called by a tty
2823 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
2824 struct device *device)
2827 dev_t dev = MKDEV(driver->major, driver->minor_start) + index;
2829 if (index >= driver->num) {
2830 printk(KERN_ERR "Attempt to register invalid tty line number "
2832 return ERR_PTR(-EINVAL);
2835 if (driver->type == TTY_DRIVER_TYPE_PTY)
2836 pty_line_name(driver, index, name);
2838 tty_line_name(driver, index, name);
2840 return device_create(tty_class, device, dev, NULL, name);
2842 EXPORT_SYMBOL(tty_register_device);
2845 * tty_unregister_device - unregister a tty device
2846 * @driver: the tty driver that describes the tty device
2847 * @index: the index in the tty driver for this tty device
2849 * If a tty device is registered with a call to tty_register_device() then
2850 * this function must be called when the tty device is gone.
2855 void tty_unregister_device(struct tty_driver *driver, unsigned index)
2857 device_destroy(tty_class,
2858 MKDEV(driver->major, driver->minor_start) + index);
2860 EXPORT_SYMBOL(tty_unregister_device);
2862 struct tty_driver *alloc_tty_driver(int lines)
2864 struct tty_driver *driver;
2866 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
2868 kref_init(&driver->kref);
2869 driver->magic = TTY_DRIVER_MAGIC;
2870 driver->num = lines;
2871 /* later we'll move allocation of tables here */
2875 EXPORT_SYMBOL(alloc_tty_driver);
2877 static void destruct_tty_driver(struct kref *kref)
2879 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
2881 struct ktermios *tp;
2884 if (driver->flags & TTY_DRIVER_INSTALLED) {
2886 * Free the termios and termios_locked structures because
2887 * we don't want to get memory leaks when modular tty
2888 * drivers are removed from the kernel.
2890 for (i = 0; i < driver->num; i++) {
2891 tp = driver->termios[i];
2893 driver->termios[i] = NULL;
2896 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
2897 tty_unregister_device(driver, i);
2900 proc_tty_unregister_driver(driver);
2901 driver->ttys = NULL;
2902 driver->termios = NULL;
2904 cdev_del(&driver->cdev);
2909 void tty_driver_kref_put(struct tty_driver *driver)
2911 kref_put(&driver->kref, destruct_tty_driver);
2913 EXPORT_SYMBOL(tty_driver_kref_put);
2915 void tty_set_operations(struct tty_driver *driver,
2916 const struct tty_operations *op)
2920 EXPORT_SYMBOL(tty_set_operations);
2922 void put_tty_driver(struct tty_driver *d)
2924 tty_driver_kref_put(d);
2926 EXPORT_SYMBOL(put_tty_driver);
2929 * Called by a tty driver to register itself.
2931 int tty_register_driver(struct tty_driver *driver)
2938 if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) {
2939 p = kzalloc(driver->num * 2 * sizeof(void *), GFP_KERNEL);
2944 if (!driver->major) {
2945 error = alloc_chrdev_region(&dev, driver->minor_start,
2946 driver->num, driver->name);
2948 driver->major = MAJOR(dev);
2949 driver->minor_start = MINOR(dev);
2952 dev = MKDEV(driver->major, driver->minor_start);
2953 error = register_chrdev_region(dev, driver->num, driver->name);
2961 driver->ttys = (struct tty_struct **)p;
2962 driver->termios = (struct ktermios **)(p + driver->num);
2964 driver->ttys = NULL;
2965 driver->termios = NULL;
2968 cdev_init(&driver->cdev, &tty_fops);
2969 driver->cdev.owner = driver->owner;
2970 error = cdev_add(&driver->cdev, dev, driver->num);
2972 unregister_chrdev_region(dev, driver->num);
2973 driver->ttys = NULL;
2974 driver->termios = NULL;
2979 mutex_lock(&tty_mutex);
2980 list_add(&driver->tty_drivers, &tty_drivers);
2981 mutex_unlock(&tty_mutex);
2983 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
2984 for (i = 0; i < driver->num; i++)
2985 tty_register_device(driver, i, NULL);
2987 proc_tty_register_driver(driver);
2988 driver->flags |= TTY_DRIVER_INSTALLED;
2992 EXPORT_SYMBOL(tty_register_driver);
2995 * Called by a tty driver to unregister itself.
2997 int tty_unregister_driver(struct tty_driver *driver)
3001 if (driver->refcount)
3004 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3006 mutex_lock(&tty_mutex);
3007 list_del(&driver->tty_drivers);
3008 mutex_unlock(&tty_mutex);
3012 EXPORT_SYMBOL(tty_unregister_driver);
3014 dev_t tty_devnum(struct tty_struct *tty)
3016 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3018 EXPORT_SYMBOL(tty_devnum);
3020 void proc_clear_tty(struct task_struct *p)
3022 unsigned long flags;
3023 struct tty_struct *tty;
3024 spin_lock_irqsave(&p->sighand->siglock, flags);
3025 tty = p->signal->tty;
3026 p->signal->tty = NULL;
3027 spin_unlock_irqrestore(&p->sighand->siglock, flags);
3031 /* Called under the sighand lock */
3033 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3036 unsigned long flags;
3037 /* We should not have a session or pgrp to put here but.... */
3038 spin_lock_irqsave(&tty->ctrl_lock, flags);
3039 put_pid(tty->session);
3041 tty->pgrp = get_pid(task_pgrp(tsk));
3042 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3043 tty->session = get_pid(task_session(tsk));
3044 if (tsk->signal->tty) {
3045 printk(KERN_DEBUG "tty not NULL!!\n");
3046 tty_kref_put(tsk->signal->tty);
3049 put_pid(tsk->signal->tty_old_pgrp);
3050 tsk->signal->tty = tty_kref_get(tty);
3051 tsk->signal->tty_old_pgrp = NULL;
3054 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3056 spin_lock_irq(&tsk->sighand->siglock);
3057 __proc_set_tty(tsk, tty);
3058 spin_unlock_irq(&tsk->sighand->siglock);
3061 struct tty_struct *get_current_tty(void)
3063 struct tty_struct *tty;
3064 unsigned long flags;
3066 spin_lock_irqsave(¤t->sighand->siglock, flags);
3067 tty = tty_kref_get(current->signal->tty);
3068 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
3071 EXPORT_SYMBOL_GPL(get_current_tty);
3073 void tty_default_fops(struct file_operations *fops)
3079 * Initialize the console device. This is called *early*, so
3080 * we can't necessarily depend on lots of kernel help here.
3081 * Just do some early initializations, and do the complex setup
3084 void __init console_init(void)
3088 /* Setup the default TTY line discipline. */
3092 * set up the console device so that later boot sequences can
3093 * inform about problems etc..
3095 call = __con_initcall_start;
3096 while (call < __con_initcall_end) {
3102 static char *tty_devnode(struct device *dev, mode_t *mode)
3106 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3107 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3112 static int __init tty_class_init(void)
3114 tty_class = class_create(THIS_MODULE, "tty");
3115 if (IS_ERR(tty_class))
3116 return PTR_ERR(tty_class);
3117 tty_class->devnode = tty_devnode;
3121 postcore_initcall(tty_class_init);
3123 /* 3/2004 jmc: why do these devices exist? */
3125 static struct cdev tty_cdev, console_cdev;
3128 * Ok, now we can initialize the rest of the tty devices and can count
3129 * on memory allocations, interrupts etc..
3131 static int __init tty_init(void)
3133 cdev_init(&tty_cdev, &tty_fops);
3134 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3135 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3136 panic("Couldn't register /dev/tty driver\n");
3137 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL,
3140 cdev_init(&console_cdev, &console_fops);
3141 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3142 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3143 panic("Couldn't register /dev/console driver\n");
3144 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3148 vty_init(&console_fops);
3152 module_init(tty_init);