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 /* Spinlock to protect the tty->tty_files list */
140 DEFINE_SPINLOCK(tty_files_lock);
142 static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
143 static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
144 ssize_t redirected_tty_write(struct file *, const char __user *,
146 static unsigned int tty_poll(struct file *, poll_table *);
147 static int tty_open(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 int tty_fasync(int fd, struct file *filp, int on);
157 static void release_tty(struct tty_struct *tty, int idx);
158 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
159 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
162 * alloc_tty_struct - allocate a tty object
164 * Return a new empty tty structure. The data fields have not
165 * been initialized in any way but has been zeroed
170 struct tty_struct *alloc_tty_struct(void)
172 return kzalloc(sizeof(struct tty_struct), GFP_KERNEL);
176 * free_tty_struct - free a disused tty
177 * @tty: tty struct to free
179 * Free the write buffers, tty queue and tty memory itself.
181 * Locking: none. Must be called after tty is definitely unused
184 void free_tty_struct(struct tty_struct *tty)
187 put_device(tty->dev);
188 kfree(tty->write_buf);
189 tty_buffer_free_all(tty);
193 static inline struct tty_struct *file_tty(struct file *file)
195 return ((struct tty_file_private *)file->private_data)->tty;
198 /* Associate a new file with the tty structure */
199 int tty_add_file(struct tty_struct *tty, struct file *file)
201 struct tty_file_private *priv;
203 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
209 file->private_data = priv;
211 spin_lock(&tty_files_lock);
212 list_add(&priv->list, &tty->tty_files);
213 spin_unlock(&tty_files_lock);
218 /* Delete file from its tty */
219 void tty_del_file(struct file *file)
221 struct tty_file_private *priv = file->private_data;
223 spin_lock(&tty_files_lock);
224 list_del(&priv->list);
225 spin_unlock(&tty_files_lock);
226 file->private_data = NULL;
231 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
234 * tty_name - return tty naming
235 * @tty: tty structure
236 * @buf: buffer for output
238 * Convert a tty structure into a name. The name reflects the kernel
239 * naming policy and if udev is in use may not reflect user space
244 char *tty_name(struct tty_struct *tty, char *buf)
246 if (!tty) /* Hmm. NULL pointer. That's fun. */
247 strcpy(buf, "NULL tty");
249 strcpy(buf, tty->name);
253 EXPORT_SYMBOL(tty_name);
255 int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
258 #ifdef TTY_PARANOIA_CHECK
261 "null TTY for (%d:%d) in %s\n",
262 imajor(inode), iminor(inode), routine);
265 if (tty->magic != TTY_MAGIC) {
267 "bad magic number for tty struct (%d:%d) in %s\n",
268 imajor(inode), iminor(inode), routine);
275 static int check_tty_count(struct tty_struct *tty, const char *routine)
277 #ifdef CHECK_TTY_COUNT
281 spin_lock(&tty_files_lock);
282 list_for_each(p, &tty->tty_files) {
285 spin_unlock(&tty_files_lock);
286 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
287 tty->driver->subtype == PTY_TYPE_SLAVE &&
288 tty->link && tty->link->count)
290 if (tty->count != count) {
291 printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) "
292 "!= #fd's(%d) in %s\n",
293 tty->name, tty->count, count, routine);
301 * get_tty_driver - find device of a tty
302 * @dev_t: device identifier
303 * @index: returns the index of the tty
305 * This routine returns a tty driver structure, given a device number
306 * and also passes back the index number.
308 * Locking: caller must hold tty_mutex
311 static struct tty_driver *get_tty_driver(dev_t device, int *index)
313 struct tty_driver *p;
315 list_for_each_entry(p, &tty_drivers, tty_drivers) {
316 dev_t base = MKDEV(p->major, p->minor_start);
317 if (device < base || device >= base + p->num)
319 *index = device - base;
320 return tty_driver_kref_get(p);
325 #ifdef CONFIG_CONSOLE_POLL
328 * tty_find_polling_driver - find device of a polled tty
329 * @name: name string to match
330 * @line: pointer to resulting tty line nr
332 * This routine returns a tty driver structure, given a name
333 * and the condition that the tty driver is capable of polled
336 struct tty_driver *tty_find_polling_driver(char *name, int *line)
338 struct tty_driver *p, *res = NULL;
343 for (str = name; *str; str++)
344 if ((*str >= '0' && *str <= '9') || *str == ',')
350 tty_line = simple_strtoul(str, &str, 10);
352 mutex_lock(&tty_mutex);
353 /* Search through the tty devices to look for a match */
354 list_for_each_entry(p, &tty_drivers, tty_drivers) {
355 if (strncmp(name, p->name, len) != 0)
363 if (tty_line >= 0 && tty_line < p->num && p->ops &&
364 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
365 res = tty_driver_kref_get(p);
370 mutex_unlock(&tty_mutex);
374 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
378 * tty_check_change - check for POSIX terminal changes
381 * If we try to write to, or set the state of, a terminal and we're
382 * not in the foreground, send a SIGTTOU. If the signal is blocked or
383 * ignored, go ahead and perform the operation. (POSIX 7.2)
388 int tty_check_change(struct tty_struct *tty)
393 if (current->signal->tty != tty)
396 spin_lock_irqsave(&tty->ctrl_lock, flags);
399 printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
402 if (task_pgrp(current) == tty->pgrp)
404 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
405 if (is_ignored(SIGTTOU))
407 if (is_current_pgrp_orphaned()) {
411 kill_pgrp(task_pgrp(current), SIGTTOU, 1);
412 set_thread_flag(TIF_SIGPENDING);
417 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
421 EXPORT_SYMBOL(tty_check_change);
423 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
424 size_t count, loff_t *ppos)
429 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
430 size_t count, loff_t *ppos)
435 /* No kernel lock held - none needed ;) */
436 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
438 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
441 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
444 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
447 static long hung_up_tty_compat_ioctl(struct file *file,
448 unsigned int cmd, unsigned long arg)
450 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
453 static const struct file_operations tty_fops = {
458 .unlocked_ioctl = tty_ioctl,
459 .compat_ioctl = tty_compat_ioctl,
461 .release = tty_release,
462 .fasync = tty_fasync,
465 static const struct file_operations console_fops = {
468 .write = redirected_tty_write,
470 .unlocked_ioctl = tty_ioctl,
471 .compat_ioctl = tty_compat_ioctl,
473 .release = tty_release,
474 .fasync = tty_fasync,
477 static const struct file_operations hung_up_tty_fops = {
479 .read = hung_up_tty_read,
480 .write = hung_up_tty_write,
481 .poll = hung_up_tty_poll,
482 .unlocked_ioctl = hung_up_tty_ioctl,
483 .compat_ioctl = hung_up_tty_compat_ioctl,
484 .release = tty_release,
487 static DEFINE_SPINLOCK(redirect_lock);
488 static struct file *redirect;
491 * tty_wakeup - request more data
494 * Internal and external helper for wakeups of tty. This function
495 * informs the line discipline if present that the driver is ready
496 * to receive more output data.
499 void tty_wakeup(struct tty_struct *tty)
501 struct tty_ldisc *ld;
503 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
504 ld = tty_ldisc_ref(tty);
506 if (ld->ops->write_wakeup)
507 ld->ops->write_wakeup(tty);
511 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
514 EXPORT_SYMBOL_GPL(tty_wakeup);
517 * __tty_hangup - actual handler for hangup events
520 * This can be called by the "eventd" kernel thread. That is process
521 * synchronous but doesn't hold any locks, so we need to make sure we
522 * have the appropriate locks for what we're doing.
524 * The hangup event clears any pending redirections onto the hung up
525 * device. It ensures future writes will error and it does the needed
526 * line discipline hangup and signal delivery. The tty object itself
531 * redirect lock for undoing redirection
532 * file list lock for manipulating list of ttys
533 * tty_ldisc_lock from called functions
534 * termios_mutex resetting termios data
535 * tasklist_lock to walk task list for hangup event
536 * ->siglock to protect ->signal/->sighand
538 void __tty_hangup(struct tty_struct *tty)
540 struct file *cons_filp = NULL;
541 struct file *filp, *f = NULL;
542 struct task_struct *p;
543 struct tty_file_private *priv;
544 int closecount = 0, n;
552 spin_lock(&redirect_lock);
553 if (redirect && file_tty(redirect) == tty) {
557 spin_unlock(&redirect_lock);
561 /* inuse_filps is protected by the single tty lock,
562 this really needs to change if we want to flush the
563 workqueue with the lock held */
564 check_tty_count(tty, "tty_hangup");
566 spin_lock(&tty_files_lock);
567 /* This breaks for file handles being sent over AF_UNIX sockets ? */
568 list_for_each_entry(priv, &tty->tty_files, list) {
570 if (filp->f_op->write == redirected_tty_write)
572 if (filp->f_op->write != tty_write)
575 __tty_fasync(-1, filp, 0); /* can't block */
576 filp->f_op = &hung_up_tty_fops;
578 spin_unlock(&tty_files_lock);
580 tty_ldisc_hangup(tty);
582 read_lock(&tasklist_lock);
584 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
585 spin_lock_irq(&p->sighand->siglock);
586 if (p->signal->tty == tty) {
587 p->signal->tty = NULL;
588 /* We defer the dereferences outside fo
592 if (!p->signal->leader) {
593 spin_unlock_irq(&p->sighand->siglock);
596 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
597 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
598 put_pid(p->signal->tty_old_pgrp); /* A noop */
599 spin_lock_irqsave(&tty->ctrl_lock, flags);
601 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
602 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
603 spin_unlock_irq(&p->sighand->siglock);
604 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
606 read_unlock(&tasklist_lock);
608 spin_lock_irqsave(&tty->ctrl_lock, flags);
609 clear_bit(TTY_THROTTLED, &tty->flags);
610 clear_bit(TTY_PUSH, &tty->flags);
611 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
612 put_pid(tty->session);
616 tty->ctrl_status = 0;
617 set_bit(TTY_HUPPED, &tty->flags);
618 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
620 /* Account for the p->signal references we killed */
625 * If one of the devices matches a console pointer, we
626 * cannot just call hangup() because that will cause
627 * tty->count and state->count to go out of sync.
628 * So we just call close() the right number of times.
632 for (n = 0; n < closecount; n++)
633 tty->ops->close(tty, cons_filp);
634 } else if (tty->ops->hangup)
635 (tty->ops->hangup)(tty);
637 * We don't want to have driver/ldisc interactions beyond
638 * the ones we did here. The driver layer expects no
639 * calls after ->hangup() from the ldisc side. However we
640 * can't yet guarantee all that.
642 set_bit(TTY_HUPPED, &tty->flags);
643 tty_ldisc_enable(tty);
651 static void do_tty_hangup(struct work_struct *work)
653 struct tty_struct *tty =
654 container_of(work, struct tty_struct, hangup_work);
660 * tty_hangup - trigger a hangup event
661 * @tty: tty to hangup
663 * A carrier loss (virtual or otherwise) has occurred on this like
664 * schedule a hangup sequence to run after this event.
667 void tty_hangup(struct tty_struct *tty)
669 #ifdef TTY_DEBUG_HANGUP
671 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
673 schedule_work(&tty->hangup_work);
676 EXPORT_SYMBOL(tty_hangup);
679 * tty_vhangup - process vhangup
680 * @tty: tty to hangup
682 * The user has asked via system call for the terminal to be hung up.
683 * We do this synchronously so that when the syscall returns the process
684 * is complete. That guarantee is necessary for security reasons.
687 void tty_vhangup(struct tty_struct *tty)
689 #ifdef TTY_DEBUG_HANGUP
692 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
697 EXPORT_SYMBOL(tty_vhangup);
701 * tty_vhangup_self - process vhangup for own ctty
703 * Perform a vhangup on the current controlling tty
706 void tty_vhangup_self(void)
708 struct tty_struct *tty;
710 tty = get_current_tty();
718 * tty_hung_up_p - was tty hung up
719 * @filp: file pointer of tty
721 * Return true if the tty has been subject to a vhangup or a carrier
725 int tty_hung_up_p(struct file *filp)
727 return (filp->f_op == &hung_up_tty_fops);
730 EXPORT_SYMBOL(tty_hung_up_p);
732 static void session_clear_tty(struct pid *session)
734 struct task_struct *p;
735 do_each_pid_task(session, PIDTYPE_SID, p) {
737 } while_each_pid_task(session, PIDTYPE_SID, p);
741 * disassociate_ctty - disconnect controlling tty
742 * @on_exit: true if exiting so need to "hang up" the session
744 * This function is typically called only by the session leader, when
745 * it wants to disassociate itself from its controlling tty.
747 * It performs the following functions:
748 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
749 * (2) Clears the tty from being controlling the session
750 * (3) Clears the controlling tty for all processes in the
753 * The argument on_exit is set to 1 if called when a process is
754 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
757 * BTM is taken for hysterical raisins, and held when
758 * called from no_tty().
759 * tty_mutex is taken to protect tty
760 * ->siglock is taken to protect ->signal/->sighand
761 * tasklist_lock is taken to walk process list for sessions
762 * ->siglock is taken to protect ->signal/->sighand
765 void disassociate_ctty(int on_exit)
767 struct tty_struct *tty;
768 struct pid *tty_pgrp = NULL;
770 if (!current->signal->leader)
773 tty = get_current_tty();
775 tty_pgrp = get_pid(tty->pgrp);
777 if (tty->driver->type != TTY_DRIVER_TYPE_PTY)
781 } else if (on_exit) {
782 struct pid *old_pgrp;
783 spin_lock_irq(¤t->sighand->siglock);
784 old_pgrp = current->signal->tty_old_pgrp;
785 current->signal->tty_old_pgrp = NULL;
786 spin_unlock_irq(¤t->sighand->siglock);
788 kill_pgrp(old_pgrp, SIGHUP, on_exit);
789 kill_pgrp(old_pgrp, SIGCONT, on_exit);
795 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
797 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
801 spin_lock_irq(¤t->sighand->siglock);
802 put_pid(current->signal->tty_old_pgrp);
803 current->signal->tty_old_pgrp = NULL;
804 spin_unlock_irq(¤t->sighand->siglock);
806 tty = get_current_tty();
809 spin_lock_irqsave(&tty->ctrl_lock, flags);
810 put_pid(tty->session);
814 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
817 #ifdef TTY_DEBUG_HANGUP
818 printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
823 /* Now clear signal->tty under the lock */
824 read_lock(&tasklist_lock);
825 session_clear_tty(task_session(current));
826 read_unlock(&tasklist_lock);
831 * no_tty - Ensure the current process does not have a controlling tty
835 struct task_struct *tsk = current;
837 disassociate_ctty(0);
844 * stop_tty - propagate flow control
847 * Perform flow control to the driver. For PTY/TTY pairs we
848 * must also propagate the TIOCKPKT status. May be called
849 * on an already stopped device and will not re-call the driver
852 * This functionality is used by both the line disciplines for
853 * halting incoming flow and by the driver. It may therefore be
854 * called from any context, may be under the tty atomic_write_lock
858 * Uses the tty control lock internally
861 void stop_tty(struct tty_struct *tty)
864 spin_lock_irqsave(&tty->ctrl_lock, flags);
866 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
870 if (tty->link && tty->link->packet) {
871 tty->ctrl_status &= ~TIOCPKT_START;
872 tty->ctrl_status |= TIOCPKT_STOP;
873 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
875 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
877 (tty->ops->stop)(tty);
880 EXPORT_SYMBOL(stop_tty);
883 * start_tty - propagate flow control
886 * Start a tty that has been stopped if at all possible. Perform
887 * any necessary wakeups and propagate the TIOCPKT status. If this
888 * is the tty was previous stopped and is being started then the
889 * driver start method is invoked and the line discipline woken.
895 void start_tty(struct tty_struct *tty)
898 spin_lock_irqsave(&tty->ctrl_lock, flags);
899 if (!tty->stopped || tty->flow_stopped) {
900 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
904 if (tty->link && tty->link->packet) {
905 tty->ctrl_status &= ~TIOCPKT_STOP;
906 tty->ctrl_status |= TIOCPKT_START;
907 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
909 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
911 (tty->ops->start)(tty);
912 /* If we have a running line discipline it may need kicking */
916 EXPORT_SYMBOL(start_tty);
919 * tty_read - read method for tty device files
920 * @file: pointer to tty file
922 * @count: size of user buffer
925 * Perform the read system call function on this terminal device. Checks
926 * for hung up devices before calling the line discipline method.
929 * Locks the line discipline internally while needed. Multiple
930 * read calls may be outstanding in parallel.
933 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
937 struct inode *inode = file->f_path.dentry->d_inode;
938 struct tty_struct *tty = file_tty(file);
939 struct tty_ldisc *ld;
941 if (tty_paranoia_check(tty, inode, "tty_read"))
943 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
946 /* We want to wait for the line discipline to sort out in this
948 ld = tty_ldisc_ref_wait(tty);
950 i = (ld->ops->read)(tty, file, buf, count);
955 inode->i_atime = current_fs_time(inode->i_sb);
959 void tty_write_unlock(struct tty_struct *tty)
961 mutex_unlock(&tty->atomic_write_lock);
962 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
965 int tty_write_lock(struct tty_struct *tty, int ndelay)
967 if (!mutex_trylock(&tty->atomic_write_lock)) {
970 if (mutex_lock_interruptible(&tty->atomic_write_lock))
977 * Split writes up in sane blocksizes to avoid
978 * denial-of-service type attacks
980 static inline ssize_t do_tty_write(
981 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
982 struct tty_struct *tty,
984 const char __user *buf,
987 ssize_t ret, written = 0;
990 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
995 * We chunk up writes into a temporary buffer. This
996 * simplifies low-level drivers immensely, since they
997 * don't have locking issues and user mode accesses.
999 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1002 * The default chunk-size is 2kB, because the NTTY
1003 * layer has problems with bigger chunks. It will
1004 * claim to be able to handle more characters than
1007 * FIXME: This can probably go away now except that 64K chunks
1008 * are too likely to fail unless switched to vmalloc...
1011 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1016 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1017 if (tty->write_cnt < chunk) {
1018 unsigned char *buf_chunk;
1023 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1028 kfree(tty->write_buf);
1029 tty->write_cnt = chunk;
1030 tty->write_buf = buf_chunk;
1033 /* Do the write .. */
1035 size_t size = count;
1039 if (copy_from_user(tty->write_buf, buf, size))
1041 ret = write(tty, file, tty->write_buf, size);
1050 if (signal_pending(current))
1055 struct inode *inode = file->f_path.dentry->d_inode;
1056 inode->i_mtime = current_fs_time(inode->i_sb);
1060 tty_write_unlock(tty);
1065 * tty_write_message - write a message to a certain tty, not just the console.
1066 * @tty: the destination tty_struct
1067 * @msg: the message to write
1069 * This is used for messages that need to be redirected to a specific tty.
1070 * We don't put it into the syslog queue right now maybe in the future if
1073 * We must still hold the BTM and test the CLOSING flag for the moment.
1076 void tty_write_message(struct tty_struct *tty, char *msg)
1079 mutex_lock(&tty->atomic_write_lock);
1081 if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) {
1083 tty->ops->write(tty, msg, strlen(msg));
1086 tty_write_unlock(tty);
1093 * tty_write - write method for tty device file
1094 * @file: tty file pointer
1095 * @buf: user data to write
1096 * @count: bytes to write
1099 * Write data to a tty device via the line discipline.
1102 * Locks the line discipline as required
1103 * Writes to the tty driver are serialized by the atomic_write_lock
1104 * and are then processed in chunks to the device. The line discipline
1105 * write method will not be invoked in parallel for each device.
1108 static ssize_t tty_write(struct file *file, const char __user *buf,
1109 size_t count, loff_t *ppos)
1111 struct inode *inode = file->f_path.dentry->d_inode;
1112 struct tty_struct *tty = file_tty(file);
1113 struct tty_ldisc *ld;
1116 if (tty_paranoia_check(tty, inode, "tty_write"))
1118 if (!tty || !tty->ops->write ||
1119 (test_bit(TTY_IO_ERROR, &tty->flags)))
1121 /* Short term debug to catch buggy drivers */
1122 if (tty->ops->write_room == NULL)
1123 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1125 ld = tty_ldisc_ref_wait(tty);
1126 if (!ld->ops->write)
1129 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1130 tty_ldisc_deref(ld);
1134 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1135 size_t count, loff_t *ppos)
1137 struct file *p = NULL;
1139 spin_lock(&redirect_lock);
1144 spin_unlock(&redirect_lock);
1148 res = vfs_write(p, buf, count, &p->f_pos);
1152 return tty_write(file, buf, count, ppos);
1155 static char ptychar[] = "pqrstuvwxyzabcde";
1158 * pty_line_name - generate name for a pty
1159 * @driver: the tty driver in use
1160 * @index: the minor number
1161 * @p: output buffer of at least 6 bytes
1163 * Generate a name from a driver reference and write it to the output
1168 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1170 int i = index + driver->name_base;
1171 /* ->name is initialized to "ttyp", but "tty" is expected */
1172 sprintf(p, "%s%c%x",
1173 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1174 ptychar[i >> 4 & 0xf], i & 0xf);
1178 * tty_line_name - generate name for a tty
1179 * @driver: the tty driver in use
1180 * @index: the minor number
1181 * @p: output buffer of at least 7 bytes
1183 * Generate a name from a driver reference and write it to the output
1188 static void tty_line_name(struct tty_driver *driver, int index, char *p)
1190 sprintf(p, "%s%d", driver->name, index + driver->name_base);
1194 * tty_driver_lookup_tty() - find an existing tty, if any
1195 * @driver: the driver for the tty
1196 * @idx: the minor number
1198 * Return the tty, if found or ERR_PTR() otherwise.
1200 * Locking: tty_mutex must be held. If tty is found, the mutex must
1201 * be held until the 'fast-open' is also done. Will change once we
1202 * have refcounting in the driver and per driver locking
1204 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1205 struct inode *inode, int idx)
1207 struct tty_struct *tty;
1209 if (driver->ops->lookup)
1210 return driver->ops->lookup(driver, inode, idx);
1212 tty = driver->ttys[idx];
1217 * tty_init_termios - helper for termios setup
1218 * @tty: the tty to set up
1220 * Initialise the termios structures for this tty. Thus runs under
1221 * the tty_mutex currently so we can be relaxed about ordering.
1224 int tty_init_termios(struct tty_struct *tty)
1226 struct ktermios *tp;
1227 int idx = tty->index;
1229 tp = tty->driver->termios[idx];
1231 tp = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
1234 memcpy(tp, &tty->driver->init_termios,
1235 sizeof(struct ktermios));
1236 tty->driver->termios[idx] = tp;
1239 tty->termios_locked = tp + 1;
1241 /* Compatibility until drivers always set this */
1242 tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
1243 tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
1246 EXPORT_SYMBOL_GPL(tty_init_termios);
1249 * tty_driver_install_tty() - install a tty entry in the driver
1250 * @driver: the driver for the tty
1253 * Install a tty object into the driver tables. The tty->index field
1254 * will be set by the time this is called. This method is responsible
1255 * for ensuring any need additional structures are allocated and
1258 * Locking: tty_mutex for now
1260 static int tty_driver_install_tty(struct tty_driver *driver,
1261 struct tty_struct *tty)
1263 int idx = tty->index;
1266 if (driver->ops->install) {
1267 ret = driver->ops->install(driver, tty);
1271 if (tty_init_termios(tty) == 0) {
1272 tty_driver_kref_get(driver);
1274 driver->ttys[idx] = tty;
1281 * tty_driver_remove_tty() - remove a tty from the driver tables
1282 * @driver: the driver for the tty
1283 * @idx: the minor number
1285 * Remvoe a tty object from the driver tables. The tty->index field
1286 * will be set by the time this is called.
1288 * Locking: tty_mutex for now
1290 static void tty_driver_remove_tty(struct tty_driver *driver,
1291 struct tty_struct *tty)
1293 if (driver->ops->remove)
1294 driver->ops->remove(driver, tty);
1296 driver->ttys[tty->index] = NULL;
1300 * tty_reopen() - fast re-open of an open tty
1301 * @tty - the tty to open
1303 * Return 0 on success, -errno on error.
1305 * Locking: tty_mutex must be held from the time the tty was found
1306 * till this open completes.
1308 static int tty_reopen(struct tty_struct *tty)
1310 struct tty_driver *driver = tty->driver;
1312 if (test_bit(TTY_CLOSING, &tty->flags))
1315 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1316 driver->subtype == PTY_TYPE_MASTER) {
1318 * special case for PTY masters: only one open permitted,
1319 * and the slave side open count is incremented as well.
1327 tty->driver = driver; /* N.B. why do this every time?? */
1329 mutex_lock(&tty->ldisc_mutex);
1330 WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
1331 mutex_unlock(&tty->ldisc_mutex);
1337 * tty_init_dev - initialise a tty device
1338 * @driver: tty driver we are opening a device on
1339 * @idx: device index
1340 * @ret_tty: returned tty structure
1341 * @first_ok: ok to open a new device (used by ptmx)
1343 * Prepare a tty device. This may not be a "new" clean device but
1344 * could also be an active device. The pty drivers require special
1345 * handling because of this.
1348 * The function is called under the tty_mutex, which
1349 * protects us from the tty struct or driver itself going away.
1351 * On exit the tty device has the line discipline attached and
1352 * a reference count of 1. If a pair was created for pty/tty use
1353 * and the other was a pty master then it too has a reference count of 1.
1355 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1356 * failed open. The new code protects the open with a mutex, so it's
1357 * really quite straightforward. The mutex locking can probably be
1358 * relaxed for the (most common) case of reopening a tty.
1361 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx,
1364 struct tty_struct *tty;
1367 /* Check if pty master is being opened multiple times */
1368 if (driver->subtype == PTY_TYPE_MASTER &&
1369 (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok) {
1370 return ERR_PTR(-EIO);
1374 * First time open is complex, especially for PTY devices.
1375 * This code guarantees that either everything succeeds and the
1376 * TTY is ready for operation, or else the table slots are vacated
1377 * and the allocated memory released. (Except that the termios
1378 * and locked termios may be retained.)
1381 if (!try_module_get(driver->owner))
1382 return ERR_PTR(-ENODEV);
1384 tty = alloc_tty_struct();
1387 initialize_tty_struct(tty, driver, idx);
1389 retval = tty_driver_install_tty(driver, tty);
1391 free_tty_struct(tty);
1392 module_put(driver->owner);
1393 return ERR_PTR(retval);
1397 * Structures all installed ... call the ldisc open routines.
1398 * If we fail here just call release_tty to clean up. No need
1399 * to decrement the use counts, as release_tty doesn't care.
1401 retval = tty_ldisc_setup(tty, tty->link);
1403 goto release_mem_out;
1407 module_put(driver->owner);
1408 return ERR_PTR(-ENOMEM);
1410 /* call the tty release_tty routine to clean out this slot */
1412 if (printk_ratelimit())
1413 printk(KERN_INFO "tty_init_dev: ldisc open failed, "
1414 "clearing slot %d\n", idx);
1415 release_tty(tty, idx);
1416 return ERR_PTR(retval);
1419 void tty_free_termios(struct tty_struct *tty)
1421 struct ktermios *tp;
1422 int idx = tty->index;
1423 /* Kill this flag and push into drivers for locking etc */
1424 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
1425 /* FIXME: Locking on ->termios array */
1427 tty->driver->termios[idx] = NULL;
1431 EXPORT_SYMBOL(tty_free_termios);
1433 void tty_shutdown(struct tty_struct *tty)
1435 tty_driver_remove_tty(tty->driver, tty);
1436 tty_free_termios(tty);
1438 EXPORT_SYMBOL(tty_shutdown);
1441 * release_one_tty - release tty structure memory
1442 * @kref: kref of tty we are obliterating
1444 * Releases memory associated with a tty structure, and clears out the
1445 * driver table slots. This function is called when a device is no longer
1446 * in use. It also gets called when setup of a device fails.
1449 * tty_mutex - sometimes only
1450 * takes the file list lock internally when working on the list
1451 * of ttys that the driver keeps.
1453 * This method gets called from a work queue so that the driver private
1454 * cleanup ops can sleep (needed for USB at least)
1456 static void release_one_tty(struct work_struct *work)
1458 struct tty_struct *tty =
1459 container_of(work, struct tty_struct, hangup_work);
1460 struct tty_driver *driver = tty->driver;
1462 if (tty->ops->cleanup)
1463 tty->ops->cleanup(tty);
1466 tty_driver_kref_put(driver);
1467 module_put(driver->owner);
1469 spin_lock(&tty_files_lock);
1470 list_del_init(&tty->tty_files);
1471 spin_unlock(&tty_files_lock);
1474 put_pid(tty->session);
1475 free_tty_struct(tty);
1478 static void queue_release_one_tty(struct kref *kref)
1480 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1482 if (tty->ops->shutdown)
1483 tty->ops->shutdown(tty);
1487 /* The hangup queue is now free so we can reuse it rather than
1488 waste a chunk of memory for each port */
1489 INIT_WORK(&tty->hangup_work, release_one_tty);
1490 schedule_work(&tty->hangup_work);
1494 * tty_kref_put - release a tty kref
1497 * Release a reference to a tty device and if need be let the kref
1498 * layer destruct the object for us
1501 void tty_kref_put(struct tty_struct *tty)
1504 kref_put(&tty->kref, queue_release_one_tty);
1506 EXPORT_SYMBOL(tty_kref_put);
1509 * release_tty - release tty structure memory
1511 * Release both @tty and a possible linked partner (think pty pair),
1512 * and decrement the refcount of the backing module.
1515 * tty_mutex - sometimes only
1516 * takes the file list lock internally when working on the list
1517 * of ttys that the driver keeps.
1518 * FIXME: should we require tty_mutex is held here ??
1521 static void release_tty(struct tty_struct *tty, int idx)
1523 /* This should always be true but check for the moment */
1524 WARN_ON(tty->index != idx);
1527 tty_kref_put(tty->link);
1532 * tty_release - vfs callback for close
1533 * @inode: inode of tty
1534 * @filp: file pointer for handle to tty
1536 * Called the last time each file handle is closed that references
1537 * this tty. There may however be several such references.
1540 * Takes bkl. See tty_release_dev
1542 * Even releasing the tty structures is a tricky business.. We have
1543 * to be very careful that the structures are all released at the
1544 * same time, as interrupts might otherwise get the wrong pointers.
1546 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1547 * lead to double frees or releasing memory still in use.
1550 int tty_release(struct inode *inode, struct file *filp)
1552 struct tty_struct *tty = file_tty(filp);
1553 struct tty_struct *o_tty;
1554 int pty_master, tty_closing, o_tty_closing, do_sleep;
1559 if (tty_paranoia_check(tty, inode, "tty_release_dev"))
1563 check_tty_count(tty, "tty_release_dev");
1565 __tty_fasync(-1, filp, 0);
1568 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1569 tty->driver->subtype == PTY_TYPE_MASTER);
1570 devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
1573 #ifdef TTY_PARANOIA_CHECK
1574 if (idx < 0 || idx >= tty->driver->num) {
1575 printk(KERN_DEBUG "tty_release_dev: bad idx when trying to "
1576 "free (%s)\n", tty->name);
1581 if (tty != tty->driver->ttys[idx]) {
1583 printk(KERN_DEBUG "tty_release_dev: driver.table[%d] not tty "
1584 "for (%s)\n", idx, tty->name);
1587 if (tty->termios != tty->driver->termios[idx]) {
1589 printk(KERN_DEBUG "tty_release_dev: driver.termios[%d] not termios "
1597 #ifdef TTY_DEBUG_HANGUP
1598 printk(KERN_DEBUG "tty_release_dev of %s (tty count=%d)...",
1599 tty_name(tty, buf), tty->count);
1602 #ifdef TTY_PARANOIA_CHECK
1603 if (tty->driver->other &&
1604 !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
1605 if (o_tty != tty->driver->other->ttys[idx]) {
1607 printk(KERN_DEBUG "tty_release_dev: other->table[%d] "
1608 "not o_tty for (%s)\n",
1612 if (o_tty->termios != tty->driver->other->termios[idx]) {
1614 printk(KERN_DEBUG "tty_release_dev: other->termios[%d] "
1615 "not o_termios for (%s)\n",
1619 if (o_tty->link != tty) {
1621 printk(KERN_DEBUG "tty_release_dev: bad pty pointers\n");
1626 if (tty->ops->close)
1627 tty->ops->close(tty, filp);
1631 * Sanity check: if tty->count is going to zero, there shouldn't be
1632 * any waiters on tty->read_wait or tty->write_wait. We test the
1633 * wait queues and kick everyone out _before_ actually starting to
1634 * close. This ensures that we won't block while releasing the tty
1637 * The test for the o_tty closing is necessary, since the master and
1638 * slave sides may close in any order. If the slave side closes out
1639 * first, its count will be one, since the master side holds an open.
1640 * Thus this test wouldn't be triggered at the time the slave closes,
1643 * Note that it's possible for the tty to be opened again while we're
1644 * flushing out waiters. By recalculating the closing flags before
1645 * each iteration we avoid any problems.
1648 /* Guard against races with tty->count changes elsewhere and
1649 opens on /dev/tty */
1651 mutex_lock(&tty_mutex);
1653 tty_closing = tty->count <= 1;
1654 o_tty_closing = o_tty &&
1655 (o_tty->count <= (pty_master ? 1 : 0));
1659 if (waitqueue_active(&tty->read_wait)) {
1660 wake_up_poll(&tty->read_wait, POLLIN);
1663 if (waitqueue_active(&tty->write_wait)) {
1664 wake_up_poll(&tty->write_wait, POLLOUT);
1668 if (o_tty_closing) {
1669 if (waitqueue_active(&o_tty->read_wait)) {
1670 wake_up_poll(&o_tty->read_wait, POLLIN);
1673 if (waitqueue_active(&o_tty->write_wait)) {
1674 wake_up_poll(&o_tty->write_wait, POLLOUT);
1681 printk(KERN_WARNING "tty_release_dev: %s: read/write wait queue "
1682 "active!\n", tty_name(tty, buf));
1684 mutex_unlock(&tty_mutex);
1689 * The closing flags are now consistent with the open counts on
1690 * both sides, and we've completed the last operation that could
1691 * block, so it's safe to proceed with closing.
1694 if (--o_tty->count < 0) {
1695 printk(KERN_WARNING "tty_release_dev: bad pty slave count "
1697 o_tty->count, tty_name(o_tty, buf));
1701 if (--tty->count < 0) {
1702 printk(KERN_WARNING "tty_release_dev: bad tty->count (%d) for %s\n",
1703 tty->count, tty_name(tty, buf));
1708 * We've decremented tty->count, so we need to remove this file
1709 * descriptor off the tty->tty_files list; this serves two
1711 * - check_tty_count sees the correct number of file descriptors
1712 * associated with this tty.
1713 * - do_tty_hangup no longer sees this file descriptor as
1714 * something that needs to be handled for hangups.
1719 * Perform some housekeeping before deciding whether to return.
1721 * Set the TTY_CLOSING flag if this was the last open. In the
1722 * case of a pty we may have to wait around for the other side
1723 * to close, and TTY_CLOSING makes sure we can't be reopened.
1726 set_bit(TTY_CLOSING, &tty->flags);
1728 set_bit(TTY_CLOSING, &o_tty->flags);
1731 * If _either_ side is closing, make sure there aren't any
1732 * processes that still think tty or o_tty is their controlling
1735 if (tty_closing || o_tty_closing) {
1736 read_lock(&tasklist_lock);
1737 session_clear_tty(tty->session);
1739 session_clear_tty(o_tty->session);
1740 read_unlock(&tasklist_lock);
1743 mutex_unlock(&tty_mutex);
1745 /* check whether both sides are closing ... */
1746 if (!tty_closing || (o_tty && !o_tty_closing)) {
1751 #ifdef TTY_DEBUG_HANGUP
1752 printk(KERN_DEBUG "freeing tty structure...");
1755 * Ask the line discipline code to release its structures
1757 tty_ldisc_release(tty, o_tty);
1759 * The release_tty function takes care of the details of clearing
1760 * the slots and preserving the termios structure.
1762 release_tty(tty, idx);
1764 /* Make this pty number available for reallocation */
1766 devpts_kill_index(inode, idx);
1772 * tty_open - open a tty device
1773 * @inode: inode of device file
1774 * @filp: file pointer to tty
1776 * tty_open and tty_release keep up the tty count that contains the
1777 * number of opens done on a tty. We cannot use the inode-count, as
1778 * different inodes might point to the same tty.
1780 * Open-counting is needed for pty masters, as well as for keeping
1781 * track of serial lines: DTR is dropped when the last close happens.
1782 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1784 * The termios state of a pty is reset on first open so that
1785 * settings don't persist across reuse.
1787 * Locking: tty_mutex protects tty, get_tty_driver and tty_init_dev work.
1788 * tty->count should protect the rest.
1789 * ->siglock protects ->signal/->sighand
1792 static int tty_open(struct inode *inode, struct file *filp)
1794 struct tty_struct *tty = NULL;
1796 struct tty_driver *driver;
1798 dev_t device = inode->i_rdev;
1799 unsigned saved_flags = filp->f_flags;
1801 nonseekable_open(inode, filp);
1804 noctty = filp->f_flags & O_NOCTTY;
1808 mutex_lock(&tty_mutex);
1811 if (device == MKDEV(TTYAUX_MAJOR, 0)) {
1812 tty = get_current_tty();
1815 mutex_unlock(&tty_mutex);
1818 driver = tty_driver_kref_get(tty->driver);
1820 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1822 /* FIXME: Should we take a driver reference ? */
1827 if (device == MKDEV(TTY_MAJOR, 0)) {
1828 extern struct tty_driver *console_driver;
1829 driver = tty_driver_kref_get(console_driver);
1835 if (device == MKDEV(TTYAUX_MAJOR, 1)) {
1836 struct tty_driver *console_driver = console_device(&index);
1837 if (console_driver) {
1838 driver = tty_driver_kref_get(console_driver);
1840 /* Don't let /dev/console block */
1841 filp->f_flags |= O_NONBLOCK;
1847 mutex_unlock(&tty_mutex);
1851 driver = get_tty_driver(device, &index);
1854 mutex_unlock(&tty_mutex);
1859 /* check whether we're reopening an existing tty */
1860 tty = tty_driver_lookup_tty(driver, inode, index);
1864 mutex_unlock(&tty_mutex);
1865 return PTR_ERR(tty);
1870 retval = tty_reopen(tty);
1872 tty = ERR_PTR(retval);
1874 tty = tty_init_dev(driver, index, 0);
1876 mutex_unlock(&tty_mutex);
1877 tty_driver_kref_put(driver);
1880 return PTR_ERR(tty);
1883 retval = tty_add_file(tty, filp);
1889 check_tty_count(tty, "tty_open");
1890 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1891 tty->driver->subtype == PTY_TYPE_MASTER)
1893 #ifdef TTY_DEBUG_HANGUP
1894 printk(KERN_DEBUG "opening %s...", tty->name);
1898 retval = tty->ops->open(tty, filp);
1902 filp->f_flags = saved_flags;
1904 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
1905 !capable(CAP_SYS_ADMIN))
1909 #ifdef TTY_DEBUG_HANGUP
1910 printk(KERN_DEBUG "error %d in opening %s...", retval,
1913 tty_unlock(); /* need to call tty_release without BTM */
1914 tty_release(inode, filp);
1915 if (retval != -ERESTARTSYS)
1918 if (signal_pending(current))
1923 * Need to reset f_op in case a hangup happened.
1926 if (filp->f_op == &hung_up_tty_fops)
1927 filp->f_op = &tty_fops;
1934 mutex_lock(&tty_mutex);
1936 spin_lock_irq(¤t->sighand->siglock);
1938 current->signal->leader &&
1939 !current->signal->tty &&
1940 tty->session == NULL)
1941 __proc_set_tty(current, tty);
1942 spin_unlock_irq(¤t->sighand->siglock);
1944 mutex_unlock(&tty_mutex);
1951 * tty_poll - check tty status
1952 * @filp: file being polled
1953 * @wait: poll wait structures to update
1955 * Call the line discipline polling method to obtain the poll
1956 * status of the device.
1958 * Locking: locks called line discipline but ldisc poll method
1959 * may be re-entered freely by other callers.
1962 static unsigned int tty_poll(struct file *filp, poll_table *wait)
1964 struct tty_struct *tty = file_tty(filp);
1965 struct tty_ldisc *ld;
1968 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll"))
1971 ld = tty_ldisc_ref_wait(tty);
1973 ret = (ld->ops->poll)(tty, filp, wait);
1974 tty_ldisc_deref(ld);
1978 static int __tty_fasync(int fd, struct file *filp, int on)
1980 struct tty_struct *tty = file_tty(filp);
1981 unsigned long flags;
1984 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
1987 retval = fasync_helper(fd, filp, on, &tty->fasync);
1994 if (!waitqueue_active(&tty->read_wait))
1995 tty->minimum_to_wake = 1;
1996 spin_lock_irqsave(&tty->ctrl_lock, flags);
1999 type = PIDTYPE_PGID;
2001 pid = task_pid(current);
2005 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2006 retval = __f_setown(filp, pid, type, 0);
2011 if (!tty->fasync && !waitqueue_active(&tty->read_wait))
2012 tty->minimum_to_wake = N_TTY_BUF_SIZE;
2019 static int tty_fasync(int fd, struct file *filp, int on)
2023 retval = __tty_fasync(fd, filp, on);
2029 * tiocsti - fake input character
2030 * @tty: tty to fake input into
2031 * @p: pointer to character
2033 * Fake input to a tty device. Does the necessary locking and
2036 * FIXME: does not honour flow control ??
2039 * Called functions take tty_ldisc_lock
2040 * current->signal->tty check is safe without locks
2042 * FIXME: may race normal receive processing
2045 static int tiocsti(struct tty_struct *tty, char __user *p)
2048 struct tty_ldisc *ld;
2050 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2052 if (get_user(ch, p))
2054 tty_audit_tiocsti(tty, ch);
2055 ld = tty_ldisc_ref_wait(tty);
2056 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2057 tty_ldisc_deref(ld);
2062 * tiocgwinsz - implement window query ioctl
2064 * @arg: user buffer for result
2066 * Copies the kernel idea of the window size into the user buffer.
2068 * Locking: tty->termios_mutex is taken to ensure the winsize data
2072 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2076 mutex_lock(&tty->termios_mutex);
2077 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2078 mutex_unlock(&tty->termios_mutex);
2080 return err ? -EFAULT: 0;
2084 * tty_do_resize - resize event
2085 * @tty: tty being resized
2086 * @rows: rows (character)
2087 * @cols: cols (character)
2089 * Update the termios variables and send the necessary signals to
2090 * peform a terminal resize correctly
2093 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2096 unsigned long flags;
2099 mutex_lock(&tty->termios_mutex);
2100 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2102 /* Get the PID values and reference them so we can
2103 avoid holding the tty ctrl lock while sending signals */
2104 spin_lock_irqsave(&tty->ctrl_lock, flags);
2105 pgrp = get_pid(tty->pgrp);
2106 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2109 kill_pgrp(pgrp, SIGWINCH, 1);
2114 mutex_unlock(&tty->termios_mutex);
2119 * tiocswinsz - implement window size set ioctl
2120 * @tty; tty side of tty
2121 * @arg: user buffer for result
2123 * Copies the user idea of the window size to the kernel. Traditionally
2124 * this is just advisory information but for the Linux console it
2125 * actually has driver level meaning and triggers a VC resize.
2128 * Driver dependant. The default do_resize method takes the
2129 * tty termios mutex and ctrl_lock. The console takes its own lock
2130 * then calls into the default method.
2133 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2135 struct winsize tmp_ws;
2136 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2139 if (tty->ops->resize)
2140 return tty->ops->resize(tty, &tmp_ws);
2142 return tty_do_resize(tty, &tmp_ws);
2146 * tioccons - allow admin to move logical console
2147 * @file: the file to become console
2149 * Allow the adminstrator to move the redirected console device
2151 * Locking: uses redirect_lock to guard the redirect information
2154 static int tioccons(struct file *file)
2156 if (!capable(CAP_SYS_ADMIN))
2158 if (file->f_op->write == redirected_tty_write) {
2160 spin_lock(&redirect_lock);
2163 spin_unlock(&redirect_lock);
2168 spin_lock(&redirect_lock);
2170 spin_unlock(&redirect_lock);
2175 spin_unlock(&redirect_lock);
2180 * fionbio - non blocking ioctl
2181 * @file: file to set blocking value
2182 * @p: user parameter
2184 * Historical tty interfaces had a blocking control ioctl before
2185 * the generic functionality existed. This piece of history is preserved
2186 * in the expected tty API of posix OS's.
2188 * Locking: none, the open file handle ensures it won't go away.
2191 static int fionbio(struct file *file, int __user *p)
2195 if (get_user(nonblock, p))
2198 spin_lock(&file->f_lock);
2200 file->f_flags |= O_NONBLOCK;
2202 file->f_flags &= ~O_NONBLOCK;
2203 spin_unlock(&file->f_lock);
2208 * tiocsctty - set controlling tty
2209 * @tty: tty structure
2210 * @arg: user argument
2212 * This ioctl is used to manage job control. It permits a session
2213 * leader to set this tty as the controlling tty for the session.
2216 * Takes tty_mutex() to protect tty instance
2217 * Takes tasklist_lock internally to walk sessions
2218 * Takes ->siglock() when updating signal->tty
2221 static int tiocsctty(struct tty_struct *tty, int arg)
2224 if (current->signal->leader && (task_session(current) == tty->session))
2227 mutex_lock(&tty_mutex);
2229 * The process must be a session leader and
2230 * not have a controlling tty already.
2232 if (!current->signal->leader || current->signal->tty) {
2239 * This tty is already the controlling
2240 * tty for another session group!
2242 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2246 read_lock(&tasklist_lock);
2247 session_clear_tty(tty->session);
2248 read_unlock(&tasklist_lock);
2254 proc_set_tty(current, tty);
2256 mutex_unlock(&tty_mutex);
2261 * tty_get_pgrp - return a ref counted pgrp pid
2264 * Returns a refcounted instance of the pid struct for the process
2265 * group controlling the tty.
2268 struct pid *tty_get_pgrp(struct tty_struct *tty)
2270 unsigned long flags;
2273 spin_lock_irqsave(&tty->ctrl_lock, flags);
2274 pgrp = get_pid(tty->pgrp);
2275 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2279 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2282 * tiocgpgrp - get process group
2283 * @tty: tty passed by user
2284 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2287 * Obtain the process group of the tty. If there is no process group
2290 * Locking: none. Reference to current->signal->tty is safe.
2293 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2298 * (tty == real_tty) is a cheap way of
2299 * testing if the tty is NOT a master pty.
2301 if (tty == real_tty && current->signal->tty != real_tty)
2303 pid = tty_get_pgrp(real_tty);
2304 ret = put_user(pid_vnr(pid), p);
2310 * tiocspgrp - attempt to set process group
2311 * @tty: tty passed by user
2312 * @real_tty: tty side device matching tty passed by user
2315 * Set the process group of the tty to the session passed. Only
2316 * permitted where the tty session is our session.
2318 * Locking: RCU, ctrl lock
2321 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2325 int retval = tty_check_change(real_tty);
2326 unsigned long flags;
2332 if (!current->signal->tty ||
2333 (current->signal->tty != real_tty) ||
2334 (real_tty->session != task_session(current)))
2336 if (get_user(pgrp_nr, p))
2341 pgrp = find_vpid(pgrp_nr);
2346 if (session_of_pgrp(pgrp) != task_session(current))
2349 spin_lock_irqsave(&tty->ctrl_lock, flags);
2350 put_pid(real_tty->pgrp);
2351 real_tty->pgrp = get_pid(pgrp);
2352 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2359 * tiocgsid - get session id
2360 * @tty: tty passed by user
2361 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2362 * @p: pointer to returned session id
2364 * Obtain the session id of the tty. If there is no session
2367 * Locking: none. Reference to current->signal->tty is safe.
2370 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2373 * (tty == real_tty) is a cheap way of
2374 * testing if the tty is NOT a master pty.
2376 if (tty == real_tty && current->signal->tty != real_tty)
2378 if (!real_tty->session)
2380 return put_user(pid_vnr(real_tty->session), p);
2384 * tiocsetd - set line discipline
2386 * @p: pointer to user data
2388 * Set the line discipline according to user request.
2390 * Locking: see tty_set_ldisc, this function is just a helper
2393 static int tiocsetd(struct tty_struct *tty, int __user *p)
2398 if (get_user(ldisc, p))
2401 ret = tty_set_ldisc(tty, ldisc);
2407 * send_break - performed time break
2408 * @tty: device to break on
2409 * @duration: timeout in mS
2411 * Perform a timed break on hardware that lacks its own driver level
2412 * timed break functionality.
2415 * atomic_write_lock serializes
2419 static int send_break(struct tty_struct *tty, unsigned int duration)
2423 if (tty->ops->break_ctl == NULL)
2426 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2427 retval = tty->ops->break_ctl(tty, duration);
2429 /* Do the work ourselves */
2430 if (tty_write_lock(tty, 0) < 0)
2432 retval = tty->ops->break_ctl(tty, -1);
2435 if (!signal_pending(current))
2436 msleep_interruptible(duration);
2437 retval = tty->ops->break_ctl(tty, 0);
2439 tty_write_unlock(tty);
2440 if (signal_pending(current))
2447 * tty_tiocmget - get modem status
2449 * @file: user file pointer
2450 * @p: pointer to result
2452 * Obtain the modem status bits from the tty driver if the feature
2453 * is supported. Return -EINVAL if it is not available.
2455 * Locking: none (up to the driver)
2458 static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p)
2460 int retval = -EINVAL;
2462 if (tty->ops->tiocmget) {
2463 retval = tty->ops->tiocmget(tty, file);
2466 retval = put_user(retval, p);
2472 * tty_tiocmset - set modem status
2474 * @file: user file pointer
2475 * @cmd: command - clear bits, set bits or set all
2476 * @p: pointer to desired bits
2478 * Set the modem status bits from the tty driver if the feature
2479 * is supported. Return -EINVAL if it is not available.
2481 * Locking: none (up to the driver)
2484 static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int cmd,
2488 unsigned int set, clear, val;
2490 if (tty->ops->tiocmset == NULL)
2493 retval = get_user(val, p);
2509 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2510 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2511 return tty->ops->tiocmset(tty, file, set, clear);
2514 struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2516 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2517 tty->driver->subtype == PTY_TYPE_MASTER)
2521 EXPORT_SYMBOL(tty_pair_get_tty);
2523 struct tty_struct *tty_pair_get_pty(struct tty_struct *tty)
2525 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2526 tty->driver->subtype == PTY_TYPE_MASTER)
2530 EXPORT_SYMBOL(tty_pair_get_pty);
2533 * Split this up, as gcc can choke on it otherwise..
2535 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2537 struct tty_struct *tty = file_tty(file);
2538 struct tty_struct *real_tty;
2539 void __user *p = (void __user *)arg;
2541 struct tty_ldisc *ld;
2542 struct inode *inode = file->f_dentry->d_inode;
2544 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2547 real_tty = tty_pair_get_tty(tty);
2550 * Factor out some common prep work
2558 retval = tty_check_change(tty);
2561 if (cmd != TIOCCBRK) {
2562 tty_wait_until_sent(tty, 0);
2563 if (signal_pending(current))
2574 return tiocsti(tty, p);
2576 return tiocgwinsz(real_tty, p);
2578 return tiocswinsz(real_tty, p);
2580 return real_tty != tty ? -EINVAL : tioccons(file);
2582 return fionbio(file, p);
2584 set_bit(TTY_EXCLUSIVE, &tty->flags);
2587 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2590 if (current->signal->tty != tty)
2595 return tiocsctty(tty, arg);
2597 return tiocgpgrp(tty, real_tty, p);
2599 return tiocspgrp(tty, real_tty, p);
2601 return tiocgsid(tty, real_tty, p);
2603 return put_user(tty->ldisc->ops->num, (int __user *)p);
2605 return tiocsetd(tty, p);
2609 case TIOCSBRK: /* Turn break on, unconditionally */
2610 if (tty->ops->break_ctl)
2611 return tty->ops->break_ctl(tty, -1);
2613 case TIOCCBRK: /* Turn break off, unconditionally */
2614 if (tty->ops->break_ctl)
2615 return tty->ops->break_ctl(tty, 0);
2617 case TCSBRK: /* SVID version: non-zero arg --> no break */
2618 /* non-zero arg means wait for all output data
2619 * to be sent (performed above) but don't send break.
2620 * This is used by the tcdrain() termios function.
2623 return send_break(tty, 250);
2625 case TCSBRKP: /* support for POSIX tcsendbreak() */
2626 return send_break(tty, arg ? arg*100 : 250);
2629 return tty_tiocmget(tty, file, p);
2633 return tty_tiocmset(tty, file, cmd, p);
2638 /* flush tty buffer and allow ldisc to process ioctl */
2639 tty_buffer_flush(tty);
2644 if (tty->ops->ioctl) {
2645 retval = (tty->ops->ioctl)(tty, file, cmd, arg);
2646 if (retval != -ENOIOCTLCMD)
2649 ld = tty_ldisc_ref_wait(tty);
2651 if (ld->ops->ioctl) {
2652 retval = ld->ops->ioctl(tty, file, cmd, arg);
2653 if (retval == -ENOIOCTLCMD)
2656 tty_ldisc_deref(ld);
2660 #ifdef CONFIG_COMPAT
2661 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2664 struct inode *inode = file->f_dentry->d_inode;
2665 struct tty_struct *tty = file_tty(file);
2666 struct tty_ldisc *ld;
2667 int retval = -ENOIOCTLCMD;
2669 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2672 if (tty->ops->compat_ioctl) {
2673 retval = (tty->ops->compat_ioctl)(tty, file, cmd, arg);
2674 if (retval != -ENOIOCTLCMD)
2678 ld = tty_ldisc_ref_wait(tty);
2679 if (ld->ops->compat_ioctl)
2680 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2681 tty_ldisc_deref(ld);
2688 * This implements the "Secure Attention Key" --- the idea is to
2689 * prevent trojan horses by killing all processes associated with this
2690 * tty when the user hits the "Secure Attention Key". Required for
2691 * super-paranoid applications --- see the Orange Book for more details.
2693 * This code could be nicer; ideally it should send a HUP, wait a few
2694 * seconds, then send a INT, and then a KILL signal. But you then
2695 * have to coordinate with the init process, since all processes associated
2696 * with the current tty must be dead before the new getty is allowed
2699 * Now, if it would be correct ;-/ The current code has a nasty hole -
2700 * it doesn't catch files in flight. We may send the descriptor to ourselves
2701 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2703 * Nasty bug: do_SAK is being called in interrupt context. This can
2704 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2706 void __do_SAK(struct tty_struct *tty)
2711 struct task_struct *g, *p;
2712 struct pid *session;
2715 struct fdtable *fdt;
2719 session = tty->session;
2721 tty_ldisc_flush(tty);
2723 tty_driver_flush_buffer(tty);
2725 read_lock(&tasklist_lock);
2726 /* Kill the entire session */
2727 do_each_pid_task(session, PIDTYPE_SID, p) {
2728 printk(KERN_NOTICE "SAK: killed process %d"
2729 " (%s): task_session(p)==tty->session\n",
2730 task_pid_nr(p), p->comm);
2731 send_sig(SIGKILL, p, 1);
2732 } while_each_pid_task(session, PIDTYPE_SID, p);
2733 /* Now kill any processes that happen to have the
2736 do_each_thread(g, p) {
2737 if (p->signal->tty == tty) {
2738 printk(KERN_NOTICE "SAK: killed process %d"
2739 " (%s): task_session(p)==tty->session\n",
2740 task_pid_nr(p), p->comm);
2741 send_sig(SIGKILL, p, 1);
2747 * We don't take a ref to the file, so we must
2748 * hold ->file_lock instead.
2750 spin_lock(&p->files->file_lock);
2751 fdt = files_fdtable(p->files);
2752 for (i = 0; i < fdt->max_fds; i++) {
2753 filp = fcheck_files(p->files, i);
2756 if (filp->f_op->read == tty_read &&
2757 file_tty(filp) == tty) {
2758 printk(KERN_NOTICE "SAK: killed process %d"
2759 " (%s): fd#%d opened to the tty\n",
2760 task_pid_nr(p), p->comm, i);
2761 force_sig(SIGKILL, p);
2765 spin_unlock(&p->files->file_lock);
2768 } while_each_thread(g, p);
2769 read_unlock(&tasklist_lock);
2773 static void do_SAK_work(struct work_struct *work)
2775 struct tty_struct *tty =
2776 container_of(work, struct tty_struct, SAK_work);
2781 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2782 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2783 * the values which we write to it will be identical to the values which it
2784 * already has. --akpm
2786 void do_SAK(struct tty_struct *tty)
2790 schedule_work(&tty->SAK_work);
2793 EXPORT_SYMBOL(do_SAK);
2795 static int dev_match_devt(struct device *dev, void *data)
2798 return dev->devt == *devt;
2801 /* Must put_device() after it's unused! */
2802 static struct device *tty_get_device(struct tty_struct *tty)
2804 dev_t devt = tty_devnum(tty);
2805 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
2810 * initialize_tty_struct
2811 * @tty: tty to initialize
2813 * This subroutine initializes a tty structure that has been newly
2816 * Locking: none - tty in question must not be exposed at this point
2819 void initialize_tty_struct(struct tty_struct *tty,
2820 struct tty_driver *driver, int idx)
2822 memset(tty, 0, sizeof(struct tty_struct));
2823 kref_init(&tty->kref);
2824 tty->magic = TTY_MAGIC;
2825 tty_ldisc_init(tty);
2826 tty->session = NULL;
2828 tty->overrun_time = jiffies;
2829 tty->buf.head = tty->buf.tail = NULL;
2830 tty_buffer_init(tty);
2831 mutex_init(&tty->termios_mutex);
2832 mutex_init(&tty->ldisc_mutex);
2833 init_waitqueue_head(&tty->write_wait);
2834 init_waitqueue_head(&tty->read_wait);
2835 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2836 mutex_init(&tty->atomic_read_lock);
2837 mutex_init(&tty->atomic_write_lock);
2838 mutex_init(&tty->output_lock);
2839 mutex_init(&tty->echo_lock);
2840 spin_lock_init(&tty->read_lock);
2841 spin_lock_init(&tty->ctrl_lock);
2842 INIT_LIST_HEAD(&tty->tty_files);
2843 INIT_WORK(&tty->SAK_work, do_SAK_work);
2845 tty->driver = driver;
2846 tty->ops = driver->ops;
2848 tty_line_name(driver, idx, tty->name);
2849 tty->dev = tty_get_device(tty);
2853 * tty_put_char - write one character to a tty
2857 * Write one byte to the tty using the provided put_char method
2858 * if present. Returns the number of characters successfully output.
2860 * Note: the specific put_char operation in the driver layer may go
2861 * away soon. Don't call it directly, use this method
2864 int tty_put_char(struct tty_struct *tty, unsigned char ch)
2866 if (tty->ops->put_char)
2867 return tty->ops->put_char(tty, ch);
2868 return tty->ops->write(tty, &ch, 1);
2870 EXPORT_SYMBOL_GPL(tty_put_char);
2872 struct class *tty_class;
2875 * tty_register_device - register a tty device
2876 * @driver: the tty driver that describes the tty device
2877 * @index: the index in the tty driver for this tty device
2878 * @device: a struct device that is associated with this tty device.
2879 * This field is optional, if there is no known struct device
2880 * for this tty device it can be set to NULL safely.
2882 * Returns a pointer to the struct device for this tty device
2883 * (or ERR_PTR(-EFOO) on error).
2885 * This call is required to be made to register an individual tty device
2886 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2887 * that bit is not set, this function should not be called by a tty
2893 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
2894 struct device *device)
2897 dev_t dev = MKDEV(driver->major, driver->minor_start) + index;
2899 if (index >= driver->num) {
2900 printk(KERN_ERR "Attempt to register invalid tty line number "
2902 return ERR_PTR(-EINVAL);
2905 if (driver->type == TTY_DRIVER_TYPE_PTY)
2906 pty_line_name(driver, index, name);
2908 tty_line_name(driver, index, name);
2910 return device_create(tty_class, device, dev, NULL, name);
2912 EXPORT_SYMBOL(tty_register_device);
2915 * tty_unregister_device - unregister a tty device
2916 * @driver: the tty driver that describes the tty device
2917 * @index: the index in the tty driver for this tty device
2919 * If a tty device is registered with a call to tty_register_device() then
2920 * this function must be called when the tty device is gone.
2925 void tty_unregister_device(struct tty_driver *driver, unsigned index)
2927 device_destroy(tty_class,
2928 MKDEV(driver->major, driver->minor_start) + index);
2930 EXPORT_SYMBOL(tty_unregister_device);
2932 struct tty_driver *alloc_tty_driver(int lines)
2934 struct tty_driver *driver;
2936 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
2938 kref_init(&driver->kref);
2939 driver->magic = TTY_DRIVER_MAGIC;
2940 driver->num = lines;
2941 /* later we'll move allocation of tables here */
2945 EXPORT_SYMBOL(alloc_tty_driver);
2947 static void destruct_tty_driver(struct kref *kref)
2949 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
2951 struct ktermios *tp;
2954 if (driver->flags & TTY_DRIVER_INSTALLED) {
2956 * Free the termios and termios_locked structures because
2957 * we don't want to get memory leaks when modular tty
2958 * drivers are removed from the kernel.
2960 for (i = 0; i < driver->num; i++) {
2961 tp = driver->termios[i];
2963 driver->termios[i] = NULL;
2966 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
2967 tty_unregister_device(driver, i);
2970 proc_tty_unregister_driver(driver);
2971 driver->ttys = NULL;
2972 driver->termios = NULL;
2974 cdev_del(&driver->cdev);
2979 void tty_driver_kref_put(struct tty_driver *driver)
2981 kref_put(&driver->kref, destruct_tty_driver);
2983 EXPORT_SYMBOL(tty_driver_kref_put);
2985 void tty_set_operations(struct tty_driver *driver,
2986 const struct tty_operations *op)
2990 EXPORT_SYMBOL(tty_set_operations);
2992 void put_tty_driver(struct tty_driver *d)
2994 tty_driver_kref_put(d);
2996 EXPORT_SYMBOL(put_tty_driver);
2999 * Called by a tty driver to register itself.
3001 int tty_register_driver(struct tty_driver *driver)
3008 if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) {
3009 p = kzalloc(driver->num * 2 * sizeof(void *), GFP_KERNEL);
3014 if (!driver->major) {
3015 error = alloc_chrdev_region(&dev, driver->minor_start,
3016 driver->num, driver->name);
3018 driver->major = MAJOR(dev);
3019 driver->minor_start = MINOR(dev);
3022 dev = MKDEV(driver->major, driver->minor_start);
3023 error = register_chrdev_region(dev, driver->num, driver->name);
3031 driver->ttys = (struct tty_struct **)p;
3032 driver->termios = (struct ktermios **)(p + driver->num);
3034 driver->ttys = NULL;
3035 driver->termios = NULL;
3038 cdev_init(&driver->cdev, &tty_fops);
3039 driver->cdev.owner = driver->owner;
3040 error = cdev_add(&driver->cdev, dev, driver->num);
3042 unregister_chrdev_region(dev, driver->num);
3043 driver->ttys = NULL;
3044 driver->termios = NULL;
3049 mutex_lock(&tty_mutex);
3050 list_add(&driver->tty_drivers, &tty_drivers);
3051 mutex_unlock(&tty_mutex);
3053 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3054 for (i = 0; i < driver->num; i++)
3055 tty_register_device(driver, i, NULL);
3057 proc_tty_register_driver(driver);
3058 driver->flags |= TTY_DRIVER_INSTALLED;
3062 EXPORT_SYMBOL(tty_register_driver);
3065 * Called by a tty driver to unregister itself.
3067 int tty_unregister_driver(struct tty_driver *driver)
3071 if (driver->refcount)
3074 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3076 mutex_lock(&tty_mutex);
3077 list_del(&driver->tty_drivers);
3078 mutex_unlock(&tty_mutex);
3082 EXPORT_SYMBOL(tty_unregister_driver);
3084 dev_t tty_devnum(struct tty_struct *tty)
3086 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3088 EXPORT_SYMBOL(tty_devnum);
3090 void proc_clear_tty(struct task_struct *p)
3092 unsigned long flags;
3093 struct tty_struct *tty;
3094 spin_lock_irqsave(&p->sighand->siglock, flags);
3095 tty = p->signal->tty;
3096 p->signal->tty = NULL;
3097 spin_unlock_irqrestore(&p->sighand->siglock, flags);
3101 /* Called under the sighand lock */
3103 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3106 unsigned long flags;
3107 /* We should not have a session or pgrp to put here but.... */
3108 spin_lock_irqsave(&tty->ctrl_lock, flags);
3109 put_pid(tty->session);
3111 tty->pgrp = get_pid(task_pgrp(tsk));
3112 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3113 tty->session = get_pid(task_session(tsk));
3114 if (tsk->signal->tty) {
3115 printk(KERN_DEBUG "tty not NULL!!\n");
3116 tty_kref_put(tsk->signal->tty);
3119 put_pid(tsk->signal->tty_old_pgrp);
3120 tsk->signal->tty = tty_kref_get(tty);
3121 tsk->signal->tty_old_pgrp = NULL;
3124 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3126 spin_lock_irq(&tsk->sighand->siglock);
3127 __proc_set_tty(tsk, tty);
3128 spin_unlock_irq(&tsk->sighand->siglock);
3131 struct tty_struct *get_current_tty(void)
3133 struct tty_struct *tty;
3134 unsigned long flags;
3136 spin_lock_irqsave(¤t->sighand->siglock, flags);
3137 tty = tty_kref_get(current->signal->tty);
3138 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
3141 EXPORT_SYMBOL_GPL(get_current_tty);
3143 void tty_default_fops(struct file_operations *fops)
3149 * Initialize the console device. This is called *early*, so
3150 * we can't necessarily depend on lots of kernel help here.
3151 * Just do some early initializations, and do the complex setup
3154 void __init console_init(void)
3158 /* Setup the default TTY line discipline. */
3162 * set up the console device so that later boot sequences can
3163 * inform about problems etc..
3165 call = __con_initcall_start;
3166 while (call < __con_initcall_end) {
3172 static char *tty_devnode(struct device *dev, mode_t *mode)
3176 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3177 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3182 static int __init tty_class_init(void)
3184 tty_class = class_create(THIS_MODULE, "tty");
3185 if (IS_ERR(tty_class))
3186 return PTR_ERR(tty_class);
3187 tty_class->devnode = tty_devnode;
3191 postcore_initcall(tty_class_init);
3193 /* 3/2004 jmc: why do these devices exist? */
3195 static struct cdev tty_cdev, console_cdev;
3198 * Ok, now we can initialize the rest of the tty devices and can count
3199 * on memory allocations, interrupts etc..
3201 int __init tty_init(void)
3203 cdev_init(&tty_cdev, &tty_fops);
3204 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3205 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3206 panic("Couldn't register /dev/tty driver\n");
3207 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL,
3210 cdev_init(&console_cdev, &console_fops);
3211 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3212 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3213 panic("Couldn't register /dev/console driver\n");
3214 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3218 vty_init(&console_fops);