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/device.h>
94 #include <linux/wait.h>
95 #include <linux/bitops.h>
96 #include <linux/delay.h>
97 #include <linux/seq_file.h>
98 #include <linux/serial.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 /* some functions below drop BTM, so we need this bit */
562 set_bit(TTY_HUPPING, &tty->flags);
564 /* inuse_filps is protected by the single tty lock,
565 this really needs to change if we want to flush the
566 workqueue with the lock held */
567 check_tty_count(tty, "tty_hangup");
569 spin_lock(&tty_files_lock);
570 /* This breaks for file handles being sent over AF_UNIX sockets ? */
571 list_for_each_entry(priv, &tty->tty_files, list) {
573 if (filp->f_op->write == redirected_tty_write)
575 if (filp->f_op->write != tty_write)
578 __tty_fasync(-1, filp, 0); /* can't block */
579 filp->f_op = &hung_up_tty_fops;
581 spin_unlock(&tty_files_lock);
584 * it drops BTM and thus races with reopen
585 * we protect the race by TTY_HUPPING
587 tty_ldisc_hangup(tty);
589 read_lock(&tasklist_lock);
591 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
592 spin_lock_irq(&p->sighand->siglock);
593 if (p->signal->tty == tty) {
594 p->signal->tty = NULL;
595 /* We defer the dereferences outside fo
599 if (!p->signal->leader) {
600 spin_unlock_irq(&p->sighand->siglock);
603 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
604 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
605 put_pid(p->signal->tty_old_pgrp); /* A noop */
606 spin_lock_irqsave(&tty->ctrl_lock, flags);
608 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
609 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
610 spin_unlock_irq(&p->sighand->siglock);
611 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
613 read_unlock(&tasklist_lock);
615 spin_lock_irqsave(&tty->ctrl_lock, flags);
616 clear_bit(TTY_THROTTLED, &tty->flags);
617 clear_bit(TTY_PUSH, &tty->flags);
618 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
619 put_pid(tty->session);
623 tty->ctrl_status = 0;
624 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
626 /* Account for the p->signal references we killed */
631 * If one of the devices matches a console pointer, we
632 * cannot just call hangup() because that will cause
633 * tty->count and state->count to go out of sync.
634 * So we just call close() the right number of times.
638 for (n = 0; n < closecount; n++)
639 tty->ops->close(tty, cons_filp);
640 } else if (tty->ops->hangup)
641 (tty->ops->hangup)(tty);
643 * We don't want to have driver/ldisc interactions beyond
644 * the ones we did here. The driver layer expects no
645 * calls after ->hangup() from the ldisc side. However we
646 * can't yet guarantee all that.
648 set_bit(TTY_HUPPED, &tty->flags);
649 clear_bit(TTY_HUPPING, &tty->flags);
650 tty_ldisc_enable(tty);
658 static void do_tty_hangup(struct work_struct *work)
660 struct tty_struct *tty =
661 container_of(work, struct tty_struct, hangup_work);
667 * tty_hangup - trigger a hangup event
668 * @tty: tty to hangup
670 * A carrier loss (virtual or otherwise) has occurred on this like
671 * schedule a hangup sequence to run after this event.
674 void tty_hangup(struct tty_struct *tty)
676 #ifdef TTY_DEBUG_HANGUP
678 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
680 schedule_work(&tty->hangup_work);
683 EXPORT_SYMBOL(tty_hangup);
686 * tty_vhangup - process vhangup
687 * @tty: tty to hangup
689 * The user has asked via system call for the terminal to be hung up.
690 * We do this synchronously so that when the syscall returns the process
691 * is complete. That guarantee is necessary for security reasons.
694 void tty_vhangup(struct tty_struct *tty)
696 #ifdef TTY_DEBUG_HANGUP
699 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
704 EXPORT_SYMBOL(tty_vhangup);
708 * tty_vhangup_self - process vhangup for own ctty
710 * Perform a vhangup on the current controlling tty
713 void tty_vhangup_self(void)
715 struct tty_struct *tty;
717 tty = get_current_tty();
725 * tty_hung_up_p - was tty hung up
726 * @filp: file pointer of tty
728 * Return true if the tty has been subject to a vhangup or a carrier
732 int tty_hung_up_p(struct file *filp)
734 return (filp->f_op == &hung_up_tty_fops);
737 EXPORT_SYMBOL(tty_hung_up_p);
739 static void session_clear_tty(struct pid *session)
741 struct task_struct *p;
742 do_each_pid_task(session, PIDTYPE_SID, p) {
744 } while_each_pid_task(session, PIDTYPE_SID, p);
748 * disassociate_ctty - disconnect controlling tty
749 * @on_exit: true if exiting so need to "hang up" the session
751 * This function is typically called only by the session leader, when
752 * it wants to disassociate itself from its controlling tty.
754 * It performs the following functions:
755 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
756 * (2) Clears the tty from being controlling the session
757 * (3) Clears the controlling tty for all processes in the
760 * The argument on_exit is set to 1 if called when a process is
761 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
764 * BTM is taken for hysterical raisins, and held when
765 * called from no_tty().
766 * tty_mutex is taken to protect tty
767 * ->siglock is taken to protect ->signal/->sighand
768 * tasklist_lock is taken to walk process list for sessions
769 * ->siglock is taken to protect ->signal/->sighand
772 void disassociate_ctty(int on_exit)
774 struct tty_struct *tty;
775 struct pid *tty_pgrp = NULL;
777 if (!current->signal->leader)
780 tty = get_current_tty();
782 tty_pgrp = get_pid(tty->pgrp);
784 if (tty->driver->type != TTY_DRIVER_TYPE_PTY)
788 } else if (on_exit) {
789 struct pid *old_pgrp;
790 spin_lock_irq(¤t->sighand->siglock);
791 old_pgrp = current->signal->tty_old_pgrp;
792 current->signal->tty_old_pgrp = NULL;
793 spin_unlock_irq(¤t->sighand->siglock);
795 kill_pgrp(old_pgrp, SIGHUP, on_exit);
796 kill_pgrp(old_pgrp, SIGCONT, on_exit);
802 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
804 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
808 spin_lock_irq(¤t->sighand->siglock);
809 put_pid(current->signal->tty_old_pgrp);
810 current->signal->tty_old_pgrp = NULL;
811 spin_unlock_irq(¤t->sighand->siglock);
813 tty = get_current_tty();
816 spin_lock_irqsave(&tty->ctrl_lock, flags);
817 put_pid(tty->session);
821 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
824 #ifdef TTY_DEBUG_HANGUP
825 printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
830 /* Now clear signal->tty under the lock */
831 read_lock(&tasklist_lock);
832 session_clear_tty(task_session(current));
833 read_unlock(&tasklist_lock);
838 * no_tty - Ensure the current process does not have a controlling tty
842 struct task_struct *tsk = current;
844 disassociate_ctty(0);
851 * stop_tty - propagate flow control
854 * Perform flow control to the driver. For PTY/TTY pairs we
855 * must also propagate the TIOCKPKT status. May be called
856 * on an already stopped device and will not re-call the driver
859 * This functionality is used by both the line disciplines for
860 * halting incoming flow and by the driver. It may therefore be
861 * called from any context, may be under the tty atomic_write_lock
865 * Uses the tty control lock internally
868 void stop_tty(struct tty_struct *tty)
871 spin_lock_irqsave(&tty->ctrl_lock, flags);
873 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
877 if (tty->link && tty->link->packet) {
878 tty->ctrl_status &= ~TIOCPKT_START;
879 tty->ctrl_status |= TIOCPKT_STOP;
880 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
882 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
884 (tty->ops->stop)(tty);
887 EXPORT_SYMBOL(stop_tty);
890 * start_tty - propagate flow control
893 * Start a tty that has been stopped if at all possible. Perform
894 * any necessary wakeups and propagate the TIOCPKT status. If this
895 * is the tty was previous stopped and is being started then the
896 * driver start method is invoked and the line discipline woken.
902 void start_tty(struct tty_struct *tty)
905 spin_lock_irqsave(&tty->ctrl_lock, flags);
906 if (!tty->stopped || tty->flow_stopped) {
907 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
911 if (tty->link && tty->link->packet) {
912 tty->ctrl_status &= ~TIOCPKT_STOP;
913 tty->ctrl_status |= TIOCPKT_START;
914 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
916 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
918 (tty->ops->start)(tty);
919 /* If we have a running line discipline it may need kicking */
923 EXPORT_SYMBOL(start_tty);
926 * tty_read - read method for tty device files
927 * @file: pointer to tty file
929 * @count: size of user buffer
932 * Perform the read system call function on this terminal device. Checks
933 * for hung up devices before calling the line discipline method.
936 * Locks the line discipline internally while needed. Multiple
937 * read calls may be outstanding in parallel.
940 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
944 struct inode *inode = file->f_path.dentry->d_inode;
945 struct tty_struct *tty = file_tty(file);
946 struct tty_ldisc *ld;
948 if (tty_paranoia_check(tty, inode, "tty_read"))
950 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
953 /* We want to wait for the line discipline to sort out in this
955 ld = tty_ldisc_ref_wait(tty);
957 i = (ld->ops->read)(tty, file, buf, count);
962 inode->i_atime = current_fs_time(inode->i_sb);
966 void tty_write_unlock(struct tty_struct *tty)
968 mutex_unlock(&tty->atomic_write_lock);
969 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
972 int tty_write_lock(struct tty_struct *tty, int ndelay)
974 if (!mutex_trylock(&tty->atomic_write_lock)) {
977 if (mutex_lock_interruptible(&tty->atomic_write_lock))
984 * Split writes up in sane blocksizes to avoid
985 * denial-of-service type attacks
987 static inline ssize_t do_tty_write(
988 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
989 struct tty_struct *tty,
991 const char __user *buf,
994 ssize_t ret, written = 0;
997 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
1002 * We chunk up writes into a temporary buffer. This
1003 * simplifies low-level drivers immensely, since they
1004 * don't have locking issues and user mode accesses.
1006 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1009 * The default chunk-size is 2kB, because the NTTY
1010 * layer has problems with bigger chunks. It will
1011 * claim to be able to handle more characters than
1014 * FIXME: This can probably go away now except that 64K chunks
1015 * are too likely to fail unless switched to vmalloc...
1018 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1023 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1024 if (tty->write_cnt < chunk) {
1025 unsigned char *buf_chunk;
1030 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1035 kfree(tty->write_buf);
1036 tty->write_cnt = chunk;
1037 tty->write_buf = buf_chunk;
1040 /* Do the write .. */
1042 size_t size = count;
1046 if (copy_from_user(tty->write_buf, buf, size))
1048 ret = write(tty, file, tty->write_buf, size);
1057 if (signal_pending(current))
1062 struct inode *inode = file->f_path.dentry->d_inode;
1063 inode->i_mtime = current_fs_time(inode->i_sb);
1067 tty_write_unlock(tty);
1072 * tty_write_message - write a message to a certain tty, not just the console.
1073 * @tty: the destination tty_struct
1074 * @msg: the message to write
1076 * This is used for messages that need to be redirected to a specific tty.
1077 * We don't put it into the syslog queue right now maybe in the future if
1080 * We must still hold the BTM and test the CLOSING flag for the moment.
1083 void tty_write_message(struct tty_struct *tty, char *msg)
1086 mutex_lock(&tty->atomic_write_lock);
1088 if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) {
1090 tty->ops->write(tty, msg, strlen(msg));
1093 tty_write_unlock(tty);
1100 * tty_write - write method for tty device file
1101 * @file: tty file pointer
1102 * @buf: user data to write
1103 * @count: bytes to write
1106 * Write data to a tty device via the line discipline.
1109 * Locks the line discipline as required
1110 * Writes to the tty driver are serialized by the atomic_write_lock
1111 * and are then processed in chunks to the device. The line discipline
1112 * write method will not be invoked in parallel for each device.
1115 static ssize_t tty_write(struct file *file, const char __user *buf,
1116 size_t count, loff_t *ppos)
1118 struct inode *inode = file->f_path.dentry->d_inode;
1119 struct tty_struct *tty = file_tty(file);
1120 struct tty_ldisc *ld;
1123 if (tty_paranoia_check(tty, inode, "tty_write"))
1125 if (!tty || !tty->ops->write ||
1126 (test_bit(TTY_IO_ERROR, &tty->flags)))
1128 /* Short term debug to catch buggy drivers */
1129 if (tty->ops->write_room == NULL)
1130 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1132 ld = tty_ldisc_ref_wait(tty);
1133 if (!ld->ops->write)
1136 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1137 tty_ldisc_deref(ld);
1141 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1142 size_t count, loff_t *ppos)
1144 struct file *p = NULL;
1146 spin_lock(&redirect_lock);
1151 spin_unlock(&redirect_lock);
1155 res = vfs_write(p, buf, count, &p->f_pos);
1159 return tty_write(file, buf, count, ppos);
1162 static char ptychar[] = "pqrstuvwxyzabcde";
1165 * pty_line_name - generate name for a pty
1166 * @driver: the tty driver in use
1167 * @index: the minor number
1168 * @p: output buffer of at least 6 bytes
1170 * Generate a name from a driver reference and write it to the output
1175 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1177 int i = index + driver->name_base;
1178 /* ->name is initialized to "ttyp", but "tty" is expected */
1179 sprintf(p, "%s%c%x",
1180 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1181 ptychar[i >> 4 & 0xf], i & 0xf);
1185 * tty_line_name - generate name for a tty
1186 * @driver: the tty driver in use
1187 * @index: the minor number
1188 * @p: output buffer of at least 7 bytes
1190 * Generate a name from a driver reference and write it to the output
1195 static void tty_line_name(struct tty_driver *driver, int index, char *p)
1197 sprintf(p, "%s%d", driver->name, index + driver->name_base);
1201 * tty_driver_lookup_tty() - find an existing tty, if any
1202 * @driver: the driver for the tty
1203 * @idx: the minor number
1205 * Return the tty, if found or ERR_PTR() otherwise.
1207 * Locking: tty_mutex must be held. If tty is found, the mutex must
1208 * be held until the 'fast-open' is also done. Will change once we
1209 * have refcounting in the driver and per driver locking
1211 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1212 struct inode *inode, int idx)
1214 struct tty_struct *tty;
1216 if (driver->ops->lookup)
1217 return driver->ops->lookup(driver, inode, idx);
1219 tty = driver->ttys[idx];
1224 * tty_init_termios - helper for termios setup
1225 * @tty: the tty to set up
1227 * Initialise the termios structures for this tty. Thus runs under
1228 * the tty_mutex currently so we can be relaxed about ordering.
1231 int tty_init_termios(struct tty_struct *tty)
1233 struct ktermios *tp;
1234 int idx = tty->index;
1236 tp = tty->driver->termios[idx];
1238 tp = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
1241 memcpy(tp, &tty->driver->init_termios,
1242 sizeof(struct ktermios));
1243 tty->driver->termios[idx] = tp;
1246 tty->termios_locked = tp + 1;
1248 /* Compatibility until drivers always set this */
1249 tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
1250 tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
1253 EXPORT_SYMBOL_GPL(tty_init_termios);
1256 * tty_driver_install_tty() - install a tty entry in the driver
1257 * @driver: the driver for the tty
1260 * Install a tty object into the driver tables. The tty->index field
1261 * will be set by the time this is called. This method is responsible
1262 * for ensuring any need additional structures are allocated and
1265 * Locking: tty_mutex for now
1267 static int tty_driver_install_tty(struct tty_driver *driver,
1268 struct tty_struct *tty)
1270 int idx = tty->index;
1273 if (driver->ops->install) {
1274 ret = driver->ops->install(driver, tty);
1278 if (tty_init_termios(tty) == 0) {
1279 tty_driver_kref_get(driver);
1281 driver->ttys[idx] = tty;
1288 * tty_driver_remove_tty() - remove a tty from the driver tables
1289 * @driver: the driver for the tty
1290 * @idx: the minor number
1292 * Remvoe a tty object from the driver tables. The tty->index field
1293 * will be set by the time this is called.
1295 * Locking: tty_mutex for now
1297 static void tty_driver_remove_tty(struct tty_driver *driver,
1298 struct tty_struct *tty)
1300 if (driver->ops->remove)
1301 driver->ops->remove(driver, tty);
1303 driver->ttys[tty->index] = NULL;
1307 * tty_reopen() - fast re-open of an open tty
1308 * @tty - the tty to open
1310 * Return 0 on success, -errno on error.
1312 * Locking: tty_mutex must be held from the time the tty was found
1313 * till this open completes.
1315 static int tty_reopen(struct tty_struct *tty)
1317 struct tty_driver *driver = tty->driver;
1319 if (test_bit(TTY_CLOSING, &tty->flags) ||
1320 test_bit(TTY_HUPPING, &tty->flags) ||
1321 test_bit(TTY_LDISC_CHANGING, &tty->flags))
1324 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1325 driver->subtype == PTY_TYPE_MASTER) {
1327 * special case for PTY masters: only one open permitted,
1328 * and the slave side open count is incremented as well.
1336 tty->driver = driver; /* N.B. why do this every time?? */
1338 mutex_lock(&tty->ldisc_mutex);
1339 WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
1340 mutex_unlock(&tty->ldisc_mutex);
1346 * tty_init_dev - initialise a tty device
1347 * @driver: tty driver we are opening a device on
1348 * @idx: device index
1349 * @ret_tty: returned tty structure
1350 * @first_ok: ok to open a new device (used by ptmx)
1352 * Prepare a tty device. This may not be a "new" clean device but
1353 * could also be an active device. The pty drivers require special
1354 * handling because of this.
1357 * The function is called under the tty_mutex, which
1358 * protects us from the tty struct or driver itself going away.
1360 * On exit the tty device has the line discipline attached and
1361 * a reference count of 1. If a pair was created for pty/tty use
1362 * and the other was a pty master then it too has a reference count of 1.
1364 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1365 * failed open. The new code protects the open with a mutex, so it's
1366 * really quite straightforward. The mutex locking can probably be
1367 * relaxed for the (most common) case of reopening a tty.
1370 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx,
1373 struct tty_struct *tty;
1376 /* Check if pty master is being opened multiple times */
1377 if (driver->subtype == PTY_TYPE_MASTER &&
1378 (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok) {
1379 return ERR_PTR(-EIO);
1383 * First time open is complex, especially for PTY devices.
1384 * This code guarantees that either everything succeeds and the
1385 * TTY is ready for operation, or else the table slots are vacated
1386 * and the allocated memory released. (Except that the termios
1387 * and locked termios may be retained.)
1390 if (!try_module_get(driver->owner))
1391 return ERR_PTR(-ENODEV);
1393 tty = alloc_tty_struct();
1396 goto err_module_put;
1398 initialize_tty_struct(tty, driver, idx);
1400 retval = tty_driver_install_tty(driver, tty);
1405 * Structures all installed ... call the ldisc open routines.
1406 * If we fail here just call release_tty to clean up. No need
1407 * to decrement the use counts, as release_tty doesn't care.
1409 retval = tty_ldisc_setup(tty, tty->link);
1411 goto err_release_tty;
1415 free_tty_struct(tty);
1417 module_put(driver->owner);
1418 return ERR_PTR(retval);
1420 /* call the tty release_tty routine to clean out this slot */
1422 if (printk_ratelimit())
1423 printk(KERN_INFO "tty_init_dev: ldisc open failed, "
1424 "clearing slot %d\n", idx);
1425 release_tty(tty, idx);
1426 return ERR_PTR(retval);
1429 void tty_free_termios(struct tty_struct *tty)
1431 struct ktermios *tp;
1432 int idx = tty->index;
1433 /* Kill this flag and push into drivers for locking etc */
1434 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
1435 /* FIXME: Locking on ->termios array */
1437 tty->driver->termios[idx] = NULL;
1441 EXPORT_SYMBOL(tty_free_termios);
1443 void tty_shutdown(struct tty_struct *tty)
1445 tty_driver_remove_tty(tty->driver, tty);
1446 tty_free_termios(tty);
1448 EXPORT_SYMBOL(tty_shutdown);
1451 * release_one_tty - release tty structure memory
1452 * @kref: kref of tty we are obliterating
1454 * Releases memory associated with a tty structure, and clears out the
1455 * driver table slots. This function is called when a device is no longer
1456 * in use. It also gets called when setup of a device fails.
1459 * tty_mutex - sometimes only
1460 * takes the file list lock internally when working on the list
1461 * of ttys that the driver keeps.
1463 * This method gets called from a work queue so that the driver private
1464 * cleanup ops can sleep (needed for USB at least)
1466 static void release_one_tty(struct work_struct *work)
1468 struct tty_struct *tty =
1469 container_of(work, struct tty_struct, hangup_work);
1470 struct tty_driver *driver = tty->driver;
1472 if (tty->ops->cleanup)
1473 tty->ops->cleanup(tty);
1476 tty_driver_kref_put(driver);
1477 module_put(driver->owner);
1479 spin_lock(&tty_files_lock);
1480 list_del_init(&tty->tty_files);
1481 spin_unlock(&tty_files_lock);
1484 put_pid(tty->session);
1485 free_tty_struct(tty);
1488 static void queue_release_one_tty(struct kref *kref)
1490 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1492 if (tty->ops->shutdown)
1493 tty->ops->shutdown(tty);
1497 /* The hangup queue is now free so we can reuse it rather than
1498 waste a chunk of memory for each port */
1499 INIT_WORK(&tty->hangup_work, release_one_tty);
1500 schedule_work(&tty->hangup_work);
1504 * tty_kref_put - release a tty kref
1507 * Release a reference to a tty device and if need be let the kref
1508 * layer destruct the object for us
1511 void tty_kref_put(struct tty_struct *tty)
1514 kref_put(&tty->kref, queue_release_one_tty);
1516 EXPORT_SYMBOL(tty_kref_put);
1519 * release_tty - release tty structure memory
1521 * Release both @tty and a possible linked partner (think pty pair),
1522 * and decrement the refcount of the backing module.
1525 * tty_mutex - sometimes only
1526 * takes the file list lock internally when working on the list
1527 * of ttys that the driver keeps.
1528 * FIXME: should we require tty_mutex is held here ??
1531 static void release_tty(struct tty_struct *tty, int idx)
1533 /* This should always be true but check for the moment */
1534 WARN_ON(tty->index != idx);
1537 tty_kref_put(tty->link);
1542 * tty_release - vfs callback for close
1543 * @inode: inode of tty
1544 * @filp: file pointer for handle to tty
1546 * Called the last time each file handle is closed that references
1547 * this tty. There may however be several such references.
1550 * Takes bkl. See tty_release_dev
1552 * Even releasing the tty structures is a tricky business.. We have
1553 * to be very careful that the structures are all released at the
1554 * same time, as interrupts might otherwise get the wrong pointers.
1556 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1557 * lead to double frees or releasing memory still in use.
1560 int tty_release(struct inode *inode, struct file *filp)
1562 struct tty_struct *tty = file_tty(filp);
1563 struct tty_struct *o_tty;
1564 int pty_master, tty_closing, o_tty_closing, do_sleep;
1569 if (tty_paranoia_check(tty, inode, "tty_release_dev"))
1573 check_tty_count(tty, "tty_release_dev");
1575 __tty_fasync(-1, filp, 0);
1578 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1579 tty->driver->subtype == PTY_TYPE_MASTER);
1580 devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
1583 #ifdef TTY_PARANOIA_CHECK
1584 if (idx < 0 || idx >= tty->driver->num) {
1585 printk(KERN_DEBUG "tty_release_dev: bad idx when trying to "
1586 "free (%s)\n", tty->name);
1591 if (tty != tty->driver->ttys[idx]) {
1593 printk(KERN_DEBUG "tty_release_dev: driver.table[%d] not tty "
1594 "for (%s)\n", idx, tty->name);
1597 if (tty->termios != tty->driver->termios[idx]) {
1599 printk(KERN_DEBUG "tty_release_dev: driver.termios[%d] not termios "
1607 #ifdef TTY_DEBUG_HANGUP
1608 printk(KERN_DEBUG "tty_release_dev of %s (tty count=%d)...",
1609 tty_name(tty, buf), tty->count);
1612 #ifdef TTY_PARANOIA_CHECK
1613 if (tty->driver->other &&
1614 !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
1615 if (o_tty != tty->driver->other->ttys[idx]) {
1617 printk(KERN_DEBUG "tty_release_dev: other->table[%d] "
1618 "not o_tty for (%s)\n",
1622 if (o_tty->termios != tty->driver->other->termios[idx]) {
1624 printk(KERN_DEBUG "tty_release_dev: other->termios[%d] "
1625 "not o_termios for (%s)\n",
1629 if (o_tty->link != tty) {
1631 printk(KERN_DEBUG "tty_release_dev: bad pty pointers\n");
1636 if (tty->ops->close)
1637 tty->ops->close(tty, filp);
1641 * Sanity check: if tty->count is going to zero, there shouldn't be
1642 * any waiters on tty->read_wait or tty->write_wait. We test the
1643 * wait queues and kick everyone out _before_ actually starting to
1644 * close. This ensures that we won't block while releasing the tty
1647 * The test for the o_tty closing is necessary, since the master and
1648 * slave sides may close in any order. If the slave side closes out
1649 * first, its count will be one, since the master side holds an open.
1650 * Thus this test wouldn't be triggered at the time the slave closes,
1653 * Note that it's possible for the tty to be opened again while we're
1654 * flushing out waiters. By recalculating the closing flags before
1655 * each iteration we avoid any problems.
1658 /* Guard against races with tty->count changes elsewhere and
1659 opens on /dev/tty */
1661 mutex_lock(&tty_mutex);
1663 tty_closing = tty->count <= 1;
1664 o_tty_closing = o_tty &&
1665 (o_tty->count <= (pty_master ? 1 : 0));
1669 if (waitqueue_active(&tty->read_wait)) {
1670 wake_up_poll(&tty->read_wait, POLLIN);
1673 if (waitqueue_active(&tty->write_wait)) {
1674 wake_up_poll(&tty->write_wait, POLLOUT);
1678 if (o_tty_closing) {
1679 if (waitqueue_active(&o_tty->read_wait)) {
1680 wake_up_poll(&o_tty->read_wait, POLLIN);
1683 if (waitqueue_active(&o_tty->write_wait)) {
1684 wake_up_poll(&o_tty->write_wait, POLLOUT);
1691 printk(KERN_WARNING "tty_release_dev: %s: read/write wait queue "
1692 "active!\n", tty_name(tty, buf));
1694 mutex_unlock(&tty_mutex);
1699 * The closing flags are now consistent with the open counts on
1700 * both sides, and we've completed the last operation that could
1701 * block, so it's safe to proceed with closing.
1704 if (--o_tty->count < 0) {
1705 printk(KERN_WARNING "tty_release_dev: bad pty slave count "
1707 o_tty->count, tty_name(o_tty, buf));
1711 if (--tty->count < 0) {
1712 printk(KERN_WARNING "tty_release_dev: bad tty->count (%d) for %s\n",
1713 tty->count, tty_name(tty, buf));
1718 * We've decremented tty->count, so we need to remove this file
1719 * descriptor off the tty->tty_files list; this serves two
1721 * - check_tty_count sees the correct number of file descriptors
1722 * associated with this tty.
1723 * - do_tty_hangup no longer sees this file descriptor as
1724 * something that needs to be handled for hangups.
1729 * Perform some housekeeping before deciding whether to return.
1731 * Set the TTY_CLOSING flag if this was the last open. In the
1732 * case of a pty we may have to wait around for the other side
1733 * to close, and TTY_CLOSING makes sure we can't be reopened.
1736 set_bit(TTY_CLOSING, &tty->flags);
1738 set_bit(TTY_CLOSING, &o_tty->flags);
1741 * If _either_ side is closing, make sure there aren't any
1742 * processes that still think tty or o_tty is their controlling
1745 if (tty_closing || o_tty_closing) {
1746 read_lock(&tasklist_lock);
1747 session_clear_tty(tty->session);
1749 session_clear_tty(o_tty->session);
1750 read_unlock(&tasklist_lock);
1753 mutex_unlock(&tty_mutex);
1755 /* check whether both sides are closing ... */
1756 if (!tty_closing || (o_tty && !o_tty_closing)) {
1761 #ifdef TTY_DEBUG_HANGUP
1762 printk(KERN_DEBUG "freeing tty structure...");
1765 * Ask the line discipline code to release its structures
1767 tty_ldisc_release(tty, o_tty);
1769 * The release_tty function takes care of the details of clearing
1770 * the slots and preserving the termios structure.
1772 release_tty(tty, idx);
1774 /* Make this pty number available for reallocation */
1776 devpts_kill_index(inode, idx);
1782 * tty_open - open a tty device
1783 * @inode: inode of device file
1784 * @filp: file pointer to tty
1786 * tty_open and tty_release keep up the tty count that contains the
1787 * number of opens done on a tty. We cannot use the inode-count, as
1788 * different inodes might point to the same tty.
1790 * Open-counting is needed for pty masters, as well as for keeping
1791 * track of serial lines: DTR is dropped when the last close happens.
1792 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1794 * The termios state of a pty is reset on first open so that
1795 * settings don't persist across reuse.
1797 * Locking: tty_mutex protects tty, get_tty_driver and tty_init_dev work.
1798 * tty->count should protect the rest.
1799 * ->siglock protects ->signal/->sighand
1802 static int tty_open(struct inode *inode, struct file *filp)
1804 struct tty_struct *tty = NULL;
1806 struct tty_driver *driver;
1808 dev_t device = inode->i_rdev;
1809 unsigned saved_flags = filp->f_flags;
1811 nonseekable_open(inode, filp);
1814 noctty = filp->f_flags & O_NOCTTY;
1818 mutex_lock(&tty_mutex);
1821 if (device == MKDEV(TTYAUX_MAJOR, 0)) {
1822 tty = get_current_tty();
1825 mutex_unlock(&tty_mutex);
1828 driver = tty_driver_kref_get(tty->driver);
1830 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1832 /* FIXME: Should we take a driver reference ? */
1837 if (device == MKDEV(TTY_MAJOR, 0)) {
1838 extern struct tty_driver *console_driver;
1839 driver = tty_driver_kref_get(console_driver);
1845 if (device == MKDEV(TTYAUX_MAJOR, 1)) {
1846 struct tty_driver *console_driver = console_device(&index);
1847 if (console_driver) {
1848 driver = tty_driver_kref_get(console_driver);
1850 /* Don't let /dev/console block */
1851 filp->f_flags |= O_NONBLOCK;
1857 mutex_unlock(&tty_mutex);
1861 driver = get_tty_driver(device, &index);
1864 mutex_unlock(&tty_mutex);
1869 /* check whether we're reopening an existing tty */
1870 tty = tty_driver_lookup_tty(driver, inode, index);
1874 mutex_unlock(&tty_mutex);
1875 return PTR_ERR(tty);
1880 retval = tty_reopen(tty);
1882 tty = ERR_PTR(retval);
1884 tty = tty_init_dev(driver, index, 0);
1886 mutex_unlock(&tty_mutex);
1887 tty_driver_kref_put(driver);
1890 return PTR_ERR(tty);
1893 retval = tty_add_file(tty, filp);
1899 check_tty_count(tty, "tty_open");
1900 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1901 tty->driver->subtype == PTY_TYPE_MASTER)
1903 #ifdef TTY_DEBUG_HANGUP
1904 printk(KERN_DEBUG "opening %s...", tty->name);
1907 retval = tty->ops->open(tty, filp);
1910 filp->f_flags = saved_flags;
1912 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
1913 !capable(CAP_SYS_ADMIN))
1917 #ifdef TTY_DEBUG_HANGUP
1918 printk(KERN_DEBUG "error %d in opening %s...", retval,
1921 tty_unlock(); /* need to call tty_release without BTM */
1922 tty_release(inode, filp);
1923 if (retval != -ERESTARTSYS)
1926 if (signal_pending(current))
1931 * Need to reset f_op in case a hangup happened.
1934 if (filp->f_op == &hung_up_tty_fops)
1935 filp->f_op = &tty_fops;
1942 mutex_lock(&tty_mutex);
1944 spin_lock_irq(¤t->sighand->siglock);
1946 current->signal->leader &&
1947 !current->signal->tty &&
1948 tty->session == NULL)
1949 __proc_set_tty(current, tty);
1950 spin_unlock_irq(¤t->sighand->siglock);
1952 mutex_unlock(&tty_mutex);
1959 * tty_poll - check tty status
1960 * @filp: file being polled
1961 * @wait: poll wait structures to update
1963 * Call the line discipline polling method to obtain the poll
1964 * status of the device.
1966 * Locking: locks called line discipline but ldisc poll method
1967 * may be re-entered freely by other callers.
1970 static unsigned int tty_poll(struct file *filp, poll_table *wait)
1972 struct tty_struct *tty = file_tty(filp);
1973 struct tty_ldisc *ld;
1976 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll"))
1979 ld = tty_ldisc_ref_wait(tty);
1981 ret = (ld->ops->poll)(tty, filp, wait);
1982 tty_ldisc_deref(ld);
1986 static int __tty_fasync(int fd, struct file *filp, int on)
1988 struct tty_struct *tty = file_tty(filp);
1989 unsigned long flags;
1992 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
1995 retval = fasync_helper(fd, filp, on, &tty->fasync);
2002 if (!waitqueue_active(&tty->read_wait))
2003 tty->minimum_to_wake = 1;
2004 spin_lock_irqsave(&tty->ctrl_lock, flags);
2007 type = PIDTYPE_PGID;
2009 pid = task_pid(current);
2013 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2014 retval = __f_setown(filp, pid, type, 0);
2019 if (!tty->fasync && !waitqueue_active(&tty->read_wait))
2020 tty->minimum_to_wake = N_TTY_BUF_SIZE;
2027 static int tty_fasync(int fd, struct file *filp, int on)
2031 retval = __tty_fasync(fd, filp, on);
2037 * tiocsti - fake input character
2038 * @tty: tty to fake input into
2039 * @p: pointer to character
2041 * Fake input to a tty device. Does the necessary locking and
2044 * FIXME: does not honour flow control ??
2047 * Called functions take tty_ldisc_lock
2048 * current->signal->tty check is safe without locks
2050 * FIXME: may race normal receive processing
2053 static int tiocsti(struct tty_struct *tty, char __user *p)
2056 struct tty_ldisc *ld;
2058 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2060 if (get_user(ch, p))
2062 tty_audit_tiocsti(tty, ch);
2063 ld = tty_ldisc_ref_wait(tty);
2064 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2065 tty_ldisc_deref(ld);
2070 * tiocgwinsz - implement window query ioctl
2072 * @arg: user buffer for result
2074 * Copies the kernel idea of the window size into the user buffer.
2076 * Locking: tty->termios_mutex is taken to ensure the winsize data
2080 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2084 mutex_lock(&tty->termios_mutex);
2085 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2086 mutex_unlock(&tty->termios_mutex);
2088 return err ? -EFAULT: 0;
2092 * tty_do_resize - resize event
2093 * @tty: tty being resized
2094 * @rows: rows (character)
2095 * @cols: cols (character)
2097 * Update the termios variables and send the necessary signals to
2098 * peform a terminal resize correctly
2101 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2104 unsigned long flags;
2107 mutex_lock(&tty->termios_mutex);
2108 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2110 /* Get the PID values and reference them so we can
2111 avoid holding the tty ctrl lock while sending signals */
2112 spin_lock_irqsave(&tty->ctrl_lock, flags);
2113 pgrp = get_pid(tty->pgrp);
2114 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2117 kill_pgrp(pgrp, SIGWINCH, 1);
2122 mutex_unlock(&tty->termios_mutex);
2127 * tiocswinsz - implement window size set ioctl
2128 * @tty; tty side of tty
2129 * @arg: user buffer for result
2131 * Copies the user idea of the window size to the kernel. Traditionally
2132 * this is just advisory information but for the Linux console it
2133 * actually has driver level meaning and triggers a VC resize.
2136 * Driver dependent. The default do_resize method takes the
2137 * tty termios mutex and ctrl_lock. The console takes its own lock
2138 * then calls into the default method.
2141 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2143 struct winsize tmp_ws;
2144 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2147 if (tty->ops->resize)
2148 return tty->ops->resize(tty, &tmp_ws);
2150 return tty_do_resize(tty, &tmp_ws);
2154 * tioccons - allow admin to move logical console
2155 * @file: the file to become console
2157 * Allow the administrator to move the redirected console device
2159 * Locking: uses redirect_lock to guard the redirect information
2162 static int tioccons(struct file *file)
2164 if (!capable(CAP_SYS_ADMIN))
2166 if (file->f_op->write == redirected_tty_write) {
2168 spin_lock(&redirect_lock);
2171 spin_unlock(&redirect_lock);
2176 spin_lock(&redirect_lock);
2178 spin_unlock(&redirect_lock);
2183 spin_unlock(&redirect_lock);
2188 * fionbio - non blocking ioctl
2189 * @file: file to set blocking value
2190 * @p: user parameter
2192 * Historical tty interfaces had a blocking control ioctl before
2193 * the generic functionality existed. This piece of history is preserved
2194 * in the expected tty API of posix OS's.
2196 * Locking: none, the open file handle ensures it won't go away.
2199 static int fionbio(struct file *file, int __user *p)
2203 if (get_user(nonblock, p))
2206 spin_lock(&file->f_lock);
2208 file->f_flags |= O_NONBLOCK;
2210 file->f_flags &= ~O_NONBLOCK;
2211 spin_unlock(&file->f_lock);
2216 * tiocsctty - set controlling tty
2217 * @tty: tty structure
2218 * @arg: user argument
2220 * This ioctl is used to manage job control. It permits a session
2221 * leader to set this tty as the controlling tty for the session.
2224 * Takes tty_mutex() to protect tty instance
2225 * Takes tasklist_lock internally to walk sessions
2226 * Takes ->siglock() when updating signal->tty
2229 static int tiocsctty(struct tty_struct *tty, int arg)
2232 if (current->signal->leader && (task_session(current) == tty->session))
2235 mutex_lock(&tty_mutex);
2237 * The process must be a session leader and
2238 * not have a controlling tty already.
2240 if (!current->signal->leader || current->signal->tty) {
2247 * This tty is already the controlling
2248 * tty for another session group!
2250 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2254 read_lock(&tasklist_lock);
2255 session_clear_tty(tty->session);
2256 read_unlock(&tasklist_lock);
2262 proc_set_tty(current, tty);
2264 mutex_unlock(&tty_mutex);
2269 * tty_get_pgrp - return a ref counted pgrp pid
2272 * Returns a refcounted instance of the pid struct for the process
2273 * group controlling the tty.
2276 struct pid *tty_get_pgrp(struct tty_struct *tty)
2278 unsigned long flags;
2281 spin_lock_irqsave(&tty->ctrl_lock, flags);
2282 pgrp = get_pid(tty->pgrp);
2283 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2287 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2290 * tiocgpgrp - get process group
2291 * @tty: tty passed by user
2292 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2295 * Obtain the process group of the tty. If there is no process group
2298 * Locking: none. Reference to current->signal->tty is safe.
2301 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2306 * (tty == real_tty) is a cheap way of
2307 * testing if the tty is NOT a master pty.
2309 if (tty == real_tty && current->signal->tty != real_tty)
2311 pid = tty_get_pgrp(real_tty);
2312 ret = put_user(pid_vnr(pid), p);
2318 * tiocspgrp - attempt to set process group
2319 * @tty: tty passed by user
2320 * @real_tty: tty side device matching tty passed by user
2323 * Set the process group of the tty to the session passed. Only
2324 * permitted where the tty session is our session.
2326 * Locking: RCU, ctrl lock
2329 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2333 int retval = tty_check_change(real_tty);
2334 unsigned long flags;
2340 if (!current->signal->tty ||
2341 (current->signal->tty != real_tty) ||
2342 (real_tty->session != task_session(current)))
2344 if (get_user(pgrp_nr, p))
2349 pgrp = find_vpid(pgrp_nr);
2354 if (session_of_pgrp(pgrp) != task_session(current))
2357 spin_lock_irqsave(&tty->ctrl_lock, flags);
2358 put_pid(real_tty->pgrp);
2359 real_tty->pgrp = get_pid(pgrp);
2360 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2367 * tiocgsid - get session id
2368 * @tty: tty passed by user
2369 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2370 * @p: pointer to returned session id
2372 * Obtain the session id of the tty. If there is no session
2375 * Locking: none. Reference to current->signal->tty is safe.
2378 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2381 * (tty == real_tty) is a cheap way of
2382 * testing if the tty is NOT a master pty.
2384 if (tty == real_tty && current->signal->tty != real_tty)
2386 if (!real_tty->session)
2388 return put_user(pid_vnr(real_tty->session), p);
2392 * tiocsetd - set line discipline
2394 * @p: pointer to user data
2396 * Set the line discipline according to user request.
2398 * Locking: see tty_set_ldisc, this function is just a helper
2401 static int tiocsetd(struct tty_struct *tty, int __user *p)
2406 if (get_user(ldisc, p))
2409 ret = tty_set_ldisc(tty, ldisc);
2415 * send_break - performed time break
2416 * @tty: device to break on
2417 * @duration: timeout in mS
2419 * Perform a timed break on hardware that lacks its own driver level
2420 * timed break functionality.
2423 * atomic_write_lock serializes
2427 static int send_break(struct tty_struct *tty, unsigned int duration)
2431 if (tty->ops->break_ctl == NULL)
2434 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2435 retval = tty->ops->break_ctl(tty, duration);
2437 /* Do the work ourselves */
2438 if (tty_write_lock(tty, 0) < 0)
2440 retval = tty->ops->break_ctl(tty, -1);
2443 if (!signal_pending(current))
2444 msleep_interruptible(duration);
2445 retval = tty->ops->break_ctl(tty, 0);
2447 tty_write_unlock(tty);
2448 if (signal_pending(current))
2455 * tty_tiocmget - get modem status
2457 * @file: user file pointer
2458 * @p: pointer to result
2460 * Obtain the modem status bits from the tty driver if the feature
2461 * is supported. Return -EINVAL if it is not available.
2463 * Locking: none (up to the driver)
2466 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2468 int retval = -EINVAL;
2470 if (tty->ops->tiocmget) {
2471 retval = tty->ops->tiocmget(tty);
2474 retval = put_user(retval, p);
2480 * tty_tiocmset - set modem status
2482 * @cmd: command - clear bits, set bits or set all
2483 * @p: pointer to desired bits
2485 * Set the modem status bits from the tty driver if the feature
2486 * is supported. Return -EINVAL if it is not available.
2488 * Locking: none (up to the driver)
2491 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2495 unsigned int set, clear, val;
2497 if (tty->ops->tiocmset == NULL)
2500 retval = get_user(val, p);
2516 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2517 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2518 return tty->ops->tiocmset(tty, set, clear);
2521 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2523 int retval = -EINVAL;
2524 struct serial_icounter_struct icount;
2525 memset(&icount, 0, sizeof(icount));
2526 if (tty->ops->get_icount)
2527 retval = tty->ops->get_icount(tty, &icount);
2530 if (copy_to_user(arg, &icount, sizeof(icount)))
2535 struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2537 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2538 tty->driver->subtype == PTY_TYPE_MASTER)
2542 EXPORT_SYMBOL(tty_pair_get_tty);
2544 struct tty_struct *tty_pair_get_pty(struct tty_struct *tty)
2546 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2547 tty->driver->subtype == PTY_TYPE_MASTER)
2551 EXPORT_SYMBOL(tty_pair_get_pty);
2554 * Split this up, as gcc can choke on it otherwise..
2556 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2558 struct tty_struct *tty = file_tty(file);
2559 struct tty_struct *real_tty;
2560 void __user *p = (void __user *)arg;
2562 struct tty_ldisc *ld;
2563 struct inode *inode = file->f_dentry->d_inode;
2565 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2568 real_tty = tty_pair_get_tty(tty);
2571 * Factor out some common prep work
2579 retval = tty_check_change(tty);
2582 if (cmd != TIOCCBRK) {
2583 tty_wait_until_sent(tty, 0);
2584 if (signal_pending(current))
2595 return tiocsti(tty, p);
2597 return tiocgwinsz(real_tty, p);
2599 return tiocswinsz(real_tty, p);
2601 return real_tty != tty ? -EINVAL : tioccons(file);
2603 return fionbio(file, p);
2605 set_bit(TTY_EXCLUSIVE, &tty->flags);
2608 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2611 if (current->signal->tty != tty)
2616 return tiocsctty(tty, arg);
2618 return tiocgpgrp(tty, real_tty, p);
2620 return tiocspgrp(tty, real_tty, p);
2622 return tiocgsid(tty, real_tty, p);
2624 return put_user(tty->ldisc->ops->num, (int __user *)p);
2626 return tiocsetd(tty, p);
2628 if (!capable(CAP_SYS_ADMIN))
2634 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2635 return put_user(ret, (unsigned int __user *)p);
2640 case TIOCSBRK: /* Turn break on, unconditionally */
2641 if (tty->ops->break_ctl)
2642 return tty->ops->break_ctl(tty, -1);
2644 case TIOCCBRK: /* Turn break off, unconditionally */
2645 if (tty->ops->break_ctl)
2646 return tty->ops->break_ctl(tty, 0);
2648 case TCSBRK: /* SVID version: non-zero arg --> no break */
2649 /* non-zero arg means wait for all output data
2650 * to be sent (performed above) but don't send break.
2651 * This is used by the tcdrain() termios function.
2654 return send_break(tty, 250);
2656 case TCSBRKP: /* support for POSIX tcsendbreak() */
2657 return send_break(tty, arg ? arg*100 : 250);
2660 return tty_tiocmget(tty, p);
2664 return tty_tiocmset(tty, cmd, p);
2666 retval = tty_tiocgicount(tty, p);
2667 /* For the moment allow fall through to the old method */
2668 if (retval != -EINVAL)
2675 /* flush tty buffer and allow ldisc to process ioctl */
2676 tty_buffer_flush(tty);
2681 if (tty->ops->ioctl) {
2682 retval = (tty->ops->ioctl)(tty, cmd, arg);
2683 if (retval != -ENOIOCTLCMD)
2686 ld = tty_ldisc_ref_wait(tty);
2688 if (ld->ops->ioctl) {
2689 retval = ld->ops->ioctl(tty, file, cmd, arg);
2690 if (retval == -ENOIOCTLCMD)
2693 tty_ldisc_deref(ld);
2697 #ifdef CONFIG_COMPAT
2698 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2701 struct inode *inode = file->f_dentry->d_inode;
2702 struct tty_struct *tty = file_tty(file);
2703 struct tty_ldisc *ld;
2704 int retval = -ENOIOCTLCMD;
2706 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2709 if (tty->ops->compat_ioctl) {
2710 retval = (tty->ops->compat_ioctl)(tty, cmd, arg);
2711 if (retval != -ENOIOCTLCMD)
2715 ld = tty_ldisc_ref_wait(tty);
2716 if (ld->ops->compat_ioctl)
2717 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2718 tty_ldisc_deref(ld);
2725 * This implements the "Secure Attention Key" --- the idea is to
2726 * prevent trojan horses by killing all processes associated with this
2727 * tty when the user hits the "Secure Attention Key". Required for
2728 * super-paranoid applications --- see the Orange Book for more details.
2730 * This code could be nicer; ideally it should send a HUP, wait a few
2731 * seconds, then send a INT, and then a KILL signal. But you then
2732 * have to coordinate with the init process, since all processes associated
2733 * with the current tty must be dead before the new getty is allowed
2736 * Now, if it would be correct ;-/ The current code has a nasty hole -
2737 * it doesn't catch files in flight. We may send the descriptor to ourselves
2738 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2740 * Nasty bug: do_SAK is being called in interrupt context. This can
2741 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2743 void __do_SAK(struct tty_struct *tty)
2748 struct task_struct *g, *p;
2749 struct pid *session;
2752 struct fdtable *fdt;
2756 session = tty->session;
2758 tty_ldisc_flush(tty);
2760 tty_driver_flush_buffer(tty);
2762 read_lock(&tasklist_lock);
2763 /* Kill the entire session */
2764 do_each_pid_task(session, PIDTYPE_SID, p) {
2765 printk(KERN_NOTICE "SAK: killed process %d"
2766 " (%s): task_session(p)==tty->session\n",
2767 task_pid_nr(p), p->comm);
2768 send_sig(SIGKILL, p, 1);
2769 } while_each_pid_task(session, PIDTYPE_SID, p);
2770 /* Now kill any processes that happen to have the
2773 do_each_thread(g, p) {
2774 if (p->signal->tty == tty) {
2775 printk(KERN_NOTICE "SAK: killed process %d"
2776 " (%s): task_session(p)==tty->session\n",
2777 task_pid_nr(p), p->comm);
2778 send_sig(SIGKILL, p, 1);
2784 * We don't take a ref to the file, so we must
2785 * hold ->file_lock instead.
2787 spin_lock(&p->files->file_lock);
2788 fdt = files_fdtable(p->files);
2789 for (i = 0; i < fdt->max_fds; i++) {
2790 filp = fcheck_files(p->files, i);
2793 if (filp->f_op->read == tty_read &&
2794 file_tty(filp) == tty) {
2795 printk(KERN_NOTICE "SAK: killed process %d"
2796 " (%s): fd#%d opened to the tty\n",
2797 task_pid_nr(p), p->comm, i);
2798 force_sig(SIGKILL, p);
2802 spin_unlock(&p->files->file_lock);
2805 } while_each_thread(g, p);
2806 read_unlock(&tasklist_lock);
2810 static void do_SAK_work(struct work_struct *work)
2812 struct tty_struct *tty =
2813 container_of(work, struct tty_struct, SAK_work);
2818 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2819 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2820 * the values which we write to it will be identical to the values which it
2821 * already has. --akpm
2823 void do_SAK(struct tty_struct *tty)
2827 schedule_work(&tty->SAK_work);
2830 EXPORT_SYMBOL(do_SAK);
2832 static int dev_match_devt(struct device *dev, void *data)
2835 return dev->devt == *devt;
2838 /* Must put_device() after it's unused! */
2839 static struct device *tty_get_device(struct tty_struct *tty)
2841 dev_t devt = tty_devnum(tty);
2842 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
2847 * initialize_tty_struct
2848 * @tty: tty to initialize
2850 * This subroutine initializes a tty structure that has been newly
2853 * Locking: none - tty in question must not be exposed at this point
2856 void initialize_tty_struct(struct tty_struct *tty,
2857 struct tty_driver *driver, int idx)
2859 memset(tty, 0, sizeof(struct tty_struct));
2860 kref_init(&tty->kref);
2861 tty->magic = TTY_MAGIC;
2862 tty_ldisc_init(tty);
2863 tty->session = NULL;
2865 tty->overrun_time = jiffies;
2866 tty->buf.head = tty->buf.tail = NULL;
2867 tty_buffer_init(tty);
2868 mutex_init(&tty->termios_mutex);
2869 mutex_init(&tty->ldisc_mutex);
2870 init_waitqueue_head(&tty->write_wait);
2871 init_waitqueue_head(&tty->read_wait);
2872 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2873 mutex_init(&tty->atomic_read_lock);
2874 mutex_init(&tty->atomic_write_lock);
2875 mutex_init(&tty->output_lock);
2876 mutex_init(&tty->echo_lock);
2877 spin_lock_init(&tty->read_lock);
2878 spin_lock_init(&tty->ctrl_lock);
2879 INIT_LIST_HEAD(&tty->tty_files);
2880 INIT_WORK(&tty->SAK_work, do_SAK_work);
2882 tty->driver = driver;
2883 tty->ops = driver->ops;
2885 tty_line_name(driver, idx, tty->name);
2886 tty->dev = tty_get_device(tty);
2890 * deinitialize_tty_struct
2891 * @tty: tty to deinitialize
2893 * This subroutine deinitializes a tty structure that has been newly
2894 * allocated but tty_release cannot be called on that yet.
2896 * Locking: none - tty in question must not be exposed at this point
2898 void deinitialize_tty_struct(struct tty_struct *tty)
2900 tty_ldisc_deinit(tty);
2904 * tty_put_char - write one character to a tty
2908 * Write one byte to the tty using the provided put_char method
2909 * if present. Returns the number of characters successfully output.
2911 * Note: the specific put_char operation in the driver layer may go
2912 * away soon. Don't call it directly, use this method
2915 int tty_put_char(struct tty_struct *tty, unsigned char ch)
2917 if (tty->ops->put_char)
2918 return tty->ops->put_char(tty, ch);
2919 return tty->ops->write(tty, &ch, 1);
2921 EXPORT_SYMBOL_GPL(tty_put_char);
2923 struct class *tty_class;
2926 * tty_register_device - register a tty device
2927 * @driver: the tty driver that describes the tty device
2928 * @index: the index in the tty driver for this tty device
2929 * @device: a struct device that is associated with this tty device.
2930 * This field is optional, if there is no known struct device
2931 * for this tty device it can be set to NULL safely.
2933 * Returns a pointer to the struct device for this tty device
2934 * (or ERR_PTR(-EFOO) on error).
2936 * This call is required to be made to register an individual tty device
2937 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2938 * that bit is not set, this function should not be called by a tty
2944 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
2945 struct device *device)
2948 dev_t dev = MKDEV(driver->major, driver->minor_start) + index;
2950 if (index >= driver->num) {
2951 printk(KERN_ERR "Attempt to register invalid tty line number "
2953 return ERR_PTR(-EINVAL);
2956 if (driver->type == TTY_DRIVER_TYPE_PTY)
2957 pty_line_name(driver, index, name);
2959 tty_line_name(driver, index, name);
2961 return device_create(tty_class, device, dev, NULL, name);
2963 EXPORT_SYMBOL(tty_register_device);
2966 * tty_unregister_device - unregister a tty device
2967 * @driver: the tty driver that describes the tty device
2968 * @index: the index in the tty driver for this tty device
2970 * If a tty device is registered with a call to tty_register_device() then
2971 * this function must be called when the tty device is gone.
2976 void tty_unregister_device(struct tty_driver *driver, unsigned index)
2978 device_destroy(tty_class,
2979 MKDEV(driver->major, driver->minor_start) + index);
2981 EXPORT_SYMBOL(tty_unregister_device);
2983 struct tty_driver *alloc_tty_driver(int lines)
2985 struct tty_driver *driver;
2987 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
2989 kref_init(&driver->kref);
2990 driver->magic = TTY_DRIVER_MAGIC;
2991 driver->num = lines;
2992 /* later we'll move allocation of tables here */
2996 EXPORT_SYMBOL(alloc_tty_driver);
2998 static void destruct_tty_driver(struct kref *kref)
3000 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3002 struct ktermios *tp;
3005 if (driver->flags & TTY_DRIVER_INSTALLED) {
3007 * Free the termios and termios_locked structures because
3008 * we don't want to get memory leaks when modular tty
3009 * drivers are removed from the kernel.
3011 for (i = 0; i < driver->num; i++) {
3012 tp = driver->termios[i];
3014 driver->termios[i] = NULL;
3017 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3018 tty_unregister_device(driver, i);
3021 proc_tty_unregister_driver(driver);
3022 driver->ttys = NULL;
3023 driver->termios = NULL;
3025 cdev_del(&driver->cdev);
3030 void tty_driver_kref_put(struct tty_driver *driver)
3032 kref_put(&driver->kref, destruct_tty_driver);
3034 EXPORT_SYMBOL(tty_driver_kref_put);
3036 void tty_set_operations(struct tty_driver *driver,
3037 const struct tty_operations *op)
3041 EXPORT_SYMBOL(tty_set_operations);
3043 void put_tty_driver(struct tty_driver *d)
3045 tty_driver_kref_put(d);
3047 EXPORT_SYMBOL(put_tty_driver);
3050 * Called by a tty driver to register itself.
3052 int tty_register_driver(struct tty_driver *driver)
3060 if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) {
3061 p = kzalloc(driver->num * 2 * sizeof(void *), GFP_KERNEL);
3066 if (!driver->major) {
3067 error = alloc_chrdev_region(&dev, driver->minor_start,
3068 driver->num, driver->name);
3070 driver->major = MAJOR(dev);
3071 driver->minor_start = MINOR(dev);
3074 dev = MKDEV(driver->major, driver->minor_start);
3075 error = register_chrdev_region(dev, driver->num, driver->name);
3083 driver->ttys = (struct tty_struct **)p;
3084 driver->termios = (struct ktermios **)(p + driver->num);
3086 driver->ttys = NULL;
3087 driver->termios = NULL;
3090 cdev_init(&driver->cdev, &tty_fops);
3091 driver->cdev.owner = driver->owner;
3092 error = cdev_add(&driver->cdev, dev, driver->num);
3094 unregister_chrdev_region(dev, driver->num);
3095 driver->ttys = NULL;
3096 driver->termios = NULL;
3101 mutex_lock(&tty_mutex);
3102 list_add(&driver->tty_drivers, &tty_drivers);
3103 mutex_unlock(&tty_mutex);
3105 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3106 for (i = 0; i < driver->num; i++) {
3107 d = tty_register_device(driver, i, NULL);
3114 proc_tty_register_driver(driver);
3115 driver->flags |= TTY_DRIVER_INSTALLED;
3119 for (i--; i >= 0; i--)
3120 tty_unregister_device(driver, i);
3122 mutex_lock(&tty_mutex);
3123 list_del(&driver->tty_drivers);
3124 mutex_unlock(&tty_mutex);
3126 unregister_chrdev_region(dev, driver->num);
3127 driver->ttys = NULL;
3128 driver->termios = NULL;
3133 EXPORT_SYMBOL(tty_register_driver);
3136 * Called by a tty driver to unregister itself.
3138 int tty_unregister_driver(struct tty_driver *driver)
3142 if (driver->refcount)
3145 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3147 mutex_lock(&tty_mutex);
3148 list_del(&driver->tty_drivers);
3149 mutex_unlock(&tty_mutex);
3153 EXPORT_SYMBOL(tty_unregister_driver);
3155 dev_t tty_devnum(struct tty_struct *tty)
3157 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3159 EXPORT_SYMBOL(tty_devnum);
3161 void proc_clear_tty(struct task_struct *p)
3163 unsigned long flags;
3164 struct tty_struct *tty;
3165 spin_lock_irqsave(&p->sighand->siglock, flags);
3166 tty = p->signal->tty;
3167 p->signal->tty = NULL;
3168 spin_unlock_irqrestore(&p->sighand->siglock, flags);
3172 /* Called under the sighand lock */
3174 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3177 unsigned long flags;
3178 /* We should not have a session or pgrp to put here but.... */
3179 spin_lock_irqsave(&tty->ctrl_lock, flags);
3180 put_pid(tty->session);
3182 tty->pgrp = get_pid(task_pgrp(tsk));
3183 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3184 tty->session = get_pid(task_session(tsk));
3185 if (tsk->signal->tty) {
3186 printk(KERN_DEBUG "tty not NULL!!\n");
3187 tty_kref_put(tsk->signal->tty);
3190 put_pid(tsk->signal->tty_old_pgrp);
3191 tsk->signal->tty = tty_kref_get(tty);
3192 tsk->signal->tty_old_pgrp = NULL;
3195 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3197 spin_lock_irq(&tsk->sighand->siglock);
3198 __proc_set_tty(tsk, tty);
3199 spin_unlock_irq(&tsk->sighand->siglock);
3202 struct tty_struct *get_current_tty(void)
3204 struct tty_struct *tty;
3205 unsigned long flags;
3207 spin_lock_irqsave(¤t->sighand->siglock, flags);
3208 tty = tty_kref_get(current->signal->tty);
3209 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
3212 EXPORT_SYMBOL_GPL(get_current_tty);
3214 void tty_default_fops(struct file_operations *fops)
3220 * Initialize the console device. This is called *early*, so
3221 * we can't necessarily depend on lots of kernel help here.
3222 * Just do some early initializations, and do the complex setup
3225 void __init console_init(void)
3229 /* Setup the default TTY line discipline. */
3233 * set up the console device so that later boot sequences can
3234 * inform about problems etc..
3236 call = __con_initcall_start;
3237 while (call < __con_initcall_end) {
3243 static char *tty_devnode(struct device *dev, mode_t *mode)
3247 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3248 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3253 static int __init tty_class_init(void)
3255 tty_class = class_create(THIS_MODULE, "tty");
3256 if (IS_ERR(tty_class))
3257 return PTR_ERR(tty_class);
3258 tty_class->devnode = tty_devnode;
3262 postcore_initcall(tty_class_init);
3264 /* 3/2004 jmc: why do these devices exist? */
3265 static struct cdev tty_cdev, console_cdev;
3267 static ssize_t show_cons_active(struct device *dev,
3268 struct device_attribute *attr, char *buf)
3270 struct console *cs[16];
3276 for_each_console(c) {
3281 if ((c->flags & CON_ENABLED) == 0)
3284 if (i >= ARRAY_SIZE(cs))
3288 count += sprintf(buf + count, "%s%d%c",
3289 cs[i]->name, cs[i]->index, i ? ' ':'\n');
3294 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3296 static struct device *consdev;
3298 void console_sysfs_notify(void)
3301 sysfs_notify(&consdev->kobj, NULL, "active");
3305 * Ok, now we can initialize the rest of the tty devices and can count
3306 * on memory allocations, interrupts etc..
3308 int __init tty_init(void)
3310 cdev_init(&tty_cdev, &tty_fops);
3311 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3312 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3313 panic("Couldn't register /dev/tty driver\n");
3314 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3316 cdev_init(&console_cdev, &console_fops);
3317 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3318 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3319 panic("Couldn't register /dev/console driver\n");
3320 consdev = device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3322 if (IS_ERR(consdev))
3325 WARN_ON(device_create_file(consdev, &dev_attr_active) < 0);
3328 vty_init(&console_fops);