2 * Copyright (C) 1991, 1992 Linus Torvalds
6 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
7 * or rs-channels. It also implements echoing, cooked mode etc.
9 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
11 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
12 * tty_struct and tty_queue structures. Previously there was an array
13 * of 256 tty_struct's which was statically allocated, and the
14 * tty_queue structures were allocated at boot time. Both are now
15 * dynamically allocated only when the tty is open.
17 * Also restructured routines so that there is more of a separation
18 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
19 * the low-level tty routines (serial.c, pty.c, console.c). This
20 * makes for cleaner and more compact code. -TYT, 9/17/92
22 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
23 * which can be dynamically activated and de-activated by the line
24 * discipline handling modules (like SLIP).
26 * NOTE: pay no attention to the line discipline code (yet); its
27 * interface is still subject to change in this version...
30 * Added functionality to the OPOST tty handling. No delays, but all
31 * other bits should be there.
32 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
34 * Rewrote canonical mode and added more termios flags.
35 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
37 * Reorganized FASYNC support so mouse code can share it.
38 * -- ctm@ardi.com, 9Sep95
40 * New TIOCLINUX variants added.
41 * -- mj@k332.feld.cvut.cz, 19-Nov-95
43 * Restrict vt switching via ioctl()
44 * -- grif@cs.ucr.edu, 5-Dec-95
46 * Move console and virtual terminal code to more appropriate files,
47 * implement CONFIG_VT and generalize console device interface.
48 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
50 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
51 * -- Bill Hawes <whawes@star.net>, June 97
53 * Added devfs support.
54 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
56 * Added support for a Unix98-style ptmx device.
57 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
59 * Reduced memory usage for older ARM systems
60 * -- Russell King <rmk@arm.linux.org.uk>
62 * Move do_SAK() into process context. Less stack use in devfs functions.
63 * alloc_tty_struct() always uses kmalloc()
64 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
67 #include <linux/types.h>
68 #include <linux/major.h>
69 #include <linux/errno.h>
70 #include <linux/signal.h>
71 #include <linux/fcntl.h>
72 #include <linux/sched.h>
73 #include <linux/interrupt.h>
74 #include <linux/tty.h>
75 #include <linux/tty_driver.h>
76 #include <linux/tty_flip.h>
77 #include <linux/devpts_fs.h>
78 #include <linux/file.h>
79 #include <linux/fdtable.h>
80 #include <linux/console.h>
81 #include <linux/timer.h>
82 #include <linux/ctype.h>
85 #include <linux/string.h>
86 #include <linux/slab.h>
87 #include <linux/poll.h>
88 #include <linux/proc_fs.h>
89 #include <linux/init.h>
90 #include <linux/module.h>
91 #include <linux/device.h>
92 #include <linux/wait.h>
93 #include <linux/bitops.h>
94 #include <linux/delay.h>
95 #include <linux/seq_file.h>
96 #include <linux/serial.h>
97 #include <linux/ratelimit.h>
99 #include <linux/uaccess.h>
101 #include <linux/kbd_kern.h>
102 #include <linux/vt_kern.h>
103 #include <linux/selection.h>
105 #include <linux/kmod.h>
106 #include <linux/nsproxy.h>
108 #undef TTY_DEBUG_HANGUP
109 #ifdef TTY_DEBUG_HANGUP
110 # define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args)
112 # define tty_debug_hangup(tty, f, args...) do { } while (0)
115 #define TTY_PARANOIA_CHECK 1
116 #define CHECK_TTY_COUNT 1
118 struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
119 .c_iflag = ICRNL | IXON,
120 .c_oflag = OPOST | ONLCR,
121 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
122 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
123 ECHOCTL | ECHOKE | IEXTEN,
129 EXPORT_SYMBOL(tty_std_termios);
131 /* This list gets poked at by procfs and various bits of boot up code. This
132 could do with some rationalisation such as pulling the tty proc function
135 LIST_HEAD(tty_drivers); /* linked list of tty drivers */
137 /* Mutex to protect creating and releasing a tty. This is shared with
138 vt.c for deeply disgusting hack reasons */
139 DEFINE_MUTEX(tty_mutex);
140 EXPORT_SYMBOL(tty_mutex);
142 /* Spinlock to protect the tty->tty_files list */
143 DEFINE_SPINLOCK(tty_files_lock);
145 static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
146 static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
147 ssize_t redirected_tty_write(struct file *, const char __user *,
149 static unsigned int tty_poll(struct file *, poll_table *);
150 static int tty_open(struct inode *, struct file *);
151 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
153 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
156 #define tty_compat_ioctl NULL
158 static int __tty_fasync(int fd, struct file *filp, int on);
159 static int tty_fasync(int fd, struct file *filp, int on);
160 static void release_tty(struct tty_struct *tty, int idx);
163 * free_tty_struct - free a disused tty
164 * @tty: tty struct to free
166 * Free the write buffers, tty queue and tty memory itself.
168 * Locking: none. Must be called after tty is definitely unused
171 static void free_tty_struct(struct tty_struct *tty)
173 tty_ldisc_deinit(tty);
174 put_device(tty->dev);
175 kfree(tty->write_buf);
176 tty->magic = 0xDEADDEAD;
180 static inline struct tty_struct *file_tty(struct file *file)
182 return ((struct tty_file_private *)file->private_data)->tty;
185 int tty_alloc_file(struct file *file)
187 struct tty_file_private *priv;
189 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
193 file->private_data = priv;
198 /* Associate a new file with the tty structure */
199 void tty_add_file(struct tty_struct *tty, struct file *file)
201 struct tty_file_private *priv = file->private_data;
206 spin_lock(&tty_files_lock);
207 list_add(&priv->list, &tty->tty_files);
208 spin_unlock(&tty_files_lock);
212 * tty_free_file - free file->private_data
214 * This shall be used only for fail path handling when tty_add_file was not
217 void tty_free_file(struct file *file)
219 struct tty_file_private *priv = file->private_data;
221 file->private_data = NULL;
225 /* Delete file from its tty */
226 static void tty_del_file(struct file *file)
228 struct tty_file_private *priv = file->private_data;
230 spin_lock(&tty_files_lock);
231 list_del(&priv->list);
232 spin_unlock(&tty_files_lock);
237 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
240 * tty_name - return tty naming
241 * @tty: tty structure
243 * Convert a tty structure into a name. The name reflects the kernel
244 * naming policy and if udev is in use may not reflect user space
249 const char *tty_name(const struct tty_struct *tty)
251 if (!tty) /* Hmm. NULL pointer. That's fun. */
256 EXPORT_SYMBOL(tty_name);
258 const char *tty_driver_name(const struct tty_struct *tty)
260 if (!tty || !tty->driver)
262 return tty->driver->name;
265 static int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
268 #ifdef TTY_PARANOIA_CHECK
270 pr_warn("(%d:%d): %s: NULL tty\n",
271 imajor(inode), iminor(inode), routine);
274 if (tty->magic != TTY_MAGIC) {
275 pr_warn("(%d:%d): %s: bad magic number\n",
276 imajor(inode), iminor(inode), routine);
283 /* Caller must hold tty_lock */
284 static int check_tty_count(struct tty_struct *tty, const char *routine)
286 #ifdef CHECK_TTY_COUNT
290 spin_lock(&tty_files_lock);
291 list_for_each(p, &tty->tty_files) {
294 spin_unlock(&tty_files_lock);
295 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
296 tty->driver->subtype == PTY_TYPE_SLAVE &&
297 tty->link && tty->link->count)
299 if (tty->count != count) {
300 tty_warn(tty, "%s: tty->count(%d) != #fd's(%d)\n",
301 routine, tty->count, count);
309 * get_tty_driver - find device of a tty
310 * @dev_t: device identifier
311 * @index: returns the index of the tty
313 * This routine returns a tty driver structure, given a device number
314 * and also passes back the index number.
316 * Locking: caller must hold tty_mutex
319 static struct tty_driver *get_tty_driver(dev_t device, int *index)
321 struct tty_driver *p;
323 list_for_each_entry(p, &tty_drivers, tty_drivers) {
324 dev_t base = MKDEV(p->major, p->minor_start);
325 if (device < base || device >= base + p->num)
327 *index = device - base;
328 return tty_driver_kref_get(p);
333 #ifdef CONFIG_CONSOLE_POLL
336 * tty_find_polling_driver - find device of a polled tty
337 * @name: name string to match
338 * @line: pointer to resulting tty line nr
340 * This routine returns a tty driver structure, given a name
341 * and the condition that the tty driver is capable of polled
344 struct tty_driver *tty_find_polling_driver(char *name, int *line)
346 struct tty_driver *p, *res = NULL;
351 for (str = name; *str; str++)
352 if ((*str >= '0' && *str <= '9') || *str == ',')
358 tty_line = simple_strtoul(str, &str, 10);
360 mutex_lock(&tty_mutex);
361 /* Search through the tty devices to look for a match */
362 list_for_each_entry(p, &tty_drivers, tty_drivers) {
363 if (strncmp(name, p->name, len) != 0)
371 if (tty_line >= 0 && tty_line < p->num && p->ops &&
372 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
373 res = tty_driver_kref_get(p);
378 mutex_unlock(&tty_mutex);
382 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
386 * tty_check_change - check for POSIX terminal changes
389 * If we try to write to, or set the state of, a terminal and we're
390 * not in the foreground, send a SIGTTOU. If the signal is blocked or
391 * ignored, go ahead and perform the operation. (POSIX 7.2)
396 int __tty_check_change(struct tty_struct *tty, int sig)
399 struct pid *pgrp, *tty_pgrp;
402 if (current->signal->tty != tty)
406 pgrp = task_pgrp(current);
408 spin_lock_irqsave(&tty->ctrl_lock, flags);
409 tty_pgrp = tty->pgrp;
410 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
412 if (tty_pgrp && pgrp != tty->pgrp) {
413 if (is_ignored(sig)) {
416 } else if (is_current_pgrp_orphaned())
419 kill_pgrp(pgrp, sig, 1);
420 set_thread_flag(TIF_SIGPENDING);
427 tty_warn(tty, "sig=%d, tty->pgrp == NULL!\n", sig);
432 int tty_check_change(struct tty_struct *tty)
434 return __tty_check_change(tty, SIGTTOU);
436 EXPORT_SYMBOL(tty_check_change);
438 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
439 size_t count, loff_t *ppos)
444 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
445 size_t count, loff_t *ppos)
450 /* No kernel lock held - none needed ;) */
451 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
453 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
456 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
459 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
462 static long hung_up_tty_compat_ioctl(struct file *file,
463 unsigned int cmd, unsigned long arg)
465 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
468 static const struct file_operations tty_fops = {
473 .unlocked_ioctl = tty_ioctl,
474 .compat_ioctl = tty_compat_ioctl,
476 .release = tty_release,
477 .fasync = tty_fasync,
480 static const struct file_operations console_fops = {
483 .write = redirected_tty_write,
485 .unlocked_ioctl = tty_ioctl,
486 .compat_ioctl = tty_compat_ioctl,
488 .release = tty_release,
489 .fasync = tty_fasync,
492 static const struct file_operations hung_up_tty_fops = {
494 .read = hung_up_tty_read,
495 .write = hung_up_tty_write,
496 .poll = hung_up_tty_poll,
497 .unlocked_ioctl = hung_up_tty_ioctl,
498 .compat_ioctl = hung_up_tty_compat_ioctl,
499 .release = tty_release,
502 static DEFINE_SPINLOCK(redirect_lock);
503 static struct file *redirect;
506 void proc_clear_tty(struct task_struct *p)
509 struct tty_struct *tty;
510 spin_lock_irqsave(&p->sighand->siglock, flags);
511 tty = p->signal->tty;
512 p->signal->tty = NULL;
513 spin_unlock_irqrestore(&p->sighand->siglock, flags);
518 * proc_set_tty - set the controlling terminal
520 * Only callable by the session leader and only if it does not already have
521 * a controlling terminal.
523 * Caller must hold: tty_lock()
524 * a readlock on tasklist_lock
527 static void __proc_set_tty(struct tty_struct *tty)
531 spin_lock_irqsave(&tty->ctrl_lock, flags);
533 * The session and fg pgrp references will be non-NULL if
534 * tiocsctty() is stealing the controlling tty
536 put_pid(tty->session);
538 tty->pgrp = get_pid(task_pgrp(current));
539 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
540 tty->session = get_pid(task_session(current));
541 if (current->signal->tty) {
542 tty_debug(tty, "current tty %s not NULL!!\n",
543 current->signal->tty->name);
544 tty_kref_put(current->signal->tty);
546 put_pid(current->signal->tty_old_pgrp);
547 current->signal->tty = tty_kref_get(tty);
548 current->signal->tty_old_pgrp = NULL;
551 static void proc_set_tty(struct tty_struct *tty)
553 spin_lock_irq(¤t->sighand->siglock);
555 spin_unlock_irq(¤t->sighand->siglock);
558 struct tty_struct *get_current_tty(void)
560 struct tty_struct *tty;
563 spin_lock_irqsave(¤t->sighand->siglock, flags);
564 tty = tty_kref_get(current->signal->tty);
565 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
568 EXPORT_SYMBOL_GPL(get_current_tty);
570 static void session_clear_tty(struct pid *session)
572 struct task_struct *p;
573 do_each_pid_task(session, PIDTYPE_SID, p) {
575 } while_each_pid_task(session, PIDTYPE_SID, p);
579 * tty_wakeup - request more data
582 * Internal and external helper for wakeups of tty. This function
583 * informs the line discipline if present that the driver is ready
584 * to receive more output data.
587 void tty_wakeup(struct tty_struct *tty)
589 struct tty_ldisc *ld;
591 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
592 ld = tty_ldisc_ref(tty);
594 if (ld->ops->write_wakeup)
595 ld->ops->write_wakeup(tty);
599 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
602 EXPORT_SYMBOL_GPL(tty_wakeup);
605 * tty_signal_session_leader - sends SIGHUP to session leader
606 * @tty controlling tty
607 * @exit_session if non-zero, signal all foreground group processes
609 * Send SIGHUP and SIGCONT to the session leader and its process group.
610 * Optionally, signal all processes in the foreground process group.
612 * Returns the number of processes in the session with this tty
613 * as their controlling terminal. This value is used to drop
614 * tty references for those processes.
616 static int tty_signal_session_leader(struct tty_struct *tty, int exit_session)
618 struct task_struct *p;
620 struct pid *tty_pgrp = NULL;
622 read_lock(&tasklist_lock);
624 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
625 spin_lock_irq(&p->sighand->siglock);
626 if (p->signal->tty == tty) {
627 p->signal->tty = NULL;
628 /* We defer the dereferences outside fo
632 if (!p->signal->leader) {
633 spin_unlock_irq(&p->sighand->siglock);
636 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
637 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
638 put_pid(p->signal->tty_old_pgrp); /* A noop */
639 spin_lock(&tty->ctrl_lock);
640 tty_pgrp = get_pid(tty->pgrp);
642 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
643 spin_unlock(&tty->ctrl_lock);
644 spin_unlock_irq(&p->sighand->siglock);
645 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
647 read_unlock(&tasklist_lock);
651 kill_pgrp(tty_pgrp, SIGHUP, exit_session);
659 * __tty_hangup - actual handler for hangup events
662 * This can be called by a "kworker" kernel thread. That is process
663 * synchronous but doesn't hold any locks, so we need to make sure we
664 * have the appropriate locks for what we're doing.
666 * The hangup event clears any pending redirections onto the hung up
667 * device. It ensures future writes will error and it does the needed
668 * line discipline hangup and signal delivery. The tty object itself
673 * redirect lock for undoing redirection
674 * file list lock for manipulating list of ttys
675 * tty_ldiscs_lock from called functions
676 * termios_rwsem resetting termios data
677 * tasklist_lock to walk task list for hangup event
678 * ->siglock to protect ->signal/->sighand
680 static void __tty_hangup(struct tty_struct *tty, int exit_session)
682 struct file *cons_filp = NULL;
683 struct file *filp, *f = NULL;
684 struct tty_file_private *priv;
685 int closecount = 0, n;
692 spin_lock(&redirect_lock);
693 if (redirect && file_tty(redirect) == tty) {
697 spin_unlock(&redirect_lock);
701 if (test_bit(TTY_HUPPED, &tty->flags)) {
706 /* inuse_filps is protected by the single tty lock,
707 this really needs to change if we want to flush the
708 workqueue with the lock held */
709 check_tty_count(tty, "tty_hangup");
711 spin_lock(&tty_files_lock);
712 /* This breaks for file handles being sent over AF_UNIX sockets ? */
713 list_for_each_entry(priv, &tty->tty_files, list) {
715 if (filp->f_op->write == redirected_tty_write)
717 if (filp->f_op->write != tty_write)
720 __tty_fasync(-1, filp, 0); /* can't block */
721 filp->f_op = &hung_up_tty_fops;
723 spin_unlock(&tty_files_lock);
725 refs = tty_signal_session_leader(tty, exit_session);
726 /* Account for the p->signal references we killed */
730 tty_ldisc_hangup(tty);
732 spin_lock_irq(&tty->ctrl_lock);
733 clear_bit(TTY_THROTTLED, &tty->flags);
734 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
735 put_pid(tty->session);
739 tty->ctrl_status = 0;
740 spin_unlock_irq(&tty->ctrl_lock);
743 * If one of the devices matches a console pointer, we
744 * cannot just call hangup() because that will cause
745 * tty->count and state->count to go out of sync.
746 * So we just call close() the right number of times.
750 for (n = 0; n < closecount; n++)
751 tty->ops->close(tty, cons_filp);
752 } else if (tty->ops->hangup)
753 tty->ops->hangup(tty);
755 * We don't want to have driver/ldisc interactions beyond
756 * the ones we did here. The driver layer expects no
757 * calls after ->hangup() from the ldisc side. However we
758 * can't yet guarantee all that.
760 set_bit(TTY_HUPPED, &tty->flags);
767 static void do_tty_hangup(struct work_struct *work)
769 struct tty_struct *tty =
770 container_of(work, struct tty_struct, hangup_work);
772 __tty_hangup(tty, 0);
776 * tty_hangup - trigger a hangup event
777 * @tty: tty to hangup
779 * A carrier loss (virtual or otherwise) has occurred on this like
780 * schedule a hangup sequence to run after this event.
783 void tty_hangup(struct tty_struct *tty)
785 tty_debug_hangup(tty, "hangup\n");
786 schedule_work(&tty->hangup_work);
789 EXPORT_SYMBOL(tty_hangup);
792 * tty_vhangup - process vhangup
793 * @tty: tty to hangup
795 * The user has asked via system call for the terminal to be hung up.
796 * We do this synchronously so that when the syscall returns the process
797 * is complete. That guarantee is necessary for security reasons.
800 void tty_vhangup(struct tty_struct *tty)
802 tty_debug_hangup(tty, "vhangup\n");
803 __tty_hangup(tty, 0);
806 EXPORT_SYMBOL(tty_vhangup);
810 * tty_vhangup_self - process vhangup for own ctty
812 * Perform a vhangup on the current controlling tty
815 void tty_vhangup_self(void)
817 struct tty_struct *tty;
819 tty = get_current_tty();
827 * tty_vhangup_session - hangup session leader exit
828 * @tty: tty to hangup
830 * The session leader is exiting and hanging up its controlling terminal.
831 * Every process in the foreground process group is signalled SIGHUP.
833 * We do this synchronously so that when the syscall returns the process
834 * is complete. That guarantee is necessary for security reasons.
837 static void tty_vhangup_session(struct tty_struct *tty)
839 tty_debug_hangup(tty, "session hangup\n");
840 __tty_hangup(tty, 1);
844 * tty_hung_up_p - was tty hung up
845 * @filp: file pointer of tty
847 * Return true if the tty has been subject to a vhangup or a carrier
851 int tty_hung_up_p(struct file *filp)
853 return (filp->f_op == &hung_up_tty_fops);
856 EXPORT_SYMBOL(tty_hung_up_p);
859 * disassociate_ctty - disconnect controlling tty
860 * @on_exit: true if exiting so need to "hang up" the session
862 * This function is typically called only by the session leader, when
863 * it wants to disassociate itself from its controlling tty.
865 * It performs the following functions:
866 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
867 * (2) Clears the tty from being controlling the session
868 * (3) Clears the controlling tty for all processes in the
871 * The argument on_exit is set to 1 if called when a process is
872 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
875 * BTM is taken for hysterical raisins, and held when
876 * called from no_tty().
877 * tty_mutex is taken to protect tty
878 * ->siglock is taken to protect ->signal/->sighand
879 * tasklist_lock is taken to walk process list for sessions
880 * ->siglock is taken to protect ->signal/->sighand
883 void disassociate_ctty(int on_exit)
885 struct tty_struct *tty;
887 if (!current->signal->leader)
890 tty = get_current_tty();
892 if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) {
893 tty_vhangup_session(tty);
895 struct pid *tty_pgrp = tty_get_pgrp(tty);
897 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
899 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
905 } else if (on_exit) {
906 struct pid *old_pgrp;
907 spin_lock_irq(¤t->sighand->siglock);
908 old_pgrp = current->signal->tty_old_pgrp;
909 current->signal->tty_old_pgrp = NULL;
910 spin_unlock_irq(¤t->sighand->siglock);
912 kill_pgrp(old_pgrp, SIGHUP, on_exit);
913 kill_pgrp(old_pgrp, SIGCONT, on_exit);
919 spin_lock_irq(¤t->sighand->siglock);
920 put_pid(current->signal->tty_old_pgrp);
921 current->signal->tty_old_pgrp = NULL;
923 tty = tty_kref_get(current->signal->tty);
926 spin_lock_irqsave(&tty->ctrl_lock, flags);
927 put_pid(tty->session);
931 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
934 tty_debug_hangup(tty, "no current tty\n");
936 spin_unlock_irq(¤t->sighand->siglock);
937 /* Now clear signal->tty under the lock */
938 read_lock(&tasklist_lock);
939 session_clear_tty(task_session(current));
940 read_unlock(&tasklist_lock);
945 * no_tty - Ensure the current process does not have a controlling tty
949 /* FIXME: Review locking here. The tty_lock never covered any race
950 between a new association and proc_clear_tty but possible we need
951 to protect against this anyway */
952 struct task_struct *tsk = current;
953 disassociate_ctty(0);
959 * stop_tty - propagate flow control
962 * Perform flow control to the driver. May be called
963 * on an already stopped device and will not re-call the driver
966 * This functionality is used by both the line disciplines for
967 * halting incoming flow and by the driver. It may therefore be
968 * called from any context, may be under the tty atomic_write_lock
975 void __stop_tty(struct tty_struct *tty)
984 void stop_tty(struct tty_struct *tty)
988 spin_lock_irqsave(&tty->flow_lock, flags);
990 spin_unlock_irqrestore(&tty->flow_lock, flags);
992 EXPORT_SYMBOL(stop_tty);
995 * start_tty - propagate flow control
998 * Start a tty that has been stopped if at all possible. If this
999 * tty was previous stopped and is now being started, the driver
1000 * start method is invoked and the line discipline woken.
1006 void __start_tty(struct tty_struct *tty)
1008 if (!tty->stopped || tty->flow_stopped)
1011 if (tty->ops->start)
1012 tty->ops->start(tty);
1016 void start_tty(struct tty_struct *tty)
1018 unsigned long flags;
1020 spin_lock_irqsave(&tty->flow_lock, flags);
1022 spin_unlock_irqrestore(&tty->flow_lock, flags);
1024 EXPORT_SYMBOL(start_tty);
1026 static void tty_update_time(struct timespec *time)
1028 unsigned long sec = get_seconds();
1031 * We only care if the two values differ in anything other than the
1032 * lower three bits (i.e every 8 seconds). If so, then we can update
1033 * the time of the tty device, otherwise it could be construded as a
1034 * security leak to let userspace know the exact timing of the tty.
1036 if ((sec ^ time->tv_sec) & ~7)
1041 * tty_read - read method for tty device files
1042 * @file: pointer to tty file
1044 * @count: size of user buffer
1047 * Perform the read system call function on this terminal device. Checks
1048 * for hung up devices before calling the line discipline method.
1051 * Locks the line discipline internally while needed. Multiple
1052 * read calls may be outstanding in parallel.
1055 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
1059 struct inode *inode = file_inode(file);
1060 struct tty_struct *tty = file_tty(file);
1061 struct tty_ldisc *ld;
1063 if (tty_paranoia_check(tty, inode, "tty_read"))
1065 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
1068 /* We want to wait for the line discipline to sort out in this
1070 ld = tty_ldisc_ref_wait(tty);
1072 return hung_up_tty_read(file, buf, count, ppos);
1074 i = ld->ops->read(tty, file, buf, count);
1077 tty_ldisc_deref(ld);
1080 tty_update_time(&inode->i_atime);
1085 static void tty_write_unlock(struct tty_struct *tty)
1087 mutex_unlock(&tty->atomic_write_lock);
1088 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
1091 static int tty_write_lock(struct tty_struct *tty, int ndelay)
1093 if (!mutex_trylock(&tty->atomic_write_lock)) {
1096 if (mutex_lock_interruptible(&tty->atomic_write_lock))
1097 return -ERESTARTSYS;
1103 * Split writes up in sane blocksizes to avoid
1104 * denial-of-service type attacks
1106 static inline ssize_t do_tty_write(
1107 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
1108 struct tty_struct *tty,
1110 const char __user *buf,
1113 ssize_t ret, written = 0;
1116 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
1121 * We chunk up writes into a temporary buffer. This
1122 * simplifies low-level drivers immensely, since they
1123 * don't have locking issues and user mode accesses.
1125 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1128 * The default chunk-size is 2kB, because the NTTY
1129 * layer has problems with bigger chunks. It will
1130 * claim to be able to handle more characters than
1133 * FIXME: This can probably go away now except that 64K chunks
1134 * are too likely to fail unless switched to vmalloc...
1137 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1142 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1143 if (tty->write_cnt < chunk) {
1144 unsigned char *buf_chunk;
1149 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1154 kfree(tty->write_buf);
1155 tty->write_cnt = chunk;
1156 tty->write_buf = buf_chunk;
1159 /* Do the write .. */
1161 size_t size = count;
1165 if (copy_from_user(tty->write_buf, buf, size))
1167 ret = write(tty, file, tty->write_buf, size);
1176 if (signal_pending(current))
1181 tty_update_time(&file_inode(file)->i_mtime);
1185 tty_write_unlock(tty);
1190 * tty_write_message - write a message to a certain tty, not just the console.
1191 * @tty: the destination tty_struct
1192 * @msg: the message to write
1194 * This is used for messages that need to be redirected to a specific tty.
1195 * We don't put it into the syslog queue right now maybe in the future if
1198 * We must still hold the BTM and test the CLOSING flag for the moment.
1201 void tty_write_message(struct tty_struct *tty, char *msg)
1204 mutex_lock(&tty->atomic_write_lock);
1206 if (tty->ops->write && tty->count > 0)
1207 tty->ops->write(tty, msg, strlen(msg));
1209 tty_write_unlock(tty);
1216 * tty_write - write method for tty device file
1217 * @file: tty file pointer
1218 * @buf: user data to write
1219 * @count: bytes to write
1222 * Write data to a tty device via the line discipline.
1225 * Locks the line discipline as required
1226 * Writes to the tty driver are serialized by the atomic_write_lock
1227 * and are then processed in chunks to the device. The line discipline
1228 * write method will not be invoked in parallel for each device.
1231 static ssize_t tty_write(struct file *file, const char __user *buf,
1232 size_t count, loff_t *ppos)
1234 struct tty_struct *tty = file_tty(file);
1235 struct tty_ldisc *ld;
1238 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1240 if (!tty || !tty->ops->write ||
1241 (test_bit(TTY_IO_ERROR, &tty->flags)))
1243 /* Short term debug to catch buggy drivers */
1244 if (tty->ops->write_room == NULL)
1245 tty_err(tty, "missing write_room method\n");
1246 ld = tty_ldisc_ref_wait(tty);
1248 return hung_up_tty_write(file, buf, count, ppos);
1249 if (!ld->ops->write)
1252 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1253 tty_ldisc_deref(ld);
1257 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1258 size_t count, loff_t *ppos)
1260 struct file *p = NULL;
1262 spin_lock(&redirect_lock);
1264 p = get_file(redirect);
1265 spin_unlock(&redirect_lock);
1269 res = vfs_write(p, buf, count, &p->f_pos);
1273 return tty_write(file, buf, count, ppos);
1277 * tty_send_xchar - send priority character
1279 * Send a high priority character to the tty even if stopped
1281 * Locking: none for xchar method, write ordering for write method.
1284 int tty_send_xchar(struct tty_struct *tty, char ch)
1286 int was_stopped = tty->stopped;
1288 if (tty->ops->send_xchar) {
1289 down_read(&tty->termios_rwsem);
1290 tty->ops->send_xchar(tty, ch);
1291 up_read(&tty->termios_rwsem);
1295 if (tty_write_lock(tty, 0) < 0)
1296 return -ERESTARTSYS;
1298 down_read(&tty->termios_rwsem);
1301 tty->ops->write(tty, &ch, 1);
1304 up_read(&tty->termios_rwsem);
1305 tty_write_unlock(tty);
1309 static char ptychar[] = "pqrstuvwxyzabcde";
1312 * pty_line_name - generate name for a pty
1313 * @driver: the tty driver in use
1314 * @index: the minor number
1315 * @p: output buffer of at least 6 bytes
1317 * Generate a name from a driver reference and write it to the output
1322 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1324 int i = index + driver->name_base;
1325 /* ->name is initialized to "ttyp", but "tty" is expected */
1326 sprintf(p, "%s%c%x",
1327 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1328 ptychar[i >> 4 & 0xf], i & 0xf);
1332 * tty_line_name - generate name for a tty
1333 * @driver: the tty driver in use
1334 * @index: the minor number
1335 * @p: output buffer of at least 7 bytes
1337 * Generate a name from a driver reference and write it to the output
1342 static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1344 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1345 return sprintf(p, "%s", driver->name);
1347 return sprintf(p, "%s%d", driver->name,
1348 index + driver->name_base);
1352 * tty_driver_lookup_tty() - find an existing tty, if any
1353 * @driver: the driver for the tty
1354 * @idx: the minor number
1356 * Return the tty, if found. If not found, return NULL or ERR_PTR() if the
1357 * driver lookup() method returns an error.
1359 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1361 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1362 struct inode *inode, int idx)
1364 struct tty_struct *tty;
1366 if (driver->ops->lookup)
1367 tty = driver->ops->lookup(driver, inode, idx);
1369 tty = driver->ttys[idx];
1377 * tty_init_termios - helper for termios setup
1378 * @tty: the tty to set up
1380 * Initialise the termios structures for this tty. Thus runs under
1381 * the tty_mutex currently so we can be relaxed about ordering.
1384 void tty_init_termios(struct tty_struct *tty)
1386 struct ktermios *tp;
1387 int idx = tty->index;
1389 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1390 tty->termios = tty->driver->init_termios;
1392 /* Check for lazy saved data */
1393 tp = tty->driver->termios[idx];
1396 tty->termios.c_line = tty->driver->init_termios.c_line;
1398 tty->termios = tty->driver->init_termios;
1400 /* Compatibility until drivers always set this */
1401 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1402 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1404 EXPORT_SYMBOL_GPL(tty_init_termios);
1406 int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1408 tty_init_termios(tty);
1409 tty_driver_kref_get(driver);
1411 driver->ttys[tty->index] = tty;
1414 EXPORT_SYMBOL_GPL(tty_standard_install);
1417 * tty_driver_install_tty() - install a tty entry in the driver
1418 * @driver: the driver for the tty
1421 * Install a tty object into the driver tables. The tty->index field
1422 * will be set by the time this is called. This method is responsible
1423 * for ensuring any need additional structures are allocated and
1426 * Locking: tty_mutex for now
1428 static int tty_driver_install_tty(struct tty_driver *driver,
1429 struct tty_struct *tty)
1431 return driver->ops->install ? driver->ops->install(driver, tty) :
1432 tty_standard_install(driver, tty);
1436 * tty_driver_remove_tty() - remove a tty from the driver tables
1437 * @driver: the driver for the tty
1438 * @idx: the minor number
1440 * Remvoe a tty object from the driver tables. The tty->index field
1441 * will be set by the time this is called.
1443 * Locking: tty_mutex for now
1445 static void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1447 if (driver->ops->remove)
1448 driver->ops->remove(driver, tty);
1450 driver->ttys[tty->index] = NULL;
1454 * tty_reopen() - fast re-open of an open tty
1455 * @tty - the tty to open
1457 * Return 0 on success, -errno on error.
1458 * Re-opens on master ptys are not allowed and return -EIO.
1460 * Locking: Caller must hold tty_lock
1462 static int tty_reopen(struct tty_struct *tty)
1464 struct tty_driver *driver = tty->driver;
1466 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1467 driver->subtype == PTY_TYPE_MASTER)
1473 if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
1478 WARN_ON(!tty->ldisc);
1484 * tty_init_dev - initialise a tty device
1485 * @driver: tty driver we are opening a device on
1486 * @idx: device index
1487 * @ret_tty: returned tty structure
1489 * Prepare a tty device. This may not be a "new" clean device but
1490 * could also be an active device. The pty drivers require special
1491 * handling because of this.
1494 * The function is called under the tty_mutex, which
1495 * protects us from the tty struct or driver itself going away.
1497 * On exit the tty device has the line discipline attached and
1498 * a reference count of 1. If a pair was created for pty/tty use
1499 * and the other was a pty master then it too has a reference count of 1.
1501 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1502 * failed open. The new code protects the open with a mutex, so it's
1503 * really quite straightforward. The mutex locking can probably be
1504 * relaxed for the (most common) case of reopening a tty.
1507 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1509 struct tty_struct *tty;
1513 * First time open is complex, especially for PTY devices.
1514 * This code guarantees that either everything succeeds and the
1515 * TTY is ready for operation, or else the table slots are vacated
1516 * and the allocated memory released. (Except that the termios
1517 * and locked termios may be retained.)
1520 if (!try_module_get(driver->owner))
1521 return ERR_PTR(-ENODEV);
1523 tty = alloc_tty_struct(driver, idx);
1526 goto err_module_put;
1530 retval = tty_driver_install_tty(driver, tty);
1535 tty->port = driver->ports[idx];
1537 WARN_RATELIMIT(!tty->port,
1538 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1539 __func__, tty->driver->name);
1541 tty->port->itty = tty;
1544 * Structures all installed ... call the ldisc open routines.
1545 * If we fail here just call release_tty to clean up. No need
1546 * to decrement the use counts, as release_tty doesn't care.
1548 retval = tty_ldisc_setup(tty, tty->link);
1550 goto err_release_tty;
1551 /* Return the tty locked so that it cannot vanish under the caller */
1556 free_tty_struct(tty);
1558 module_put(driver->owner);
1559 return ERR_PTR(retval);
1561 /* call the tty release_tty routine to clean out this slot */
1564 tty_info_ratelimited(tty, "ldisc open failed (%d), clearing slot %d\n",
1566 release_tty(tty, idx);
1567 return ERR_PTR(retval);
1570 static void tty_free_termios(struct tty_struct *tty)
1572 struct ktermios *tp;
1573 int idx = tty->index;
1575 /* If the port is going to reset then it has no termios to save */
1576 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1579 /* Stash the termios data */
1580 tp = tty->driver->termios[idx];
1582 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1585 tty->driver->termios[idx] = tp;
1591 * tty_flush_works - flush all works of a tty/pty pair
1592 * @tty: tty device to flush works for (or either end of a pty pair)
1594 * Sync flush all works belonging to @tty (and the 'other' tty).
1596 static void tty_flush_works(struct tty_struct *tty)
1598 flush_work(&tty->SAK_work);
1599 flush_work(&tty->hangup_work);
1601 flush_work(&tty->link->SAK_work);
1602 flush_work(&tty->link->hangup_work);
1607 * release_one_tty - release tty structure memory
1608 * @kref: kref of tty we are obliterating
1610 * Releases memory associated with a tty structure, and clears out the
1611 * driver table slots. This function is called when a device is no longer
1612 * in use. It also gets called when setup of a device fails.
1615 * takes the file list lock internally when working on the list
1616 * of ttys that the driver keeps.
1618 * This method gets called from a work queue so that the driver private
1619 * cleanup ops can sleep (needed for USB at least)
1621 static void release_one_tty(struct work_struct *work)
1623 struct tty_struct *tty =
1624 container_of(work, struct tty_struct, hangup_work);
1625 struct tty_driver *driver = tty->driver;
1626 struct module *owner = driver->owner;
1628 if (tty->ops->cleanup)
1629 tty->ops->cleanup(tty);
1632 tty_driver_kref_put(driver);
1635 spin_lock(&tty_files_lock);
1636 list_del_init(&tty->tty_files);
1637 spin_unlock(&tty_files_lock);
1640 put_pid(tty->session);
1641 free_tty_struct(tty);
1644 static void queue_release_one_tty(struct kref *kref)
1646 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1648 /* The hangup queue is now free so we can reuse it rather than
1649 waste a chunk of memory for each port */
1650 INIT_WORK(&tty->hangup_work, release_one_tty);
1651 schedule_work(&tty->hangup_work);
1655 * tty_kref_put - release a tty kref
1658 * Release a reference to a tty device and if need be let the kref
1659 * layer destruct the object for us
1662 void tty_kref_put(struct tty_struct *tty)
1665 kref_put(&tty->kref, queue_release_one_tty);
1667 EXPORT_SYMBOL(tty_kref_put);
1670 * release_tty - release tty structure memory
1672 * Release both @tty and a possible linked partner (think pty pair),
1673 * and decrement the refcount of the backing module.
1677 * takes the file list lock internally when working on the list
1678 * of ttys that the driver keeps.
1681 static void release_tty(struct tty_struct *tty, int idx)
1683 /* This should always be true but check for the moment */
1684 WARN_ON(tty->index != idx);
1685 WARN_ON(!mutex_is_locked(&tty_mutex));
1686 if (tty->ops->shutdown)
1687 tty->ops->shutdown(tty);
1688 tty_free_termios(tty);
1689 tty_driver_remove_tty(tty->driver, tty);
1690 tty->port->itty = NULL;
1692 tty->link->port->itty = NULL;
1693 tty_buffer_cancel_work(tty->port);
1695 tty_kref_put(tty->link);
1700 * tty_release_checks - check a tty before real release
1701 * @tty: tty to check
1702 * @o_tty: link of @tty (if any)
1703 * @idx: index of the tty
1705 * Performs some paranoid checking before true release of the @tty.
1706 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1708 static int tty_release_checks(struct tty_struct *tty, int idx)
1710 #ifdef TTY_PARANOIA_CHECK
1711 if (idx < 0 || idx >= tty->driver->num) {
1712 tty_debug(tty, "bad idx %d\n", idx);
1716 /* not much to check for devpts */
1717 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1720 if (tty != tty->driver->ttys[idx]) {
1721 tty_debug(tty, "bad driver table[%d] = %p\n",
1722 idx, tty->driver->ttys[idx]);
1725 if (tty->driver->other) {
1726 struct tty_struct *o_tty = tty->link;
1728 if (o_tty != tty->driver->other->ttys[idx]) {
1729 tty_debug(tty, "bad other table[%d] = %p\n",
1730 idx, tty->driver->other->ttys[idx]);
1733 if (o_tty->link != tty) {
1734 tty_debug(tty, "bad link = %p\n", o_tty->link);
1743 * tty_release - vfs callback for close
1744 * @inode: inode of tty
1745 * @filp: file pointer for handle to tty
1747 * Called the last time each file handle is closed that references
1748 * this tty. There may however be several such references.
1751 * Takes bkl. See tty_release_dev
1753 * Even releasing the tty structures is a tricky business.. We have
1754 * to be very careful that the structures are all released at the
1755 * same time, as interrupts might otherwise get the wrong pointers.
1757 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1758 * lead to double frees or releasing memory still in use.
1761 int tty_release(struct inode *inode, struct file *filp)
1763 struct tty_struct *tty = file_tty(filp);
1764 struct tty_struct *o_tty = NULL;
1765 int do_sleep, final;
1770 if (tty_paranoia_check(tty, inode, __func__))
1774 check_tty_count(tty, __func__);
1776 __tty_fasync(-1, filp, 0);
1779 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1780 tty->driver->subtype == PTY_TYPE_MASTER)
1783 if (tty_release_checks(tty, idx)) {
1788 tty_debug_hangup(tty, "releasing (count=%d)\n", tty->count);
1790 if (tty->ops->close)
1791 tty->ops->close(tty, filp);
1793 /* If tty is pty master, lock the slave pty (stable lock order) */
1794 tty_lock_slave(o_tty);
1797 * Sanity check: if tty->count is going to zero, there shouldn't be
1798 * any waiters on tty->read_wait or tty->write_wait. We test the
1799 * wait queues and kick everyone out _before_ actually starting to
1800 * close. This ensures that we won't block while releasing the tty
1803 * The test for the o_tty closing is necessary, since the master and
1804 * slave sides may close in any order. If the slave side closes out
1805 * first, its count will be one, since the master side holds an open.
1806 * Thus this test wouldn't be triggered at the time the slave closed,
1812 if (tty->count <= 1) {
1813 if (waitqueue_active(&tty->read_wait)) {
1814 wake_up_poll(&tty->read_wait, POLLIN);
1817 if (waitqueue_active(&tty->write_wait)) {
1818 wake_up_poll(&tty->write_wait, POLLOUT);
1822 if (o_tty && o_tty->count <= 1) {
1823 if (waitqueue_active(&o_tty->read_wait)) {
1824 wake_up_poll(&o_tty->read_wait, POLLIN);
1827 if (waitqueue_active(&o_tty->write_wait)) {
1828 wake_up_poll(&o_tty->write_wait, POLLOUT);
1837 tty_warn(tty, "read/write wait queue active!\n");
1839 schedule_timeout_killable(timeout);
1840 if (timeout < 120 * HZ)
1841 timeout = 2 * timeout + 1;
1843 timeout = MAX_SCHEDULE_TIMEOUT;
1847 if (--o_tty->count < 0) {
1848 tty_warn(tty, "bad slave count (%d)\n", o_tty->count);
1852 if (--tty->count < 0) {
1853 tty_warn(tty, "bad tty->count (%d)\n", tty->count);
1858 * We've decremented tty->count, so we need to remove this file
1859 * descriptor off the tty->tty_files list; this serves two
1861 * - check_tty_count sees the correct number of file descriptors
1862 * associated with this tty.
1863 * - do_tty_hangup no longer sees this file descriptor as
1864 * something that needs to be handled for hangups.
1869 * Perform some housekeeping before deciding whether to return.
1871 * If _either_ side is closing, make sure there aren't any
1872 * processes that still think tty or o_tty is their controlling
1876 read_lock(&tasklist_lock);
1877 session_clear_tty(tty->session);
1879 session_clear_tty(o_tty->session);
1880 read_unlock(&tasklist_lock);
1883 /* check whether both sides are closing ... */
1884 final = !tty->count && !(o_tty && o_tty->count);
1886 tty_unlock_slave(o_tty);
1889 /* At this point, the tty->count == 0 should ensure a dead tty
1890 cannot be re-opened by a racing opener */
1895 tty_debug_hangup(tty, "final close\n");
1897 * Ask the line discipline code to release its structures
1899 tty_ldisc_release(tty);
1901 /* Wait for pending work before tty destruction commmences */
1902 tty_flush_works(tty);
1904 tty_debug_hangup(tty, "freeing structure\n");
1906 * The release_tty function takes care of the details of clearing
1907 * the slots and preserving the termios structure. The tty_unlock_pair
1908 * should be safe as we keep a kref while the tty is locked (so the
1909 * unlock never unlocks a freed tty).
1911 mutex_lock(&tty_mutex);
1912 release_tty(tty, idx);
1913 mutex_unlock(&tty_mutex);
1919 * tty_open_current_tty - get locked tty of current task
1920 * @device: device number
1921 * @filp: file pointer to tty
1922 * @return: locked tty of the current task iff @device is /dev/tty
1924 * Performs a re-open of the current task's controlling tty.
1926 * We cannot return driver and index like for the other nodes because
1927 * devpts will not work then. It expects inodes to be from devpts FS.
1929 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1931 struct tty_struct *tty;
1934 if (device != MKDEV(TTYAUX_MAJOR, 0))
1937 tty = get_current_tty();
1939 return ERR_PTR(-ENXIO);
1941 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1944 tty_kref_put(tty); /* safe to drop the kref now */
1946 retval = tty_reopen(tty);
1949 tty = ERR_PTR(retval);
1955 * tty_lookup_driver - lookup a tty driver for a given device file
1956 * @device: device number
1957 * @filp: file pointer to tty
1958 * @noctty: set if the device should not become a controlling tty
1959 * @index: index for the device in the @return driver
1960 * @return: driver for this inode (with increased refcount)
1962 * If @return is not erroneous, the caller is responsible to decrement the
1963 * refcount by tty_driver_kref_put.
1965 * Locking: tty_mutex protects get_tty_driver
1967 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1970 struct tty_driver *driver;
1974 case MKDEV(TTY_MAJOR, 0): {
1975 extern struct tty_driver *console_driver;
1976 driver = tty_driver_kref_get(console_driver);
1977 *index = fg_console;
1981 case MKDEV(TTYAUX_MAJOR, 1): {
1982 struct tty_driver *console_driver = console_device(index);
1983 if (console_driver) {
1984 driver = tty_driver_kref_get(console_driver);
1986 /* Don't let /dev/console block */
1987 filp->f_flags |= O_NONBLOCK;
1991 return ERR_PTR(-ENODEV);
1994 driver = get_tty_driver(device, index);
1996 return ERR_PTR(-ENODEV);
2003 * tty_open_by_driver - open a tty device
2004 * @device: dev_t of device to open
2005 * @inode: inode of device file
2006 * @filp: file pointer to tty
2008 * Performs the driver lookup, checks for a reopen, or otherwise
2009 * performs the first-time tty initialization.
2011 * Returns the locked initialized or re-opened &tty_struct
2013 * Claims the global tty_mutex to serialize:
2014 * - concurrent first-time tty initialization
2015 * - concurrent tty driver removal w/ lookup
2016 * - concurrent tty removal from driver table
2018 static struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode,
2021 struct tty_struct *tty;
2022 struct tty_driver *driver = NULL;
2026 mutex_lock(&tty_mutex);
2027 driver = tty_lookup_driver(device, filp, &index);
2028 if (IS_ERR(driver)) {
2029 mutex_unlock(&tty_mutex);
2030 return ERR_CAST(driver);
2033 /* check whether we're reopening an existing tty */
2034 tty = tty_driver_lookup_tty(driver, inode, index);
2036 mutex_unlock(&tty_mutex);
2041 mutex_unlock(&tty_mutex);
2042 retval = tty_lock_interruptible(tty);
2044 if (retval == -EINTR)
2045 retval = -ERESTARTSYS;
2046 tty = ERR_PTR(retval);
2049 /* safe to drop the kref from tty_driver_lookup_tty() */
2051 retval = tty_reopen(tty);
2054 tty = ERR_PTR(retval);
2056 } else { /* Returns with the tty_lock held for now */
2057 tty = tty_init_dev(driver, index);
2058 mutex_unlock(&tty_mutex);
2061 tty_driver_kref_put(driver);
2066 * tty_open - open a tty device
2067 * @inode: inode of device file
2068 * @filp: file pointer to tty
2070 * tty_open and tty_release keep up the tty count that contains the
2071 * number of opens done on a tty. We cannot use the inode-count, as
2072 * different inodes might point to the same tty.
2074 * Open-counting is needed for pty masters, as well as for keeping
2075 * track of serial lines: DTR is dropped when the last close happens.
2076 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2078 * The termios state of a pty is reset on first open so that
2079 * settings don't persist across reuse.
2081 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
2082 * tty->count should protect the rest.
2083 * ->siglock protects ->signal/->sighand
2085 * Note: the tty_unlock/lock cases without a ref are only safe due to
2089 static int tty_open(struct inode *inode, struct file *filp)
2091 struct tty_struct *tty;
2093 dev_t device = inode->i_rdev;
2094 unsigned saved_flags = filp->f_flags;
2096 nonseekable_open(inode, filp);
2099 retval = tty_alloc_file(filp);
2103 tty = tty_open_current_tty(device, filp);
2105 tty = tty_open_by_driver(device, inode, filp);
2108 tty_free_file(filp);
2109 retval = PTR_ERR(tty);
2110 if (retval != -EAGAIN || signal_pending(current))
2116 tty_add_file(tty, filp);
2118 check_tty_count(tty, __func__);
2119 tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
2122 retval = tty->ops->open(tty, filp);
2125 filp->f_flags = saved_flags;
2128 tty_debug_hangup(tty, "open error %d, releasing\n", retval);
2130 tty_unlock(tty); /* need to call tty_release without BTM */
2131 tty_release(inode, filp);
2132 if (retval != -ERESTARTSYS)
2135 if (signal_pending(current))
2140 * Need to reset f_op in case a hangup happened.
2142 if (tty_hung_up_p(filp))
2143 filp->f_op = &tty_fops;
2146 clear_bit(TTY_HUPPED, &tty->flags);
2149 read_lock(&tasklist_lock);
2150 spin_lock_irq(¤t->sighand->siglock);
2151 noctty = (filp->f_flags & O_NOCTTY) ||
2152 device == MKDEV(TTY_MAJOR, 0) ||
2153 device == MKDEV(TTYAUX_MAJOR, 1) ||
2154 (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2155 tty->driver->subtype == PTY_TYPE_MASTER);
2158 current->signal->leader &&
2159 !current->signal->tty &&
2160 tty->session == NULL) {
2162 * Don't let a process that only has write access to the tty
2163 * obtain the privileges associated with having a tty as
2164 * controlling terminal (being able to reopen it with full
2165 * access through /dev/tty, being able to perform pushback).
2166 * Many distributions set the group of all ttys to "tty" and
2167 * grant write-only access to all terminals for setgid tty
2168 * binaries, which should not imply full privileges on all ttys.
2170 * This could theoretically break old code that performs open()
2171 * on a write-only file descriptor. In that case, it might be
2172 * necessary to also permit this if
2173 * inode_permission(inode, MAY_READ) == 0.
2175 if (filp->f_mode & FMODE_READ)
2176 __proc_set_tty(tty);
2178 spin_unlock_irq(¤t->sighand->siglock);
2179 read_unlock(&tasklist_lock);
2187 * tty_poll - check tty status
2188 * @filp: file being polled
2189 * @wait: poll wait structures to update
2191 * Call the line discipline polling method to obtain the poll
2192 * status of the device.
2194 * Locking: locks called line discipline but ldisc poll method
2195 * may be re-entered freely by other callers.
2198 static unsigned int tty_poll(struct file *filp, poll_table *wait)
2200 struct tty_struct *tty = file_tty(filp);
2201 struct tty_ldisc *ld;
2204 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2207 ld = tty_ldisc_ref_wait(tty);
2209 return hung_up_tty_poll(filp, wait);
2211 ret = ld->ops->poll(tty, filp, wait);
2212 tty_ldisc_deref(ld);
2216 static int __tty_fasync(int fd, struct file *filp, int on)
2218 struct tty_struct *tty = file_tty(filp);
2219 struct tty_ldisc *ldisc;
2220 unsigned long flags;
2223 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2226 retval = fasync_helper(fd, filp, on, &tty->fasync);
2230 ldisc = tty_ldisc_ref(tty);
2232 if (ldisc->ops->fasync)
2233 ldisc->ops->fasync(tty, on);
2234 tty_ldisc_deref(ldisc);
2241 spin_lock_irqsave(&tty->ctrl_lock, flags);
2244 type = PIDTYPE_PGID;
2246 pid = task_pid(current);
2250 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2251 __f_setown(filp, pid, type, 0);
2259 static int tty_fasync(int fd, struct file *filp, int on)
2261 struct tty_struct *tty = file_tty(filp);
2265 retval = __tty_fasync(fd, filp, on);
2272 * tiocsti - fake input character
2273 * @tty: tty to fake input into
2274 * @p: pointer to character
2276 * Fake input to a tty device. Does the necessary locking and
2279 * FIXME: does not honour flow control ??
2282 * Called functions take tty_ldiscs_lock
2283 * current->signal->tty check is safe without locks
2285 * FIXME: may race normal receive processing
2288 static int tiocsti(struct tty_struct *tty, char __user *p)
2291 struct tty_ldisc *ld;
2293 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2295 if (get_user(ch, p))
2297 tty_audit_tiocsti(tty, ch);
2298 ld = tty_ldisc_ref_wait(tty);
2301 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2302 tty_ldisc_deref(ld);
2307 * tiocgwinsz - implement window query ioctl
2309 * @arg: user buffer for result
2311 * Copies the kernel idea of the window size into the user buffer.
2313 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2317 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2321 mutex_lock(&tty->winsize_mutex);
2322 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2323 mutex_unlock(&tty->winsize_mutex);
2325 return err ? -EFAULT: 0;
2329 * tty_do_resize - resize event
2330 * @tty: tty being resized
2331 * @rows: rows (character)
2332 * @cols: cols (character)
2334 * Update the termios variables and send the necessary signals to
2335 * peform a terminal resize correctly
2338 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2343 mutex_lock(&tty->winsize_mutex);
2344 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2347 /* Signal the foreground process group */
2348 pgrp = tty_get_pgrp(tty);
2350 kill_pgrp(pgrp, SIGWINCH, 1);
2355 mutex_unlock(&tty->winsize_mutex);
2358 EXPORT_SYMBOL(tty_do_resize);
2361 * tiocswinsz - implement window size set ioctl
2362 * @tty; tty side of tty
2363 * @arg: user buffer for result
2365 * Copies the user idea of the window size to the kernel. Traditionally
2366 * this is just advisory information but for the Linux console it
2367 * actually has driver level meaning and triggers a VC resize.
2370 * Driver dependent. The default do_resize method takes the
2371 * tty termios mutex and ctrl_lock. The console takes its own lock
2372 * then calls into the default method.
2375 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2377 struct winsize tmp_ws;
2378 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2381 if (tty->ops->resize)
2382 return tty->ops->resize(tty, &tmp_ws);
2384 return tty_do_resize(tty, &tmp_ws);
2388 * tioccons - allow admin to move logical console
2389 * @file: the file to become console
2391 * Allow the administrator to move the redirected console device
2393 * Locking: uses redirect_lock to guard the redirect information
2396 static int tioccons(struct file *file)
2398 if (!capable(CAP_SYS_ADMIN))
2400 if (file->f_op->write == redirected_tty_write) {
2402 spin_lock(&redirect_lock);
2405 spin_unlock(&redirect_lock);
2410 spin_lock(&redirect_lock);
2412 spin_unlock(&redirect_lock);
2415 redirect = get_file(file);
2416 spin_unlock(&redirect_lock);
2421 * fionbio - non blocking ioctl
2422 * @file: file to set blocking value
2423 * @p: user parameter
2425 * Historical tty interfaces had a blocking control ioctl before
2426 * the generic functionality existed. This piece of history is preserved
2427 * in the expected tty API of posix OS's.
2429 * Locking: none, the open file handle ensures it won't go away.
2432 static int fionbio(struct file *file, int __user *p)
2436 if (get_user(nonblock, p))
2439 spin_lock(&file->f_lock);
2441 file->f_flags |= O_NONBLOCK;
2443 file->f_flags &= ~O_NONBLOCK;
2444 spin_unlock(&file->f_lock);
2449 * tiocsctty - set controlling tty
2450 * @tty: tty structure
2451 * @arg: user argument
2453 * This ioctl is used to manage job control. It permits a session
2454 * leader to set this tty as the controlling tty for the session.
2457 * Takes tty_lock() to serialize proc_set_tty() for this tty
2458 * Takes tasklist_lock internally to walk sessions
2459 * Takes ->siglock() when updating signal->tty
2462 static int tiocsctty(struct tty_struct *tty, struct file *file, int arg)
2467 read_lock(&tasklist_lock);
2469 if (current->signal->leader && (task_session(current) == tty->session))
2473 * The process must be a session leader and
2474 * not have a controlling tty already.
2476 if (!current->signal->leader || current->signal->tty) {
2483 * This tty is already the controlling
2484 * tty for another session group!
2486 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2490 session_clear_tty(tty->session);
2497 /* See the comment in tty_open(). */
2498 if ((file->f_mode & FMODE_READ) == 0 && !capable(CAP_SYS_ADMIN)) {
2505 read_unlock(&tasklist_lock);
2511 * tty_get_pgrp - return a ref counted pgrp pid
2514 * Returns a refcounted instance of the pid struct for the process
2515 * group controlling the tty.
2518 struct pid *tty_get_pgrp(struct tty_struct *tty)
2520 unsigned long flags;
2523 spin_lock_irqsave(&tty->ctrl_lock, flags);
2524 pgrp = get_pid(tty->pgrp);
2525 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2529 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2532 * This checks not only the pgrp, but falls back on the pid if no
2533 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
2536 * The caller must hold rcu lock or the tasklist lock.
2538 static struct pid *session_of_pgrp(struct pid *pgrp)
2540 struct task_struct *p;
2541 struct pid *sid = NULL;
2543 p = pid_task(pgrp, PIDTYPE_PGID);
2545 p = pid_task(pgrp, PIDTYPE_PID);
2547 sid = task_session(p);
2553 * tiocgpgrp - get process group
2554 * @tty: tty passed by user
2555 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2558 * Obtain the process group of the tty. If there is no process group
2561 * Locking: none. Reference to current->signal->tty is safe.
2564 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2569 * (tty == real_tty) is a cheap way of
2570 * testing if the tty is NOT a master pty.
2572 if (tty == real_tty && current->signal->tty != real_tty)
2574 pid = tty_get_pgrp(real_tty);
2575 ret = put_user(pid_vnr(pid), p);
2581 * tiocspgrp - attempt to set process group
2582 * @tty: tty passed by user
2583 * @real_tty: tty side device matching tty passed by user
2586 * Set the process group of the tty to the session passed. Only
2587 * permitted where the tty session is our session.
2589 * Locking: RCU, ctrl lock
2592 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2596 int retval = tty_check_change(real_tty);
2602 if (!current->signal->tty ||
2603 (current->signal->tty != real_tty) ||
2604 (real_tty->session != task_session(current)))
2606 if (get_user(pgrp_nr, p))
2611 pgrp = find_vpid(pgrp_nr);
2616 if (session_of_pgrp(pgrp) != task_session(current))
2619 spin_lock_irq(&tty->ctrl_lock);
2620 put_pid(real_tty->pgrp);
2621 real_tty->pgrp = get_pid(pgrp);
2622 spin_unlock_irq(&tty->ctrl_lock);
2629 * tiocgsid - get session id
2630 * @tty: tty passed by user
2631 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2632 * @p: pointer to returned session id
2634 * Obtain the session id of the tty. If there is no session
2637 * Locking: none. Reference to current->signal->tty is safe.
2640 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2643 * (tty == real_tty) is a cheap way of
2644 * testing if the tty is NOT a master pty.
2646 if (tty == real_tty && current->signal->tty != real_tty)
2648 if (!real_tty->session)
2650 return put_user(pid_vnr(real_tty->session), p);
2654 * tiocsetd - set line discipline
2656 * @p: pointer to user data
2658 * Set the line discipline according to user request.
2660 * Locking: see tty_set_ldisc, this function is just a helper
2663 static int tiocsetd(struct tty_struct *tty, int __user *p)
2668 if (get_user(disc, p))
2671 ret = tty_set_ldisc(tty, disc);
2677 * tiocgetd - get line discipline
2679 * @p: pointer to user data
2681 * Retrieves the line discipline id directly from the ldisc.
2683 * Locking: waits for ldisc reference (in case the line discipline
2684 * is changing or the tty is being hungup)
2687 static int tiocgetd(struct tty_struct *tty, int __user *p)
2689 struct tty_ldisc *ld;
2692 ld = tty_ldisc_ref_wait(tty);
2695 ret = put_user(ld->ops->num, p);
2696 tty_ldisc_deref(ld);
2701 * send_break - performed time break
2702 * @tty: device to break on
2703 * @duration: timeout in mS
2705 * Perform a timed break on hardware that lacks its own driver level
2706 * timed break functionality.
2709 * atomic_write_lock serializes
2713 static int send_break(struct tty_struct *tty, unsigned int duration)
2717 if (tty->ops->break_ctl == NULL)
2720 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2721 retval = tty->ops->break_ctl(tty, duration);
2723 /* Do the work ourselves */
2724 if (tty_write_lock(tty, 0) < 0)
2726 retval = tty->ops->break_ctl(tty, -1);
2729 if (!signal_pending(current))
2730 msleep_interruptible(duration);
2731 retval = tty->ops->break_ctl(tty, 0);
2733 tty_write_unlock(tty);
2734 if (signal_pending(current))
2741 * tty_tiocmget - get modem status
2743 * @file: user file pointer
2744 * @p: pointer to result
2746 * Obtain the modem status bits from the tty driver if the feature
2747 * is supported. Return -EINVAL if it is not available.
2749 * Locking: none (up to the driver)
2752 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2754 int retval = -EINVAL;
2756 if (tty->ops->tiocmget) {
2757 retval = tty->ops->tiocmget(tty);
2760 retval = put_user(retval, p);
2766 * tty_tiocmset - set modem status
2768 * @cmd: command - clear bits, set bits or set all
2769 * @p: pointer to desired bits
2771 * Set the modem status bits from the tty driver if the feature
2772 * is supported. Return -EINVAL if it is not available.
2774 * Locking: none (up to the driver)
2777 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2781 unsigned int set, clear, val;
2783 if (tty->ops->tiocmset == NULL)
2786 retval = get_user(val, p);
2802 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2803 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2804 return tty->ops->tiocmset(tty, set, clear);
2807 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2809 int retval = -EINVAL;
2810 struct serial_icounter_struct icount;
2811 memset(&icount, 0, sizeof(icount));
2812 if (tty->ops->get_icount)
2813 retval = tty->ops->get_icount(tty, &icount);
2816 if (copy_to_user(arg, &icount, sizeof(icount)))
2821 static void tty_warn_deprecated_flags(struct serial_struct __user *ss)
2823 static DEFINE_RATELIMIT_STATE(depr_flags,
2824 DEFAULT_RATELIMIT_INTERVAL,
2825 DEFAULT_RATELIMIT_BURST);
2826 char comm[TASK_COMM_LEN];
2829 if (get_user(flags, &ss->flags))
2832 flags &= ASYNC_DEPRECATED;
2834 if (flags && __ratelimit(&depr_flags))
2835 pr_warning("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2836 __func__, get_task_comm(comm, current), flags);
2840 * if pty, return the slave side (real_tty)
2841 * otherwise, return self
2843 static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2845 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2846 tty->driver->subtype == PTY_TYPE_MASTER)
2852 * Split this up, as gcc can choke on it otherwise..
2854 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2856 struct tty_struct *tty = file_tty(file);
2857 struct tty_struct *real_tty;
2858 void __user *p = (void __user *)arg;
2860 struct tty_ldisc *ld;
2862 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2865 real_tty = tty_pair_get_tty(tty);
2868 * Factor out some common prep work
2876 retval = tty_check_change(tty);
2879 if (cmd != TIOCCBRK) {
2880 tty_wait_until_sent(tty, 0);
2881 if (signal_pending(current))
2892 return tiocsti(tty, p);
2894 return tiocgwinsz(real_tty, p);
2896 return tiocswinsz(real_tty, p);
2898 return real_tty != tty ? -EINVAL : tioccons(file);
2900 return fionbio(file, p);
2902 set_bit(TTY_EXCLUSIVE, &tty->flags);
2905 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2909 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2910 return put_user(excl, (int __user *)p);
2913 if (current->signal->tty != tty)
2918 return tiocsctty(real_tty, file, arg);
2920 return tiocgpgrp(tty, real_tty, p);
2922 return tiocspgrp(tty, real_tty, p);
2924 return tiocgsid(tty, real_tty, p);
2926 return tiocgetd(tty, p);
2928 return tiocsetd(tty, p);
2930 if (!capable(CAP_SYS_ADMIN))
2936 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2937 return put_user(ret, (unsigned int __user *)p);
2942 case TIOCSBRK: /* Turn break on, unconditionally */
2943 if (tty->ops->break_ctl)
2944 return tty->ops->break_ctl(tty, -1);
2946 case TIOCCBRK: /* Turn break off, unconditionally */
2947 if (tty->ops->break_ctl)
2948 return tty->ops->break_ctl(tty, 0);
2950 case TCSBRK: /* SVID version: non-zero arg --> no break */
2951 /* non-zero arg means wait for all output data
2952 * to be sent (performed above) but don't send break.
2953 * This is used by the tcdrain() termios function.
2956 return send_break(tty, 250);
2958 case TCSBRKP: /* support for POSIX tcsendbreak() */
2959 return send_break(tty, arg ? arg*100 : 250);
2962 return tty_tiocmget(tty, p);
2966 return tty_tiocmset(tty, cmd, p);
2968 retval = tty_tiocgicount(tty, p);
2969 /* For the moment allow fall through to the old method */
2970 if (retval != -EINVAL)
2977 /* flush tty buffer and allow ldisc to process ioctl */
2978 tty_buffer_flush(tty, NULL);
2983 tty_warn_deprecated_flags(p);
2986 if (tty->ops->ioctl) {
2987 retval = tty->ops->ioctl(tty, cmd, arg);
2988 if (retval != -ENOIOCTLCMD)
2991 ld = tty_ldisc_ref_wait(tty);
2993 return hung_up_tty_ioctl(file, cmd, arg);
2995 if (ld->ops->ioctl) {
2996 retval = ld->ops->ioctl(tty, file, cmd, arg);
2997 if (retval == -ENOIOCTLCMD)
3000 tty_ldisc_deref(ld);
3004 #ifdef CONFIG_COMPAT
3005 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
3008 struct tty_struct *tty = file_tty(file);
3009 struct tty_ldisc *ld;
3010 int retval = -ENOIOCTLCMD;
3012 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
3015 if (tty->ops->compat_ioctl) {
3016 retval = tty->ops->compat_ioctl(tty, cmd, arg);
3017 if (retval != -ENOIOCTLCMD)
3021 ld = tty_ldisc_ref_wait(tty);
3023 return hung_up_tty_compat_ioctl(file, cmd, arg);
3024 if (ld->ops->compat_ioctl)
3025 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
3027 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
3028 tty_ldisc_deref(ld);
3034 static int this_tty(const void *t, struct file *file, unsigned fd)
3036 if (likely(file->f_op->read != tty_read))
3038 return file_tty(file) != t ? 0 : fd + 1;
3042 * This implements the "Secure Attention Key" --- the idea is to
3043 * prevent trojan horses by killing all processes associated with this
3044 * tty when the user hits the "Secure Attention Key". Required for
3045 * super-paranoid applications --- see the Orange Book for more details.
3047 * This code could be nicer; ideally it should send a HUP, wait a few
3048 * seconds, then send a INT, and then a KILL signal. But you then
3049 * have to coordinate with the init process, since all processes associated
3050 * with the current tty must be dead before the new getty is allowed
3053 * Now, if it would be correct ;-/ The current code has a nasty hole -
3054 * it doesn't catch files in flight. We may send the descriptor to ourselves
3055 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
3057 * Nasty bug: do_SAK is being called in interrupt context. This can
3058 * deadlock. We punt it up to process context. AKPM - 16Mar2001
3060 void __do_SAK(struct tty_struct *tty)
3065 struct task_struct *g, *p;
3066 struct pid *session;
3071 session = tty->session;
3073 tty_ldisc_flush(tty);
3075 tty_driver_flush_buffer(tty);
3077 read_lock(&tasklist_lock);
3078 /* Kill the entire session */
3079 do_each_pid_task(session, PIDTYPE_SID, p) {
3080 tty_notice(tty, "SAK: killed process %d (%s): by session\n",
3081 task_pid_nr(p), p->comm);
3082 send_sig(SIGKILL, p, 1);
3083 } while_each_pid_task(session, PIDTYPE_SID, p);
3085 /* Now kill any processes that happen to have the tty open */
3086 do_each_thread(g, p) {
3087 if (p->signal->tty == tty) {
3088 tty_notice(tty, "SAK: killed process %d (%s): by controlling tty\n",
3089 task_pid_nr(p), p->comm);
3090 send_sig(SIGKILL, p, 1);
3094 i = iterate_fd(p->files, 0, this_tty, tty);
3096 tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n",
3097 task_pid_nr(p), p->comm, i - 1);
3098 force_sig(SIGKILL, p);
3101 } while_each_thread(g, p);
3102 read_unlock(&tasklist_lock);
3106 static void do_SAK_work(struct work_struct *work)
3108 struct tty_struct *tty =
3109 container_of(work, struct tty_struct, SAK_work);
3114 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3115 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3116 * the values which we write to it will be identical to the values which it
3117 * already has. --akpm
3119 void do_SAK(struct tty_struct *tty)
3123 schedule_work(&tty->SAK_work);
3126 EXPORT_SYMBOL(do_SAK);
3128 static int dev_match_devt(struct device *dev, const void *data)
3130 const dev_t *devt = data;
3131 return dev->devt == *devt;
3134 /* Must put_device() after it's unused! */
3135 static struct device *tty_get_device(struct tty_struct *tty)
3137 dev_t devt = tty_devnum(tty);
3138 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
3145 * This subroutine allocates and initializes a tty structure.
3147 * Locking: none - tty in question is not exposed at this point
3150 struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
3152 struct tty_struct *tty;
3154 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
3158 kref_init(&tty->kref);
3159 tty->magic = TTY_MAGIC;
3160 tty_ldisc_init(tty);
3161 tty->session = NULL;
3163 mutex_init(&tty->legacy_mutex);
3164 mutex_init(&tty->throttle_mutex);
3165 init_rwsem(&tty->termios_rwsem);
3166 mutex_init(&tty->winsize_mutex);
3167 init_ldsem(&tty->ldisc_sem);
3168 init_waitqueue_head(&tty->write_wait);
3169 init_waitqueue_head(&tty->read_wait);
3170 INIT_WORK(&tty->hangup_work, do_tty_hangup);
3171 mutex_init(&tty->atomic_write_lock);
3172 spin_lock_init(&tty->ctrl_lock);
3173 spin_lock_init(&tty->flow_lock);
3174 INIT_LIST_HEAD(&tty->tty_files);
3175 INIT_WORK(&tty->SAK_work, do_SAK_work);
3177 tty->driver = driver;
3178 tty->ops = driver->ops;
3180 tty_line_name(driver, idx, tty->name);
3181 tty->dev = tty_get_device(tty);
3187 * tty_put_char - write one character to a tty
3191 * Write one byte to the tty using the provided put_char method
3192 * if present. Returns the number of characters successfully output.
3194 * Note: the specific put_char operation in the driver layer may go
3195 * away soon. Don't call it directly, use this method
3198 int tty_put_char(struct tty_struct *tty, unsigned char ch)
3200 if (tty->ops->put_char)
3201 return tty->ops->put_char(tty, ch);
3202 return tty->ops->write(tty, &ch, 1);
3204 EXPORT_SYMBOL_GPL(tty_put_char);
3206 struct class *tty_class;
3208 static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3209 unsigned int index, unsigned int count)
3213 /* init here, since reused cdevs cause crashes */
3214 driver->cdevs[index] = cdev_alloc();
3215 if (!driver->cdevs[index])
3217 driver->cdevs[index]->ops = &tty_fops;
3218 driver->cdevs[index]->owner = driver->owner;
3219 err = cdev_add(driver->cdevs[index], dev, count);
3221 kobject_put(&driver->cdevs[index]->kobj);
3226 * tty_register_device - register a tty device
3227 * @driver: the tty driver that describes the tty device
3228 * @index: the index in the tty driver for this tty device
3229 * @device: a struct device that is associated with this tty device.
3230 * This field is optional, if there is no known struct device
3231 * for this tty device it can be set to NULL safely.
3233 * Returns a pointer to the struct device for this tty device
3234 * (or ERR_PTR(-EFOO) on error).
3236 * This call is required to be made to register an individual tty device
3237 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3238 * that bit is not set, this function should not be called by a tty
3244 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3245 struct device *device)
3247 return tty_register_device_attr(driver, index, device, NULL, NULL);
3249 EXPORT_SYMBOL(tty_register_device);
3251 static void tty_device_create_release(struct device *dev)
3253 dev_dbg(dev, "releasing...\n");
3258 * tty_register_device_attr - register a tty device
3259 * @driver: the tty driver that describes the tty device
3260 * @index: the index in the tty driver for this tty device
3261 * @device: a struct device that is associated with this tty device.
3262 * This field is optional, if there is no known struct device
3263 * for this tty device it can be set to NULL safely.
3264 * @drvdata: Driver data to be set to device.
3265 * @attr_grp: Attribute group to be set on device.
3267 * Returns a pointer to the struct device for this tty device
3268 * (or ERR_PTR(-EFOO) on error).
3270 * This call is required to be made to register an individual tty device
3271 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3272 * that bit is not set, this function should not be called by a tty
3277 struct device *tty_register_device_attr(struct tty_driver *driver,
3278 unsigned index, struct device *device,
3280 const struct attribute_group **attr_grp)
3283 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3284 struct device *dev = NULL;
3285 int retval = -ENODEV;
3288 if (index >= driver->num) {
3289 pr_err("%s: Attempt to register invalid tty line number (%d)\n",
3290 driver->name, index);
3291 return ERR_PTR(-EINVAL);
3294 if (driver->type == TTY_DRIVER_TYPE_PTY)
3295 pty_line_name(driver, index, name);
3297 tty_line_name(driver, index, name);
3299 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3300 retval = tty_cdev_add(driver, devt, index, 1);
3306 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3313 dev->class = tty_class;
3314 dev->parent = device;
3315 dev->release = tty_device_create_release;
3316 dev_set_name(dev, "%s", name);
3317 dev->groups = attr_grp;
3318 dev_set_drvdata(dev, drvdata);
3320 retval = device_register(dev);
3329 cdev_del(driver->cdevs[index]);
3330 driver->cdevs[index] = NULL;
3332 return ERR_PTR(retval);
3334 EXPORT_SYMBOL_GPL(tty_register_device_attr);
3337 * tty_unregister_device - unregister a tty device
3338 * @driver: the tty driver that describes the tty device
3339 * @index: the index in the tty driver for this tty device
3341 * If a tty device is registered with a call to tty_register_device() then
3342 * this function must be called when the tty device is gone.
3347 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3349 device_destroy(tty_class,
3350 MKDEV(driver->major, driver->minor_start) + index);
3351 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3352 cdev_del(driver->cdevs[index]);
3353 driver->cdevs[index] = NULL;
3356 EXPORT_SYMBOL(tty_unregister_device);
3359 * __tty_alloc_driver -- allocate tty driver
3360 * @lines: count of lines this driver can handle at most
3361 * @owner: module which is repsonsible for this driver
3362 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3364 * This should not be called directly, some of the provided macros should be
3365 * used instead. Use IS_ERR and friends on @retval.
3367 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3368 unsigned long flags)
3370 struct tty_driver *driver;
3371 unsigned int cdevs = 1;
3374 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3375 return ERR_PTR(-EINVAL);
3377 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3379 return ERR_PTR(-ENOMEM);
3381 kref_init(&driver->kref);
3382 driver->magic = TTY_DRIVER_MAGIC;
3383 driver->num = lines;
3384 driver->owner = owner;
3385 driver->flags = flags;
3387 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3388 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3390 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3392 if (!driver->ttys || !driver->termios) {
3398 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3399 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3401 if (!driver->ports) {
3408 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3409 if (!driver->cdevs) {
3416 kfree(driver->ports);
3417 kfree(driver->ttys);
3418 kfree(driver->termios);
3419 kfree(driver->cdevs);
3421 return ERR_PTR(err);
3423 EXPORT_SYMBOL(__tty_alloc_driver);
3425 static void destruct_tty_driver(struct kref *kref)
3427 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3429 struct ktermios *tp;
3431 if (driver->flags & TTY_DRIVER_INSTALLED) {
3433 * Free the termios and termios_locked structures because
3434 * we don't want to get memory leaks when modular tty
3435 * drivers are removed from the kernel.
3437 for (i = 0; i < driver->num; i++) {
3438 tp = driver->termios[i];
3440 driver->termios[i] = NULL;
3443 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3444 tty_unregister_device(driver, i);
3446 proc_tty_unregister_driver(driver);
3447 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3448 cdev_del(driver->cdevs[0]);
3450 kfree(driver->cdevs);
3451 kfree(driver->ports);
3452 kfree(driver->termios);
3453 kfree(driver->ttys);
3457 void tty_driver_kref_put(struct tty_driver *driver)
3459 kref_put(&driver->kref, destruct_tty_driver);
3461 EXPORT_SYMBOL(tty_driver_kref_put);
3463 void tty_set_operations(struct tty_driver *driver,
3464 const struct tty_operations *op)
3468 EXPORT_SYMBOL(tty_set_operations);
3470 void put_tty_driver(struct tty_driver *d)
3472 tty_driver_kref_put(d);
3474 EXPORT_SYMBOL(put_tty_driver);
3477 * Called by a tty driver to register itself.
3479 int tty_register_driver(struct tty_driver *driver)
3486 if (!driver->major) {
3487 error = alloc_chrdev_region(&dev, driver->minor_start,
3488 driver->num, driver->name);
3490 driver->major = MAJOR(dev);
3491 driver->minor_start = MINOR(dev);
3494 dev = MKDEV(driver->major, driver->minor_start);
3495 error = register_chrdev_region(dev, driver->num, driver->name);
3500 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3501 error = tty_cdev_add(driver, dev, 0, driver->num);
3503 goto err_unreg_char;
3506 mutex_lock(&tty_mutex);
3507 list_add(&driver->tty_drivers, &tty_drivers);
3508 mutex_unlock(&tty_mutex);
3510 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3511 for (i = 0; i < driver->num; i++) {
3512 d = tty_register_device(driver, i, NULL);
3515 goto err_unreg_devs;
3519 proc_tty_register_driver(driver);
3520 driver->flags |= TTY_DRIVER_INSTALLED;
3524 for (i--; i >= 0; i--)
3525 tty_unregister_device(driver, i);
3527 mutex_lock(&tty_mutex);
3528 list_del(&driver->tty_drivers);
3529 mutex_unlock(&tty_mutex);
3532 unregister_chrdev_region(dev, driver->num);
3536 EXPORT_SYMBOL(tty_register_driver);
3539 * Called by a tty driver to unregister itself.
3541 int tty_unregister_driver(struct tty_driver *driver)
3545 if (driver->refcount)
3548 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3550 mutex_lock(&tty_mutex);
3551 list_del(&driver->tty_drivers);
3552 mutex_unlock(&tty_mutex);
3556 EXPORT_SYMBOL(tty_unregister_driver);
3558 dev_t tty_devnum(struct tty_struct *tty)
3560 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3562 EXPORT_SYMBOL(tty_devnum);
3564 void tty_default_fops(struct file_operations *fops)
3570 * Initialize the console device. This is called *early*, so
3571 * we can't necessarily depend on lots of kernel help here.
3572 * Just do some early initializations, and do the complex setup
3575 void __init console_init(void)
3579 /* Setup the default TTY line discipline. */
3583 * set up the console device so that later boot sequences can
3584 * inform about problems etc..
3586 call = __con_initcall_start;
3587 while (call < __con_initcall_end) {
3593 static char *tty_devnode(struct device *dev, umode_t *mode)
3597 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3598 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3603 static int __init tty_class_init(void)
3605 tty_class = class_create(THIS_MODULE, "tty");
3606 if (IS_ERR(tty_class))
3607 return PTR_ERR(tty_class);
3608 tty_class->devnode = tty_devnode;
3612 postcore_initcall(tty_class_init);
3614 /* 3/2004 jmc: why do these devices exist? */
3615 static struct cdev tty_cdev, console_cdev;
3617 static ssize_t show_cons_active(struct device *dev,
3618 struct device_attribute *attr, char *buf)
3620 struct console *cs[16];
3626 for_each_console(c) {
3631 if ((c->flags & CON_ENABLED) == 0)
3634 if (i >= ARRAY_SIZE(cs))
3638 int index = cs[i]->index;
3639 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3641 /* don't resolve tty0 as some programs depend on it */
3642 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3643 count += tty_line_name(drv, index, buf + count);
3645 count += sprintf(buf + count, "%s%d",
3646 cs[i]->name, cs[i]->index);
3648 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3654 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3656 static struct attribute *cons_dev_attrs[] = {
3657 &dev_attr_active.attr,
3661 ATTRIBUTE_GROUPS(cons_dev);
3663 static struct device *consdev;
3665 void console_sysfs_notify(void)
3668 sysfs_notify(&consdev->kobj, NULL, "active");
3672 * Ok, now we can initialize the rest of the tty devices and can count
3673 * on memory allocations, interrupts etc..
3675 int __init tty_init(void)
3677 cdev_init(&tty_cdev, &tty_fops);
3678 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3679 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3680 panic("Couldn't register /dev/tty driver\n");
3681 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3683 cdev_init(&console_cdev, &console_fops);
3684 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3685 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3686 panic("Couldn't register /dev/console driver\n");
3687 consdev = device_create_with_groups(tty_class, NULL,
3688 MKDEV(TTYAUX_MAJOR, 1), NULL,
3689 cons_dev_groups, "console");
3690 if (IS_ERR(consdev))
3694 vty_init(&console_fops);