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,
127 /* .c_line = N_TTY, */
130 EXPORT_SYMBOL(tty_std_termios);
132 /* This list gets poked at by procfs and various bits of boot up code. This
133 could do with some rationalisation such as pulling the tty proc function
136 LIST_HEAD(tty_drivers); /* linked list of tty drivers */
138 /* Mutex to protect creating and releasing a tty. This is shared with
139 vt.c for deeply disgusting hack reasons */
140 DEFINE_MUTEX(tty_mutex);
141 EXPORT_SYMBOL(tty_mutex);
143 /* Spinlock to protect the tty->tty_files list */
144 DEFINE_SPINLOCK(tty_files_lock);
146 static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
147 static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
148 ssize_t redirected_tty_write(struct file *, const char __user *,
150 static unsigned int tty_poll(struct file *, poll_table *);
151 static int tty_open(struct inode *, struct file *);
152 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
154 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
157 #define tty_compat_ioctl NULL
159 static int __tty_fasync(int fd, struct file *filp, int on);
160 static int tty_fasync(int fd, struct file *filp, int on);
161 static void release_tty(struct tty_struct *tty, int idx);
164 * free_tty_struct - free a disused tty
165 * @tty: tty struct to free
167 * Free the write buffers, tty queue and tty memory itself.
169 * Locking: none. Must be called after tty is definitely unused
172 static void free_tty_struct(struct tty_struct *tty)
174 tty_ldisc_deinit(tty);
175 put_device(tty->dev);
176 kfree(tty->write_buf);
177 tty->magic = 0xDEADDEAD;
181 static inline struct tty_struct *file_tty(struct file *file)
183 return ((struct tty_file_private *)file->private_data)->tty;
186 int tty_alloc_file(struct file *file)
188 struct tty_file_private *priv;
190 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
194 file->private_data = priv;
199 /* Associate a new file with the tty structure */
200 void tty_add_file(struct tty_struct *tty, struct file *file)
202 struct tty_file_private *priv = file->private_data;
207 spin_lock(&tty_files_lock);
208 list_add(&priv->list, &tty->tty_files);
209 spin_unlock(&tty_files_lock);
213 * tty_free_file - free file->private_data
215 * This shall be used only for fail path handling when tty_add_file was not
218 void tty_free_file(struct file *file)
220 struct tty_file_private *priv = file->private_data;
222 file->private_data = NULL;
226 /* Delete file from its tty */
227 static void tty_del_file(struct file *file)
229 struct tty_file_private *priv = file->private_data;
231 spin_lock(&tty_files_lock);
232 list_del(&priv->list);
233 spin_unlock(&tty_files_lock);
238 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
241 * tty_name - return tty naming
242 * @tty: tty structure
244 * Convert a tty structure into a name. The name reflects the kernel
245 * naming policy and if udev is in use may not reflect user space
250 const char *tty_name(const struct tty_struct *tty)
252 if (!tty) /* Hmm. NULL pointer. That's fun. */
257 EXPORT_SYMBOL(tty_name);
259 const char *tty_driver_name(const struct tty_struct *tty)
261 if (!tty || !tty->driver)
263 return tty->driver->name;
266 static int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
269 #ifdef TTY_PARANOIA_CHECK
271 pr_warn("(%d:%d): %s: NULL tty\n",
272 imajor(inode), iminor(inode), routine);
275 if (tty->magic != TTY_MAGIC) {
276 pr_warn("(%d:%d): %s: bad magic number\n",
277 imajor(inode), iminor(inode), routine);
284 /* Caller must hold tty_lock */
285 static int check_tty_count(struct tty_struct *tty, const char *routine)
287 #ifdef CHECK_TTY_COUNT
291 spin_lock(&tty_files_lock);
292 list_for_each(p, &tty->tty_files) {
295 spin_unlock(&tty_files_lock);
296 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
297 tty->driver->subtype == PTY_TYPE_SLAVE &&
298 tty->link && tty->link->count)
300 if (tty->count != count) {
301 tty_warn(tty, "%s: tty->count(%d) != #fd's(%d)\n",
302 routine, tty->count, count);
310 * get_tty_driver - find device of a tty
311 * @dev_t: device identifier
312 * @index: returns the index of the tty
314 * This routine returns a tty driver structure, given a device number
315 * and also passes back the index number.
317 * Locking: caller must hold tty_mutex
320 static struct tty_driver *get_tty_driver(dev_t device, int *index)
322 struct tty_driver *p;
324 list_for_each_entry(p, &tty_drivers, tty_drivers) {
325 dev_t base = MKDEV(p->major, p->minor_start);
326 if (device < base || device >= base + p->num)
328 *index = device - base;
329 return tty_driver_kref_get(p);
334 #ifdef CONFIG_CONSOLE_POLL
337 * tty_find_polling_driver - find device of a polled tty
338 * @name: name string to match
339 * @line: pointer to resulting tty line nr
341 * This routine returns a tty driver structure, given a name
342 * and the condition that the tty driver is capable of polled
345 struct tty_driver *tty_find_polling_driver(char *name, int *line)
347 struct tty_driver *p, *res = NULL;
352 for (str = name; *str; str++)
353 if ((*str >= '0' && *str <= '9') || *str == ',')
359 tty_line = simple_strtoul(str, &str, 10);
361 mutex_lock(&tty_mutex);
362 /* Search through the tty devices to look for a match */
363 list_for_each_entry(p, &tty_drivers, tty_drivers) {
364 if (strncmp(name, p->name, len) != 0)
372 if (tty_line >= 0 && tty_line < p->num && p->ops &&
373 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
374 res = tty_driver_kref_get(p);
379 mutex_unlock(&tty_mutex);
383 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
387 * tty_check_change - check for POSIX terminal changes
390 * If we try to write to, or set the state of, a terminal and we're
391 * not in the foreground, send a SIGTTOU. If the signal is blocked or
392 * ignored, go ahead and perform the operation. (POSIX 7.2)
397 int __tty_check_change(struct tty_struct *tty, int sig)
400 struct pid *pgrp, *tty_pgrp;
403 if (current->signal->tty != tty)
407 pgrp = task_pgrp(current);
409 spin_lock_irqsave(&tty->ctrl_lock, flags);
410 tty_pgrp = tty->pgrp;
411 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
413 if (tty_pgrp && pgrp != tty->pgrp) {
414 if (is_ignored(sig)) {
417 } else if (is_current_pgrp_orphaned())
420 kill_pgrp(pgrp, sig, 1);
421 set_thread_flag(TIF_SIGPENDING);
428 tty_warn(tty, "sig=%d, tty->pgrp == NULL!\n", sig);
433 int tty_check_change(struct tty_struct *tty)
435 return __tty_check_change(tty, SIGTTOU);
437 EXPORT_SYMBOL(tty_check_change);
439 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
440 size_t count, loff_t *ppos)
445 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
446 size_t count, loff_t *ppos)
451 /* No kernel lock held - none needed ;) */
452 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
454 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
457 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
460 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
463 static long hung_up_tty_compat_ioctl(struct file *file,
464 unsigned int cmd, unsigned long arg)
466 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
469 static const struct file_operations tty_fops = {
474 .unlocked_ioctl = tty_ioctl,
475 .compat_ioctl = tty_compat_ioctl,
477 .release = tty_release,
478 .fasync = tty_fasync,
481 static const struct file_operations console_fops = {
484 .write = redirected_tty_write,
486 .unlocked_ioctl = tty_ioctl,
487 .compat_ioctl = tty_compat_ioctl,
489 .release = tty_release,
490 .fasync = tty_fasync,
493 static const struct file_operations hung_up_tty_fops = {
495 .read = hung_up_tty_read,
496 .write = hung_up_tty_write,
497 .poll = hung_up_tty_poll,
498 .unlocked_ioctl = hung_up_tty_ioctl,
499 .compat_ioctl = hung_up_tty_compat_ioctl,
500 .release = tty_release,
503 static DEFINE_SPINLOCK(redirect_lock);
504 static struct file *redirect;
507 void proc_clear_tty(struct task_struct *p)
510 struct tty_struct *tty;
511 spin_lock_irqsave(&p->sighand->siglock, flags);
512 tty = p->signal->tty;
513 p->signal->tty = NULL;
514 spin_unlock_irqrestore(&p->sighand->siglock, flags);
519 * proc_set_tty - set the controlling terminal
521 * Only callable by the session leader and only if it does not already have
522 * a controlling terminal.
524 * Caller must hold: tty_lock()
525 * a readlock on tasklist_lock
528 static void __proc_set_tty(struct tty_struct *tty)
532 spin_lock_irqsave(&tty->ctrl_lock, flags);
534 * The session and fg pgrp references will be non-NULL if
535 * tiocsctty() is stealing the controlling tty
537 put_pid(tty->session);
539 tty->pgrp = get_pid(task_pgrp(current));
540 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
541 tty->session = get_pid(task_session(current));
542 if (current->signal->tty) {
543 tty_debug(tty, "current tty %s not NULL!!\n",
544 current->signal->tty->name);
545 tty_kref_put(current->signal->tty);
547 put_pid(current->signal->tty_old_pgrp);
548 current->signal->tty = tty_kref_get(tty);
549 current->signal->tty_old_pgrp = NULL;
552 static void proc_set_tty(struct tty_struct *tty)
554 spin_lock_irq(¤t->sighand->siglock);
556 spin_unlock_irq(¤t->sighand->siglock);
559 struct tty_struct *get_current_tty(void)
561 struct tty_struct *tty;
564 spin_lock_irqsave(¤t->sighand->siglock, flags);
565 tty = tty_kref_get(current->signal->tty);
566 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
569 EXPORT_SYMBOL_GPL(get_current_tty);
571 static void session_clear_tty(struct pid *session)
573 struct task_struct *p;
574 do_each_pid_task(session, PIDTYPE_SID, p) {
576 } while_each_pid_task(session, PIDTYPE_SID, p);
580 * tty_wakeup - request more data
583 * Internal and external helper for wakeups of tty. This function
584 * informs the line discipline if present that the driver is ready
585 * to receive more output data.
588 void tty_wakeup(struct tty_struct *tty)
590 struct tty_ldisc *ld;
592 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
593 ld = tty_ldisc_ref(tty);
595 if (ld->ops->write_wakeup)
596 ld->ops->write_wakeup(tty);
600 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
603 EXPORT_SYMBOL_GPL(tty_wakeup);
606 * tty_signal_session_leader - sends SIGHUP to session leader
607 * @tty controlling tty
608 * @exit_session if non-zero, signal all foreground group processes
610 * Send SIGHUP and SIGCONT to the session leader and its process group.
611 * Optionally, signal all processes in the foreground process group.
613 * Returns the number of processes in the session with this tty
614 * as their controlling terminal. This value is used to drop
615 * tty references for those processes.
617 static int tty_signal_session_leader(struct tty_struct *tty, int exit_session)
619 struct task_struct *p;
621 struct pid *tty_pgrp = NULL;
623 read_lock(&tasklist_lock);
625 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
626 spin_lock_irq(&p->sighand->siglock);
627 if (p->signal->tty == tty) {
628 p->signal->tty = NULL;
629 /* We defer the dereferences outside fo
633 if (!p->signal->leader) {
634 spin_unlock_irq(&p->sighand->siglock);
637 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
638 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
639 put_pid(p->signal->tty_old_pgrp); /* A noop */
640 spin_lock(&tty->ctrl_lock);
641 tty_pgrp = get_pid(tty->pgrp);
643 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
644 spin_unlock(&tty->ctrl_lock);
645 spin_unlock_irq(&p->sighand->siglock);
646 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
648 read_unlock(&tasklist_lock);
652 kill_pgrp(tty_pgrp, SIGHUP, exit_session);
660 * __tty_hangup - actual handler for hangup events
663 * This can be called by a "kworker" kernel thread. That is process
664 * synchronous but doesn't hold any locks, so we need to make sure we
665 * have the appropriate locks for what we're doing.
667 * The hangup event clears any pending redirections onto the hung up
668 * device. It ensures future writes will error and it does the needed
669 * line discipline hangup and signal delivery. The tty object itself
674 * redirect lock for undoing redirection
675 * file list lock for manipulating list of ttys
676 * tty_ldiscs_lock from called functions
677 * termios_rwsem resetting termios data
678 * tasklist_lock to walk task list for hangup event
679 * ->siglock to protect ->signal/->sighand
681 static void __tty_hangup(struct tty_struct *tty, int exit_session)
683 struct file *cons_filp = NULL;
684 struct file *filp, *f = NULL;
685 struct tty_file_private *priv;
686 int closecount = 0, n;
693 spin_lock(&redirect_lock);
694 if (redirect && file_tty(redirect) == tty) {
698 spin_unlock(&redirect_lock);
702 if (test_bit(TTY_HUPPED, &tty->flags)) {
707 /* inuse_filps is protected by the single tty lock,
708 this really needs to change if we want to flush the
709 workqueue with the lock held */
710 check_tty_count(tty, "tty_hangup");
712 spin_lock(&tty_files_lock);
713 /* This breaks for file handles being sent over AF_UNIX sockets ? */
714 list_for_each_entry(priv, &tty->tty_files, list) {
716 if (filp->f_op->write == redirected_tty_write)
718 if (filp->f_op->write != tty_write)
721 __tty_fasync(-1, filp, 0); /* can't block */
722 filp->f_op = &hung_up_tty_fops;
724 spin_unlock(&tty_files_lock);
726 refs = tty_signal_session_leader(tty, exit_session);
727 /* Account for the p->signal references we killed */
731 tty_ldisc_hangup(tty, cons_filp != NULL);
733 spin_lock_irq(&tty->ctrl_lock);
734 clear_bit(TTY_THROTTLED, &tty->flags);
735 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
736 put_pid(tty->session);
740 tty->ctrl_status = 0;
741 spin_unlock_irq(&tty->ctrl_lock);
744 * If one of the devices matches a console pointer, we
745 * cannot just call hangup() because that will cause
746 * tty->count and state->count to go out of sync.
747 * So we just call close() the right number of times.
751 for (n = 0; n < closecount; n++)
752 tty->ops->close(tty, cons_filp);
753 } else if (tty->ops->hangup)
754 tty->ops->hangup(tty);
756 * We don't want to have driver/ldisc interactions beyond the ones
757 * we did here. The driver layer expects no calls after ->hangup()
758 * from the ldisc side, which is now guaranteed.
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))
1479 return tty_ldisc_reinit(tty, tty->termios.c_line);
1485 * tty_init_dev - initialise a tty device
1486 * @driver: tty driver we are opening a device on
1487 * @idx: device index
1488 * @ret_tty: returned tty structure
1490 * Prepare a tty device. This may not be a "new" clean device but
1491 * could also be an active device. The pty drivers require special
1492 * handling because of this.
1495 * The function is called under the tty_mutex, which
1496 * protects us from the tty struct or driver itself going away.
1498 * On exit the tty device has the line discipline attached and
1499 * a reference count of 1. If a pair was created for pty/tty use
1500 * and the other was a pty master then it too has a reference count of 1.
1502 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1503 * failed open. The new code protects the open with a mutex, so it's
1504 * really quite straightforward. The mutex locking can probably be
1505 * relaxed for the (most common) case of reopening a tty.
1508 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1510 struct tty_struct *tty;
1514 * First time open is complex, especially for PTY devices.
1515 * This code guarantees that either everything succeeds and the
1516 * TTY is ready for operation, or else the table slots are vacated
1517 * and the allocated memory released. (Except that the termios
1518 * and locked termios may be retained.)
1521 if (!try_module_get(driver->owner))
1522 return ERR_PTR(-ENODEV);
1524 tty = alloc_tty_struct(driver, idx);
1527 goto err_module_put;
1531 retval = tty_driver_install_tty(driver, tty);
1536 tty->port = driver->ports[idx];
1538 WARN_RATELIMIT(!tty->port,
1539 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1540 __func__, tty->driver->name);
1542 tty->port->itty = tty;
1545 * Structures all installed ... call the ldisc open routines.
1546 * If we fail here just call release_tty to clean up. No need
1547 * to decrement the use counts, as release_tty doesn't care.
1549 retval = tty_ldisc_setup(tty, tty->link);
1551 goto err_release_tty;
1552 /* Return the tty locked so that it cannot vanish under the caller */
1557 free_tty_struct(tty);
1559 module_put(driver->owner);
1560 return ERR_PTR(retval);
1562 /* call the tty release_tty routine to clean out this slot */
1565 tty_info_ratelimited(tty, "ldisc open failed (%d), clearing slot %d\n",
1567 release_tty(tty, idx);
1568 return ERR_PTR(retval);
1571 static void tty_free_termios(struct tty_struct *tty)
1573 struct ktermios *tp;
1574 int idx = tty->index;
1576 /* If the port is going to reset then it has no termios to save */
1577 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1580 /* Stash the termios data */
1581 tp = tty->driver->termios[idx];
1583 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1586 tty->driver->termios[idx] = tp;
1592 * tty_flush_works - flush all works of a tty/pty pair
1593 * @tty: tty device to flush works for (or either end of a pty pair)
1595 * Sync flush all works belonging to @tty (and the 'other' tty).
1597 static void tty_flush_works(struct tty_struct *tty)
1599 flush_work(&tty->SAK_work);
1600 flush_work(&tty->hangup_work);
1602 flush_work(&tty->link->SAK_work);
1603 flush_work(&tty->link->hangup_work);
1608 * release_one_tty - release tty structure memory
1609 * @kref: kref of tty we are obliterating
1611 * Releases memory associated with a tty structure, and clears out the
1612 * driver table slots. This function is called when a device is no longer
1613 * in use. It also gets called when setup of a device fails.
1616 * takes the file list lock internally when working on the list
1617 * of ttys that the driver keeps.
1619 * This method gets called from a work queue so that the driver private
1620 * cleanup ops can sleep (needed for USB at least)
1622 static void release_one_tty(struct work_struct *work)
1624 struct tty_struct *tty =
1625 container_of(work, struct tty_struct, hangup_work);
1626 struct tty_driver *driver = tty->driver;
1627 struct module *owner = driver->owner;
1629 if (tty->ops->cleanup)
1630 tty->ops->cleanup(tty);
1633 tty_driver_kref_put(driver);
1636 spin_lock(&tty_files_lock);
1637 list_del_init(&tty->tty_files);
1638 spin_unlock(&tty_files_lock);
1641 put_pid(tty->session);
1642 free_tty_struct(tty);
1645 static void queue_release_one_tty(struct kref *kref)
1647 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1649 /* The hangup queue is now free so we can reuse it rather than
1650 waste a chunk of memory for each port */
1651 INIT_WORK(&tty->hangup_work, release_one_tty);
1652 schedule_work(&tty->hangup_work);
1656 * tty_kref_put - release a tty kref
1659 * Release a reference to a tty device and if need be let the kref
1660 * layer destruct the object for us
1663 void tty_kref_put(struct tty_struct *tty)
1666 kref_put(&tty->kref, queue_release_one_tty);
1668 EXPORT_SYMBOL(tty_kref_put);
1671 * release_tty - release tty structure memory
1673 * Release both @tty and a possible linked partner (think pty pair),
1674 * and decrement the refcount of the backing module.
1678 * takes the file list lock internally when working on the list
1679 * of ttys that the driver keeps.
1682 static void release_tty(struct tty_struct *tty, int idx)
1684 /* This should always be true but check for the moment */
1685 WARN_ON(tty->index != idx);
1686 WARN_ON(!mutex_is_locked(&tty_mutex));
1687 if (tty->ops->shutdown)
1688 tty->ops->shutdown(tty);
1689 tty_free_termios(tty);
1690 tty_driver_remove_tty(tty->driver, tty);
1691 tty->port->itty = NULL;
1693 tty->link->port->itty = NULL;
1694 tty_buffer_cancel_work(tty->port);
1696 tty_kref_put(tty->link);
1701 * tty_release_checks - check a tty before real release
1702 * @tty: tty to check
1703 * @o_tty: link of @tty (if any)
1704 * @idx: index of the tty
1706 * Performs some paranoid checking before true release of the @tty.
1707 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1709 static int tty_release_checks(struct tty_struct *tty, int idx)
1711 #ifdef TTY_PARANOIA_CHECK
1712 if (idx < 0 || idx >= tty->driver->num) {
1713 tty_debug(tty, "bad idx %d\n", idx);
1717 /* not much to check for devpts */
1718 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1721 if (tty != tty->driver->ttys[idx]) {
1722 tty_debug(tty, "bad driver table[%d] = %p\n",
1723 idx, tty->driver->ttys[idx]);
1726 if (tty->driver->other) {
1727 struct tty_struct *o_tty = tty->link;
1729 if (o_tty != tty->driver->other->ttys[idx]) {
1730 tty_debug(tty, "bad other table[%d] = %p\n",
1731 idx, tty->driver->other->ttys[idx]);
1734 if (o_tty->link != tty) {
1735 tty_debug(tty, "bad link = %p\n", o_tty->link);
1744 * tty_release - vfs callback for close
1745 * @inode: inode of tty
1746 * @filp: file pointer for handle to tty
1748 * Called the last time each file handle is closed that references
1749 * this tty. There may however be several such references.
1752 * Takes bkl. See tty_release_dev
1754 * Even releasing the tty structures is a tricky business.. We have
1755 * to be very careful that the structures are all released at the
1756 * same time, as interrupts might otherwise get the wrong pointers.
1758 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1759 * lead to double frees or releasing memory still in use.
1762 int tty_release(struct inode *inode, struct file *filp)
1764 struct tty_struct *tty = file_tty(filp);
1765 struct tty_struct *o_tty = NULL;
1766 int do_sleep, final;
1771 if (tty_paranoia_check(tty, inode, __func__))
1775 check_tty_count(tty, __func__);
1777 __tty_fasync(-1, filp, 0);
1780 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1781 tty->driver->subtype == PTY_TYPE_MASTER)
1784 if (tty_release_checks(tty, idx)) {
1789 tty_debug_hangup(tty, "releasing (count=%d)\n", tty->count);
1791 if (tty->ops->close)
1792 tty->ops->close(tty, filp);
1794 /* If tty is pty master, lock the slave pty (stable lock order) */
1795 tty_lock_slave(o_tty);
1798 * Sanity check: if tty->count is going to zero, there shouldn't be
1799 * any waiters on tty->read_wait or tty->write_wait. We test the
1800 * wait queues and kick everyone out _before_ actually starting to
1801 * close. This ensures that we won't block while releasing the tty
1804 * The test for the o_tty closing is necessary, since the master and
1805 * slave sides may close in any order. If the slave side closes out
1806 * first, its count will be one, since the master side holds an open.
1807 * Thus this test wouldn't be triggered at the time the slave closed,
1813 if (tty->count <= 1) {
1814 if (waitqueue_active(&tty->read_wait)) {
1815 wake_up_poll(&tty->read_wait, POLLIN);
1818 if (waitqueue_active(&tty->write_wait)) {
1819 wake_up_poll(&tty->write_wait, POLLOUT);
1823 if (o_tty && o_tty->count <= 1) {
1824 if (waitqueue_active(&o_tty->read_wait)) {
1825 wake_up_poll(&o_tty->read_wait, POLLIN);
1828 if (waitqueue_active(&o_tty->write_wait)) {
1829 wake_up_poll(&o_tty->write_wait, POLLOUT);
1838 tty_warn(tty, "read/write wait queue active!\n");
1840 schedule_timeout_killable(timeout);
1841 if (timeout < 120 * HZ)
1842 timeout = 2 * timeout + 1;
1844 timeout = MAX_SCHEDULE_TIMEOUT;
1848 if (--o_tty->count < 0) {
1849 tty_warn(tty, "bad slave count (%d)\n", o_tty->count);
1853 if (--tty->count < 0) {
1854 tty_warn(tty, "bad tty->count (%d)\n", tty->count);
1859 * We've decremented tty->count, so we need to remove this file
1860 * descriptor off the tty->tty_files list; this serves two
1862 * - check_tty_count sees the correct number of file descriptors
1863 * associated with this tty.
1864 * - do_tty_hangup no longer sees this file descriptor as
1865 * something that needs to be handled for hangups.
1870 * Perform some housekeeping before deciding whether to return.
1872 * If _either_ side is closing, make sure there aren't any
1873 * processes that still think tty or o_tty is their controlling
1877 read_lock(&tasklist_lock);
1878 session_clear_tty(tty->session);
1880 session_clear_tty(o_tty->session);
1881 read_unlock(&tasklist_lock);
1884 /* check whether both sides are closing ... */
1885 final = !tty->count && !(o_tty && o_tty->count);
1887 tty_unlock_slave(o_tty);
1890 /* At this point, the tty->count == 0 should ensure a dead tty
1891 cannot be re-opened by a racing opener */
1896 tty_debug_hangup(tty, "final close\n");
1898 * Ask the line discipline code to release its structures
1900 tty_ldisc_release(tty);
1902 /* Wait for pending work before tty destruction commmences */
1903 tty_flush_works(tty);
1905 tty_debug_hangup(tty, "freeing structure\n");
1907 * The release_tty function takes care of the details of clearing
1908 * the slots and preserving the termios structure. The tty_unlock_pair
1909 * should be safe as we keep a kref while the tty is locked (so the
1910 * unlock never unlocks a freed tty).
1912 mutex_lock(&tty_mutex);
1913 release_tty(tty, idx);
1914 mutex_unlock(&tty_mutex);
1920 * tty_open_current_tty - get locked tty of current task
1921 * @device: device number
1922 * @filp: file pointer to tty
1923 * @return: locked tty of the current task iff @device is /dev/tty
1925 * Performs a re-open of the current task's controlling tty.
1927 * We cannot return driver and index like for the other nodes because
1928 * devpts will not work then. It expects inodes to be from devpts FS.
1930 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1932 struct tty_struct *tty;
1935 if (device != MKDEV(TTYAUX_MAJOR, 0))
1938 tty = get_current_tty();
1940 return ERR_PTR(-ENXIO);
1942 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1945 tty_kref_put(tty); /* safe to drop the kref now */
1947 retval = tty_reopen(tty);
1950 tty = ERR_PTR(retval);
1956 * tty_lookup_driver - lookup a tty driver for a given device file
1957 * @device: device number
1958 * @filp: file pointer to tty
1959 * @noctty: set if the device should not become a controlling tty
1960 * @index: index for the device in the @return driver
1961 * @return: driver for this inode (with increased refcount)
1963 * If @return is not erroneous, the caller is responsible to decrement the
1964 * refcount by tty_driver_kref_put.
1966 * Locking: tty_mutex protects get_tty_driver
1968 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1971 struct tty_driver *driver;
1975 case MKDEV(TTY_MAJOR, 0): {
1976 extern struct tty_driver *console_driver;
1977 driver = tty_driver_kref_get(console_driver);
1978 *index = fg_console;
1982 case MKDEV(TTYAUX_MAJOR, 1): {
1983 struct tty_driver *console_driver = console_device(index);
1984 if (console_driver) {
1985 driver = tty_driver_kref_get(console_driver);
1987 /* Don't let /dev/console block */
1988 filp->f_flags |= O_NONBLOCK;
1992 return ERR_PTR(-ENODEV);
1995 driver = get_tty_driver(device, index);
1997 return ERR_PTR(-ENODEV);
2004 * tty_open_by_driver - open a tty device
2005 * @device: dev_t of device to open
2006 * @inode: inode of device file
2007 * @filp: file pointer to tty
2009 * Performs the driver lookup, checks for a reopen, or otherwise
2010 * performs the first-time tty initialization.
2012 * Returns the locked initialized or re-opened &tty_struct
2014 * Claims the global tty_mutex to serialize:
2015 * - concurrent first-time tty initialization
2016 * - concurrent tty driver removal w/ lookup
2017 * - concurrent tty removal from driver table
2019 static struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode,
2022 struct tty_struct *tty;
2023 struct tty_driver *driver = NULL;
2027 mutex_lock(&tty_mutex);
2028 driver = tty_lookup_driver(device, filp, &index);
2029 if (IS_ERR(driver)) {
2030 mutex_unlock(&tty_mutex);
2031 return ERR_CAST(driver);
2034 /* check whether we're reopening an existing tty */
2035 tty = tty_driver_lookup_tty(driver, inode, index);
2037 mutex_unlock(&tty_mutex);
2042 mutex_unlock(&tty_mutex);
2043 retval = tty_lock_interruptible(tty);
2045 if (retval == -EINTR)
2046 retval = -ERESTARTSYS;
2047 tty = ERR_PTR(retval);
2050 /* safe to drop the kref from tty_driver_lookup_tty() */
2052 retval = tty_reopen(tty);
2055 tty = ERR_PTR(retval);
2057 } else { /* Returns with the tty_lock held for now */
2058 tty = tty_init_dev(driver, index);
2059 mutex_unlock(&tty_mutex);
2062 tty_driver_kref_put(driver);
2067 * tty_open - open a tty device
2068 * @inode: inode of device file
2069 * @filp: file pointer to tty
2071 * tty_open and tty_release keep up the tty count that contains the
2072 * number of opens done on a tty. We cannot use the inode-count, as
2073 * different inodes might point to the same tty.
2075 * Open-counting is needed for pty masters, as well as for keeping
2076 * track of serial lines: DTR is dropped when the last close happens.
2077 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2079 * The termios state of a pty is reset on first open so that
2080 * settings don't persist across reuse.
2082 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
2083 * tty->count should protect the rest.
2084 * ->siglock protects ->signal/->sighand
2086 * Note: the tty_unlock/lock cases without a ref are only safe due to
2090 static int tty_open(struct inode *inode, struct file *filp)
2092 struct tty_struct *tty;
2094 dev_t device = inode->i_rdev;
2095 unsigned saved_flags = filp->f_flags;
2097 nonseekable_open(inode, filp);
2100 retval = tty_alloc_file(filp);
2104 tty = tty_open_current_tty(device, filp);
2106 tty = tty_open_by_driver(device, inode, filp);
2109 tty_free_file(filp);
2110 retval = PTR_ERR(tty);
2111 if (retval != -EAGAIN || signal_pending(current))
2117 tty_add_file(tty, filp);
2119 check_tty_count(tty, __func__);
2120 tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
2123 retval = tty->ops->open(tty, filp);
2126 filp->f_flags = saved_flags;
2129 tty_debug_hangup(tty, "open error %d, releasing\n", retval);
2131 tty_unlock(tty); /* need to call tty_release without BTM */
2132 tty_release(inode, filp);
2133 if (retval != -ERESTARTSYS)
2136 if (signal_pending(current))
2141 * Need to reset f_op in case a hangup happened.
2143 if (tty_hung_up_p(filp))
2144 filp->f_op = &tty_fops;
2147 clear_bit(TTY_HUPPED, &tty->flags);
2150 read_lock(&tasklist_lock);
2151 spin_lock_irq(¤t->sighand->siglock);
2152 noctty = (filp->f_flags & O_NOCTTY) ||
2153 device == MKDEV(TTY_MAJOR, 0) ||
2154 device == MKDEV(TTYAUX_MAJOR, 1) ||
2155 (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2156 tty->driver->subtype == PTY_TYPE_MASTER);
2159 current->signal->leader &&
2160 !current->signal->tty &&
2161 tty->session == NULL) {
2163 * Don't let a process that only has write access to the tty
2164 * obtain the privileges associated with having a tty as
2165 * controlling terminal (being able to reopen it with full
2166 * access through /dev/tty, being able to perform pushback).
2167 * Many distributions set the group of all ttys to "tty" and
2168 * grant write-only access to all terminals for setgid tty
2169 * binaries, which should not imply full privileges on all ttys.
2171 * This could theoretically break old code that performs open()
2172 * on a write-only file descriptor. In that case, it might be
2173 * necessary to also permit this if
2174 * inode_permission(inode, MAY_READ) == 0.
2176 if (filp->f_mode & FMODE_READ)
2177 __proc_set_tty(tty);
2179 spin_unlock_irq(¤t->sighand->siglock);
2180 read_unlock(&tasklist_lock);
2188 * tty_poll - check tty status
2189 * @filp: file being polled
2190 * @wait: poll wait structures to update
2192 * Call the line discipline polling method to obtain the poll
2193 * status of the device.
2195 * Locking: locks called line discipline but ldisc poll method
2196 * may be re-entered freely by other callers.
2199 static unsigned int tty_poll(struct file *filp, poll_table *wait)
2201 struct tty_struct *tty = file_tty(filp);
2202 struct tty_ldisc *ld;
2205 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2208 ld = tty_ldisc_ref_wait(tty);
2210 return hung_up_tty_poll(filp, wait);
2212 ret = ld->ops->poll(tty, filp, wait);
2213 tty_ldisc_deref(ld);
2217 static int __tty_fasync(int fd, struct file *filp, int on)
2219 struct tty_struct *tty = file_tty(filp);
2220 struct tty_ldisc *ldisc;
2221 unsigned long flags;
2224 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2227 retval = fasync_helper(fd, filp, on, &tty->fasync);
2231 ldisc = tty_ldisc_ref(tty);
2233 if (ldisc->ops->fasync)
2234 ldisc->ops->fasync(tty, on);
2235 tty_ldisc_deref(ldisc);
2242 spin_lock_irqsave(&tty->ctrl_lock, flags);
2245 type = PIDTYPE_PGID;
2247 pid = task_pid(current);
2251 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2252 __f_setown(filp, pid, type, 0);
2260 static int tty_fasync(int fd, struct file *filp, int on)
2262 struct tty_struct *tty = file_tty(filp);
2266 retval = __tty_fasync(fd, filp, on);
2273 * tiocsti - fake input character
2274 * @tty: tty to fake input into
2275 * @p: pointer to character
2277 * Fake input to a tty device. Does the necessary locking and
2280 * FIXME: does not honour flow control ??
2283 * Called functions take tty_ldiscs_lock
2284 * current->signal->tty check is safe without locks
2286 * FIXME: may race normal receive processing
2289 static int tiocsti(struct tty_struct *tty, char __user *p)
2292 struct tty_ldisc *ld;
2294 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2296 if (get_user(ch, p))
2298 tty_audit_tiocsti(tty, ch);
2299 ld = tty_ldisc_ref_wait(tty);
2302 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2303 tty_ldisc_deref(ld);
2308 * tiocgwinsz - implement window query ioctl
2310 * @arg: user buffer for result
2312 * Copies the kernel idea of the window size into the user buffer.
2314 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2318 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2322 mutex_lock(&tty->winsize_mutex);
2323 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2324 mutex_unlock(&tty->winsize_mutex);
2326 return err ? -EFAULT: 0;
2330 * tty_do_resize - resize event
2331 * @tty: tty being resized
2332 * @rows: rows (character)
2333 * @cols: cols (character)
2335 * Update the termios variables and send the necessary signals to
2336 * peform a terminal resize correctly
2339 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2344 mutex_lock(&tty->winsize_mutex);
2345 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2348 /* Signal the foreground process group */
2349 pgrp = tty_get_pgrp(tty);
2351 kill_pgrp(pgrp, SIGWINCH, 1);
2356 mutex_unlock(&tty->winsize_mutex);
2359 EXPORT_SYMBOL(tty_do_resize);
2362 * tiocswinsz - implement window size set ioctl
2363 * @tty; tty side of tty
2364 * @arg: user buffer for result
2366 * Copies the user idea of the window size to the kernel. Traditionally
2367 * this is just advisory information but for the Linux console it
2368 * actually has driver level meaning and triggers a VC resize.
2371 * Driver dependent. The default do_resize method takes the
2372 * tty termios mutex and ctrl_lock. The console takes its own lock
2373 * then calls into the default method.
2376 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2378 struct winsize tmp_ws;
2379 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2382 if (tty->ops->resize)
2383 return tty->ops->resize(tty, &tmp_ws);
2385 return tty_do_resize(tty, &tmp_ws);
2389 * tioccons - allow admin to move logical console
2390 * @file: the file to become console
2392 * Allow the administrator to move the redirected console device
2394 * Locking: uses redirect_lock to guard the redirect information
2397 static int tioccons(struct file *file)
2399 if (!capable(CAP_SYS_ADMIN))
2401 if (file->f_op->write == redirected_tty_write) {
2403 spin_lock(&redirect_lock);
2406 spin_unlock(&redirect_lock);
2411 spin_lock(&redirect_lock);
2413 spin_unlock(&redirect_lock);
2416 redirect = get_file(file);
2417 spin_unlock(&redirect_lock);
2422 * fionbio - non blocking ioctl
2423 * @file: file to set blocking value
2424 * @p: user parameter
2426 * Historical tty interfaces had a blocking control ioctl before
2427 * the generic functionality existed. This piece of history is preserved
2428 * in the expected tty API of posix OS's.
2430 * Locking: none, the open file handle ensures it won't go away.
2433 static int fionbio(struct file *file, int __user *p)
2437 if (get_user(nonblock, p))
2440 spin_lock(&file->f_lock);
2442 file->f_flags |= O_NONBLOCK;
2444 file->f_flags &= ~O_NONBLOCK;
2445 spin_unlock(&file->f_lock);
2450 * tiocsctty - set controlling tty
2451 * @tty: tty structure
2452 * @arg: user argument
2454 * This ioctl is used to manage job control. It permits a session
2455 * leader to set this tty as the controlling tty for the session.
2458 * Takes tty_lock() to serialize proc_set_tty() for this tty
2459 * Takes tasklist_lock internally to walk sessions
2460 * Takes ->siglock() when updating signal->tty
2463 static int tiocsctty(struct tty_struct *tty, struct file *file, int arg)
2468 read_lock(&tasklist_lock);
2470 if (current->signal->leader && (task_session(current) == tty->session))
2474 * The process must be a session leader and
2475 * not have a controlling tty already.
2477 if (!current->signal->leader || current->signal->tty) {
2484 * This tty is already the controlling
2485 * tty for another session group!
2487 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2491 session_clear_tty(tty->session);
2498 /* See the comment in tty_open(). */
2499 if ((file->f_mode & FMODE_READ) == 0 && !capable(CAP_SYS_ADMIN)) {
2506 read_unlock(&tasklist_lock);
2512 * tty_get_pgrp - return a ref counted pgrp pid
2515 * Returns a refcounted instance of the pid struct for the process
2516 * group controlling the tty.
2519 struct pid *tty_get_pgrp(struct tty_struct *tty)
2521 unsigned long flags;
2524 spin_lock_irqsave(&tty->ctrl_lock, flags);
2525 pgrp = get_pid(tty->pgrp);
2526 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2530 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2533 * This checks not only the pgrp, but falls back on the pid if no
2534 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
2537 * The caller must hold rcu lock or the tasklist lock.
2539 static struct pid *session_of_pgrp(struct pid *pgrp)
2541 struct task_struct *p;
2542 struct pid *sid = NULL;
2544 p = pid_task(pgrp, PIDTYPE_PGID);
2546 p = pid_task(pgrp, PIDTYPE_PID);
2548 sid = task_session(p);
2554 * tiocgpgrp - get process group
2555 * @tty: tty passed by user
2556 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2559 * Obtain the process group of the tty. If there is no process group
2562 * Locking: none. Reference to current->signal->tty is safe.
2565 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2570 * (tty == real_tty) is a cheap way of
2571 * testing if the tty is NOT a master pty.
2573 if (tty == real_tty && current->signal->tty != real_tty)
2575 pid = tty_get_pgrp(real_tty);
2576 ret = put_user(pid_vnr(pid), p);
2582 * tiocspgrp - attempt to set process group
2583 * @tty: tty passed by user
2584 * @real_tty: tty side device matching tty passed by user
2587 * Set the process group of the tty to the session passed. Only
2588 * permitted where the tty session is our session.
2590 * Locking: RCU, ctrl lock
2593 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2597 int retval = tty_check_change(real_tty);
2603 if (!current->signal->tty ||
2604 (current->signal->tty != real_tty) ||
2605 (real_tty->session != task_session(current)))
2607 if (get_user(pgrp_nr, p))
2612 pgrp = find_vpid(pgrp_nr);
2617 if (session_of_pgrp(pgrp) != task_session(current))
2620 spin_lock_irq(&tty->ctrl_lock);
2621 put_pid(real_tty->pgrp);
2622 real_tty->pgrp = get_pid(pgrp);
2623 spin_unlock_irq(&tty->ctrl_lock);
2630 * tiocgsid - get session id
2631 * @tty: tty passed by user
2632 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2633 * @p: pointer to returned session id
2635 * Obtain the session id of the tty. If there is no session
2638 * Locking: none. Reference to current->signal->tty is safe.
2641 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2644 * (tty == real_tty) is a cheap way of
2645 * testing if the tty is NOT a master pty.
2647 if (tty == real_tty && current->signal->tty != real_tty)
2649 if (!real_tty->session)
2651 return put_user(pid_vnr(real_tty->session), p);
2655 * tiocsetd - set line discipline
2657 * @p: pointer to user data
2659 * Set the line discipline according to user request.
2661 * Locking: see tty_set_ldisc, this function is just a helper
2664 static int tiocsetd(struct tty_struct *tty, int __user *p)
2669 if (get_user(disc, p))
2672 ret = tty_set_ldisc(tty, disc);
2678 * tiocgetd - get line discipline
2680 * @p: pointer to user data
2682 * Retrieves the line discipline id directly from the ldisc.
2684 * Locking: waits for ldisc reference (in case the line discipline
2685 * is changing or the tty is being hungup)
2688 static int tiocgetd(struct tty_struct *tty, int __user *p)
2690 struct tty_ldisc *ld;
2693 ld = tty_ldisc_ref_wait(tty);
2696 ret = put_user(ld->ops->num, p);
2697 tty_ldisc_deref(ld);
2702 * send_break - performed time break
2703 * @tty: device to break on
2704 * @duration: timeout in mS
2706 * Perform a timed break on hardware that lacks its own driver level
2707 * timed break functionality.
2710 * atomic_write_lock serializes
2714 static int send_break(struct tty_struct *tty, unsigned int duration)
2718 if (tty->ops->break_ctl == NULL)
2721 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2722 retval = tty->ops->break_ctl(tty, duration);
2724 /* Do the work ourselves */
2725 if (tty_write_lock(tty, 0) < 0)
2727 retval = tty->ops->break_ctl(tty, -1);
2730 if (!signal_pending(current))
2731 msleep_interruptible(duration);
2732 retval = tty->ops->break_ctl(tty, 0);
2734 tty_write_unlock(tty);
2735 if (signal_pending(current))
2742 * tty_tiocmget - get modem status
2744 * @file: user file pointer
2745 * @p: pointer to result
2747 * Obtain the modem status bits from the tty driver if the feature
2748 * is supported. Return -EINVAL if it is not available.
2750 * Locking: none (up to the driver)
2753 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2755 int retval = -EINVAL;
2757 if (tty->ops->tiocmget) {
2758 retval = tty->ops->tiocmget(tty);
2761 retval = put_user(retval, p);
2767 * tty_tiocmset - set modem status
2769 * @cmd: command - clear bits, set bits or set all
2770 * @p: pointer to desired bits
2772 * Set the modem status bits from the tty driver if the feature
2773 * is supported. Return -EINVAL if it is not available.
2775 * Locking: none (up to the driver)
2778 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2782 unsigned int set, clear, val;
2784 if (tty->ops->tiocmset == NULL)
2787 retval = get_user(val, p);
2803 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2804 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2805 return tty->ops->tiocmset(tty, set, clear);
2808 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2810 int retval = -EINVAL;
2811 struct serial_icounter_struct icount;
2812 memset(&icount, 0, sizeof(icount));
2813 if (tty->ops->get_icount)
2814 retval = tty->ops->get_icount(tty, &icount);
2817 if (copy_to_user(arg, &icount, sizeof(icount)))
2822 static void tty_warn_deprecated_flags(struct serial_struct __user *ss)
2824 static DEFINE_RATELIMIT_STATE(depr_flags,
2825 DEFAULT_RATELIMIT_INTERVAL,
2826 DEFAULT_RATELIMIT_BURST);
2827 char comm[TASK_COMM_LEN];
2830 if (get_user(flags, &ss->flags))
2833 flags &= ASYNC_DEPRECATED;
2835 if (flags && __ratelimit(&depr_flags))
2836 pr_warning("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2837 __func__, get_task_comm(comm, current), flags);
2841 * if pty, return the slave side (real_tty)
2842 * otherwise, return self
2844 static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2846 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2847 tty->driver->subtype == PTY_TYPE_MASTER)
2853 * Split this up, as gcc can choke on it otherwise..
2855 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2857 struct tty_struct *tty = file_tty(file);
2858 struct tty_struct *real_tty;
2859 void __user *p = (void __user *)arg;
2861 struct tty_ldisc *ld;
2863 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2866 real_tty = tty_pair_get_tty(tty);
2869 * Factor out some common prep work
2877 retval = tty_check_change(tty);
2880 if (cmd != TIOCCBRK) {
2881 tty_wait_until_sent(tty, 0);
2882 if (signal_pending(current))
2893 return tiocsti(tty, p);
2895 return tiocgwinsz(real_tty, p);
2897 return tiocswinsz(real_tty, p);
2899 return real_tty != tty ? -EINVAL : tioccons(file);
2901 return fionbio(file, p);
2903 set_bit(TTY_EXCLUSIVE, &tty->flags);
2906 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2910 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2911 return put_user(excl, (int __user *)p);
2914 if (current->signal->tty != tty)
2919 return tiocsctty(real_tty, file, arg);
2921 return tiocgpgrp(tty, real_tty, p);
2923 return tiocspgrp(tty, real_tty, p);
2925 return tiocgsid(tty, real_tty, p);
2927 return tiocgetd(tty, p);
2929 return tiocsetd(tty, p);
2931 if (!capable(CAP_SYS_ADMIN))
2937 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2938 return put_user(ret, (unsigned int __user *)p);
2943 case TIOCSBRK: /* Turn break on, unconditionally */
2944 if (tty->ops->break_ctl)
2945 return tty->ops->break_ctl(tty, -1);
2947 case TIOCCBRK: /* Turn break off, unconditionally */
2948 if (tty->ops->break_ctl)
2949 return tty->ops->break_ctl(tty, 0);
2951 case TCSBRK: /* SVID version: non-zero arg --> no break */
2952 /* non-zero arg means wait for all output data
2953 * to be sent (performed above) but don't send break.
2954 * This is used by the tcdrain() termios function.
2957 return send_break(tty, 250);
2959 case TCSBRKP: /* support for POSIX tcsendbreak() */
2960 return send_break(tty, arg ? arg*100 : 250);
2963 return tty_tiocmget(tty, p);
2967 return tty_tiocmset(tty, cmd, p);
2969 retval = tty_tiocgicount(tty, p);
2970 /* For the moment allow fall through to the old method */
2971 if (retval != -EINVAL)
2978 /* flush tty buffer and allow ldisc to process ioctl */
2979 tty_buffer_flush(tty, NULL);
2984 tty_warn_deprecated_flags(p);
2987 if (tty->ops->ioctl) {
2988 retval = tty->ops->ioctl(tty, cmd, arg);
2989 if (retval != -ENOIOCTLCMD)
2992 ld = tty_ldisc_ref_wait(tty);
2994 return hung_up_tty_ioctl(file, cmd, arg);
2996 if (ld->ops->ioctl) {
2997 retval = ld->ops->ioctl(tty, file, cmd, arg);
2998 if (retval == -ENOIOCTLCMD)
3001 tty_ldisc_deref(ld);
3005 #ifdef CONFIG_COMPAT
3006 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
3009 struct tty_struct *tty = file_tty(file);
3010 struct tty_ldisc *ld;
3011 int retval = -ENOIOCTLCMD;
3013 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
3016 if (tty->ops->compat_ioctl) {
3017 retval = tty->ops->compat_ioctl(tty, cmd, arg);
3018 if (retval != -ENOIOCTLCMD)
3022 ld = tty_ldisc_ref_wait(tty);
3024 return hung_up_tty_compat_ioctl(file, cmd, arg);
3025 if (ld->ops->compat_ioctl)
3026 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
3028 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
3029 tty_ldisc_deref(ld);
3035 static int this_tty(const void *t, struct file *file, unsigned fd)
3037 if (likely(file->f_op->read != tty_read))
3039 return file_tty(file) != t ? 0 : fd + 1;
3043 * This implements the "Secure Attention Key" --- the idea is to
3044 * prevent trojan horses by killing all processes associated with this
3045 * tty when the user hits the "Secure Attention Key". Required for
3046 * super-paranoid applications --- see the Orange Book for more details.
3048 * This code could be nicer; ideally it should send a HUP, wait a few
3049 * seconds, then send a INT, and then a KILL signal. But you then
3050 * have to coordinate with the init process, since all processes associated
3051 * with the current tty must be dead before the new getty is allowed
3054 * Now, if it would be correct ;-/ The current code has a nasty hole -
3055 * it doesn't catch files in flight. We may send the descriptor to ourselves
3056 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
3058 * Nasty bug: do_SAK is being called in interrupt context. This can
3059 * deadlock. We punt it up to process context. AKPM - 16Mar2001
3061 void __do_SAK(struct tty_struct *tty)
3066 struct task_struct *g, *p;
3067 struct pid *session;
3072 session = tty->session;
3074 tty_ldisc_flush(tty);
3076 tty_driver_flush_buffer(tty);
3078 read_lock(&tasklist_lock);
3079 /* Kill the entire session */
3080 do_each_pid_task(session, PIDTYPE_SID, p) {
3081 tty_notice(tty, "SAK: killed process %d (%s): by session\n",
3082 task_pid_nr(p), p->comm);
3083 send_sig(SIGKILL, p, 1);
3084 } while_each_pid_task(session, PIDTYPE_SID, p);
3086 /* Now kill any processes that happen to have the tty open */
3087 do_each_thread(g, p) {
3088 if (p->signal->tty == tty) {
3089 tty_notice(tty, "SAK: killed process %d (%s): by controlling tty\n",
3090 task_pid_nr(p), p->comm);
3091 send_sig(SIGKILL, p, 1);
3095 i = iterate_fd(p->files, 0, this_tty, tty);
3097 tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n",
3098 task_pid_nr(p), p->comm, i - 1);
3099 force_sig(SIGKILL, p);
3102 } while_each_thread(g, p);
3103 read_unlock(&tasklist_lock);
3107 static void do_SAK_work(struct work_struct *work)
3109 struct tty_struct *tty =
3110 container_of(work, struct tty_struct, SAK_work);
3115 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3116 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3117 * the values which we write to it will be identical to the values which it
3118 * already has. --akpm
3120 void do_SAK(struct tty_struct *tty)
3124 schedule_work(&tty->SAK_work);
3127 EXPORT_SYMBOL(do_SAK);
3129 static int dev_match_devt(struct device *dev, const void *data)
3131 const dev_t *devt = data;
3132 return dev->devt == *devt;
3135 /* Must put_device() after it's unused! */
3136 static struct device *tty_get_device(struct tty_struct *tty)
3138 dev_t devt = tty_devnum(tty);
3139 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
3146 * This subroutine allocates and initializes a tty structure.
3148 * Locking: none - tty in question is not exposed at this point
3151 struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
3153 struct tty_struct *tty;
3155 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
3159 kref_init(&tty->kref);
3160 tty->magic = TTY_MAGIC;
3161 tty_ldisc_init(tty);
3162 tty->session = NULL;
3164 mutex_init(&tty->legacy_mutex);
3165 mutex_init(&tty->throttle_mutex);
3166 init_rwsem(&tty->termios_rwsem);
3167 mutex_init(&tty->winsize_mutex);
3168 init_ldsem(&tty->ldisc_sem);
3169 init_waitqueue_head(&tty->write_wait);
3170 init_waitqueue_head(&tty->read_wait);
3171 INIT_WORK(&tty->hangup_work, do_tty_hangup);
3172 mutex_init(&tty->atomic_write_lock);
3173 spin_lock_init(&tty->ctrl_lock);
3174 spin_lock_init(&tty->flow_lock);
3175 INIT_LIST_HEAD(&tty->tty_files);
3176 INIT_WORK(&tty->SAK_work, do_SAK_work);
3178 tty->driver = driver;
3179 tty->ops = driver->ops;
3181 tty_line_name(driver, idx, tty->name);
3182 tty->dev = tty_get_device(tty);
3188 * tty_put_char - write one character to a tty
3192 * Write one byte to the tty using the provided put_char method
3193 * if present. Returns the number of characters successfully output.
3195 * Note: the specific put_char operation in the driver layer may go
3196 * away soon. Don't call it directly, use this method
3199 int tty_put_char(struct tty_struct *tty, unsigned char ch)
3201 if (tty->ops->put_char)
3202 return tty->ops->put_char(tty, ch);
3203 return tty->ops->write(tty, &ch, 1);
3205 EXPORT_SYMBOL_GPL(tty_put_char);
3207 struct class *tty_class;
3209 static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3210 unsigned int index, unsigned int count)
3214 /* init here, since reused cdevs cause crashes */
3215 driver->cdevs[index] = cdev_alloc();
3216 if (!driver->cdevs[index])
3218 driver->cdevs[index]->ops = &tty_fops;
3219 driver->cdevs[index]->owner = driver->owner;
3220 err = cdev_add(driver->cdevs[index], dev, count);
3222 kobject_put(&driver->cdevs[index]->kobj);
3227 * tty_register_device - register a tty device
3228 * @driver: the tty driver that describes the tty device
3229 * @index: the index in the tty driver for this tty device
3230 * @device: a struct device that is associated with this tty device.
3231 * This field is optional, if there is no known struct device
3232 * for this tty device it can be set to NULL safely.
3234 * Returns a pointer to the struct device for this tty device
3235 * (or ERR_PTR(-EFOO) on error).
3237 * This call is required to be made to register an individual tty device
3238 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3239 * that bit is not set, this function should not be called by a tty
3245 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3246 struct device *device)
3248 return tty_register_device_attr(driver, index, device, NULL, NULL);
3250 EXPORT_SYMBOL(tty_register_device);
3252 static void tty_device_create_release(struct device *dev)
3254 dev_dbg(dev, "releasing...\n");
3259 * tty_register_device_attr - register a tty device
3260 * @driver: the tty driver that describes the tty device
3261 * @index: the index in the tty driver for this tty device
3262 * @device: a struct device that is associated with this tty device.
3263 * This field is optional, if there is no known struct device
3264 * for this tty device it can be set to NULL safely.
3265 * @drvdata: Driver data to be set to device.
3266 * @attr_grp: Attribute group to be set on device.
3268 * Returns a pointer to the struct device for this tty device
3269 * (or ERR_PTR(-EFOO) on error).
3271 * This call is required to be made to register an individual tty device
3272 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3273 * that bit is not set, this function should not be called by a tty
3278 struct device *tty_register_device_attr(struct tty_driver *driver,
3279 unsigned index, struct device *device,
3281 const struct attribute_group **attr_grp)
3284 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3285 struct device *dev = NULL;
3286 int retval = -ENODEV;
3289 if (index >= driver->num) {
3290 pr_err("%s: Attempt to register invalid tty line number (%d)\n",
3291 driver->name, index);
3292 return ERR_PTR(-EINVAL);
3295 if (driver->type == TTY_DRIVER_TYPE_PTY)
3296 pty_line_name(driver, index, name);
3298 tty_line_name(driver, index, name);
3300 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3301 retval = tty_cdev_add(driver, devt, index, 1);
3307 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3314 dev->class = tty_class;
3315 dev->parent = device;
3316 dev->release = tty_device_create_release;
3317 dev_set_name(dev, "%s", name);
3318 dev->groups = attr_grp;
3319 dev_set_drvdata(dev, drvdata);
3321 retval = device_register(dev);
3330 cdev_del(driver->cdevs[index]);
3331 driver->cdevs[index] = NULL;
3333 return ERR_PTR(retval);
3335 EXPORT_SYMBOL_GPL(tty_register_device_attr);
3338 * tty_unregister_device - unregister a tty device
3339 * @driver: the tty driver that describes the tty device
3340 * @index: the index in the tty driver for this tty device
3342 * If a tty device is registered with a call to tty_register_device() then
3343 * this function must be called when the tty device is gone.
3348 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3350 device_destroy(tty_class,
3351 MKDEV(driver->major, driver->minor_start) + index);
3352 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3353 cdev_del(driver->cdevs[index]);
3354 driver->cdevs[index] = NULL;
3357 EXPORT_SYMBOL(tty_unregister_device);
3360 * __tty_alloc_driver -- allocate tty driver
3361 * @lines: count of lines this driver can handle at most
3362 * @owner: module which is repsonsible for this driver
3363 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3365 * This should not be called directly, some of the provided macros should be
3366 * used instead. Use IS_ERR and friends on @retval.
3368 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3369 unsigned long flags)
3371 struct tty_driver *driver;
3372 unsigned int cdevs = 1;
3375 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3376 return ERR_PTR(-EINVAL);
3378 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3380 return ERR_PTR(-ENOMEM);
3382 kref_init(&driver->kref);
3383 driver->magic = TTY_DRIVER_MAGIC;
3384 driver->num = lines;
3385 driver->owner = owner;
3386 driver->flags = flags;
3388 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3389 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3391 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3393 if (!driver->ttys || !driver->termios) {
3399 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3400 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3402 if (!driver->ports) {
3409 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3410 if (!driver->cdevs) {
3417 kfree(driver->ports);
3418 kfree(driver->ttys);
3419 kfree(driver->termios);
3420 kfree(driver->cdevs);
3422 return ERR_PTR(err);
3424 EXPORT_SYMBOL(__tty_alloc_driver);
3426 static void destruct_tty_driver(struct kref *kref)
3428 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3430 struct ktermios *tp;
3432 if (driver->flags & TTY_DRIVER_INSTALLED) {
3434 * Free the termios and termios_locked structures because
3435 * we don't want to get memory leaks when modular tty
3436 * drivers are removed from the kernel.
3438 for (i = 0; i < driver->num; i++) {
3439 tp = driver->termios[i];
3441 driver->termios[i] = NULL;
3444 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3445 tty_unregister_device(driver, i);
3447 proc_tty_unregister_driver(driver);
3448 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3449 cdev_del(driver->cdevs[0]);
3451 kfree(driver->cdevs);
3452 kfree(driver->ports);
3453 kfree(driver->termios);
3454 kfree(driver->ttys);
3458 void tty_driver_kref_put(struct tty_driver *driver)
3460 kref_put(&driver->kref, destruct_tty_driver);
3462 EXPORT_SYMBOL(tty_driver_kref_put);
3464 void tty_set_operations(struct tty_driver *driver,
3465 const struct tty_operations *op)
3469 EXPORT_SYMBOL(tty_set_operations);
3471 void put_tty_driver(struct tty_driver *d)
3473 tty_driver_kref_put(d);
3475 EXPORT_SYMBOL(put_tty_driver);
3478 * Called by a tty driver to register itself.
3480 int tty_register_driver(struct tty_driver *driver)
3487 if (!driver->major) {
3488 error = alloc_chrdev_region(&dev, driver->minor_start,
3489 driver->num, driver->name);
3491 driver->major = MAJOR(dev);
3492 driver->minor_start = MINOR(dev);
3495 dev = MKDEV(driver->major, driver->minor_start);
3496 error = register_chrdev_region(dev, driver->num, driver->name);
3501 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3502 error = tty_cdev_add(driver, dev, 0, driver->num);
3504 goto err_unreg_char;
3507 mutex_lock(&tty_mutex);
3508 list_add(&driver->tty_drivers, &tty_drivers);
3509 mutex_unlock(&tty_mutex);
3511 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3512 for (i = 0; i < driver->num; i++) {
3513 d = tty_register_device(driver, i, NULL);
3516 goto err_unreg_devs;
3520 proc_tty_register_driver(driver);
3521 driver->flags |= TTY_DRIVER_INSTALLED;
3525 for (i--; i >= 0; i--)
3526 tty_unregister_device(driver, i);
3528 mutex_lock(&tty_mutex);
3529 list_del(&driver->tty_drivers);
3530 mutex_unlock(&tty_mutex);
3533 unregister_chrdev_region(dev, driver->num);
3537 EXPORT_SYMBOL(tty_register_driver);
3540 * Called by a tty driver to unregister itself.
3542 int tty_unregister_driver(struct tty_driver *driver)
3546 if (driver->refcount)
3549 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3551 mutex_lock(&tty_mutex);
3552 list_del(&driver->tty_drivers);
3553 mutex_unlock(&tty_mutex);
3557 EXPORT_SYMBOL(tty_unregister_driver);
3559 dev_t tty_devnum(struct tty_struct *tty)
3561 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3563 EXPORT_SYMBOL(tty_devnum);
3565 void tty_default_fops(struct file_operations *fops)
3571 * Initialize the console device. This is called *early*, so
3572 * we can't necessarily depend on lots of kernel help here.
3573 * Just do some early initializations, and do the complex setup
3576 void __init console_init(void)
3580 /* Setup the default TTY line discipline. */
3584 * set up the console device so that later boot sequences can
3585 * inform about problems etc..
3587 call = __con_initcall_start;
3588 while (call < __con_initcall_end) {
3594 static char *tty_devnode(struct device *dev, umode_t *mode)
3598 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3599 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3604 static int __init tty_class_init(void)
3606 tty_class = class_create(THIS_MODULE, "tty");
3607 if (IS_ERR(tty_class))
3608 return PTR_ERR(tty_class);
3609 tty_class->devnode = tty_devnode;
3613 postcore_initcall(tty_class_init);
3615 /* 3/2004 jmc: why do these devices exist? */
3616 static struct cdev tty_cdev, console_cdev;
3618 static ssize_t show_cons_active(struct device *dev,
3619 struct device_attribute *attr, char *buf)
3621 struct console *cs[16];
3627 for_each_console(c) {
3632 if ((c->flags & CON_ENABLED) == 0)
3635 if (i >= ARRAY_SIZE(cs))
3639 int index = cs[i]->index;
3640 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3642 /* don't resolve tty0 as some programs depend on it */
3643 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3644 count += tty_line_name(drv, index, buf + count);
3646 count += sprintf(buf + count, "%s%d",
3647 cs[i]->name, cs[i]->index);
3649 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3655 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3657 static struct attribute *cons_dev_attrs[] = {
3658 &dev_attr_active.attr,
3662 ATTRIBUTE_GROUPS(cons_dev);
3664 static struct device *consdev;
3666 void console_sysfs_notify(void)
3669 sysfs_notify(&consdev->kobj, NULL, "active");
3673 * Ok, now we can initialize the rest of the tty devices and can count
3674 * on memory allocations, interrupts etc..
3676 int __init tty_init(void)
3678 cdev_init(&tty_cdev, &tty_fops);
3679 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3680 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3681 panic("Couldn't register /dev/tty driver\n");
3682 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3684 cdev_init(&console_cdev, &console_fops);
3685 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3686 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3687 panic("Couldn't register /dev/console driver\n");
3688 consdev = device_create_with_groups(tty_class, NULL,
3689 MKDEV(TTYAUX_MAJOR, 1), NULL,
3690 cons_dev_groups, "console");
3691 if (IS_ERR(consdev))
3695 vty_init(&console_fops);