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
110 #define TTY_PARANOIA_CHECK 1
111 #define CHECK_TTY_COUNT 1
113 struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
114 .c_iflag = ICRNL | IXON,
115 .c_oflag = OPOST | ONLCR,
116 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
117 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
118 ECHOCTL | ECHOKE | IEXTEN,
124 EXPORT_SYMBOL(tty_std_termios);
126 /* This list gets poked at by procfs and various bits of boot up code. This
127 could do with some rationalisation such as pulling the tty proc function
130 LIST_HEAD(tty_drivers); /* linked list of tty drivers */
132 /* Mutex to protect creating and releasing a tty. This is shared with
133 vt.c for deeply disgusting hack reasons */
134 DEFINE_MUTEX(tty_mutex);
135 EXPORT_SYMBOL(tty_mutex);
137 /* Spinlock to protect the tty->tty_files list */
138 DEFINE_SPINLOCK(tty_files_lock);
140 static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
141 static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
142 ssize_t redirected_tty_write(struct file *, const char __user *,
144 static unsigned int tty_poll(struct file *, poll_table *);
145 static int tty_open(struct inode *, struct file *);
146 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
148 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
151 #define tty_compat_ioctl NULL
153 static int __tty_fasync(int fd, struct file *filp, int on);
154 static int tty_fasync(int fd, struct file *filp, int on);
155 static void release_tty(struct tty_struct *tty, int idx);
158 * free_tty_struct - free a disused tty
159 * @tty: tty struct to free
161 * Free the write buffers, tty queue and tty memory itself.
163 * Locking: none. Must be called after tty is definitely unused
166 void free_tty_struct(struct tty_struct *tty)
170 put_device(tty->dev);
171 kfree(tty->write_buf);
172 tty->magic = 0xDEADDEAD;
176 static inline struct tty_struct *file_tty(struct file *file)
178 return ((struct tty_file_private *)file->private_data)->tty;
181 int tty_alloc_file(struct file *file)
183 struct tty_file_private *priv;
185 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
189 file->private_data = priv;
194 /* Associate a new file with the tty structure */
195 void tty_add_file(struct tty_struct *tty, struct file *file)
197 struct tty_file_private *priv = file->private_data;
202 spin_lock(&tty_files_lock);
203 list_add(&priv->list, &tty->tty_files);
204 spin_unlock(&tty_files_lock);
208 * tty_free_file - free file->private_data
210 * This shall be used only for fail path handling when tty_add_file was not
213 void tty_free_file(struct file *file)
215 struct tty_file_private *priv = file->private_data;
217 file->private_data = NULL;
221 /* Delete file from its tty */
222 static void tty_del_file(struct file *file)
224 struct tty_file_private *priv = file->private_data;
226 spin_lock(&tty_files_lock);
227 list_del(&priv->list);
228 spin_unlock(&tty_files_lock);
233 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
236 * tty_name - return tty naming
237 * @tty: tty structure
239 * Convert a tty structure into a name. The name reflects the kernel
240 * naming policy and if udev is in use may not reflect user space
245 const char *tty_name(const struct tty_struct *tty)
247 if (!tty) /* Hmm. NULL pointer. That's fun. */
252 EXPORT_SYMBOL(tty_name);
254 int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
257 #ifdef TTY_PARANOIA_CHECK
260 "null TTY for (%d:%d) in %s\n",
261 imajor(inode), iminor(inode), routine);
264 if (tty->magic != TTY_MAGIC) {
266 "bad magic number for tty struct (%d:%d) in %s\n",
267 imajor(inode), iminor(inode), routine);
274 /* Caller must hold tty_lock */
275 static int check_tty_count(struct tty_struct *tty, const char *routine)
277 #ifdef CHECK_TTY_COUNT
281 spin_lock(&tty_files_lock);
282 list_for_each(p, &tty->tty_files) {
285 spin_unlock(&tty_files_lock);
286 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
287 tty->driver->subtype == PTY_TYPE_SLAVE &&
288 tty->link && tty->link->count)
290 if (tty->count != count) {
291 printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) "
292 "!= #fd's(%d) in %s\n",
293 tty->name, tty->count, count, routine);
301 * get_tty_driver - find device of a tty
302 * @dev_t: device identifier
303 * @index: returns the index of the tty
305 * This routine returns a tty driver structure, given a device number
306 * and also passes back the index number.
308 * Locking: caller must hold tty_mutex
311 static struct tty_driver *get_tty_driver(dev_t device, int *index)
313 struct tty_driver *p;
315 list_for_each_entry(p, &tty_drivers, tty_drivers) {
316 dev_t base = MKDEV(p->major, p->minor_start);
317 if (device < base || device >= base + p->num)
319 *index = device - base;
320 return tty_driver_kref_get(p);
325 #ifdef CONFIG_CONSOLE_POLL
328 * tty_find_polling_driver - find device of a polled tty
329 * @name: name string to match
330 * @line: pointer to resulting tty line nr
332 * This routine returns a tty driver structure, given a name
333 * and the condition that the tty driver is capable of polled
336 struct tty_driver *tty_find_polling_driver(char *name, int *line)
338 struct tty_driver *p, *res = NULL;
343 for (str = name; *str; str++)
344 if ((*str >= '0' && *str <= '9') || *str == ',')
350 tty_line = simple_strtoul(str, &str, 10);
352 mutex_lock(&tty_mutex);
353 /* Search through the tty devices to look for a match */
354 list_for_each_entry(p, &tty_drivers, tty_drivers) {
355 if (strncmp(name, p->name, len) != 0)
363 if (tty_line >= 0 && tty_line < p->num && p->ops &&
364 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
365 res = tty_driver_kref_get(p);
370 mutex_unlock(&tty_mutex);
374 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
378 * tty_check_change - check for POSIX terminal changes
381 * If we try to write to, or set the state of, a terminal and we're
382 * not in the foreground, send a SIGTTOU. If the signal is blocked or
383 * ignored, go ahead and perform the operation. (POSIX 7.2)
388 int tty_check_change(struct tty_struct *tty)
393 if (current->signal->tty != tty)
396 spin_lock_irqsave(&tty->ctrl_lock, flags);
399 printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
402 if (task_pgrp(current) == tty->pgrp)
404 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
405 if (is_ignored(SIGTTOU))
407 if (is_current_pgrp_orphaned()) {
411 kill_pgrp(task_pgrp(current), SIGTTOU, 1);
412 set_thread_flag(TIF_SIGPENDING);
417 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
421 EXPORT_SYMBOL(tty_check_change);
423 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
424 size_t count, loff_t *ppos)
429 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
430 size_t count, loff_t *ppos)
435 /* No kernel lock held - none needed ;) */
436 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
438 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
441 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
444 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
447 static long hung_up_tty_compat_ioctl(struct file *file,
448 unsigned int cmd, unsigned long arg)
450 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
453 static const struct file_operations tty_fops = {
458 .unlocked_ioctl = tty_ioctl,
459 .compat_ioctl = tty_compat_ioctl,
461 .release = tty_release,
462 .fasync = tty_fasync,
465 static const struct file_operations console_fops = {
468 .write = redirected_tty_write,
470 .unlocked_ioctl = tty_ioctl,
471 .compat_ioctl = tty_compat_ioctl,
473 .release = tty_release,
474 .fasync = tty_fasync,
477 static const struct file_operations hung_up_tty_fops = {
479 .read = hung_up_tty_read,
480 .write = hung_up_tty_write,
481 .poll = hung_up_tty_poll,
482 .unlocked_ioctl = hung_up_tty_ioctl,
483 .compat_ioctl = hung_up_tty_compat_ioctl,
484 .release = tty_release,
487 static DEFINE_SPINLOCK(redirect_lock);
488 static struct file *redirect;
491 void proc_clear_tty(struct task_struct *p)
494 struct tty_struct *tty;
495 spin_lock_irqsave(&p->sighand->siglock, flags);
496 tty = p->signal->tty;
497 p->signal->tty = NULL;
498 spin_unlock_irqrestore(&p->sighand->siglock, flags);
503 * proc_set_tty - set the controlling terminal
505 * Only callable by the session leader and only if it does not already have
506 * a controlling terminal.
508 * Caller must hold: tty_lock()
509 * a readlock on tasklist_lock
512 static void __proc_set_tty(struct tty_struct *tty)
516 spin_lock_irqsave(&tty->ctrl_lock, flags);
518 * The session and fg pgrp references will be non-NULL if
519 * tiocsctty() is stealing the controlling tty
521 put_pid(tty->session);
523 tty->pgrp = get_pid(task_pgrp(current));
524 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
525 tty->session = get_pid(task_session(current));
526 if (current->signal->tty) {
527 printk(KERN_DEBUG "tty not NULL!!\n");
528 tty_kref_put(current->signal->tty);
530 put_pid(current->signal->tty_old_pgrp);
531 current->signal->tty = tty_kref_get(tty);
532 current->signal->tty_old_pgrp = NULL;
535 static void proc_set_tty(struct tty_struct *tty)
537 spin_lock_irq(¤t->sighand->siglock);
539 spin_unlock_irq(¤t->sighand->siglock);
542 struct tty_struct *get_current_tty(void)
544 struct tty_struct *tty;
547 spin_lock_irqsave(¤t->sighand->siglock, flags);
548 tty = tty_kref_get(current->signal->tty);
549 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
552 EXPORT_SYMBOL_GPL(get_current_tty);
554 static void session_clear_tty(struct pid *session)
556 struct task_struct *p;
557 do_each_pid_task(session, PIDTYPE_SID, p) {
559 } while_each_pid_task(session, PIDTYPE_SID, p);
563 * tty_wakeup - request more data
566 * Internal and external helper for wakeups of tty. This function
567 * informs the line discipline if present that the driver is ready
568 * to receive more output data.
571 void tty_wakeup(struct tty_struct *tty)
573 struct tty_ldisc *ld;
575 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
576 ld = tty_ldisc_ref(tty);
578 if (ld->ops->write_wakeup)
579 ld->ops->write_wakeup(tty);
583 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
586 EXPORT_SYMBOL_GPL(tty_wakeup);
589 * tty_signal_session_leader - sends SIGHUP to session leader
590 * @tty controlling tty
591 * @exit_session if non-zero, signal all foreground group processes
593 * Send SIGHUP and SIGCONT to the session leader and its process group.
594 * Optionally, signal all processes in the foreground process group.
596 * Returns the number of processes in the session with this tty
597 * as their controlling terminal. This value is used to drop
598 * tty references for those processes.
600 static int tty_signal_session_leader(struct tty_struct *tty, int exit_session)
602 struct task_struct *p;
604 struct pid *tty_pgrp = NULL;
606 read_lock(&tasklist_lock);
608 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
609 spin_lock_irq(&p->sighand->siglock);
610 if (p->signal->tty == tty) {
611 p->signal->tty = NULL;
612 /* We defer the dereferences outside fo
616 if (!p->signal->leader) {
617 spin_unlock_irq(&p->sighand->siglock);
620 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
621 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
622 put_pid(p->signal->tty_old_pgrp); /* A noop */
623 spin_lock(&tty->ctrl_lock);
624 tty_pgrp = get_pid(tty->pgrp);
626 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
627 spin_unlock(&tty->ctrl_lock);
628 spin_unlock_irq(&p->sighand->siglock);
629 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
631 read_unlock(&tasklist_lock);
635 kill_pgrp(tty_pgrp, SIGHUP, exit_session);
643 * __tty_hangup - actual handler for hangup events
646 * This can be called by a "kworker" kernel thread. That is process
647 * synchronous but doesn't hold any locks, so we need to make sure we
648 * have the appropriate locks for what we're doing.
650 * The hangup event clears any pending redirections onto the hung up
651 * device. It ensures future writes will error and it does the needed
652 * line discipline hangup and signal delivery. The tty object itself
657 * redirect lock for undoing redirection
658 * file list lock for manipulating list of ttys
659 * tty_ldiscs_lock from called functions
660 * termios_rwsem resetting termios data
661 * tasklist_lock to walk task list for hangup event
662 * ->siglock to protect ->signal/->sighand
664 static void __tty_hangup(struct tty_struct *tty, int exit_session)
666 struct file *cons_filp = NULL;
667 struct file *filp, *f = NULL;
668 struct tty_file_private *priv;
669 int closecount = 0, n;
676 spin_lock(&redirect_lock);
677 if (redirect && file_tty(redirect) == tty) {
681 spin_unlock(&redirect_lock);
685 if (test_bit(TTY_HUPPED, &tty->flags)) {
690 /* inuse_filps is protected by the single tty lock,
691 this really needs to change if we want to flush the
692 workqueue with the lock held */
693 check_tty_count(tty, "tty_hangup");
695 spin_lock(&tty_files_lock);
696 /* This breaks for file handles being sent over AF_UNIX sockets ? */
697 list_for_each_entry(priv, &tty->tty_files, list) {
699 if (filp->f_op->write == redirected_tty_write)
701 if (filp->f_op->write != tty_write)
704 __tty_fasync(-1, filp, 0); /* can't block */
705 filp->f_op = &hung_up_tty_fops;
707 spin_unlock(&tty_files_lock);
709 refs = tty_signal_session_leader(tty, exit_session);
710 /* Account for the p->signal references we killed */
714 tty_ldisc_hangup(tty);
716 spin_lock_irq(&tty->ctrl_lock);
717 clear_bit(TTY_THROTTLED, &tty->flags);
718 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
719 put_pid(tty->session);
723 tty->ctrl_status = 0;
724 spin_unlock_irq(&tty->ctrl_lock);
727 * If one of the devices matches a console pointer, we
728 * cannot just call hangup() because that will cause
729 * tty->count and state->count to go out of sync.
730 * So we just call close() the right number of times.
734 for (n = 0; n < closecount; n++)
735 tty->ops->close(tty, cons_filp);
736 } else if (tty->ops->hangup)
737 tty->ops->hangup(tty);
739 * We don't want to have driver/ldisc interactions beyond
740 * the ones we did here. The driver layer expects no
741 * calls after ->hangup() from the ldisc side. However we
742 * can't yet guarantee all that.
744 set_bit(TTY_HUPPED, &tty->flags);
751 static void do_tty_hangup(struct work_struct *work)
753 struct tty_struct *tty =
754 container_of(work, struct tty_struct, hangup_work);
756 __tty_hangup(tty, 0);
760 * tty_hangup - trigger a hangup event
761 * @tty: tty to hangup
763 * A carrier loss (virtual or otherwise) has occurred on this like
764 * schedule a hangup sequence to run after this event.
767 void tty_hangup(struct tty_struct *tty)
769 #ifdef TTY_DEBUG_HANGUP
770 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty));
772 schedule_work(&tty->hangup_work);
775 EXPORT_SYMBOL(tty_hangup);
778 * tty_vhangup - process vhangup
779 * @tty: tty to hangup
781 * The user has asked via system call for the terminal to be hung up.
782 * We do this synchronously so that when the syscall returns the process
783 * is complete. That guarantee is necessary for security reasons.
786 void tty_vhangup(struct tty_struct *tty)
788 #ifdef TTY_DEBUG_HANGUP
789 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty));
791 __tty_hangup(tty, 0);
794 EXPORT_SYMBOL(tty_vhangup);
798 * tty_vhangup_self - process vhangup for own ctty
800 * Perform a vhangup on the current controlling tty
803 void tty_vhangup_self(void)
805 struct tty_struct *tty;
807 tty = get_current_tty();
815 * tty_vhangup_session - hangup session leader exit
816 * @tty: tty to hangup
818 * The session leader is exiting and hanging up its controlling terminal.
819 * Every process in the foreground process group is signalled SIGHUP.
821 * We do this synchronously so that when the syscall returns the process
822 * is complete. That guarantee is necessary for security reasons.
825 static void tty_vhangup_session(struct tty_struct *tty)
827 #ifdef TTY_DEBUG_HANGUP
828 printk(KERN_DEBUG "%s vhangup session...\n", tty_name(tty));
830 __tty_hangup(tty, 1);
834 * tty_hung_up_p - was tty hung up
835 * @filp: file pointer of tty
837 * Return true if the tty has been subject to a vhangup or a carrier
841 int tty_hung_up_p(struct file *filp)
843 return (filp->f_op == &hung_up_tty_fops);
846 EXPORT_SYMBOL(tty_hung_up_p);
849 * disassociate_ctty - disconnect controlling tty
850 * @on_exit: true if exiting so need to "hang up" the session
852 * This function is typically called only by the session leader, when
853 * it wants to disassociate itself from its controlling tty.
855 * It performs the following functions:
856 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
857 * (2) Clears the tty from being controlling the session
858 * (3) Clears the controlling tty for all processes in the
861 * The argument on_exit is set to 1 if called when a process is
862 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
865 * BTM is taken for hysterical raisins, and held when
866 * called from no_tty().
867 * tty_mutex is taken to protect tty
868 * ->siglock is taken to protect ->signal/->sighand
869 * tasklist_lock is taken to walk process list for sessions
870 * ->siglock is taken to protect ->signal/->sighand
873 void disassociate_ctty(int on_exit)
875 struct tty_struct *tty;
877 if (!current->signal->leader)
880 tty = get_current_tty();
882 if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) {
883 tty_vhangup_session(tty);
885 struct pid *tty_pgrp = tty_get_pgrp(tty);
887 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
889 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
895 } else if (on_exit) {
896 struct pid *old_pgrp;
897 spin_lock_irq(¤t->sighand->siglock);
898 old_pgrp = current->signal->tty_old_pgrp;
899 current->signal->tty_old_pgrp = NULL;
900 spin_unlock_irq(¤t->sighand->siglock);
902 kill_pgrp(old_pgrp, SIGHUP, on_exit);
903 kill_pgrp(old_pgrp, SIGCONT, on_exit);
909 spin_lock_irq(¤t->sighand->siglock);
910 put_pid(current->signal->tty_old_pgrp);
911 current->signal->tty_old_pgrp = NULL;
913 tty = tty_kref_get(current->signal->tty);
916 spin_lock_irqsave(&tty->ctrl_lock, flags);
917 put_pid(tty->session);
921 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
924 #ifdef TTY_DEBUG_HANGUP
925 printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
930 spin_unlock_irq(¤t->sighand->siglock);
931 /* Now clear signal->tty under the lock */
932 read_lock(&tasklist_lock);
933 session_clear_tty(task_session(current));
934 read_unlock(&tasklist_lock);
939 * no_tty - Ensure the current process does not have a controlling tty
943 /* FIXME: Review locking here. The tty_lock never covered any race
944 between a new association and proc_clear_tty but possible we need
945 to protect against this anyway */
946 struct task_struct *tsk = current;
947 disassociate_ctty(0);
953 * stop_tty - propagate flow control
956 * Perform flow control to the driver. May be called
957 * on an already stopped device and will not re-call the driver
960 * This functionality is used by both the line disciplines for
961 * halting incoming flow and by the driver. It may therefore be
962 * called from any context, may be under the tty atomic_write_lock
969 void __stop_tty(struct tty_struct *tty)
978 void stop_tty(struct tty_struct *tty)
982 spin_lock_irqsave(&tty->flow_lock, flags);
984 spin_unlock_irqrestore(&tty->flow_lock, flags);
986 EXPORT_SYMBOL(stop_tty);
989 * start_tty - propagate flow control
992 * Start a tty that has been stopped if at all possible. If this
993 * tty was previous stopped and is now being started, the driver
994 * start method is invoked and the line discipline woken.
1000 void __start_tty(struct tty_struct *tty)
1002 if (!tty->stopped || tty->flow_stopped)
1005 if (tty->ops->start)
1006 tty->ops->start(tty);
1010 void start_tty(struct tty_struct *tty)
1012 unsigned long flags;
1014 spin_lock_irqsave(&tty->flow_lock, flags);
1016 spin_unlock_irqrestore(&tty->flow_lock, flags);
1018 EXPORT_SYMBOL(start_tty);
1020 static void tty_update_time(struct timespec *time)
1022 unsigned long sec = get_seconds();
1025 * We only care if the two values differ in anything other than the
1026 * lower three bits (i.e every 8 seconds). If so, then we can update
1027 * the time of the tty device, otherwise it could be construded as a
1028 * security leak to let userspace know the exact timing of the tty.
1030 if ((sec ^ time->tv_sec) & ~7)
1035 * tty_read - read method for tty device files
1036 * @file: pointer to tty file
1038 * @count: size of user buffer
1041 * Perform the read system call function on this terminal device. Checks
1042 * for hung up devices before calling the line discipline method.
1045 * Locks the line discipline internally while needed. Multiple
1046 * read calls may be outstanding in parallel.
1049 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
1053 struct inode *inode = file_inode(file);
1054 struct tty_struct *tty = file_tty(file);
1055 struct tty_ldisc *ld;
1057 if (tty_paranoia_check(tty, inode, "tty_read"))
1059 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
1062 /* We want to wait for the line discipline to sort out in this
1064 ld = tty_ldisc_ref_wait(tty);
1066 i = ld->ops->read(tty, file, buf, count);
1069 tty_ldisc_deref(ld);
1072 tty_update_time(&inode->i_atime);
1077 static void tty_write_unlock(struct tty_struct *tty)
1079 mutex_unlock(&tty->atomic_write_lock);
1080 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
1083 static int tty_write_lock(struct tty_struct *tty, int ndelay)
1085 if (!mutex_trylock(&tty->atomic_write_lock)) {
1088 if (mutex_lock_interruptible(&tty->atomic_write_lock))
1089 return -ERESTARTSYS;
1095 * Split writes up in sane blocksizes to avoid
1096 * denial-of-service type attacks
1098 static inline ssize_t do_tty_write(
1099 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
1100 struct tty_struct *tty,
1102 const char __user *buf,
1105 ssize_t ret, written = 0;
1108 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
1113 * We chunk up writes into a temporary buffer. This
1114 * simplifies low-level drivers immensely, since they
1115 * don't have locking issues and user mode accesses.
1117 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1120 * The default chunk-size is 2kB, because the NTTY
1121 * layer has problems with bigger chunks. It will
1122 * claim to be able to handle more characters than
1125 * FIXME: This can probably go away now except that 64K chunks
1126 * are too likely to fail unless switched to vmalloc...
1129 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1134 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1135 if (tty->write_cnt < chunk) {
1136 unsigned char *buf_chunk;
1141 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1146 kfree(tty->write_buf);
1147 tty->write_cnt = chunk;
1148 tty->write_buf = buf_chunk;
1151 /* Do the write .. */
1153 size_t size = count;
1157 if (copy_from_user(tty->write_buf, buf, size))
1159 ret = write(tty, file, tty->write_buf, size);
1168 if (signal_pending(current))
1173 tty_update_time(&file_inode(file)->i_mtime);
1177 tty_write_unlock(tty);
1182 * tty_write_message - write a message to a certain tty, not just the console.
1183 * @tty: the destination tty_struct
1184 * @msg: the message to write
1186 * This is used for messages that need to be redirected to a specific tty.
1187 * We don't put it into the syslog queue right now maybe in the future if
1190 * We must still hold the BTM and test the CLOSING flag for the moment.
1193 void tty_write_message(struct tty_struct *tty, char *msg)
1196 mutex_lock(&tty->atomic_write_lock);
1198 if (tty->ops->write && tty->count > 0) {
1200 tty->ops->write(tty, msg, strlen(msg));
1203 tty_write_unlock(tty);
1210 * tty_write - write method for tty device file
1211 * @file: tty file pointer
1212 * @buf: user data to write
1213 * @count: bytes to write
1216 * Write data to a tty device via the line discipline.
1219 * Locks the line discipline as required
1220 * Writes to the tty driver are serialized by the atomic_write_lock
1221 * and are then processed in chunks to the device. The line discipline
1222 * write method will not be invoked in parallel for each device.
1225 static ssize_t tty_write(struct file *file, const char __user *buf,
1226 size_t count, loff_t *ppos)
1228 struct tty_struct *tty = file_tty(file);
1229 struct tty_ldisc *ld;
1232 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1234 if (!tty || !tty->ops->write ||
1235 (test_bit(TTY_IO_ERROR, &tty->flags)))
1237 /* Short term debug to catch buggy drivers */
1238 if (tty->ops->write_room == NULL)
1239 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1241 ld = tty_ldisc_ref_wait(tty);
1242 if (!ld->ops->write)
1245 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1246 tty_ldisc_deref(ld);
1250 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1251 size_t count, loff_t *ppos)
1253 struct file *p = NULL;
1255 spin_lock(&redirect_lock);
1257 p = get_file(redirect);
1258 spin_unlock(&redirect_lock);
1262 res = vfs_write(p, buf, count, &p->f_pos);
1266 return tty_write(file, buf, count, ppos);
1270 * tty_send_xchar - send priority character
1272 * Send a high priority character to the tty even if stopped
1274 * Locking: none for xchar method, write ordering for write method.
1277 int tty_send_xchar(struct tty_struct *tty, char ch)
1279 int was_stopped = tty->stopped;
1281 if (tty->ops->send_xchar) {
1282 tty->ops->send_xchar(tty, ch);
1286 if (tty_write_lock(tty, 0) < 0)
1287 return -ERESTARTSYS;
1291 tty->ops->write(tty, &ch, 1);
1294 tty_write_unlock(tty);
1298 static char ptychar[] = "pqrstuvwxyzabcde";
1301 * pty_line_name - generate name for a pty
1302 * @driver: the tty driver in use
1303 * @index: the minor number
1304 * @p: output buffer of at least 6 bytes
1306 * Generate a name from a driver reference and write it to the output
1311 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1313 int i = index + driver->name_base;
1314 /* ->name is initialized to "ttyp", but "tty" is expected */
1315 sprintf(p, "%s%c%x",
1316 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1317 ptychar[i >> 4 & 0xf], i & 0xf);
1321 * tty_line_name - generate name for a tty
1322 * @driver: the tty driver in use
1323 * @index: the minor number
1324 * @p: output buffer of at least 7 bytes
1326 * Generate a name from a driver reference and write it to the output
1331 static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1333 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1334 return sprintf(p, "%s", driver->name);
1336 return sprintf(p, "%s%d", driver->name,
1337 index + driver->name_base);
1341 * tty_driver_lookup_tty() - find an existing tty, if any
1342 * @driver: the driver for the tty
1343 * @idx: the minor number
1345 * Return the tty, if found. If not found, return NULL or ERR_PTR() if the
1346 * driver lookup() method returns an error.
1348 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1350 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1351 struct inode *inode, int idx)
1353 struct tty_struct *tty;
1355 if (driver->ops->lookup)
1356 tty = driver->ops->lookup(driver, inode, idx);
1358 tty = driver->ttys[idx];
1366 * tty_init_termios - helper for termios setup
1367 * @tty: the tty to set up
1369 * Initialise the termios structures for this tty. Thus runs under
1370 * the tty_mutex currently so we can be relaxed about ordering.
1373 int tty_init_termios(struct tty_struct *tty)
1375 struct ktermios *tp;
1376 int idx = tty->index;
1378 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1379 tty->termios = tty->driver->init_termios;
1381 /* Check for lazy saved data */
1382 tp = tty->driver->termios[idx];
1386 tty->termios = tty->driver->init_termios;
1388 /* Compatibility until drivers always set this */
1389 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1390 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1393 EXPORT_SYMBOL_GPL(tty_init_termios);
1395 int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1397 int ret = tty_init_termios(tty);
1401 tty_driver_kref_get(driver);
1403 driver->ttys[tty->index] = tty;
1406 EXPORT_SYMBOL_GPL(tty_standard_install);
1409 * tty_driver_install_tty() - install a tty entry in the driver
1410 * @driver: the driver for the tty
1413 * Install a tty object into the driver tables. The tty->index field
1414 * will be set by the time this is called. This method is responsible
1415 * for ensuring any need additional structures are allocated and
1418 * Locking: tty_mutex for now
1420 static int tty_driver_install_tty(struct tty_driver *driver,
1421 struct tty_struct *tty)
1423 return driver->ops->install ? driver->ops->install(driver, tty) :
1424 tty_standard_install(driver, tty);
1428 * tty_driver_remove_tty() - remove a tty from the driver tables
1429 * @driver: the driver for the tty
1430 * @idx: the minor number
1432 * Remvoe a tty object from the driver tables. The tty->index field
1433 * will be set by the time this is called.
1435 * Locking: tty_mutex for now
1437 void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1439 if (driver->ops->remove)
1440 driver->ops->remove(driver, tty);
1442 driver->ttys[tty->index] = NULL;
1446 * tty_reopen() - fast re-open of an open tty
1447 * @tty - the tty to open
1449 * Return 0 on success, -errno on error.
1450 * Re-opens on master ptys are not allowed and return -EIO.
1452 * Locking: Caller must hold tty_lock
1454 static int tty_reopen(struct tty_struct *tty)
1456 struct tty_driver *driver = tty->driver;
1461 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1462 driver->subtype == PTY_TYPE_MASTER)
1465 if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
1470 WARN_ON(!tty->ldisc);
1476 * tty_init_dev - initialise a tty device
1477 * @driver: tty driver we are opening a device on
1478 * @idx: device index
1479 * @ret_tty: returned tty structure
1481 * Prepare a tty device. This may not be a "new" clean device but
1482 * could also be an active device. The pty drivers require special
1483 * handling because of this.
1486 * The function is called under the tty_mutex, which
1487 * protects us from the tty struct or driver itself going away.
1489 * On exit the tty device has the line discipline attached and
1490 * a reference count of 1. If a pair was created for pty/tty use
1491 * and the other was a pty master then it too has a reference count of 1.
1493 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1494 * failed open. The new code protects the open with a mutex, so it's
1495 * really quite straightforward. The mutex locking can probably be
1496 * relaxed for the (most common) case of reopening a tty.
1499 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1501 struct tty_struct *tty;
1505 * First time open is complex, especially for PTY devices.
1506 * This code guarantees that either everything succeeds and the
1507 * TTY is ready for operation, or else the table slots are vacated
1508 * and the allocated memory released. (Except that the termios
1509 * and locked termios may be retained.)
1512 if (!try_module_get(driver->owner))
1513 return ERR_PTR(-ENODEV);
1515 tty = alloc_tty_struct(driver, idx);
1518 goto err_module_put;
1522 retval = tty_driver_install_tty(driver, tty);
1524 goto err_deinit_tty;
1527 tty->port = driver->ports[idx];
1529 WARN_RATELIMIT(!tty->port,
1530 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1531 __func__, tty->driver->name);
1533 tty->port->itty = tty;
1536 * Structures all installed ... call the ldisc open routines.
1537 * If we fail here just call release_tty to clean up. No need
1538 * to decrement the use counts, as release_tty doesn't care.
1540 retval = tty_ldisc_setup(tty, tty->link);
1542 goto err_release_tty;
1543 /* Return the tty locked so that it cannot vanish under the caller */
1548 deinitialize_tty_struct(tty);
1549 free_tty_struct(tty);
1551 module_put(driver->owner);
1552 return ERR_PTR(retval);
1554 /* call the tty release_tty routine to clean out this slot */
1557 printk_ratelimited(KERN_INFO "tty_init_dev: ldisc open failed, "
1558 "clearing slot %d\n", idx);
1559 release_tty(tty, idx);
1560 return ERR_PTR(retval);
1563 void tty_free_termios(struct tty_struct *tty)
1565 struct ktermios *tp;
1566 int idx = tty->index;
1568 /* If the port is going to reset then it has no termios to save */
1569 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1572 /* Stash the termios data */
1573 tp = tty->driver->termios[idx];
1575 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1577 pr_warn("tty: no memory to save termios state.\n");
1580 tty->driver->termios[idx] = tp;
1584 EXPORT_SYMBOL(tty_free_termios);
1587 * tty_flush_works - flush all works of a tty/pty pair
1588 * @tty: tty device to flush works for (or either end of a pty pair)
1590 * Sync flush all works belonging to @tty (and the 'other' tty).
1592 static void tty_flush_works(struct tty_struct *tty)
1594 flush_work(&tty->SAK_work);
1595 flush_work(&tty->hangup_work);
1597 flush_work(&tty->link->SAK_work);
1598 flush_work(&tty->link->hangup_work);
1603 * release_one_tty - release tty structure memory
1604 * @kref: kref of tty we are obliterating
1606 * Releases memory associated with a tty structure, and clears out the
1607 * driver table slots. This function is called when a device is no longer
1608 * in use. It also gets called when setup of a device fails.
1611 * takes the file list lock internally when working on the list
1612 * of ttys that the driver keeps.
1614 * This method gets called from a work queue so that the driver private
1615 * cleanup ops can sleep (needed for USB at least)
1617 static void release_one_tty(struct work_struct *work)
1619 struct tty_struct *tty =
1620 container_of(work, struct tty_struct, hangup_work);
1621 struct tty_driver *driver = tty->driver;
1622 struct module *owner = driver->owner;
1624 if (tty->ops->cleanup)
1625 tty->ops->cleanup(tty);
1628 tty_driver_kref_put(driver);
1631 spin_lock(&tty_files_lock);
1632 list_del_init(&tty->tty_files);
1633 spin_unlock(&tty_files_lock);
1636 put_pid(tty->session);
1637 free_tty_struct(tty);
1640 static void queue_release_one_tty(struct kref *kref)
1642 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1644 /* The hangup queue is now free so we can reuse it rather than
1645 waste a chunk of memory for each port */
1646 INIT_WORK(&tty->hangup_work, release_one_tty);
1647 schedule_work(&tty->hangup_work);
1651 * tty_kref_put - release a tty kref
1654 * Release a reference to a tty device and if need be let the kref
1655 * layer destruct the object for us
1658 void tty_kref_put(struct tty_struct *tty)
1661 kref_put(&tty->kref, queue_release_one_tty);
1663 EXPORT_SYMBOL(tty_kref_put);
1666 * release_tty - release tty structure memory
1668 * Release both @tty and a possible linked partner (think pty pair),
1669 * and decrement the refcount of the backing module.
1673 * takes the file list lock internally when working on the list
1674 * of ttys that the driver keeps.
1677 static void release_tty(struct tty_struct *tty, int idx)
1679 /* This should always be true but check for the moment */
1680 WARN_ON(tty->index != idx);
1681 WARN_ON(!mutex_is_locked(&tty_mutex));
1682 if (tty->ops->shutdown)
1683 tty->ops->shutdown(tty);
1684 tty_free_termios(tty);
1685 tty_driver_remove_tty(tty->driver, tty);
1686 tty->port->itty = NULL;
1688 tty->link->port->itty = NULL;
1689 cancel_work_sync(&tty->port->buf.work);
1691 tty_kref_put(tty->link);
1696 * tty_release_checks - check a tty before real release
1697 * @tty: tty to check
1698 * @o_tty: link of @tty (if any)
1699 * @idx: index of the tty
1701 * Performs some paranoid checking before true release of the @tty.
1702 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1704 static int tty_release_checks(struct tty_struct *tty, int idx)
1706 #ifdef TTY_PARANOIA_CHECK
1707 if (idx < 0 || idx >= tty->driver->num) {
1708 printk(KERN_DEBUG "%s: bad idx when trying to free (%s)\n",
1709 __func__, tty->name);
1713 /* not much to check for devpts */
1714 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1717 if (tty != tty->driver->ttys[idx]) {
1718 printk(KERN_DEBUG "%s: driver.table[%d] not tty for (%s)\n",
1719 __func__, idx, tty->name);
1722 if (tty->driver->other) {
1723 struct tty_struct *o_tty = tty->link;
1725 if (o_tty != tty->driver->other->ttys[idx]) {
1726 printk(KERN_DEBUG "%s: other->table[%d] not o_tty for (%s)\n",
1727 __func__, idx, tty->name);
1730 if (o_tty->link != tty) {
1731 printk(KERN_DEBUG "%s: bad pty pointers\n", __func__);
1740 * tty_release - vfs callback for close
1741 * @inode: inode of tty
1742 * @filp: file pointer for handle to tty
1744 * Called the last time each file handle is closed that references
1745 * this tty. There may however be several such references.
1748 * Takes bkl. See tty_release_dev
1750 * Even releasing the tty structures is a tricky business.. We have
1751 * to be very careful that the structures are all released at the
1752 * same time, as interrupts might otherwise get the wrong pointers.
1754 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1755 * lead to double frees or releasing memory still in use.
1758 int tty_release(struct inode *inode, struct file *filp)
1760 struct tty_struct *tty = file_tty(filp);
1761 struct tty_struct *o_tty = NULL;
1762 int do_sleep, final;
1767 if (tty_paranoia_check(tty, inode, __func__))
1771 check_tty_count(tty, __func__);
1773 __tty_fasync(-1, filp, 0);
1776 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1777 tty->driver->subtype == PTY_TYPE_MASTER)
1780 if (tty_release_checks(tty, idx)) {
1785 #ifdef TTY_DEBUG_HANGUP
1786 printk(KERN_DEBUG "%s: %s (tty count=%d)...\n", __func__,
1787 tty_name(tty), 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 printk(KERN_WARNING "%s: %s: read/write wait queue active!\n",
1838 __func__, tty_name(tty));
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 printk(KERN_WARNING "%s: bad pty slave count (%d) for %s\n",
1850 __func__, o_tty->count, tty_name(o_tty));
1854 if (--tty->count < 0) {
1855 printk(KERN_WARNING "%s: bad tty->count (%d) for %s\n",
1856 __func__, tty->count, tty_name(tty));
1861 * We've decremented tty->count, so we need to remove this file
1862 * descriptor off the tty->tty_files list; this serves two
1864 * - check_tty_count sees the correct number of file descriptors
1865 * associated with this tty.
1866 * - do_tty_hangup no longer sees this file descriptor as
1867 * something that needs to be handled for hangups.
1872 * Perform some housekeeping before deciding whether to return.
1874 * If _either_ side is closing, make sure there aren't any
1875 * processes that still think tty or o_tty is their controlling
1879 read_lock(&tasklist_lock);
1880 session_clear_tty(tty->session);
1882 session_clear_tty(o_tty->session);
1883 read_unlock(&tasklist_lock);
1886 /* check whether both sides are closing ... */
1887 final = !tty->count && !(o_tty && o_tty->count);
1889 tty_unlock_slave(o_tty);
1892 /* At this point, the tty->count == 0 should ensure a dead tty
1893 cannot be re-opened by a racing opener */
1898 #ifdef TTY_DEBUG_HANGUP
1899 printk(KERN_DEBUG "%s: %s: final close\n", __func__, tty_name(tty));
1902 * Ask the line discipline code to release its structures
1904 tty_ldisc_release(tty);
1906 /* Wait for pending work before tty destruction commmences */
1907 tty_flush_works(tty);
1909 #ifdef TTY_DEBUG_HANGUP
1910 printk(KERN_DEBUG "%s: %s: freeing structure...\n", __func__,
1914 * The release_tty function takes care of the details of clearing
1915 * the slots and preserving the termios structure. The tty_unlock_pair
1916 * should be safe as we keep a kref while the tty is locked (so the
1917 * unlock never unlocks a freed tty).
1919 mutex_lock(&tty_mutex);
1920 release_tty(tty, idx);
1921 mutex_unlock(&tty_mutex);
1927 * tty_open_current_tty - get locked tty of current task
1928 * @device: device number
1929 * @filp: file pointer to tty
1930 * @return: locked tty of the current task iff @device is /dev/tty
1932 * Performs a re-open of the current task's controlling tty.
1934 * We cannot return driver and index like for the other nodes because
1935 * devpts will not work then. It expects inodes to be from devpts FS.
1937 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1939 struct tty_struct *tty;
1942 if (device != MKDEV(TTYAUX_MAJOR, 0))
1945 tty = get_current_tty();
1947 return ERR_PTR(-ENXIO);
1949 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1952 tty_kref_put(tty); /* safe to drop the kref now */
1954 retval = tty_reopen(tty);
1957 tty = ERR_PTR(retval);
1963 * tty_lookup_driver - lookup a tty driver for a given device file
1964 * @device: device number
1965 * @filp: file pointer to tty
1966 * @noctty: set if the device should not become a controlling tty
1967 * @index: index for the device in the @return driver
1968 * @return: driver for this inode (with increased refcount)
1970 * If @return is not erroneous, the caller is responsible to decrement the
1971 * refcount by tty_driver_kref_put.
1973 * Locking: tty_mutex protects get_tty_driver
1975 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1976 int *noctty, int *index)
1978 struct tty_driver *driver;
1982 case MKDEV(TTY_MAJOR, 0): {
1983 extern struct tty_driver *console_driver;
1984 driver = tty_driver_kref_get(console_driver);
1985 *index = fg_console;
1990 case MKDEV(TTYAUX_MAJOR, 1): {
1991 struct tty_driver *console_driver = console_device(index);
1992 if (console_driver) {
1993 driver = tty_driver_kref_get(console_driver);
1995 /* Don't let /dev/console block */
1996 filp->f_flags |= O_NONBLOCK;
2001 return ERR_PTR(-ENODEV);
2004 driver = get_tty_driver(device, index);
2006 return ERR_PTR(-ENODEV);
2013 * tty_open - open a tty device
2014 * @inode: inode of device file
2015 * @filp: file pointer to tty
2017 * tty_open and tty_release keep up the tty count that contains the
2018 * number of opens done on a tty. We cannot use the inode-count, as
2019 * different inodes might point to the same tty.
2021 * Open-counting is needed for pty masters, as well as for keeping
2022 * track of serial lines: DTR is dropped when the last close happens.
2023 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2025 * The termios state of a pty is reset on first open so that
2026 * settings don't persist across reuse.
2028 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
2029 * tty->count should protect the rest.
2030 * ->siglock protects ->signal/->sighand
2032 * Note: the tty_unlock/lock cases without a ref are only safe due to
2036 static int tty_open(struct inode *inode, struct file *filp)
2038 struct tty_struct *tty;
2040 struct tty_driver *driver = NULL;
2042 dev_t device = inode->i_rdev;
2043 unsigned saved_flags = filp->f_flags;
2045 nonseekable_open(inode, filp);
2048 retval = tty_alloc_file(filp);
2052 noctty = filp->f_flags & O_NOCTTY;
2056 tty = tty_open_current_tty(device, filp);
2058 mutex_lock(&tty_mutex);
2059 driver = tty_lookup_driver(device, filp, &noctty, &index);
2060 if (IS_ERR(driver)) {
2061 retval = PTR_ERR(driver);
2065 /* check whether we're reopening an existing tty */
2066 tty = tty_driver_lookup_tty(driver, inode, index);
2068 retval = PTR_ERR(tty);
2073 mutex_unlock(&tty_mutex);
2075 /* safe to drop the kref from tty_driver_lookup_tty() */
2077 retval = tty_reopen(tty);
2080 tty = ERR_PTR(retval);
2082 } else { /* Returns with the tty_lock held for now */
2083 tty = tty_init_dev(driver, index);
2084 mutex_unlock(&tty_mutex);
2087 tty_driver_kref_put(driver);
2091 retval = PTR_ERR(tty);
2095 tty_add_file(tty, filp);
2097 check_tty_count(tty, __func__);
2098 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2099 tty->driver->subtype == PTY_TYPE_MASTER)
2101 #ifdef TTY_DEBUG_HANGUP
2102 printk(KERN_DEBUG "%s: opening %s...\n", __func__, tty->name);
2105 retval = tty->ops->open(tty, filp);
2108 filp->f_flags = saved_flags;
2111 #ifdef TTY_DEBUG_HANGUP
2112 printk(KERN_DEBUG "%s: error %d in opening %s...\n", __func__,
2115 tty_unlock(tty); /* need to call tty_release without BTM */
2116 tty_release(inode, filp);
2117 if (retval != -ERESTARTSYS)
2120 if (signal_pending(current))
2125 * Need to reset f_op in case a hangup happened.
2127 if (tty_hung_up_p(filp))
2128 filp->f_op = &tty_fops;
2131 clear_bit(TTY_HUPPED, &tty->flags);
2134 read_lock(&tasklist_lock);
2135 spin_lock_irq(¤t->sighand->siglock);
2137 current->signal->leader &&
2138 !current->signal->tty &&
2139 tty->session == NULL)
2140 __proc_set_tty(tty);
2141 spin_unlock_irq(¤t->sighand->siglock);
2142 read_unlock(&tasklist_lock);
2146 mutex_unlock(&tty_mutex);
2147 /* after locks to avoid deadlock */
2148 if (!IS_ERR_OR_NULL(driver))
2149 tty_driver_kref_put(driver);
2151 tty_free_file(filp);
2158 * tty_poll - check tty status
2159 * @filp: file being polled
2160 * @wait: poll wait structures to update
2162 * Call the line discipline polling method to obtain the poll
2163 * status of the device.
2165 * Locking: locks called line discipline but ldisc poll method
2166 * may be re-entered freely by other callers.
2169 static unsigned int tty_poll(struct file *filp, poll_table *wait)
2171 struct tty_struct *tty = file_tty(filp);
2172 struct tty_ldisc *ld;
2175 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2178 ld = tty_ldisc_ref_wait(tty);
2180 ret = ld->ops->poll(tty, filp, wait);
2181 tty_ldisc_deref(ld);
2185 static int __tty_fasync(int fd, struct file *filp, int on)
2187 struct tty_struct *tty = file_tty(filp);
2188 struct tty_ldisc *ldisc;
2189 unsigned long flags;
2192 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2195 retval = fasync_helper(fd, filp, on, &tty->fasync);
2199 ldisc = tty_ldisc_ref(tty);
2201 if (ldisc->ops->fasync)
2202 ldisc->ops->fasync(tty, on);
2203 tty_ldisc_deref(ldisc);
2210 spin_lock_irqsave(&tty->ctrl_lock, flags);
2213 type = PIDTYPE_PGID;
2215 pid = task_pid(current);
2219 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2220 __f_setown(filp, pid, type, 0);
2228 static int tty_fasync(int fd, struct file *filp, int on)
2230 struct tty_struct *tty = file_tty(filp);
2234 retval = __tty_fasync(fd, filp, on);
2241 * tiocsti - fake input character
2242 * @tty: tty to fake input into
2243 * @p: pointer to character
2245 * Fake input to a tty device. Does the necessary locking and
2248 * FIXME: does not honour flow control ??
2251 * Called functions take tty_ldiscs_lock
2252 * current->signal->tty check is safe without locks
2254 * FIXME: may race normal receive processing
2257 static int tiocsti(struct tty_struct *tty, char __user *p)
2260 struct tty_ldisc *ld;
2262 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2264 if (get_user(ch, p))
2266 tty_audit_tiocsti(tty, ch);
2267 ld = tty_ldisc_ref_wait(tty);
2268 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2269 tty_ldisc_deref(ld);
2274 * tiocgwinsz - implement window query ioctl
2276 * @arg: user buffer for result
2278 * Copies the kernel idea of the window size into the user buffer.
2280 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2284 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2288 mutex_lock(&tty->winsize_mutex);
2289 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2290 mutex_unlock(&tty->winsize_mutex);
2292 return err ? -EFAULT: 0;
2296 * tty_do_resize - resize event
2297 * @tty: tty being resized
2298 * @rows: rows (character)
2299 * @cols: cols (character)
2301 * Update the termios variables and send the necessary signals to
2302 * peform a terminal resize correctly
2305 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2310 mutex_lock(&tty->winsize_mutex);
2311 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2314 /* Signal the foreground process group */
2315 pgrp = tty_get_pgrp(tty);
2317 kill_pgrp(pgrp, SIGWINCH, 1);
2322 mutex_unlock(&tty->winsize_mutex);
2325 EXPORT_SYMBOL(tty_do_resize);
2328 * tiocswinsz - implement window size set ioctl
2329 * @tty; tty side of tty
2330 * @arg: user buffer for result
2332 * Copies the user idea of the window size to the kernel. Traditionally
2333 * this is just advisory information but for the Linux console it
2334 * actually has driver level meaning and triggers a VC resize.
2337 * Driver dependent. The default do_resize method takes the
2338 * tty termios mutex and ctrl_lock. The console takes its own lock
2339 * then calls into the default method.
2342 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2344 struct winsize tmp_ws;
2345 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2348 if (tty->ops->resize)
2349 return tty->ops->resize(tty, &tmp_ws);
2351 return tty_do_resize(tty, &tmp_ws);
2355 * tioccons - allow admin to move logical console
2356 * @file: the file to become console
2358 * Allow the administrator to move the redirected console device
2360 * Locking: uses redirect_lock to guard the redirect information
2363 static int tioccons(struct file *file)
2365 if (!capable(CAP_SYS_ADMIN))
2367 if (file->f_op->write == redirected_tty_write) {
2369 spin_lock(&redirect_lock);
2372 spin_unlock(&redirect_lock);
2377 spin_lock(&redirect_lock);
2379 spin_unlock(&redirect_lock);
2382 redirect = get_file(file);
2383 spin_unlock(&redirect_lock);
2388 * fionbio - non blocking ioctl
2389 * @file: file to set blocking value
2390 * @p: user parameter
2392 * Historical tty interfaces had a blocking control ioctl before
2393 * the generic functionality existed. This piece of history is preserved
2394 * in the expected tty API of posix OS's.
2396 * Locking: none, the open file handle ensures it won't go away.
2399 static int fionbio(struct file *file, int __user *p)
2403 if (get_user(nonblock, p))
2406 spin_lock(&file->f_lock);
2408 file->f_flags |= O_NONBLOCK;
2410 file->f_flags &= ~O_NONBLOCK;
2411 spin_unlock(&file->f_lock);
2416 * tiocsctty - set controlling tty
2417 * @tty: tty structure
2418 * @arg: user argument
2420 * This ioctl is used to manage job control. It permits a session
2421 * leader to set this tty as the controlling tty for the session.
2424 * Takes tty_lock() to serialize proc_set_tty() for this tty
2425 * Takes tasklist_lock internally to walk sessions
2426 * Takes ->siglock() when updating signal->tty
2429 static int tiocsctty(struct tty_struct *tty, int arg)
2434 read_lock(&tasklist_lock);
2436 if (current->signal->leader && (task_session(current) == tty->session))
2440 * The process must be a session leader and
2441 * not have a controlling tty already.
2443 if (!current->signal->leader || current->signal->tty) {
2450 * This tty is already the controlling
2451 * tty for another session group!
2453 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2457 session_clear_tty(tty->session);
2465 read_unlock(&tasklist_lock);
2471 * tty_get_pgrp - return a ref counted pgrp pid
2474 * Returns a refcounted instance of the pid struct for the process
2475 * group controlling the tty.
2478 struct pid *tty_get_pgrp(struct tty_struct *tty)
2480 unsigned long flags;
2483 spin_lock_irqsave(&tty->ctrl_lock, flags);
2484 pgrp = get_pid(tty->pgrp);
2485 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2489 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2492 * This checks not only the pgrp, but falls back on the pid if no
2493 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
2496 * The caller must hold rcu lock or the tasklist lock.
2498 static struct pid *session_of_pgrp(struct pid *pgrp)
2500 struct task_struct *p;
2501 struct pid *sid = NULL;
2503 p = pid_task(pgrp, PIDTYPE_PGID);
2505 p = pid_task(pgrp, PIDTYPE_PID);
2507 sid = task_session(p);
2513 * tiocgpgrp - get process group
2514 * @tty: tty passed by user
2515 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2518 * Obtain the process group of the tty. If there is no process group
2521 * Locking: none. Reference to current->signal->tty is safe.
2524 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2529 * (tty == real_tty) is a cheap way of
2530 * testing if the tty is NOT a master pty.
2532 if (tty == real_tty && current->signal->tty != real_tty)
2534 pid = tty_get_pgrp(real_tty);
2535 ret = put_user(pid_vnr(pid), p);
2541 * tiocspgrp - attempt to set process group
2542 * @tty: tty passed by user
2543 * @real_tty: tty side device matching tty passed by user
2546 * Set the process group of the tty to the session passed. Only
2547 * permitted where the tty session is our session.
2549 * Locking: RCU, ctrl lock
2552 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2556 int retval = tty_check_change(real_tty);
2557 unsigned long flags;
2563 if (!current->signal->tty ||
2564 (current->signal->tty != real_tty) ||
2565 (real_tty->session != task_session(current)))
2567 if (get_user(pgrp_nr, p))
2572 pgrp = find_vpid(pgrp_nr);
2577 if (session_of_pgrp(pgrp) != task_session(current))
2580 spin_lock_irqsave(&tty->ctrl_lock, flags);
2581 put_pid(real_tty->pgrp);
2582 real_tty->pgrp = get_pid(pgrp);
2583 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2590 * tiocgsid - get session id
2591 * @tty: tty passed by user
2592 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2593 * @p: pointer to returned session id
2595 * Obtain the session id of the tty. If there is no session
2598 * Locking: none. Reference to current->signal->tty is safe.
2601 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2604 * (tty == real_tty) is a cheap way of
2605 * testing if the tty is NOT a master pty.
2607 if (tty == real_tty && current->signal->tty != real_tty)
2609 if (!real_tty->session)
2611 return put_user(pid_vnr(real_tty->session), p);
2615 * tiocsetd - set line discipline
2617 * @p: pointer to user data
2619 * Set the line discipline according to user request.
2621 * Locking: see tty_set_ldisc, this function is just a helper
2624 static int tiocsetd(struct tty_struct *tty, int __user *p)
2629 if (get_user(ldisc, p))
2632 ret = tty_set_ldisc(tty, ldisc);
2638 * send_break - performed time break
2639 * @tty: device to break on
2640 * @duration: timeout in mS
2642 * Perform a timed break on hardware that lacks its own driver level
2643 * timed break functionality.
2646 * atomic_write_lock serializes
2650 static int send_break(struct tty_struct *tty, unsigned int duration)
2654 if (tty->ops->break_ctl == NULL)
2657 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2658 retval = tty->ops->break_ctl(tty, duration);
2660 /* Do the work ourselves */
2661 if (tty_write_lock(tty, 0) < 0)
2663 retval = tty->ops->break_ctl(tty, -1);
2666 if (!signal_pending(current))
2667 msleep_interruptible(duration);
2668 retval = tty->ops->break_ctl(tty, 0);
2670 tty_write_unlock(tty);
2671 if (signal_pending(current))
2678 * tty_tiocmget - get modem status
2680 * @file: user file pointer
2681 * @p: pointer to result
2683 * Obtain the modem status bits from the tty driver if the feature
2684 * is supported. Return -EINVAL if it is not available.
2686 * Locking: none (up to the driver)
2689 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2691 int retval = -EINVAL;
2693 if (tty->ops->tiocmget) {
2694 retval = tty->ops->tiocmget(tty);
2697 retval = put_user(retval, p);
2703 * tty_tiocmset - set modem status
2705 * @cmd: command - clear bits, set bits or set all
2706 * @p: pointer to desired bits
2708 * Set the modem status bits from the tty driver if the feature
2709 * is supported. Return -EINVAL if it is not available.
2711 * Locking: none (up to the driver)
2714 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2718 unsigned int set, clear, val;
2720 if (tty->ops->tiocmset == NULL)
2723 retval = get_user(val, p);
2739 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2740 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2741 return tty->ops->tiocmset(tty, set, clear);
2744 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2746 int retval = -EINVAL;
2747 struct serial_icounter_struct icount;
2748 memset(&icount, 0, sizeof(icount));
2749 if (tty->ops->get_icount)
2750 retval = tty->ops->get_icount(tty, &icount);
2753 if (copy_to_user(arg, &icount, sizeof(icount)))
2758 static void tty_warn_deprecated_flags(struct serial_struct __user *ss)
2760 static DEFINE_RATELIMIT_STATE(depr_flags,
2761 DEFAULT_RATELIMIT_INTERVAL,
2762 DEFAULT_RATELIMIT_BURST);
2763 char comm[TASK_COMM_LEN];
2766 if (get_user(flags, &ss->flags))
2769 flags &= ASYNC_DEPRECATED;
2771 if (flags && __ratelimit(&depr_flags))
2772 pr_warning("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2773 __func__, get_task_comm(comm, current), flags);
2777 * if pty, return the slave side (real_tty)
2778 * otherwise, return self
2780 static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2782 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2783 tty->driver->subtype == PTY_TYPE_MASTER)
2789 * Split this up, as gcc can choke on it otherwise..
2791 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2793 struct tty_struct *tty = file_tty(file);
2794 struct tty_struct *real_tty;
2795 void __user *p = (void __user *)arg;
2797 struct tty_ldisc *ld;
2799 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2802 real_tty = tty_pair_get_tty(tty);
2805 * Factor out some common prep work
2813 retval = tty_check_change(tty);
2816 if (cmd != TIOCCBRK) {
2817 tty_wait_until_sent(tty, 0);
2818 if (signal_pending(current))
2829 return tiocsti(tty, p);
2831 return tiocgwinsz(real_tty, p);
2833 return tiocswinsz(real_tty, p);
2835 return real_tty != tty ? -EINVAL : tioccons(file);
2837 return fionbio(file, p);
2839 set_bit(TTY_EXCLUSIVE, &tty->flags);
2842 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2846 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2847 return put_user(excl, (int __user *)p);
2850 if (current->signal->tty != tty)
2855 return tiocsctty(tty, arg);
2857 return tiocgpgrp(tty, real_tty, p);
2859 return tiocspgrp(tty, real_tty, p);
2861 return tiocgsid(tty, real_tty, p);
2863 return put_user(tty->ldisc->ops->num, (int __user *)p);
2865 return tiocsetd(tty, p);
2867 if (!capable(CAP_SYS_ADMIN))
2873 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2874 return put_user(ret, (unsigned int __user *)p);
2879 case TIOCSBRK: /* Turn break on, unconditionally */
2880 if (tty->ops->break_ctl)
2881 return tty->ops->break_ctl(tty, -1);
2883 case TIOCCBRK: /* Turn break off, unconditionally */
2884 if (tty->ops->break_ctl)
2885 return tty->ops->break_ctl(tty, 0);
2887 case TCSBRK: /* SVID version: non-zero arg --> no break */
2888 /* non-zero arg means wait for all output data
2889 * to be sent (performed above) but don't send break.
2890 * This is used by the tcdrain() termios function.
2893 return send_break(tty, 250);
2895 case TCSBRKP: /* support for POSIX tcsendbreak() */
2896 return send_break(tty, arg ? arg*100 : 250);
2899 return tty_tiocmget(tty, p);
2903 return tty_tiocmset(tty, cmd, p);
2905 retval = tty_tiocgicount(tty, p);
2906 /* For the moment allow fall through to the old method */
2907 if (retval != -EINVAL)
2914 /* flush tty buffer and allow ldisc to process ioctl */
2915 tty_buffer_flush(tty, NULL);
2920 tty_warn_deprecated_flags(p);
2923 if (tty->ops->ioctl) {
2924 retval = tty->ops->ioctl(tty, cmd, arg);
2925 if (retval != -ENOIOCTLCMD)
2928 ld = tty_ldisc_ref_wait(tty);
2930 if (ld->ops->ioctl) {
2931 retval = ld->ops->ioctl(tty, file, cmd, arg);
2932 if (retval == -ENOIOCTLCMD)
2935 tty_ldisc_deref(ld);
2939 #ifdef CONFIG_COMPAT
2940 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2943 struct tty_struct *tty = file_tty(file);
2944 struct tty_ldisc *ld;
2945 int retval = -ENOIOCTLCMD;
2947 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2950 if (tty->ops->compat_ioctl) {
2951 retval = tty->ops->compat_ioctl(tty, cmd, arg);
2952 if (retval != -ENOIOCTLCMD)
2956 ld = tty_ldisc_ref_wait(tty);
2957 if (ld->ops->compat_ioctl)
2958 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2960 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
2961 tty_ldisc_deref(ld);
2967 static int this_tty(const void *t, struct file *file, unsigned fd)
2969 if (likely(file->f_op->read != tty_read))
2971 return file_tty(file) != t ? 0 : fd + 1;
2975 * This implements the "Secure Attention Key" --- the idea is to
2976 * prevent trojan horses by killing all processes associated with this
2977 * tty when the user hits the "Secure Attention Key". Required for
2978 * super-paranoid applications --- see the Orange Book for more details.
2980 * This code could be nicer; ideally it should send a HUP, wait a few
2981 * seconds, then send a INT, and then a KILL signal. But you then
2982 * have to coordinate with the init process, since all processes associated
2983 * with the current tty must be dead before the new getty is allowed
2986 * Now, if it would be correct ;-/ The current code has a nasty hole -
2987 * it doesn't catch files in flight. We may send the descriptor to ourselves
2988 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2990 * Nasty bug: do_SAK is being called in interrupt context. This can
2991 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2993 void __do_SAK(struct tty_struct *tty)
2998 struct task_struct *g, *p;
2999 struct pid *session;
3004 session = tty->session;
3006 tty_ldisc_flush(tty);
3008 tty_driver_flush_buffer(tty);
3010 read_lock(&tasklist_lock);
3011 /* Kill the entire session */
3012 do_each_pid_task(session, PIDTYPE_SID, p) {
3013 printk(KERN_NOTICE "SAK: killed process %d"
3014 " (%s): task_session(p)==tty->session\n",
3015 task_pid_nr(p), p->comm);
3016 send_sig(SIGKILL, p, 1);
3017 } while_each_pid_task(session, PIDTYPE_SID, p);
3018 /* Now kill any processes that happen to have the
3021 do_each_thread(g, p) {
3022 if (p->signal->tty == tty) {
3023 printk(KERN_NOTICE "SAK: killed process %d"
3024 " (%s): task_session(p)==tty->session\n",
3025 task_pid_nr(p), p->comm);
3026 send_sig(SIGKILL, p, 1);
3030 i = iterate_fd(p->files, 0, this_tty, tty);
3032 printk(KERN_NOTICE "SAK: killed process %d"
3033 " (%s): fd#%d opened to the tty\n",
3034 task_pid_nr(p), p->comm, i - 1);
3035 force_sig(SIGKILL, p);
3038 } while_each_thread(g, p);
3039 read_unlock(&tasklist_lock);
3043 static void do_SAK_work(struct work_struct *work)
3045 struct tty_struct *tty =
3046 container_of(work, struct tty_struct, SAK_work);
3051 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3052 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3053 * the values which we write to it will be identical to the values which it
3054 * already has. --akpm
3056 void do_SAK(struct tty_struct *tty)
3060 schedule_work(&tty->SAK_work);
3063 EXPORT_SYMBOL(do_SAK);
3065 static int dev_match_devt(struct device *dev, const void *data)
3067 const dev_t *devt = data;
3068 return dev->devt == *devt;
3071 /* Must put_device() after it's unused! */
3072 static struct device *tty_get_device(struct tty_struct *tty)
3074 dev_t devt = tty_devnum(tty);
3075 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
3082 * This subroutine allocates and initializes a tty structure.
3084 * Locking: none - tty in question is not exposed at this point
3087 struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
3089 struct tty_struct *tty;
3091 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
3095 kref_init(&tty->kref);
3096 tty->magic = TTY_MAGIC;
3097 tty_ldisc_init(tty);
3098 tty->session = NULL;
3100 mutex_init(&tty->legacy_mutex);
3101 mutex_init(&tty->throttle_mutex);
3102 init_rwsem(&tty->termios_rwsem);
3103 mutex_init(&tty->winsize_mutex);
3104 init_ldsem(&tty->ldisc_sem);
3105 init_waitqueue_head(&tty->write_wait);
3106 init_waitqueue_head(&tty->read_wait);
3107 INIT_WORK(&tty->hangup_work, do_tty_hangup);
3108 mutex_init(&tty->atomic_write_lock);
3109 spin_lock_init(&tty->ctrl_lock);
3110 spin_lock_init(&tty->flow_lock);
3111 INIT_LIST_HEAD(&tty->tty_files);
3112 INIT_WORK(&tty->SAK_work, do_SAK_work);
3114 tty->driver = driver;
3115 tty->ops = driver->ops;
3117 tty_line_name(driver, idx, tty->name);
3118 tty->dev = tty_get_device(tty);
3124 * deinitialize_tty_struct
3125 * @tty: tty to deinitialize
3127 * This subroutine deinitializes a tty structure that has been newly
3128 * allocated but tty_release cannot be called on that yet.
3130 * Locking: none - tty in question must not be exposed at this point
3132 void deinitialize_tty_struct(struct tty_struct *tty)
3134 tty_ldisc_deinit(tty);
3138 * tty_put_char - write one character to a tty
3142 * Write one byte to the tty using the provided put_char method
3143 * if present. Returns the number of characters successfully output.
3145 * Note: the specific put_char operation in the driver layer may go
3146 * away soon. Don't call it directly, use this method
3149 int tty_put_char(struct tty_struct *tty, unsigned char ch)
3151 if (tty->ops->put_char)
3152 return tty->ops->put_char(tty, ch);
3153 return tty->ops->write(tty, &ch, 1);
3155 EXPORT_SYMBOL_GPL(tty_put_char);
3157 struct class *tty_class;
3159 static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3160 unsigned int index, unsigned int count)
3162 /* init here, since reused cdevs cause crashes */
3163 cdev_init(&driver->cdevs[index], &tty_fops);
3164 driver->cdevs[index].owner = driver->owner;
3165 return cdev_add(&driver->cdevs[index], dev, count);
3169 * tty_register_device - register a tty device
3170 * @driver: the tty driver that describes the tty device
3171 * @index: the index in the tty driver for this tty device
3172 * @device: a struct device that is associated with this tty device.
3173 * This field is optional, if there is no known struct device
3174 * for this tty device it can be set to NULL safely.
3176 * Returns a pointer to the struct device for this tty device
3177 * (or ERR_PTR(-EFOO) on error).
3179 * This call is required to be made to register an individual tty device
3180 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3181 * that bit is not set, this function should not be called by a tty
3187 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3188 struct device *device)
3190 return tty_register_device_attr(driver, index, device, NULL, NULL);
3192 EXPORT_SYMBOL(tty_register_device);
3194 static void tty_device_create_release(struct device *dev)
3196 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3201 * tty_register_device_attr - register a tty device
3202 * @driver: the tty driver that describes the tty device
3203 * @index: the index in the tty driver for this tty device
3204 * @device: a struct device that is associated with this tty device.
3205 * This field is optional, if there is no known struct device
3206 * for this tty device it can be set to NULL safely.
3207 * @drvdata: Driver data to be set to device.
3208 * @attr_grp: Attribute group to be set on device.
3210 * Returns a pointer to the struct device for this tty device
3211 * (or ERR_PTR(-EFOO) on error).
3213 * This call is required to be made to register an individual tty device
3214 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3215 * that bit is not set, this function should not be called by a tty
3220 struct device *tty_register_device_attr(struct tty_driver *driver,
3221 unsigned index, struct device *device,
3223 const struct attribute_group **attr_grp)
3226 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3227 struct device *dev = NULL;
3228 int retval = -ENODEV;
3231 if (index >= driver->num) {
3232 printk(KERN_ERR "Attempt to register invalid tty line number "
3234 return ERR_PTR(-EINVAL);
3237 if (driver->type == TTY_DRIVER_TYPE_PTY)
3238 pty_line_name(driver, index, name);
3240 tty_line_name(driver, index, name);
3242 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3243 retval = tty_cdev_add(driver, devt, index, 1);
3249 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3256 dev->class = tty_class;
3257 dev->parent = device;
3258 dev->release = tty_device_create_release;
3259 dev_set_name(dev, "%s", name);
3260 dev->groups = attr_grp;
3261 dev_set_drvdata(dev, drvdata);
3263 retval = device_register(dev);
3272 cdev_del(&driver->cdevs[index]);
3273 return ERR_PTR(retval);
3275 EXPORT_SYMBOL_GPL(tty_register_device_attr);
3278 * tty_unregister_device - unregister a tty device
3279 * @driver: the tty driver that describes the tty device
3280 * @index: the index in the tty driver for this tty device
3282 * If a tty device is registered with a call to tty_register_device() then
3283 * this function must be called when the tty device is gone.
3288 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3290 device_destroy(tty_class,
3291 MKDEV(driver->major, driver->minor_start) + index);
3292 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC))
3293 cdev_del(&driver->cdevs[index]);
3295 EXPORT_SYMBOL(tty_unregister_device);
3298 * __tty_alloc_driver -- allocate tty driver
3299 * @lines: count of lines this driver can handle at most
3300 * @owner: module which is repsonsible for this driver
3301 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3303 * This should not be called directly, some of the provided macros should be
3304 * used instead. Use IS_ERR and friends on @retval.
3306 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3307 unsigned long flags)
3309 struct tty_driver *driver;
3310 unsigned int cdevs = 1;
3313 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3314 return ERR_PTR(-EINVAL);
3316 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3318 return ERR_PTR(-ENOMEM);
3320 kref_init(&driver->kref);
3321 driver->magic = TTY_DRIVER_MAGIC;
3322 driver->num = lines;
3323 driver->owner = owner;
3324 driver->flags = flags;
3326 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3327 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3329 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3331 if (!driver->ttys || !driver->termios) {
3337 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3338 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3340 if (!driver->ports) {
3347 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3348 if (!driver->cdevs) {
3355 kfree(driver->ports);
3356 kfree(driver->ttys);
3357 kfree(driver->termios);
3359 return ERR_PTR(err);
3361 EXPORT_SYMBOL(__tty_alloc_driver);
3363 static void destruct_tty_driver(struct kref *kref)
3365 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3367 struct ktermios *tp;
3369 if (driver->flags & TTY_DRIVER_INSTALLED) {
3371 * Free the termios and termios_locked structures because
3372 * we don't want to get memory leaks when modular tty
3373 * drivers are removed from the kernel.
3375 for (i = 0; i < driver->num; i++) {
3376 tp = driver->termios[i];
3378 driver->termios[i] = NULL;
3381 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3382 tty_unregister_device(driver, i);
3384 proc_tty_unregister_driver(driver);
3385 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3386 cdev_del(&driver->cdevs[0]);
3388 kfree(driver->cdevs);
3389 kfree(driver->ports);
3390 kfree(driver->termios);
3391 kfree(driver->ttys);
3395 void tty_driver_kref_put(struct tty_driver *driver)
3397 kref_put(&driver->kref, destruct_tty_driver);
3399 EXPORT_SYMBOL(tty_driver_kref_put);
3401 void tty_set_operations(struct tty_driver *driver,
3402 const struct tty_operations *op)
3406 EXPORT_SYMBOL(tty_set_operations);
3408 void put_tty_driver(struct tty_driver *d)
3410 tty_driver_kref_put(d);
3412 EXPORT_SYMBOL(put_tty_driver);
3415 * Called by a tty driver to register itself.
3417 int tty_register_driver(struct tty_driver *driver)
3424 if (!driver->major) {
3425 error = alloc_chrdev_region(&dev, driver->minor_start,
3426 driver->num, driver->name);
3428 driver->major = MAJOR(dev);
3429 driver->minor_start = MINOR(dev);
3432 dev = MKDEV(driver->major, driver->minor_start);
3433 error = register_chrdev_region(dev, driver->num, driver->name);
3438 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3439 error = tty_cdev_add(driver, dev, 0, driver->num);
3441 goto err_unreg_char;
3444 mutex_lock(&tty_mutex);
3445 list_add(&driver->tty_drivers, &tty_drivers);
3446 mutex_unlock(&tty_mutex);
3448 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3449 for (i = 0; i < driver->num; i++) {
3450 d = tty_register_device(driver, i, NULL);
3453 goto err_unreg_devs;
3457 proc_tty_register_driver(driver);
3458 driver->flags |= TTY_DRIVER_INSTALLED;
3462 for (i--; i >= 0; i--)
3463 tty_unregister_device(driver, i);
3465 mutex_lock(&tty_mutex);
3466 list_del(&driver->tty_drivers);
3467 mutex_unlock(&tty_mutex);
3470 unregister_chrdev_region(dev, driver->num);
3474 EXPORT_SYMBOL(tty_register_driver);
3477 * Called by a tty driver to unregister itself.
3479 int tty_unregister_driver(struct tty_driver *driver)
3483 if (driver->refcount)
3486 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3488 mutex_lock(&tty_mutex);
3489 list_del(&driver->tty_drivers);
3490 mutex_unlock(&tty_mutex);
3494 EXPORT_SYMBOL(tty_unregister_driver);
3496 dev_t tty_devnum(struct tty_struct *tty)
3498 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3500 EXPORT_SYMBOL(tty_devnum);
3502 void tty_default_fops(struct file_operations *fops)
3508 * Initialize the console device. This is called *early*, so
3509 * we can't necessarily depend on lots of kernel help here.
3510 * Just do some early initializations, and do the complex setup
3513 void __init console_init(void)
3517 /* Setup the default TTY line discipline. */
3521 * set up the console device so that later boot sequences can
3522 * inform about problems etc..
3524 call = __con_initcall_start;
3525 while (call < __con_initcall_end) {
3531 static char *tty_devnode(struct device *dev, umode_t *mode)
3535 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3536 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3541 static int __init tty_class_init(void)
3543 tty_class = class_create(THIS_MODULE, "tty");
3544 if (IS_ERR(tty_class))
3545 return PTR_ERR(tty_class);
3546 tty_class->devnode = tty_devnode;
3550 postcore_initcall(tty_class_init);
3552 /* 3/2004 jmc: why do these devices exist? */
3553 static struct cdev tty_cdev, console_cdev;
3555 static ssize_t show_cons_active(struct device *dev,
3556 struct device_attribute *attr, char *buf)
3558 struct console *cs[16];
3564 for_each_console(c) {
3569 if ((c->flags & CON_ENABLED) == 0)
3572 if (i >= ARRAY_SIZE(cs))
3576 int index = cs[i]->index;
3577 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3579 /* don't resolve tty0 as some programs depend on it */
3580 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3581 count += tty_line_name(drv, index, buf + count);
3583 count += sprintf(buf + count, "%s%d",
3584 cs[i]->name, cs[i]->index);
3586 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3592 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3594 static struct attribute *cons_dev_attrs[] = {
3595 &dev_attr_active.attr,
3599 ATTRIBUTE_GROUPS(cons_dev);
3601 static struct device *consdev;
3603 void console_sysfs_notify(void)
3606 sysfs_notify(&consdev->kobj, NULL, "active");
3610 * Ok, now we can initialize the rest of the tty devices and can count
3611 * on memory allocations, interrupts etc..
3613 int __init tty_init(void)
3615 cdev_init(&tty_cdev, &tty_fops);
3616 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3617 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3618 panic("Couldn't register /dev/tty driver\n");
3619 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3621 cdev_init(&console_cdev, &console_fops);
3622 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3623 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3624 panic("Couldn't register /dev/console driver\n");
3625 consdev = device_create_with_groups(tty_class, NULL,
3626 MKDEV(TTYAUX_MAJOR, 1), NULL,
3627 cons_dev_groups, "console");
3628 if (IS_ERR(consdev))
3632 vty_init(&console_fops);