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
238 * @buf: buffer for output
240 * Convert a tty structure into a name. The name reflects the kernel
241 * naming policy and if udev is in use may not reflect user space
246 char *tty_name(struct tty_struct *tty, char *buf)
248 if (!tty) /* Hmm. NULL pointer. That's fun. */
249 strcpy(buf, "NULL tty");
251 strcpy(buf, tty->name);
255 EXPORT_SYMBOL(tty_name);
257 int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
260 #ifdef TTY_PARANOIA_CHECK
263 "null TTY for (%d:%d) in %s\n",
264 imajor(inode), iminor(inode), routine);
267 if (tty->magic != TTY_MAGIC) {
269 "bad magic number for tty struct (%d:%d) in %s\n",
270 imajor(inode), iminor(inode), routine);
277 /* Caller must hold tty_lock */
278 static int check_tty_count(struct tty_struct *tty, const char *routine)
280 #ifdef CHECK_TTY_COUNT
284 spin_lock(&tty_files_lock);
285 list_for_each(p, &tty->tty_files) {
288 spin_unlock(&tty_files_lock);
289 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
290 tty->driver->subtype == PTY_TYPE_SLAVE &&
291 tty->link && tty->link->count)
293 if (tty->count != count) {
294 printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) "
295 "!= #fd's(%d) in %s\n",
296 tty->name, tty->count, count, routine);
304 * get_tty_driver - find device of a tty
305 * @dev_t: device identifier
306 * @index: returns the index of the tty
308 * This routine returns a tty driver structure, given a device number
309 * and also passes back the index number.
311 * Locking: caller must hold tty_mutex
314 static struct tty_driver *get_tty_driver(dev_t device, int *index)
316 struct tty_driver *p;
318 list_for_each_entry(p, &tty_drivers, tty_drivers) {
319 dev_t base = MKDEV(p->major, p->minor_start);
320 if (device < base || device >= base + p->num)
322 *index = device - base;
323 return tty_driver_kref_get(p);
328 #ifdef CONFIG_CONSOLE_POLL
331 * tty_find_polling_driver - find device of a polled tty
332 * @name: name string to match
333 * @line: pointer to resulting tty line nr
335 * This routine returns a tty driver structure, given a name
336 * and the condition that the tty driver is capable of polled
339 struct tty_driver *tty_find_polling_driver(char *name, int *line)
341 struct tty_driver *p, *res = NULL;
346 for (str = name; *str; str++)
347 if ((*str >= '0' && *str <= '9') || *str == ',')
353 tty_line = simple_strtoul(str, &str, 10);
355 mutex_lock(&tty_mutex);
356 /* Search through the tty devices to look for a match */
357 list_for_each_entry(p, &tty_drivers, tty_drivers) {
358 if (strncmp(name, p->name, len) != 0)
366 if (tty_line >= 0 && tty_line < p->num && p->ops &&
367 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
368 res = tty_driver_kref_get(p);
373 mutex_unlock(&tty_mutex);
377 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
381 * tty_check_change - check for POSIX terminal changes
384 * If we try to write to, or set the state of, a terminal and we're
385 * not in the foreground, send a SIGTTOU. If the signal is blocked or
386 * ignored, go ahead and perform the operation. (POSIX 7.2)
391 int tty_check_change(struct tty_struct *tty)
396 if (current->signal->tty != tty)
399 spin_lock_irqsave(&tty->ctrl_lock, flags);
402 printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
405 if (task_pgrp(current) == tty->pgrp)
407 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
408 if (is_ignored(SIGTTOU))
410 if (is_current_pgrp_orphaned()) {
414 kill_pgrp(task_pgrp(current), SIGTTOU, 1);
415 set_thread_flag(TIF_SIGPENDING);
420 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
424 EXPORT_SYMBOL(tty_check_change);
426 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
427 size_t count, loff_t *ppos)
432 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
433 size_t count, loff_t *ppos)
438 /* No kernel lock held - none needed ;) */
439 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
441 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
444 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
447 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
450 static long hung_up_tty_compat_ioctl(struct file *file,
451 unsigned int cmd, unsigned long arg)
453 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
456 static const struct file_operations tty_fops = {
461 .unlocked_ioctl = tty_ioctl,
462 .compat_ioctl = tty_compat_ioctl,
464 .release = tty_release,
465 .fasync = tty_fasync,
468 static const struct file_operations console_fops = {
471 .write = redirected_tty_write,
473 .unlocked_ioctl = tty_ioctl,
474 .compat_ioctl = tty_compat_ioctl,
476 .release = tty_release,
477 .fasync = tty_fasync,
480 static const struct file_operations hung_up_tty_fops = {
482 .read = hung_up_tty_read,
483 .write = hung_up_tty_write,
484 .poll = hung_up_tty_poll,
485 .unlocked_ioctl = hung_up_tty_ioctl,
486 .compat_ioctl = hung_up_tty_compat_ioctl,
487 .release = tty_release,
490 static DEFINE_SPINLOCK(redirect_lock);
491 static struct file *redirect;
494 void proc_clear_tty(struct task_struct *p)
497 struct tty_struct *tty;
498 spin_lock_irqsave(&p->sighand->siglock, flags);
499 tty = p->signal->tty;
500 p->signal->tty = NULL;
501 spin_unlock_irqrestore(&p->sighand->siglock, flags);
506 * proc_set_tty - set the controlling terminal
508 * Only callable by the session leader and only if it does not already have
509 * a controlling terminal.
511 * Caller must hold: tty_lock()
512 * a readlock on tasklist_lock
515 static void __proc_set_tty(struct tty_struct *tty)
519 spin_lock_irqsave(&tty->ctrl_lock, flags);
521 * The session and fg pgrp references will be non-NULL if
522 * tiocsctty() is stealing the controlling tty
524 put_pid(tty->session);
526 tty->pgrp = get_pid(task_pgrp(current));
527 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
528 tty->session = get_pid(task_session(current));
529 if (current->signal->tty) {
530 printk(KERN_DEBUG "tty not NULL!!\n");
531 tty_kref_put(current->signal->tty);
533 put_pid(current->signal->tty_old_pgrp);
534 current->signal->tty = tty_kref_get(tty);
535 current->signal->tty_old_pgrp = NULL;
538 static void proc_set_tty(struct tty_struct *tty)
540 spin_lock_irq(¤t->sighand->siglock);
542 spin_unlock_irq(¤t->sighand->siglock);
545 struct tty_struct *get_current_tty(void)
547 struct tty_struct *tty;
550 spin_lock_irqsave(¤t->sighand->siglock, flags);
551 tty = tty_kref_get(current->signal->tty);
552 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
555 EXPORT_SYMBOL_GPL(get_current_tty);
557 static void session_clear_tty(struct pid *session)
559 struct task_struct *p;
560 do_each_pid_task(session, PIDTYPE_SID, p) {
562 } while_each_pid_task(session, PIDTYPE_SID, p);
566 * tty_wakeup - request more data
569 * Internal and external helper for wakeups of tty. This function
570 * informs the line discipline if present that the driver is ready
571 * to receive more output data.
574 void tty_wakeup(struct tty_struct *tty)
576 struct tty_ldisc *ld;
578 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
579 ld = tty_ldisc_ref(tty);
581 if (ld->ops->write_wakeup)
582 ld->ops->write_wakeup(tty);
586 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
589 EXPORT_SYMBOL_GPL(tty_wakeup);
592 * tty_signal_session_leader - sends SIGHUP to session leader
593 * @tty controlling tty
594 * @exit_session if non-zero, signal all foreground group processes
596 * Send SIGHUP and SIGCONT to the session leader and its process group.
597 * Optionally, signal all processes in the foreground process group.
599 * Returns the number of processes in the session with this tty
600 * as their controlling terminal. This value is used to drop
601 * tty references for those processes.
603 static int tty_signal_session_leader(struct tty_struct *tty, int exit_session)
605 struct task_struct *p;
607 struct pid *tty_pgrp = NULL;
609 read_lock(&tasklist_lock);
611 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
612 spin_lock_irq(&p->sighand->siglock);
613 if (p->signal->tty == tty) {
614 p->signal->tty = NULL;
615 /* We defer the dereferences outside fo
619 if (!p->signal->leader) {
620 spin_unlock_irq(&p->sighand->siglock);
623 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
624 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
625 put_pid(p->signal->tty_old_pgrp); /* A noop */
626 spin_lock(&tty->ctrl_lock);
627 tty_pgrp = get_pid(tty->pgrp);
629 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
630 spin_unlock(&tty->ctrl_lock);
631 spin_unlock_irq(&p->sighand->siglock);
632 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
634 read_unlock(&tasklist_lock);
638 kill_pgrp(tty_pgrp, SIGHUP, exit_session);
646 * __tty_hangup - actual handler for hangup events
649 * This can be called by a "kworker" kernel thread. That is process
650 * synchronous but doesn't hold any locks, so we need to make sure we
651 * have the appropriate locks for what we're doing.
653 * The hangup event clears any pending redirections onto the hung up
654 * device. It ensures future writes will error and it does the needed
655 * line discipline hangup and signal delivery. The tty object itself
660 * redirect lock for undoing redirection
661 * file list lock for manipulating list of ttys
662 * tty_ldiscs_lock from called functions
663 * termios_rwsem resetting termios data
664 * tasklist_lock to walk task list for hangup event
665 * ->siglock to protect ->signal/->sighand
667 static void __tty_hangup(struct tty_struct *tty, int exit_session)
669 struct file *cons_filp = NULL;
670 struct file *filp, *f = NULL;
671 struct tty_file_private *priv;
672 int closecount = 0, n;
679 spin_lock(&redirect_lock);
680 if (redirect && file_tty(redirect) == tty) {
684 spin_unlock(&redirect_lock);
688 if (test_bit(TTY_HUPPED, &tty->flags)) {
693 /* inuse_filps is protected by the single tty lock,
694 this really needs to change if we want to flush the
695 workqueue with the lock held */
696 check_tty_count(tty, "tty_hangup");
698 spin_lock(&tty_files_lock);
699 /* This breaks for file handles being sent over AF_UNIX sockets ? */
700 list_for_each_entry(priv, &tty->tty_files, list) {
702 if (filp->f_op->write == redirected_tty_write)
704 if (filp->f_op->write != tty_write)
707 __tty_fasync(-1, filp, 0); /* can't block */
708 filp->f_op = &hung_up_tty_fops;
710 spin_unlock(&tty_files_lock);
712 refs = tty_signal_session_leader(tty, exit_session);
713 /* Account for the p->signal references we killed */
717 tty_ldisc_hangup(tty);
719 spin_lock_irq(&tty->ctrl_lock);
720 clear_bit(TTY_THROTTLED, &tty->flags);
721 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
722 put_pid(tty->session);
726 tty->ctrl_status = 0;
727 spin_unlock_irq(&tty->ctrl_lock);
730 * If one of the devices matches a console pointer, we
731 * cannot just call hangup() because that will cause
732 * tty->count and state->count to go out of sync.
733 * So we just call close() the right number of times.
737 for (n = 0; n < closecount; n++)
738 tty->ops->close(tty, cons_filp);
739 } else if (tty->ops->hangup)
740 tty->ops->hangup(tty);
742 * We don't want to have driver/ldisc interactions beyond
743 * the ones we did here. The driver layer expects no
744 * calls after ->hangup() from the ldisc side. However we
745 * can't yet guarantee all that.
747 set_bit(TTY_HUPPED, &tty->flags);
754 static void do_tty_hangup(struct work_struct *work)
756 struct tty_struct *tty =
757 container_of(work, struct tty_struct, hangup_work);
759 __tty_hangup(tty, 0);
763 * tty_hangup - trigger a hangup event
764 * @tty: tty to hangup
766 * A carrier loss (virtual or otherwise) has occurred on this like
767 * schedule a hangup sequence to run after this event.
770 void tty_hangup(struct tty_struct *tty)
772 #ifdef TTY_DEBUG_HANGUP
774 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
776 schedule_work(&tty->hangup_work);
779 EXPORT_SYMBOL(tty_hangup);
782 * tty_vhangup - process vhangup
783 * @tty: tty to hangup
785 * The user has asked via system call for the terminal to be hung up.
786 * We do this synchronously so that when the syscall returns the process
787 * is complete. That guarantee is necessary for security reasons.
790 void tty_vhangup(struct tty_struct *tty)
792 #ifdef TTY_DEBUG_HANGUP
795 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
797 __tty_hangup(tty, 0);
800 EXPORT_SYMBOL(tty_vhangup);
804 * tty_vhangup_self - process vhangup for own ctty
806 * Perform a vhangup on the current controlling tty
809 void tty_vhangup_self(void)
811 struct tty_struct *tty;
813 tty = get_current_tty();
821 * tty_vhangup_session - hangup session leader exit
822 * @tty: tty to hangup
824 * The session leader is exiting and hanging up its controlling terminal.
825 * Every process in the foreground process group is signalled SIGHUP.
827 * We do this synchronously so that when the syscall returns the process
828 * is complete. That guarantee is necessary for security reasons.
831 static void tty_vhangup_session(struct tty_struct *tty)
833 #ifdef TTY_DEBUG_HANGUP
836 printk(KERN_DEBUG "%s vhangup session...\n", tty_name(tty, buf));
838 __tty_hangup(tty, 1);
842 * tty_hung_up_p - was tty hung up
843 * @filp: file pointer of tty
845 * Return true if the tty has been subject to a vhangup or a carrier
849 int tty_hung_up_p(struct file *filp)
851 return (filp->f_op == &hung_up_tty_fops);
854 EXPORT_SYMBOL(tty_hung_up_p);
857 * disassociate_ctty - disconnect controlling tty
858 * @on_exit: true if exiting so need to "hang up" the session
860 * This function is typically called only by the session leader, when
861 * it wants to disassociate itself from its controlling tty.
863 * It performs the following functions:
864 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
865 * (2) Clears the tty from being controlling the session
866 * (3) Clears the controlling tty for all processes in the
869 * The argument on_exit is set to 1 if called when a process is
870 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
873 * BTM is taken for hysterical raisins, and held when
874 * called from no_tty().
875 * tty_mutex is taken to protect tty
876 * ->siglock is taken to protect ->signal/->sighand
877 * tasklist_lock is taken to walk process list for sessions
878 * ->siglock is taken to protect ->signal/->sighand
881 void disassociate_ctty(int on_exit)
883 struct tty_struct *tty;
885 if (!current->signal->leader)
888 tty = get_current_tty();
890 if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) {
891 tty_vhangup_session(tty);
893 struct pid *tty_pgrp = tty_get_pgrp(tty);
895 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
897 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
903 } else if (on_exit) {
904 struct pid *old_pgrp;
905 spin_lock_irq(¤t->sighand->siglock);
906 old_pgrp = current->signal->tty_old_pgrp;
907 current->signal->tty_old_pgrp = NULL;
908 spin_unlock_irq(¤t->sighand->siglock);
910 kill_pgrp(old_pgrp, SIGHUP, on_exit);
911 kill_pgrp(old_pgrp, SIGCONT, on_exit);
917 spin_lock_irq(¤t->sighand->siglock);
918 put_pid(current->signal->tty_old_pgrp);
919 current->signal->tty_old_pgrp = NULL;
921 tty = tty_kref_get(current->signal->tty);
924 spin_lock_irqsave(&tty->ctrl_lock, flags);
925 put_pid(tty->session);
929 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
932 #ifdef TTY_DEBUG_HANGUP
933 printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
938 spin_unlock_irq(¤t->sighand->siglock);
939 /* Now clear signal->tty under the lock */
940 read_lock(&tasklist_lock);
941 session_clear_tty(task_session(current));
942 read_unlock(&tasklist_lock);
947 * no_tty - Ensure the current process does not have a controlling tty
951 /* FIXME: Review locking here. The tty_lock never covered any race
952 between a new association and proc_clear_tty but possible we need
953 to protect against this anyway */
954 struct task_struct *tsk = current;
955 disassociate_ctty(0);
961 * stop_tty - propagate flow control
964 * Perform flow control to the driver. May be called
965 * on an already stopped device and will not re-call the driver
968 * This functionality is used by both the line disciplines for
969 * halting incoming flow and by the driver. It may therefore be
970 * called from any context, may be under the tty atomic_write_lock
977 void __stop_tty(struct tty_struct *tty)
986 void stop_tty(struct tty_struct *tty)
990 spin_lock_irqsave(&tty->flow_lock, flags);
992 spin_unlock_irqrestore(&tty->flow_lock, flags);
994 EXPORT_SYMBOL(stop_tty);
997 * start_tty - propagate flow control
1000 * Start a tty that has been stopped if at all possible. If this
1001 * tty was previous stopped and is now being started, the driver
1002 * start method is invoked and the line discipline woken.
1008 void __start_tty(struct tty_struct *tty)
1010 if (!tty->stopped || tty->flow_stopped)
1013 if (tty->ops->start)
1014 tty->ops->start(tty);
1018 void start_tty(struct tty_struct *tty)
1020 unsigned long flags;
1022 spin_lock_irqsave(&tty->flow_lock, flags);
1024 spin_unlock_irqrestore(&tty->flow_lock, flags);
1026 EXPORT_SYMBOL(start_tty);
1028 static void tty_update_time(struct timespec *time)
1030 unsigned long sec = get_seconds();
1033 * We only care if the two values differ in anything other than the
1034 * lower three bits (i.e every 8 seconds). If so, then we can update
1035 * the time of the tty device, otherwise it could be construded as a
1036 * security leak to let userspace know the exact timing of the tty.
1038 if ((sec ^ time->tv_sec) & ~7)
1043 * tty_read - read method for tty device files
1044 * @file: pointer to tty file
1046 * @count: size of user buffer
1049 * Perform the read system call function on this terminal device. Checks
1050 * for hung up devices before calling the line discipline method.
1053 * Locks the line discipline internally while needed. Multiple
1054 * read calls may be outstanding in parallel.
1057 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
1061 struct inode *inode = file_inode(file);
1062 struct tty_struct *tty = file_tty(file);
1063 struct tty_ldisc *ld;
1065 if (tty_paranoia_check(tty, inode, "tty_read"))
1067 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
1070 /* We want to wait for the line discipline to sort out in this
1072 ld = tty_ldisc_ref_wait(tty);
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) {
1208 tty->ops->write(tty, msg, strlen(msg));
1211 tty_write_unlock(tty);
1218 * tty_write - write method for tty device file
1219 * @file: tty file pointer
1220 * @buf: user data to write
1221 * @count: bytes to write
1224 * Write data to a tty device via the line discipline.
1227 * Locks the line discipline as required
1228 * Writes to the tty driver are serialized by the atomic_write_lock
1229 * and are then processed in chunks to the device. The line discipline
1230 * write method will not be invoked in parallel for each device.
1233 static ssize_t tty_write(struct file *file, const char __user *buf,
1234 size_t count, loff_t *ppos)
1236 struct tty_struct *tty = file_tty(file);
1237 struct tty_ldisc *ld;
1240 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1242 if (!tty || !tty->ops->write ||
1243 (test_bit(TTY_IO_ERROR, &tty->flags)))
1245 /* Short term debug to catch buggy drivers */
1246 if (tty->ops->write_room == NULL)
1247 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1249 ld = tty_ldisc_ref_wait(tty);
1250 if (!ld->ops->write)
1253 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1254 tty_ldisc_deref(ld);
1258 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1259 size_t count, loff_t *ppos)
1261 struct file *p = NULL;
1263 spin_lock(&redirect_lock);
1265 p = get_file(redirect);
1266 spin_unlock(&redirect_lock);
1270 res = vfs_write(p, buf, count, &p->f_pos);
1274 return tty_write(file, buf, count, ppos);
1278 * tty_send_xchar - send priority character
1280 * Send a high priority character to the tty even if stopped
1282 * Locking: none for xchar method, write ordering for write method.
1285 int tty_send_xchar(struct tty_struct *tty, char ch)
1287 int was_stopped = tty->stopped;
1289 if (tty->ops->send_xchar) {
1290 tty->ops->send_xchar(tty, ch);
1294 if (tty_write_lock(tty, 0) < 0)
1295 return -ERESTARTSYS;
1299 tty->ops->write(tty, &ch, 1);
1302 tty_write_unlock(tty);
1306 static char ptychar[] = "pqrstuvwxyzabcde";
1309 * pty_line_name - generate name for a pty
1310 * @driver: the tty driver in use
1311 * @index: the minor number
1312 * @p: output buffer of at least 6 bytes
1314 * Generate a name from a driver reference and write it to the output
1319 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1321 int i = index + driver->name_base;
1322 /* ->name is initialized to "ttyp", but "tty" is expected */
1323 sprintf(p, "%s%c%x",
1324 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1325 ptychar[i >> 4 & 0xf], i & 0xf);
1329 * tty_line_name - generate name for a tty
1330 * @driver: the tty driver in use
1331 * @index: the minor number
1332 * @p: output buffer of at least 7 bytes
1334 * Generate a name from a driver reference and write it to the output
1339 static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1341 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1342 return sprintf(p, "%s", driver->name);
1344 return sprintf(p, "%s%d", driver->name,
1345 index + driver->name_base);
1349 * tty_driver_lookup_tty() - find an existing tty, if any
1350 * @driver: the driver for the tty
1351 * @idx: the minor number
1353 * Return the tty, if found. If not found, return NULL or ERR_PTR() if the
1354 * driver lookup() method returns an error.
1356 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1358 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1359 struct inode *inode, int idx)
1361 struct tty_struct *tty;
1363 if (driver->ops->lookup)
1364 tty = driver->ops->lookup(driver, inode, idx);
1366 tty = driver->ttys[idx];
1374 * tty_init_termios - helper for termios setup
1375 * @tty: the tty to set up
1377 * Initialise the termios structures for this tty. Thus runs under
1378 * the tty_mutex currently so we can be relaxed about ordering.
1381 int tty_init_termios(struct tty_struct *tty)
1383 struct ktermios *tp;
1384 int idx = tty->index;
1386 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1387 tty->termios = tty->driver->init_termios;
1389 /* Check for lazy saved data */
1390 tp = tty->driver->termios[idx];
1394 tty->termios = tty->driver->init_termios;
1396 /* Compatibility until drivers always set this */
1397 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1398 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1401 EXPORT_SYMBOL_GPL(tty_init_termios);
1403 int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1405 int ret = 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 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;
1469 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1470 driver->subtype == PTY_TYPE_MASTER)
1473 if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
1478 WARN_ON(!tty->ldisc);
1484 * tty_init_dev - initialise a tty device
1485 * @driver: tty driver we are opening a device on
1486 * @idx: device index
1487 * @ret_tty: returned tty structure
1489 * Prepare a tty device. This may not be a "new" clean device but
1490 * could also be an active device. The pty drivers require special
1491 * handling because of this.
1494 * The function is called under the tty_mutex, which
1495 * protects us from the tty struct or driver itself going away.
1497 * On exit the tty device has the line discipline attached and
1498 * a reference count of 1. If a pair was created for pty/tty use
1499 * and the other was a pty master then it too has a reference count of 1.
1501 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1502 * failed open. The new code protects the open with a mutex, so it's
1503 * really quite straightforward. The mutex locking can probably be
1504 * relaxed for the (most common) case of reopening a tty.
1507 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1509 struct tty_struct *tty;
1513 * First time open is complex, especially for PTY devices.
1514 * This code guarantees that either everything succeeds and the
1515 * TTY is ready for operation, or else the table slots are vacated
1516 * and the allocated memory released. (Except that the termios
1517 * and locked termios may be retained.)
1520 if (!try_module_get(driver->owner))
1521 return ERR_PTR(-ENODEV);
1523 tty = alloc_tty_struct(driver, idx);
1526 goto err_module_put;
1530 retval = tty_driver_install_tty(driver, tty);
1532 goto err_deinit_tty;
1535 tty->port = driver->ports[idx];
1537 WARN_RATELIMIT(!tty->port,
1538 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1539 __func__, tty->driver->name);
1541 tty->port->itty = tty;
1544 * Structures all installed ... call the ldisc open routines.
1545 * If we fail here just call release_tty to clean up. No need
1546 * to decrement the use counts, as release_tty doesn't care.
1548 retval = tty_ldisc_setup(tty, tty->link);
1550 goto err_release_tty;
1551 /* Return the tty locked so that it cannot vanish under the caller */
1556 deinitialize_tty_struct(tty);
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 printk_ratelimited(KERN_INFO "tty_init_dev: ldisc open failed, "
1566 "clearing slot %d\n", idx);
1567 release_tty(tty, idx);
1568 return ERR_PTR(retval);
1571 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);
1585 pr_warn("tty: no memory to save termios state.\n");
1588 tty->driver->termios[idx] = tp;
1592 EXPORT_SYMBOL(tty_free_termios);
1595 * tty_flush_works - flush all works of a tty/pty pair
1596 * @tty: tty device to flush works for (or either end of a pty pair)
1598 * Sync flush all works belonging to @tty (and the 'other' tty).
1600 static void tty_flush_works(struct tty_struct *tty)
1602 flush_work(&tty->SAK_work);
1603 flush_work(&tty->hangup_work);
1605 flush_work(&tty->link->SAK_work);
1606 flush_work(&tty->link->hangup_work);
1611 * release_one_tty - release tty structure memory
1612 * @kref: kref of tty we are obliterating
1614 * Releases memory associated with a tty structure, and clears out the
1615 * driver table slots. This function is called when a device is no longer
1616 * in use. It also gets called when setup of a device fails.
1619 * takes the file list lock internally when working on the list
1620 * of ttys that the driver keeps.
1622 * This method gets called from a work queue so that the driver private
1623 * cleanup ops can sleep (needed for USB at least)
1625 static void release_one_tty(struct work_struct *work)
1627 struct tty_struct *tty =
1628 container_of(work, struct tty_struct, hangup_work);
1629 struct tty_driver *driver = tty->driver;
1630 struct module *owner = driver->owner;
1632 if (tty->ops->cleanup)
1633 tty->ops->cleanup(tty);
1636 tty_driver_kref_put(driver);
1639 spin_lock(&tty_files_lock);
1640 list_del_init(&tty->tty_files);
1641 spin_unlock(&tty_files_lock);
1644 put_pid(tty->session);
1645 free_tty_struct(tty);
1648 static void queue_release_one_tty(struct kref *kref)
1650 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1652 /* The hangup queue is now free so we can reuse it rather than
1653 waste a chunk of memory for each port */
1654 INIT_WORK(&tty->hangup_work, release_one_tty);
1655 schedule_work(&tty->hangup_work);
1659 * tty_kref_put - release a tty kref
1662 * Release a reference to a tty device and if need be let the kref
1663 * layer destruct the object for us
1666 void tty_kref_put(struct tty_struct *tty)
1669 kref_put(&tty->kref, queue_release_one_tty);
1671 EXPORT_SYMBOL(tty_kref_put);
1674 * release_tty - release tty structure memory
1676 * Release both @tty and a possible linked partner (think pty pair),
1677 * and decrement the refcount of the backing module.
1681 * takes the file list lock internally when working on the list
1682 * of ttys that the driver keeps.
1685 static void release_tty(struct tty_struct *tty, int idx)
1687 /* This should always be true but check for the moment */
1688 WARN_ON(tty->index != idx);
1689 WARN_ON(!mutex_is_locked(&tty_mutex));
1690 if (tty->ops->shutdown)
1691 tty->ops->shutdown(tty);
1692 tty_free_termios(tty);
1693 tty_driver_remove_tty(tty->driver, tty);
1694 tty->port->itty = NULL;
1696 tty->link->port->itty = NULL;
1697 cancel_work_sync(&tty->port->buf.work);
1699 tty_kref_put(tty->link);
1704 * tty_release_checks - check a tty before real release
1705 * @tty: tty to check
1706 * @o_tty: link of @tty (if any)
1707 * @idx: index of the tty
1709 * Performs some paranoid checking before true release of the @tty.
1710 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1712 static int tty_release_checks(struct tty_struct *tty, int idx)
1714 #ifdef TTY_PARANOIA_CHECK
1715 if (idx < 0 || idx >= tty->driver->num) {
1716 printk(KERN_DEBUG "%s: bad idx when trying to free (%s)\n",
1717 __func__, tty->name);
1721 /* not much to check for devpts */
1722 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1725 if (tty != tty->driver->ttys[idx]) {
1726 printk(KERN_DEBUG "%s: driver.table[%d] not tty for (%s)\n",
1727 __func__, idx, tty->name);
1730 if (tty->driver->other) {
1731 struct tty_struct *o_tty = tty->link;
1733 if (o_tty != tty->driver->other->ttys[idx]) {
1734 printk(KERN_DEBUG "%s: other->table[%d] not o_tty for (%s)\n",
1735 __func__, idx, tty->name);
1738 if (o_tty->link != tty) {
1739 printk(KERN_DEBUG "%s: bad pty pointers\n", __func__);
1748 * tty_release - vfs callback for close
1749 * @inode: inode of tty
1750 * @filp: file pointer for handle to tty
1752 * Called the last time each file handle is closed that references
1753 * this tty. There may however be several such references.
1756 * Takes bkl. See tty_release_dev
1758 * Even releasing the tty structures is a tricky business.. We have
1759 * to be very careful that the structures are all released at the
1760 * same time, as interrupts might otherwise get the wrong pointers.
1762 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1763 * lead to double frees or releasing memory still in use.
1766 int tty_release(struct inode *inode, struct file *filp)
1768 struct tty_struct *tty = file_tty(filp);
1769 struct tty_struct *o_tty = NULL;
1770 int do_sleep, final;
1776 if (tty_paranoia_check(tty, inode, __func__))
1780 check_tty_count(tty, __func__);
1782 __tty_fasync(-1, filp, 0);
1785 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1786 tty->driver->subtype == PTY_TYPE_MASTER)
1789 if (tty_release_checks(tty, idx)) {
1794 #ifdef TTY_DEBUG_HANGUP
1795 printk(KERN_DEBUG "%s: %s (tty count=%d)...\n", __func__,
1796 tty_name(tty, buf), tty->count);
1799 if (tty->ops->close)
1800 tty->ops->close(tty, filp);
1802 /* If tty is pty master, lock the slave pty (stable lock order) */
1803 tty_lock_slave(o_tty);
1806 * Sanity check: if tty->count is going to zero, there shouldn't be
1807 * any waiters on tty->read_wait or tty->write_wait. We test the
1808 * wait queues and kick everyone out _before_ actually starting to
1809 * close. This ensures that we won't block while releasing the tty
1812 * The test for the o_tty closing is necessary, since the master and
1813 * slave sides may close in any order. If the slave side closes out
1814 * first, its count will be one, since the master side holds an open.
1815 * Thus this test wouldn't be triggered at the time the slave closed,
1821 if (tty->count <= 1) {
1822 if (waitqueue_active(&tty->read_wait)) {
1823 wake_up_poll(&tty->read_wait, POLLIN);
1826 if (waitqueue_active(&tty->write_wait)) {
1827 wake_up_poll(&tty->write_wait, POLLOUT);
1831 if (o_tty && o_tty->count <= 1) {
1832 if (waitqueue_active(&o_tty->read_wait)) {
1833 wake_up_poll(&o_tty->read_wait, POLLIN);
1836 if (waitqueue_active(&o_tty->write_wait)) {
1837 wake_up_poll(&o_tty->write_wait, POLLOUT);
1846 printk(KERN_WARNING "%s: %s: read/write wait queue active!\n",
1847 __func__, tty_name(tty, buf));
1849 schedule_timeout_killable(timeout);
1850 if (timeout < 120 * HZ)
1851 timeout = 2 * timeout + 1;
1853 timeout = MAX_SCHEDULE_TIMEOUT;
1857 if (--o_tty->count < 0) {
1858 printk(KERN_WARNING "%s: bad pty slave count (%d) for %s\n",
1859 __func__, o_tty->count, tty_name(o_tty, buf));
1863 if (--tty->count < 0) {
1864 printk(KERN_WARNING "%s: bad tty->count (%d) for %s\n",
1865 __func__, tty->count, tty_name(tty, buf));
1870 * We've decremented tty->count, so we need to remove this file
1871 * descriptor off the tty->tty_files list; this serves two
1873 * - check_tty_count sees the correct number of file descriptors
1874 * associated with this tty.
1875 * - do_tty_hangup no longer sees this file descriptor as
1876 * something that needs to be handled for hangups.
1881 * Perform some housekeeping before deciding whether to return.
1883 * If _either_ side is closing, make sure there aren't any
1884 * processes that still think tty or o_tty is their controlling
1888 read_lock(&tasklist_lock);
1889 session_clear_tty(tty->session);
1891 session_clear_tty(o_tty->session);
1892 read_unlock(&tasklist_lock);
1895 /* check whether both sides are closing ... */
1896 final = !tty->count && !(o_tty && o_tty->count);
1898 tty_unlock_slave(o_tty);
1901 /* At this point, the tty->count == 0 should ensure a dead tty
1902 cannot be re-opened by a racing opener */
1907 #ifdef TTY_DEBUG_HANGUP
1908 printk(KERN_DEBUG "%s: %s: final close\n", __func__, tty_name(tty, buf));
1911 * Ask the line discipline code to release its structures
1913 tty_ldisc_release(tty);
1915 /* Wait for pending work before tty destruction commmences */
1916 tty_flush_works(tty);
1918 #ifdef TTY_DEBUG_HANGUP
1919 printk(KERN_DEBUG "%s: %s: freeing structure...\n", __func__, tty_name(tty, buf));
1922 * The release_tty function takes care of the details of clearing
1923 * the slots and preserving the termios structure. The tty_unlock_pair
1924 * should be safe as we keep a kref while the tty is locked (so the
1925 * unlock never unlocks a freed tty).
1927 mutex_lock(&tty_mutex);
1928 release_tty(tty, idx);
1929 mutex_unlock(&tty_mutex);
1935 * tty_open_current_tty - get locked tty of current task
1936 * @device: device number
1937 * @filp: file pointer to tty
1938 * @return: locked tty of the current task iff @device is /dev/tty
1940 * Performs a re-open of the current task's controlling tty.
1942 * We cannot return driver and index like for the other nodes because
1943 * devpts will not work then. It expects inodes to be from devpts FS.
1945 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1947 struct tty_struct *tty;
1950 if (device != MKDEV(TTYAUX_MAJOR, 0))
1953 tty = get_current_tty();
1955 return ERR_PTR(-ENXIO);
1957 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1960 tty_kref_put(tty); /* safe to drop the kref now */
1962 retval = tty_reopen(tty);
1965 tty = ERR_PTR(retval);
1971 * tty_lookup_driver - lookup a tty driver for a given device file
1972 * @device: device number
1973 * @filp: file pointer to tty
1974 * @noctty: set if the device should not become a controlling tty
1975 * @index: index for the device in the @return driver
1976 * @return: driver for this inode (with increased refcount)
1978 * If @return is not erroneous, the caller is responsible to decrement the
1979 * refcount by tty_driver_kref_put.
1981 * Locking: tty_mutex protects get_tty_driver
1983 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1984 int *noctty, int *index)
1986 struct tty_driver *driver;
1990 case MKDEV(TTY_MAJOR, 0): {
1991 extern struct tty_driver *console_driver;
1992 driver = tty_driver_kref_get(console_driver);
1993 *index = fg_console;
1998 case MKDEV(TTYAUX_MAJOR, 1): {
1999 struct tty_driver *console_driver = console_device(index);
2000 if (console_driver) {
2001 driver = tty_driver_kref_get(console_driver);
2003 /* Don't let /dev/console block */
2004 filp->f_flags |= O_NONBLOCK;
2009 return ERR_PTR(-ENODEV);
2012 driver = get_tty_driver(device, index);
2014 return ERR_PTR(-ENODEV);
2021 * tty_open - open a tty device
2022 * @inode: inode of device file
2023 * @filp: file pointer to tty
2025 * tty_open and tty_release keep up the tty count that contains the
2026 * number of opens done on a tty. We cannot use the inode-count, as
2027 * different inodes might point to the same tty.
2029 * Open-counting is needed for pty masters, as well as for keeping
2030 * track of serial lines: DTR is dropped when the last close happens.
2031 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2033 * The termios state of a pty is reset on first open so that
2034 * settings don't persist across reuse.
2036 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
2037 * tty->count should protect the rest.
2038 * ->siglock protects ->signal/->sighand
2040 * Note: the tty_unlock/lock cases without a ref are only safe due to
2044 static int tty_open(struct inode *inode, struct file *filp)
2046 struct tty_struct *tty;
2048 struct tty_driver *driver = NULL;
2050 dev_t device = inode->i_rdev;
2051 unsigned saved_flags = filp->f_flags;
2053 nonseekable_open(inode, filp);
2056 retval = tty_alloc_file(filp);
2060 noctty = filp->f_flags & O_NOCTTY;
2064 tty = tty_open_current_tty(device, filp);
2066 mutex_lock(&tty_mutex);
2067 driver = tty_lookup_driver(device, filp, &noctty, &index);
2068 if (IS_ERR(driver)) {
2069 retval = PTR_ERR(driver);
2073 /* check whether we're reopening an existing tty */
2074 tty = tty_driver_lookup_tty(driver, inode, index);
2076 retval = PTR_ERR(tty);
2081 mutex_unlock(&tty_mutex);
2083 /* safe to drop the kref from tty_driver_lookup_tty() */
2085 retval = tty_reopen(tty);
2088 tty = ERR_PTR(retval);
2090 } else { /* Returns with the tty_lock held for now */
2091 tty = tty_init_dev(driver, index);
2092 mutex_unlock(&tty_mutex);
2095 tty_driver_kref_put(driver);
2099 retval = PTR_ERR(tty);
2103 tty_add_file(tty, filp);
2105 check_tty_count(tty, __func__);
2106 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2107 tty->driver->subtype == PTY_TYPE_MASTER)
2109 #ifdef TTY_DEBUG_HANGUP
2110 printk(KERN_DEBUG "%s: opening %s...\n", __func__, tty->name);
2113 retval = tty->ops->open(tty, filp);
2116 filp->f_flags = saved_flags;
2119 #ifdef TTY_DEBUG_HANGUP
2120 printk(KERN_DEBUG "%s: error %d in opening %s...\n", __func__,
2123 tty_unlock(tty); /* need to call tty_release without BTM */
2124 tty_release(inode, filp);
2125 if (retval != -ERESTARTSYS)
2128 if (signal_pending(current))
2133 * Need to reset f_op in case a hangup happened.
2135 if (tty_hung_up_p(filp))
2136 filp->f_op = &tty_fops;
2139 clear_bit(TTY_HUPPED, &tty->flags);
2142 read_lock(&tasklist_lock);
2143 spin_lock_irq(¤t->sighand->siglock);
2145 current->signal->leader &&
2146 !current->signal->tty &&
2147 tty->session == NULL)
2148 __proc_set_tty(tty);
2149 spin_unlock_irq(¤t->sighand->siglock);
2150 read_unlock(&tasklist_lock);
2154 mutex_unlock(&tty_mutex);
2155 /* after locks to avoid deadlock */
2156 if (!IS_ERR_OR_NULL(driver))
2157 tty_driver_kref_put(driver);
2159 tty_free_file(filp);
2166 * tty_poll - check tty status
2167 * @filp: file being polled
2168 * @wait: poll wait structures to update
2170 * Call the line discipline polling method to obtain the poll
2171 * status of the device.
2173 * Locking: locks called line discipline but ldisc poll method
2174 * may be re-entered freely by other callers.
2177 static unsigned int tty_poll(struct file *filp, poll_table *wait)
2179 struct tty_struct *tty = file_tty(filp);
2180 struct tty_ldisc *ld;
2183 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2186 ld = tty_ldisc_ref_wait(tty);
2188 ret = ld->ops->poll(tty, filp, wait);
2189 tty_ldisc_deref(ld);
2193 static int __tty_fasync(int fd, struct file *filp, int on)
2195 struct tty_struct *tty = file_tty(filp);
2196 struct tty_ldisc *ldisc;
2197 unsigned long flags;
2200 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2203 retval = fasync_helper(fd, filp, on, &tty->fasync);
2207 ldisc = tty_ldisc_ref(tty);
2209 if (ldisc->ops->fasync)
2210 ldisc->ops->fasync(tty, on);
2211 tty_ldisc_deref(ldisc);
2218 spin_lock_irqsave(&tty->ctrl_lock, flags);
2221 type = PIDTYPE_PGID;
2223 pid = task_pid(current);
2227 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2228 __f_setown(filp, pid, type, 0);
2236 static int tty_fasync(int fd, struct file *filp, int on)
2238 struct tty_struct *tty = file_tty(filp);
2242 retval = __tty_fasync(fd, filp, on);
2249 * tiocsti - fake input character
2250 * @tty: tty to fake input into
2251 * @p: pointer to character
2253 * Fake input to a tty device. Does the necessary locking and
2256 * FIXME: does not honour flow control ??
2259 * Called functions take tty_ldiscs_lock
2260 * current->signal->tty check is safe without locks
2262 * FIXME: may race normal receive processing
2265 static int tiocsti(struct tty_struct *tty, char __user *p)
2268 struct tty_ldisc *ld;
2270 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2272 if (get_user(ch, p))
2274 tty_audit_tiocsti(tty, ch);
2275 ld = tty_ldisc_ref_wait(tty);
2276 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2277 tty_ldisc_deref(ld);
2282 * tiocgwinsz - implement window query ioctl
2284 * @arg: user buffer for result
2286 * Copies the kernel idea of the window size into the user buffer.
2288 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2292 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2296 mutex_lock(&tty->winsize_mutex);
2297 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2298 mutex_unlock(&tty->winsize_mutex);
2300 return err ? -EFAULT: 0;
2304 * tty_do_resize - resize event
2305 * @tty: tty being resized
2306 * @rows: rows (character)
2307 * @cols: cols (character)
2309 * Update the termios variables and send the necessary signals to
2310 * peform a terminal resize correctly
2313 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2318 mutex_lock(&tty->winsize_mutex);
2319 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2322 /* Signal the foreground process group */
2323 pgrp = tty_get_pgrp(tty);
2325 kill_pgrp(pgrp, SIGWINCH, 1);
2330 mutex_unlock(&tty->winsize_mutex);
2333 EXPORT_SYMBOL(tty_do_resize);
2336 * tiocswinsz - implement window size set ioctl
2337 * @tty; tty side of tty
2338 * @arg: user buffer for result
2340 * Copies the user idea of the window size to the kernel. Traditionally
2341 * this is just advisory information but for the Linux console it
2342 * actually has driver level meaning and triggers a VC resize.
2345 * Driver dependent. The default do_resize method takes the
2346 * tty termios mutex and ctrl_lock. The console takes its own lock
2347 * then calls into the default method.
2350 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2352 struct winsize tmp_ws;
2353 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2356 if (tty->ops->resize)
2357 return tty->ops->resize(tty, &tmp_ws);
2359 return tty_do_resize(tty, &tmp_ws);
2363 * tioccons - allow admin to move logical console
2364 * @file: the file to become console
2366 * Allow the administrator to move the redirected console device
2368 * Locking: uses redirect_lock to guard the redirect information
2371 static int tioccons(struct file *file)
2373 if (!capable(CAP_SYS_ADMIN))
2375 if (file->f_op->write == redirected_tty_write) {
2377 spin_lock(&redirect_lock);
2380 spin_unlock(&redirect_lock);
2385 spin_lock(&redirect_lock);
2387 spin_unlock(&redirect_lock);
2390 redirect = get_file(file);
2391 spin_unlock(&redirect_lock);
2396 * fionbio - non blocking ioctl
2397 * @file: file to set blocking value
2398 * @p: user parameter
2400 * Historical tty interfaces had a blocking control ioctl before
2401 * the generic functionality existed. This piece of history is preserved
2402 * in the expected tty API of posix OS's.
2404 * Locking: none, the open file handle ensures it won't go away.
2407 static int fionbio(struct file *file, int __user *p)
2411 if (get_user(nonblock, p))
2414 spin_lock(&file->f_lock);
2416 file->f_flags |= O_NONBLOCK;
2418 file->f_flags &= ~O_NONBLOCK;
2419 spin_unlock(&file->f_lock);
2424 * tiocsctty - set controlling tty
2425 * @tty: tty structure
2426 * @arg: user argument
2428 * This ioctl is used to manage job control. It permits a session
2429 * leader to set this tty as the controlling tty for the session.
2432 * Takes tty_lock() to serialize proc_set_tty() for this tty
2433 * Takes tasklist_lock internally to walk sessions
2434 * Takes ->siglock() when updating signal->tty
2437 static int tiocsctty(struct tty_struct *tty, int arg)
2442 read_lock(&tasklist_lock);
2444 if (current->signal->leader && (task_session(current) == tty->session))
2448 * The process must be a session leader and
2449 * not have a controlling tty already.
2451 if (!current->signal->leader || current->signal->tty) {
2458 * This tty is already the controlling
2459 * tty for another session group!
2461 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2465 session_clear_tty(tty->session);
2473 read_unlock(&tasklist_lock);
2479 * tty_get_pgrp - return a ref counted pgrp pid
2482 * Returns a refcounted instance of the pid struct for the process
2483 * group controlling the tty.
2486 struct pid *tty_get_pgrp(struct tty_struct *tty)
2488 unsigned long flags;
2491 spin_lock_irqsave(&tty->ctrl_lock, flags);
2492 pgrp = get_pid(tty->pgrp);
2493 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2497 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2500 * This checks not only the pgrp, but falls back on the pid if no
2501 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
2504 * The caller must hold rcu lock or the tasklist lock.
2506 static struct pid *session_of_pgrp(struct pid *pgrp)
2508 struct task_struct *p;
2509 struct pid *sid = NULL;
2511 p = pid_task(pgrp, PIDTYPE_PGID);
2513 p = pid_task(pgrp, PIDTYPE_PID);
2515 sid = task_session(p);
2521 * tiocgpgrp - get process group
2522 * @tty: tty passed by user
2523 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2526 * Obtain the process group of the tty. If there is no process group
2529 * Locking: none. Reference to current->signal->tty is safe.
2532 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2537 * (tty == real_tty) is a cheap way of
2538 * testing if the tty is NOT a master pty.
2540 if (tty == real_tty && current->signal->tty != real_tty)
2542 pid = tty_get_pgrp(real_tty);
2543 ret = put_user(pid_vnr(pid), p);
2549 * tiocspgrp - attempt to set process group
2550 * @tty: tty passed by user
2551 * @real_tty: tty side device matching tty passed by user
2554 * Set the process group of the tty to the session passed. Only
2555 * permitted where the tty session is our session.
2557 * Locking: RCU, ctrl lock
2560 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2564 int retval = tty_check_change(real_tty);
2565 unsigned long flags;
2571 if (!current->signal->tty ||
2572 (current->signal->tty != real_tty) ||
2573 (real_tty->session != task_session(current)))
2575 if (get_user(pgrp_nr, p))
2580 pgrp = find_vpid(pgrp_nr);
2585 if (session_of_pgrp(pgrp) != task_session(current))
2588 spin_lock_irqsave(&tty->ctrl_lock, flags);
2589 put_pid(real_tty->pgrp);
2590 real_tty->pgrp = get_pid(pgrp);
2591 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2598 * tiocgsid - get session id
2599 * @tty: tty passed by user
2600 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2601 * @p: pointer to returned session id
2603 * Obtain the session id of the tty. If there is no session
2606 * Locking: none. Reference to current->signal->tty is safe.
2609 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2612 * (tty == real_tty) is a cheap way of
2613 * testing if the tty is NOT a master pty.
2615 if (tty == real_tty && current->signal->tty != real_tty)
2617 if (!real_tty->session)
2619 return put_user(pid_vnr(real_tty->session), p);
2623 * tiocsetd - set line discipline
2625 * @p: pointer to user data
2627 * Set the line discipline according to user request.
2629 * Locking: see tty_set_ldisc, this function is just a helper
2632 static int tiocsetd(struct tty_struct *tty, int __user *p)
2637 if (get_user(ldisc, p))
2640 ret = tty_set_ldisc(tty, ldisc);
2646 * send_break - performed time break
2647 * @tty: device to break on
2648 * @duration: timeout in mS
2650 * Perform a timed break on hardware that lacks its own driver level
2651 * timed break functionality.
2654 * atomic_write_lock serializes
2658 static int send_break(struct tty_struct *tty, unsigned int duration)
2662 if (tty->ops->break_ctl == NULL)
2665 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2666 retval = tty->ops->break_ctl(tty, duration);
2668 /* Do the work ourselves */
2669 if (tty_write_lock(tty, 0) < 0)
2671 retval = tty->ops->break_ctl(tty, -1);
2674 if (!signal_pending(current))
2675 msleep_interruptible(duration);
2676 retval = tty->ops->break_ctl(tty, 0);
2678 tty_write_unlock(tty);
2679 if (signal_pending(current))
2686 * tty_tiocmget - get modem status
2688 * @file: user file pointer
2689 * @p: pointer to result
2691 * Obtain the modem status bits from the tty driver if the feature
2692 * is supported. Return -EINVAL if it is not available.
2694 * Locking: none (up to the driver)
2697 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2699 int retval = -EINVAL;
2701 if (tty->ops->tiocmget) {
2702 retval = tty->ops->tiocmget(tty);
2705 retval = put_user(retval, p);
2711 * tty_tiocmset - set modem status
2713 * @cmd: command - clear bits, set bits or set all
2714 * @p: pointer to desired bits
2716 * Set the modem status bits from the tty driver if the feature
2717 * is supported. Return -EINVAL if it is not available.
2719 * Locking: none (up to the driver)
2722 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2726 unsigned int set, clear, val;
2728 if (tty->ops->tiocmset == NULL)
2731 retval = get_user(val, p);
2747 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2748 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2749 return tty->ops->tiocmset(tty, set, clear);
2752 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2754 int retval = -EINVAL;
2755 struct serial_icounter_struct icount;
2756 memset(&icount, 0, sizeof(icount));
2757 if (tty->ops->get_icount)
2758 retval = tty->ops->get_icount(tty, &icount);
2761 if (copy_to_user(arg, &icount, sizeof(icount)))
2766 static void tty_warn_deprecated_flags(struct serial_struct __user *ss)
2768 static DEFINE_RATELIMIT_STATE(depr_flags,
2769 DEFAULT_RATELIMIT_INTERVAL,
2770 DEFAULT_RATELIMIT_BURST);
2771 char comm[TASK_COMM_LEN];
2774 if (get_user(flags, &ss->flags))
2777 flags &= ASYNC_DEPRECATED;
2779 if (flags && __ratelimit(&depr_flags))
2780 pr_warning("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2781 __func__, get_task_comm(comm, current), flags);
2785 * if pty, return the slave side (real_tty)
2786 * otherwise, return self
2788 static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2790 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2791 tty->driver->subtype == PTY_TYPE_MASTER)
2797 * Split this up, as gcc can choke on it otherwise..
2799 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2801 struct tty_struct *tty = file_tty(file);
2802 struct tty_struct *real_tty;
2803 void __user *p = (void __user *)arg;
2805 struct tty_ldisc *ld;
2807 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2810 real_tty = tty_pair_get_tty(tty);
2813 * Factor out some common prep work
2821 retval = tty_check_change(tty);
2824 if (cmd != TIOCCBRK) {
2825 tty_wait_until_sent(tty, 0);
2826 if (signal_pending(current))
2837 return tiocsti(tty, p);
2839 return tiocgwinsz(real_tty, p);
2841 return tiocswinsz(real_tty, p);
2843 return real_tty != tty ? -EINVAL : tioccons(file);
2845 return fionbio(file, p);
2847 set_bit(TTY_EXCLUSIVE, &tty->flags);
2850 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2854 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2855 return put_user(excl, (int __user *)p);
2858 if (current->signal->tty != tty)
2863 return tiocsctty(tty, arg);
2865 return tiocgpgrp(tty, real_tty, p);
2867 return tiocspgrp(tty, real_tty, p);
2869 return tiocgsid(tty, real_tty, p);
2871 return put_user(tty->ldisc->ops->num, (int __user *)p);
2873 return tiocsetd(tty, p);
2875 if (!capable(CAP_SYS_ADMIN))
2881 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2882 return put_user(ret, (unsigned int __user *)p);
2887 case TIOCSBRK: /* Turn break on, unconditionally */
2888 if (tty->ops->break_ctl)
2889 return tty->ops->break_ctl(tty, -1);
2891 case TIOCCBRK: /* Turn break off, unconditionally */
2892 if (tty->ops->break_ctl)
2893 return tty->ops->break_ctl(tty, 0);
2895 case TCSBRK: /* SVID version: non-zero arg --> no break */
2896 /* non-zero arg means wait for all output data
2897 * to be sent (performed above) but don't send break.
2898 * This is used by the tcdrain() termios function.
2901 return send_break(tty, 250);
2903 case TCSBRKP: /* support for POSIX tcsendbreak() */
2904 return send_break(tty, arg ? arg*100 : 250);
2907 return tty_tiocmget(tty, p);
2911 return tty_tiocmset(tty, cmd, p);
2913 retval = tty_tiocgicount(tty, p);
2914 /* For the moment allow fall through to the old method */
2915 if (retval != -EINVAL)
2922 /* flush tty buffer and allow ldisc to process ioctl */
2923 tty_buffer_flush(tty, NULL);
2928 tty_warn_deprecated_flags(p);
2931 if (tty->ops->ioctl) {
2932 retval = tty->ops->ioctl(tty, cmd, arg);
2933 if (retval != -ENOIOCTLCMD)
2936 ld = tty_ldisc_ref_wait(tty);
2938 if (ld->ops->ioctl) {
2939 retval = ld->ops->ioctl(tty, file, cmd, arg);
2940 if (retval == -ENOIOCTLCMD)
2943 tty_ldisc_deref(ld);
2947 #ifdef CONFIG_COMPAT
2948 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2951 struct tty_struct *tty = file_tty(file);
2952 struct tty_ldisc *ld;
2953 int retval = -ENOIOCTLCMD;
2955 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2958 if (tty->ops->compat_ioctl) {
2959 retval = tty->ops->compat_ioctl(tty, cmd, arg);
2960 if (retval != -ENOIOCTLCMD)
2964 ld = tty_ldisc_ref_wait(tty);
2965 if (ld->ops->compat_ioctl)
2966 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2968 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
2969 tty_ldisc_deref(ld);
2975 static int this_tty(const void *t, struct file *file, unsigned fd)
2977 if (likely(file->f_op->read != tty_read))
2979 return file_tty(file) != t ? 0 : fd + 1;
2983 * This implements the "Secure Attention Key" --- the idea is to
2984 * prevent trojan horses by killing all processes associated with this
2985 * tty when the user hits the "Secure Attention Key". Required for
2986 * super-paranoid applications --- see the Orange Book for more details.
2988 * This code could be nicer; ideally it should send a HUP, wait a few
2989 * seconds, then send a INT, and then a KILL signal. But you then
2990 * have to coordinate with the init process, since all processes associated
2991 * with the current tty must be dead before the new getty is allowed
2994 * Now, if it would be correct ;-/ The current code has a nasty hole -
2995 * it doesn't catch files in flight. We may send the descriptor to ourselves
2996 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2998 * Nasty bug: do_SAK is being called in interrupt context. This can
2999 * deadlock. We punt it up to process context. AKPM - 16Mar2001
3001 void __do_SAK(struct tty_struct *tty)
3006 struct task_struct *g, *p;
3007 struct pid *session;
3012 session = tty->session;
3014 tty_ldisc_flush(tty);
3016 tty_driver_flush_buffer(tty);
3018 read_lock(&tasklist_lock);
3019 /* Kill the entire session */
3020 do_each_pid_task(session, PIDTYPE_SID, p) {
3021 printk(KERN_NOTICE "SAK: killed process %d"
3022 " (%s): task_session(p)==tty->session\n",
3023 task_pid_nr(p), p->comm);
3024 send_sig(SIGKILL, p, 1);
3025 } while_each_pid_task(session, PIDTYPE_SID, p);
3026 /* Now kill any processes that happen to have the
3029 do_each_thread(g, p) {
3030 if (p->signal->tty == tty) {
3031 printk(KERN_NOTICE "SAK: killed process %d"
3032 " (%s): task_session(p)==tty->session\n",
3033 task_pid_nr(p), p->comm);
3034 send_sig(SIGKILL, p, 1);
3038 i = iterate_fd(p->files, 0, this_tty, tty);
3040 printk(KERN_NOTICE "SAK: killed process %d"
3041 " (%s): fd#%d opened to the tty\n",
3042 task_pid_nr(p), p->comm, i - 1);
3043 force_sig(SIGKILL, p);
3046 } while_each_thread(g, p);
3047 read_unlock(&tasklist_lock);
3051 static void do_SAK_work(struct work_struct *work)
3053 struct tty_struct *tty =
3054 container_of(work, struct tty_struct, SAK_work);
3059 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3060 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3061 * the values which we write to it will be identical to the values which it
3062 * already has. --akpm
3064 void do_SAK(struct tty_struct *tty)
3068 schedule_work(&tty->SAK_work);
3071 EXPORT_SYMBOL(do_SAK);
3073 static int dev_match_devt(struct device *dev, const void *data)
3075 const dev_t *devt = data;
3076 return dev->devt == *devt;
3079 /* Must put_device() after it's unused! */
3080 static struct device *tty_get_device(struct tty_struct *tty)
3082 dev_t devt = tty_devnum(tty);
3083 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
3090 * This subroutine allocates and initializes a tty structure.
3092 * Locking: none - tty in question is not exposed at this point
3095 struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
3097 struct tty_struct *tty;
3099 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
3103 kref_init(&tty->kref);
3104 tty->magic = TTY_MAGIC;
3105 tty_ldisc_init(tty);
3106 tty->session = NULL;
3108 mutex_init(&tty->legacy_mutex);
3109 mutex_init(&tty->throttle_mutex);
3110 init_rwsem(&tty->termios_rwsem);
3111 mutex_init(&tty->winsize_mutex);
3112 init_ldsem(&tty->ldisc_sem);
3113 init_waitqueue_head(&tty->write_wait);
3114 init_waitqueue_head(&tty->read_wait);
3115 INIT_WORK(&tty->hangup_work, do_tty_hangup);
3116 mutex_init(&tty->atomic_write_lock);
3117 spin_lock_init(&tty->ctrl_lock);
3118 spin_lock_init(&tty->flow_lock);
3119 INIT_LIST_HEAD(&tty->tty_files);
3120 INIT_WORK(&tty->SAK_work, do_SAK_work);
3122 tty->driver = driver;
3123 tty->ops = driver->ops;
3125 tty_line_name(driver, idx, tty->name);
3126 tty->dev = tty_get_device(tty);
3132 * deinitialize_tty_struct
3133 * @tty: tty to deinitialize
3135 * This subroutine deinitializes a tty structure that has been newly
3136 * allocated but tty_release cannot be called on that yet.
3138 * Locking: none - tty in question must not be exposed at this point
3140 void deinitialize_tty_struct(struct tty_struct *tty)
3142 tty_ldisc_deinit(tty);
3146 * tty_put_char - write one character to a tty
3150 * Write one byte to the tty using the provided put_char method
3151 * if present. Returns the number of characters successfully output.
3153 * Note: the specific put_char operation in the driver layer may go
3154 * away soon. Don't call it directly, use this method
3157 int tty_put_char(struct tty_struct *tty, unsigned char ch)
3159 if (tty->ops->put_char)
3160 return tty->ops->put_char(tty, ch);
3161 return tty->ops->write(tty, &ch, 1);
3163 EXPORT_SYMBOL_GPL(tty_put_char);
3165 struct class *tty_class;
3167 static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3168 unsigned int index, unsigned int count)
3170 /* init here, since reused cdevs cause crashes */
3171 cdev_init(&driver->cdevs[index], &tty_fops);
3172 driver->cdevs[index].owner = driver->owner;
3173 return cdev_add(&driver->cdevs[index], dev, count);
3177 * tty_register_device - register a tty device
3178 * @driver: the tty driver that describes the tty device
3179 * @index: the index in the tty driver for this tty device
3180 * @device: a struct device that is associated with this tty device.
3181 * This field is optional, if there is no known struct device
3182 * for this tty device it can be set to NULL safely.
3184 * Returns a pointer to the struct device for this tty device
3185 * (or ERR_PTR(-EFOO) on error).
3187 * This call is required to be made to register an individual tty device
3188 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3189 * that bit is not set, this function should not be called by a tty
3195 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3196 struct device *device)
3198 return tty_register_device_attr(driver, index, device, NULL, NULL);
3200 EXPORT_SYMBOL(tty_register_device);
3202 static void tty_device_create_release(struct device *dev)
3204 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3209 * tty_register_device_attr - register a tty device
3210 * @driver: the tty driver that describes the tty device
3211 * @index: the index in the tty driver for this tty device
3212 * @device: a struct device that is associated with this tty device.
3213 * This field is optional, if there is no known struct device
3214 * for this tty device it can be set to NULL safely.
3215 * @drvdata: Driver data to be set to device.
3216 * @attr_grp: Attribute group to be set on device.
3218 * Returns a pointer to the struct device for this tty device
3219 * (or ERR_PTR(-EFOO) on error).
3221 * This call is required to be made to register an individual tty device
3222 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3223 * that bit is not set, this function should not be called by a tty
3228 struct device *tty_register_device_attr(struct tty_driver *driver,
3229 unsigned index, struct device *device,
3231 const struct attribute_group **attr_grp)
3234 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3235 struct device *dev = NULL;
3236 int retval = -ENODEV;
3239 if (index >= driver->num) {
3240 printk(KERN_ERR "Attempt to register invalid tty line number "
3242 return ERR_PTR(-EINVAL);
3245 if (driver->type == TTY_DRIVER_TYPE_PTY)
3246 pty_line_name(driver, index, name);
3248 tty_line_name(driver, index, name);
3250 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3251 retval = tty_cdev_add(driver, devt, index, 1);
3257 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3264 dev->class = tty_class;
3265 dev->parent = device;
3266 dev->release = tty_device_create_release;
3267 dev_set_name(dev, "%s", name);
3268 dev->groups = attr_grp;
3269 dev_set_drvdata(dev, drvdata);
3271 retval = device_register(dev);
3280 cdev_del(&driver->cdevs[index]);
3281 return ERR_PTR(retval);
3283 EXPORT_SYMBOL_GPL(tty_register_device_attr);
3286 * tty_unregister_device - unregister a tty device
3287 * @driver: the tty driver that describes the tty device
3288 * @index: the index in the tty driver for this tty device
3290 * If a tty device is registered with a call to tty_register_device() then
3291 * this function must be called when the tty device is gone.
3296 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3298 device_destroy(tty_class,
3299 MKDEV(driver->major, driver->minor_start) + index);
3300 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC))
3301 cdev_del(&driver->cdevs[index]);
3303 EXPORT_SYMBOL(tty_unregister_device);
3306 * __tty_alloc_driver -- allocate tty driver
3307 * @lines: count of lines this driver can handle at most
3308 * @owner: module which is repsonsible for this driver
3309 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3311 * This should not be called directly, some of the provided macros should be
3312 * used instead. Use IS_ERR and friends on @retval.
3314 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3315 unsigned long flags)
3317 struct tty_driver *driver;
3318 unsigned int cdevs = 1;
3321 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3322 return ERR_PTR(-EINVAL);
3324 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3326 return ERR_PTR(-ENOMEM);
3328 kref_init(&driver->kref);
3329 driver->magic = TTY_DRIVER_MAGIC;
3330 driver->num = lines;
3331 driver->owner = owner;
3332 driver->flags = flags;
3334 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3335 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3337 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3339 if (!driver->ttys || !driver->termios) {
3345 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3346 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3348 if (!driver->ports) {
3355 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3356 if (!driver->cdevs) {
3363 kfree(driver->ports);
3364 kfree(driver->ttys);
3365 kfree(driver->termios);
3367 return ERR_PTR(err);
3369 EXPORT_SYMBOL(__tty_alloc_driver);
3371 static void destruct_tty_driver(struct kref *kref)
3373 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3375 struct ktermios *tp;
3377 if (driver->flags & TTY_DRIVER_INSTALLED) {
3379 * Free the termios and termios_locked structures because
3380 * we don't want to get memory leaks when modular tty
3381 * drivers are removed from the kernel.
3383 for (i = 0; i < driver->num; i++) {
3384 tp = driver->termios[i];
3386 driver->termios[i] = NULL;
3389 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3390 tty_unregister_device(driver, i);
3392 proc_tty_unregister_driver(driver);
3393 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3394 cdev_del(&driver->cdevs[0]);
3396 kfree(driver->cdevs);
3397 kfree(driver->ports);
3398 kfree(driver->termios);
3399 kfree(driver->ttys);
3403 void tty_driver_kref_put(struct tty_driver *driver)
3405 kref_put(&driver->kref, destruct_tty_driver);
3407 EXPORT_SYMBOL(tty_driver_kref_put);
3409 void tty_set_operations(struct tty_driver *driver,
3410 const struct tty_operations *op)
3414 EXPORT_SYMBOL(tty_set_operations);
3416 void put_tty_driver(struct tty_driver *d)
3418 tty_driver_kref_put(d);
3420 EXPORT_SYMBOL(put_tty_driver);
3423 * Called by a tty driver to register itself.
3425 int tty_register_driver(struct tty_driver *driver)
3432 if (!driver->major) {
3433 error = alloc_chrdev_region(&dev, driver->minor_start,
3434 driver->num, driver->name);
3436 driver->major = MAJOR(dev);
3437 driver->minor_start = MINOR(dev);
3440 dev = MKDEV(driver->major, driver->minor_start);
3441 error = register_chrdev_region(dev, driver->num, driver->name);
3446 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3447 error = tty_cdev_add(driver, dev, 0, driver->num);
3449 goto err_unreg_char;
3452 mutex_lock(&tty_mutex);
3453 list_add(&driver->tty_drivers, &tty_drivers);
3454 mutex_unlock(&tty_mutex);
3456 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3457 for (i = 0; i < driver->num; i++) {
3458 d = tty_register_device(driver, i, NULL);
3461 goto err_unreg_devs;
3465 proc_tty_register_driver(driver);
3466 driver->flags |= TTY_DRIVER_INSTALLED;
3470 for (i--; i >= 0; i--)
3471 tty_unregister_device(driver, i);
3473 mutex_lock(&tty_mutex);
3474 list_del(&driver->tty_drivers);
3475 mutex_unlock(&tty_mutex);
3478 unregister_chrdev_region(dev, driver->num);
3482 EXPORT_SYMBOL(tty_register_driver);
3485 * Called by a tty driver to unregister itself.
3487 int tty_unregister_driver(struct tty_driver *driver)
3491 if (driver->refcount)
3494 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3496 mutex_lock(&tty_mutex);
3497 list_del(&driver->tty_drivers);
3498 mutex_unlock(&tty_mutex);
3502 EXPORT_SYMBOL(tty_unregister_driver);
3504 dev_t tty_devnum(struct tty_struct *tty)
3506 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3508 EXPORT_SYMBOL(tty_devnum);
3510 void tty_default_fops(struct file_operations *fops)
3516 * Initialize the console device. This is called *early*, so
3517 * we can't necessarily depend on lots of kernel help here.
3518 * Just do some early initializations, and do the complex setup
3521 void __init console_init(void)
3525 /* Setup the default TTY line discipline. */
3529 * set up the console device so that later boot sequences can
3530 * inform about problems etc..
3532 call = __con_initcall_start;
3533 while (call < __con_initcall_end) {
3539 static char *tty_devnode(struct device *dev, umode_t *mode)
3543 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3544 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3549 static int __init tty_class_init(void)
3551 tty_class = class_create(THIS_MODULE, "tty");
3552 if (IS_ERR(tty_class))
3553 return PTR_ERR(tty_class);
3554 tty_class->devnode = tty_devnode;
3558 postcore_initcall(tty_class_init);
3560 /* 3/2004 jmc: why do these devices exist? */
3561 static struct cdev tty_cdev, console_cdev;
3563 static ssize_t show_cons_active(struct device *dev,
3564 struct device_attribute *attr, char *buf)
3566 struct console *cs[16];
3572 for_each_console(c) {
3577 if ((c->flags & CON_ENABLED) == 0)
3580 if (i >= ARRAY_SIZE(cs))
3584 int index = cs[i]->index;
3585 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3587 /* don't resolve tty0 as some programs depend on it */
3588 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3589 count += tty_line_name(drv, index, buf + count);
3591 count += sprintf(buf + count, "%s%d",
3592 cs[i]->name, cs[i]->index);
3594 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3600 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3602 static struct attribute *cons_dev_attrs[] = {
3603 &dev_attr_active.attr,
3607 ATTRIBUTE_GROUPS(cons_dev);
3609 static struct device *consdev;
3611 void console_sysfs_notify(void)
3614 sysfs_notify(&consdev->kobj, NULL, "active");
3618 * Ok, now we can initialize the rest of the tty devices and can count
3619 * on memory allocations, interrupts etc..
3621 int __init tty_init(void)
3623 cdev_init(&tty_cdev, &tty_fops);
3624 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3625 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3626 panic("Couldn't register /dev/tty driver\n");
3627 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3629 cdev_init(&console_cdev, &console_fops);
3630 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3631 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3632 panic("Couldn't register /dev/console driver\n");
3633 consdev = device_create_with_groups(tty_class, NULL,
3634 MKDEV(TTYAUX_MAJOR, 1), NULL,
3635 cons_dev_groups, "console");
3636 if (IS_ERR(consdev))
3640 vty_init(&console_fops);