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)
171 put_device(tty->dev);
172 kfree(tty->write_buf);
173 tty->magic = 0xDEADDEAD;
177 static inline struct tty_struct *file_tty(struct file *file)
179 return ((struct tty_file_private *)file->private_data)->tty;
182 int tty_alloc_file(struct file *file)
184 struct tty_file_private *priv;
186 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
190 file->private_data = priv;
195 /* Associate a new file with the tty structure */
196 void tty_add_file(struct tty_struct *tty, struct file *file)
198 struct tty_file_private *priv = file->private_data;
203 spin_lock(&tty_files_lock);
204 list_add(&priv->list, &tty->tty_files);
205 spin_unlock(&tty_files_lock);
209 * tty_free_file - free file->private_data
211 * This shall be used only for fail path handling when tty_add_file was not
214 void tty_free_file(struct file *file)
216 struct tty_file_private *priv = file->private_data;
218 file->private_data = NULL;
222 /* Delete file from its tty */
223 static void tty_del_file(struct file *file)
225 struct tty_file_private *priv = file->private_data;
227 spin_lock(&tty_files_lock);
228 list_del(&priv->list);
229 spin_unlock(&tty_files_lock);
234 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
237 * tty_name - return tty naming
238 * @tty: tty structure
239 * @buf: buffer for output
241 * Convert a tty structure into a name. The name reflects the kernel
242 * naming policy and if udev is in use may not reflect user space
247 char *tty_name(struct tty_struct *tty, char *buf)
249 if (!tty) /* Hmm. NULL pointer. That's fun. */
250 strcpy(buf, "NULL tty");
252 strcpy(buf, tty->name);
256 EXPORT_SYMBOL(tty_name);
258 int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
261 #ifdef TTY_PARANOIA_CHECK
264 "null TTY for (%d:%d) in %s\n",
265 imajor(inode), iminor(inode), routine);
268 if (tty->magic != TTY_MAGIC) {
270 "bad magic number for tty struct (%d:%d) in %s\n",
271 imajor(inode), iminor(inode), routine);
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)
983 (tty->ops->stop)(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 /* We limit tty time update visibility to every 8 seconds or so. */
1029 static void tty_update_time(struct timespec *time)
1031 unsigned long sec = get_seconds() & ~7;
1032 if ((long)(sec - time->tv_sec) > 0)
1037 * tty_read - read method for tty device files
1038 * @file: pointer to tty file
1040 * @count: size of user buffer
1043 * Perform the read system call function on this terminal device. Checks
1044 * for hung up devices before calling the line discipline method.
1047 * Locks the line discipline internally while needed. Multiple
1048 * read calls may be outstanding in parallel.
1051 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
1055 struct inode *inode = file_inode(file);
1056 struct tty_struct *tty = file_tty(file);
1057 struct tty_ldisc *ld;
1059 if (tty_paranoia_check(tty, inode, "tty_read"))
1061 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
1064 /* We want to wait for the line discipline to sort out in this
1066 ld = tty_ldisc_ref_wait(tty);
1068 i = (ld->ops->read)(tty, file, buf, count);
1071 tty_ldisc_deref(ld);
1074 tty_update_time(&inode->i_atime);
1079 static void tty_write_unlock(struct tty_struct *tty)
1081 mutex_unlock(&tty->atomic_write_lock);
1082 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
1085 static int tty_write_lock(struct tty_struct *tty, int ndelay)
1087 if (!mutex_trylock(&tty->atomic_write_lock)) {
1090 if (mutex_lock_interruptible(&tty->atomic_write_lock))
1091 return -ERESTARTSYS;
1097 * Split writes up in sane blocksizes to avoid
1098 * denial-of-service type attacks
1100 static inline ssize_t do_tty_write(
1101 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
1102 struct tty_struct *tty,
1104 const char __user *buf,
1107 ssize_t ret, written = 0;
1110 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
1115 * We chunk up writes into a temporary buffer. This
1116 * simplifies low-level drivers immensely, since they
1117 * don't have locking issues and user mode accesses.
1119 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1122 * The default chunk-size is 2kB, because the NTTY
1123 * layer has problems with bigger chunks. It will
1124 * claim to be able to handle more characters than
1127 * FIXME: This can probably go away now except that 64K chunks
1128 * are too likely to fail unless switched to vmalloc...
1131 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1136 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1137 if (tty->write_cnt < chunk) {
1138 unsigned char *buf_chunk;
1143 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1148 kfree(tty->write_buf);
1149 tty->write_cnt = chunk;
1150 tty->write_buf = buf_chunk;
1153 /* Do the write .. */
1155 size_t size = count;
1159 if (copy_from_user(tty->write_buf, buf, size))
1161 ret = write(tty, file, tty->write_buf, size);
1170 if (signal_pending(current))
1175 tty_update_time(&file_inode(file)->i_mtime);
1179 tty_write_unlock(tty);
1184 * tty_write_message - write a message to a certain tty, not just the console.
1185 * @tty: the destination tty_struct
1186 * @msg: the message to write
1188 * This is used for messages that need to be redirected to a specific tty.
1189 * We don't put it into the syslog queue right now maybe in the future if
1192 * We must still hold the BTM and test the CLOSING flag for the moment.
1195 void tty_write_message(struct tty_struct *tty, char *msg)
1198 mutex_lock(&tty->atomic_write_lock);
1200 if (tty->ops->write && tty->count > 0) {
1202 tty->ops->write(tty, msg, strlen(msg));
1205 tty_write_unlock(tty);
1212 * tty_write - write method for tty device file
1213 * @file: tty file pointer
1214 * @buf: user data to write
1215 * @count: bytes to write
1218 * Write data to a tty device via the line discipline.
1221 * Locks the line discipline as required
1222 * Writes to the tty driver are serialized by the atomic_write_lock
1223 * and are then processed in chunks to the device. The line discipline
1224 * write method will not be invoked in parallel for each device.
1227 static ssize_t tty_write(struct file *file, const char __user *buf,
1228 size_t count, loff_t *ppos)
1230 struct tty_struct *tty = file_tty(file);
1231 struct tty_ldisc *ld;
1234 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1236 if (!tty || !tty->ops->write ||
1237 (test_bit(TTY_IO_ERROR, &tty->flags)))
1239 /* Short term debug to catch buggy drivers */
1240 if (tty->ops->write_room == NULL)
1241 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1243 ld = tty_ldisc_ref_wait(tty);
1244 if (!ld->ops->write)
1247 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1248 tty_ldisc_deref(ld);
1252 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1253 size_t count, loff_t *ppos)
1255 struct file *p = NULL;
1257 spin_lock(&redirect_lock);
1259 p = get_file(redirect);
1260 spin_unlock(&redirect_lock);
1264 res = vfs_write(p, buf, count, &p->f_pos);
1268 return tty_write(file, buf, count, ppos);
1272 * tty_send_xchar - send priority character
1274 * Send a high priority character to the tty even if stopped
1276 * Locking: none for xchar method, write ordering for write method.
1279 int tty_send_xchar(struct tty_struct *tty, char ch)
1281 int was_stopped = tty->stopped;
1283 if (tty->ops->send_xchar) {
1284 tty->ops->send_xchar(tty, ch);
1288 if (tty_write_lock(tty, 0) < 0)
1289 return -ERESTARTSYS;
1293 tty->ops->write(tty, &ch, 1);
1296 tty_write_unlock(tty);
1300 static char ptychar[] = "pqrstuvwxyzabcde";
1303 * pty_line_name - generate name for a pty
1304 * @driver: the tty driver in use
1305 * @index: the minor number
1306 * @p: output buffer of at least 6 bytes
1308 * Generate a name from a driver reference and write it to the output
1313 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1315 int i = index + driver->name_base;
1316 /* ->name is initialized to "ttyp", but "tty" is expected */
1317 sprintf(p, "%s%c%x",
1318 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1319 ptychar[i >> 4 & 0xf], i & 0xf);
1323 * tty_line_name - generate name for a tty
1324 * @driver: the tty driver in use
1325 * @index: the minor number
1326 * @p: output buffer of at least 7 bytes
1328 * Generate a name from a driver reference and write it to the output
1333 static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1335 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1336 return sprintf(p, "%s", driver->name);
1338 return sprintf(p, "%s%d", driver->name,
1339 index + driver->name_base);
1343 * tty_driver_lookup_tty() - find an existing tty, if any
1344 * @driver: the driver for the tty
1345 * @idx: the minor number
1347 * Return the tty, if found. If not found, return NULL or ERR_PTR() if the
1348 * driver lookup() method returns an error.
1350 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1352 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1353 struct inode *inode, int idx)
1355 struct tty_struct *tty;
1357 if (driver->ops->lookup)
1358 tty = driver->ops->lookup(driver, inode, idx);
1360 tty = driver->ttys[idx];
1368 * tty_init_termios - helper for termios setup
1369 * @tty: the tty to set up
1371 * Initialise the termios structures for this tty. Thus runs under
1372 * the tty_mutex currently so we can be relaxed about ordering.
1375 int tty_init_termios(struct tty_struct *tty)
1377 struct ktermios *tp;
1378 int idx = tty->index;
1380 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1381 tty->termios = tty->driver->init_termios;
1383 /* Check for lazy saved data */
1384 tp = tty->driver->termios[idx];
1388 tty->termios = tty->driver->init_termios;
1390 /* Compatibility until drivers always set this */
1391 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1392 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1395 EXPORT_SYMBOL_GPL(tty_init_termios);
1397 int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1399 int ret = tty_init_termios(tty);
1403 tty_driver_kref_get(driver);
1405 driver->ttys[tty->index] = tty;
1408 EXPORT_SYMBOL_GPL(tty_standard_install);
1411 * tty_driver_install_tty() - install a tty entry in the driver
1412 * @driver: the driver for the tty
1415 * Install a tty object into the driver tables. The tty->index field
1416 * will be set by the time this is called. This method is responsible
1417 * for ensuring any need additional structures are allocated and
1420 * Locking: tty_mutex for now
1422 static int tty_driver_install_tty(struct tty_driver *driver,
1423 struct tty_struct *tty)
1425 return driver->ops->install ? driver->ops->install(driver, tty) :
1426 tty_standard_install(driver, tty);
1430 * tty_driver_remove_tty() - remove a tty from the driver tables
1431 * @driver: the driver for the tty
1432 * @idx: the minor number
1434 * Remvoe a tty object from the driver tables. The tty->index field
1435 * will be set by the time this is called.
1437 * Locking: tty_mutex for now
1439 void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1441 if (driver->ops->remove)
1442 driver->ops->remove(driver, tty);
1444 driver->ttys[tty->index] = NULL;
1448 * tty_reopen() - fast re-open of an open tty
1449 * @tty - the tty to open
1451 * Return 0 on success, -errno on error.
1452 * Re-opens on master ptys are not allowed and return -EIO.
1454 * Locking: Caller must hold tty_lock
1456 static int tty_reopen(struct tty_struct *tty)
1458 struct tty_driver *driver = tty->driver;
1463 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1464 driver->subtype == PTY_TYPE_MASTER)
1469 WARN_ON(!tty->ldisc);
1475 * tty_init_dev - initialise a tty device
1476 * @driver: tty driver we are opening a device on
1477 * @idx: device index
1478 * @ret_tty: returned tty structure
1480 * Prepare a tty device. This may not be a "new" clean device but
1481 * could also be an active device. The pty drivers require special
1482 * handling because of this.
1485 * The function is called under the tty_mutex, which
1486 * protects us from the tty struct or driver itself going away.
1488 * On exit the tty device has the line discipline attached and
1489 * a reference count of 1. If a pair was created for pty/tty use
1490 * and the other was a pty master then it too has a reference count of 1.
1492 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1493 * failed open. The new code protects the open with a mutex, so it's
1494 * really quite straightforward. The mutex locking can probably be
1495 * relaxed for the (most common) case of reopening a tty.
1498 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1500 struct tty_struct *tty;
1504 * First time open is complex, especially for PTY devices.
1505 * This code guarantees that either everything succeeds and the
1506 * TTY is ready for operation, or else the table slots are vacated
1507 * and the allocated memory released. (Except that the termios
1508 * and locked termios may be retained.)
1511 if (!try_module_get(driver->owner))
1512 return ERR_PTR(-ENODEV);
1514 tty = alloc_tty_struct(driver, idx);
1517 goto err_module_put;
1521 retval = tty_driver_install_tty(driver, tty);
1523 goto err_deinit_tty;
1526 tty->port = driver->ports[idx];
1528 WARN_RATELIMIT(!tty->port,
1529 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1530 __func__, tty->driver->name);
1532 tty->port->itty = tty;
1535 * Structures all installed ... call the ldisc open routines.
1536 * If we fail here just call release_tty to clean up. No need
1537 * to decrement the use counts, as release_tty doesn't care.
1539 retval = tty_ldisc_setup(tty, tty->link);
1541 goto err_release_tty;
1542 /* Return the tty locked so that it cannot vanish under the caller */
1547 deinitialize_tty_struct(tty);
1548 free_tty_struct(tty);
1550 module_put(driver->owner);
1551 return ERR_PTR(retval);
1553 /* call the tty release_tty routine to clean out this slot */
1556 printk_ratelimited(KERN_INFO "tty_init_dev: ldisc open failed, "
1557 "clearing slot %d\n", idx);
1558 release_tty(tty, idx);
1559 return ERR_PTR(retval);
1562 void tty_free_termios(struct tty_struct *tty)
1564 struct ktermios *tp;
1565 int idx = tty->index;
1567 /* If the port is going to reset then it has no termios to save */
1568 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1571 /* Stash the termios data */
1572 tp = tty->driver->termios[idx];
1574 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1576 pr_warn("tty: no memory to save termios state.\n");
1579 tty->driver->termios[idx] = tp;
1583 EXPORT_SYMBOL(tty_free_termios);
1586 * tty_flush_works - flush all works of a tty
1587 * @tty: tty device to flush works for
1589 * Sync flush all works belonging to @tty.
1591 static void tty_flush_works(struct tty_struct *tty)
1593 flush_work(&tty->SAK_work);
1594 flush_work(&tty->hangup_work);
1598 * release_one_tty - release tty structure memory
1599 * @kref: kref of tty we are obliterating
1601 * Releases memory associated with a tty structure, and clears out the
1602 * driver table slots. This function is called when a device is no longer
1603 * in use. It also gets called when setup of a device fails.
1606 * takes the file list lock internally when working on the list
1607 * of ttys that the driver keeps.
1609 * This method gets called from a work queue so that the driver private
1610 * cleanup ops can sleep (needed for USB at least)
1612 static void release_one_tty(struct work_struct *work)
1614 struct tty_struct *tty =
1615 container_of(work, struct tty_struct, hangup_work);
1616 struct tty_driver *driver = tty->driver;
1617 struct module *owner = driver->owner;
1619 if (tty->ops->cleanup)
1620 tty->ops->cleanup(tty);
1623 tty_driver_kref_put(driver);
1626 spin_lock(&tty_files_lock);
1627 list_del_init(&tty->tty_files);
1628 spin_unlock(&tty_files_lock);
1631 put_pid(tty->session);
1632 free_tty_struct(tty);
1635 static void queue_release_one_tty(struct kref *kref)
1637 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1639 /* The hangup queue is now free so we can reuse it rather than
1640 waste a chunk of memory for each port */
1641 INIT_WORK(&tty->hangup_work, release_one_tty);
1642 schedule_work(&tty->hangup_work);
1646 * tty_kref_put - release a tty kref
1649 * Release a reference to a tty device and if need be let the kref
1650 * layer destruct the object for us
1653 void tty_kref_put(struct tty_struct *tty)
1656 kref_put(&tty->kref, queue_release_one_tty);
1658 EXPORT_SYMBOL(tty_kref_put);
1661 * release_tty - release tty structure memory
1663 * Release both @tty and a possible linked partner (think pty pair),
1664 * and decrement the refcount of the backing module.
1668 * takes the file list lock internally when working on the list
1669 * of ttys that the driver keeps.
1672 static void release_tty(struct tty_struct *tty, int idx)
1674 /* This should always be true but check for the moment */
1675 WARN_ON(tty->index != idx);
1676 WARN_ON(!mutex_is_locked(&tty_mutex));
1677 if (tty->ops->shutdown)
1678 tty->ops->shutdown(tty);
1679 tty_free_termios(tty);
1680 tty_driver_remove_tty(tty->driver, tty);
1681 tty->port->itty = NULL;
1683 tty->link->port->itty = NULL;
1684 cancel_work_sync(&tty->port->buf.work);
1687 tty_kref_put(tty->link);
1692 * tty_release_checks - check a tty before real release
1693 * @tty: tty to check
1694 * @o_tty: link of @tty (if any)
1695 * @idx: index of the tty
1697 * Performs some paranoid checking before true release of the @tty.
1698 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1700 static int tty_release_checks(struct tty_struct *tty, struct tty_struct *o_tty,
1703 #ifdef TTY_PARANOIA_CHECK
1704 if (idx < 0 || idx >= tty->driver->num) {
1705 printk(KERN_DEBUG "%s: bad idx when trying to free (%s)\n",
1706 __func__, tty->name);
1710 /* not much to check for devpts */
1711 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1714 if (tty != tty->driver->ttys[idx]) {
1715 printk(KERN_DEBUG "%s: driver.table[%d] not tty for (%s)\n",
1716 __func__, idx, tty->name);
1719 if (tty->driver->other) {
1720 if (o_tty != tty->driver->other->ttys[idx]) {
1721 printk(KERN_DEBUG "%s: other->table[%d] not o_tty for (%s)\n",
1722 __func__, idx, tty->name);
1725 if (o_tty->link != tty) {
1726 printk(KERN_DEBUG "%s: bad pty pointers\n", __func__);
1735 * tty_release - vfs callback for close
1736 * @inode: inode of tty
1737 * @filp: file pointer for handle to tty
1739 * Called the last time each file handle is closed that references
1740 * this tty. There may however be several such references.
1743 * Takes bkl. See tty_release_dev
1745 * Even releasing the tty structures is a tricky business.. We have
1746 * to be very careful that the structures are all released at the
1747 * same time, as interrupts might otherwise get the wrong pointers.
1749 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1750 * lead to double frees or releasing memory still in use.
1753 int tty_release(struct inode *inode, struct file *filp)
1755 struct tty_struct *tty = file_tty(filp);
1756 struct tty_struct *o_tty;
1757 int pty_master, tty_closing, o_tty_closing, do_sleep;
1761 if (tty_paranoia_check(tty, inode, __func__))
1765 check_tty_count(tty, __func__);
1767 __tty_fasync(-1, filp, 0);
1770 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1771 tty->driver->subtype == PTY_TYPE_MASTER);
1772 /* Review: parallel close */
1775 if (tty_release_checks(tty, o_tty, idx)) {
1780 #ifdef TTY_DEBUG_HANGUP
1781 printk(KERN_DEBUG "%s: %s (tty count=%d)...\n", __func__,
1782 tty_name(tty, buf), tty->count);
1785 if (tty->ops->close)
1786 tty->ops->close(tty, filp);
1790 * Sanity check: if tty->count is going to zero, there shouldn't be
1791 * any waiters on tty->read_wait or tty->write_wait. We test the
1792 * wait queues and kick everyone out _before_ actually starting to
1793 * close. This ensures that we won't block while releasing the tty
1796 * The test for the o_tty closing is necessary, since the master and
1797 * slave sides may close in any order. If the slave side closes out
1798 * first, its count will be one, since the master side holds an open.
1799 * Thus this test wouldn't be triggered at the time the slave closes,
1802 tty_lock_pair(tty, o_tty);
1805 tty_closing = tty->count <= 1;
1806 o_tty_closing = o_tty &&
1807 (o_tty->count <= (pty_master ? 1 : 0));
1811 if (waitqueue_active(&tty->read_wait)) {
1812 wake_up_poll(&tty->read_wait, POLLIN);
1815 if (waitqueue_active(&tty->write_wait)) {
1816 wake_up_poll(&tty->write_wait, POLLOUT);
1820 if (o_tty_closing) {
1821 if (waitqueue_active(&o_tty->read_wait)) {
1822 wake_up_poll(&o_tty->read_wait, POLLIN);
1825 if (waitqueue_active(&o_tty->write_wait)) {
1826 wake_up_poll(&o_tty->write_wait, POLLOUT);
1833 printk(KERN_WARNING "%s: %s: read/write wait queue active!\n",
1834 __func__, tty_name(tty, buf));
1839 * The closing flags are now consistent with the open counts on
1840 * both sides, and we've completed the last operation that could
1841 * block, so it's safe to proceed with closing.
1843 * We must *not* drop the tty_mutex until we ensure that a further
1844 * entry into tty_open can not pick up this tty.
1847 if (--o_tty->count < 0) {
1848 printk(KERN_WARNING "%s: bad pty slave count (%d) for %s\n",
1849 __func__, o_tty->count, tty_name(o_tty, buf));
1853 if (--tty->count < 0) {
1854 printk(KERN_WARNING "%s: bad tty->count (%d) for %s\n",
1855 __func__, tty->count, tty_name(tty, buf));
1860 * We've decremented tty->count, so we need to remove this file
1861 * descriptor off the tty->tty_files list; this serves two
1863 * - check_tty_count sees the correct number of file descriptors
1864 * associated with this tty.
1865 * - do_tty_hangup no longer sees this file descriptor as
1866 * something that needs to be handled for hangups.
1871 * Perform some housekeeping before deciding whether to return.
1873 * If _either_ side is closing, make sure there aren't any
1874 * processes that still think tty or o_tty is their controlling
1877 if (tty_closing || o_tty_closing) {
1878 read_lock(&tasklist_lock);
1879 session_clear_tty(tty->session);
1881 session_clear_tty(o_tty->session);
1882 read_unlock(&tasklist_lock);
1885 tty_unlock_pair(tty, o_tty);
1886 /* At this point, the tty->count == 0 should ensure a dead tty
1887 cannot be re-opened by a racing opener */
1889 /* check whether both sides are closing ... */
1890 if (!tty_closing || (o_tty && !o_tty_closing))
1893 #ifdef TTY_DEBUG_HANGUP
1894 printk(KERN_DEBUG "%s: %s: final close\n", __func__, tty_name(tty, buf));
1897 * Ask the line discipline code to release its structures
1899 tty_ldisc_release(tty, o_tty);
1901 /* Wait for pending work before tty destruction commmences */
1902 tty_flush_works(tty);
1904 tty_flush_works(o_tty);
1906 #ifdef TTY_DEBUG_HANGUP
1907 printk(KERN_DEBUG "%s: %s: freeing structure...\n", __func__, tty_name(tty, buf));
1910 * The release_tty function takes care of the details of clearing
1911 * the slots and preserving the termios structure. The tty_unlock_pair
1912 * should be safe as we keep a kref while the tty is locked (so the
1913 * unlock never unlocks a freed tty).
1915 mutex_lock(&tty_mutex);
1916 release_tty(tty, idx);
1917 mutex_unlock(&tty_mutex);
1923 * tty_open_current_tty - get locked tty of current task
1924 * @device: device number
1925 * @filp: file pointer to tty
1926 * @return: locked tty of the current task iff @device is /dev/tty
1928 * Performs a re-open of the current task's controlling tty.
1930 * We cannot return driver and index like for the other nodes because
1931 * devpts will not work then. It expects inodes to be from devpts FS.
1933 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1935 struct tty_struct *tty;
1938 if (device != MKDEV(TTYAUX_MAJOR, 0))
1941 tty = get_current_tty();
1943 return ERR_PTR(-ENXIO);
1945 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1948 tty_kref_put(tty); /* safe to drop the kref now */
1950 retval = tty_reopen(tty);
1953 tty = ERR_PTR(retval);
1959 * tty_lookup_driver - lookup a tty driver for a given device file
1960 * @device: device number
1961 * @filp: file pointer to tty
1962 * @noctty: set if the device should not become a controlling tty
1963 * @index: index for the device in the @return driver
1964 * @return: driver for this inode (with increased refcount)
1966 * If @return is not erroneous, the caller is responsible to decrement the
1967 * refcount by tty_driver_kref_put.
1969 * Locking: tty_mutex protects get_tty_driver
1971 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1972 int *noctty, int *index)
1974 struct tty_driver *driver;
1978 case MKDEV(TTY_MAJOR, 0): {
1979 extern struct tty_driver *console_driver;
1980 driver = tty_driver_kref_get(console_driver);
1981 *index = fg_console;
1986 case MKDEV(TTYAUX_MAJOR, 1): {
1987 struct tty_driver *console_driver = console_device(index);
1988 if (console_driver) {
1989 driver = tty_driver_kref_get(console_driver);
1991 /* Don't let /dev/console block */
1992 filp->f_flags |= O_NONBLOCK;
1997 return ERR_PTR(-ENODEV);
2000 driver = get_tty_driver(device, index);
2002 return ERR_PTR(-ENODEV);
2009 * tty_open - open a tty device
2010 * @inode: inode of device file
2011 * @filp: file pointer to tty
2013 * tty_open and tty_release keep up the tty count that contains the
2014 * number of opens done on a tty. We cannot use the inode-count, as
2015 * different inodes might point to the same tty.
2017 * Open-counting is needed for pty masters, as well as for keeping
2018 * track of serial lines: DTR is dropped when the last close happens.
2019 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2021 * The termios state of a pty is reset on first open so that
2022 * settings don't persist across reuse.
2024 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
2025 * tty->count should protect the rest.
2026 * ->siglock protects ->signal/->sighand
2028 * Note: the tty_unlock/lock cases without a ref are only safe due to
2032 static int tty_open(struct inode *inode, struct file *filp)
2034 struct tty_struct *tty;
2036 struct tty_driver *driver = NULL;
2038 dev_t device = inode->i_rdev;
2039 unsigned saved_flags = filp->f_flags;
2041 nonseekable_open(inode, filp);
2044 retval = tty_alloc_file(filp);
2048 noctty = filp->f_flags & O_NOCTTY;
2052 tty = tty_open_current_tty(device, filp);
2054 mutex_lock(&tty_mutex);
2055 driver = tty_lookup_driver(device, filp, &noctty, &index);
2056 if (IS_ERR(driver)) {
2057 retval = PTR_ERR(driver);
2061 /* check whether we're reopening an existing tty */
2062 tty = tty_driver_lookup_tty(driver, inode, index);
2064 retval = PTR_ERR(tty);
2069 mutex_unlock(&tty_mutex);
2071 /* safe to drop the kref from tty_driver_lookup_tty() */
2073 retval = tty_reopen(tty);
2076 tty = ERR_PTR(retval);
2078 } else { /* Returns with the tty_lock held for now */
2079 tty = tty_init_dev(driver, index);
2080 mutex_unlock(&tty_mutex);
2083 tty_driver_kref_put(driver);
2087 retval = PTR_ERR(tty);
2091 tty_add_file(tty, filp);
2093 check_tty_count(tty, __func__);
2094 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2095 tty->driver->subtype == PTY_TYPE_MASTER)
2097 #ifdef TTY_DEBUG_HANGUP
2098 printk(KERN_DEBUG "%s: opening %s...\n", __func__, tty->name);
2101 retval = tty->ops->open(tty, filp);
2104 filp->f_flags = saved_flags;
2106 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
2107 !capable(CAP_SYS_ADMIN))
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 (filp->f_op == &hung_up_tty_fops)
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)))
2759 * if pty, return the slave side (real_tty)
2760 * otherwise, return self
2762 static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2764 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2765 tty->driver->subtype == PTY_TYPE_MASTER)
2771 * Split this up, as gcc can choke on it otherwise..
2773 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2775 struct tty_struct *tty = file_tty(file);
2776 struct tty_struct *real_tty;
2777 void __user *p = (void __user *)arg;
2779 struct tty_ldisc *ld;
2781 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2784 real_tty = tty_pair_get_tty(tty);
2787 * Factor out some common prep work
2795 retval = tty_check_change(tty);
2798 if (cmd != TIOCCBRK) {
2799 tty_wait_until_sent(tty, 0);
2800 if (signal_pending(current))
2811 return tiocsti(tty, p);
2813 return tiocgwinsz(real_tty, p);
2815 return tiocswinsz(real_tty, p);
2817 return real_tty != tty ? -EINVAL : tioccons(file);
2819 return fionbio(file, p);
2821 set_bit(TTY_EXCLUSIVE, &tty->flags);
2824 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2828 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2829 return put_user(excl, (int __user *)p);
2832 if (current->signal->tty != tty)
2837 return tiocsctty(tty, arg);
2839 return tiocgpgrp(tty, real_tty, p);
2841 return tiocspgrp(tty, real_tty, p);
2843 return tiocgsid(tty, real_tty, p);
2845 return put_user(tty->ldisc->ops->num, (int __user *)p);
2847 return tiocsetd(tty, p);
2849 if (!capable(CAP_SYS_ADMIN))
2855 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2856 return put_user(ret, (unsigned int __user *)p);
2861 case TIOCSBRK: /* Turn break on, unconditionally */
2862 if (tty->ops->break_ctl)
2863 return tty->ops->break_ctl(tty, -1);
2865 case TIOCCBRK: /* Turn break off, unconditionally */
2866 if (tty->ops->break_ctl)
2867 return tty->ops->break_ctl(tty, 0);
2869 case TCSBRK: /* SVID version: non-zero arg --> no break */
2870 /* non-zero arg means wait for all output data
2871 * to be sent (performed above) but don't send break.
2872 * This is used by the tcdrain() termios function.
2875 return send_break(tty, 250);
2877 case TCSBRKP: /* support for POSIX tcsendbreak() */
2878 return send_break(tty, arg ? arg*100 : 250);
2881 return tty_tiocmget(tty, p);
2885 return tty_tiocmset(tty, cmd, p);
2887 retval = tty_tiocgicount(tty, p);
2888 /* For the moment allow fall through to the old method */
2889 if (retval != -EINVAL)
2896 /* flush tty buffer and allow ldisc to process ioctl */
2897 tty_buffer_flush(tty);
2902 if (tty->ops->ioctl) {
2903 retval = (tty->ops->ioctl)(tty, cmd, arg);
2904 if (retval != -ENOIOCTLCMD)
2907 ld = tty_ldisc_ref_wait(tty);
2909 if (ld->ops->ioctl) {
2910 retval = ld->ops->ioctl(tty, file, cmd, arg);
2911 if (retval == -ENOIOCTLCMD)
2914 tty_ldisc_deref(ld);
2918 #ifdef CONFIG_COMPAT
2919 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2922 struct tty_struct *tty = file_tty(file);
2923 struct tty_ldisc *ld;
2924 int retval = -ENOIOCTLCMD;
2926 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2929 if (tty->ops->compat_ioctl) {
2930 retval = (tty->ops->compat_ioctl)(tty, cmd, arg);
2931 if (retval != -ENOIOCTLCMD)
2935 ld = tty_ldisc_ref_wait(tty);
2936 if (ld->ops->compat_ioctl)
2937 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2939 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
2940 tty_ldisc_deref(ld);
2946 static int this_tty(const void *t, struct file *file, unsigned fd)
2948 if (likely(file->f_op->read != tty_read))
2950 return file_tty(file) != t ? 0 : fd + 1;
2954 * This implements the "Secure Attention Key" --- the idea is to
2955 * prevent trojan horses by killing all processes associated with this
2956 * tty when the user hits the "Secure Attention Key". Required for
2957 * super-paranoid applications --- see the Orange Book for more details.
2959 * This code could be nicer; ideally it should send a HUP, wait a few
2960 * seconds, then send a INT, and then a KILL signal. But you then
2961 * have to coordinate with the init process, since all processes associated
2962 * with the current tty must be dead before the new getty is allowed
2965 * Now, if it would be correct ;-/ The current code has a nasty hole -
2966 * it doesn't catch files in flight. We may send the descriptor to ourselves
2967 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2969 * Nasty bug: do_SAK is being called in interrupt context. This can
2970 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2972 void __do_SAK(struct tty_struct *tty)
2977 struct task_struct *g, *p;
2978 struct pid *session;
2983 session = tty->session;
2985 tty_ldisc_flush(tty);
2987 tty_driver_flush_buffer(tty);
2989 read_lock(&tasklist_lock);
2990 /* Kill the entire session */
2991 do_each_pid_task(session, PIDTYPE_SID, p) {
2992 printk(KERN_NOTICE "SAK: killed process %d"
2993 " (%s): task_session(p)==tty->session\n",
2994 task_pid_nr(p), p->comm);
2995 send_sig(SIGKILL, p, 1);
2996 } while_each_pid_task(session, PIDTYPE_SID, p);
2997 /* Now kill any processes that happen to have the
3000 do_each_thread(g, p) {
3001 if (p->signal->tty == tty) {
3002 printk(KERN_NOTICE "SAK: killed process %d"
3003 " (%s): task_session(p)==tty->session\n",
3004 task_pid_nr(p), p->comm);
3005 send_sig(SIGKILL, p, 1);
3009 i = iterate_fd(p->files, 0, this_tty, tty);
3011 printk(KERN_NOTICE "SAK: killed process %d"
3012 " (%s): fd#%d opened to the tty\n",
3013 task_pid_nr(p), p->comm, i - 1);
3014 force_sig(SIGKILL, p);
3017 } while_each_thread(g, p);
3018 read_unlock(&tasklist_lock);
3022 static void do_SAK_work(struct work_struct *work)
3024 struct tty_struct *tty =
3025 container_of(work, struct tty_struct, SAK_work);
3030 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3031 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3032 * the values which we write to it will be identical to the values which it
3033 * already has. --akpm
3035 void do_SAK(struct tty_struct *tty)
3039 schedule_work(&tty->SAK_work);
3042 EXPORT_SYMBOL(do_SAK);
3044 static int dev_match_devt(struct device *dev, const void *data)
3046 const dev_t *devt = data;
3047 return dev->devt == *devt;
3050 /* Must put_device() after it's unused! */
3051 static struct device *tty_get_device(struct tty_struct *tty)
3053 dev_t devt = tty_devnum(tty);
3054 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
3061 * This subroutine allocates and initializes a tty structure.
3063 * Locking: none - tty in question is not exposed at this point
3066 struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
3068 struct tty_struct *tty;
3070 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
3074 kref_init(&tty->kref);
3075 tty->magic = TTY_MAGIC;
3076 tty_ldisc_init(tty);
3077 tty->session = NULL;
3079 mutex_init(&tty->legacy_mutex);
3080 mutex_init(&tty->throttle_mutex);
3081 init_rwsem(&tty->termios_rwsem);
3082 mutex_init(&tty->winsize_mutex);
3083 init_ldsem(&tty->ldisc_sem);
3084 init_waitqueue_head(&tty->write_wait);
3085 init_waitqueue_head(&tty->read_wait);
3086 INIT_WORK(&tty->hangup_work, do_tty_hangup);
3087 mutex_init(&tty->atomic_write_lock);
3088 spin_lock_init(&tty->ctrl_lock);
3089 spin_lock_init(&tty->flow_lock);
3090 INIT_LIST_HEAD(&tty->tty_files);
3091 INIT_WORK(&tty->SAK_work, do_SAK_work);
3093 tty->driver = driver;
3094 tty->ops = driver->ops;
3096 tty_line_name(driver, idx, tty->name);
3097 tty->dev = tty_get_device(tty);
3103 * deinitialize_tty_struct
3104 * @tty: tty to deinitialize
3106 * This subroutine deinitializes a tty structure that has been newly
3107 * allocated but tty_release cannot be called on that yet.
3109 * Locking: none - tty in question must not be exposed at this point
3111 void deinitialize_tty_struct(struct tty_struct *tty)
3113 tty_ldisc_deinit(tty);
3117 * tty_put_char - write one character to a tty
3121 * Write one byte to the tty using the provided put_char method
3122 * if present. Returns the number of characters successfully output.
3124 * Note: the specific put_char operation in the driver layer may go
3125 * away soon. Don't call it directly, use this method
3128 int tty_put_char(struct tty_struct *tty, unsigned char ch)
3130 if (tty->ops->put_char)
3131 return tty->ops->put_char(tty, ch);
3132 return tty->ops->write(tty, &ch, 1);
3134 EXPORT_SYMBOL_GPL(tty_put_char);
3136 struct class *tty_class;
3138 static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3139 unsigned int index, unsigned int count)
3141 /* init here, since reused cdevs cause crashes */
3142 cdev_init(&driver->cdevs[index], &tty_fops);
3143 driver->cdevs[index].owner = driver->owner;
3144 return cdev_add(&driver->cdevs[index], dev, count);
3148 * tty_register_device - register a tty device
3149 * @driver: the tty driver that describes the tty device
3150 * @index: the index in the tty driver for this tty device
3151 * @device: a struct device that is associated with this tty device.
3152 * This field is optional, if there is no known struct device
3153 * for this tty device it can be set to NULL safely.
3155 * Returns a pointer to the struct device for this tty device
3156 * (or ERR_PTR(-EFOO) on error).
3158 * This call is required to be made to register an individual tty device
3159 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3160 * that bit is not set, this function should not be called by a tty
3166 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3167 struct device *device)
3169 return tty_register_device_attr(driver, index, device, NULL, NULL);
3171 EXPORT_SYMBOL(tty_register_device);
3173 static void tty_device_create_release(struct device *dev)
3175 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3180 * tty_register_device_attr - register a tty device
3181 * @driver: the tty driver that describes the tty device
3182 * @index: the index in the tty driver for this tty device
3183 * @device: a struct device that is associated with this tty device.
3184 * This field is optional, if there is no known struct device
3185 * for this tty device it can be set to NULL safely.
3186 * @drvdata: Driver data to be set to device.
3187 * @attr_grp: Attribute group to be set on device.
3189 * Returns a pointer to the struct device for this tty device
3190 * (or ERR_PTR(-EFOO) on error).
3192 * This call is required to be made to register an individual tty device
3193 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3194 * that bit is not set, this function should not be called by a tty
3199 struct device *tty_register_device_attr(struct tty_driver *driver,
3200 unsigned index, struct device *device,
3202 const struct attribute_group **attr_grp)
3205 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3206 struct device *dev = NULL;
3207 int retval = -ENODEV;
3210 if (index >= driver->num) {
3211 printk(KERN_ERR "Attempt to register invalid tty line number "
3213 return ERR_PTR(-EINVAL);
3216 if (driver->type == TTY_DRIVER_TYPE_PTY)
3217 pty_line_name(driver, index, name);
3219 tty_line_name(driver, index, name);
3221 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3222 retval = tty_cdev_add(driver, devt, index, 1);
3228 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3235 dev->class = tty_class;
3236 dev->parent = device;
3237 dev->release = tty_device_create_release;
3238 dev_set_name(dev, "%s", name);
3239 dev->groups = attr_grp;
3240 dev_set_drvdata(dev, drvdata);
3242 retval = device_register(dev);
3251 cdev_del(&driver->cdevs[index]);
3252 return ERR_PTR(retval);
3254 EXPORT_SYMBOL_GPL(tty_register_device_attr);
3257 * tty_unregister_device - unregister a tty device
3258 * @driver: the tty driver that describes the tty device
3259 * @index: the index in the tty driver for this tty device
3261 * If a tty device is registered with a call to tty_register_device() then
3262 * this function must be called when the tty device is gone.
3267 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3269 device_destroy(tty_class,
3270 MKDEV(driver->major, driver->minor_start) + index);
3271 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC))
3272 cdev_del(&driver->cdevs[index]);
3274 EXPORT_SYMBOL(tty_unregister_device);
3277 * __tty_alloc_driver -- allocate tty driver
3278 * @lines: count of lines this driver can handle at most
3279 * @owner: module which is repsonsible for this driver
3280 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3282 * This should not be called directly, some of the provided macros should be
3283 * used instead. Use IS_ERR and friends on @retval.
3285 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3286 unsigned long flags)
3288 struct tty_driver *driver;
3289 unsigned int cdevs = 1;
3292 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3293 return ERR_PTR(-EINVAL);
3295 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3297 return ERR_PTR(-ENOMEM);
3299 kref_init(&driver->kref);
3300 driver->magic = TTY_DRIVER_MAGIC;
3301 driver->num = lines;
3302 driver->owner = owner;
3303 driver->flags = flags;
3305 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3306 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3308 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3310 if (!driver->ttys || !driver->termios) {
3316 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3317 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3319 if (!driver->ports) {
3326 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3327 if (!driver->cdevs) {
3334 kfree(driver->ports);
3335 kfree(driver->ttys);
3336 kfree(driver->termios);
3338 return ERR_PTR(err);
3340 EXPORT_SYMBOL(__tty_alloc_driver);
3342 static void destruct_tty_driver(struct kref *kref)
3344 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3346 struct ktermios *tp;
3348 if (driver->flags & TTY_DRIVER_INSTALLED) {
3350 * Free the termios and termios_locked structures because
3351 * we don't want to get memory leaks when modular tty
3352 * drivers are removed from the kernel.
3354 for (i = 0; i < driver->num; i++) {
3355 tp = driver->termios[i];
3357 driver->termios[i] = NULL;
3360 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3361 tty_unregister_device(driver, i);
3363 proc_tty_unregister_driver(driver);
3364 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3365 cdev_del(&driver->cdevs[0]);
3367 kfree(driver->cdevs);
3368 kfree(driver->ports);
3369 kfree(driver->termios);
3370 kfree(driver->ttys);
3374 void tty_driver_kref_put(struct tty_driver *driver)
3376 kref_put(&driver->kref, destruct_tty_driver);
3378 EXPORT_SYMBOL(tty_driver_kref_put);
3380 void tty_set_operations(struct tty_driver *driver,
3381 const struct tty_operations *op)
3385 EXPORT_SYMBOL(tty_set_operations);
3387 void put_tty_driver(struct tty_driver *d)
3389 tty_driver_kref_put(d);
3391 EXPORT_SYMBOL(put_tty_driver);
3394 * Called by a tty driver to register itself.
3396 int tty_register_driver(struct tty_driver *driver)
3403 if (!driver->major) {
3404 error = alloc_chrdev_region(&dev, driver->minor_start,
3405 driver->num, driver->name);
3407 driver->major = MAJOR(dev);
3408 driver->minor_start = MINOR(dev);
3411 dev = MKDEV(driver->major, driver->minor_start);
3412 error = register_chrdev_region(dev, driver->num, driver->name);
3417 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3418 error = tty_cdev_add(driver, dev, 0, driver->num);
3420 goto err_unreg_char;
3423 mutex_lock(&tty_mutex);
3424 list_add(&driver->tty_drivers, &tty_drivers);
3425 mutex_unlock(&tty_mutex);
3427 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3428 for (i = 0; i < driver->num; i++) {
3429 d = tty_register_device(driver, i, NULL);
3432 goto err_unreg_devs;
3436 proc_tty_register_driver(driver);
3437 driver->flags |= TTY_DRIVER_INSTALLED;
3441 for (i--; i >= 0; i--)
3442 tty_unregister_device(driver, i);
3444 mutex_lock(&tty_mutex);
3445 list_del(&driver->tty_drivers);
3446 mutex_unlock(&tty_mutex);
3449 unregister_chrdev_region(dev, driver->num);
3453 EXPORT_SYMBOL(tty_register_driver);
3456 * Called by a tty driver to unregister itself.
3458 int tty_unregister_driver(struct tty_driver *driver)
3462 if (driver->refcount)
3465 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3467 mutex_lock(&tty_mutex);
3468 list_del(&driver->tty_drivers);
3469 mutex_unlock(&tty_mutex);
3473 EXPORT_SYMBOL(tty_unregister_driver);
3475 dev_t tty_devnum(struct tty_struct *tty)
3477 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3479 EXPORT_SYMBOL(tty_devnum);
3481 void tty_default_fops(struct file_operations *fops)
3487 * Initialize the console device. This is called *early*, so
3488 * we can't necessarily depend on lots of kernel help here.
3489 * Just do some early initializations, and do the complex setup
3492 void __init console_init(void)
3496 /* Setup the default TTY line discipline. */
3500 * set up the console device so that later boot sequences can
3501 * inform about problems etc..
3503 call = __con_initcall_start;
3504 while (call < __con_initcall_end) {
3510 static char *tty_devnode(struct device *dev, umode_t *mode)
3514 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3515 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3520 static int __init tty_class_init(void)
3522 tty_class = class_create(THIS_MODULE, "tty");
3523 if (IS_ERR(tty_class))
3524 return PTR_ERR(tty_class);
3525 tty_class->devnode = tty_devnode;
3529 postcore_initcall(tty_class_init);
3531 /* 3/2004 jmc: why do these devices exist? */
3532 static struct cdev tty_cdev, console_cdev;
3534 static ssize_t show_cons_active(struct device *dev,
3535 struct device_attribute *attr, char *buf)
3537 struct console *cs[16];
3543 for_each_console(c) {
3548 if ((c->flags & CON_ENABLED) == 0)
3551 if (i >= ARRAY_SIZE(cs))
3555 int index = cs[i]->index;
3556 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3558 /* don't resolve tty0 as some programs depend on it */
3559 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3560 count += tty_line_name(drv, index, buf + count);
3562 count += sprintf(buf + count, "%s%d",
3563 cs[i]->name, cs[i]->index);
3565 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3571 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3573 static struct device *consdev;
3575 void console_sysfs_notify(void)
3578 sysfs_notify(&consdev->kobj, NULL, "active");
3582 * Ok, now we can initialize the rest of the tty devices and can count
3583 * on memory allocations, interrupts etc..
3585 int __init tty_init(void)
3587 cdev_init(&tty_cdev, &tty_fops);
3588 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3589 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3590 panic("Couldn't register /dev/tty driver\n");
3591 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3593 cdev_init(&console_cdev, &console_fops);
3594 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3595 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3596 panic("Couldn't register /dev/console driver\n");
3597 consdev = device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3599 if (IS_ERR(consdev))
3602 WARN_ON(device_create_file(consdev, &dev_attr_active) < 0);
3605 vty_init(&console_fops);