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 /* Caller must hold tty_lock */
279 static int check_tty_count(struct tty_struct *tty, const char *routine)
281 #ifdef CHECK_TTY_COUNT
285 spin_lock(&tty_files_lock);
286 list_for_each(p, &tty->tty_files) {
289 spin_unlock(&tty_files_lock);
290 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
291 tty->driver->subtype == PTY_TYPE_SLAVE &&
292 tty->link && tty->link->count)
294 if (tty->count != count) {
295 printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) "
296 "!= #fd's(%d) in %s\n",
297 tty->name, tty->count, count, routine);
305 * get_tty_driver - find device of a tty
306 * @dev_t: device identifier
307 * @index: returns the index of the tty
309 * This routine returns a tty driver structure, given a device number
310 * and also passes back the index number.
312 * Locking: caller must hold tty_mutex
315 static struct tty_driver *get_tty_driver(dev_t device, int *index)
317 struct tty_driver *p;
319 list_for_each_entry(p, &tty_drivers, tty_drivers) {
320 dev_t base = MKDEV(p->major, p->minor_start);
321 if (device < base || device >= base + p->num)
323 *index = device - base;
324 return tty_driver_kref_get(p);
329 #ifdef CONFIG_CONSOLE_POLL
332 * tty_find_polling_driver - find device of a polled tty
333 * @name: name string to match
334 * @line: pointer to resulting tty line nr
336 * This routine returns a tty driver structure, given a name
337 * and the condition that the tty driver is capable of polled
340 struct tty_driver *tty_find_polling_driver(char *name, int *line)
342 struct tty_driver *p, *res = NULL;
347 for (str = name; *str; str++)
348 if ((*str >= '0' && *str <= '9') || *str == ',')
354 tty_line = simple_strtoul(str, &str, 10);
356 mutex_lock(&tty_mutex);
357 /* Search through the tty devices to look for a match */
358 list_for_each_entry(p, &tty_drivers, tty_drivers) {
359 if (strncmp(name, p->name, len) != 0)
367 if (tty_line >= 0 && tty_line < p->num && p->ops &&
368 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
369 res = tty_driver_kref_get(p);
374 mutex_unlock(&tty_mutex);
378 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
382 * tty_check_change - check for POSIX terminal changes
385 * If we try to write to, or set the state of, a terminal and we're
386 * not in the foreground, send a SIGTTOU. If the signal is blocked or
387 * ignored, go ahead and perform the operation. (POSIX 7.2)
392 int tty_check_change(struct tty_struct *tty)
397 if (current->signal->tty != tty)
400 spin_lock_irqsave(&tty->ctrl_lock, flags);
403 printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
406 if (task_pgrp(current) == tty->pgrp)
408 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
409 if (is_ignored(SIGTTOU))
411 if (is_current_pgrp_orphaned()) {
415 kill_pgrp(task_pgrp(current), SIGTTOU, 1);
416 set_thread_flag(TIF_SIGPENDING);
421 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
425 EXPORT_SYMBOL(tty_check_change);
427 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
428 size_t count, loff_t *ppos)
433 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
434 size_t count, loff_t *ppos)
439 /* No kernel lock held - none needed ;) */
440 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
442 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
445 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
448 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
451 static long hung_up_tty_compat_ioctl(struct file *file,
452 unsigned int cmd, unsigned long arg)
454 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
457 static const struct file_operations tty_fops = {
462 .unlocked_ioctl = tty_ioctl,
463 .compat_ioctl = tty_compat_ioctl,
465 .release = tty_release,
466 .fasync = tty_fasync,
469 static const struct file_operations console_fops = {
472 .write = redirected_tty_write,
474 .unlocked_ioctl = tty_ioctl,
475 .compat_ioctl = tty_compat_ioctl,
477 .release = tty_release,
478 .fasync = tty_fasync,
481 static const struct file_operations hung_up_tty_fops = {
483 .read = hung_up_tty_read,
484 .write = hung_up_tty_write,
485 .poll = hung_up_tty_poll,
486 .unlocked_ioctl = hung_up_tty_ioctl,
487 .compat_ioctl = hung_up_tty_compat_ioctl,
488 .release = tty_release,
491 static DEFINE_SPINLOCK(redirect_lock);
492 static struct file *redirect;
495 void proc_clear_tty(struct task_struct *p)
498 struct tty_struct *tty;
499 spin_lock_irqsave(&p->sighand->siglock, flags);
500 tty = p->signal->tty;
501 p->signal->tty = NULL;
502 spin_unlock_irqrestore(&p->sighand->siglock, flags);
507 * proc_set_tty - set the controlling terminal
509 * Only callable by the session leader and only if it does not already have
510 * a controlling terminal.
512 * Caller must hold: tty_lock()
513 * a readlock on tasklist_lock
516 static void __proc_set_tty(struct tty_struct *tty)
520 spin_lock_irqsave(&tty->ctrl_lock, flags);
522 * The session and fg pgrp references will be non-NULL if
523 * tiocsctty() is stealing the controlling tty
525 put_pid(tty->session);
527 tty->pgrp = get_pid(task_pgrp(current));
528 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
529 tty->session = get_pid(task_session(current));
530 if (current->signal->tty) {
531 printk(KERN_DEBUG "tty not NULL!!\n");
532 tty_kref_put(current->signal->tty);
534 put_pid(current->signal->tty_old_pgrp);
535 current->signal->tty = tty_kref_get(tty);
536 current->signal->tty_old_pgrp = NULL;
539 static void proc_set_tty(struct tty_struct *tty)
541 spin_lock_irq(¤t->sighand->siglock);
543 spin_unlock_irq(¤t->sighand->siglock);
546 struct tty_struct *get_current_tty(void)
548 struct tty_struct *tty;
551 spin_lock_irqsave(¤t->sighand->siglock, flags);
552 tty = tty_kref_get(current->signal->tty);
553 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
556 EXPORT_SYMBOL_GPL(get_current_tty);
558 static void session_clear_tty(struct pid *session)
560 struct task_struct *p;
561 do_each_pid_task(session, PIDTYPE_SID, p) {
563 } while_each_pid_task(session, PIDTYPE_SID, p);
567 * tty_wakeup - request more data
570 * Internal and external helper for wakeups of tty. This function
571 * informs the line discipline if present that the driver is ready
572 * to receive more output data.
575 void tty_wakeup(struct tty_struct *tty)
577 struct tty_ldisc *ld;
579 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
580 ld = tty_ldisc_ref(tty);
582 if (ld->ops->write_wakeup)
583 ld->ops->write_wakeup(tty);
587 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
590 EXPORT_SYMBOL_GPL(tty_wakeup);
593 * tty_signal_session_leader - sends SIGHUP to session leader
594 * @tty controlling tty
595 * @exit_session if non-zero, signal all foreground group processes
597 * Send SIGHUP and SIGCONT to the session leader and its process group.
598 * Optionally, signal all processes in the foreground process group.
600 * Returns the number of processes in the session with this tty
601 * as their controlling terminal. This value is used to drop
602 * tty references for those processes.
604 static int tty_signal_session_leader(struct tty_struct *tty, int exit_session)
606 struct task_struct *p;
608 struct pid *tty_pgrp = NULL;
610 read_lock(&tasklist_lock);
612 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
613 spin_lock_irq(&p->sighand->siglock);
614 if (p->signal->tty == tty) {
615 p->signal->tty = NULL;
616 /* We defer the dereferences outside fo
620 if (!p->signal->leader) {
621 spin_unlock_irq(&p->sighand->siglock);
624 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
625 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
626 put_pid(p->signal->tty_old_pgrp); /* A noop */
627 spin_lock(&tty->ctrl_lock);
628 tty_pgrp = get_pid(tty->pgrp);
630 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
631 spin_unlock(&tty->ctrl_lock);
632 spin_unlock_irq(&p->sighand->siglock);
633 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
635 read_unlock(&tasklist_lock);
639 kill_pgrp(tty_pgrp, SIGHUP, exit_session);
647 * __tty_hangup - actual handler for hangup events
650 * This can be called by a "kworker" kernel thread. That is process
651 * synchronous but doesn't hold any locks, so we need to make sure we
652 * have the appropriate locks for what we're doing.
654 * The hangup event clears any pending redirections onto the hung up
655 * device. It ensures future writes will error and it does the needed
656 * line discipline hangup and signal delivery. The tty object itself
661 * redirect lock for undoing redirection
662 * file list lock for manipulating list of ttys
663 * tty_ldiscs_lock from called functions
664 * termios_rwsem resetting termios data
665 * tasklist_lock to walk task list for hangup event
666 * ->siglock to protect ->signal/->sighand
668 static void __tty_hangup(struct tty_struct *tty, int exit_session)
670 struct file *cons_filp = NULL;
671 struct file *filp, *f = NULL;
672 struct tty_file_private *priv;
673 int closecount = 0, n;
680 spin_lock(&redirect_lock);
681 if (redirect && file_tty(redirect) == tty) {
685 spin_unlock(&redirect_lock);
689 if (test_bit(TTY_HUPPED, &tty->flags)) {
694 /* inuse_filps is protected by the single tty lock,
695 this really needs to change if we want to flush the
696 workqueue with the lock held */
697 check_tty_count(tty, "tty_hangup");
699 spin_lock(&tty_files_lock);
700 /* This breaks for file handles being sent over AF_UNIX sockets ? */
701 list_for_each_entry(priv, &tty->tty_files, list) {
703 if (filp->f_op->write == redirected_tty_write)
705 if (filp->f_op->write != tty_write)
708 __tty_fasync(-1, filp, 0); /* can't block */
709 filp->f_op = &hung_up_tty_fops;
711 spin_unlock(&tty_files_lock);
713 refs = tty_signal_session_leader(tty, exit_session);
714 /* Account for the p->signal references we killed */
718 tty_ldisc_hangup(tty);
720 spin_lock_irq(&tty->ctrl_lock);
721 clear_bit(TTY_THROTTLED, &tty->flags);
722 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
723 put_pid(tty->session);
727 tty->ctrl_status = 0;
728 spin_unlock_irq(&tty->ctrl_lock);
731 * If one of the devices matches a console pointer, we
732 * cannot just call hangup() because that will cause
733 * tty->count and state->count to go out of sync.
734 * So we just call close() the right number of times.
738 for (n = 0; n < closecount; n++)
739 tty->ops->close(tty, cons_filp);
740 } else if (tty->ops->hangup)
741 tty->ops->hangup(tty);
743 * We don't want to have driver/ldisc interactions beyond
744 * the ones we did here. The driver layer expects no
745 * calls after ->hangup() from the ldisc side. However we
746 * can't yet guarantee all that.
748 set_bit(TTY_HUPPED, &tty->flags);
755 static void do_tty_hangup(struct work_struct *work)
757 struct tty_struct *tty =
758 container_of(work, struct tty_struct, hangup_work);
760 __tty_hangup(tty, 0);
764 * tty_hangup - trigger a hangup event
765 * @tty: tty to hangup
767 * A carrier loss (virtual or otherwise) has occurred on this like
768 * schedule a hangup sequence to run after this event.
771 void tty_hangup(struct tty_struct *tty)
773 #ifdef TTY_DEBUG_HANGUP
775 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
777 schedule_work(&tty->hangup_work);
780 EXPORT_SYMBOL(tty_hangup);
783 * tty_vhangup - process vhangup
784 * @tty: tty to hangup
786 * The user has asked via system call for the terminal to be hung up.
787 * We do this synchronously so that when the syscall returns the process
788 * is complete. That guarantee is necessary for security reasons.
791 void tty_vhangup(struct tty_struct *tty)
793 #ifdef TTY_DEBUG_HANGUP
796 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
798 __tty_hangup(tty, 0);
801 EXPORT_SYMBOL(tty_vhangup);
805 * tty_vhangup_self - process vhangup for own ctty
807 * Perform a vhangup on the current controlling tty
810 void tty_vhangup_self(void)
812 struct tty_struct *tty;
814 tty = get_current_tty();
822 * tty_vhangup_session - hangup session leader exit
823 * @tty: tty to hangup
825 * The session leader is exiting and hanging up its controlling terminal.
826 * Every process in the foreground process group is signalled SIGHUP.
828 * We do this synchronously so that when the syscall returns the process
829 * is complete. That guarantee is necessary for security reasons.
832 static void tty_vhangup_session(struct tty_struct *tty)
834 #ifdef TTY_DEBUG_HANGUP
837 printk(KERN_DEBUG "%s vhangup session...\n", tty_name(tty, buf));
839 __tty_hangup(tty, 1);
843 * tty_hung_up_p - was tty hung up
844 * @filp: file pointer of tty
846 * Return true if the tty has been subject to a vhangup or a carrier
850 int tty_hung_up_p(struct file *filp)
852 return (filp->f_op == &hung_up_tty_fops);
855 EXPORT_SYMBOL(tty_hung_up_p);
858 * disassociate_ctty - disconnect controlling tty
859 * @on_exit: true if exiting so need to "hang up" the session
861 * This function is typically called only by the session leader, when
862 * it wants to disassociate itself from its controlling tty.
864 * It performs the following functions:
865 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
866 * (2) Clears the tty from being controlling the session
867 * (3) Clears the controlling tty for all processes in the
870 * The argument on_exit is set to 1 if called when a process is
871 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
874 * BTM is taken for hysterical raisins, and held when
875 * called from no_tty().
876 * tty_mutex is taken to protect tty
877 * ->siglock is taken to protect ->signal/->sighand
878 * tasklist_lock is taken to walk process list for sessions
879 * ->siglock is taken to protect ->signal/->sighand
882 void disassociate_ctty(int on_exit)
884 struct tty_struct *tty;
886 if (!current->signal->leader)
889 tty = get_current_tty();
891 if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) {
892 tty_vhangup_session(tty);
894 struct pid *tty_pgrp = tty_get_pgrp(tty);
896 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
898 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
904 } else if (on_exit) {
905 struct pid *old_pgrp;
906 spin_lock_irq(¤t->sighand->siglock);
907 old_pgrp = current->signal->tty_old_pgrp;
908 current->signal->tty_old_pgrp = NULL;
909 spin_unlock_irq(¤t->sighand->siglock);
911 kill_pgrp(old_pgrp, SIGHUP, on_exit);
912 kill_pgrp(old_pgrp, SIGCONT, on_exit);
918 spin_lock_irq(¤t->sighand->siglock);
919 put_pid(current->signal->tty_old_pgrp);
920 current->signal->tty_old_pgrp = NULL;
922 tty = tty_kref_get(current->signal->tty);
925 spin_lock_irqsave(&tty->ctrl_lock, flags);
926 put_pid(tty->session);
930 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
933 #ifdef TTY_DEBUG_HANGUP
934 printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
939 spin_unlock_irq(¤t->sighand->siglock);
940 /* Now clear signal->tty under the lock */
941 read_lock(&tasklist_lock);
942 session_clear_tty(task_session(current));
943 read_unlock(&tasklist_lock);
948 * no_tty - Ensure the current process does not have a controlling tty
952 /* FIXME: Review locking here. The tty_lock never covered any race
953 between a new association and proc_clear_tty but possible we need
954 to protect against this anyway */
955 struct task_struct *tsk = current;
956 disassociate_ctty(0);
962 * stop_tty - propagate flow control
965 * Perform flow control to the driver. May be called
966 * on an already stopped device and will not re-call the driver
969 * This functionality is used by both the line disciplines for
970 * halting incoming flow and by the driver. It may therefore be
971 * called from any context, may be under the tty atomic_write_lock
978 void __stop_tty(struct tty_struct *tty)
984 (tty->ops->stop)(tty);
987 void stop_tty(struct tty_struct *tty)
991 spin_lock_irqsave(&tty->flow_lock, flags);
993 spin_unlock_irqrestore(&tty->flow_lock, flags);
995 EXPORT_SYMBOL(stop_tty);
998 * start_tty - propagate flow control
1001 * Start a tty that has been stopped if at all possible. If this
1002 * tty was previous stopped and is now being started, the driver
1003 * start method is invoked and the line discipline woken.
1009 void __start_tty(struct tty_struct *tty)
1011 if (!tty->stopped || tty->flow_stopped)
1014 if (tty->ops->start)
1015 (tty->ops->start)(tty);
1019 void start_tty(struct tty_struct *tty)
1021 unsigned long flags;
1023 spin_lock_irqsave(&tty->flow_lock, flags);
1025 spin_unlock_irqrestore(&tty->flow_lock, flags);
1027 EXPORT_SYMBOL(start_tty);
1029 /* We limit tty time update visibility to every 8 seconds or so. */
1030 static void tty_update_time(struct timespec *time)
1032 unsigned long sec = get_seconds() & ~7;
1033 if ((long)(sec - time->tv_sec) > 0)
1038 * tty_read - read method for tty device files
1039 * @file: pointer to tty file
1041 * @count: size of user buffer
1044 * Perform the read system call function on this terminal device. Checks
1045 * for hung up devices before calling the line discipline method.
1048 * Locks the line discipline internally while needed. Multiple
1049 * read calls may be outstanding in parallel.
1052 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
1056 struct inode *inode = file_inode(file);
1057 struct tty_struct *tty = file_tty(file);
1058 struct tty_ldisc *ld;
1060 if (tty_paranoia_check(tty, inode, "tty_read"))
1062 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
1065 /* We want to wait for the line discipline to sort out in this
1067 ld = tty_ldisc_ref_wait(tty);
1069 i = (ld->ops->read)(tty, file, buf, count);
1072 tty_ldisc_deref(ld);
1075 tty_update_time(&inode->i_atime);
1080 static void tty_write_unlock(struct tty_struct *tty)
1082 mutex_unlock(&tty->atomic_write_lock);
1083 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
1086 static int tty_write_lock(struct tty_struct *tty, int ndelay)
1088 if (!mutex_trylock(&tty->atomic_write_lock)) {
1091 if (mutex_lock_interruptible(&tty->atomic_write_lock))
1092 return -ERESTARTSYS;
1098 * Split writes up in sane blocksizes to avoid
1099 * denial-of-service type attacks
1101 static inline ssize_t do_tty_write(
1102 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
1103 struct tty_struct *tty,
1105 const char __user *buf,
1108 ssize_t ret, written = 0;
1111 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
1116 * We chunk up writes into a temporary buffer. This
1117 * simplifies low-level drivers immensely, since they
1118 * don't have locking issues and user mode accesses.
1120 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1123 * The default chunk-size is 2kB, because the NTTY
1124 * layer has problems with bigger chunks. It will
1125 * claim to be able to handle more characters than
1128 * FIXME: This can probably go away now except that 64K chunks
1129 * are too likely to fail unless switched to vmalloc...
1132 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1137 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1138 if (tty->write_cnt < chunk) {
1139 unsigned char *buf_chunk;
1144 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1149 kfree(tty->write_buf);
1150 tty->write_cnt = chunk;
1151 tty->write_buf = buf_chunk;
1154 /* Do the write .. */
1156 size_t size = count;
1160 if (copy_from_user(tty->write_buf, buf, size))
1162 ret = write(tty, file, tty->write_buf, size);
1171 if (signal_pending(current))
1176 tty_update_time(&file_inode(file)->i_mtime);
1180 tty_write_unlock(tty);
1185 * tty_write_message - write a message to a certain tty, not just the console.
1186 * @tty: the destination tty_struct
1187 * @msg: the message to write
1189 * This is used for messages that need to be redirected to a specific tty.
1190 * We don't put it into the syslog queue right now maybe in the future if
1193 * We must still hold the BTM and test the CLOSING flag for the moment.
1196 void tty_write_message(struct tty_struct *tty, char *msg)
1199 mutex_lock(&tty->atomic_write_lock);
1201 if (tty->ops->write && tty->count > 0) {
1203 tty->ops->write(tty, msg, strlen(msg));
1206 tty_write_unlock(tty);
1213 * tty_write - write method for tty device file
1214 * @file: tty file pointer
1215 * @buf: user data to write
1216 * @count: bytes to write
1219 * Write data to a tty device via the line discipline.
1222 * Locks the line discipline as required
1223 * Writes to the tty driver are serialized by the atomic_write_lock
1224 * and are then processed in chunks to the device. The line discipline
1225 * write method will not be invoked in parallel for each device.
1228 static ssize_t tty_write(struct file *file, const char __user *buf,
1229 size_t count, loff_t *ppos)
1231 struct tty_struct *tty = file_tty(file);
1232 struct tty_ldisc *ld;
1235 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1237 if (!tty || !tty->ops->write ||
1238 (test_bit(TTY_IO_ERROR, &tty->flags)))
1240 /* Short term debug to catch buggy drivers */
1241 if (tty->ops->write_room == NULL)
1242 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1244 ld = tty_ldisc_ref_wait(tty);
1245 if (!ld->ops->write)
1248 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1249 tty_ldisc_deref(ld);
1253 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1254 size_t count, loff_t *ppos)
1256 struct file *p = NULL;
1258 spin_lock(&redirect_lock);
1260 p = get_file(redirect);
1261 spin_unlock(&redirect_lock);
1265 res = vfs_write(p, buf, count, &p->f_pos);
1269 return tty_write(file, buf, count, ppos);
1273 * tty_send_xchar - send priority character
1275 * Send a high priority character to the tty even if stopped
1277 * Locking: none for xchar method, write ordering for write method.
1280 int tty_send_xchar(struct tty_struct *tty, char ch)
1282 int was_stopped = tty->stopped;
1284 if (tty->ops->send_xchar) {
1285 tty->ops->send_xchar(tty, ch);
1289 if (tty_write_lock(tty, 0) < 0)
1290 return -ERESTARTSYS;
1294 tty->ops->write(tty, &ch, 1);
1297 tty_write_unlock(tty);
1301 static char ptychar[] = "pqrstuvwxyzabcde";
1304 * pty_line_name - generate name for a pty
1305 * @driver: the tty driver in use
1306 * @index: the minor number
1307 * @p: output buffer of at least 6 bytes
1309 * Generate a name from a driver reference and write it to the output
1314 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1316 int i = index + driver->name_base;
1317 /* ->name is initialized to "ttyp", but "tty" is expected */
1318 sprintf(p, "%s%c%x",
1319 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1320 ptychar[i >> 4 & 0xf], i & 0xf);
1324 * tty_line_name - generate name for a tty
1325 * @driver: the tty driver in use
1326 * @index: the minor number
1327 * @p: output buffer of at least 7 bytes
1329 * Generate a name from a driver reference and write it to the output
1334 static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1336 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1337 return sprintf(p, "%s", driver->name);
1339 return sprintf(p, "%s%d", driver->name,
1340 index + driver->name_base);
1344 * tty_driver_lookup_tty() - find an existing tty, if any
1345 * @driver: the driver for the tty
1346 * @idx: the minor number
1348 * Return the tty, if found. If not found, return NULL or ERR_PTR() if the
1349 * driver lookup() method returns an error.
1351 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1353 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1354 struct inode *inode, int idx)
1356 struct tty_struct *tty;
1358 if (driver->ops->lookup)
1359 tty = driver->ops->lookup(driver, inode, idx);
1361 tty = driver->ttys[idx];
1369 * tty_init_termios - helper for termios setup
1370 * @tty: the tty to set up
1372 * Initialise the termios structures for this tty. Thus runs under
1373 * the tty_mutex currently so we can be relaxed about ordering.
1376 int tty_init_termios(struct tty_struct *tty)
1378 struct ktermios *tp;
1379 int idx = tty->index;
1381 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1382 tty->termios = tty->driver->init_termios;
1384 /* Check for lazy saved data */
1385 tp = tty->driver->termios[idx];
1389 tty->termios = tty->driver->init_termios;
1391 /* Compatibility until drivers always set this */
1392 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1393 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1396 EXPORT_SYMBOL_GPL(tty_init_termios);
1398 int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1400 int ret = tty_init_termios(tty);
1404 tty_driver_kref_get(driver);
1406 driver->ttys[tty->index] = tty;
1409 EXPORT_SYMBOL_GPL(tty_standard_install);
1412 * tty_driver_install_tty() - install a tty entry in the driver
1413 * @driver: the driver for the tty
1416 * Install a tty object into the driver tables. The tty->index field
1417 * will be set by the time this is called. This method is responsible
1418 * for ensuring any need additional structures are allocated and
1421 * Locking: tty_mutex for now
1423 static int tty_driver_install_tty(struct tty_driver *driver,
1424 struct tty_struct *tty)
1426 return driver->ops->install ? driver->ops->install(driver, tty) :
1427 tty_standard_install(driver, tty);
1431 * tty_driver_remove_tty() - remove a tty from the driver tables
1432 * @driver: the driver for the tty
1433 * @idx: the minor number
1435 * Remvoe a tty object from the driver tables. The tty->index field
1436 * will be set by the time this is called.
1438 * Locking: tty_mutex for now
1440 void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1442 if (driver->ops->remove)
1443 driver->ops->remove(driver, tty);
1445 driver->ttys[tty->index] = NULL;
1449 * tty_reopen() - fast re-open of an open tty
1450 * @tty - the tty to open
1452 * Return 0 on success, -errno on error.
1453 * Re-opens on master ptys are not allowed and return -EIO.
1455 * Locking: Caller must hold tty_lock
1457 static int tty_reopen(struct tty_struct *tty)
1459 struct tty_driver *driver = tty->driver;
1464 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1465 driver->subtype == PTY_TYPE_MASTER)
1470 WARN_ON(!tty->ldisc);
1476 * tty_init_dev - initialise a tty device
1477 * @driver: tty driver we are opening a device on
1478 * @idx: device index
1479 * @ret_tty: returned tty structure
1481 * Prepare a tty device. This may not be a "new" clean device but
1482 * could also be an active device. The pty drivers require special
1483 * handling because of this.
1486 * The function is called under the tty_mutex, which
1487 * protects us from the tty struct or driver itself going away.
1489 * On exit the tty device has the line discipline attached and
1490 * a reference count of 1. If a pair was created for pty/tty use
1491 * and the other was a pty master then it too has a reference count of 1.
1493 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1494 * failed open. The new code protects the open with a mutex, so it's
1495 * really quite straightforward. The mutex locking can probably be
1496 * relaxed for the (most common) case of reopening a tty.
1499 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1501 struct tty_struct *tty;
1505 * First time open is complex, especially for PTY devices.
1506 * This code guarantees that either everything succeeds and the
1507 * TTY is ready for operation, or else the table slots are vacated
1508 * and the allocated memory released. (Except that the termios
1509 * and locked termios may be retained.)
1512 if (!try_module_get(driver->owner))
1513 return ERR_PTR(-ENODEV);
1515 tty = alloc_tty_struct(driver, idx);
1518 goto err_module_put;
1522 retval = tty_driver_install_tty(driver, tty);
1524 goto err_deinit_tty;
1527 tty->port = driver->ports[idx];
1529 WARN_RATELIMIT(!tty->port,
1530 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1531 __func__, tty->driver->name);
1533 tty->port->itty = tty;
1536 * Structures all installed ... call the ldisc open routines.
1537 * If we fail here just call release_tty to clean up. No need
1538 * to decrement the use counts, as release_tty doesn't care.
1540 retval = tty_ldisc_setup(tty, tty->link);
1542 goto err_release_tty;
1543 /* Return the tty locked so that it cannot vanish under the caller */
1548 deinitialize_tty_struct(tty);
1549 free_tty_struct(tty);
1551 module_put(driver->owner);
1552 return ERR_PTR(retval);
1554 /* call the tty release_tty routine to clean out this slot */
1557 printk_ratelimited(KERN_INFO "tty_init_dev: ldisc open failed, "
1558 "clearing slot %d\n", idx);
1559 release_tty(tty, idx);
1560 return ERR_PTR(retval);
1563 void tty_free_termios(struct tty_struct *tty)
1565 struct ktermios *tp;
1566 int idx = tty->index;
1568 /* If the port is going to reset then it has no termios to save */
1569 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1572 /* Stash the termios data */
1573 tp = tty->driver->termios[idx];
1575 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1577 pr_warn("tty: no memory to save termios state.\n");
1580 tty->driver->termios[idx] = tp;
1584 EXPORT_SYMBOL(tty_free_termios);
1587 * tty_flush_works - flush all works of a tty
1588 * @tty: tty device to flush works for
1590 * Sync flush all works belonging to @tty.
1592 static void tty_flush_works(struct tty_struct *tty)
1594 flush_work(&tty->SAK_work);
1595 flush_work(&tty->hangup_work);
1599 * release_one_tty - release tty structure memory
1600 * @kref: kref of tty we are obliterating
1602 * Releases memory associated with a tty structure, and clears out the
1603 * driver table slots. This function is called when a device is no longer
1604 * in use. It also gets called when setup of a device fails.
1607 * takes the file list lock internally when working on the list
1608 * of ttys that the driver keeps.
1610 * This method gets called from a work queue so that the driver private
1611 * cleanup ops can sleep (needed for USB at least)
1613 static void release_one_tty(struct work_struct *work)
1615 struct tty_struct *tty =
1616 container_of(work, struct tty_struct, hangup_work);
1617 struct tty_driver *driver = tty->driver;
1618 struct module *owner = driver->owner;
1620 if (tty->ops->cleanup)
1621 tty->ops->cleanup(tty);
1624 tty_driver_kref_put(driver);
1627 spin_lock(&tty_files_lock);
1628 list_del_init(&tty->tty_files);
1629 spin_unlock(&tty_files_lock);
1632 put_pid(tty->session);
1633 free_tty_struct(tty);
1636 static void queue_release_one_tty(struct kref *kref)
1638 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1640 /* The hangup queue is now free so we can reuse it rather than
1641 waste a chunk of memory for each port */
1642 INIT_WORK(&tty->hangup_work, release_one_tty);
1643 schedule_work(&tty->hangup_work);
1647 * tty_kref_put - release a tty kref
1650 * Release a reference to a tty device and if need be let the kref
1651 * layer destruct the object for us
1654 void tty_kref_put(struct tty_struct *tty)
1657 kref_put(&tty->kref, queue_release_one_tty);
1659 EXPORT_SYMBOL(tty_kref_put);
1662 * release_tty - release tty structure memory
1664 * Release both @tty and a possible linked partner (think pty pair),
1665 * and decrement the refcount of the backing module.
1669 * takes the file list lock internally when working on the list
1670 * of ttys that the driver keeps.
1673 static void release_tty(struct tty_struct *tty, int idx)
1675 /* This should always be true but check for the moment */
1676 WARN_ON(tty->index != idx);
1677 WARN_ON(!mutex_is_locked(&tty_mutex));
1678 if (tty->ops->shutdown)
1679 tty->ops->shutdown(tty);
1680 tty_free_termios(tty);
1681 tty_driver_remove_tty(tty->driver, tty);
1682 tty->port->itty = NULL;
1684 tty->link->port->itty = NULL;
1685 cancel_work_sync(&tty->port->buf.work);
1688 tty_kref_put(tty->link);
1693 * tty_release_checks - check a tty before real release
1694 * @tty: tty to check
1695 * @o_tty: link of @tty (if any)
1696 * @idx: index of the tty
1698 * Performs some paranoid checking before true release of the @tty.
1699 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1701 static int tty_release_checks(struct tty_struct *tty, struct tty_struct *o_tty,
1704 #ifdef TTY_PARANOIA_CHECK
1705 if (idx < 0 || idx >= tty->driver->num) {
1706 printk(KERN_DEBUG "%s: bad idx when trying to free (%s)\n",
1707 __func__, tty->name);
1711 /* not much to check for devpts */
1712 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1715 if (tty != tty->driver->ttys[idx]) {
1716 printk(KERN_DEBUG "%s: driver.table[%d] not tty for (%s)\n",
1717 __func__, idx, tty->name);
1720 if (tty->driver->other) {
1721 if (o_tty != tty->driver->other->ttys[idx]) {
1722 printk(KERN_DEBUG "%s: other->table[%d] not o_tty for (%s)\n",
1723 __func__, idx, tty->name);
1726 if (o_tty->link != tty) {
1727 printk(KERN_DEBUG "%s: bad pty pointers\n", __func__);
1736 * tty_release - vfs callback for close
1737 * @inode: inode of tty
1738 * @filp: file pointer for handle to tty
1740 * Called the last time each file handle is closed that references
1741 * this tty. There may however be several such references.
1744 * Takes bkl. See tty_release_dev
1746 * Even releasing the tty structures is a tricky business.. We have
1747 * to be very careful that the structures are all released at the
1748 * same time, as interrupts might otherwise get the wrong pointers.
1750 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1751 * lead to double frees or releasing memory still in use.
1754 int tty_release(struct inode *inode, struct file *filp)
1756 struct tty_struct *tty = file_tty(filp);
1757 struct tty_struct *o_tty;
1758 int pty_master, tty_closing, o_tty_closing, do_sleep;
1762 if (tty_paranoia_check(tty, inode, __func__))
1766 check_tty_count(tty, __func__);
1768 __tty_fasync(-1, filp, 0);
1771 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1772 tty->driver->subtype == PTY_TYPE_MASTER);
1773 /* Review: parallel close */
1776 if (tty_release_checks(tty, o_tty, idx)) {
1781 #ifdef TTY_DEBUG_HANGUP
1782 printk(KERN_DEBUG "%s: %s (tty count=%d)...\n", __func__,
1783 tty_name(tty, buf), tty->count);
1786 if (tty->ops->close)
1787 tty->ops->close(tty, filp);
1791 * Sanity check: if tty->count is going to zero, there shouldn't be
1792 * any waiters on tty->read_wait or tty->write_wait. We test the
1793 * wait queues and kick everyone out _before_ actually starting to
1794 * close. This ensures that we won't block while releasing the tty
1797 * The test for the o_tty closing is necessary, since the master and
1798 * slave sides may close in any order. If the slave side closes out
1799 * first, its count will be one, since the master side holds an open.
1800 * Thus this test wouldn't be triggered at the time the slave closes,
1803 tty_lock_pair(tty, o_tty);
1806 tty_closing = tty->count <= 1;
1807 o_tty_closing = o_tty &&
1808 (o_tty->count <= (pty_master ? 1 : 0));
1812 if (waitqueue_active(&tty->read_wait)) {
1813 wake_up_poll(&tty->read_wait, POLLIN);
1816 if (waitqueue_active(&tty->write_wait)) {
1817 wake_up_poll(&tty->write_wait, POLLOUT);
1821 if (o_tty_closing) {
1822 if (waitqueue_active(&o_tty->read_wait)) {
1823 wake_up_poll(&o_tty->read_wait, POLLIN);
1826 if (waitqueue_active(&o_tty->write_wait)) {
1827 wake_up_poll(&o_tty->write_wait, POLLOUT);
1834 printk(KERN_WARNING "%s: %s: read/write wait queue active!\n",
1835 __func__, tty_name(tty, buf));
1840 * The closing flags are now consistent with the open counts on
1841 * both sides, and we've completed the last operation that could
1842 * block, so it's safe to proceed with closing.
1844 * We must *not* drop the tty_mutex until we ensure that a further
1845 * entry into tty_open can not pick up this tty.
1848 if (--o_tty->count < 0) {
1849 printk(KERN_WARNING "%s: bad pty slave count (%d) for %s\n",
1850 __func__, o_tty->count, tty_name(o_tty, buf));
1854 if (--tty->count < 0) {
1855 printk(KERN_WARNING "%s: bad tty->count (%d) for %s\n",
1856 __func__, tty->count, tty_name(tty, buf));
1861 * We've decremented tty->count, so we need to remove this file
1862 * descriptor off the tty->tty_files list; this serves two
1864 * - check_tty_count sees the correct number of file descriptors
1865 * associated with this tty.
1866 * - do_tty_hangup no longer sees this file descriptor as
1867 * something that needs to be handled for hangups.
1872 * Perform some housekeeping before deciding whether to return.
1874 * If _either_ side is closing, make sure there aren't any
1875 * processes that still think tty or o_tty is their controlling
1878 if (tty_closing || o_tty_closing) {
1879 read_lock(&tasklist_lock);
1880 session_clear_tty(tty->session);
1882 session_clear_tty(o_tty->session);
1883 read_unlock(&tasklist_lock);
1886 tty_unlock_pair(tty, o_tty);
1887 /* At this point, the tty->count == 0 should ensure a dead tty
1888 cannot be re-opened by a racing opener */
1890 /* check whether both sides are closing ... */
1891 if (!tty_closing || (o_tty && !o_tty_closing))
1894 #ifdef TTY_DEBUG_HANGUP
1895 printk(KERN_DEBUG "%s: %s: final close\n", __func__, tty_name(tty, buf));
1898 * Ask the line discipline code to release its structures
1900 tty_ldisc_release(tty, o_tty);
1902 /* Wait for pending work before tty destruction commmences */
1903 tty_flush_works(tty);
1905 tty_flush_works(o_tty);
1907 #ifdef TTY_DEBUG_HANGUP
1908 printk(KERN_DEBUG "%s: %s: freeing structure...\n", __func__, tty_name(tty, buf));
1911 * The release_tty function takes care of the details of clearing
1912 * the slots and preserving the termios structure. The tty_unlock_pair
1913 * should be safe as we keep a kref while the tty is locked (so the
1914 * unlock never unlocks a freed tty).
1916 mutex_lock(&tty_mutex);
1917 release_tty(tty, idx);
1918 mutex_unlock(&tty_mutex);
1924 * tty_open_current_tty - get locked tty of current task
1925 * @device: device number
1926 * @filp: file pointer to tty
1927 * @return: locked tty of the current task iff @device is /dev/tty
1929 * Performs a re-open of the current task's controlling tty.
1931 * We cannot return driver and index like for the other nodes because
1932 * devpts will not work then. It expects inodes to be from devpts FS.
1934 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1936 struct tty_struct *tty;
1939 if (device != MKDEV(TTYAUX_MAJOR, 0))
1942 tty = get_current_tty();
1944 return ERR_PTR(-ENXIO);
1946 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1949 tty_kref_put(tty); /* safe to drop the kref now */
1951 retval = tty_reopen(tty);
1954 tty = ERR_PTR(retval);
1960 * tty_lookup_driver - lookup a tty driver for a given device file
1961 * @device: device number
1962 * @filp: file pointer to tty
1963 * @noctty: set if the device should not become a controlling tty
1964 * @index: index for the device in the @return driver
1965 * @return: driver for this inode (with increased refcount)
1967 * If @return is not erroneous, the caller is responsible to decrement the
1968 * refcount by tty_driver_kref_put.
1970 * Locking: tty_mutex protects get_tty_driver
1972 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1973 int *noctty, int *index)
1975 struct tty_driver *driver;
1979 case MKDEV(TTY_MAJOR, 0): {
1980 extern struct tty_driver *console_driver;
1981 driver = tty_driver_kref_get(console_driver);
1982 *index = fg_console;
1987 case MKDEV(TTYAUX_MAJOR, 1): {
1988 struct tty_driver *console_driver = console_device(index);
1989 if (console_driver) {
1990 driver = tty_driver_kref_get(console_driver);
1992 /* Don't let /dev/console block */
1993 filp->f_flags |= O_NONBLOCK;
1998 return ERR_PTR(-ENODEV);
2001 driver = get_tty_driver(device, index);
2003 return ERR_PTR(-ENODEV);
2010 * tty_open - open a tty device
2011 * @inode: inode of device file
2012 * @filp: file pointer to tty
2014 * tty_open and tty_release keep up the tty count that contains the
2015 * number of opens done on a tty. We cannot use the inode-count, as
2016 * different inodes might point to the same tty.
2018 * Open-counting is needed for pty masters, as well as for keeping
2019 * track of serial lines: DTR is dropped when the last close happens.
2020 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2022 * The termios state of a pty is reset on first open so that
2023 * settings don't persist across reuse.
2025 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
2026 * tty->count should protect the rest.
2027 * ->siglock protects ->signal/->sighand
2029 * Note: the tty_unlock/lock cases without a ref are only safe due to
2033 static int tty_open(struct inode *inode, struct file *filp)
2035 struct tty_struct *tty;
2037 struct tty_driver *driver = NULL;
2039 dev_t device = inode->i_rdev;
2040 unsigned saved_flags = filp->f_flags;
2042 nonseekable_open(inode, filp);
2045 retval = tty_alloc_file(filp);
2049 noctty = filp->f_flags & O_NOCTTY;
2053 tty = tty_open_current_tty(device, filp);
2055 mutex_lock(&tty_mutex);
2056 driver = tty_lookup_driver(device, filp, &noctty, &index);
2057 if (IS_ERR(driver)) {
2058 retval = PTR_ERR(driver);
2062 /* check whether we're reopening an existing tty */
2063 tty = tty_driver_lookup_tty(driver, inode, index);
2065 retval = PTR_ERR(tty);
2070 mutex_unlock(&tty_mutex);
2072 /* safe to drop the kref from tty_driver_lookup_tty() */
2074 retval = tty_reopen(tty);
2077 tty = ERR_PTR(retval);
2079 } else { /* Returns with the tty_lock held for now */
2080 tty = tty_init_dev(driver, index);
2081 mutex_unlock(&tty_mutex);
2084 tty_driver_kref_put(driver);
2088 retval = PTR_ERR(tty);
2092 tty_add_file(tty, filp);
2094 check_tty_count(tty, __func__);
2095 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2096 tty->driver->subtype == PTY_TYPE_MASTER)
2098 #ifdef TTY_DEBUG_HANGUP
2099 printk(KERN_DEBUG "%s: opening %s...\n", __func__, tty->name);
2102 retval = tty->ops->open(tty, filp);
2105 filp->f_flags = saved_flags;
2107 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
2108 !capable(CAP_SYS_ADMIN))
2112 #ifdef TTY_DEBUG_HANGUP
2113 printk(KERN_DEBUG "%s: error %d in opening %s...\n", __func__,
2116 tty_unlock(tty); /* need to call tty_release without BTM */
2117 tty_release(inode, filp);
2118 if (retval != -ERESTARTSYS)
2121 if (signal_pending(current))
2126 * Need to reset f_op in case a hangup happened.
2128 if (filp->f_op == &hung_up_tty_fops)
2129 filp->f_op = &tty_fops;
2132 clear_bit(TTY_HUPPED, &tty->flags);
2135 read_lock(&tasklist_lock);
2136 spin_lock_irq(¤t->sighand->siglock);
2138 current->signal->leader &&
2139 !current->signal->tty &&
2140 tty->session == NULL)
2141 __proc_set_tty(tty);
2142 spin_unlock_irq(¤t->sighand->siglock);
2143 read_unlock(&tasklist_lock);
2147 mutex_unlock(&tty_mutex);
2148 /* after locks to avoid deadlock */
2149 if (!IS_ERR_OR_NULL(driver))
2150 tty_driver_kref_put(driver);
2152 tty_free_file(filp);
2159 * tty_poll - check tty status
2160 * @filp: file being polled
2161 * @wait: poll wait structures to update
2163 * Call the line discipline polling method to obtain the poll
2164 * status of the device.
2166 * Locking: locks called line discipline but ldisc poll method
2167 * may be re-entered freely by other callers.
2170 static unsigned int tty_poll(struct file *filp, poll_table *wait)
2172 struct tty_struct *tty = file_tty(filp);
2173 struct tty_ldisc *ld;
2176 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2179 ld = tty_ldisc_ref_wait(tty);
2181 ret = (ld->ops->poll)(tty, filp, wait);
2182 tty_ldisc_deref(ld);
2186 static int __tty_fasync(int fd, struct file *filp, int on)
2188 struct tty_struct *tty = file_tty(filp);
2189 struct tty_ldisc *ldisc;
2190 unsigned long flags;
2193 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2196 retval = fasync_helper(fd, filp, on, &tty->fasync);
2200 ldisc = tty_ldisc_ref(tty);
2202 if (ldisc->ops->fasync)
2203 ldisc->ops->fasync(tty, on);
2204 tty_ldisc_deref(ldisc);
2211 spin_lock_irqsave(&tty->ctrl_lock, flags);
2214 type = PIDTYPE_PGID;
2216 pid = task_pid(current);
2220 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2221 __f_setown(filp, pid, type, 0);
2229 static int tty_fasync(int fd, struct file *filp, int on)
2231 struct tty_struct *tty = file_tty(filp);
2235 retval = __tty_fasync(fd, filp, on);
2242 * tiocsti - fake input character
2243 * @tty: tty to fake input into
2244 * @p: pointer to character
2246 * Fake input to a tty device. Does the necessary locking and
2249 * FIXME: does not honour flow control ??
2252 * Called functions take tty_ldiscs_lock
2253 * current->signal->tty check is safe without locks
2255 * FIXME: may race normal receive processing
2258 static int tiocsti(struct tty_struct *tty, char __user *p)
2261 struct tty_ldisc *ld;
2263 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2265 if (get_user(ch, p))
2267 tty_audit_tiocsti(tty, ch);
2268 ld = tty_ldisc_ref_wait(tty);
2269 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2270 tty_ldisc_deref(ld);
2275 * tiocgwinsz - implement window query ioctl
2277 * @arg: user buffer for result
2279 * Copies the kernel idea of the window size into the user buffer.
2281 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2285 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2289 mutex_lock(&tty->winsize_mutex);
2290 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2291 mutex_unlock(&tty->winsize_mutex);
2293 return err ? -EFAULT: 0;
2297 * tty_do_resize - resize event
2298 * @tty: tty being resized
2299 * @rows: rows (character)
2300 * @cols: cols (character)
2302 * Update the termios variables and send the necessary signals to
2303 * peform a terminal resize correctly
2306 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2311 mutex_lock(&tty->winsize_mutex);
2312 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2315 /* Signal the foreground process group */
2316 pgrp = tty_get_pgrp(tty);
2318 kill_pgrp(pgrp, SIGWINCH, 1);
2323 mutex_unlock(&tty->winsize_mutex);
2326 EXPORT_SYMBOL(tty_do_resize);
2329 * tiocswinsz - implement window size set ioctl
2330 * @tty; tty side of tty
2331 * @arg: user buffer for result
2333 * Copies the user idea of the window size to the kernel. Traditionally
2334 * this is just advisory information but for the Linux console it
2335 * actually has driver level meaning and triggers a VC resize.
2338 * Driver dependent. The default do_resize method takes the
2339 * tty termios mutex and ctrl_lock. The console takes its own lock
2340 * then calls into the default method.
2343 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2345 struct winsize tmp_ws;
2346 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2349 if (tty->ops->resize)
2350 return tty->ops->resize(tty, &tmp_ws);
2352 return tty_do_resize(tty, &tmp_ws);
2356 * tioccons - allow admin to move logical console
2357 * @file: the file to become console
2359 * Allow the administrator to move the redirected console device
2361 * Locking: uses redirect_lock to guard the redirect information
2364 static int tioccons(struct file *file)
2366 if (!capable(CAP_SYS_ADMIN))
2368 if (file->f_op->write == redirected_tty_write) {
2370 spin_lock(&redirect_lock);
2373 spin_unlock(&redirect_lock);
2378 spin_lock(&redirect_lock);
2380 spin_unlock(&redirect_lock);
2383 redirect = get_file(file);
2384 spin_unlock(&redirect_lock);
2389 * fionbio - non blocking ioctl
2390 * @file: file to set blocking value
2391 * @p: user parameter
2393 * Historical tty interfaces had a blocking control ioctl before
2394 * the generic functionality existed. This piece of history is preserved
2395 * in the expected tty API of posix OS's.
2397 * Locking: none, the open file handle ensures it won't go away.
2400 static int fionbio(struct file *file, int __user *p)
2404 if (get_user(nonblock, p))
2407 spin_lock(&file->f_lock);
2409 file->f_flags |= O_NONBLOCK;
2411 file->f_flags &= ~O_NONBLOCK;
2412 spin_unlock(&file->f_lock);
2417 * tiocsctty - set controlling tty
2418 * @tty: tty structure
2419 * @arg: user argument
2421 * This ioctl is used to manage job control. It permits a session
2422 * leader to set this tty as the controlling tty for the session.
2425 * Takes tty_lock() to serialize proc_set_tty() for this tty
2426 * Takes tasklist_lock internally to walk sessions
2427 * Takes ->siglock() when updating signal->tty
2430 static int tiocsctty(struct tty_struct *tty, int arg)
2435 read_lock(&tasklist_lock);
2437 if (current->signal->leader && (task_session(current) == tty->session))
2441 * The process must be a session leader and
2442 * not have a controlling tty already.
2444 if (!current->signal->leader || current->signal->tty) {
2451 * This tty is already the controlling
2452 * tty for another session group!
2454 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2458 session_clear_tty(tty->session);
2466 read_unlock(&tasklist_lock);
2472 * tty_get_pgrp - return a ref counted pgrp pid
2475 * Returns a refcounted instance of the pid struct for the process
2476 * group controlling the tty.
2479 struct pid *tty_get_pgrp(struct tty_struct *tty)
2481 unsigned long flags;
2484 spin_lock_irqsave(&tty->ctrl_lock, flags);
2485 pgrp = get_pid(tty->pgrp);
2486 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2490 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2493 * This checks not only the pgrp, but falls back on the pid if no
2494 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
2497 * The caller must hold rcu lock or the tasklist lock.
2499 static struct pid *session_of_pgrp(struct pid *pgrp)
2501 struct task_struct *p;
2502 struct pid *sid = NULL;
2504 p = pid_task(pgrp, PIDTYPE_PGID);
2506 p = pid_task(pgrp, PIDTYPE_PID);
2508 sid = task_session(p);
2514 * tiocgpgrp - get process group
2515 * @tty: tty passed by user
2516 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2519 * Obtain the process group of the tty. If there is no process group
2522 * Locking: none. Reference to current->signal->tty is safe.
2525 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2530 * (tty == real_tty) is a cheap way of
2531 * testing if the tty is NOT a master pty.
2533 if (tty == real_tty && current->signal->tty != real_tty)
2535 pid = tty_get_pgrp(real_tty);
2536 ret = put_user(pid_vnr(pid), p);
2542 * tiocspgrp - attempt to set process group
2543 * @tty: tty passed by user
2544 * @real_tty: tty side device matching tty passed by user
2547 * Set the process group of the tty to the session passed. Only
2548 * permitted where the tty session is our session.
2550 * Locking: RCU, ctrl lock
2553 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2557 int retval = tty_check_change(real_tty);
2558 unsigned long flags;
2564 if (!current->signal->tty ||
2565 (current->signal->tty != real_tty) ||
2566 (real_tty->session != task_session(current)))
2568 if (get_user(pgrp_nr, p))
2573 pgrp = find_vpid(pgrp_nr);
2578 if (session_of_pgrp(pgrp) != task_session(current))
2581 spin_lock_irqsave(&tty->ctrl_lock, flags);
2582 put_pid(real_tty->pgrp);
2583 real_tty->pgrp = get_pid(pgrp);
2584 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2591 * tiocgsid - get session id
2592 * @tty: tty passed by user
2593 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2594 * @p: pointer to returned session id
2596 * Obtain the session id of the tty. If there is no session
2599 * Locking: none. Reference to current->signal->tty is safe.
2602 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2605 * (tty == real_tty) is a cheap way of
2606 * testing if the tty is NOT a master pty.
2608 if (tty == real_tty && current->signal->tty != real_tty)
2610 if (!real_tty->session)
2612 return put_user(pid_vnr(real_tty->session), p);
2616 * tiocsetd - set line discipline
2618 * @p: pointer to user data
2620 * Set the line discipline according to user request.
2622 * Locking: see tty_set_ldisc, this function is just a helper
2625 static int tiocsetd(struct tty_struct *tty, int __user *p)
2630 if (get_user(ldisc, p))
2633 ret = tty_set_ldisc(tty, ldisc);
2639 * send_break - performed time break
2640 * @tty: device to break on
2641 * @duration: timeout in mS
2643 * Perform a timed break on hardware that lacks its own driver level
2644 * timed break functionality.
2647 * atomic_write_lock serializes
2651 static int send_break(struct tty_struct *tty, unsigned int duration)
2655 if (tty->ops->break_ctl == NULL)
2658 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2659 retval = tty->ops->break_ctl(tty, duration);
2661 /* Do the work ourselves */
2662 if (tty_write_lock(tty, 0) < 0)
2664 retval = tty->ops->break_ctl(tty, -1);
2667 if (!signal_pending(current))
2668 msleep_interruptible(duration);
2669 retval = tty->ops->break_ctl(tty, 0);
2671 tty_write_unlock(tty);
2672 if (signal_pending(current))
2679 * tty_tiocmget - get modem status
2681 * @file: user file pointer
2682 * @p: pointer to result
2684 * Obtain the modem status bits from the tty driver if the feature
2685 * is supported. Return -EINVAL if it is not available.
2687 * Locking: none (up to the driver)
2690 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2692 int retval = -EINVAL;
2694 if (tty->ops->tiocmget) {
2695 retval = tty->ops->tiocmget(tty);
2698 retval = put_user(retval, p);
2704 * tty_tiocmset - set modem status
2706 * @cmd: command - clear bits, set bits or set all
2707 * @p: pointer to desired bits
2709 * Set the modem status bits from the tty driver if the feature
2710 * is supported. Return -EINVAL if it is not available.
2712 * Locking: none (up to the driver)
2715 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2719 unsigned int set, clear, val;
2721 if (tty->ops->tiocmset == NULL)
2724 retval = get_user(val, p);
2740 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2741 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2742 return tty->ops->tiocmset(tty, set, clear);
2745 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2747 int retval = -EINVAL;
2748 struct serial_icounter_struct icount;
2749 memset(&icount, 0, sizeof(icount));
2750 if (tty->ops->get_icount)
2751 retval = tty->ops->get_icount(tty, &icount);
2754 if (copy_to_user(arg, &icount, sizeof(icount)))
2760 * if pty, return the slave side (real_tty)
2761 * otherwise, return self
2763 static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2765 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2766 tty->driver->subtype == PTY_TYPE_MASTER)
2772 * Split this up, as gcc can choke on it otherwise..
2774 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2776 struct tty_struct *tty = file_tty(file);
2777 struct tty_struct *real_tty;
2778 void __user *p = (void __user *)arg;
2780 struct tty_ldisc *ld;
2782 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2785 real_tty = tty_pair_get_tty(tty);
2788 * Factor out some common prep work
2796 retval = tty_check_change(tty);
2799 if (cmd != TIOCCBRK) {
2800 tty_wait_until_sent(tty, 0);
2801 if (signal_pending(current))
2812 return tiocsti(tty, p);
2814 return tiocgwinsz(real_tty, p);
2816 return tiocswinsz(real_tty, p);
2818 return real_tty != tty ? -EINVAL : tioccons(file);
2820 return fionbio(file, p);
2822 set_bit(TTY_EXCLUSIVE, &tty->flags);
2825 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2829 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2830 return put_user(excl, (int __user *)p);
2833 if (current->signal->tty != tty)
2838 return tiocsctty(tty, arg);
2840 return tiocgpgrp(tty, real_tty, p);
2842 return tiocspgrp(tty, real_tty, p);
2844 return tiocgsid(tty, real_tty, p);
2846 return put_user(tty->ldisc->ops->num, (int __user *)p);
2848 return tiocsetd(tty, p);
2850 if (!capable(CAP_SYS_ADMIN))
2856 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2857 return put_user(ret, (unsigned int __user *)p);
2862 case TIOCSBRK: /* Turn break on, unconditionally */
2863 if (tty->ops->break_ctl)
2864 return tty->ops->break_ctl(tty, -1);
2866 case TIOCCBRK: /* Turn break off, unconditionally */
2867 if (tty->ops->break_ctl)
2868 return tty->ops->break_ctl(tty, 0);
2870 case TCSBRK: /* SVID version: non-zero arg --> no break */
2871 /* non-zero arg means wait for all output data
2872 * to be sent (performed above) but don't send break.
2873 * This is used by the tcdrain() termios function.
2876 return send_break(tty, 250);
2878 case TCSBRKP: /* support for POSIX tcsendbreak() */
2879 return send_break(tty, arg ? arg*100 : 250);
2882 return tty_tiocmget(tty, p);
2886 return tty_tiocmset(tty, cmd, p);
2888 retval = tty_tiocgicount(tty, p);
2889 /* For the moment allow fall through to the old method */
2890 if (retval != -EINVAL)
2897 /* flush tty buffer and allow ldisc to process ioctl */
2898 tty_buffer_flush(tty);
2903 if (tty->ops->ioctl) {
2904 retval = (tty->ops->ioctl)(tty, cmd, arg);
2905 if (retval != -ENOIOCTLCMD)
2908 ld = tty_ldisc_ref_wait(tty);
2910 if (ld->ops->ioctl) {
2911 retval = ld->ops->ioctl(tty, file, cmd, arg);
2912 if (retval == -ENOIOCTLCMD)
2915 tty_ldisc_deref(ld);
2919 #ifdef CONFIG_COMPAT
2920 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2923 struct tty_struct *tty = file_tty(file);
2924 struct tty_ldisc *ld;
2925 int retval = -ENOIOCTLCMD;
2927 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2930 if (tty->ops->compat_ioctl) {
2931 retval = (tty->ops->compat_ioctl)(tty, cmd, arg);
2932 if (retval != -ENOIOCTLCMD)
2936 ld = tty_ldisc_ref_wait(tty);
2937 if (ld->ops->compat_ioctl)
2938 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2940 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
2941 tty_ldisc_deref(ld);
2947 static int this_tty(const void *t, struct file *file, unsigned fd)
2949 if (likely(file->f_op->read != tty_read))
2951 return file_tty(file) != t ? 0 : fd + 1;
2955 * This implements the "Secure Attention Key" --- the idea is to
2956 * prevent trojan horses by killing all processes associated with this
2957 * tty when the user hits the "Secure Attention Key". Required for
2958 * super-paranoid applications --- see the Orange Book for more details.
2960 * This code could be nicer; ideally it should send a HUP, wait a few
2961 * seconds, then send a INT, and then a KILL signal. But you then
2962 * have to coordinate with the init process, since all processes associated
2963 * with the current tty must be dead before the new getty is allowed
2966 * Now, if it would be correct ;-/ The current code has a nasty hole -
2967 * it doesn't catch files in flight. We may send the descriptor to ourselves
2968 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2970 * Nasty bug: do_SAK is being called in interrupt context. This can
2971 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2973 void __do_SAK(struct tty_struct *tty)
2978 struct task_struct *g, *p;
2979 struct pid *session;
2984 session = tty->session;
2986 tty_ldisc_flush(tty);
2988 tty_driver_flush_buffer(tty);
2990 read_lock(&tasklist_lock);
2991 /* Kill the entire session */
2992 do_each_pid_task(session, PIDTYPE_SID, p) {
2993 printk(KERN_NOTICE "SAK: killed process %d"
2994 " (%s): task_session(p)==tty->session\n",
2995 task_pid_nr(p), p->comm);
2996 send_sig(SIGKILL, p, 1);
2997 } while_each_pid_task(session, PIDTYPE_SID, p);
2998 /* Now kill any processes that happen to have the
3001 do_each_thread(g, p) {
3002 if (p->signal->tty == tty) {
3003 printk(KERN_NOTICE "SAK: killed process %d"
3004 " (%s): task_session(p)==tty->session\n",
3005 task_pid_nr(p), p->comm);
3006 send_sig(SIGKILL, p, 1);
3010 i = iterate_fd(p->files, 0, this_tty, tty);
3012 printk(KERN_NOTICE "SAK: killed process %d"
3013 " (%s): fd#%d opened to the tty\n",
3014 task_pid_nr(p), p->comm, i - 1);
3015 force_sig(SIGKILL, p);
3018 } while_each_thread(g, p);
3019 read_unlock(&tasklist_lock);
3023 static void do_SAK_work(struct work_struct *work)
3025 struct tty_struct *tty =
3026 container_of(work, struct tty_struct, SAK_work);
3031 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3032 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3033 * the values which we write to it will be identical to the values which it
3034 * already has. --akpm
3036 void do_SAK(struct tty_struct *tty)
3040 schedule_work(&tty->SAK_work);
3043 EXPORT_SYMBOL(do_SAK);
3045 static int dev_match_devt(struct device *dev, const void *data)
3047 const dev_t *devt = data;
3048 return dev->devt == *devt;
3051 /* Must put_device() after it's unused! */
3052 static struct device *tty_get_device(struct tty_struct *tty)
3054 dev_t devt = tty_devnum(tty);
3055 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
3062 * This subroutine allocates and initializes a tty structure.
3064 * Locking: none - tty in question is not exposed at this point
3067 struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
3069 struct tty_struct *tty;
3071 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
3075 kref_init(&tty->kref);
3076 tty->magic = TTY_MAGIC;
3077 tty_ldisc_init(tty);
3078 tty->session = NULL;
3080 mutex_init(&tty->legacy_mutex);
3081 mutex_init(&tty->throttle_mutex);
3082 init_rwsem(&tty->termios_rwsem);
3083 mutex_init(&tty->winsize_mutex);
3084 init_ldsem(&tty->ldisc_sem);
3085 init_waitqueue_head(&tty->write_wait);
3086 init_waitqueue_head(&tty->read_wait);
3087 INIT_WORK(&tty->hangup_work, do_tty_hangup);
3088 mutex_init(&tty->atomic_write_lock);
3089 spin_lock_init(&tty->ctrl_lock);
3090 spin_lock_init(&tty->flow_lock);
3091 INIT_LIST_HEAD(&tty->tty_files);
3092 INIT_WORK(&tty->SAK_work, do_SAK_work);
3094 tty->driver = driver;
3095 tty->ops = driver->ops;
3097 tty_line_name(driver, idx, tty->name);
3098 tty->dev = tty_get_device(tty);
3104 * deinitialize_tty_struct
3105 * @tty: tty to deinitialize
3107 * This subroutine deinitializes a tty structure that has been newly
3108 * allocated but tty_release cannot be called on that yet.
3110 * Locking: none - tty in question must not be exposed at this point
3112 void deinitialize_tty_struct(struct tty_struct *tty)
3114 tty_ldisc_deinit(tty);
3118 * tty_put_char - write one character to a tty
3122 * Write one byte to the tty using the provided put_char method
3123 * if present. Returns the number of characters successfully output.
3125 * Note: the specific put_char operation in the driver layer may go
3126 * away soon. Don't call it directly, use this method
3129 int tty_put_char(struct tty_struct *tty, unsigned char ch)
3131 if (tty->ops->put_char)
3132 return tty->ops->put_char(tty, ch);
3133 return tty->ops->write(tty, &ch, 1);
3135 EXPORT_SYMBOL_GPL(tty_put_char);
3137 struct class *tty_class;
3139 static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3140 unsigned int index, unsigned int count)
3142 /* init here, since reused cdevs cause crashes */
3143 cdev_init(&driver->cdevs[index], &tty_fops);
3144 driver->cdevs[index].owner = driver->owner;
3145 return cdev_add(&driver->cdevs[index], dev, count);
3149 * tty_register_device - register a tty device
3150 * @driver: the tty driver that describes the tty device
3151 * @index: the index in the tty driver for this tty device
3152 * @device: a struct device that is associated with this tty device.
3153 * This field is optional, if there is no known struct device
3154 * for this tty device it can be set to NULL safely.
3156 * Returns a pointer to the struct device for this tty device
3157 * (or ERR_PTR(-EFOO) on error).
3159 * This call is required to be made to register an individual tty device
3160 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3161 * that bit is not set, this function should not be called by a tty
3167 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3168 struct device *device)
3170 return tty_register_device_attr(driver, index, device, NULL, NULL);
3172 EXPORT_SYMBOL(tty_register_device);
3174 static void tty_device_create_release(struct device *dev)
3176 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3181 * tty_register_device_attr - register a tty device
3182 * @driver: the tty driver that describes the tty device
3183 * @index: the index in the tty driver for this tty device
3184 * @device: a struct device that is associated with this tty device.
3185 * This field is optional, if there is no known struct device
3186 * for this tty device it can be set to NULL safely.
3187 * @drvdata: Driver data to be set to device.
3188 * @attr_grp: Attribute group to be set on device.
3190 * Returns a pointer to the struct device for this tty device
3191 * (or ERR_PTR(-EFOO) on error).
3193 * This call is required to be made to register an individual tty device
3194 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3195 * that bit is not set, this function should not be called by a tty
3200 struct device *tty_register_device_attr(struct tty_driver *driver,
3201 unsigned index, struct device *device,
3203 const struct attribute_group **attr_grp)
3206 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3207 struct device *dev = NULL;
3208 int retval = -ENODEV;
3211 if (index >= driver->num) {
3212 printk(KERN_ERR "Attempt to register invalid tty line number "
3214 return ERR_PTR(-EINVAL);
3217 if (driver->type == TTY_DRIVER_TYPE_PTY)
3218 pty_line_name(driver, index, name);
3220 tty_line_name(driver, index, name);
3222 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3223 retval = tty_cdev_add(driver, devt, index, 1);
3229 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3236 dev->class = tty_class;
3237 dev->parent = device;
3238 dev->release = tty_device_create_release;
3239 dev_set_name(dev, "%s", name);
3240 dev->groups = attr_grp;
3241 dev_set_drvdata(dev, drvdata);
3243 retval = device_register(dev);
3252 cdev_del(&driver->cdevs[index]);
3253 return ERR_PTR(retval);
3255 EXPORT_SYMBOL_GPL(tty_register_device_attr);
3258 * tty_unregister_device - unregister a tty device
3259 * @driver: the tty driver that describes the tty device
3260 * @index: the index in the tty driver for this tty device
3262 * If a tty device is registered with a call to tty_register_device() then
3263 * this function must be called when the tty device is gone.
3268 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3270 device_destroy(tty_class,
3271 MKDEV(driver->major, driver->minor_start) + index);
3272 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC))
3273 cdev_del(&driver->cdevs[index]);
3275 EXPORT_SYMBOL(tty_unregister_device);
3278 * __tty_alloc_driver -- allocate tty driver
3279 * @lines: count of lines this driver can handle at most
3280 * @owner: module which is repsonsible for this driver
3281 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3283 * This should not be called directly, some of the provided macros should be
3284 * used instead. Use IS_ERR and friends on @retval.
3286 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3287 unsigned long flags)
3289 struct tty_driver *driver;
3290 unsigned int cdevs = 1;
3293 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3294 return ERR_PTR(-EINVAL);
3296 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3298 return ERR_PTR(-ENOMEM);
3300 kref_init(&driver->kref);
3301 driver->magic = TTY_DRIVER_MAGIC;
3302 driver->num = lines;
3303 driver->owner = owner;
3304 driver->flags = flags;
3306 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3307 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3309 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3311 if (!driver->ttys || !driver->termios) {
3317 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3318 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3320 if (!driver->ports) {
3327 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3328 if (!driver->cdevs) {
3335 kfree(driver->ports);
3336 kfree(driver->ttys);
3337 kfree(driver->termios);
3339 return ERR_PTR(err);
3341 EXPORT_SYMBOL(__tty_alloc_driver);
3343 static void destruct_tty_driver(struct kref *kref)
3345 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3347 struct ktermios *tp;
3349 if (driver->flags & TTY_DRIVER_INSTALLED) {
3351 * Free the termios and termios_locked structures because
3352 * we don't want to get memory leaks when modular tty
3353 * drivers are removed from the kernel.
3355 for (i = 0; i < driver->num; i++) {
3356 tp = driver->termios[i];
3358 driver->termios[i] = NULL;
3361 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3362 tty_unregister_device(driver, i);
3364 proc_tty_unregister_driver(driver);
3365 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3366 cdev_del(&driver->cdevs[0]);
3368 kfree(driver->cdevs);
3369 kfree(driver->ports);
3370 kfree(driver->termios);
3371 kfree(driver->ttys);
3375 void tty_driver_kref_put(struct tty_driver *driver)
3377 kref_put(&driver->kref, destruct_tty_driver);
3379 EXPORT_SYMBOL(tty_driver_kref_put);
3381 void tty_set_operations(struct tty_driver *driver,
3382 const struct tty_operations *op)
3386 EXPORT_SYMBOL(tty_set_operations);
3388 void put_tty_driver(struct tty_driver *d)
3390 tty_driver_kref_put(d);
3392 EXPORT_SYMBOL(put_tty_driver);
3395 * Called by a tty driver to register itself.
3397 int tty_register_driver(struct tty_driver *driver)
3404 if (!driver->major) {
3405 error = alloc_chrdev_region(&dev, driver->minor_start,
3406 driver->num, driver->name);
3408 driver->major = MAJOR(dev);
3409 driver->minor_start = MINOR(dev);
3412 dev = MKDEV(driver->major, driver->minor_start);
3413 error = register_chrdev_region(dev, driver->num, driver->name);
3418 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3419 error = tty_cdev_add(driver, dev, 0, driver->num);
3421 goto err_unreg_char;
3424 mutex_lock(&tty_mutex);
3425 list_add(&driver->tty_drivers, &tty_drivers);
3426 mutex_unlock(&tty_mutex);
3428 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3429 for (i = 0; i < driver->num; i++) {
3430 d = tty_register_device(driver, i, NULL);
3433 goto err_unreg_devs;
3437 proc_tty_register_driver(driver);
3438 driver->flags |= TTY_DRIVER_INSTALLED;
3442 for (i--; i >= 0; i--)
3443 tty_unregister_device(driver, i);
3445 mutex_lock(&tty_mutex);
3446 list_del(&driver->tty_drivers);
3447 mutex_unlock(&tty_mutex);
3450 unregister_chrdev_region(dev, driver->num);
3454 EXPORT_SYMBOL(tty_register_driver);
3457 * Called by a tty driver to unregister itself.
3459 int tty_unregister_driver(struct tty_driver *driver)
3463 if (driver->refcount)
3466 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3468 mutex_lock(&tty_mutex);
3469 list_del(&driver->tty_drivers);
3470 mutex_unlock(&tty_mutex);
3474 EXPORT_SYMBOL(tty_unregister_driver);
3476 dev_t tty_devnum(struct tty_struct *tty)
3478 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3480 EXPORT_SYMBOL(tty_devnum);
3482 void tty_default_fops(struct file_operations *fops)
3488 * Initialize the console device. This is called *early*, so
3489 * we can't necessarily depend on lots of kernel help here.
3490 * Just do some early initializations, and do the complex setup
3493 void __init console_init(void)
3497 /* Setup the default TTY line discipline. */
3501 * set up the console device so that later boot sequences can
3502 * inform about problems etc..
3504 call = __con_initcall_start;
3505 while (call < __con_initcall_end) {
3511 static char *tty_devnode(struct device *dev, umode_t *mode)
3515 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3516 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3521 static int __init tty_class_init(void)
3523 tty_class = class_create(THIS_MODULE, "tty");
3524 if (IS_ERR(tty_class))
3525 return PTR_ERR(tty_class);
3526 tty_class->devnode = tty_devnode;
3530 postcore_initcall(tty_class_init);
3532 /* 3/2004 jmc: why do these devices exist? */
3533 static struct cdev tty_cdev, console_cdev;
3535 static ssize_t show_cons_active(struct device *dev,
3536 struct device_attribute *attr, char *buf)
3538 struct console *cs[16];
3544 for_each_console(c) {
3549 if ((c->flags & CON_ENABLED) == 0)
3552 if (i >= ARRAY_SIZE(cs))
3556 int index = cs[i]->index;
3557 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3559 /* don't resolve tty0 as some programs depend on it */
3560 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3561 count += tty_line_name(drv, index, buf + count);
3563 count += sprintf(buf + count, "%s%d",
3564 cs[i]->name, cs[i]->index);
3566 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3572 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3574 static struct device *consdev;
3576 void console_sysfs_notify(void)
3579 sysfs_notify(&consdev->kobj, NULL, "active");
3583 * Ok, now we can initialize the rest of the tty devices and can count
3584 * on memory allocations, interrupts etc..
3586 int __init tty_init(void)
3588 cdev_init(&tty_cdev, &tty_fops);
3589 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3590 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3591 panic("Couldn't register /dev/tty driver\n");
3592 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3594 cdev_init(&console_cdev, &console_fops);
3595 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3596 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3597 panic("Couldn't register /dev/console driver\n");
3598 consdev = device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3600 if (IS_ERR(consdev))
3603 WARN_ON(device_create_file(consdev, &dev_attr_active) < 0);
3606 vty_init(&console_fops);