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)
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/pty pair
1588 * @tty: tty device to flush works for (or either end of a pty pair)
1590 * Sync flush all works belonging to @tty (and the 'other' tty).
1592 static void tty_flush_works(struct tty_struct *tty)
1594 flush_work(&tty->SAK_work);
1595 flush_work(&tty->hangup_work);
1597 flush_work(&tty->link->SAK_work);
1598 flush_work(&tty->link->hangup_work);
1603 * release_one_tty - release tty structure memory
1604 * @kref: kref of tty we are obliterating
1606 * Releases memory associated with a tty structure, and clears out the
1607 * driver table slots. This function is called when a device is no longer
1608 * in use. It also gets called when setup of a device fails.
1611 * takes the file list lock internally when working on the list
1612 * of ttys that the driver keeps.
1614 * This method gets called from a work queue so that the driver private
1615 * cleanup ops can sleep (needed for USB at least)
1617 static void release_one_tty(struct work_struct *work)
1619 struct tty_struct *tty =
1620 container_of(work, struct tty_struct, hangup_work);
1621 struct tty_driver *driver = tty->driver;
1622 struct module *owner = driver->owner;
1624 if (tty->ops->cleanup)
1625 tty->ops->cleanup(tty);
1628 tty_driver_kref_put(driver);
1631 spin_lock(&tty_files_lock);
1632 list_del_init(&tty->tty_files);
1633 spin_unlock(&tty_files_lock);
1636 put_pid(tty->session);
1637 free_tty_struct(tty);
1640 static void queue_release_one_tty(struct kref *kref)
1642 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1644 /* The hangup queue is now free so we can reuse it rather than
1645 waste a chunk of memory for each port */
1646 INIT_WORK(&tty->hangup_work, release_one_tty);
1647 schedule_work(&tty->hangup_work);
1651 * tty_kref_put - release a tty kref
1654 * Release a reference to a tty device and if need be let the kref
1655 * layer destruct the object for us
1658 void tty_kref_put(struct tty_struct *tty)
1661 kref_put(&tty->kref, queue_release_one_tty);
1663 EXPORT_SYMBOL(tty_kref_put);
1666 * release_tty - release tty structure memory
1668 * Release both @tty and a possible linked partner (think pty pair),
1669 * and decrement the refcount of the backing module.
1673 * takes the file list lock internally when working on the list
1674 * of ttys that the driver keeps.
1677 static void release_tty(struct tty_struct *tty, int idx)
1679 /* This should always be true but check for the moment */
1680 WARN_ON(tty->index != idx);
1681 WARN_ON(!mutex_is_locked(&tty_mutex));
1682 if (tty->ops->shutdown)
1683 tty->ops->shutdown(tty);
1684 tty_free_termios(tty);
1685 tty_driver_remove_tty(tty->driver, tty);
1686 tty->port->itty = NULL;
1688 tty->link->port->itty = NULL;
1689 cancel_work_sync(&tty->port->buf.work);
1692 tty_kref_put(tty->link);
1697 * tty_release_checks - check a tty before real release
1698 * @tty: tty to check
1699 * @o_tty: link of @tty (if any)
1700 * @idx: index of the tty
1702 * Performs some paranoid checking before true release of the @tty.
1703 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1705 static int tty_release_checks(struct tty_struct *tty, int idx)
1707 #ifdef TTY_PARANOIA_CHECK
1708 if (idx < 0 || idx >= tty->driver->num) {
1709 printk(KERN_DEBUG "%s: bad idx when trying to free (%s)\n",
1710 __func__, tty->name);
1714 /* not much to check for devpts */
1715 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1718 if (tty != tty->driver->ttys[idx]) {
1719 printk(KERN_DEBUG "%s: driver.table[%d] not tty for (%s)\n",
1720 __func__, idx, tty->name);
1723 if (tty->driver->other) {
1724 struct tty_struct *o_tty = tty->link;
1726 if (o_tty != tty->driver->other->ttys[idx]) {
1727 printk(KERN_DEBUG "%s: other->table[%d] not o_tty for (%s)\n",
1728 __func__, idx, tty->name);
1731 if (o_tty->link != tty) {
1732 printk(KERN_DEBUG "%s: bad pty pointers\n", __func__);
1741 * tty_release - vfs callback for close
1742 * @inode: inode of tty
1743 * @filp: file pointer for handle to tty
1745 * Called the last time each file handle is closed that references
1746 * this tty. There may however be several such references.
1749 * Takes bkl. See tty_release_dev
1751 * Even releasing the tty structures is a tricky business.. We have
1752 * to be very careful that the structures are all released at the
1753 * same time, as interrupts might otherwise get the wrong pointers.
1755 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1756 * lead to double frees or releasing memory still in use.
1759 int tty_release(struct inode *inode, struct file *filp)
1761 struct tty_struct *tty = file_tty(filp);
1762 struct tty_struct *o_tty = NULL;
1763 int do_sleep, final;
1769 if (tty_paranoia_check(tty, inode, __func__))
1773 check_tty_count(tty, __func__);
1775 __tty_fasync(-1, filp, 0);
1778 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1779 tty->driver->subtype == PTY_TYPE_MASTER)
1782 if (tty_release_checks(tty, idx)) {
1787 #ifdef TTY_DEBUG_HANGUP
1788 printk(KERN_DEBUG "%s: %s (tty count=%d)...\n", __func__,
1789 tty_name(tty, buf), tty->count);
1792 if (tty->ops->close)
1793 tty->ops->close(tty, filp);
1795 /* If tty is pty master, lock the slave pty (stable lock order) */
1796 tty_lock_slave(o_tty);
1799 * Sanity check: if tty->count is going to zero, there shouldn't be
1800 * any waiters on tty->read_wait or tty->write_wait. We test the
1801 * wait queues and kick everyone out _before_ actually starting to
1802 * close. This ensures that we won't block while releasing the tty
1805 * The test for the o_tty closing is necessary, since the master and
1806 * slave sides may close in any order. If the slave side closes out
1807 * first, its count will be one, since the master side holds an open.
1808 * Thus this test wouldn't be triggered at the time the slave closed,
1814 if (tty->count <= 1) {
1815 if (waitqueue_active(&tty->read_wait)) {
1816 wake_up_poll(&tty->read_wait, POLLIN);
1819 if (waitqueue_active(&tty->write_wait)) {
1820 wake_up_poll(&tty->write_wait, POLLOUT);
1824 if (o_tty && o_tty->count <= 1) {
1825 if (waitqueue_active(&o_tty->read_wait)) {
1826 wake_up_poll(&o_tty->read_wait, POLLIN);
1829 if (waitqueue_active(&o_tty->write_wait)) {
1830 wake_up_poll(&o_tty->write_wait, POLLOUT);
1839 printk(KERN_WARNING "%s: %s: read/write wait queue active!\n",
1840 __func__, tty_name(tty, buf));
1842 schedule_timeout_killable(timeout);
1843 if (timeout < 120 * HZ)
1844 timeout = 2 * timeout + 1;
1846 timeout = MAX_SCHEDULE_TIMEOUT;
1850 if (--o_tty->count < 0) {
1851 printk(KERN_WARNING "%s: bad pty slave count (%d) for %s\n",
1852 __func__, o_tty->count, tty_name(o_tty, buf));
1856 if (--tty->count < 0) {
1857 printk(KERN_WARNING "%s: bad tty->count (%d) for %s\n",
1858 __func__, tty->count, tty_name(tty, buf));
1863 * We've decremented tty->count, so we need to remove this file
1864 * descriptor off the tty->tty_files list; this serves two
1866 * - check_tty_count sees the correct number of file descriptors
1867 * associated with this tty.
1868 * - do_tty_hangup no longer sees this file descriptor as
1869 * something that needs to be handled for hangups.
1874 * Perform some housekeeping before deciding whether to return.
1876 * If _either_ side is closing, make sure there aren't any
1877 * processes that still think tty or o_tty is their controlling
1881 read_lock(&tasklist_lock);
1882 session_clear_tty(tty->session);
1884 session_clear_tty(o_tty->session);
1885 read_unlock(&tasklist_lock);
1888 /* check whether both sides are closing ... */
1889 final = !tty->count && !(o_tty && o_tty->count);
1891 tty_unlock_slave(o_tty);
1894 /* At this point, the tty->count == 0 should ensure a dead tty
1895 cannot be re-opened by a racing opener */
1900 #ifdef TTY_DEBUG_HANGUP
1901 printk(KERN_DEBUG "%s: %s: final close\n", __func__, tty_name(tty, buf));
1904 * Ask the line discipline code to release its structures
1906 tty_ldisc_release(tty);
1908 /* Wait for pending work before tty destruction commmences */
1909 tty_flush_works(tty);
1911 #ifdef TTY_DEBUG_HANGUP
1912 printk(KERN_DEBUG "%s: %s: freeing structure...\n", __func__, tty_name(tty, buf));
1915 * The release_tty function takes care of the details of clearing
1916 * the slots and preserving the termios structure. The tty_unlock_pair
1917 * should be safe as we keep a kref while the tty is locked (so the
1918 * unlock never unlocks a freed tty).
1920 mutex_lock(&tty_mutex);
1921 release_tty(tty, idx);
1922 mutex_unlock(&tty_mutex);
1928 * tty_open_current_tty - get locked tty of current task
1929 * @device: device number
1930 * @filp: file pointer to tty
1931 * @return: locked tty of the current task iff @device is /dev/tty
1933 * Performs a re-open of the current task's controlling tty.
1935 * We cannot return driver and index like for the other nodes because
1936 * devpts will not work then. It expects inodes to be from devpts FS.
1938 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1940 struct tty_struct *tty;
1943 if (device != MKDEV(TTYAUX_MAJOR, 0))
1946 tty = get_current_tty();
1948 return ERR_PTR(-ENXIO);
1950 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1953 tty_kref_put(tty); /* safe to drop the kref now */
1955 retval = tty_reopen(tty);
1958 tty = ERR_PTR(retval);
1964 * tty_lookup_driver - lookup a tty driver for a given device file
1965 * @device: device number
1966 * @filp: file pointer to tty
1967 * @noctty: set if the device should not become a controlling tty
1968 * @index: index for the device in the @return driver
1969 * @return: driver for this inode (with increased refcount)
1971 * If @return is not erroneous, the caller is responsible to decrement the
1972 * refcount by tty_driver_kref_put.
1974 * Locking: tty_mutex protects get_tty_driver
1976 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1977 int *noctty, int *index)
1979 struct tty_driver *driver;
1983 case MKDEV(TTY_MAJOR, 0): {
1984 extern struct tty_driver *console_driver;
1985 driver = tty_driver_kref_get(console_driver);
1986 *index = fg_console;
1991 case MKDEV(TTYAUX_MAJOR, 1): {
1992 struct tty_driver *console_driver = console_device(index);
1993 if (console_driver) {
1994 driver = tty_driver_kref_get(console_driver);
1996 /* Don't let /dev/console block */
1997 filp->f_flags |= O_NONBLOCK;
2002 return ERR_PTR(-ENODEV);
2005 driver = get_tty_driver(device, index);
2007 return ERR_PTR(-ENODEV);
2014 * tty_open - open a tty device
2015 * @inode: inode of device file
2016 * @filp: file pointer to tty
2018 * tty_open and tty_release keep up the tty count that contains the
2019 * number of opens done on a tty. We cannot use the inode-count, as
2020 * different inodes might point to the same tty.
2022 * Open-counting is needed for pty masters, as well as for keeping
2023 * track of serial lines: DTR is dropped when the last close happens.
2024 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2026 * The termios state of a pty is reset on first open so that
2027 * settings don't persist across reuse.
2029 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
2030 * tty->count should protect the rest.
2031 * ->siglock protects ->signal/->sighand
2033 * Note: the tty_unlock/lock cases without a ref are only safe due to
2037 static int tty_open(struct inode *inode, struct file *filp)
2039 struct tty_struct *tty;
2041 struct tty_driver *driver = NULL;
2043 dev_t device = inode->i_rdev;
2044 unsigned saved_flags = filp->f_flags;
2046 nonseekable_open(inode, filp);
2049 retval = tty_alloc_file(filp);
2053 noctty = filp->f_flags & O_NOCTTY;
2057 tty = tty_open_current_tty(device, filp);
2059 mutex_lock(&tty_mutex);
2060 driver = tty_lookup_driver(device, filp, &noctty, &index);
2061 if (IS_ERR(driver)) {
2062 retval = PTR_ERR(driver);
2066 /* check whether we're reopening an existing tty */
2067 tty = tty_driver_lookup_tty(driver, inode, index);
2069 retval = PTR_ERR(tty);
2074 mutex_unlock(&tty_mutex);
2076 /* safe to drop the kref from tty_driver_lookup_tty() */
2078 retval = tty_reopen(tty);
2081 tty = ERR_PTR(retval);
2083 } else { /* Returns with the tty_lock held for now */
2084 tty = tty_init_dev(driver, index);
2085 mutex_unlock(&tty_mutex);
2088 tty_driver_kref_put(driver);
2092 retval = PTR_ERR(tty);
2096 tty_add_file(tty, filp);
2098 check_tty_count(tty, __func__);
2099 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2100 tty->driver->subtype == PTY_TYPE_MASTER)
2102 #ifdef TTY_DEBUG_HANGUP
2103 printk(KERN_DEBUG "%s: opening %s...\n", __func__, tty->name);
2106 retval = tty->ops->open(tty, filp);
2109 filp->f_flags = saved_flags;
2111 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
2112 !capable(CAP_SYS_ADMIN))
2116 #ifdef TTY_DEBUG_HANGUP
2117 printk(KERN_DEBUG "%s: error %d in opening %s...\n", __func__,
2120 tty_unlock(tty); /* need to call tty_release without BTM */
2121 tty_release(inode, filp);
2122 if (retval != -ERESTARTSYS)
2125 if (signal_pending(current))
2130 * Need to reset f_op in case a hangup happened.
2132 if (tty_hung_up_p(filp))
2133 filp->f_op = &tty_fops;
2136 clear_bit(TTY_HUPPED, &tty->flags);
2139 read_lock(&tasklist_lock);
2140 spin_lock_irq(¤t->sighand->siglock);
2142 current->signal->leader &&
2143 !current->signal->tty &&
2144 tty->session == NULL)
2145 __proc_set_tty(tty);
2146 spin_unlock_irq(¤t->sighand->siglock);
2147 read_unlock(&tasklist_lock);
2151 mutex_unlock(&tty_mutex);
2152 /* after locks to avoid deadlock */
2153 if (!IS_ERR_OR_NULL(driver))
2154 tty_driver_kref_put(driver);
2156 tty_free_file(filp);
2163 * tty_poll - check tty status
2164 * @filp: file being polled
2165 * @wait: poll wait structures to update
2167 * Call the line discipline polling method to obtain the poll
2168 * status of the device.
2170 * Locking: locks called line discipline but ldisc poll method
2171 * may be re-entered freely by other callers.
2174 static unsigned int tty_poll(struct file *filp, poll_table *wait)
2176 struct tty_struct *tty = file_tty(filp);
2177 struct tty_ldisc *ld;
2180 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2183 ld = tty_ldisc_ref_wait(tty);
2185 ret = ld->ops->poll(tty, filp, wait);
2186 tty_ldisc_deref(ld);
2190 static int __tty_fasync(int fd, struct file *filp, int on)
2192 struct tty_struct *tty = file_tty(filp);
2193 struct tty_ldisc *ldisc;
2194 unsigned long flags;
2197 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2200 retval = fasync_helper(fd, filp, on, &tty->fasync);
2204 ldisc = tty_ldisc_ref(tty);
2206 if (ldisc->ops->fasync)
2207 ldisc->ops->fasync(tty, on);
2208 tty_ldisc_deref(ldisc);
2215 spin_lock_irqsave(&tty->ctrl_lock, flags);
2218 type = PIDTYPE_PGID;
2220 pid = task_pid(current);
2224 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2225 __f_setown(filp, pid, type, 0);
2233 static int tty_fasync(int fd, struct file *filp, int on)
2235 struct tty_struct *tty = file_tty(filp);
2239 retval = __tty_fasync(fd, filp, on);
2246 * tiocsti - fake input character
2247 * @tty: tty to fake input into
2248 * @p: pointer to character
2250 * Fake input to a tty device. Does the necessary locking and
2253 * FIXME: does not honour flow control ??
2256 * Called functions take tty_ldiscs_lock
2257 * current->signal->tty check is safe without locks
2259 * FIXME: may race normal receive processing
2262 static int tiocsti(struct tty_struct *tty, char __user *p)
2265 struct tty_ldisc *ld;
2267 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2269 if (get_user(ch, p))
2271 tty_audit_tiocsti(tty, ch);
2272 ld = tty_ldisc_ref_wait(tty);
2273 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2274 tty_ldisc_deref(ld);
2279 * tiocgwinsz - implement window query ioctl
2281 * @arg: user buffer for result
2283 * Copies the kernel idea of the window size into the user buffer.
2285 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2289 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2293 mutex_lock(&tty->winsize_mutex);
2294 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2295 mutex_unlock(&tty->winsize_mutex);
2297 return err ? -EFAULT: 0;
2301 * tty_do_resize - resize event
2302 * @tty: tty being resized
2303 * @rows: rows (character)
2304 * @cols: cols (character)
2306 * Update the termios variables and send the necessary signals to
2307 * peform a terminal resize correctly
2310 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2315 mutex_lock(&tty->winsize_mutex);
2316 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2319 /* Signal the foreground process group */
2320 pgrp = tty_get_pgrp(tty);
2322 kill_pgrp(pgrp, SIGWINCH, 1);
2327 mutex_unlock(&tty->winsize_mutex);
2330 EXPORT_SYMBOL(tty_do_resize);
2333 * tiocswinsz - implement window size set ioctl
2334 * @tty; tty side of tty
2335 * @arg: user buffer for result
2337 * Copies the user idea of the window size to the kernel. Traditionally
2338 * this is just advisory information but for the Linux console it
2339 * actually has driver level meaning and triggers a VC resize.
2342 * Driver dependent. The default do_resize method takes the
2343 * tty termios mutex and ctrl_lock. The console takes its own lock
2344 * then calls into the default method.
2347 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2349 struct winsize tmp_ws;
2350 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2353 if (tty->ops->resize)
2354 return tty->ops->resize(tty, &tmp_ws);
2356 return tty_do_resize(tty, &tmp_ws);
2360 * tioccons - allow admin to move logical console
2361 * @file: the file to become console
2363 * Allow the administrator to move the redirected console device
2365 * Locking: uses redirect_lock to guard the redirect information
2368 static int tioccons(struct file *file)
2370 if (!capable(CAP_SYS_ADMIN))
2372 if (file->f_op->write == redirected_tty_write) {
2374 spin_lock(&redirect_lock);
2377 spin_unlock(&redirect_lock);
2382 spin_lock(&redirect_lock);
2384 spin_unlock(&redirect_lock);
2387 redirect = get_file(file);
2388 spin_unlock(&redirect_lock);
2393 * fionbio - non blocking ioctl
2394 * @file: file to set blocking value
2395 * @p: user parameter
2397 * Historical tty interfaces had a blocking control ioctl before
2398 * the generic functionality existed. This piece of history is preserved
2399 * in the expected tty API of posix OS's.
2401 * Locking: none, the open file handle ensures it won't go away.
2404 static int fionbio(struct file *file, int __user *p)
2408 if (get_user(nonblock, p))
2411 spin_lock(&file->f_lock);
2413 file->f_flags |= O_NONBLOCK;
2415 file->f_flags &= ~O_NONBLOCK;
2416 spin_unlock(&file->f_lock);
2421 * tiocsctty - set controlling tty
2422 * @tty: tty structure
2423 * @arg: user argument
2425 * This ioctl is used to manage job control. It permits a session
2426 * leader to set this tty as the controlling tty for the session.
2429 * Takes tty_lock() to serialize proc_set_tty() for this tty
2430 * Takes tasklist_lock internally to walk sessions
2431 * Takes ->siglock() when updating signal->tty
2434 static int tiocsctty(struct tty_struct *tty, int arg)
2439 read_lock(&tasklist_lock);
2441 if (current->signal->leader && (task_session(current) == tty->session))
2445 * The process must be a session leader and
2446 * not have a controlling tty already.
2448 if (!current->signal->leader || current->signal->tty) {
2455 * This tty is already the controlling
2456 * tty for another session group!
2458 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2462 session_clear_tty(tty->session);
2470 read_unlock(&tasklist_lock);
2476 * tty_get_pgrp - return a ref counted pgrp pid
2479 * Returns a refcounted instance of the pid struct for the process
2480 * group controlling the tty.
2483 struct pid *tty_get_pgrp(struct tty_struct *tty)
2485 unsigned long flags;
2488 spin_lock_irqsave(&tty->ctrl_lock, flags);
2489 pgrp = get_pid(tty->pgrp);
2490 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2494 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2497 * This checks not only the pgrp, but falls back on the pid if no
2498 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
2501 * The caller must hold rcu lock or the tasklist lock.
2503 static struct pid *session_of_pgrp(struct pid *pgrp)
2505 struct task_struct *p;
2506 struct pid *sid = NULL;
2508 p = pid_task(pgrp, PIDTYPE_PGID);
2510 p = pid_task(pgrp, PIDTYPE_PID);
2512 sid = task_session(p);
2518 * tiocgpgrp - get process group
2519 * @tty: tty passed by user
2520 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2523 * Obtain the process group of the tty. If there is no process group
2526 * Locking: none. Reference to current->signal->tty is safe.
2529 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2534 * (tty == real_tty) is a cheap way of
2535 * testing if the tty is NOT a master pty.
2537 if (tty == real_tty && current->signal->tty != real_tty)
2539 pid = tty_get_pgrp(real_tty);
2540 ret = put_user(pid_vnr(pid), p);
2546 * tiocspgrp - attempt to set process group
2547 * @tty: tty passed by user
2548 * @real_tty: tty side device matching tty passed by user
2551 * Set the process group of the tty to the session passed. Only
2552 * permitted where the tty session is our session.
2554 * Locking: RCU, ctrl lock
2557 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2561 int retval = tty_check_change(real_tty);
2562 unsigned long flags;
2568 if (!current->signal->tty ||
2569 (current->signal->tty != real_tty) ||
2570 (real_tty->session != task_session(current)))
2572 if (get_user(pgrp_nr, p))
2577 pgrp = find_vpid(pgrp_nr);
2582 if (session_of_pgrp(pgrp) != task_session(current))
2585 spin_lock_irqsave(&tty->ctrl_lock, flags);
2586 put_pid(real_tty->pgrp);
2587 real_tty->pgrp = get_pid(pgrp);
2588 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2595 * tiocgsid - get session id
2596 * @tty: tty passed by user
2597 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2598 * @p: pointer to returned session id
2600 * Obtain the session id of the tty. If there is no session
2603 * Locking: none. Reference to current->signal->tty is safe.
2606 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2609 * (tty == real_tty) is a cheap way of
2610 * testing if the tty is NOT a master pty.
2612 if (tty == real_tty && current->signal->tty != real_tty)
2614 if (!real_tty->session)
2616 return put_user(pid_vnr(real_tty->session), p);
2620 * tiocsetd - set line discipline
2622 * @p: pointer to user data
2624 * Set the line discipline according to user request.
2626 * Locking: see tty_set_ldisc, this function is just a helper
2629 static int tiocsetd(struct tty_struct *tty, int __user *p)
2634 if (get_user(ldisc, p))
2637 ret = tty_set_ldisc(tty, ldisc);
2643 * send_break - performed time break
2644 * @tty: device to break on
2645 * @duration: timeout in mS
2647 * Perform a timed break on hardware that lacks its own driver level
2648 * timed break functionality.
2651 * atomic_write_lock serializes
2655 static int send_break(struct tty_struct *tty, unsigned int duration)
2659 if (tty->ops->break_ctl == NULL)
2662 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2663 retval = tty->ops->break_ctl(tty, duration);
2665 /* Do the work ourselves */
2666 if (tty_write_lock(tty, 0) < 0)
2668 retval = tty->ops->break_ctl(tty, -1);
2671 if (!signal_pending(current))
2672 msleep_interruptible(duration);
2673 retval = tty->ops->break_ctl(tty, 0);
2675 tty_write_unlock(tty);
2676 if (signal_pending(current))
2683 * tty_tiocmget - get modem status
2685 * @file: user file pointer
2686 * @p: pointer to result
2688 * Obtain the modem status bits from the tty driver if the feature
2689 * is supported. Return -EINVAL if it is not available.
2691 * Locking: none (up to the driver)
2694 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2696 int retval = -EINVAL;
2698 if (tty->ops->tiocmget) {
2699 retval = tty->ops->tiocmget(tty);
2702 retval = put_user(retval, p);
2708 * tty_tiocmset - set modem status
2710 * @cmd: command - clear bits, set bits or set all
2711 * @p: pointer to desired bits
2713 * Set the modem status bits from the tty driver if the feature
2714 * is supported. Return -EINVAL if it is not available.
2716 * Locking: none (up to the driver)
2719 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2723 unsigned int set, clear, val;
2725 if (tty->ops->tiocmset == NULL)
2728 retval = get_user(val, p);
2744 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2745 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2746 return tty->ops->tiocmset(tty, set, clear);
2749 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2751 int retval = -EINVAL;
2752 struct serial_icounter_struct icount;
2753 memset(&icount, 0, sizeof(icount));
2754 if (tty->ops->get_icount)
2755 retval = tty->ops->get_icount(tty, &icount);
2758 if (copy_to_user(arg, &icount, sizeof(icount)))
2763 static void tty_warn_deprecated_flags(struct serial_struct __user *ss)
2765 static DEFINE_RATELIMIT_STATE(depr_flags,
2766 DEFAULT_RATELIMIT_INTERVAL,
2767 DEFAULT_RATELIMIT_BURST);
2768 char comm[TASK_COMM_LEN];
2771 if (get_user(flags, &ss->flags))
2774 flags &= ASYNC_DEPRECATED;
2776 if (flags && __ratelimit(&depr_flags))
2777 pr_warning("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2778 __func__, get_task_comm(comm, current), flags);
2782 * if pty, return the slave side (real_tty)
2783 * otherwise, return self
2785 static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2787 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2788 tty->driver->subtype == PTY_TYPE_MASTER)
2794 * Split this up, as gcc can choke on it otherwise..
2796 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2798 struct tty_struct *tty = file_tty(file);
2799 struct tty_struct *real_tty;
2800 void __user *p = (void __user *)arg;
2802 struct tty_ldisc *ld;
2804 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2807 real_tty = tty_pair_get_tty(tty);
2810 * Factor out some common prep work
2818 retval = tty_check_change(tty);
2821 if (cmd != TIOCCBRK) {
2822 tty_wait_until_sent(tty, 0);
2823 if (signal_pending(current))
2834 return tiocsti(tty, p);
2836 return tiocgwinsz(real_tty, p);
2838 return tiocswinsz(real_tty, p);
2840 return real_tty != tty ? -EINVAL : tioccons(file);
2842 return fionbio(file, p);
2844 set_bit(TTY_EXCLUSIVE, &tty->flags);
2847 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2851 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2852 return put_user(excl, (int __user *)p);
2855 if (current->signal->tty != tty)
2860 return tiocsctty(tty, arg);
2862 return tiocgpgrp(tty, real_tty, p);
2864 return tiocspgrp(tty, real_tty, p);
2866 return tiocgsid(tty, real_tty, p);
2868 return put_user(tty->ldisc->ops->num, (int __user *)p);
2870 return tiocsetd(tty, p);
2872 if (!capable(CAP_SYS_ADMIN))
2878 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2879 return put_user(ret, (unsigned int __user *)p);
2884 case TIOCSBRK: /* Turn break on, unconditionally */
2885 if (tty->ops->break_ctl)
2886 return tty->ops->break_ctl(tty, -1);
2888 case TIOCCBRK: /* Turn break off, unconditionally */
2889 if (tty->ops->break_ctl)
2890 return tty->ops->break_ctl(tty, 0);
2892 case TCSBRK: /* SVID version: non-zero arg --> no break */
2893 /* non-zero arg means wait for all output data
2894 * to be sent (performed above) but don't send break.
2895 * This is used by the tcdrain() termios function.
2898 return send_break(tty, 250);
2900 case TCSBRKP: /* support for POSIX tcsendbreak() */
2901 return send_break(tty, arg ? arg*100 : 250);
2904 return tty_tiocmget(tty, p);
2908 return tty_tiocmset(tty, cmd, p);
2910 retval = tty_tiocgicount(tty, p);
2911 /* For the moment allow fall through to the old method */
2912 if (retval != -EINVAL)
2919 /* flush tty buffer and allow ldisc to process ioctl */
2920 tty_buffer_flush(tty, NULL);
2925 tty_warn_deprecated_flags(p);
2928 if (tty->ops->ioctl) {
2929 retval = tty->ops->ioctl(tty, cmd, arg);
2930 if (retval != -ENOIOCTLCMD)
2933 ld = tty_ldisc_ref_wait(tty);
2935 if (ld->ops->ioctl) {
2936 retval = ld->ops->ioctl(tty, file, cmd, arg);
2937 if (retval == -ENOIOCTLCMD)
2940 tty_ldisc_deref(ld);
2944 #ifdef CONFIG_COMPAT
2945 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2948 struct tty_struct *tty = file_tty(file);
2949 struct tty_ldisc *ld;
2950 int retval = -ENOIOCTLCMD;
2952 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2955 if (tty->ops->compat_ioctl) {
2956 retval = tty->ops->compat_ioctl(tty, cmd, arg);
2957 if (retval != -ENOIOCTLCMD)
2961 ld = tty_ldisc_ref_wait(tty);
2962 if (ld->ops->compat_ioctl)
2963 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2965 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
2966 tty_ldisc_deref(ld);
2972 static int this_tty(const void *t, struct file *file, unsigned fd)
2974 if (likely(file->f_op->read != tty_read))
2976 return file_tty(file) != t ? 0 : fd + 1;
2980 * This implements the "Secure Attention Key" --- the idea is to
2981 * prevent trojan horses by killing all processes associated with this
2982 * tty when the user hits the "Secure Attention Key". Required for
2983 * super-paranoid applications --- see the Orange Book for more details.
2985 * This code could be nicer; ideally it should send a HUP, wait a few
2986 * seconds, then send a INT, and then a KILL signal. But you then
2987 * have to coordinate with the init process, since all processes associated
2988 * with the current tty must be dead before the new getty is allowed
2991 * Now, if it would be correct ;-/ The current code has a nasty hole -
2992 * it doesn't catch files in flight. We may send the descriptor to ourselves
2993 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2995 * Nasty bug: do_SAK is being called in interrupt context. This can
2996 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2998 void __do_SAK(struct tty_struct *tty)
3003 struct task_struct *g, *p;
3004 struct pid *session;
3009 session = tty->session;
3011 tty_ldisc_flush(tty);
3013 tty_driver_flush_buffer(tty);
3015 read_lock(&tasklist_lock);
3016 /* Kill the entire session */
3017 do_each_pid_task(session, PIDTYPE_SID, p) {
3018 printk(KERN_NOTICE "SAK: killed process %d"
3019 " (%s): task_session(p)==tty->session\n",
3020 task_pid_nr(p), p->comm);
3021 send_sig(SIGKILL, p, 1);
3022 } while_each_pid_task(session, PIDTYPE_SID, p);
3023 /* Now kill any processes that happen to have the
3026 do_each_thread(g, p) {
3027 if (p->signal->tty == tty) {
3028 printk(KERN_NOTICE "SAK: killed process %d"
3029 " (%s): task_session(p)==tty->session\n",
3030 task_pid_nr(p), p->comm);
3031 send_sig(SIGKILL, p, 1);
3035 i = iterate_fd(p->files, 0, this_tty, tty);
3037 printk(KERN_NOTICE "SAK: killed process %d"
3038 " (%s): fd#%d opened to the tty\n",
3039 task_pid_nr(p), p->comm, i - 1);
3040 force_sig(SIGKILL, p);
3043 } while_each_thread(g, p);
3044 read_unlock(&tasklist_lock);
3048 static void do_SAK_work(struct work_struct *work)
3050 struct tty_struct *tty =
3051 container_of(work, struct tty_struct, SAK_work);
3056 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3057 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3058 * the values which we write to it will be identical to the values which it
3059 * already has. --akpm
3061 void do_SAK(struct tty_struct *tty)
3065 schedule_work(&tty->SAK_work);
3068 EXPORT_SYMBOL(do_SAK);
3070 static int dev_match_devt(struct device *dev, const void *data)
3072 const dev_t *devt = data;
3073 return dev->devt == *devt;
3076 /* Must put_device() after it's unused! */
3077 static struct device *tty_get_device(struct tty_struct *tty)
3079 dev_t devt = tty_devnum(tty);
3080 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
3087 * This subroutine allocates and initializes a tty structure.
3089 * Locking: none - tty in question is not exposed at this point
3092 struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
3094 struct tty_struct *tty;
3096 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
3100 kref_init(&tty->kref);
3101 tty->magic = TTY_MAGIC;
3102 tty_ldisc_init(tty);
3103 tty->session = NULL;
3105 mutex_init(&tty->legacy_mutex);
3106 mutex_init(&tty->throttle_mutex);
3107 init_rwsem(&tty->termios_rwsem);
3108 mutex_init(&tty->winsize_mutex);
3109 init_ldsem(&tty->ldisc_sem);
3110 init_waitqueue_head(&tty->write_wait);
3111 init_waitqueue_head(&tty->read_wait);
3112 INIT_WORK(&tty->hangup_work, do_tty_hangup);
3113 mutex_init(&tty->atomic_write_lock);
3114 spin_lock_init(&tty->ctrl_lock);
3115 spin_lock_init(&tty->flow_lock);
3116 INIT_LIST_HEAD(&tty->tty_files);
3117 INIT_WORK(&tty->SAK_work, do_SAK_work);
3119 tty->driver = driver;
3120 tty->ops = driver->ops;
3122 tty_line_name(driver, idx, tty->name);
3123 tty->dev = tty_get_device(tty);
3129 * deinitialize_tty_struct
3130 * @tty: tty to deinitialize
3132 * This subroutine deinitializes a tty structure that has been newly
3133 * allocated but tty_release cannot be called on that yet.
3135 * Locking: none - tty in question must not be exposed at this point
3137 void deinitialize_tty_struct(struct tty_struct *tty)
3139 tty_ldisc_deinit(tty);
3143 * tty_put_char - write one character to a tty
3147 * Write one byte to the tty using the provided put_char method
3148 * if present. Returns the number of characters successfully output.
3150 * Note: the specific put_char operation in the driver layer may go
3151 * away soon. Don't call it directly, use this method
3154 int tty_put_char(struct tty_struct *tty, unsigned char ch)
3156 if (tty->ops->put_char)
3157 return tty->ops->put_char(tty, ch);
3158 return tty->ops->write(tty, &ch, 1);
3160 EXPORT_SYMBOL_GPL(tty_put_char);
3162 struct class *tty_class;
3164 static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3165 unsigned int index, unsigned int count)
3167 /* init here, since reused cdevs cause crashes */
3168 cdev_init(&driver->cdevs[index], &tty_fops);
3169 driver->cdevs[index].owner = driver->owner;
3170 return cdev_add(&driver->cdevs[index], dev, count);
3174 * tty_register_device - register a tty device
3175 * @driver: the tty driver that describes the tty device
3176 * @index: the index in the tty driver for this tty device
3177 * @device: a struct device that is associated with this tty device.
3178 * This field is optional, if there is no known struct device
3179 * for this tty device it can be set to NULL safely.
3181 * Returns a pointer to the struct device for this tty device
3182 * (or ERR_PTR(-EFOO) on error).
3184 * This call is required to be made to register an individual tty device
3185 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3186 * that bit is not set, this function should not be called by a tty
3192 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3193 struct device *device)
3195 return tty_register_device_attr(driver, index, device, NULL, NULL);
3197 EXPORT_SYMBOL(tty_register_device);
3199 static void tty_device_create_release(struct device *dev)
3201 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3206 * tty_register_device_attr - register a tty device
3207 * @driver: the tty driver that describes the tty device
3208 * @index: the index in the tty driver for this tty device
3209 * @device: a struct device that is associated with this tty device.
3210 * This field is optional, if there is no known struct device
3211 * for this tty device it can be set to NULL safely.
3212 * @drvdata: Driver data to be set to device.
3213 * @attr_grp: Attribute group to be set on device.
3215 * Returns a pointer to the struct device for this tty device
3216 * (or ERR_PTR(-EFOO) on error).
3218 * This call is required to be made to register an individual tty device
3219 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3220 * that bit is not set, this function should not be called by a tty
3225 struct device *tty_register_device_attr(struct tty_driver *driver,
3226 unsigned index, struct device *device,
3228 const struct attribute_group **attr_grp)
3231 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3232 struct device *dev = NULL;
3233 int retval = -ENODEV;
3236 if (index >= driver->num) {
3237 printk(KERN_ERR "Attempt to register invalid tty line number "
3239 return ERR_PTR(-EINVAL);
3242 if (driver->type == TTY_DRIVER_TYPE_PTY)
3243 pty_line_name(driver, index, name);
3245 tty_line_name(driver, index, name);
3247 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3248 retval = tty_cdev_add(driver, devt, index, 1);
3254 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3261 dev->class = tty_class;
3262 dev->parent = device;
3263 dev->release = tty_device_create_release;
3264 dev_set_name(dev, "%s", name);
3265 dev->groups = attr_grp;
3266 dev_set_drvdata(dev, drvdata);
3268 retval = device_register(dev);
3277 cdev_del(&driver->cdevs[index]);
3278 return ERR_PTR(retval);
3280 EXPORT_SYMBOL_GPL(tty_register_device_attr);
3283 * tty_unregister_device - unregister a tty device
3284 * @driver: the tty driver that describes the tty device
3285 * @index: the index in the tty driver for this tty device
3287 * If a tty device is registered with a call to tty_register_device() then
3288 * this function must be called when the tty device is gone.
3293 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3295 device_destroy(tty_class,
3296 MKDEV(driver->major, driver->minor_start) + index);
3297 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC))
3298 cdev_del(&driver->cdevs[index]);
3300 EXPORT_SYMBOL(tty_unregister_device);
3303 * __tty_alloc_driver -- allocate tty driver
3304 * @lines: count of lines this driver can handle at most
3305 * @owner: module which is repsonsible for this driver
3306 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3308 * This should not be called directly, some of the provided macros should be
3309 * used instead. Use IS_ERR and friends on @retval.
3311 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3312 unsigned long flags)
3314 struct tty_driver *driver;
3315 unsigned int cdevs = 1;
3318 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3319 return ERR_PTR(-EINVAL);
3321 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3323 return ERR_PTR(-ENOMEM);
3325 kref_init(&driver->kref);
3326 driver->magic = TTY_DRIVER_MAGIC;
3327 driver->num = lines;
3328 driver->owner = owner;
3329 driver->flags = flags;
3331 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3332 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3334 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3336 if (!driver->ttys || !driver->termios) {
3342 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3343 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3345 if (!driver->ports) {
3352 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3353 if (!driver->cdevs) {
3360 kfree(driver->ports);
3361 kfree(driver->ttys);
3362 kfree(driver->termios);
3364 return ERR_PTR(err);
3366 EXPORT_SYMBOL(__tty_alloc_driver);
3368 static void destruct_tty_driver(struct kref *kref)
3370 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3372 struct ktermios *tp;
3374 if (driver->flags & TTY_DRIVER_INSTALLED) {
3376 * Free the termios and termios_locked structures because
3377 * we don't want to get memory leaks when modular tty
3378 * drivers are removed from the kernel.
3380 for (i = 0; i < driver->num; i++) {
3381 tp = driver->termios[i];
3383 driver->termios[i] = NULL;
3386 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3387 tty_unregister_device(driver, i);
3389 proc_tty_unregister_driver(driver);
3390 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3391 cdev_del(&driver->cdevs[0]);
3393 kfree(driver->cdevs);
3394 kfree(driver->ports);
3395 kfree(driver->termios);
3396 kfree(driver->ttys);
3400 void tty_driver_kref_put(struct tty_driver *driver)
3402 kref_put(&driver->kref, destruct_tty_driver);
3404 EXPORT_SYMBOL(tty_driver_kref_put);
3406 void tty_set_operations(struct tty_driver *driver,
3407 const struct tty_operations *op)
3411 EXPORT_SYMBOL(tty_set_operations);
3413 void put_tty_driver(struct tty_driver *d)
3415 tty_driver_kref_put(d);
3417 EXPORT_SYMBOL(put_tty_driver);
3420 * Called by a tty driver to register itself.
3422 int tty_register_driver(struct tty_driver *driver)
3429 if (!driver->major) {
3430 error = alloc_chrdev_region(&dev, driver->minor_start,
3431 driver->num, driver->name);
3433 driver->major = MAJOR(dev);
3434 driver->minor_start = MINOR(dev);
3437 dev = MKDEV(driver->major, driver->minor_start);
3438 error = register_chrdev_region(dev, driver->num, driver->name);
3443 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3444 error = tty_cdev_add(driver, dev, 0, driver->num);
3446 goto err_unreg_char;
3449 mutex_lock(&tty_mutex);
3450 list_add(&driver->tty_drivers, &tty_drivers);
3451 mutex_unlock(&tty_mutex);
3453 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3454 for (i = 0; i < driver->num; i++) {
3455 d = tty_register_device(driver, i, NULL);
3458 goto err_unreg_devs;
3462 proc_tty_register_driver(driver);
3463 driver->flags |= TTY_DRIVER_INSTALLED;
3467 for (i--; i >= 0; i--)
3468 tty_unregister_device(driver, i);
3470 mutex_lock(&tty_mutex);
3471 list_del(&driver->tty_drivers);
3472 mutex_unlock(&tty_mutex);
3475 unregister_chrdev_region(dev, driver->num);
3479 EXPORT_SYMBOL(tty_register_driver);
3482 * Called by a tty driver to unregister itself.
3484 int tty_unregister_driver(struct tty_driver *driver)
3488 if (driver->refcount)
3491 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3493 mutex_lock(&tty_mutex);
3494 list_del(&driver->tty_drivers);
3495 mutex_unlock(&tty_mutex);
3499 EXPORT_SYMBOL(tty_unregister_driver);
3501 dev_t tty_devnum(struct tty_struct *tty)
3503 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3505 EXPORT_SYMBOL(tty_devnum);
3507 void tty_default_fops(struct file_operations *fops)
3513 * Initialize the console device. This is called *early*, so
3514 * we can't necessarily depend on lots of kernel help here.
3515 * Just do some early initializations, and do the complex setup
3518 void __init console_init(void)
3522 /* Setup the default TTY line discipline. */
3526 * set up the console device so that later boot sequences can
3527 * inform about problems etc..
3529 call = __con_initcall_start;
3530 while (call < __con_initcall_end) {
3536 static char *tty_devnode(struct device *dev, umode_t *mode)
3540 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3541 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3546 static int __init tty_class_init(void)
3548 tty_class = class_create(THIS_MODULE, "tty");
3549 if (IS_ERR(tty_class))
3550 return PTR_ERR(tty_class);
3551 tty_class->devnode = tty_devnode;
3555 postcore_initcall(tty_class_init);
3557 /* 3/2004 jmc: why do these devices exist? */
3558 static struct cdev tty_cdev, console_cdev;
3560 static ssize_t show_cons_active(struct device *dev,
3561 struct device_attribute *attr, char *buf)
3563 struct console *cs[16];
3569 for_each_console(c) {
3574 if ((c->flags & CON_ENABLED) == 0)
3577 if (i >= ARRAY_SIZE(cs))
3581 int index = cs[i]->index;
3582 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3584 /* don't resolve tty0 as some programs depend on it */
3585 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3586 count += tty_line_name(drv, index, buf + count);
3588 count += sprintf(buf + count, "%s%d",
3589 cs[i]->name, cs[i]->index);
3591 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3597 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3599 static struct device *consdev;
3601 void console_sysfs_notify(void)
3604 sysfs_notify(&consdev->kobj, NULL, "active");
3608 * Ok, now we can initialize the rest of the tty devices and can count
3609 * on memory allocations, interrupts etc..
3611 int __init tty_init(void)
3613 cdev_init(&tty_cdev, &tty_fops);
3614 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3615 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3616 panic("Couldn't register /dev/tty driver\n");
3617 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3619 cdev_init(&console_cdev, &console_fops);
3620 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3621 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3622 panic("Couldn't register /dev/console driver\n");
3623 consdev = device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3625 if (IS_ERR(consdev))
3628 WARN_ON(device_create_file(consdev, &dev_attr_active) < 0);
3631 vty_init(&console_fops);