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/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
, struct tty_struct
*o_tty
,
1708 #ifdef TTY_PARANOIA_CHECK
1709 if (idx
< 0 || idx
>= tty
->driver
->num
) {
1710 printk(KERN_DEBUG
"%s: bad idx when trying to free (%s)\n",
1711 __func__
, tty
->name
);
1715 /* not much to check for devpts */
1716 if (tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
)
1719 if (tty
!= tty
->driver
->ttys
[idx
]) {
1720 printk(KERN_DEBUG
"%s: driver.table[%d] not tty for (%s)\n",
1721 __func__
, idx
, tty
->name
);
1724 if (tty
->driver
->other
) {
1725 if (o_tty
!= tty
->driver
->other
->ttys
[idx
]) {
1726 printk(KERN_DEBUG
"%s: other->table[%d] not o_tty for (%s)\n",
1727 __func__
, idx
, tty
->name
);
1730 if (o_tty
->link
!= tty
) {
1731 printk(KERN_DEBUG
"%s: bad pty pointers\n", __func__
);
1740 * tty_release - vfs callback for close
1741 * @inode: inode of tty
1742 * @filp: file pointer for handle to tty
1744 * Called the last time each file handle is closed that references
1745 * this tty. There may however be several such references.
1748 * Takes bkl. See tty_release_dev
1750 * Even releasing the tty structures is a tricky business.. We have
1751 * to be very careful that the structures are all released at the
1752 * same time, as interrupts might otherwise get the wrong pointers.
1754 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1755 * lead to double frees or releasing memory still in use.
1758 int tty_release(struct inode
*inode
, struct file
*filp
)
1760 struct tty_struct
*tty
= file_tty(filp
);
1761 struct tty_struct
*o_tty
;
1762 int pty_master
, do_sleep
, final
;
1766 if (tty_paranoia_check(tty
, inode
, __func__
))
1770 check_tty_count(tty
, __func__
);
1772 __tty_fasync(-1, filp
, 0);
1775 pty_master
= (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1776 tty
->driver
->subtype
== PTY_TYPE_MASTER
);
1777 /* Review: parallel close */
1780 if (tty_release_checks(tty
, o_tty
, idx
)) {
1785 #ifdef TTY_DEBUG_HANGUP
1786 printk(KERN_DEBUG
"%s: %s (tty count=%d)...\n", __func__
,
1787 tty_name(tty
, buf
), tty
->count
);
1790 if (tty
->ops
->close
)
1791 tty
->ops
->close(tty
, filp
);
1795 * Sanity check: if tty->count is going to zero, there shouldn't be
1796 * any waiters on tty->read_wait or tty->write_wait. We test the
1797 * wait queues and kick everyone out _before_ actually starting to
1798 * close. This ensures that we won't block while releasing the tty
1801 * The test for the o_tty closing is necessary, since the master and
1802 * slave sides may close in any order. If the slave side closes out
1803 * first, its count will be one, since the master side holds an open.
1804 * Thus this test wouldn't be triggered at the time the slave closed,
1807 tty_lock_pair(tty
, o_tty
);
1812 if (tty
->count
<= 1) {
1813 if (waitqueue_active(&tty
->read_wait
)) {
1814 wake_up_poll(&tty
->read_wait
, POLLIN
);
1817 if (waitqueue_active(&tty
->write_wait
)) {
1818 wake_up_poll(&tty
->write_wait
, POLLOUT
);
1822 if (pty_master
&& o_tty
->count
<= 1) {
1823 if (waitqueue_active(&o_tty
->read_wait
)) {
1824 wake_up_poll(&o_tty
->read_wait
, POLLIN
);
1827 if (waitqueue_active(&o_tty
->write_wait
)) {
1828 wake_up_poll(&o_tty
->write_wait
, POLLOUT
);
1835 printk(KERN_WARNING
"%s: %s: read/write wait queue active!\n",
1836 __func__
, tty_name(tty
, buf
));
1841 if (--o_tty
->count
< 0) {
1842 printk(KERN_WARNING
"%s: bad pty slave count (%d) for %s\n",
1843 __func__
, o_tty
->count
, tty_name(o_tty
, buf
));
1847 if (--tty
->count
< 0) {
1848 printk(KERN_WARNING
"%s: bad tty->count (%d) for %s\n",
1849 __func__
, tty
->count
, tty_name(tty
, buf
));
1854 * We've decremented tty->count, so we need to remove this file
1855 * descriptor off the tty->tty_files list; this serves two
1857 * - check_tty_count sees the correct number of file descriptors
1858 * associated with this tty.
1859 * - do_tty_hangup no longer sees this file descriptor as
1860 * something that needs to be handled for hangups.
1865 * Perform some housekeeping before deciding whether to return.
1867 * If _either_ side is closing, make sure there aren't any
1868 * processes that still think tty or o_tty is their controlling
1872 read_lock(&tasklist_lock
);
1873 session_clear_tty(tty
->session
);
1875 session_clear_tty(o_tty
->session
);
1876 read_unlock(&tasklist_lock
);
1879 /* check whether both sides are closing ... */
1880 final
= !tty
->count
&& !(pty_master
&& o_tty
->count
);
1882 tty_unlock_pair(tty
, o_tty
);
1883 /* At this point, the tty->count == 0 should ensure a dead tty
1884 cannot be re-opened by a racing opener */
1889 #ifdef TTY_DEBUG_HANGUP
1890 printk(KERN_DEBUG
"%s: %s: final close\n", __func__
, tty_name(tty
, buf
));
1893 * Ask the line discipline code to release its structures
1895 tty_ldisc_release(tty
, o_tty
);
1897 /* Wait for pending work before tty destruction commmences */
1898 tty_flush_works(tty
);
1900 #ifdef TTY_DEBUG_HANGUP
1901 printk(KERN_DEBUG
"%s: %s: freeing structure...\n", __func__
, tty_name(tty
, buf
));
1904 * The release_tty function takes care of the details of clearing
1905 * the slots and preserving the termios structure. The tty_unlock_pair
1906 * should be safe as we keep a kref while the tty is locked (so the
1907 * unlock never unlocks a freed tty).
1909 mutex_lock(&tty_mutex
);
1910 release_tty(tty
, idx
);
1911 mutex_unlock(&tty_mutex
);
1917 * tty_open_current_tty - get locked tty of current task
1918 * @device: device number
1919 * @filp: file pointer to tty
1920 * @return: locked tty of the current task iff @device is /dev/tty
1922 * Performs a re-open of the current task's controlling tty.
1924 * We cannot return driver and index like for the other nodes because
1925 * devpts will not work then. It expects inodes to be from devpts FS.
1927 static struct tty_struct
*tty_open_current_tty(dev_t device
, struct file
*filp
)
1929 struct tty_struct
*tty
;
1932 if (device
!= MKDEV(TTYAUX_MAJOR
, 0))
1935 tty
= get_current_tty();
1937 return ERR_PTR(-ENXIO
);
1939 filp
->f_flags
|= O_NONBLOCK
; /* Don't let /dev/tty block */
1942 tty_kref_put(tty
); /* safe to drop the kref now */
1944 retval
= tty_reopen(tty
);
1947 tty
= ERR_PTR(retval
);
1953 * tty_lookup_driver - lookup a tty driver for a given device file
1954 * @device: device number
1955 * @filp: file pointer to tty
1956 * @noctty: set if the device should not become a controlling tty
1957 * @index: index for the device in the @return driver
1958 * @return: driver for this inode (with increased refcount)
1960 * If @return is not erroneous, the caller is responsible to decrement the
1961 * refcount by tty_driver_kref_put.
1963 * Locking: tty_mutex protects get_tty_driver
1965 static struct tty_driver
*tty_lookup_driver(dev_t device
, struct file
*filp
,
1966 int *noctty
, int *index
)
1968 struct tty_driver
*driver
;
1972 case MKDEV(TTY_MAJOR
, 0): {
1973 extern struct tty_driver
*console_driver
;
1974 driver
= tty_driver_kref_get(console_driver
);
1975 *index
= fg_console
;
1980 case MKDEV(TTYAUX_MAJOR
, 1): {
1981 struct tty_driver
*console_driver
= console_device(index
);
1982 if (console_driver
) {
1983 driver
= tty_driver_kref_get(console_driver
);
1985 /* Don't let /dev/console block */
1986 filp
->f_flags
|= O_NONBLOCK
;
1991 return ERR_PTR(-ENODEV
);
1994 driver
= get_tty_driver(device
, index
);
1996 return ERR_PTR(-ENODEV
);
2003 * tty_open - open a tty device
2004 * @inode: inode of device file
2005 * @filp: file pointer to tty
2007 * tty_open and tty_release keep up the tty count that contains the
2008 * number of opens done on a tty. We cannot use the inode-count, as
2009 * different inodes might point to the same tty.
2011 * Open-counting is needed for pty masters, as well as for keeping
2012 * track of serial lines: DTR is dropped when the last close happens.
2013 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2015 * The termios state of a pty is reset on first open so that
2016 * settings don't persist across reuse.
2018 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
2019 * tty->count should protect the rest.
2020 * ->siglock protects ->signal/->sighand
2022 * Note: the tty_unlock/lock cases without a ref are only safe due to
2026 static int tty_open(struct inode
*inode
, struct file
*filp
)
2028 struct tty_struct
*tty
;
2030 struct tty_driver
*driver
= NULL
;
2032 dev_t device
= inode
->i_rdev
;
2033 unsigned saved_flags
= filp
->f_flags
;
2035 nonseekable_open(inode
, filp
);
2038 retval
= tty_alloc_file(filp
);
2042 noctty
= filp
->f_flags
& O_NOCTTY
;
2046 tty
= tty_open_current_tty(device
, filp
);
2048 mutex_lock(&tty_mutex
);
2049 driver
= tty_lookup_driver(device
, filp
, &noctty
, &index
);
2050 if (IS_ERR(driver
)) {
2051 retval
= PTR_ERR(driver
);
2055 /* check whether we're reopening an existing tty */
2056 tty
= tty_driver_lookup_tty(driver
, inode
, index
);
2058 retval
= PTR_ERR(tty
);
2063 mutex_unlock(&tty_mutex
);
2065 /* safe to drop the kref from tty_driver_lookup_tty() */
2067 retval
= tty_reopen(tty
);
2070 tty
= ERR_PTR(retval
);
2072 } else { /* Returns with the tty_lock held for now */
2073 tty
= tty_init_dev(driver
, index
);
2074 mutex_unlock(&tty_mutex
);
2077 tty_driver_kref_put(driver
);
2081 retval
= PTR_ERR(tty
);
2085 tty_add_file(tty
, filp
);
2087 check_tty_count(tty
, __func__
);
2088 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2089 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
2091 #ifdef TTY_DEBUG_HANGUP
2092 printk(KERN_DEBUG
"%s: opening %s...\n", __func__
, tty
->name
);
2095 retval
= tty
->ops
->open(tty
, filp
);
2098 filp
->f_flags
= saved_flags
;
2100 if (!retval
&& test_bit(TTY_EXCLUSIVE
, &tty
->flags
) &&
2101 !capable(CAP_SYS_ADMIN
))
2105 #ifdef TTY_DEBUG_HANGUP
2106 printk(KERN_DEBUG
"%s: error %d in opening %s...\n", __func__
,
2109 tty_unlock(tty
); /* need to call tty_release without BTM */
2110 tty_release(inode
, filp
);
2111 if (retval
!= -ERESTARTSYS
)
2114 if (signal_pending(current
))
2119 * Need to reset f_op in case a hangup happened.
2121 if (filp
->f_op
== &hung_up_tty_fops
)
2122 filp
->f_op
= &tty_fops
;
2125 clear_bit(TTY_HUPPED
, &tty
->flags
);
2128 read_lock(&tasklist_lock
);
2129 spin_lock_irq(¤t
->sighand
->siglock
);
2131 current
->signal
->leader
&&
2132 !current
->signal
->tty
&&
2133 tty
->session
== NULL
)
2134 __proc_set_tty(tty
);
2135 spin_unlock_irq(¤t
->sighand
->siglock
);
2136 read_unlock(&tasklist_lock
);
2140 mutex_unlock(&tty_mutex
);
2141 /* after locks to avoid deadlock */
2142 if (!IS_ERR_OR_NULL(driver
))
2143 tty_driver_kref_put(driver
);
2145 tty_free_file(filp
);
2152 * tty_poll - check tty status
2153 * @filp: file being polled
2154 * @wait: poll wait structures to update
2156 * Call the line discipline polling method to obtain the poll
2157 * status of the device.
2159 * Locking: locks called line discipline but ldisc poll method
2160 * may be re-entered freely by other callers.
2163 static unsigned int tty_poll(struct file
*filp
, poll_table
*wait
)
2165 struct tty_struct
*tty
= file_tty(filp
);
2166 struct tty_ldisc
*ld
;
2169 if (tty_paranoia_check(tty
, file_inode(filp
), "tty_poll"))
2172 ld
= tty_ldisc_ref_wait(tty
);
2174 ret
= (ld
->ops
->poll
)(tty
, filp
, wait
);
2175 tty_ldisc_deref(ld
);
2179 static int __tty_fasync(int fd
, struct file
*filp
, int on
)
2181 struct tty_struct
*tty
= file_tty(filp
);
2182 struct tty_ldisc
*ldisc
;
2183 unsigned long flags
;
2186 if (tty_paranoia_check(tty
, file_inode(filp
), "tty_fasync"))
2189 retval
= fasync_helper(fd
, filp
, on
, &tty
->fasync
);
2193 ldisc
= tty_ldisc_ref(tty
);
2195 if (ldisc
->ops
->fasync
)
2196 ldisc
->ops
->fasync(tty
, on
);
2197 tty_ldisc_deref(ldisc
);
2204 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2207 type
= PIDTYPE_PGID
;
2209 pid
= task_pid(current
);
2213 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2214 __f_setown(filp
, pid
, type
, 0);
2222 static int tty_fasync(int fd
, struct file
*filp
, int on
)
2224 struct tty_struct
*tty
= file_tty(filp
);
2228 retval
= __tty_fasync(fd
, filp
, on
);
2235 * tiocsti - fake input character
2236 * @tty: tty to fake input into
2237 * @p: pointer to character
2239 * Fake input to a tty device. Does the necessary locking and
2242 * FIXME: does not honour flow control ??
2245 * Called functions take tty_ldiscs_lock
2246 * current->signal->tty check is safe without locks
2248 * FIXME: may race normal receive processing
2251 static int tiocsti(struct tty_struct
*tty
, char __user
*p
)
2254 struct tty_ldisc
*ld
;
2256 if ((current
->signal
->tty
!= tty
) && !capable(CAP_SYS_ADMIN
))
2258 if (get_user(ch
, p
))
2260 tty_audit_tiocsti(tty
, ch
);
2261 ld
= tty_ldisc_ref_wait(tty
);
2262 ld
->ops
->receive_buf(tty
, &ch
, &mbz
, 1);
2263 tty_ldisc_deref(ld
);
2268 * tiocgwinsz - implement window query ioctl
2270 * @arg: user buffer for result
2272 * Copies the kernel idea of the window size into the user buffer.
2274 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2278 static int tiocgwinsz(struct tty_struct
*tty
, struct winsize __user
*arg
)
2282 mutex_lock(&tty
->winsize_mutex
);
2283 err
= copy_to_user(arg
, &tty
->winsize
, sizeof(*arg
));
2284 mutex_unlock(&tty
->winsize_mutex
);
2286 return err
? -EFAULT
: 0;
2290 * tty_do_resize - resize event
2291 * @tty: tty being resized
2292 * @rows: rows (character)
2293 * @cols: cols (character)
2295 * Update the termios variables and send the necessary signals to
2296 * peform a terminal resize correctly
2299 int tty_do_resize(struct tty_struct
*tty
, struct winsize
*ws
)
2304 mutex_lock(&tty
->winsize_mutex
);
2305 if (!memcmp(ws
, &tty
->winsize
, sizeof(*ws
)))
2308 /* Signal the foreground process group */
2309 pgrp
= tty_get_pgrp(tty
);
2311 kill_pgrp(pgrp
, SIGWINCH
, 1);
2316 mutex_unlock(&tty
->winsize_mutex
);
2319 EXPORT_SYMBOL(tty_do_resize
);
2322 * tiocswinsz - implement window size set ioctl
2323 * @tty; tty side of tty
2324 * @arg: user buffer for result
2326 * Copies the user idea of the window size to the kernel. Traditionally
2327 * this is just advisory information but for the Linux console it
2328 * actually has driver level meaning and triggers a VC resize.
2331 * Driver dependent. The default do_resize method takes the
2332 * tty termios mutex and ctrl_lock. The console takes its own lock
2333 * then calls into the default method.
2336 static int tiocswinsz(struct tty_struct
*tty
, struct winsize __user
*arg
)
2338 struct winsize tmp_ws
;
2339 if (copy_from_user(&tmp_ws
, arg
, sizeof(*arg
)))
2342 if (tty
->ops
->resize
)
2343 return tty
->ops
->resize(tty
, &tmp_ws
);
2345 return tty_do_resize(tty
, &tmp_ws
);
2349 * tioccons - allow admin to move logical console
2350 * @file: the file to become console
2352 * Allow the administrator to move the redirected console device
2354 * Locking: uses redirect_lock to guard the redirect information
2357 static int tioccons(struct file
*file
)
2359 if (!capable(CAP_SYS_ADMIN
))
2361 if (file
->f_op
->write
== redirected_tty_write
) {
2363 spin_lock(&redirect_lock
);
2366 spin_unlock(&redirect_lock
);
2371 spin_lock(&redirect_lock
);
2373 spin_unlock(&redirect_lock
);
2376 redirect
= get_file(file
);
2377 spin_unlock(&redirect_lock
);
2382 * fionbio - non blocking ioctl
2383 * @file: file to set blocking value
2384 * @p: user parameter
2386 * Historical tty interfaces had a blocking control ioctl before
2387 * the generic functionality existed. This piece of history is preserved
2388 * in the expected tty API of posix OS's.
2390 * Locking: none, the open file handle ensures it won't go away.
2393 static int fionbio(struct file
*file
, int __user
*p
)
2397 if (get_user(nonblock
, p
))
2400 spin_lock(&file
->f_lock
);
2402 file
->f_flags
|= O_NONBLOCK
;
2404 file
->f_flags
&= ~O_NONBLOCK
;
2405 spin_unlock(&file
->f_lock
);
2410 * tiocsctty - set controlling tty
2411 * @tty: tty structure
2412 * @arg: user argument
2414 * This ioctl is used to manage job control. It permits a session
2415 * leader to set this tty as the controlling tty for the session.
2418 * Takes tty_lock() to serialize proc_set_tty() for this tty
2419 * Takes tasklist_lock internally to walk sessions
2420 * Takes ->siglock() when updating signal->tty
2423 static int tiocsctty(struct tty_struct
*tty
, int arg
)
2428 read_lock(&tasklist_lock
);
2430 if (current
->signal
->leader
&& (task_session(current
) == tty
->session
))
2434 * The process must be a session leader and
2435 * not have a controlling tty already.
2437 if (!current
->signal
->leader
|| current
->signal
->tty
) {
2444 * This tty is already the controlling
2445 * tty for another session group!
2447 if (arg
== 1 && capable(CAP_SYS_ADMIN
)) {
2451 session_clear_tty(tty
->session
);
2459 read_unlock(&tasklist_lock
);
2465 * tty_get_pgrp - return a ref counted pgrp pid
2468 * Returns a refcounted instance of the pid struct for the process
2469 * group controlling the tty.
2472 struct pid
*tty_get_pgrp(struct tty_struct
*tty
)
2474 unsigned long flags
;
2477 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2478 pgrp
= get_pid(tty
->pgrp
);
2479 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2483 EXPORT_SYMBOL_GPL(tty_get_pgrp
);
2486 * This checks not only the pgrp, but falls back on the pid if no
2487 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
2490 * The caller must hold rcu lock or the tasklist lock.
2492 static struct pid
*session_of_pgrp(struct pid
*pgrp
)
2494 struct task_struct
*p
;
2495 struct pid
*sid
= NULL
;
2497 p
= pid_task(pgrp
, PIDTYPE_PGID
);
2499 p
= pid_task(pgrp
, PIDTYPE_PID
);
2501 sid
= task_session(p
);
2507 * tiocgpgrp - get process group
2508 * @tty: tty passed by user
2509 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2512 * Obtain the process group of the tty. If there is no process group
2515 * Locking: none. Reference to current->signal->tty is safe.
2518 static int tiocgpgrp(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
2523 * (tty == real_tty) is a cheap way of
2524 * testing if the tty is NOT a master pty.
2526 if (tty
== real_tty
&& current
->signal
->tty
!= real_tty
)
2528 pid
= tty_get_pgrp(real_tty
);
2529 ret
= put_user(pid_vnr(pid
), p
);
2535 * tiocspgrp - attempt to set process group
2536 * @tty: tty passed by user
2537 * @real_tty: tty side device matching tty passed by user
2540 * Set the process group of the tty to the session passed. Only
2541 * permitted where the tty session is our session.
2543 * Locking: RCU, ctrl lock
2546 static int tiocspgrp(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
2550 int retval
= tty_check_change(real_tty
);
2551 unsigned long flags
;
2557 if (!current
->signal
->tty
||
2558 (current
->signal
->tty
!= real_tty
) ||
2559 (real_tty
->session
!= task_session(current
)))
2561 if (get_user(pgrp_nr
, p
))
2566 pgrp
= find_vpid(pgrp_nr
);
2571 if (session_of_pgrp(pgrp
) != task_session(current
))
2574 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2575 put_pid(real_tty
->pgrp
);
2576 real_tty
->pgrp
= get_pid(pgrp
);
2577 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2584 * tiocgsid - get session id
2585 * @tty: tty passed by user
2586 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2587 * @p: pointer to returned session id
2589 * Obtain the session id of the tty. If there is no session
2592 * Locking: none. Reference to current->signal->tty is safe.
2595 static int tiocgsid(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
2598 * (tty == real_tty) is a cheap way of
2599 * testing if the tty is NOT a master pty.
2601 if (tty
== real_tty
&& current
->signal
->tty
!= real_tty
)
2603 if (!real_tty
->session
)
2605 return put_user(pid_vnr(real_tty
->session
), p
);
2609 * tiocsetd - set line discipline
2611 * @p: pointer to user data
2613 * Set the line discipline according to user request.
2615 * Locking: see tty_set_ldisc, this function is just a helper
2618 static int tiocsetd(struct tty_struct
*tty
, int __user
*p
)
2623 if (get_user(ldisc
, p
))
2626 ret
= tty_set_ldisc(tty
, ldisc
);
2632 * send_break - performed time break
2633 * @tty: device to break on
2634 * @duration: timeout in mS
2636 * Perform a timed break on hardware that lacks its own driver level
2637 * timed break functionality.
2640 * atomic_write_lock serializes
2644 static int send_break(struct tty_struct
*tty
, unsigned int duration
)
2648 if (tty
->ops
->break_ctl
== NULL
)
2651 if (tty
->driver
->flags
& TTY_DRIVER_HARDWARE_BREAK
)
2652 retval
= tty
->ops
->break_ctl(tty
, duration
);
2654 /* Do the work ourselves */
2655 if (tty_write_lock(tty
, 0) < 0)
2657 retval
= tty
->ops
->break_ctl(tty
, -1);
2660 if (!signal_pending(current
))
2661 msleep_interruptible(duration
);
2662 retval
= tty
->ops
->break_ctl(tty
, 0);
2664 tty_write_unlock(tty
);
2665 if (signal_pending(current
))
2672 * tty_tiocmget - get modem status
2674 * @file: user file pointer
2675 * @p: pointer to result
2677 * Obtain the modem status bits from the tty driver if the feature
2678 * is supported. Return -EINVAL if it is not available.
2680 * Locking: none (up to the driver)
2683 static int tty_tiocmget(struct tty_struct
*tty
, int __user
*p
)
2685 int retval
= -EINVAL
;
2687 if (tty
->ops
->tiocmget
) {
2688 retval
= tty
->ops
->tiocmget(tty
);
2691 retval
= put_user(retval
, p
);
2697 * tty_tiocmset - set modem status
2699 * @cmd: command - clear bits, set bits or set all
2700 * @p: pointer to desired bits
2702 * Set the modem status bits from the tty driver if the feature
2703 * is supported. Return -EINVAL if it is not available.
2705 * Locking: none (up to the driver)
2708 static int tty_tiocmset(struct tty_struct
*tty
, unsigned int cmd
,
2712 unsigned int set
, clear
, val
;
2714 if (tty
->ops
->tiocmset
== NULL
)
2717 retval
= get_user(val
, p
);
2733 set
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
2734 clear
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
2735 return tty
->ops
->tiocmset(tty
, set
, clear
);
2738 static int tty_tiocgicount(struct tty_struct
*tty
, void __user
*arg
)
2740 int retval
= -EINVAL
;
2741 struct serial_icounter_struct icount
;
2742 memset(&icount
, 0, sizeof(icount
));
2743 if (tty
->ops
->get_icount
)
2744 retval
= tty
->ops
->get_icount(tty
, &icount
);
2747 if (copy_to_user(arg
, &icount
, sizeof(icount
)))
2753 * if pty, return the slave side (real_tty)
2754 * otherwise, return self
2756 static struct tty_struct
*tty_pair_get_tty(struct tty_struct
*tty
)
2758 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2759 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
2765 * Split this up, as gcc can choke on it otherwise..
2767 long tty_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
2769 struct tty_struct
*tty
= file_tty(file
);
2770 struct tty_struct
*real_tty
;
2771 void __user
*p
= (void __user
*)arg
;
2773 struct tty_ldisc
*ld
;
2775 if (tty_paranoia_check(tty
, file_inode(file
), "tty_ioctl"))
2778 real_tty
= tty_pair_get_tty(tty
);
2781 * Factor out some common prep work
2789 retval
= tty_check_change(tty
);
2792 if (cmd
!= TIOCCBRK
) {
2793 tty_wait_until_sent(tty
, 0);
2794 if (signal_pending(current
))
2805 return tiocsti(tty
, p
);
2807 return tiocgwinsz(real_tty
, p
);
2809 return tiocswinsz(real_tty
, p
);
2811 return real_tty
!= tty
? -EINVAL
: tioccons(file
);
2813 return fionbio(file
, p
);
2815 set_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2818 clear_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2822 int excl
= test_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2823 return put_user(excl
, (int __user
*)p
);
2826 if (current
->signal
->tty
!= tty
)
2831 return tiocsctty(tty
, arg
);
2833 return tiocgpgrp(tty
, real_tty
, p
);
2835 return tiocspgrp(tty
, real_tty
, p
);
2837 return tiocgsid(tty
, real_tty
, p
);
2839 return put_user(tty
->ldisc
->ops
->num
, (int __user
*)p
);
2841 return tiocsetd(tty
, p
);
2843 if (!capable(CAP_SYS_ADMIN
))
2849 unsigned int ret
= new_encode_dev(tty_devnum(real_tty
));
2850 return put_user(ret
, (unsigned int __user
*)p
);
2855 case TIOCSBRK
: /* Turn break on, unconditionally */
2856 if (tty
->ops
->break_ctl
)
2857 return tty
->ops
->break_ctl(tty
, -1);
2859 case TIOCCBRK
: /* Turn break off, unconditionally */
2860 if (tty
->ops
->break_ctl
)
2861 return tty
->ops
->break_ctl(tty
, 0);
2863 case TCSBRK
: /* SVID version: non-zero arg --> no break */
2864 /* non-zero arg means wait for all output data
2865 * to be sent (performed above) but don't send break.
2866 * This is used by the tcdrain() termios function.
2869 return send_break(tty
, 250);
2871 case TCSBRKP
: /* support for POSIX tcsendbreak() */
2872 return send_break(tty
, arg
? arg
*100 : 250);
2875 return tty_tiocmget(tty
, p
);
2879 return tty_tiocmset(tty
, cmd
, p
);
2881 retval
= tty_tiocgicount(tty
, p
);
2882 /* For the moment allow fall through to the old method */
2883 if (retval
!= -EINVAL
)
2890 /* flush tty buffer and allow ldisc to process ioctl */
2891 tty_buffer_flush(tty
);
2896 if (tty
->ops
->ioctl
) {
2897 retval
= (tty
->ops
->ioctl
)(tty
, cmd
, arg
);
2898 if (retval
!= -ENOIOCTLCMD
)
2901 ld
= tty_ldisc_ref_wait(tty
);
2903 if (ld
->ops
->ioctl
) {
2904 retval
= ld
->ops
->ioctl(tty
, file
, cmd
, arg
);
2905 if (retval
== -ENOIOCTLCMD
)
2908 tty_ldisc_deref(ld
);
2912 #ifdef CONFIG_COMPAT
2913 static long tty_compat_ioctl(struct file
*file
, unsigned int cmd
,
2916 struct tty_struct
*tty
= file_tty(file
);
2917 struct tty_ldisc
*ld
;
2918 int retval
= -ENOIOCTLCMD
;
2920 if (tty_paranoia_check(tty
, file_inode(file
), "tty_ioctl"))
2923 if (tty
->ops
->compat_ioctl
) {
2924 retval
= (tty
->ops
->compat_ioctl
)(tty
, cmd
, arg
);
2925 if (retval
!= -ENOIOCTLCMD
)
2929 ld
= tty_ldisc_ref_wait(tty
);
2930 if (ld
->ops
->compat_ioctl
)
2931 retval
= ld
->ops
->compat_ioctl(tty
, file
, cmd
, arg
);
2933 retval
= n_tty_compat_ioctl_helper(tty
, file
, cmd
, arg
);
2934 tty_ldisc_deref(ld
);
2940 static int this_tty(const void *t
, struct file
*file
, unsigned fd
)
2942 if (likely(file
->f_op
->read
!= tty_read
))
2944 return file_tty(file
) != t
? 0 : fd
+ 1;
2948 * This implements the "Secure Attention Key" --- the idea is to
2949 * prevent trojan horses by killing all processes associated with this
2950 * tty when the user hits the "Secure Attention Key". Required for
2951 * super-paranoid applications --- see the Orange Book for more details.
2953 * This code could be nicer; ideally it should send a HUP, wait a few
2954 * seconds, then send a INT, and then a KILL signal. But you then
2955 * have to coordinate with the init process, since all processes associated
2956 * with the current tty must be dead before the new getty is allowed
2959 * Now, if it would be correct ;-/ The current code has a nasty hole -
2960 * it doesn't catch files in flight. We may send the descriptor to ourselves
2961 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2963 * Nasty bug: do_SAK is being called in interrupt context. This can
2964 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2966 void __do_SAK(struct tty_struct
*tty
)
2971 struct task_struct
*g
, *p
;
2972 struct pid
*session
;
2977 session
= tty
->session
;
2979 tty_ldisc_flush(tty
);
2981 tty_driver_flush_buffer(tty
);
2983 read_lock(&tasklist_lock
);
2984 /* Kill the entire session */
2985 do_each_pid_task(session
, PIDTYPE_SID
, p
) {
2986 printk(KERN_NOTICE
"SAK: killed process %d"
2987 " (%s): task_session(p)==tty->session\n",
2988 task_pid_nr(p
), p
->comm
);
2989 send_sig(SIGKILL
, p
, 1);
2990 } while_each_pid_task(session
, PIDTYPE_SID
, p
);
2991 /* Now kill any processes that happen to have the
2994 do_each_thread(g
, p
) {
2995 if (p
->signal
->tty
== tty
) {
2996 printk(KERN_NOTICE
"SAK: killed process %d"
2997 " (%s): task_session(p)==tty->session\n",
2998 task_pid_nr(p
), p
->comm
);
2999 send_sig(SIGKILL
, p
, 1);
3003 i
= iterate_fd(p
->files
, 0, this_tty
, tty
);
3005 printk(KERN_NOTICE
"SAK: killed process %d"
3006 " (%s): fd#%d opened to the tty\n",
3007 task_pid_nr(p
), p
->comm
, i
- 1);
3008 force_sig(SIGKILL
, p
);
3011 } while_each_thread(g
, p
);
3012 read_unlock(&tasklist_lock
);
3016 static void do_SAK_work(struct work_struct
*work
)
3018 struct tty_struct
*tty
=
3019 container_of(work
, struct tty_struct
, SAK_work
);
3024 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3025 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3026 * the values which we write to it will be identical to the values which it
3027 * already has. --akpm
3029 void do_SAK(struct tty_struct
*tty
)
3033 schedule_work(&tty
->SAK_work
);
3036 EXPORT_SYMBOL(do_SAK
);
3038 static int dev_match_devt(struct device
*dev
, const void *data
)
3040 const dev_t
*devt
= data
;
3041 return dev
->devt
== *devt
;
3044 /* Must put_device() after it's unused! */
3045 static struct device
*tty_get_device(struct tty_struct
*tty
)
3047 dev_t devt
= tty_devnum(tty
);
3048 return class_find_device(tty_class
, NULL
, &devt
, dev_match_devt
);
3055 * This subroutine allocates and initializes a tty structure.
3057 * Locking: none - tty in question is not exposed at this point
3060 struct tty_struct
*alloc_tty_struct(struct tty_driver
*driver
, int idx
)
3062 struct tty_struct
*tty
;
3064 tty
= kzalloc(sizeof(*tty
), GFP_KERNEL
);
3068 kref_init(&tty
->kref
);
3069 tty
->magic
= TTY_MAGIC
;
3070 tty_ldisc_init(tty
);
3071 tty
->session
= NULL
;
3073 mutex_init(&tty
->legacy_mutex
);
3074 mutex_init(&tty
->throttle_mutex
);
3075 init_rwsem(&tty
->termios_rwsem
);
3076 mutex_init(&tty
->winsize_mutex
);
3077 init_ldsem(&tty
->ldisc_sem
);
3078 init_waitqueue_head(&tty
->write_wait
);
3079 init_waitqueue_head(&tty
->read_wait
);
3080 INIT_WORK(&tty
->hangup_work
, do_tty_hangup
);
3081 mutex_init(&tty
->atomic_write_lock
);
3082 spin_lock_init(&tty
->ctrl_lock
);
3083 spin_lock_init(&tty
->flow_lock
);
3084 INIT_LIST_HEAD(&tty
->tty_files
);
3085 INIT_WORK(&tty
->SAK_work
, do_SAK_work
);
3087 tty
->driver
= driver
;
3088 tty
->ops
= driver
->ops
;
3090 tty_line_name(driver
, idx
, tty
->name
);
3091 tty
->dev
= tty_get_device(tty
);
3097 * deinitialize_tty_struct
3098 * @tty: tty to deinitialize
3100 * This subroutine deinitializes a tty structure that has been newly
3101 * allocated but tty_release cannot be called on that yet.
3103 * Locking: none - tty in question must not be exposed at this point
3105 void deinitialize_tty_struct(struct tty_struct
*tty
)
3107 tty_ldisc_deinit(tty
);
3111 * tty_put_char - write one character to a tty
3115 * Write one byte to the tty using the provided put_char method
3116 * if present. Returns the number of characters successfully output.
3118 * Note: the specific put_char operation in the driver layer may go
3119 * away soon. Don't call it directly, use this method
3122 int tty_put_char(struct tty_struct
*tty
, unsigned char ch
)
3124 if (tty
->ops
->put_char
)
3125 return tty
->ops
->put_char(tty
, ch
);
3126 return tty
->ops
->write(tty
, &ch
, 1);
3128 EXPORT_SYMBOL_GPL(tty_put_char
);
3130 struct class *tty_class
;
3132 static int tty_cdev_add(struct tty_driver
*driver
, dev_t dev
,
3133 unsigned int index
, unsigned int count
)
3135 /* init here, since reused cdevs cause crashes */
3136 cdev_init(&driver
->cdevs
[index
], &tty_fops
);
3137 driver
->cdevs
[index
].owner
= driver
->owner
;
3138 return cdev_add(&driver
->cdevs
[index
], dev
, count
);
3142 * tty_register_device - register a tty device
3143 * @driver: the tty driver that describes the tty device
3144 * @index: the index in the tty driver for this tty device
3145 * @device: a struct device that is associated with this tty device.
3146 * This field is optional, if there is no known struct device
3147 * for this tty device it can be set to NULL safely.
3149 * Returns a pointer to the struct device for this tty device
3150 * (or ERR_PTR(-EFOO) on error).
3152 * This call is required to be made to register an individual tty device
3153 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3154 * that bit is not set, this function should not be called by a tty
3160 struct device
*tty_register_device(struct tty_driver
*driver
, unsigned index
,
3161 struct device
*device
)
3163 return tty_register_device_attr(driver
, index
, device
, NULL
, NULL
);
3165 EXPORT_SYMBOL(tty_register_device
);
3167 static void tty_device_create_release(struct device
*dev
)
3169 pr_debug("device: '%s': %s\n", dev_name(dev
), __func__
);
3174 * tty_register_device_attr - 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.
3180 * @drvdata: Driver data to be set to device.
3181 * @attr_grp: Attribute group to be set on device.
3183 * Returns a pointer to the struct device for this tty device
3184 * (or ERR_PTR(-EFOO) on error).
3186 * This call is required to be made to register an individual tty device
3187 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3188 * that bit is not set, this function should not be called by a tty
3193 struct device
*tty_register_device_attr(struct tty_driver
*driver
,
3194 unsigned index
, struct device
*device
,
3196 const struct attribute_group
**attr_grp
)
3199 dev_t devt
= MKDEV(driver
->major
, driver
->minor_start
) + index
;
3200 struct device
*dev
= NULL
;
3201 int retval
= -ENODEV
;
3204 if (index
>= driver
->num
) {
3205 printk(KERN_ERR
"Attempt to register invalid tty line number "
3207 return ERR_PTR(-EINVAL
);
3210 if (driver
->type
== TTY_DRIVER_TYPE_PTY
)
3211 pty_line_name(driver
, index
, name
);
3213 tty_line_name(driver
, index
, name
);
3215 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
)) {
3216 retval
= tty_cdev_add(driver
, devt
, index
, 1);
3222 dev
= kzalloc(sizeof(*dev
), GFP_KERNEL
);
3229 dev
->class = tty_class
;
3230 dev
->parent
= device
;
3231 dev
->release
= tty_device_create_release
;
3232 dev_set_name(dev
, "%s", name
);
3233 dev
->groups
= attr_grp
;
3234 dev_set_drvdata(dev
, drvdata
);
3236 retval
= device_register(dev
);
3245 cdev_del(&driver
->cdevs
[index
]);
3246 return ERR_PTR(retval
);
3248 EXPORT_SYMBOL_GPL(tty_register_device_attr
);
3251 * tty_unregister_device - unregister a tty device
3252 * @driver: the tty driver that describes the tty device
3253 * @index: the index in the tty driver for this tty device
3255 * If a tty device is registered with a call to tty_register_device() then
3256 * this function must be called when the tty device is gone.
3261 void tty_unregister_device(struct tty_driver
*driver
, unsigned index
)
3263 device_destroy(tty_class
,
3264 MKDEV(driver
->major
, driver
->minor_start
) + index
);
3265 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
))
3266 cdev_del(&driver
->cdevs
[index
]);
3268 EXPORT_SYMBOL(tty_unregister_device
);
3271 * __tty_alloc_driver -- allocate tty driver
3272 * @lines: count of lines this driver can handle at most
3273 * @owner: module which is repsonsible for this driver
3274 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3276 * This should not be called directly, some of the provided macros should be
3277 * used instead. Use IS_ERR and friends on @retval.
3279 struct tty_driver
*__tty_alloc_driver(unsigned int lines
, struct module
*owner
,
3280 unsigned long flags
)
3282 struct tty_driver
*driver
;
3283 unsigned int cdevs
= 1;
3286 if (!lines
|| (flags
& TTY_DRIVER_UNNUMBERED_NODE
&& lines
> 1))
3287 return ERR_PTR(-EINVAL
);
3289 driver
= kzalloc(sizeof(struct tty_driver
), GFP_KERNEL
);
3291 return ERR_PTR(-ENOMEM
);
3293 kref_init(&driver
->kref
);
3294 driver
->magic
= TTY_DRIVER_MAGIC
;
3295 driver
->num
= lines
;
3296 driver
->owner
= owner
;
3297 driver
->flags
= flags
;
3299 if (!(flags
& TTY_DRIVER_DEVPTS_MEM
)) {
3300 driver
->ttys
= kcalloc(lines
, sizeof(*driver
->ttys
),
3302 driver
->termios
= kcalloc(lines
, sizeof(*driver
->termios
),
3304 if (!driver
->ttys
|| !driver
->termios
) {
3310 if (!(flags
& TTY_DRIVER_DYNAMIC_ALLOC
)) {
3311 driver
->ports
= kcalloc(lines
, sizeof(*driver
->ports
),
3313 if (!driver
->ports
) {
3320 driver
->cdevs
= kcalloc(cdevs
, sizeof(*driver
->cdevs
), GFP_KERNEL
);
3321 if (!driver
->cdevs
) {
3328 kfree(driver
->ports
);
3329 kfree(driver
->ttys
);
3330 kfree(driver
->termios
);
3332 return ERR_PTR(err
);
3334 EXPORT_SYMBOL(__tty_alloc_driver
);
3336 static void destruct_tty_driver(struct kref
*kref
)
3338 struct tty_driver
*driver
= container_of(kref
, struct tty_driver
, kref
);
3340 struct ktermios
*tp
;
3342 if (driver
->flags
& TTY_DRIVER_INSTALLED
) {
3344 * Free the termios and termios_locked structures because
3345 * we don't want to get memory leaks when modular tty
3346 * drivers are removed from the kernel.
3348 for (i
= 0; i
< driver
->num
; i
++) {
3349 tp
= driver
->termios
[i
];
3351 driver
->termios
[i
] = NULL
;
3354 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
))
3355 tty_unregister_device(driver
, i
);
3357 proc_tty_unregister_driver(driver
);
3358 if (driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
)
3359 cdev_del(&driver
->cdevs
[0]);
3361 kfree(driver
->cdevs
);
3362 kfree(driver
->ports
);
3363 kfree(driver
->termios
);
3364 kfree(driver
->ttys
);
3368 void tty_driver_kref_put(struct tty_driver
*driver
)
3370 kref_put(&driver
->kref
, destruct_tty_driver
);
3372 EXPORT_SYMBOL(tty_driver_kref_put
);
3374 void tty_set_operations(struct tty_driver
*driver
,
3375 const struct tty_operations
*op
)
3379 EXPORT_SYMBOL(tty_set_operations
);
3381 void put_tty_driver(struct tty_driver
*d
)
3383 tty_driver_kref_put(d
);
3385 EXPORT_SYMBOL(put_tty_driver
);
3388 * Called by a tty driver to register itself.
3390 int tty_register_driver(struct tty_driver
*driver
)
3397 if (!driver
->major
) {
3398 error
= alloc_chrdev_region(&dev
, driver
->minor_start
,
3399 driver
->num
, driver
->name
);
3401 driver
->major
= MAJOR(dev
);
3402 driver
->minor_start
= MINOR(dev
);
3405 dev
= MKDEV(driver
->major
, driver
->minor_start
);
3406 error
= register_chrdev_region(dev
, driver
->num
, driver
->name
);
3411 if (driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
) {
3412 error
= tty_cdev_add(driver
, dev
, 0, driver
->num
);
3414 goto err_unreg_char
;
3417 mutex_lock(&tty_mutex
);
3418 list_add(&driver
->tty_drivers
, &tty_drivers
);
3419 mutex_unlock(&tty_mutex
);
3421 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
)) {
3422 for (i
= 0; i
< driver
->num
; i
++) {
3423 d
= tty_register_device(driver
, i
, NULL
);
3426 goto err_unreg_devs
;
3430 proc_tty_register_driver(driver
);
3431 driver
->flags
|= TTY_DRIVER_INSTALLED
;
3435 for (i
--; i
>= 0; i
--)
3436 tty_unregister_device(driver
, i
);
3438 mutex_lock(&tty_mutex
);
3439 list_del(&driver
->tty_drivers
);
3440 mutex_unlock(&tty_mutex
);
3443 unregister_chrdev_region(dev
, driver
->num
);
3447 EXPORT_SYMBOL(tty_register_driver
);
3450 * Called by a tty driver to unregister itself.
3452 int tty_unregister_driver(struct tty_driver
*driver
)
3456 if (driver
->refcount
)
3459 unregister_chrdev_region(MKDEV(driver
->major
, driver
->minor_start
),
3461 mutex_lock(&tty_mutex
);
3462 list_del(&driver
->tty_drivers
);
3463 mutex_unlock(&tty_mutex
);
3467 EXPORT_SYMBOL(tty_unregister_driver
);
3469 dev_t
tty_devnum(struct tty_struct
*tty
)
3471 return MKDEV(tty
->driver
->major
, tty
->driver
->minor_start
) + tty
->index
;
3473 EXPORT_SYMBOL(tty_devnum
);
3475 void tty_default_fops(struct file_operations
*fops
)
3481 * Initialize the console device. This is called *early*, so
3482 * we can't necessarily depend on lots of kernel help here.
3483 * Just do some early initializations, and do the complex setup
3486 void __init
console_init(void)
3490 /* Setup the default TTY line discipline. */
3494 * set up the console device so that later boot sequences can
3495 * inform about problems etc..
3497 call
= __con_initcall_start
;
3498 while (call
< __con_initcall_end
) {
3504 static char *tty_devnode(struct device
*dev
, umode_t
*mode
)
3508 if (dev
->devt
== MKDEV(TTYAUX_MAJOR
, 0) ||
3509 dev
->devt
== MKDEV(TTYAUX_MAJOR
, 2))
3514 static int __init
tty_class_init(void)
3516 tty_class
= class_create(THIS_MODULE
, "tty");
3517 if (IS_ERR(tty_class
))
3518 return PTR_ERR(tty_class
);
3519 tty_class
->devnode
= tty_devnode
;
3523 postcore_initcall(tty_class_init
);
3525 /* 3/2004 jmc: why do these devices exist? */
3526 static struct cdev tty_cdev
, console_cdev
;
3528 static ssize_t
show_cons_active(struct device
*dev
,
3529 struct device_attribute
*attr
, char *buf
)
3531 struct console
*cs
[16];
3537 for_each_console(c
) {
3542 if ((c
->flags
& CON_ENABLED
) == 0)
3545 if (i
>= ARRAY_SIZE(cs
))
3549 int index
= cs
[i
]->index
;
3550 struct tty_driver
*drv
= cs
[i
]->device(cs
[i
], &index
);
3552 /* don't resolve tty0 as some programs depend on it */
3553 if (drv
&& (cs
[i
]->index
> 0 || drv
->major
!= TTY_MAJOR
))
3554 count
+= tty_line_name(drv
, index
, buf
+ count
);
3556 count
+= sprintf(buf
+ count
, "%s%d",
3557 cs
[i
]->name
, cs
[i
]->index
);
3559 count
+= sprintf(buf
+ count
, "%c", i
? ' ':'\n');
3565 static DEVICE_ATTR(active
, S_IRUGO
, show_cons_active
, NULL
);
3567 static struct device
*consdev
;
3569 void console_sysfs_notify(void)
3572 sysfs_notify(&consdev
->kobj
, NULL
, "active");
3576 * Ok, now we can initialize the rest of the tty devices and can count
3577 * on memory allocations, interrupts etc..
3579 int __init
tty_init(void)
3581 cdev_init(&tty_cdev
, &tty_fops
);
3582 if (cdev_add(&tty_cdev
, MKDEV(TTYAUX_MAJOR
, 0), 1) ||
3583 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 0), 1, "/dev/tty") < 0)
3584 panic("Couldn't register /dev/tty driver\n");
3585 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 0), NULL
, "tty");
3587 cdev_init(&console_cdev
, &console_fops
);
3588 if (cdev_add(&console_cdev
, MKDEV(TTYAUX_MAJOR
, 1), 1) ||
3589 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 1), 1, "/dev/console") < 0)
3590 panic("Couldn't register /dev/console driver\n");
3591 consdev
= device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 1), NULL
,
3593 if (IS_ERR(consdev
))
3596 WARN_ON(device_create_file(consdev
, &dev_attr_active
) < 0);
3599 vty_init(&console_fops
);