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/signal.h>
73 #include <linux/sched/task.h>
74 #include <linux/interrupt.h>
75 #include <linux/tty.h>
76 #include <linux/tty_driver.h>
77 #include <linux/tty_flip.h>
78 #include <linux/devpts_fs.h>
79 #include <linux/file.h>
80 #include <linux/fdtable.h>
81 #include <linux/console.h>
82 #include <linux/timer.h>
83 #include <linux/ctype.h>
86 #include <linux/string.h>
87 #include <linux/slab.h>
88 #include <linux/poll.h>
89 #include <linux/proc_fs.h>
90 #include <linux/init.h>
91 #include <linux/module.h>
92 #include <linux/device.h>
93 #include <linux/wait.h>
94 #include <linux/bitops.h>
95 #include <linux/delay.h>
96 #include <linux/seq_file.h>
97 #include <linux/serial.h>
98 #include <linux/ratelimit.h>
100 #include <linux/uaccess.h>
102 #include <linux/kbd_kern.h>
103 #include <linux/vt_kern.h>
104 #include <linux/selection.h>
106 #include <linux/kmod.h>
107 #include <linux/nsproxy.h>
109 #undef TTY_DEBUG_HANGUP
110 #ifdef TTY_DEBUG_HANGUP
111 # define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args)
113 # define tty_debug_hangup(tty, f, args...) do { } while (0)
116 #define TTY_PARANOIA_CHECK 1
117 #define CHECK_TTY_COUNT 1
119 struct ktermios tty_std_termios
= { /* for the benefit of tty drivers */
120 .c_iflag
= ICRNL
| IXON
,
121 .c_oflag
= OPOST
| ONLCR
,
122 .c_cflag
= B38400
| CS8
| CREAD
| HUPCL
,
123 .c_lflag
= ISIG
| ICANON
| ECHO
| ECHOE
| ECHOK
|
124 ECHOCTL
| ECHOKE
| IEXTEN
,
128 /* .c_line = N_TTY, */
131 EXPORT_SYMBOL(tty_std_termios
);
133 /* This list gets poked at by procfs and various bits of boot up code. This
134 could do with some rationalisation such as pulling the tty proc function
137 LIST_HEAD(tty_drivers
); /* linked list of tty drivers */
139 /* Mutex to protect creating and releasing a tty */
140 DEFINE_MUTEX(tty_mutex
);
142 static ssize_t
tty_read(struct file
*, char __user
*, size_t, loff_t
*);
143 static ssize_t
tty_write(struct file
*, const char __user
*, size_t, loff_t
*);
144 ssize_t
redirected_tty_write(struct file
*, const char __user
*,
146 static unsigned int tty_poll(struct file
*, poll_table
*);
147 static int tty_open(struct inode
*, struct file
*);
148 long tty_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
);
150 static long tty_compat_ioctl(struct file
*file
, unsigned int cmd
,
153 #define tty_compat_ioctl NULL
155 static int __tty_fasync(int fd
, struct file
*filp
, int on
);
156 static int tty_fasync(int fd
, struct file
*filp
, int on
);
157 static void release_tty(struct tty_struct
*tty
, int idx
);
160 * free_tty_struct - free a disused tty
161 * @tty: tty struct to free
163 * Free the write buffers, tty queue and tty memory itself.
165 * Locking: none. Must be called after tty is definitely unused
168 static void free_tty_struct(struct tty_struct
*tty
)
170 tty_ldisc_deinit(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
;
226 struct tty_struct
*tty
= priv
->tty
;
228 spin_lock(&tty
->files_lock
);
229 list_del(&priv
->list
);
230 spin_unlock(&tty
->files_lock
);
235 * tty_name - return tty naming
236 * @tty: tty structure
238 * Convert a tty structure into a name. The name reflects the kernel
239 * naming policy and if udev is in use may not reflect user space
244 const char *tty_name(const struct tty_struct
*tty
)
246 if (!tty
) /* Hmm. NULL pointer. That's fun. */
251 EXPORT_SYMBOL(tty_name
);
253 const char *tty_driver_name(const struct tty_struct
*tty
)
255 if (!tty
|| !tty
->driver
)
257 return tty
->driver
->name
;
260 static int tty_paranoia_check(struct tty_struct
*tty
, struct inode
*inode
,
263 #ifdef TTY_PARANOIA_CHECK
265 pr_warn("(%d:%d): %s: NULL tty\n",
266 imajor(inode
), iminor(inode
), routine
);
269 if (tty
->magic
!= TTY_MAGIC
) {
270 pr_warn("(%d:%d): %s: bad magic number\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
283 int count
= 0, kopen_count
= 0;
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_port_kopened(tty
->port
))
296 if (tty
->count
!= (count
+ kopen_count
)) {
297 tty_warn(tty
, "%s: tty->count(%d) != (#fd's(%d) + #kopen's(%d))\n",
298 routine
, tty
->count
, count
, kopen_count
);
299 return (count
+ kopen_count
);
306 * get_tty_driver - find device of a tty
307 * @dev_t: device identifier
308 * @index: returns the index of the tty
310 * This routine returns a tty driver structure, given a device number
311 * and also passes back the index number.
313 * Locking: caller must hold tty_mutex
316 static struct tty_driver
*get_tty_driver(dev_t device
, int *index
)
318 struct tty_driver
*p
;
320 list_for_each_entry(p
, &tty_drivers
, tty_drivers
) {
321 dev_t base
= MKDEV(p
->major
, p
->minor_start
);
322 if (device
< base
|| device
>= base
+ p
->num
)
324 *index
= device
- base
;
325 return tty_driver_kref_get(p
);
331 * tty_dev_name_to_number - return dev_t for device name
332 * @name: user space name of device under /dev
333 * @number: pointer to dev_t that this function will populate
335 * This function converts device names like ttyS0 or ttyUSB1 into dev_t
336 * like (4, 64) or (188, 1). If no corresponding driver is registered then
337 * the function returns -ENODEV.
339 * Locking: this acquires tty_mutex to protect the tty_drivers list from
340 * being modified while we are traversing it, and makes sure to
341 * release it before exiting.
343 int tty_dev_name_to_number(const char *name
, dev_t
*number
)
345 struct tty_driver
*p
;
347 int index
, prefix_length
= 0;
350 for (str
= name
; *str
&& !isdigit(*str
); str
++)
356 ret
= kstrtoint(str
, 10, &index
);
360 prefix_length
= str
- name
;
361 mutex_lock(&tty_mutex
);
363 list_for_each_entry(p
, &tty_drivers
, tty_drivers
)
364 if (prefix_length
== strlen(p
->name
) && strncmp(name
,
365 p
->name
, prefix_length
) == 0) {
366 if (index
< p
->num
) {
367 *number
= MKDEV(p
->major
, p
->minor_start
+ index
);
372 /* if here then driver wasn't found */
375 mutex_unlock(&tty_mutex
);
378 EXPORT_SYMBOL_GPL(tty_dev_name_to_number
);
380 #ifdef CONFIG_CONSOLE_POLL
383 * tty_find_polling_driver - find device of a polled tty
384 * @name: name string to match
385 * @line: pointer to resulting tty line nr
387 * This routine returns a tty driver structure, given a name
388 * and the condition that the tty driver is capable of polled
391 struct tty_driver
*tty_find_polling_driver(char *name
, int *line
)
393 struct tty_driver
*p
, *res
= NULL
;
398 for (str
= name
; *str
; str
++)
399 if ((*str
>= '0' && *str
<= '9') || *str
== ',')
405 tty_line
= simple_strtoul(str
, &str
, 10);
407 mutex_lock(&tty_mutex
);
408 /* Search through the tty devices to look for a match */
409 list_for_each_entry(p
, &tty_drivers
, tty_drivers
) {
410 if (strncmp(name
, p
->name
, len
) != 0)
418 if (tty_line
>= 0 && tty_line
< p
->num
&& p
->ops
&&
419 p
->ops
->poll_init
&& !p
->ops
->poll_init(p
, tty_line
, stp
)) {
420 res
= tty_driver_kref_get(p
);
425 mutex_unlock(&tty_mutex
);
429 EXPORT_SYMBOL_GPL(tty_find_polling_driver
);
432 static ssize_t
hung_up_tty_read(struct file
*file
, char __user
*buf
,
433 size_t count
, loff_t
*ppos
)
438 static ssize_t
hung_up_tty_write(struct file
*file
, const char __user
*buf
,
439 size_t count
, loff_t
*ppos
)
444 /* No kernel lock held - none needed ;) */
445 static unsigned int hung_up_tty_poll(struct file
*filp
, poll_table
*wait
)
447 return POLLIN
| POLLOUT
| POLLERR
| POLLHUP
| POLLRDNORM
| POLLWRNORM
;
450 static long hung_up_tty_ioctl(struct file
*file
, unsigned int cmd
,
453 return cmd
== TIOCSPGRP
? -ENOTTY
: -EIO
;
456 static long hung_up_tty_compat_ioctl(struct file
*file
,
457 unsigned int cmd
, unsigned long arg
)
459 return cmd
== TIOCSPGRP
? -ENOTTY
: -EIO
;
462 static int hung_up_tty_fasync(int fd
, struct file
*file
, int on
)
467 static void tty_show_fdinfo(struct seq_file
*m
, struct file
*file
)
469 struct tty_struct
*tty
= file_tty(file
);
471 if (tty
&& tty
->ops
&& tty
->ops
->show_fdinfo
)
472 tty
->ops
->show_fdinfo(tty
, m
);
475 static const struct file_operations tty_fops
= {
480 .unlocked_ioctl
= tty_ioctl
,
481 .compat_ioctl
= tty_compat_ioctl
,
483 .release
= tty_release
,
484 .fasync
= tty_fasync
,
485 .show_fdinfo
= tty_show_fdinfo
,
488 static const struct file_operations console_fops
= {
491 .write
= redirected_tty_write
,
493 .unlocked_ioctl
= tty_ioctl
,
494 .compat_ioctl
= tty_compat_ioctl
,
496 .release
= tty_release
,
497 .fasync
= tty_fasync
,
500 static const struct file_operations hung_up_tty_fops
= {
502 .read
= hung_up_tty_read
,
503 .write
= hung_up_tty_write
,
504 .poll
= hung_up_tty_poll
,
505 .unlocked_ioctl
= hung_up_tty_ioctl
,
506 .compat_ioctl
= hung_up_tty_compat_ioctl
,
507 .release
= tty_release
,
508 .fasync
= hung_up_tty_fasync
,
511 static DEFINE_SPINLOCK(redirect_lock
);
512 static struct file
*redirect
;
515 * tty_wakeup - request more data
518 * Internal and external helper for wakeups of tty. This function
519 * informs the line discipline if present that the driver is ready
520 * to receive more output data.
523 void tty_wakeup(struct tty_struct
*tty
)
525 struct tty_ldisc
*ld
;
527 if (test_bit(TTY_DO_WRITE_WAKEUP
, &tty
->flags
)) {
528 ld
= tty_ldisc_ref(tty
);
530 if (ld
->ops
->write_wakeup
)
531 ld
->ops
->write_wakeup(tty
);
535 wake_up_interruptible_poll(&tty
->write_wait
, POLLOUT
);
538 EXPORT_SYMBOL_GPL(tty_wakeup
);
541 * __tty_hangup - actual handler for hangup events
544 * This can be called by a "kworker" kernel thread. That is process
545 * synchronous but doesn't hold any locks, so we need to make sure we
546 * have the appropriate locks for what we're doing.
548 * The hangup event clears any pending redirections onto the hung up
549 * device. It ensures future writes will error and it does the needed
550 * line discipline hangup and signal delivery. The tty object itself
555 * redirect lock for undoing redirection
556 * file list lock for manipulating list of ttys
557 * tty_ldiscs_lock from called functions
558 * termios_rwsem resetting termios data
559 * tasklist_lock to walk task list for hangup event
560 * ->siglock to protect ->signal/->sighand
562 static void __tty_hangup(struct tty_struct
*tty
, int exit_session
)
564 struct file
*cons_filp
= NULL
;
565 struct file
*filp
, *f
= NULL
;
566 struct tty_file_private
*priv
;
567 int closecount
= 0, n
;
574 spin_lock(&redirect_lock
);
575 if (redirect
&& file_tty(redirect
) == tty
) {
579 spin_unlock(&redirect_lock
);
583 if (test_bit(TTY_HUPPED
, &tty
->flags
)) {
588 /* inuse_filps is protected by the single tty lock,
589 this really needs to change if we want to flush the
590 workqueue with the lock held */
591 check_tty_count(tty
, "tty_hangup");
593 spin_lock(&tty
->files_lock
);
594 /* This breaks for file handles being sent over AF_UNIX sockets ? */
595 list_for_each_entry(priv
, &tty
->tty_files
, list
) {
597 if (filp
->f_op
->write
== redirected_tty_write
)
599 if (filp
->f_op
->write
!= tty_write
)
602 __tty_fasync(-1, filp
, 0); /* can't block */
603 filp
->f_op
= &hung_up_tty_fops
;
605 spin_unlock(&tty
->files_lock
);
607 refs
= tty_signal_session_leader(tty
, exit_session
);
608 /* Account for the p->signal references we killed */
612 tty_ldisc_hangup(tty
, cons_filp
!= NULL
);
614 spin_lock_irq(&tty
->ctrl_lock
);
615 clear_bit(TTY_THROTTLED
, &tty
->flags
);
616 clear_bit(TTY_DO_WRITE_WAKEUP
, &tty
->flags
);
617 put_pid(tty
->session
);
621 tty
->ctrl_status
= 0;
622 spin_unlock_irq(&tty
->ctrl_lock
);
625 * If one of the devices matches a console pointer, we
626 * cannot just call hangup() because that will cause
627 * tty->count and state->count to go out of sync.
628 * So we just call close() the right number of times.
632 for (n
= 0; n
< closecount
; n
++)
633 tty
->ops
->close(tty
, cons_filp
);
634 } else if (tty
->ops
->hangup
)
635 tty
->ops
->hangup(tty
);
637 * We don't want to have driver/ldisc interactions beyond the ones
638 * we did here. The driver layer expects no calls after ->hangup()
639 * from the ldisc side, which is now guaranteed.
641 set_bit(TTY_HUPPED
, &tty
->flags
);
648 static void do_tty_hangup(struct work_struct
*work
)
650 struct tty_struct
*tty
=
651 container_of(work
, struct tty_struct
, hangup_work
);
653 __tty_hangup(tty
, 0);
657 * tty_hangup - trigger a hangup event
658 * @tty: tty to hangup
660 * A carrier loss (virtual or otherwise) has occurred on this like
661 * schedule a hangup sequence to run after this event.
664 void tty_hangup(struct tty_struct
*tty
)
666 tty_debug_hangup(tty
, "hangup\n");
667 schedule_work(&tty
->hangup_work
);
670 EXPORT_SYMBOL(tty_hangup
);
673 * tty_vhangup - process vhangup
674 * @tty: tty to hangup
676 * The user has asked via system call for the terminal to be hung up.
677 * We do this synchronously so that when the syscall returns the process
678 * is complete. That guarantee is necessary for security reasons.
681 void tty_vhangup(struct tty_struct
*tty
)
683 tty_debug_hangup(tty
, "vhangup\n");
684 __tty_hangup(tty
, 0);
687 EXPORT_SYMBOL(tty_vhangup
);
691 * tty_vhangup_self - process vhangup for own ctty
693 * Perform a vhangup on the current controlling tty
696 void tty_vhangup_self(void)
698 struct tty_struct
*tty
;
700 tty
= get_current_tty();
708 * tty_vhangup_session - hangup session leader exit
709 * @tty: tty to hangup
711 * The session leader is exiting and hanging up its controlling terminal.
712 * Every process in the foreground process group is signalled SIGHUP.
714 * We do this synchronously so that when the syscall returns the process
715 * is complete. That guarantee is necessary for security reasons.
718 void tty_vhangup_session(struct tty_struct
*tty
)
720 tty_debug_hangup(tty
, "session hangup\n");
721 __tty_hangup(tty
, 1);
725 * tty_hung_up_p - was tty hung up
726 * @filp: file pointer of tty
728 * Return true if the tty has been subject to a vhangup or a carrier
732 int tty_hung_up_p(struct file
*filp
)
734 return (filp
&& filp
->f_op
== &hung_up_tty_fops
);
737 EXPORT_SYMBOL(tty_hung_up_p
);
740 * stop_tty - propagate flow control
743 * Perform flow control to the driver. May be called
744 * on an already stopped device and will not re-call the driver
747 * This functionality is used by both the line disciplines for
748 * halting incoming flow and by the driver. It may therefore be
749 * called from any context, may be under the tty atomic_write_lock
756 void __stop_tty(struct tty_struct
*tty
)
765 void stop_tty(struct tty_struct
*tty
)
769 spin_lock_irqsave(&tty
->flow_lock
, flags
);
771 spin_unlock_irqrestore(&tty
->flow_lock
, flags
);
773 EXPORT_SYMBOL(stop_tty
);
776 * start_tty - propagate flow control
779 * Start a tty that has been stopped if at all possible. If this
780 * tty was previous stopped and is now being started, the driver
781 * start method is invoked and the line discipline woken.
787 void __start_tty(struct tty_struct
*tty
)
789 if (!tty
->stopped
|| tty
->flow_stopped
)
793 tty
->ops
->start(tty
);
797 void start_tty(struct tty_struct
*tty
)
801 spin_lock_irqsave(&tty
->flow_lock
, flags
);
803 spin_unlock_irqrestore(&tty
->flow_lock
, flags
);
805 EXPORT_SYMBOL(start_tty
);
807 static void tty_update_time(struct timespec
*time
)
809 unsigned long sec
= get_seconds();
812 * We only care if the two values differ in anything other than the
813 * lower three bits (i.e every 8 seconds). If so, then we can update
814 * the time of the tty device, otherwise it could be construded as a
815 * security leak to let userspace know the exact timing of the tty.
817 if ((sec
^ time
->tv_sec
) & ~7)
822 * tty_read - read method for tty device files
823 * @file: pointer to tty file
825 * @count: size of user buffer
828 * Perform the read system call function on this terminal device. Checks
829 * for hung up devices before calling the line discipline method.
832 * Locks the line discipline internally while needed. Multiple
833 * read calls may be outstanding in parallel.
836 static ssize_t
tty_read(struct file
*file
, char __user
*buf
, size_t count
,
840 struct inode
*inode
= file_inode(file
);
841 struct tty_struct
*tty
= file_tty(file
);
842 struct tty_ldisc
*ld
;
844 if (tty_paranoia_check(tty
, inode
, "tty_read"))
846 if (!tty
|| tty_io_error(tty
))
849 /* We want to wait for the line discipline to sort out in this
851 ld
= tty_ldisc_ref_wait(tty
);
853 return hung_up_tty_read(file
, buf
, count
, ppos
);
855 i
= ld
->ops
->read(tty
, file
, buf
, count
);
861 tty_update_time(&inode
->i_atime
);
866 static void tty_write_unlock(struct tty_struct
*tty
)
868 mutex_unlock(&tty
->atomic_write_lock
);
869 wake_up_interruptible_poll(&tty
->write_wait
, POLLOUT
);
872 static int tty_write_lock(struct tty_struct
*tty
, int ndelay
)
874 if (!mutex_trylock(&tty
->atomic_write_lock
)) {
877 if (mutex_lock_interruptible(&tty
->atomic_write_lock
))
884 * Split writes up in sane blocksizes to avoid
885 * denial-of-service type attacks
887 static inline ssize_t
do_tty_write(
888 ssize_t (*write
)(struct tty_struct
*, struct file
*, const unsigned char *, size_t),
889 struct tty_struct
*tty
,
891 const char __user
*buf
,
894 ssize_t ret
, written
= 0;
897 ret
= tty_write_lock(tty
, file
->f_flags
& O_NDELAY
);
902 * We chunk up writes into a temporary buffer. This
903 * simplifies low-level drivers immensely, since they
904 * don't have locking issues and user mode accesses.
906 * But if TTY_NO_WRITE_SPLIT is set, we should use a
909 * The default chunk-size is 2kB, because the NTTY
910 * layer has problems with bigger chunks. It will
911 * claim to be able to handle more characters than
914 * FIXME: This can probably go away now except that 64K chunks
915 * are too likely to fail unless switched to vmalloc...
918 if (test_bit(TTY_NO_WRITE_SPLIT
, &tty
->flags
))
923 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
924 if (tty
->write_cnt
< chunk
) {
925 unsigned char *buf_chunk
;
930 buf_chunk
= kmalloc(chunk
, GFP_KERNEL
);
935 kfree(tty
->write_buf
);
936 tty
->write_cnt
= chunk
;
937 tty
->write_buf
= buf_chunk
;
940 /* Do the write .. */
946 if (copy_from_user(tty
->write_buf
, buf
, size
))
948 ret
= write(tty
, file
, tty
->write_buf
, size
);
957 if (signal_pending(current
))
962 tty_update_time(&file_inode(file
)->i_mtime
);
966 tty_write_unlock(tty
);
971 * tty_write_message - write a message to a certain tty, not just the console.
972 * @tty: the destination tty_struct
973 * @msg: the message to write
975 * This is used for messages that need to be redirected to a specific tty.
976 * We don't put it into the syslog queue right now maybe in the future if
979 * We must still hold the BTM and test the CLOSING flag for the moment.
982 void tty_write_message(struct tty_struct
*tty
, char *msg
)
985 mutex_lock(&tty
->atomic_write_lock
);
987 if (tty
->ops
->write
&& tty
->count
> 0)
988 tty
->ops
->write(tty
, msg
, strlen(msg
));
990 tty_write_unlock(tty
);
997 * tty_write - write method for tty device file
998 * @file: tty file pointer
999 * @buf: user data to write
1000 * @count: bytes to write
1003 * Write data to a tty device via the line discipline.
1006 * Locks the line discipline as required
1007 * Writes to the tty driver are serialized by the atomic_write_lock
1008 * and are then processed in chunks to the device. The line discipline
1009 * write method will not be invoked in parallel for each device.
1012 static ssize_t
tty_write(struct file
*file
, const char __user
*buf
,
1013 size_t count
, loff_t
*ppos
)
1015 struct tty_struct
*tty
= file_tty(file
);
1016 struct tty_ldisc
*ld
;
1019 if (tty_paranoia_check(tty
, file_inode(file
), "tty_write"))
1021 if (!tty
|| !tty
->ops
->write
|| tty_io_error(tty
))
1023 /* Short term debug to catch buggy drivers */
1024 if (tty
->ops
->write_room
== NULL
)
1025 tty_err(tty
, "missing write_room method\n");
1026 ld
= tty_ldisc_ref_wait(tty
);
1028 return hung_up_tty_write(file
, buf
, count
, ppos
);
1029 if (!ld
->ops
->write
)
1032 ret
= do_tty_write(ld
->ops
->write
, tty
, file
, buf
, count
);
1033 tty_ldisc_deref(ld
);
1037 ssize_t
redirected_tty_write(struct file
*file
, const char __user
*buf
,
1038 size_t count
, loff_t
*ppos
)
1040 struct file
*p
= NULL
;
1042 spin_lock(&redirect_lock
);
1044 p
= get_file(redirect
);
1045 spin_unlock(&redirect_lock
);
1049 res
= vfs_write(p
, buf
, count
, &p
->f_pos
);
1053 return tty_write(file
, buf
, count
, ppos
);
1057 * tty_send_xchar - send priority character
1059 * Send a high priority character to the tty even if stopped
1061 * Locking: none for xchar method, write ordering for write method.
1064 int tty_send_xchar(struct tty_struct
*tty
, char ch
)
1066 int was_stopped
= tty
->stopped
;
1068 if (tty
->ops
->send_xchar
) {
1069 down_read(&tty
->termios_rwsem
);
1070 tty
->ops
->send_xchar(tty
, ch
);
1071 up_read(&tty
->termios_rwsem
);
1075 if (tty_write_lock(tty
, 0) < 0)
1076 return -ERESTARTSYS
;
1078 down_read(&tty
->termios_rwsem
);
1081 tty
->ops
->write(tty
, &ch
, 1);
1084 up_read(&tty
->termios_rwsem
);
1085 tty_write_unlock(tty
);
1089 static char ptychar
[] = "pqrstuvwxyzabcde";
1092 * pty_line_name - generate name for a pty
1093 * @driver: the tty driver in use
1094 * @index: the minor number
1095 * @p: output buffer of at least 6 bytes
1097 * Generate a name from a driver reference and write it to the output
1102 static void pty_line_name(struct tty_driver
*driver
, int index
, char *p
)
1104 int i
= index
+ driver
->name_base
;
1105 /* ->name is initialized to "ttyp", but "tty" is expected */
1106 sprintf(p
, "%s%c%x",
1107 driver
->subtype
== PTY_TYPE_SLAVE
? "tty" : driver
->name
,
1108 ptychar
[i
>> 4 & 0xf], i
& 0xf);
1112 * tty_line_name - generate name for a tty
1113 * @driver: the tty driver in use
1114 * @index: the minor number
1115 * @p: output buffer of at least 7 bytes
1117 * Generate a name from a driver reference and write it to the output
1122 static ssize_t
tty_line_name(struct tty_driver
*driver
, int index
, char *p
)
1124 if (driver
->flags
& TTY_DRIVER_UNNUMBERED_NODE
)
1125 return sprintf(p
, "%s", driver
->name
);
1127 return sprintf(p
, "%s%d", driver
->name
,
1128 index
+ driver
->name_base
);
1132 * tty_driver_lookup_tty() - find an existing tty, if any
1133 * @driver: the driver for the tty
1134 * @idx: the minor number
1136 * Return the tty, if found. If not found, return NULL or ERR_PTR() if the
1137 * driver lookup() method returns an error.
1139 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1141 static struct tty_struct
*tty_driver_lookup_tty(struct tty_driver
*driver
,
1142 struct file
*file
, int idx
)
1144 struct tty_struct
*tty
;
1146 if (driver
->ops
->lookup
)
1148 tty
= ERR_PTR(-EIO
);
1150 tty
= driver
->ops
->lookup(driver
, file
, idx
);
1152 tty
= driver
->ttys
[idx
];
1160 * tty_init_termios - helper for termios setup
1161 * @tty: the tty to set up
1163 * Initialise the termios structures for this tty. Thus runs under
1164 * the tty_mutex currently so we can be relaxed about ordering.
1167 void tty_init_termios(struct tty_struct
*tty
)
1169 struct ktermios
*tp
;
1170 int idx
= tty
->index
;
1172 if (tty
->driver
->flags
& TTY_DRIVER_RESET_TERMIOS
)
1173 tty
->termios
= tty
->driver
->init_termios
;
1175 /* Check for lazy saved data */
1176 tp
= tty
->driver
->termios
[idx
];
1179 tty
->termios
.c_line
= tty
->driver
->init_termios
.c_line
;
1181 tty
->termios
= tty
->driver
->init_termios
;
1183 /* Compatibility until drivers always set this */
1184 tty
->termios
.c_ispeed
= tty_termios_input_baud_rate(&tty
->termios
);
1185 tty
->termios
.c_ospeed
= tty_termios_baud_rate(&tty
->termios
);
1187 EXPORT_SYMBOL_GPL(tty_init_termios
);
1189 int tty_standard_install(struct tty_driver
*driver
, struct tty_struct
*tty
)
1191 tty_init_termios(tty
);
1192 tty_driver_kref_get(driver
);
1194 driver
->ttys
[tty
->index
] = tty
;
1197 EXPORT_SYMBOL_GPL(tty_standard_install
);
1200 * tty_driver_install_tty() - install a tty entry in the driver
1201 * @driver: the driver for the tty
1204 * Install a tty object into the driver tables. The tty->index field
1205 * will be set by the time this is called. This method is responsible
1206 * for ensuring any need additional structures are allocated and
1209 * Locking: tty_mutex for now
1211 static int tty_driver_install_tty(struct tty_driver
*driver
,
1212 struct tty_struct
*tty
)
1214 return driver
->ops
->install
? driver
->ops
->install(driver
, tty
) :
1215 tty_standard_install(driver
, tty
);
1219 * tty_driver_remove_tty() - remove a tty from the driver tables
1220 * @driver: the driver for the tty
1221 * @idx: the minor number
1223 * Remvoe a tty object from the driver tables. The tty->index field
1224 * will be set by the time this is called.
1226 * Locking: tty_mutex for now
1228 static void tty_driver_remove_tty(struct tty_driver
*driver
, struct tty_struct
*tty
)
1230 if (driver
->ops
->remove
)
1231 driver
->ops
->remove(driver
, tty
);
1233 driver
->ttys
[tty
->index
] = NULL
;
1237 * tty_reopen() - fast re-open of an open tty
1238 * @tty - the tty to open
1240 * Return 0 on success, -errno on error.
1241 * Re-opens on master ptys are not allowed and return -EIO.
1243 * Locking: Caller must hold tty_lock
1245 static int tty_reopen(struct tty_struct
*tty
)
1247 struct tty_driver
*driver
= tty
->driver
;
1249 if (driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1250 driver
->subtype
== PTY_TYPE_MASTER
)
1256 if (test_bit(TTY_EXCLUSIVE
, &tty
->flags
) && !capable(CAP_SYS_ADMIN
))
1262 return tty_ldisc_reinit(tty
, tty
->termios
.c_line
);
1268 * tty_init_dev - initialise a tty device
1269 * @driver: tty driver we are opening a device on
1270 * @idx: device index
1271 * @ret_tty: returned tty structure
1273 * Prepare a tty device. This may not be a "new" clean device but
1274 * could also be an active device. The pty drivers require special
1275 * handling because of this.
1278 * The function is called under the tty_mutex, which
1279 * protects us from the tty struct or driver itself going away.
1281 * On exit the tty device has the line discipline attached and
1282 * a reference count of 1. If a pair was created for pty/tty use
1283 * and the other was a pty master then it too has a reference count of 1.
1285 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1286 * failed open. The new code protects the open with a mutex, so it's
1287 * really quite straightforward. The mutex locking can probably be
1288 * relaxed for the (most common) case of reopening a tty.
1291 struct tty_struct
*tty_init_dev(struct tty_driver
*driver
, int idx
)
1293 struct tty_struct
*tty
;
1297 * First time open is complex, especially for PTY devices.
1298 * This code guarantees that either everything succeeds and the
1299 * TTY is ready for operation, or else the table slots are vacated
1300 * and the allocated memory released. (Except that the termios
1304 if (!try_module_get(driver
->owner
))
1305 return ERR_PTR(-ENODEV
);
1307 tty
= alloc_tty_struct(driver
, idx
);
1310 goto err_module_put
;
1314 retval
= tty_driver_install_tty(driver
, tty
);
1319 tty
->port
= driver
->ports
[idx
];
1321 WARN_RATELIMIT(!tty
->port
,
1322 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1323 __func__
, tty
->driver
->name
);
1325 retval
= tty_ldisc_lock(tty
, 5 * HZ
);
1327 goto err_release_lock
;
1328 tty
->port
->itty
= tty
;
1331 * Structures all installed ... call the ldisc open routines.
1332 * If we fail here just call release_tty to clean up. No need
1333 * to decrement the use counts, as release_tty doesn't care.
1335 retval
= tty_ldisc_setup(tty
, tty
->link
);
1337 goto err_release_tty
;
1338 tty_ldisc_unlock(tty
);
1339 /* Return the tty locked so that it cannot vanish under the caller */
1344 free_tty_struct(tty
);
1346 module_put(driver
->owner
);
1347 return ERR_PTR(retval
);
1349 /* call the tty release_tty routine to clean out this slot */
1351 tty_ldisc_unlock(tty
);
1352 tty_info_ratelimited(tty
, "ldisc open failed (%d), clearing slot %d\n",
1356 release_tty(tty
, idx
);
1357 return ERR_PTR(retval
);
1360 static void tty_free_termios(struct tty_struct
*tty
)
1362 struct ktermios
*tp
;
1363 int idx
= tty
->index
;
1365 /* If the port is going to reset then it has no termios to save */
1366 if (tty
->driver
->flags
& TTY_DRIVER_RESET_TERMIOS
)
1369 /* Stash the termios data */
1370 tp
= tty
->driver
->termios
[idx
];
1372 tp
= kmalloc(sizeof(struct ktermios
), GFP_KERNEL
);
1375 tty
->driver
->termios
[idx
] = tp
;
1381 * tty_flush_works - flush all works of a tty/pty pair
1382 * @tty: tty device to flush works for (or either end of a pty pair)
1384 * Sync flush all works belonging to @tty (and the 'other' tty).
1386 static void tty_flush_works(struct tty_struct
*tty
)
1388 flush_work(&tty
->SAK_work
);
1389 flush_work(&tty
->hangup_work
);
1391 flush_work(&tty
->link
->SAK_work
);
1392 flush_work(&tty
->link
->hangup_work
);
1397 * release_one_tty - release tty structure memory
1398 * @kref: kref of tty we are obliterating
1400 * Releases memory associated with a tty structure, and clears out the
1401 * driver table slots. This function is called when a device is no longer
1402 * in use. It also gets called when setup of a device fails.
1405 * takes the file list lock internally when working on the list
1406 * of ttys that the driver keeps.
1408 * This method gets called from a work queue so that the driver private
1409 * cleanup ops can sleep (needed for USB at least)
1411 static void release_one_tty(struct work_struct
*work
)
1413 struct tty_struct
*tty
=
1414 container_of(work
, struct tty_struct
, hangup_work
);
1415 struct tty_driver
*driver
= tty
->driver
;
1416 struct module
*owner
= driver
->owner
;
1418 if (tty
->ops
->cleanup
)
1419 tty
->ops
->cleanup(tty
);
1422 tty_driver_kref_put(driver
);
1425 spin_lock(&tty
->files_lock
);
1426 list_del_init(&tty
->tty_files
);
1427 spin_unlock(&tty
->files_lock
);
1430 put_pid(tty
->session
);
1431 free_tty_struct(tty
);
1434 static void queue_release_one_tty(struct kref
*kref
)
1436 struct tty_struct
*tty
= container_of(kref
, struct tty_struct
, kref
);
1438 /* The hangup queue is now free so we can reuse it rather than
1439 waste a chunk of memory for each port */
1440 INIT_WORK(&tty
->hangup_work
, release_one_tty
);
1441 schedule_work(&tty
->hangup_work
);
1445 * tty_kref_put - release a tty kref
1448 * Release a reference to a tty device and if need be let the kref
1449 * layer destruct the object for us
1452 void tty_kref_put(struct tty_struct
*tty
)
1455 kref_put(&tty
->kref
, queue_release_one_tty
);
1457 EXPORT_SYMBOL(tty_kref_put
);
1460 * release_tty - release tty structure memory
1462 * Release both @tty and a possible linked partner (think pty pair),
1463 * and decrement the refcount of the backing module.
1467 * takes the file list lock internally when working on the list
1468 * of ttys that the driver keeps.
1471 static void release_tty(struct tty_struct
*tty
, int idx
)
1473 /* This should always be true but check for the moment */
1474 WARN_ON(tty
->index
!= idx
);
1475 WARN_ON(!mutex_is_locked(&tty_mutex
));
1476 if (tty
->ops
->shutdown
)
1477 tty
->ops
->shutdown(tty
);
1478 tty_free_termios(tty
);
1479 tty_driver_remove_tty(tty
->driver
, tty
);
1480 tty
->port
->itty
= NULL
;
1482 tty
->link
->port
->itty
= NULL
;
1483 tty_buffer_cancel_work(tty
->port
);
1485 tty_buffer_cancel_work(tty
->link
->port
);
1487 tty_kref_put(tty
->link
);
1492 * tty_release_checks - check a tty before real release
1493 * @tty: tty to check
1494 * @o_tty: link of @tty (if any)
1495 * @idx: index of the tty
1497 * Performs some paranoid checking before true release of the @tty.
1498 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1500 static int tty_release_checks(struct tty_struct
*tty
, int idx
)
1502 #ifdef TTY_PARANOIA_CHECK
1503 if (idx
< 0 || idx
>= tty
->driver
->num
) {
1504 tty_debug(tty
, "bad idx %d\n", idx
);
1508 /* not much to check for devpts */
1509 if (tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
)
1512 if (tty
!= tty
->driver
->ttys
[idx
]) {
1513 tty_debug(tty
, "bad driver table[%d] = %p\n",
1514 idx
, tty
->driver
->ttys
[idx
]);
1517 if (tty
->driver
->other
) {
1518 struct tty_struct
*o_tty
= tty
->link
;
1520 if (o_tty
!= tty
->driver
->other
->ttys
[idx
]) {
1521 tty_debug(tty
, "bad other table[%d] = %p\n",
1522 idx
, tty
->driver
->other
->ttys
[idx
]);
1525 if (o_tty
->link
!= tty
) {
1526 tty_debug(tty
, "bad link = %p\n", o_tty
->link
);
1535 * tty_kclose - closes tty opened by tty_kopen
1538 * Performs the final steps to release and free a tty device. It is the
1539 * same as tty_release_struct except that it also resets TTY_PORT_KOPENED
1540 * flag on tty->port.
1542 void tty_kclose(struct tty_struct
*tty
)
1545 * Ask the line discipline code to release its structures
1547 tty_ldisc_release(tty
);
1549 /* Wait for pending work before tty destruction commmences */
1550 tty_flush_works(tty
);
1552 tty_debug_hangup(tty
, "freeing structure\n");
1554 * The release_tty function takes care of the details of clearing
1555 * the slots and preserving the termios structure. The tty_unlock_pair
1556 * should be safe as we keep a kref while the tty is locked (so the
1557 * unlock never unlocks a freed tty).
1559 mutex_lock(&tty_mutex
);
1560 tty_port_set_kopened(tty
->port
, 0);
1561 release_tty(tty
, tty
->index
);
1562 mutex_unlock(&tty_mutex
);
1564 EXPORT_SYMBOL_GPL(tty_kclose
);
1567 * tty_release_struct - release a tty struct
1569 * @idx: index of the tty
1571 * Performs the final steps to release and free a tty device. It is
1572 * roughly the reverse of tty_init_dev.
1574 void tty_release_struct(struct tty_struct
*tty
, int idx
)
1577 * Ask the line discipline code to release its structures
1579 tty_ldisc_release(tty
);
1581 /* Wait for pending work before tty destruction commmences */
1582 tty_flush_works(tty
);
1584 tty_debug_hangup(tty
, "freeing structure\n");
1586 * The release_tty function takes care of the details of clearing
1587 * the slots and preserving the termios structure. The tty_unlock_pair
1588 * should be safe as we keep a kref while the tty is locked (so the
1589 * unlock never unlocks a freed tty).
1591 mutex_lock(&tty_mutex
);
1592 release_tty(tty
, idx
);
1593 mutex_unlock(&tty_mutex
);
1595 EXPORT_SYMBOL_GPL(tty_release_struct
);
1598 * tty_release - vfs callback for close
1599 * @inode: inode of tty
1600 * @filp: file pointer for handle to tty
1602 * Called the last time each file handle is closed that references
1603 * this tty. There may however be several such references.
1606 * Takes bkl. See tty_release_dev
1608 * Even releasing the tty structures is a tricky business.. We have
1609 * to be very careful that the structures are all released at the
1610 * same time, as interrupts might otherwise get the wrong pointers.
1612 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1613 * lead to double frees or releasing memory still in use.
1616 int tty_release(struct inode
*inode
, struct file
*filp
)
1618 struct tty_struct
*tty
= file_tty(filp
);
1619 struct tty_struct
*o_tty
= NULL
;
1620 int do_sleep
, final
;
1625 if (tty_paranoia_check(tty
, inode
, __func__
))
1629 check_tty_count(tty
, __func__
);
1631 __tty_fasync(-1, filp
, 0);
1634 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1635 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
1638 if (tty_release_checks(tty
, idx
)) {
1643 tty_debug_hangup(tty
, "releasing (count=%d)\n", tty
->count
);
1645 if (tty
->ops
->close
)
1646 tty
->ops
->close(tty
, filp
);
1648 /* If tty is pty master, lock the slave pty (stable lock order) */
1649 tty_lock_slave(o_tty
);
1652 * Sanity check: if tty->count is going to zero, there shouldn't be
1653 * any waiters on tty->read_wait or tty->write_wait. We test the
1654 * wait queues and kick everyone out _before_ actually starting to
1655 * close. This ensures that we won't block while releasing the tty
1658 * The test for the o_tty closing is necessary, since the master and
1659 * slave sides may close in any order. If the slave side closes out
1660 * first, its count will be one, since the master side holds an open.
1661 * Thus this test wouldn't be triggered at the time the slave closed,
1667 if (tty
->count
<= 1) {
1668 if (waitqueue_active(&tty
->read_wait
)) {
1669 wake_up_poll(&tty
->read_wait
, POLLIN
);
1672 if (waitqueue_active(&tty
->write_wait
)) {
1673 wake_up_poll(&tty
->write_wait
, POLLOUT
);
1677 if (o_tty
&& o_tty
->count
<= 1) {
1678 if (waitqueue_active(&o_tty
->read_wait
)) {
1679 wake_up_poll(&o_tty
->read_wait
, POLLIN
);
1682 if (waitqueue_active(&o_tty
->write_wait
)) {
1683 wake_up_poll(&o_tty
->write_wait
, POLLOUT
);
1692 tty_warn(tty
, "read/write wait queue active!\n");
1694 schedule_timeout_killable(timeout
);
1695 if (timeout
< 120 * HZ
)
1696 timeout
= 2 * timeout
+ 1;
1698 timeout
= MAX_SCHEDULE_TIMEOUT
;
1702 if (--o_tty
->count
< 0) {
1703 tty_warn(tty
, "bad slave count (%d)\n", o_tty
->count
);
1707 if (--tty
->count
< 0) {
1708 tty_warn(tty
, "bad tty->count (%d)\n", tty
->count
);
1713 * We've decremented tty->count, so we need to remove this file
1714 * descriptor off the tty->tty_files list; this serves two
1716 * - check_tty_count sees the correct number of file descriptors
1717 * associated with this tty.
1718 * - do_tty_hangup no longer sees this file descriptor as
1719 * something that needs to be handled for hangups.
1724 * Perform some housekeeping before deciding whether to return.
1726 * If _either_ side is closing, make sure there aren't any
1727 * processes that still think tty or o_tty is their controlling
1731 read_lock(&tasklist_lock
);
1732 session_clear_tty(tty
->session
);
1734 session_clear_tty(o_tty
->session
);
1735 read_unlock(&tasklist_lock
);
1738 /* check whether both sides are closing ... */
1739 final
= !tty
->count
&& !(o_tty
&& o_tty
->count
);
1741 tty_unlock_slave(o_tty
);
1744 /* At this point, the tty->count == 0 should ensure a dead tty
1745 cannot be re-opened by a racing opener */
1750 tty_debug_hangup(tty
, "final close\n");
1752 tty_release_struct(tty
, idx
);
1757 * tty_open_current_tty - get locked tty of current task
1758 * @device: device number
1759 * @filp: file pointer to tty
1760 * @return: locked tty of the current task iff @device is /dev/tty
1762 * Performs a re-open of the current task's controlling tty.
1764 * We cannot return driver and index like for the other nodes because
1765 * devpts will not work then. It expects inodes to be from devpts FS.
1767 static struct tty_struct
*tty_open_current_tty(dev_t device
, struct file
*filp
)
1769 struct tty_struct
*tty
;
1772 if (device
!= MKDEV(TTYAUX_MAJOR
, 0))
1775 tty
= get_current_tty();
1777 return ERR_PTR(-ENXIO
);
1779 filp
->f_flags
|= O_NONBLOCK
; /* Don't let /dev/tty block */
1782 tty_kref_put(tty
); /* safe to drop the kref now */
1784 retval
= tty_reopen(tty
);
1787 tty
= ERR_PTR(retval
);
1793 * tty_lookup_driver - lookup a tty driver for a given device file
1794 * @device: device number
1795 * @filp: file pointer to tty
1796 * @index: index for the device in the @return driver
1797 * @return: driver for this inode (with increased refcount)
1799 * If @return is not erroneous, the caller is responsible to decrement the
1800 * refcount by tty_driver_kref_put.
1802 * Locking: tty_mutex protects get_tty_driver
1804 static struct tty_driver
*tty_lookup_driver(dev_t device
, struct file
*filp
,
1807 struct tty_driver
*driver
;
1811 case MKDEV(TTY_MAJOR
, 0): {
1812 extern struct tty_driver
*console_driver
;
1813 driver
= tty_driver_kref_get(console_driver
);
1814 *index
= fg_console
;
1818 case MKDEV(TTYAUX_MAJOR
, 1): {
1819 struct tty_driver
*console_driver
= console_device(index
);
1820 if (console_driver
) {
1821 driver
= tty_driver_kref_get(console_driver
);
1822 if (driver
&& filp
) {
1823 /* Don't let /dev/console block */
1824 filp
->f_flags
|= O_NONBLOCK
;
1828 return ERR_PTR(-ENODEV
);
1831 driver
= get_tty_driver(device
, index
);
1833 return ERR_PTR(-ENODEV
);
1840 * tty_kopen - open a tty device for kernel
1841 * @device: dev_t of device to open
1843 * Opens tty exclusively for kernel. Performs the driver lookup,
1844 * makes sure it's not already opened and performs the first-time
1845 * tty initialization.
1847 * Returns the locked initialized &tty_struct
1849 * Claims the global tty_mutex to serialize:
1850 * - concurrent first-time tty initialization
1851 * - concurrent tty driver removal w/ lookup
1852 * - concurrent tty removal from driver table
1854 struct tty_struct
*tty_kopen(dev_t device
)
1856 struct tty_struct
*tty
;
1857 struct tty_driver
*driver
= NULL
;
1860 mutex_lock(&tty_mutex
);
1861 driver
= tty_lookup_driver(device
, NULL
, &index
);
1862 if (IS_ERR(driver
)) {
1863 mutex_unlock(&tty_mutex
);
1864 return ERR_CAST(driver
);
1867 /* check whether we're reopening an existing tty */
1868 tty
= tty_driver_lookup_tty(driver
, NULL
, index
);
1873 /* drop kref from tty_driver_lookup_tty() */
1875 tty
= ERR_PTR(-EBUSY
);
1876 } else { /* tty_init_dev returns tty with the tty_lock held */
1877 tty
= tty_init_dev(driver
, index
);
1880 tty_port_set_kopened(tty
->port
, 1);
1883 mutex_unlock(&tty_mutex
);
1884 tty_driver_kref_put(driver
);
1887 EXPORT_SYMBOL_GPL(tty_kopen
);
1890 * tty_open_by_driver - open a tty device
1891 * @device: dev_t of device to open
1892 * @inode: inode of device file
1893 * @filp: file pointer to tty
1895 * Performs the driver lookup, checks for a reopen, or otherwise
1896 * performs the first-time tty initialization.
1898 * Returns the locked initialized or re-opened &tty_struct
1900 * Claims the global tty_mutex to serialize:
1901 * - concurrent first-time tty initialization
1902 * - concurrent tty driver removal w/ lookup
1903 * - concurrent tty removal from driver table
1905 static struct tty_struct
*tty_open_by_driver(dev_t device
, struct inode
*inode
,
1908 struct tty_struct
*tty
;
1909 struct tty_driver
*driver
= NULL
;
1913 mutex_lock(&tty_mutex
);
1914 driver
= tty_lookup_driver(device
, filp
, &index
);
1915 if (IS_ERR(driver
)) {
1916 mutex_unlock(&tty_mutex
);
1917 return ERR_CAST(driver
);
1920 /* check whether we're reopening an existing tty */
1921 tty
= tty_driver_lookup_tty(driver
, filp
, index
);
1923 mutex_unlock(&tty_mutex
);
1928 if (tty_port_kopened(tty
->port
)) {
1930 mutex_unlock(&tty_mutex
);
1931 tty
= ERR_PTR(-EBUSY
);
1934 mutex_unlock(&tty_mutex
);
1935 retval
= tty_lock_interruptible(tty
);
1936 tty_kref_put(tty
); /* drop kref from tty_driver_lookup_tty() */
1938 if (retval
== -EINTR
)
1939 retval
= -ERESTARTSYS
;
1940 tty
= ERR_PTR(retval
);
1943 retval
= tty_reopen(tty
);
1946 tty
= ERR_PTR(retval
);
1948 } else { /* Returns with the tty_lock held for now */
1949 tty
= tty_init_dev(driver
, index
);
1950 mutex_unlock(&tty_mutex
);
1953 tty_driver_kref_put(driver
);
1958 * tty_open - open a tty device
1959 * @inode: inode of device file
1960 * @filp: file pointer to tty
1962 * tty_open and tty_release keep up the tty count that contains the
1963 * number of opens done on a tty. We cannot use the inode-count, as
1964 * different inodes might point to the same tty.
1966 * Open-counting is needed for pty masters, as well as for keeping
1967 * track of serial lines: DTR is dropped when the last close happens.
1968 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1970 * The termios state of a pty is reset on first open so that
1971 * settings don't persist across reuse.
1973 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
1974 * tty->count should protect the rest.
1975 * ->siglock protects ->signal/->sighand
1977 * Note: the tty_unlock/lock cases without a ref are only safe due to
1981 static int tty_open(struct inode
*inode
, struct file
*filp
)
1983 struct tty_struct
*tty
;
1985 dev_t device
= inode
->i_rdev
;
1986 unsigned saved_flags
= filp
->f_flags
;
1988 nonseekable_open(inode
, filp
);
1991 retval
= tty_alloc_file(filp
);
1995 tty
= tty_open_current_tty(device
, filp
);
1997 tty
= tty_open_by_driver(device
, inode
, filp
);
2000 tty_free_file(filp
);
2001 retval
= PTR_ERR(tty
);
2002 if (retval
!= -EAGAIN
|| signal_pending(current
))
2008 tty_add_file(tty
, filp
);
2010 check_tty_count(tty
, __func__
);
2011 tty_debug_hangup(tty
, "opening (count=%d)\n", tty
->count
);
2014 retval
= tty
->ops
->open(tty
, filp
);
2017 filp
->f_flags
= saved_flags
;
2020 tty_debug_hangup(tty
, "open error %d, releasing\n", retval
);
2022 tty_unlock(tty
); /* need to call tty_release without BTM */
2023 tty_release(inode
, filp
);
2024 if (retval
!= -ERESTARTSYS
)
2027 if (signal_pending(current
))
2032 * Need to reset f_op in case a hangup happened.
2034 if (tty_hung_up_p(filp
))
2035 filp
->f_op
= &tty_fops
;
2038 clear_bit(TTY_HUPPED
, &tty
->flags
);
2040 noctty
= (filp
->f_flags
& O_NOCTTY
) ||
2041 (IS_ENABLED(CONFIG_VT
) && device
== MKDEV(TTY_MAJOR
, 0)) ||
2042 device
== MKDEV(TTYAUX_MAJOR
, 1) ||
2043 (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2044 tty
->driver
->subtype
== PTY_TYPE_MASTER
);
2046 tty_open_proc_set_tty(filp
, tty
);
2054 * tty_poll - check tty status
2055 * @filp: file being polled
2056 * @wait: poll wait structures to update
2058 * Call the line discipline polling method to obtain the poll
2059 * status of the device.
2061 * Locking: locks called line discipline but ldisc poll method
2062 * may be re-entered freely by other callers.
2065 static unsigned int tty_poll(struct file
*filp
, poll_table
*wait
)
2067 struct tty_struct
*tty
= file_tty(filp
);
2068 struct tty_ldisc
*ld
;
2071 if (tty_paranoia_check(tty
, file_inode(filp
), "tty_poll"))
2074 ld
= tty_ldisc_ref_wait(tty
);
2076 return hung_up_tty_poll(filp
, wait
);
2078 ret
= ld
->ops
->poll(tty
, filp
, wait
);
2079 tty_ldisc_deref(ld
);
2083 static int __tty_fasync(int fd
, struct file
*filp
, int on
)
2085 struct tty_struct
*tty
= file_tty(filp
);
2086 unsigned long flags
;
2089 if (tty_paranoia_check(tty
, file_inode(filp
), "tty_fasync"))
2092 retval
= fasync_helper(fd
, filp
, on
, &tty
->fasync
);
2100 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2103 type
= PIDTYPE_PGID
;
2105 pid
= task_pid(current
);
2109 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2110 __f_setown(filp
, pid
, type
, 0);
2118 static int tty_fasync(int fd
, struct file
*filp
, int on
)
2120 struct tty_struct
*tty
= file_tty(filp
);
2121 int retval
= -ENOTTY
;
2124 if (!tty_hung_up_p(filp
))
2125 retval
= __tty_fasync(fd
, filp
, on
);
2132 * tiocsti - fake input character
2133 * @tty: tty to fake input into
2134 * @p: pointer to character
2136 * Fake input to a tty device. Does the necessary locking and
2139 * FIXME: does not honour flow control ??
2142 * Called functions take tty_ldiscs_lock
2143 * current->signal->tty check is safe without locks
2145 * FIXME: may race normal receive processing
2148 static int tiocsti(struct tty_struct
*tty
, char __user
*p
)
2151 struct tty_ldisc
*ld
;
2153 if ((current
->signal
->tty
!= tty
) && !capable(CAP_SYS_ADMIN
))
2155 if (get_user(ch
, p
))
2157 tty_audit_tiocsti(tty
, ch
);
2158 ld
= tty_ldisc_ref_wait(tty
);
2161 ld
->ops
->receive_buf(tty
, &ch
, &mbz
, 1);
2162 tty_ldisc_deref(ld
);
2167 * tiocgwinsz - implement window query ioctl
2169 * @arg: user buffer for result
2171 * Copies the kernel idea of the window size into the user buffer.
2173 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2177 static int tiocgwinsz(struct tty_struct
*tty
, struct winsize __user
*arg
)
2181 mutex_lock(&tty
->winsize_mutex
);
2182 err
= copy_to_user(arg
, &tty
->winsize
, sizeof(*arg
));
2183 mutex_unlock(&tty
->winsize_mutex
);
2185 return err
? -EFAULT
: 0;
2189 * tty_do_resize - resize event
2190 * @tty: tty being resized
2191 * @rows: rows (character)
2192 * @cols: cols (character)
2194 * Update the termios variables and send the necessary signals to
2195 * peform a terminal resize correctly
2198 int tty_do_resize(struct tty_struct
*tty
, struct winsize
*ws
)
2203 mutex_lock(&tty
->winsize_mutex
);
2204 if (!memcmp(ws
, &tty
->winsize
, sizeof(*ws
)))
2207 /* Signal the foreground process group */
2208 pgrp
= tty_get_pgrp(tty
);
2210 kill_pgrp(pgrp
, SIGWINCH
, 1);
2215 mutex_unlock(&tty
->winsize_mutex
);
2218 EXPORT_SYMBOL(tty_do_resize
);
2221 * tiocswinsz - implement window size set ioctl
2222 * @tty; tty side of tty
2223 * @arg: user buffer for result
2225 * Copies the user idea of the window size to the kernel. Traditionally
2226 * this is just advisory information but for the Linux console it
2227 * actually has driver level meaning and triggers a VC resize.
2230 * Driver dependent. The default do_resize method takes the
2231 * tty termios mutex and ctrl_lock. The console takes its own lock
2232 * then calls into the default method.
2235 static int tiocswinsz(struct tty_struct
*tty
, struct winsize __user
*arg
)
2237 struct winsize tmp_ws
;
2238 if (copy_from_user(&tmp_ws
, arg
, sizeof(*arg
)))
2241 if (tty
->ops
->resize
)
2242 return tty
->ops
->resize(tty
, &tmp_ws
);
2244 return tty_do_resize(tty
, &tmp_ws
);
2248 * tioccons - allow admin to move logical console
2249 * @file: the file to become console
2251 * Allow the administrator to move the redirected console device
2253 * Locking: uses redirect_lock to guard the redirect information
2256 static int tioccons(struct file
*file
)
2258 if (!capable(CAP_SYS_ADMIN
))
2260 if (file
->f_op
->write
== redirected_tty_write
) {
2262 spin_lock(&redirect_lock
);
2265 spin_unlock(&redirect_lock
);
2270 spin_lock(&redirect_lock
);
2272 spin_unlock(&redirect_lock
);
2275 redirect
= get_file(file
);
2276 spin_unlock(&redirect_lock
);
2281 * fionbio - non blocking ioctl
2282 * @file: file to set blocking value
2283 * @p: user parameter
2285 * Historical tty interfaces had a blocking control ioctl before
2286 * the generic functionality existed. This piece of history is preserved
2287 * in the expected tty API of posix OS's.
2289 * Locking: none, the open file handle ensures it won't go away.
2292 static int fionbio(struct file
*file
, int __user
*p
)
2296 if (get_user(nonblock
, p
))
2299 spin_lock(&file
->f_lock
);
2301 file
->f_flags
|= O_NONBLOCK
;
2303 file
->f_flags
&= ~O_NONBLOCK
;
2304 spin_unlock(&file
->f_lock
);
2309 * tiocsetd - set line discipline
2311 * @p: pointer to user data
2313 * Set the line discipline according to user request.
2315 * Locking: see tty_set_ldisc, this function is just a helper
2318 static int tiocsetd(struct tty_struct
*tty
, int __user
*p
)
2323 if (get_user(disc
, p
))
2326 ret
= tty_set_ldisc(tty
, disc
);
2332 * tiocgetd - get line discipline
2334 * @p: pointer to user data
2336 * Retrieves the line discipline id directly from the ldisc.
2338 * Locking: waits for ldisc reference (in case the line discipline
2339 * is changing or the tty is being hungup)
2342 static int tiocgetd(struct tty_struct
*tty
, int __user
*p
)
2344 struct tty_ldisc
*ld
;
2347 ld
= tty_ldisc_ref_wait(tty
);
2350 ret
= put_user(ld
->ops
->num
, p
);
2351 tty_ldisc_deref(ld
);
2356 * send_break - performed time break
2357 * @tty: device to break on
2358 * @duration: timeout in mS
2360 * Perform a timed break on hardware that lacks its own driver level
2361 * timed break functionality.
2364 * atomic_write_lock serializes
2368 static int send_break(struct tty_struct
*tty
, unsigned int duration
)
2372 if (tty
->ops
->break_ctl
== NULL
)
2375 if (tty
->driver
->flags
& TTY_DRIVER_HARDWARE_BREAK
)
2376 retval
= tty
->ops
->break_ctl(tty
, duration
);
2378 /* Do the work ourselves */
2379 if (tty_write_lock(tty
, 0) < 0)
2381 retval
= tty
->ops
->break_ctl(tty
, -1);
2384 if (!signal_pending(current
))
2385 msleep_interruptible(duration
);
2386 retval
= tty
->ops
->break_ctl(tty
, 0);
2388 tty_write_unlock(tty
);
2389 if (signal_pending(current
))
2396 * tty_tiocmget - get modem status
2398 * @file: user file pointer
2399 * @p: pointer to result
2401 * Obtain the modem status bits from the tty driver if the feature
2402 * is supported. Return -EINVAL if it is not available.
2404 * Locking: none (up to the driver)
2407 static int tty_tiocmget(struct tty_struct
*tty
, int __user
*p
)
2409 int retval
= -EINVAL
;
2411 if (tty
->ops
->tiocmget
) {
2412 retval
= tty
->ops
->tiocmget(tty
);
2415 retval
= put_user(retval
, p
);
2421 * tty_tiocmset - set modem status
2423 * @cmd: command - clear bits, set bits or set all
2424 * @p: pointer to desired bits
2426 * Set the modem status bits from the tty driver if the feature
2427 * is supported. Return -EINVAL if it is not available.
2429 * Locking: none (up to the driver)
2432 static int tty_tiocmset(struct tty_struct
*tty
, unsigned int cmd
,
2436 unsigned int set
, clear
, val
;
2438 if (tty
->ops
->tiocmset
== NULL
)
2441 retval
= get_user(val
, p
);
2457 set
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
2458 clear
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
2459 return tty
->ops
->tiocmset(tty
, set
, clear
);
2462 static int tty_tiocgicount(struct tty_struct
*tty
, void __user
*arg
)
2464 int retval
= -EINVAL
;
2465 struct serial_icounter_struct icount
;
2466 memset(&icount
, 0, sizeof(icount
));
2467 if (tty
->ops
->get_icount
)
2468 retval
= tty
->ops
->get_icount(tty
, &icount
);
2471 if (copy_to_user(arg
, &icount
, sizeof(icount
)))
2476 static void tty_warn_deprecated_flags(struct serial_struct __user
*ss
)
2478 static DEFINE_RATELIMIT_STATE(depr_flags
,
2479 DEFAULT_RATELIMIT_INTERVAL
,
2480 DEFAULT_RATELIMIT_BURST
);
2481 char comm
[TASK_COMM_LEN
];
2484 if (get_user(flags
, &ss
->flags
))
2487 flags
&= ASYNC_DEPRECATED
;
2489 if (flags
&& __ratelimit(&depr_flags
))
2490 pr_warn("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2491 __func__
, get_task_comm(comm
, current
), flags
);
2495 * if pty, return the slave side (real_tty)
2496 * otherwise, return self
2498 static struct tty_struct
*tty_pair_get_tty(struct tty_struct
*tty
)
2500 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2501 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
2507 * Split this up, as gcc can choke on it otherwise..
2509 long tty_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
2511 struct tty_struct
*tty
= file_tty(file
);
2512 struct tty_struct
*real_tty
;
2513 void __user
*p
= (void __user
*)arg
;
2515 struct tty_ldisc
*ld
;
2517 if (tty_paranoia_check(tty
, file_inode(file
), "tty_ioctl"))
2520 real_tty
= tty_pair_get_tty(tty
);
2523 * Factor out some common prep work
2531 retval
= tty_check_change(tty
);
2534 if (cmd
!= TIOCCBRK
) {
2535 tty_wait_until_sent(tty
, 0);
2536 if (signal_pending(current
))
2547 return tiocsti(tty
, p
);
2549 return tiocgwinsz(real_tty
, p
);
2551 return tiocswinsz(real_tty
, p
);
2553 return real_tty
!= tty
? -EINVAL
: tioccons(file
);
2555 return fionbio(file
, p
);
2557 set_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2560 clear_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2564 int excl
= test_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2565 return put_user(excl
, (int __user
*)p
);
2568 return tiocgetd(tty
, p
);
2570 return tiocsetd(tty
, p
);
2572 if (!capable(CAP_SYS_ADMIN
))
2578 unsigned int ret
= new_encode_dev(tty_devnum(real_tty
));
2579 return put_user(ret
, (unsigned int __user
*)p
);
2584 case TIOCSBRK
: /* Turn break on, unconditionally */
2585 if (tty
->ops
->break_ctl
)
2586 return tty
->ops
->break_ctl(tty
, -1);
2588 case TIOCCBRK
: /* Turn break off, unconditionally */
2589 if (tty
->ops
->break_ctl
)
2590 return tty
->ops
->break_ctl(tty
, 0);
2592 case TCSBRK
: /* SVID version: non-zero arg --> no break */
2593 /* non-zero arg means wait for all output data
2594 * to be sent (performed above) but don't send break.
2595 * This is used by the tcdrain() termios function.
2598 return send_break(tty
, 250);
2600 case TCSBRKP
: /* support for POSIX tcsendbreak() */
2601 return send_break(tty
, arg
? arg
*100 : 250);
2604 return tty_tiocmget(tty
, p
);
2608 return tty_tiocmset(tty
, cmd
, p
);
2610 retval
= tty_tiocgicount(tty
, p
);
2611 /* For the moment allow fall through to the old method */
2612 if (retval
!= -EINVAL
)
2619 /* flush tty buffer and allow ldisc to process ioctl */
2620 tty_buffer_flush(tty
, NULL
);
2625 tty_warn_deprecated_flags(p
);
2628 /* Special because the struct file is needed */
2629 return ptm_open_peer(file
, tty
, (int)arg
);
2631 retval
= tty_jobctrl_ioctl(tty
, real_tty
, file
, cmd
, arg
);
2632 if (retval
!= -ENOIOCTLCMD
)
2635 if (tty
->ops
->ioctl
) {
2636 retval
= tty
->ops
->ioctl(tty
, cmd
, arg
);
2637 if (retval
!= -ENOIOCTLCMD
)
2640 ld
= tty_ldisc_ref_wait(tty
);
2642 return hung_up_tty_ioctl(file
, cmd
, arg
);
2644 if (ld
->ops
->ioctl
) {
2645 retval
= ld
->ops
->ioctl(tty
, file
, cmd
, arg
);
2646 if (retval
== -ENOIOCTLCMD
)
2649 tty_ldisc_deref(ld
);
2653 #ifdef CONFIG_COMPAT
2654 static long tty_compat_ioctl(struct file
*file
, unsigned int cmd
,
2657 struct tty_struct
*tty
= file_tty(file
);
2658 struct tty_ldisc
*ld
;
2659 int retval
= -ENOIOCTLCMD
;
2661 if (tty_paranoia_check(tty
, file_inode(file
), "tty_ioctl"))
2664 if (tty
->ops
->compat_ioctl
) {
2665 retval
= tty
->ops
->compat_ioctl(tty
, cmd
, arg
);
2666 if (retval
!= -ENOIOCTLCMD
)
2670 ld
= tty_ldisc_ref_wait(tty
);
2672 return hung_up_tty_compat_ioctl(file
, cmd
, arg
);
2673 if (ld
->ops
->compat_ioctl
)
2674 retval
= ld
->ops
->compat_ioctl(tty
, file
, cmd
, arg
);
2676 retval
= n_tty_compat_ioctl_helper(tty
, file
, cmd
, arg
);
2677 tty_ldisc_deref(ld
);
2683 static int this_tty(const void *t
, struct file
*file
, unsigned fd
)
2685 if (likely(file
->f_op
->read
!= tty_read
))
2687 return file_tty(file
) != t
? 0 : fd
+ 1;
2691 * This implements the "Secure Attention Key" --- the idea is to
2692 * prevent trojan horses by killing all processes associated with this
2693 * tty when the user hits the "Secure Attention Key". Required for
2694 * super-paranoid applications --- see the Orange Book for more details.
2696 * This code could be nicer; ideally it should send a HUP, wait a few
2697 * seconds, then send a INT, and then a KILL signal. But you then
2698 * have to coordinate with the init process, since all processes associated
2699 * with the current tty must be dead before the new getty is allowed
2702 * Now, if it would be correct ;-/ The current code has a nasty hole -
2703 * it doesn't catch files in flight. We may send the descriptor to ourselves
2704 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2706 * Nasty bug: do_SAK is being called in interrupt context. This can
2707 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2709 void __do_SAK(struct tty_struct
*tty
)
2714 struct task_struct
*g
, *p
;
2715 struct pid
*session
;
2720 session
= tty
->session
;
2722 tty_ldisc_flush(tty
);
2724 tty_driver_flush_buffer(tty
);
2726 read_lock(&tasklist_lock
);
2727 /* Kill the entire session */
2728 do_each_pid_task(session
, PIDTYPE_SID
, p
) {
2729 tty_notice(tty
, "SAK: killed process %d (%s): by session\n",
2730 task_pid_nr(p
), p
->comm
);
2731 send_sig(SIGKILL
, p
, 1);
2732 } while_each_pid_task(session
, PIDTYPE_SID
, p
);
2734 /* Now kill any processes that happen to have the tty open */
2735 do_each_thread(g
, p
) {
2736 if (p
->signal
->tty
== tty
) {
2737 tty_notice(tty
, "SAK: killed process %d (%s): by controlling tty\n",
2738 task_pid_nr(p
), p
->comm
);
2739 send_sig(SIGKILL
, p
, 1);
2743 i
= iterate_fd(p
->files
, 0, this_tty
, tty
);
2745 tty_notice(tty
, "SAK: killed process %d (%s): by fd#%d\n",
2746 task_pid_nr(p
), p
->comm
, i
- 1);
2747 force_sig(SIGKILL
, p
);
2750 } while_each_thread(g
, p
);
2751 read_unlock(&tasklist_lock
);
2755 static void do_SAK_work(struct work_struct
*work
)
2757 struct tty_struct
*tty
=
2758 container_of(work
, struct tty_struct
, SAK_work
);
2763 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2764 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2765 * the values which we write to it will be identical to the values which it
2766 * already has. --akpm
2768 void do_SAK(struct tty_struct
*tty
)
2772 schedule_work(&tty
->SAK_work
);
2775 EXPORT_SYMBOL(do_SAK
);
2777 static int dev_match_devt(struct device
*dev
, const void *data
)
2779 const dev_t
*devt
= data
;
2780 return dev
->devt
== *devt
;
2783 /* Must put_device() after it's unused! */
2784 static struct device
*tty_get_device(struct tty_struct
*tty
)
2786 dev_t devt
= tty_devnum(tty
);
2787 return class_find_device(tty_class
, NULL
, &devt
, dev_match_devt
);
2794 * This subroutine allocates and initializes a tty structure.
2796 * Locking: none - tty in question is not exposed at this point
2799 struct tty_struct
*alloc_tty_struct(struct tty_driver
*driver
, int idx
)
2801 struct tty_struct
*tty
;
2803 tty
= kzalloc(sizeof(*tty
), GFP_KERNEL
);
2807 kref_init(&tty
->kref
);
2808 tty
->magic
= TTY_MAGIC
;
2809 tty_ldisc_init(tty
);
2810 tty
->session
= NULL
;
2812 mutex_init(&tty
->legacy_mutex
);
2813 mutex_init(&tty
->throttle_mutex
);
2814 init_rwsem(&tty
->termios_rwsem
);
2815 mutex_init(&tty
->winsize_mutex
);
2816 init_ldsem(&tty
->ldisc_sem
);
2817 init_waitqueue_head(&tty
->write_wait
);
2818 init_waitqueue_head(&tty
->read_wait
);
2819 INIT_WORK(&tty
->hangup_work
, do_tty_hangup
);
2820 mutex_init(&tty
->atomic_write_lock
);
2821 spin_lock_init(&tty
->ctrl_lock
);
2822 spin_lock_init(&tty
->flow_lock
);
2823 spin_lock_init(&tty
->files_lock
);
2824 INIT_LIST_HEAD(&tty
->tty_files
);
2825 INIT_WORK(&tty
->SAK_work
, do_SAK_work
);
2827 tty
->driver
= driver
;
2828 tty
->ops
= driver
->ops
;
2830 tty_line_name(driver
, idx
, tty
->name
);
2831 tty
->dev
= tty_get_device(tty
);
2837 * tty_put_char - write one character to a tty
2841 * Write one byte to the tty using the provided put_char method
2842 * if present. Returns the number of characters successfully output.
2844 * Note: the specific put_char operation in the driver layer may go
2845 * away soon. Don't call it directly, use this method
2848 int tty_put_char(struct tty_struct
*tty
, unsigned char ch
)
2850 if (tty
->ops
->put_char
)
2851 return tty
->ops
->put_char(tty
, ch
);
2852 return tty
->ops
->write(tty
, &ch
, 1);
2854 EXPORT_SYMBOL_GPL(tty_put_char
);
2856 struct class *tty_class
;
2858 static int tty_cdev_add(struct tty_driver
*driver
, dev_t dev
,
2859 unsigned int index
, unsigned int count
)
2863 /* init here, since reused cdevs cause crashes */
2864 driver
->cdevs
[index
] = cdev_alloc();
2865 if (!driver
->cdevs
[index
])
2867 driver
->cdevs
[index
]->ops
= &tty_fops
;
2868 driver
->cdevs
[index
]->owner
= driver
->owner
;
2869 err
= cdev_add(driver
->cdevs
[index
], dev
, count
);
2871 kobject_put(&driver
->cdevs
[index
]->kobj
);
2876 * tty_register_device - register a tty device
2877 * @driver: the tty driver that describes the tty device
2878 * @index: the index in the tty driver for this tty device
2879 * @device: a struct device that is associated with this tty device.
2880 * This field is optional, if there is no known struct device
2881 * for this tty device it can be set to NULL safely.
2883 * Returns a pointer to the struct device for this tty device
2884 * (or ERR_PTR(-EFOO) on error).
2886 * This call is required to be made to register an individual tty device
2887 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2888 * that bit is not set, this function should not be called by a tty
2894 struct device
*tty_register_device(struct tty_driver
*driver
, unsigned index
,
2895 struct device
*device
)
2897 return tty_register_device_attr(driver
, index
, device
, NULL
, NULL
);
2899 EXPORT_SYMBOL(tty_register_device
);
2901 static void tty_device_create_release(struct device
*dev
)
2903 dev_dbg(dev
, "releasing...\n");
2908 * tty_register_device_attr - register a tty device
2909 * @driver: the tty driver that describes the tty device
2910 * @index: the index in the tty driver for this tty device
2911 * @device: a struct device that is associated with this tty device.
2912 * This field is optional, if there is no known struct device
2913 * for this tty device it can be set to NULL safely.
2914 * @drvdata: Driver data to be set to device.
2915 * @attr_grp: Attribute group to be set on device.
2917 * Returns a pointer to the struct device for this tty device
2918 * (or ERR_PTR(-EFOO) on error).
2920 * This call is required to be made to register an individual tty device
2921 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2922 * that bit is not set, this function should not be called by a tty
2927 struct device
*tty_register_device_attr(struct tty_driver
*driver
,
2928 unsigned index
, struct device
*device
,
2930 const struct attribute_group
**attr_grp
)
2933 dev_t devt
= MKDEV(driver
->major
, driver
->minor_start
) + index
;
2934 struct ktermios
*tp
;
2938 if (index
>= driver
->num
) {
2939 pr_err("%s: Attempt to register invalid tty line number (%d)\n",
2940 driver
->name
, index
);
2941 return ERR_PTR(-EINVAL
);
2944 if (driver
->type
== TTY_DRIVER_TYPE_PTY
)
2945 pty_line_name(driver
, index
, name
);
2947 tty_line_name(driver
, index
, name
);
2949 dev
= kzalloc(sizeof(*dev
), GFP_KERNEL
);
2951 return ERR_PTR(-ENOMEM
);
2954 dev
->class = tty_class
;
2955 dev
->parent
= device
;
2956 dev
->release
= tty_device_create_release
;
2957 dev_set_name(dev
, "%s", name
);
2958 dev
->groups
= attr_grp
;
2959 dev_set_drvdata(dev
, drvdata
);
2961 dev_set_uevent_suppress(dev
, 1);
2963 retval
= device_register(dev
);
2967 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
)) {
2969 * Free any saved termios data so that the termios state is
2970 * reset when reusing a minor number.
2972 tp
= driver
->termios
[index
];
2974 driver
->termios
[index
] = NULL
;
2978 retval
= tty_cdev_add(driver
, devt
, index
, 1);
2983 dev_set_uevent_suppress(dev
, 0);
2984 kobject_uevent(&dev
->kobj
, KOBJ_ADD
);
2993 return ERR_PTR(retval
);
2995 EXPORT_SYMBOL_GPL(tty_register_device_attr
);
2998 * tty_unregister_device - unregister a tty device
2999 * @driver: the tty driver that describes the tty device
3000 * @index: the index in the tty driver for this tty device
3002 * If a tty device is registered with a call to tty_register_device() then
3003 * this function must be called when the tty device is gone.
3008 void tty_unregister_device(struct tty_driver
*driver
, unsigned index
)
3010 device_destroy(tty_class
,
3011 MKDEV(driver
->major
, driver
->minor_start
) + index
);
3012 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
)) {
3013 cdev_del(driver
->cdevs
[index
]);
3014 driver
->cdevs
[index
] = NULL
;
3017 EXPORT_SYMBOL(tty_unregister_device
);
3020 * __tty_alloc_driver -- allocate tty driver
3021 * @lines: count of lines this driver can handle at most
3022 * @owner: module which is responsible for this driver
3023 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3025 * This should not be called directly, some of the provided macros should be
3026 * used instead. Use IS_ERR and friends on @retval.
3028 struct tty_driver
*__tty_alloc_driver(unsigned int lines
, struct module
*owner
,
3029 unsigned long flags
)
3031 struct tty_driver
*driver
;
3032 unsigned int cdevs
= 1;
3035 if (!lines
|| (flags
& TTY_DRIVER_UNNUMBERED_NODE
&& lines
> 1))
3036 return ERR_PTR(-EINVAL
);
3038 driver
= kzalloc(sizeof(struct tty_driver
), GFP_KERNEL
);
3040 return ERR_PTR(-ENOMEM
);
3042 kref_init(&driver
->kref
);
3043 driver
->magic
= TTY_DRIVER_MAGIC
;
3044 driver
->num
= lines
;
3045 driver
->owner
= owner
;
3046 driver
->flags
= flags
;
3048 if (!(flags
& TTY_DRIVER_DEVPTS_MEM
)) {
3049 driver
->ttys
= kcalloc(lines
, sizeof(*driver
->ttys
),
3051 driver
->termios
= kcalloc(lines
, sizeof(*driver
->termios
),
3053 if (!driver
->ttys
|| !driver
->termios
) {
3059 if (!(flags
& TTY_DRIVER_DYNAMIC_ALLOC
)) {
3060 driver
->ports
= kcalloc(lines
, sizeof(*driver
->ports
),
3062 if (!driver
->ports
) {
3069 driver
->cdevs
= kcalloc(cdevs
, sizeof(*driver
->cdevs
), GFP_KERNEL
);
3070 if (!driver
->cdevs
) {
3077 kfree(driver
->ports
);
3078 kfree(driver
->ttys
);
3079 kfree(driver
->termios
);
3080 kfree(driver
->cdevs
);
3082 return ERR_PTR(err
);
3084 EXPORT_SYMBOL(__tty_alloc_driver
);
3086 static void destruct_tty_driver(struct kref
*kref
)
3088 struct tty_driver
*driver
= container_of(kref
, struct tty_driver
, kref
);
3090 struct ktermios
*tp
;
3092 if (driver
->flags
& TTY_DRIVER_INSTALLED
) {
3093 for (i
= 0; i
< driver
->num
; i
++) {
3094 tp
= driver
->termios
[i
];
3096 driver
->termios
[i
] = NULL
;
3099 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
))
3100 tty_unregister_device(driver
, i
);
3102 proc_tty_unregister_driver(driver
);
3103 if (driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
)
3104 cdev_del(driver
->cdevs
[0]);
3106 kfree(driver
->cdevs
);
3107 kfree(driver
->ports
);
3108 kfree(driver
->termios
);
3109 kfree(driver
->ttys
);
3113 void tty_driver_kref_put(struct tty_driver
*driver
)
3115 kref_put(&driver
->kref
, destruct_tty_driver
);
3117 EXPORT_SYMBOL(tty_driver_kref_put
);
3119 void tty_set_operations(struct tty_driver
*driver
,
3120 const struct tty_operations
*op
)
3124 EXPORT_SYMBOL(tty_set_operations
);
3126 void put_tty_driver(struct tty_driver
*d
)
3128 tty_driver_kref_put(d
);
3130 EXPORT_SYMBOL(put_tty_driver
);
3133 * Called by a tty driver to register itself.
3135 int tty_register_driver(struct tty_driver
*driver
)
3142 if (!driver
->major
) {
3143 error
= alloc_chrdev_region(&dev
, driver
->minor_start
,
3144 driver
->num
, driver
->name
);
3146 driver
->major
= MAJOR(dev
);
3147 driver
->minor_start
= MINOR(dev
);
3150 dev
= MKDEV(driver
->major
, driver
->minor_start
);
3151 error
= register_chrdev_region(dev
, driver
->num
, driver
->name
);
3156 if (driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
) {
3157 error
= tty_cdev_add(driver
, dev
, 0, driver
->num
);
3159 goto err_unreg_char
;
3162 mutex_lock(&tty_mutex
);
3163 list_add(&driver
->tty_drivers
, &tty_drivers
);
3164 mutex_unlock(&tty_mutex
);
3166 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
)) {
3167 for (i
= 0; i
< driver
->num
; i
++) {
3168 d
= tty_register_device(driver
, i
, NULL
);
3171 goto err_unreg_devs
;
3175 proc_tty_register_driver(driver
);
3176 driver
->flags
|= TTY_DRIVER_INSTALLED
;
3180 for (i
--; i
>= 0; i
--)
3181 tty_unregister_device(driver
, i
);
3183 mutex_lock(&tty_mutex
);
3184 list_del(&driver
->tty_drivers
);
3185 mutex_unlock(&tty_mutex
);
3188 unregister_chrdev_region(dev
, driver
->num
);
3192 EXPORT_SYMBOL(tty_register_driver
);
3195 * Called by a tty driver to unregister itself.
3197 int tty_unregister_driver(struct tty_driver
*driver
)
3201 if (driver
->refcount
)
3204 unregister_chrdev_region(MKDEV(driver
->major
, driver
->minor_start
),
3206 mutex_lock(&tty_mutex
);
3207 list_del(&driver
->tty_drivers
);
3208 mutex_unlock(&tty_mutex
);
3212 EXPORT_SYMBOL(tty_unregister_driver
);
3214 dev_t
tty_devnum(struct tty_struct
*tty
)
3216 return MKDEV(tty
->driver
->major
, tty
->driver
->minor_start
) + tty
->index
;
3218 EXPORT_SYMBOL(tty_devnum
);
3220 void tty_default_fops(struct file_operations
*fops
)
3225 static char *tty_devnode(struct device
*dev
, umode_t
*mode
)
3229 if (dev
->devt
== MKDEV(TTYAUX_MAJOR
, 0) ||
3230 dev
->devt
== MKDEV(TTYAUX_MAJOR
, 2))
3235 static int __init
tty_class_init(void)
3237 tty_class
= class_create(THIS_MODULE
, "tty");
3238 if (IS_ERR(tty_class
))
3239 return PTR_ERR(tty_class
);
3240 tty_class
->devnode
= tty_devnode
;
3244 postcore_initcall(tty_class_init
);
3246 /* 3/2004 jmc: why do these devices exist? */
3247 static struct cdev tty_cdev
, console_cdev
;
3249 static ssize_t
show_cons_active(struct device
*dev
,
3250 struct device_attribute
*attr
, char *buf
)
3252 struct console
*cs
[16];
3258 for_each_console(c
) {
3263 if ((c
->flags
& CON_ENABLED
) == 0)
3266 if (i
>= ARRAY_SIZE(cs
))
3270 int index
= cs
[i
]->index
;
3271 struct tty_driver
*drv
= cs
[i
]->device(cs
[i
], &index
);
3273 /* don't resolve tty0 as some programs depend on it */
3274 if (drv
&& (cs
[i
]->index
> 0 || drv
->major
!= TTY_MAJOR
))
3275 count
+= tty_line_name(drv
, index
, buf
+ count
);
3277 count
+= sprintf(buf
+ count
, "%s%d",
3278 cs
[i
]->name
, cs
[i
]->index
);
3280 count
+= sprintf(buf
+ count
, "%c", i
? ' ':'\n');
3286 static DEVICE_ATTR(active
, S_IRUGO
, show_cons_active
, NULL
);
3288 static struct attribute
*cons_dev_attrs
[] = {
3289 &dev_attr_active
.attr
,
3293 ATTRIBUTE_GROUPS(cons_dev
);
3295 static struct device
*consdev
;
3297 void console_sysfs_notify(void)
3300 sysfs_notify(&consdev
->kobj
, NULL
, "active");
3304 * Ok, now we can initialize the rest of the tty devices and can count
3305 * on memory allocations, interrupts etc..
3307 int __init
tty_init(void)
3309 cdev_init(&tty_cdev
, &tty_fops
);
3310 if (cdev_add(&tty_cdev
, MKDEV(TTYAUX_MAJOR
, 0), 1) ||
3311 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 0), 1, "/dev/tty") < 0)
3312 panic("Couldn't register /dev/tty driver\n");
3313 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 0), NULL
, "tty");
3315 cdev_init(&console_cdev
, &console_fops
);
3316 if (cdev_add(&console_cdev
, MKDEV(TTYAUX_MAJOR
, 1), 1) ||
3317 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 1), 1, "/dev/console") < 0)
3318 panic("Couldn't register /dev/console driver\n");
3319 consdev
= device_create_with_groups(tty_class
, NULL
,
3320 MKDEV(TTYAUX_MAJOR
, 1), NULL
,
3321 cons_dev_groups
, "console");
3322 if (IS_ERR(consdev
))
3326 vty_init(&console_fops
);