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 tty
->port
->itty
= tty
;
1328 * Structures all installed ... call the ldisc open routines.
1329 * If we fail here just call release_tty to clean up. No need
1330 * to decrement the use counts, as release_tty doesn't care.
1332 retval
= tty_ldisc_setup(tty
, tty
->link
);
1334 goto err_release_tty
;
1335 /* Return the tty locked so that it cannot vanish under the caller */
1340 free_tty_struct(tty
);
1342 module_put(driver
->owner
);
1343 return ERR_PTR(retval
);
1345 /* call the tty release_tty routine to clean out this slot */
1348 tty_info_ratelimited(tty
, "ldisc open failed (%d), clearing slot %d\n",
1350 release_tty(tty
, idx
);
1351 return ERR_PTR(retval
);
1354 static void tty_free_termios(struct tty_struct
*tty
)
1356 struct ktermios
*tp
;
1357 int idx
= tty
->index
;
1359 /* If the port is going to reset then it has no termios to save */
1360 if (tty
->driver
->flags
& TTY_DRIVER_RESET_TERMIOS
)
1363 /* Stash the termios data */
1364 tp
= tty
->driver
->termios
[idx
];
1366 tp
= kmalloc(sizeof(struct ktermios
), GFP_KERNEL
);
1369 tty
->driver
->termios
[idx
] = tp
;
1375 * tty_flush_works - flush all works of a tty/pty pair
1376 * @tty: tty device to flush works for (or either end of a pty pair)
1378 * Sync flush all works belonging to @tty (and the 'other' tty).
1380 static void tty_flush_works(struct tty_struct
*tty
)
1382 flush_work(&tty
->SAK_work
);
1383 flush_work(&tty
->hangup_work
);
1385 flush_work(&tty
->link
->SAK_work
);
1386 flush_work(&tty
->link
->hangup_work
);
1391 * release_one_tty - release tty structure memory
1392 * @kref: kref of tty we are obliterating
1394 * Releases memory associated with a tty structure, and clears out the
1395 * driver table slots. This function is called when a device is no longer
1396 * in use. It also gets called when setup of a device fails.
1399 * takes the file list lock internally when working on the list
1400 * of ttys that the driver keeps.
1402 * This method gets called from a work queue so that the driver private
1403 * cleanup ops can sleep (needed for USB at least)
1405 static void release_one_tty(struct work_struct
*work
)
1407 struct tty_struct
*tty
=
1408 container_of(work
, struct tty_struct
, hangup_work
);
1409 struct tty_driver
*driver
= tty
->driver
;
1410 struct module
*owner
= driver
->owner
;
1412 if (tty
->ops
->cleanup
)
1413 tty
->ops
->cleanup(tty
);
1416 tty_driver_kref_put(driver
);
1419 spin_lock(&tty
->files_lock
);
1420 list_del_init(&tty
->tty_files
);
1421 spin_unlock(&tty
->files_lock
);
1424 put_pid(tty
->session
);
1425 free_tty_struct(tty
);
1428 static void queue_release_one_tty(struct kref
*kref
)
1430 struct tty_struct
*tty
= container_of(kref
, struct tty_struct
, kref
);
1432 /* The hangup queue is now free so we can reuse it rather than
1433 waste a chunk of memory for each port */
1434 INIT_WORK(&tty
->hangup_work
, release_one_tty
);
1435 schedule_work(&tty
->hangup_work
);
1439 * tty_kref_put - release a tty kref
1442 * Release a reference to a tty device and if need be let the kref
1443 * layer destruct the object for us
1446 void tty_kref_put(struct tty_struct
*tty
)
1449 kref_put(&tty
->kref
, queue_release_one_tty
);
1451 EXPORT_SYMBOL(tty_kref_put
);
1454 * release_tty - release tty structure memory
1456 * Release both @tty and a possible linked partner (think pty pair),
1457 * and decrement the refcount of the backing module.
1461 * takes the file list lock internally when working on the list
1462 * of ttys that the driver keeps.
1465 static void release_tty(struct tty_struct
*tty
, int idx
)
1467 /* This should always be true but check for the moment */
1468 WARN_ON(tty
->index
!= idx
);
1469 WARN_ON(!mutex_is_locked(&tty_mutex
));
1470 if (tty
->ops
->shutdown
)
1471 tty
->ops
->shutdown(tty
);
1472 tty_free_termios(tty
);
1473 tty_driver_remove_tty(tty
->driver
, tty
);
1474 tty
->port
->itty
= NULL
;
1476 tty
->link
->port
->itty
= NULL
;
1477 tty_buffer_cancel_work(tty
->port
);
1479 tty_kref_put(tty
->link
);
1484 * tty_release_checks - check a tty before real release
1485 * @tty: tty to check
1486 * @o_tty: link of @tty (if any)
1487 * @idx: index of the tty
1489 * Performs some paranoid checking before true release of the @tty.
1490 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1492 static int tty_release_checks(struct tty_struct
*tty
, int idx
)
1494 #ifdef TTY_PARANOIA_CHECK
1495 if (idx
< 0 || idx
>= tty
->driver
->num
) {
1496 tty_debug(tty
, "bad idx %d\n", idx
);
1500 /* not much to check for devpts */
1501 if (tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
)
1504 if (tty
!= tty
->driver
->ttys
[idx
]) {
1505 tty_debug(tty
, "bad driver table[%d] = %p\n",
1506 idx
, tty
->driver
->ttys
[idx
]);
1509 if (tty
->driver
->other
) {
1510 struct tty_struct
*o_tty
= tty
->link
;
1512 if (o_tty
!= tty
->driver
->other
->ttys
[idx
]) {
1513 tty_debug(tty
, "bad other table[%d] = %p\n",
1514 idx
, tty
->driver
->other
->ttys
[idx
]);
1517 if (o_tty
->link
!= tty
) {
1518 tty_debug(tty
, "bad link = %p\n", o_tty
->link
);
1527 * tty_kclose - closes tty opened by tty_kopen
1530 * Performs the final steps to release and free a tty device. It is the
1531 * same as tty_release_struct except that it also resets TTY_PORT_KOPENED
1532 * flag on tty->port.
1534 void tty_kclose(struct tty_struct
*tty
)
1537 * Ask the line discipline code to release its structures
1539 tty_ldisc_release(tty
);
1541 /* Wait for pending work before tty destruction commmences */
1542 tty_flush_works(tty
);
1544 tty_debug_hangup(tty
, "freeing structure\n");
1546 * The release_tty function takes care of the details of clearing
1547 * the slots and preserving the termios structure. The tty_unlock_pair
1548 * should be safe as we keep a kref while the tty is locked (so the
1549 * unlock never unlocks a freed tty).
1551 mutex_lock(&tty_mutex
);
1552 tty_port_set_kopened(tty
->port
, 0);
1553 release_tty(tty
, tty
->index
);
1554 mutex_unlock(&tty_mutex
);
1556 EXPORT_SYMBOL_GPL(tty_kclose
);
1559 * tty_release_struct - release a tty struct
1561 * @idx: index of the tty
1563 * Performs the final steps to release and free a tty device. It is
1564 * roughly the reverse of tty_init_dev.
1566 void tty_release_struct(struct tty_struct
*tty
, int idx
)
1569 * Ask the line discipline code to release its structures
1571 tty_ldisc_release(tty
);
1573 /* Wait for pending work before tty destruction commmences */
1574 tty_flush_works(tty
);
1576 tty_debug_hangup(tty
, "freeing structure\n");
1578 * The release_tty function takes care of the details of clearing
1579 * the slots and preserving the termios structure. The tty_unlock_pair
1580 * should be safe as we keep a kref while the tty is locked (so the
1581 * unlock never unlocks a freed tty).
1583 mutex_lock(&tty_mutex
);
1584 release_tty(tty
, idx
);
1585 mutex_unlock(&tty_mutex
);
1587 EXPORT_SYMBOL_GPL(tty_release_struct
);
1590 * tty_release - vfs callback for close
1591 * @inode: inode of tty
1592 * @filp: file pointer for handle to tty
1594 * Called the last time each file handle is closed that references
1595 * this tty. There may however be several such references.
1598 * Takes bkl. See tty_release_dev
1600 * Even releasing the tty structures is a tricky business.. We have
1601 * to be very careful that the structures are all released at the
1602 * same time, as interrupts might otherwise get the wrong pointers.
1604 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1605 * lead to double frees or releasing memory still in use.
1608 int tty_release(struct inode
*inode
, struct file
*filp
)
1610 struct tty_struct
*tty
= file_tty(filp
);
1611 struct tty_struct
*o_tty
= NULL
;
1612 int do_sleep
, final
;
1617 if (tty_paranoia_check(tty
, inode
, __func__
))
1621 check_tty_count(tty
, __func__
);
1623 __tty_fasync(-1, filp
, 0);
1626 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1627 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
1630 if (tty_release_checks(tty
, idx
)) {
1635 tty_debug_hangup(tty
, "releasing (count=%d)\n", tty
->count
);
1637 if (tty
->ops
->close
)
1638 tty
->ops
->close(tty
, filp
);
1640 /* If tty is pty master, lock the slave pty (stable lock order) */
1641 tty_lock_slave(o_tty
);
1644 * Sanity check: if tty->count is going to zero, there shouldn't be
1645 * any waiters on tty->read_wait or tty->write_wait. We test the
1646 * wait queues and kick everyone out _before_ actually starting to
1647 * close. This ensures that we won't block while releasing the tty
1650 * The test for the o_tty closing is necessary, since the master and
1651 * slave sides may close in any order. If the slave side closes out
1652 * first, its count will be one, since the master side holds an open.
1653 * Thus this test wouldn't be triggered at the time the slave closed,
1659 if (tty
->count
<= 1) {
1660 if (waitqueue_active(&tty
->read_wait
)) {
1661 wake_up_poll(&tty
->read_wait
, POLLIN
);
1664 if (waitqueue_active(&tty
->write_wait
)) {
1665 wake_up_poll(&tty
->write_wait
, POLLOUT
);
1669 if (o_tty
&& o_tty
->count
<= 1) {
1670 if (waitqueue_active(&o_tty
->read_wait
)) {
1671 wake_up_poll(&o_tty
->read_wait
, POLLIN
);
1674 if (waitqueue_active(&o_tty
->write_wait
)) {
1675 wake_up_poll(&o_tty
->write_wait
, POLLOUT
);
1684 tty_warn(tty
, "read/write wait queue active!\n");
1686 schedule_timeout_killable(timeout
);
1687 if (timeout
< 120 * HZ
)
1688 timeout
= 2 * timeout
+ 1;
1690 timeout
= MAX_SCHEDULE_TIMEOUT
;
1694 if (--o_tty
->count
< 0) {
1695 tty_warn(tty
, "bad slave count (%d)\n", o_tty
->count
);
1699 if (--tty
->count
< 0) {
1700 tty_warn(tty
, "bad tty->count (%d)\n", tty
->count
);
1705 * We've decremented tty->count, so we need to remove this file
1706 * descriptor off the tty->tty_files list; this serves two
1708 * - check_tty_count sees the correct number of file descriptors
1709 * associated with this tty.
1710 * - do_tty_hangup no longer sees this file descriptor as
1711 * something that needs to be handled for hangups.
1716 * Perform some housekeeping before deciding whether to return.
1718 * If _either_ side is closing, make sure there aren't any
1719 * processes that still think tty or o_tty is their controlling
1723 read_lock(&tasklist_lock
);
1724 session_clear_tty(tty
->session
);
1726 session_clear_tty(o_tty
->session
);
1727 read_unlock(&tasklist_lock
);
1730 /* check whether both sides are closing ... */
1731 final
= !tty
->count
&& !(o_tty
&& o_tty
->count
);
1733 tty_unlock_slave(o_tty
);
1736 /* At this point, the tty->count == 0 should ensure a dead tty
1737 cannot be re-opened by a racing opener */
1742 tty_debug_hangup(tty
, "final close\n");
1744 tty_release_struct(tty
, idx
);
1749 * tty_open_current_tty - get locked tty of current task
1750 * @device: device number
1751 * @filp: file pointer to tty
1752 * @return: locked tty of the current task iff @device is /dev/tty
1754 * Performs a re-open of the current task's controlling tty.
1756 * We cannot return driver and index like for the other nodes because
1757 * devpts will not work then. It expects inodes to be from devpts FS.
1759 static struct tty_struct
*tty_open_current_tty(dev_t device
, struct file
*filp
)
1761 struct tty_struct
*tty
;
1764 if (device
!= MKDEV(TTYAUX_MAJOR
, 0))
1767 tty
= get_current_tty();
1769 return ERR_PTR(-ENXIO
);
1771 filp
->f_flags
|= O_NONBLOCK
; /* Don't let /dev/tty block */
1774 tty_kref_put(tty
); /* safe to drop the kref now */
1776 retval
= tty_reopen(tty
);
1779 tty
= ERR_PTR(retval
);
1785 * tty_lookup_driver - lookup a tty driver for a given device file
1786 * @device: device number
1787 * @filp: file pointer to tty
1788 * @index: index for the device in the @return driver
1789 * @return: driver for this inode (with increased refcount)
1791 * If @return is not erroneous, the caller is responsible to decrement the
1792 * refcount by tty_driver_kref_put.
1794 * Locking: tty_mutex protects get_tty_driver
1796 static struct tty_driver
*tty_lookup_driver(dev_t device
, struct file
*filp
,
1799 struct tty_driver
*driver
;
1803 case MKDEV(TTY_MAJOR
, 0): {
1804 extern struct tty_driver
*console_driver
;
1805 driver
= tty_driver_kref_get(console_driver
);
1806 *index
= fg_console
;
1810 case MKDEV(TTYAUX_MAJOR
, 1): {
1811 struct tty_driver
*console_driver
= console_device(index
);
1812 if (console_driver
) {
1813 driver
= tty_driver_kref_get(console_driver
);
1814 if (driver
&& filp
) {
1815 /* Don't let /dev/console block */
1816 filp
->f_flags
|= O_NONBLOCK
;
1820 return ERR_PTR(-ENODEV
);
1823 driver
= get_tty_driver(device
, index
);
1825 return ERR_PTR(-ENODEV
);
1832 * tty_kopen - open a tty device for kernel
1833 * @device: dev_t of device to open
1835 * Opens tty exclusively for kernel. Performs the driver lookup,
1836 * makes sure it's not already opened and performs the first-time
1837 * tty initialization.
1839 * Returns the locked initialized &tty_struct
1841 * Claims the global tty_mutex to serialize:
1842 * - concurrent first-time tty initialization
1843 * - concurrent tty driver removal w/ lookup
1844 * - concurrent tty removal from driver table
1846 struct tty_struct
*tty_kopen(dev_t device
)
1848 struct tty_struct
*tty
;
1849 struct tty_driver
*driver
= NULL
;
1852 mutex_lock(&tty_mutex
);
1853 driver
= tty_lookup_driver(device
, NULL
, &index
);
1854 if (IS_ERR(driver
)) {
1855 mutex_unlock(&tty_mutex
);
1856 return ERR_CAST(driver
);
1859 /* check whether we're reopening an existing tty */
1860 tty
= tty_driver_lookup_tty(driver
, NULL
, index
);
1865 /* drop kref from tty_driver_lookup_tty() */
1867 tty
= ERR_PTR(-EBUSY
);
1868 } else { /* tty_init_dev returns tty with the tty_lock held */
1869 tty
= tty_init_dev(driver
, index
);
1872 tty_port_set_kopened(tty
->port
, 1);
1875 mutex_unlock(&tty_mutex
);
1876 tty_driver_kref_put(driver
);
1879 EXPORT_SYMBOL_GPL(tty_kopen
);
1882 * tty_open_by_driver - open a tty device
1883 * @device: dev_t of device to open
1884 * @inode: inode of device file
1885 * @filp: file pointer to tty
1887 * Performs the driver lookup, checks for a reopen, or otherwise
1888 * performs the first-time tty initialization.
1890 * Returns the locked initialized or re-opened &tty_struct
1892 * Claims the global tty_mutex to serialize:
1893 * - concurrent first-time tty initialization
1894 * - concurrent tty driver removal w/ lookup
1895 * - concurrent tty removal from driver table
1897 static struct tty_struct
*tty_open_by_driver(dev_t device
, struct inode
*inode
,
1900 struct tty_struct
*tty
;
1901 struct tty_driver
*driver
= NULL
;
1905 mutex_lock(&tty_mutex
);
1906 driver
= tty_lookup_driver(device
, filp
, &index
);
1907 if (IS_ERR(driver
)) {
1908 mutex_unlock(&tty_mutex
);
1909 return ERR_CAST(driver
);
1912 /* check whether we're reopening an existing tty */
1913 tty
= tty_driver_lookup_tty(driver
, filp
, index
);
1915 mutex_unlock(&tty_mutex
);
1920 if (tty_port_kopened(tty
->port
)) {
1922 mutex_unlock(&tty_mutex
);
1923 tty
= ERR_PTR(-EBUSY
);
1926 mutex_unlock(&tty_mutex
);
1927 retval
= tty_lock_interruptible(tty
);
1928 tty_kref_put(tty
); /* drop kref from tty_driver_lookup_tty() */
1930 if (retval
== -EINTR
)
1931 retval
= -ERESTARTSYS
;
1932 tty
= ERR_PTR(retval
);
1935 retval
= tty_reopen(tty
);
1938 tty
= ERR_PTR(retval
);
1940 } else { /* Returns with the tty_lock held for now */
1941 tty
= tty_init_dev(driver
, index
);
1942 mutex_unlock(&tty_mutex
);
1945 tty_driver_kref_put(driver
);
1950 * tty_open - open a tty device
1951 * @inode: inode of device file
1952 * @filp: file pointer to tty
1954 * tty_open and tty_release keep up the tty count that contains the
1955 * number of opens done on a tty. We cannot use the inode-count, as
1956 * different inodes might point to the same tty.
1958 * Open-counting is needed for pty masters, as well as for keeping
1959 * track of serial lines: DTR is dropped when the last close happens.
1960 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1962 * The termios state of a pty is reset on first open so that
1963 * settings don't persist across reuse.
1965 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
1966 * tty->count should protect the rest.
1967 * ->siglock protects ->signal/->sighand
1969 * Note: the tty_unlock/lock cases without a ref are only safe due to
1973 static int tty_open(struct inode
*inode
, struct file
*filp
)
1975 struct tty_struct
*tty
;
1977 dev_t device
= inode
->i_rdev
;
1978 unsigned saved_flags
= filp
->f_flags
;
1980 nonseekable_open(inode
, filp
);
1983 retval
= tty_alloc_file(filp
);
1987 tty
= tty_open_current_tty(device
, filp
);
1989 tty
= tty_open_by_driver(device
, inode
, filp
);
1992 tty_free_file(filp
);
1993 retval
= PTR_ERR(tty
);
1994 if (retval
!= -EAGAIN
|| signal_pending(current
))
2000 tty_add_file(tty
, filp
);
2002 check_tty_count(tty
, __func__
);
2003 tty_debug_hangup(tty
, "opening (count=%d)\n", tty
->count
);
2006 retval
= tty
->ops
->open(tty
, filp
);
2009 filp
->f_flags
= saved_flags
;
2012 tty_debug_hangup(tty
, "open error %d, releasing\n", retval
);
2014 tty_unlock(tty
); /* need to call tty_release without BTM */
2015 tty_release(inode
, filp
);
2016 if (retval
!= -ERESTARTSYS
)
2019 if (signal_pending(current
))
2024 * Need to reset f_op in case a hangup happened.
2026 if (tty_hung_up_p(filp
))
2027 filp
->f_op
= &tty_fops
;
2030 clear_bit(TTY_HUPPED
, &tty
->flags
);
2032 noctty
= (filp
->f_flags
& O_NOCTTY
) ||
2033 (IS_ENABLED(CONFIG_VT
) && device
== MKDEV(TTY_MAJOR
, 0)) ||
2034 device
== MKDEV(TTYAUX_MAJOR
, 1) ||
2035 (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2036 tty
->driver
->subtype
== PTY_TYPE_MASTER
);
2038 tty_open_proc_set_tty(filp
, tty
);
2046 * tty_poll - check tty status
2047 * @filp: file being polled
2048 * @wait: poll wait structures to update
2050 * Call the line discipline polling method to obtain the poll
2051 * status of the device.
2053 * Locking: locks called line discipline but ldisc poll method
2054 * may be re-entered freely by other callers.
2057 static unsigned int tty_poll(struct file
*filp
, poll_table
*wait
)
2059 struct tty_struct
*tty
= file_tty(filp
);
2060 struct tty_ldisc
*ld
;
2063 if (tty_paranoia_check(tty
, file_inode(filp
), "tty_poll"))
2066 ld
= tty_ldisc_ref_wait(tty
);
2068 return hung_up_tty_poll(filp
, wait
);
2070 ret
= ld
->ops
->poll(tty
, filp
, wait
);
2071 tty_ldisc_deref(ld
);
2075 static int __tty_fasync(int fd
, struct file
*filp
, int on
)
2077 struct tty_struct
*tty
= file_tty(filp
);
2078 unsigned long flags
;
2081 if (tty_paranoia_check(tty
, file_inode(filp
), "tty_fasync"))
2084 retval
= fasync_helper(fd
, filp
, on
, &tty
->fasync
);
2092 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2095 type
= PIDTYPE_PGID
;
2097 pid
= task_pid(current
);
2101 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2102 __f_setown(filp
, pid
, type
, 0);
2110 static int tty_fasync(int fd
, struct file
*filp
, int on
)
2112 struct tty_struct
*tty
= file_tty(filp
);
2113 int retval
= -ENOTTY
;
2116 if (!tty_hung_up_p(filp
))
2117 retval
= __tty_fasync(fd
, filp
, on
);
2124 * tiocsti - fake input character
2125 * @tty: tty to fake input into
2126 * @p: pointer to character
2128 * Fake input to a tty device. Does the necessary locking and
2131 * FIXME: does not honour flow control ??
2134 * Called functions take tty_ldiscs_lock
2135 * current->signal->tty check is safe without locks
2137 * FIXME: may race normal receive processing
2140 static int tiocsti(struct tty_struct
*tty
, char __user
*p
)
2143 struct tty_ldisc
*ld
;
2145 if ((current
->signal
->tty
!= tty
) && !capable(CAP_SYS_ADMIN
))
2147 if (get_user(ch
, p
))
2149 tty_audit_tiocsti(tty
, ch
);
2150 ld
= tty_ldisc_ref_wait(tty
);
2153 ld
->ops
->receive_buf(tty
, &ch
, &mbz
, 1);
2154 tty_ldisc_deref(ld
);
2159 * tiocgwinsz - implement window query ioctl
2161 * @arg: user buffer for result
2163 * Copies the kernel idea of the window size into the user buffer.
2165 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2169 static int tiocgwinsz(struct tty_struct
*tty
, struct winsize __user
*arg
)
2173 mutex_lock(&tty
->winsize_mutex
);
2174 err
= copy_to_user(arg
, &tty
->winsize
, sizeof(*arg
));
2175 mutex_unlock(&tty
->winsize_mutex
);
2177 return err
? -EFAULT
: 0;
2181 * tty_do_resize - resize event
2182 * @tty: tty being resized
2183 * @rows: rows (character)
2184 * @cols: cols (character)
2186 * Update the termios variables and send the necessary signals to
2187 * peform a terminal resize correctly
2190 int tty_do_resize(struct tty_struct
*tty
, struct winsize
*ws
)
2195 mutex_lock(&tty
->winsize_mutex
);
2196 if (!memcmp(ws
, &tty
->winsize
, sizeof(*ws
)))
2199 /* Signal the foreground process group */
2200 pgrp
= tty_get_pgrp(tty
);
2202 kill_pgrp(pgrp
, SIGWINCH
, 1);
2207 mutex_unlock(&tty
->winsize_mutex
);
2210 EXPORT_SYMBOL(tty_do_resize
);
2213 * tiocswinsz - implement window size set ioctl
2214 * @tty; tty side of tty
2215 * @arg: user buffer for result
2217 * Copies the user idea of the window size to the kernel. Traditionally
2218 * this is just advisory information but for the Linux console it
2219 * actually has driver level meaning and triggers a VC resize.
2222 * Driver dependent. The default do_resize method takes the
2223 * tty termios mutex and ctrl_lock. The console takes its own lock
2224 * then calls into the default method.
2227 static int tiocswinsz(struct tty_struct
*tty
, struct winsize __user
*arg
)
2229 struct winsize tmp_ws
;
2230 if (copy_from_user(&tmp_ws
, arg
, sizeof(*arg
)))
2233 if (tty
->ops
->resize
)
2234 return tty
->ops
->resize(tty
, &tmp_ws
);
2236 return tty_do_resize(tty
, &tmp_ws
);
2240 * tioccons - allow admin to move logical console
2241 * @file: the file to become console
2243 * Allow the administrator to move the redirected console device
2245 * Locking: uses redirect_lock to guard the redirect information
2248 static int tioccons(struct file
*file
)
2250 if (!capable(CAP_SYS_ADMIN
))
2252 if (file
->f_op
->write
== redirected_tty_write
) {
2254 spin_lock(&redirect_lock
);
2257 spin_unlock(&redirect_lock
);
2262 spin_lock(&redirect_lock
);
2264 spin_unlock(&redirect_lock
);
2267 redirect
= get_file(file
);
2268 spin_unlock(&redirect_lock
);
2273 * fionbio - non blocking ioctl
2274 * @file: file to set blocking value
2275 * @p: user parameter
2277 * Historical tty interfaces had a blocking control ioctl before
2278 * the generic functionality existed. This piece of history is preserved
2279 * in the expected tty API of posix OS's.
2281 * Locking: none, the open file handle ensures it won't go away.
2284 static int fionbio(struct file
*file
, int __user
*p
)
2288 if (get_user(nonblock
, p
))
2291 spin_lock(&file
->f_lock
);
2293 file
->f_flags
|= O_NONBLOCK
;
2295 file
->f_flags
&= ~O_NONBLOCK
;
2296 spin_unlock(&file
->f_lock
);
2301 * tiocsetd - set line discipline
2303 * @p: pointer to user data
2305 * Set the line discipline according to user request.
2307 * Locking: see tty_set_ldisc, this function is just a helper
2310 static int tiocsetd(struct tty_struct
*tty
, int __user
*p
)
2315 if (get_user(disc
, p
))
2318 ret
= tty_set_ldisc(tty
, disc
);
2324 * tiocgetd - get line discipline
2326 * @p: pointer to user data
2328 * Retrieves the line discipline id directly from the ldisc.
2330 * Locking: waits for ldisc reference (in case the line discipline
2331 * is changing or the tty is being hungup)
2334 static int tiocgetd(struct tty_struct
*tty
, int __user
*p
)
2336 struct tty_ldisc
*ld
;
2339 ld
= tty_ldisc_ref_wait(tty
);
2342 ret
= put_user(ld
->ops
->num
, p
);
2343 tty_ldisc_deref(ld
);
2348 * send_break - performed time break
2349 * @tty: device to break on
2350 * @duration: timeout in mS
2352 * Perform a timed break on hardware that lacks its own driver level
2353 * timed break functionality.
2356 * atomic_write_lock serializes
2360 static int send_break(struct tty_struct
*tty
, unsigned int duration
)
2364 if (tty
->ops
->break_ctl
== NULL
)
2367 if (tty
->driver
->flags
& TTY_DRIVER_HARDWARE_BREAK
)
2368 retval
= tty
->ops
->break_ctl(tty
, duration
);
2370 /* Do the work ourselves */
2371 if (tty_write_lock(tty
, 0) < 0)
2373 retval
= tty
->ops
->break_ctl(tty
, -1);
2376 if (!signal_pending(current
))
2377 msleep_interruptible(duration
);
2378 retval
= tty
->ops
->break_ctl(tty
, 0);
2380 tty_write_unlock(tty
);
2381 if (signal_pending(current
))
2388 * tty_tiocmget - get modem status
2390 * @file: user file pointer
2391 * @p: pointer to result
2393 * Obtain the modem status bits from the tty driver if the feature
2394 * is supported. Return -EINVAL if it is not available.
2396 * Locking: none (up to the driver)
2399 static int tty_tiocmget(struct tty_struct
*tty
, int __user
*p
)
2401 int retval
= -EINVAL
;
2403 if (tty
->ops
->tiocmget
) {
2404 retval
= tty
->ops
->tiocmget(tty
);
2407 retval
= put_user(retval
, p
);
2413 * tty_tiocmset - set modem status
2415 * @cmd: command - clear bits, set bits or set all
2416 * @p: pointer to desired bits
2418 * Set the modem status bits from the tty driver if the feature
2419 * is supported. Return -EINVAL if it is not available.
2421 * Locking: none (up to the driver)
2424 static int tty_tiocmset(struct tty_struct
*tty
, unsigned int cmd
,
2428 unsigned int set
, clear
, val
;
2430 if (tty
->ops
->tiocmset
== NULL
)
2433 retval
= get_user(val
, p
);
2449 set
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
2450 clear
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
2451 return tty
->ops
->tiocmset(tty
, set
, clear
);
2454 static int tty_tiocgicount(struct tty_struct
*tty
, void __user
*arg
)
2456 int retval
= -EINVAL
;
2457 struct serial_icounter_struct icount
;
2458 memset(&icount
, 0, sizeof(icount
));
2459 if (tty
->ops
->get_icount
)
2460 retval
= tty
->ops
->get_icount(tty
, &icount
);
2463 if (copy_to_user(arg
, &icount
, sizeof(icount
)))
2468 static void tty_warn_deprecated_flags(struct serial_struct __user
*ss
)
2470 static DEFINE_RATELIMIT_STATE(depr_flags
,
2471 DEFAULT_RATELIMIT_INTERVAL
,
2472 DEFAULT_RATELIMIT_BURST
);
2473 char comm
[TASK_COMM_LEN
];
2476 if (get_user(flags
, &ss
->flags
))
2479 flags
&= ASYNC_DEPRECATED
;
2481 if (flags
&& __ratelimit(&depr_flags
))
2482 pr_warn("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2483 __func__
, get_task_comm(comm
, current
), flags
);
2487 * if pty, return the slave side (real_tty)
2488 * otherwise, return self
2490 static struct tty_struct
*tty_pair_get_tty(struct tty_struct
*tty
)
2492 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2493 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
2499 * Split this up, as gcc can choke on it otherwise..
2501 long tty_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
2503 struct tty_struct
*tty
= file_tty(file
);
2504 struct tty_struct
*real_tty
;
2505 void __user
*p
= (void __user
*)arg
;
2507 struct tty_ldisc
*ld
;
2509 if (tty_paranoia_check(tty
, file_inode(file
), "tty_ioctl"))
2512 real_tty
= tty_pair_get_tty(tty
);
2515 * Factor out some common prep work
2523 retval
= tty_check_change(tty
);
2526 if (cmd
!= TIOCCBRK
) {
2527 tty_wait_until_sent(tty
, 0);
2528 if (signal_pending(current
))
2539 return tiocsti(tty
, p
);
2541 return tiocgwinsz(real_tty
, p
);
2543 return tiocswinsz(real_tty
, p
);
2545 return real_tty
!= tty
? -EINVAL
: tioccons(file
);
2547 return fionbio(file
, p
);
2549 set_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2552 clear_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2556 int excl
= test_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2557 return put_user(excl
, (int __user
*)p
);
2560 return tiocgetd(tty
, p
);
2562 return tiocsetd(tty
, p
);
2564 if (!capable(CAP_SYS_ADMIN
))
2570 unsigned int ret
= new_encode_dev(tty_devnum(real_tty
));
2571 return put_user(ret
, (unsigned int __user
*)p
);
2576 case TIOCSBRK
: /* Turn break on, unconditionally */
2577 if (tty
->ops
->break_ctl
)
2578 return tty
->ops
->break_ctl(tty
, -1);
2580 case TIOCCBRK
: /* Turn break off, unconditionally */
2581 if (tty
->ops
->break_ctl
)
2582 return tty
->ops
->break_ctl(tty
, 0);
2584 case TCSBRK
: /* SVID version: non-zero arg --> no break */
2585 /* non-zero arg means wait for all output data
2586 * to be sent (performed above) but don't send break.
2587 * This is used by the tcdrain() termios function.
2590 return send_break(tty
, 250);
2592 case TCSBRKP
: /* support for POSIX tcsendbreak() */
2593 return send_break(tty
, arg
? arg
*100 : 250);
2596 return tty_tiocmget(tty
, p
);
2600 return tty_tiocmset(tty
, cmd
, p
);
2602 retval
= tty_tiocgicount(tty
, p
);
2603 /* For the moment allow fall through to the old method */
2604 if (retval
!= -EINVAL
)
2611 /* flush tty buffer and allow ldisc to process ioctl */
2612 tty_buffer_flush(tty
, NULL
);
2617 tty_warn_deprecated_flags(p
);
2620 /* Special because the struct file is needed */
2621 return ptm_open_peer(file
, tty
, (int)arg
);
2623 retval
= tty_jobctrl_ioctl(tty
, real_tty
, file
, cmd
, arg
);
2624 if (retval
!= -ENOIOCTLCMD
)
2627 if (tty
->ops
->ioctl
) {
2628 retval
= tty
->ops
->ioctl(tty
, cmd
, arg
);
2629 if (retval
!= -ENOIOCTLCMD
)
2632 ld
= tty_ldisc_ref_wait(tty
);
2634 return hung_up_tty_ioctl(file
, cmd
, arg
);
2636 if (ld
->ops
->ioctl
) {
2637 retval
= ld
->ops
->ioctl(tty
, file
, cmd
, arg
);
2638 if (retval
== -ENOIOCTLCMD
)
2641 tty_ldisc_deref(ld
);
2645 #ifdef CONFIG_COMPAT
2646 static long tty_compat_ioctl(struct file
*file
, unsigned int cmd
,
2649 struct tty_struct
*tty
= file_tty(file
);
2650 struct tty_ldisc
*ld
;
2651 int retval
= -ENOIOCTLCMD
;
2653 if (tty_paranoia_check(tty
, file_inode(file
), "tty_ioctl"))
2656 if (tty
->ops
->compat_ioctl
) {
2657 retval
= tty
->ops
->compat_ioctl(tty
, cmd
, arg
);
2658 if (retval
!= -ENOIOCTLCMD
)
2662 ld
= tty_ldisc_ref_wait(tty
);
2664 return hung_up_tty_compat_ioctl(file
, cmd
, arg
);
2665 if (ld
->ops
->compat_ioctl
)
2666 retval
= ld
->ops
->compat_ioctl(tty
, file
, cmd
, arg
);
2668 retval
= n_tty_compat_ioctl_helper(tty
, file
, cmd
, arg
);
2669 tty_ldisc_deref(ld
);
2675 static int this_tty(const void *t
, struct file
*file
, unsigned fd
)
2677 if (likely(file
->f_op
->read
!= tty_read
))
2679 return file_tty(file
) != t
? 0 : fd
+ 1;
2683 * This implements the "Secure Attention Key" --- the idea is to
2684 * prevent trojan horses by killing all processes associated with this
2685 * tty when the user hits the "Secure Attention Key". Required for
2686 * super-paranoid applications --- see the Orange Book for more details.
2688 * This code could be nicer; ideally it should send a HUP, wait a few
2689 * seconds, then send a INT, and then a KILL signal. But you then
2690 * have to coordinate with the init process, since all processes associated
2691 * with the current tty must be dead before the new getty is allowed
2694 * Now, if it would be correct ;-/ The current code has a nasty hole -
2695 * it doesn't catch files in flight. We may send the descriptor to ourselves
2696 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2698 * Nasty bug: do_SAK is being called in interrupt context. This can
2699 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2701 void __do_SAK(struct tty_struct
*tty
)
2706 struct task_struct
*g
, *p
;
2707 struct pid
*session
;
2712 session
= tty
->session
;
2714 tty_ldisc_flush(tty
);
2716 tty_driver_flush_buffer(tty
);
2718 read_lock(&tasklist_lock
);
2719 /* Kill the entire session */
2720 do_each_pid_task(session
, PIDTYPE_SID
, p
) {
2721 tty_notice(tty
, "SAK: killed process %d (%s): by session\n",
2722 task_pid_nr(p
), p
->comm
);
2723 send_sig(SIGKILL
, p
, 1);
2724 } while_each_pid_task(session
, PIDTYPE_SID
, p
);
2726 /* Now kill any processes that happen to have the tty open */
2727 do_each_thread(g
, p
) {
2728 if (p
->signal
->tty
== tty
) {
2729 tty_notice(tty
, "SAK: killed process %d (%s): by controlling tty\n",
2730 task_pid_nr(p
), p
->comm
);
2731 send_sig(SIGKILL
, p
, 1);
2735 i
= iterate_fd(p
->files
, 0, this_tty
, tty
);
2737 tty_notice(tty
, "SAK: killed process %d (%s): by fd#%d\n",
2738 task_pid_nr(p
), p
->comm
, i
- 1);
2739 force_sig(SIGKILL
, p
);
2742 } while_each_thread(g
, p
);
2743 read_unlock(&tasklist_lock
);
2747 static void do_SAK_work(struct work_struct
*work
)
2749 struct tty_struct
*tty
=
2750 container_of(work
, struct tty_struct
, SAK_work
);
2755 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2756 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2757 * the values which we write to it will be identical to the values which it
2758 * already has. --akpm
2760 void do_SAK(struct tty_struct
*tty
)
2764 schedule_work(&tty
->SAK_work
);
2767 EXPORT_SYMBOL(do_SAK
);
2769 static int dev_match_devt(struct device
*dev
, const void *data
)
2771 const dev_t
*devt
= data
;
2772 return dev
->devt
== *devt
;
2775 /* Must put_device() after it's unused! */
2776 static struct device
*tty_get_device(struct tty_struct
*tty
)
2778 dev_t devt
= tty_devnum(tty
);
2779 return class_find_device(tty_class
, NULL
, &devt
, dev_match_devt
);
2786 * This subroutine allocates and initializes a tty structure.
2788 * Locking: none - tty in question is not exposed at this point
2791 struct tty_struct
*alloc_tty_struct(struct tty_driver
*driver
, int idx
)
2793 struct tty_struct
*tty
;
2795 tty
= kzalloc(sizeof(*tty
), GFP_KERNEL
);
2799 kref_init(&tty
->kref
);
2800 tty
->magic
= TTY_MAGIC
;
2801 tty_ldisc_init(tty
);
2802 tty
->session
= NULL
;
2804 mutex_init(&tty
->legacy_mutex
);
2805 mutex_init(&tty
->throttle_mutex
);
2806 init_rwsem(&tty
->termios_rwsem
);
2807 mutex_init(&tty
->winsize_mutex
);
2808 init_ldsem(&tty
->ldisc_sem
);
2809 init_waitqueue_head(&tty
->write_wait
);
2810 init_waitqueue_head(&tty
->read_wait
);
2811 INIT_WORK(&tty
->hangup_work
, do_tty_hangup
);
2812 mutex_init(&tty
->atomic_write_lock
);
2813 spin_lock_init(&tty
->ctrl_lock
);
2814 spin_lock_init(&tty
->flow_lock
);
2815 spin_lock_init(&tty
->files_lock
);
2816 INIT_LIST_HEAD(&tty
->tty_files
);
2817 INIT_WORK(&tty
->SAK_work
, do_SAK_work
);
2819 tty
->driver
= driver
;
2820 tty
->ops
= driver
->ops
;
2822 tty_line_name(driver
, idx
, tty
->name
);
2823 tty
->dev
= tty_get_device(tty
);
2829 * tty_put_char - write one character to a tty
2833 * Write one byte to the tty using the provided put_char method
2834 * if present. Returns the number of characters successfully output.
2836 * Note: the specific put_char operation in the driver layer may go
2837 * away soon. Don't call it directly, use this method
2840 int tty_put_char(struct tty_struct
*tty
, unsigned char ch
)
2842 if (tty
->ops
->put_char
)
2843 return tty
->ops
->put_char(tty
, ch
);
2844 return tty
->ops
->write(tty
, &ch
, 1);
2846 EXPORT_SYMBOL_GPL(tty_put_char
);
2848 struct class *tty_class
;
2850 static int tty_cdev_add(struct tty_driver
*driver
, dev_t dev
,
2851 unsigned int index
, unsigned int count
)
2855 /* init here, since reused cdevs cause crashes */
2856 driver
->cdevs
[index
] = cdev_alloc();
2857 if (!driver
->cdevs
[index
])
2859 driver
->cdevs
[index
]->ops
= &tty_fops
;
2860 driver
->cdevs
[index
]->owner
= driver
->owner
;
2861 err
= cdev_add(driver
->cdevs
[index
], dev
, count
);
2863 kobject_put(&driver
->cdevs
[index
]->kobj
);
2868 * tty_register_device - register a tty device
2869 * @driver: the tty driver that describes the tty device
2870 * @index: the index in the tty driver for this tty device
2871 * @device: a struct device that is associated with this tty device.
2872 * This field is optional, if there is no known struct device
2873 * for this tty device it can be set to NULL safely.
2875 * Returns a pointer to the struct device for this tty device
2876 * (or ERR_PTR(-EFOO) on error).
2878 * This call is required to be made to register an individual tty device
2879 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2880 * that bit is not set, this function should not be called by a tty
2886 struct device
*tty_register_device(struct tty_driver
*driver
, unsigned index
,
2887 struct device
*device
)
2889 return tty_register_device_attr(driver
, index
, device
, NULL
, NULL
);
2891 EXPORT_SYMBOL(tty_register_device
);
2893 static void tty_device_create_release(struct device
*dev
)
2895 dev_dbg(dev
, "releasing...\n");
2900 * tty_register_device_attr - register a tty device
2901 * @driver: the tty driver that describes the tty device
2902 * @index: the index in the tty driver for this tty device
2903 * @device: a struct device that is associated with this tty device.
2904 * This field is optional, if there is no known struct device
2905 * for this tty device it can be set to NULL safely.
2906 * @drvdata: Driver data to be set to device.
2907 * @attr_grp: Attribute group to be set on device.
2909 * Returns a pointer to the struct device for this tty device
2910 * (or ERR_PTR(-EFOO) on error).
2912 * This call is required to be made to register an individual tty device
2913 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2914 * that bit is not set, this function should not be called by a tty
2919 struct device
*tty_register_device_attr(struct tty_driver
*driver
,
2920 unsigned index
, struct device
*device
,
2922 const struct attribute_group
**attr_grp
)
2925 dev_t devt
= MKDEV(driver
->major
, driver
->minor_start
) + index
;
2926 struct ktermios
*tp
;
2930 if (index
>= driver
->num
) {
2931 pr_err("%s: Attempt to register invalid tty line number (%d)\n",
2932 driver
->name
, index
);
2933 return ERR_PTR(-EINVAL
);
2936 if (driver
->type
== TTY_DRIVER_TYPE_PTY
)
2937 pty_line_name(driver
, index
, name
);
2939 tty_line_name(driver
, index
, name
);
2941 dev
= kzalloc(sizeof(*dev
), GFP_KERNEL
);
2943 return ERR_PTR(-ENOMEM
);
2946 dev
->class = tty_class
;
2947 dev
->parent
= device
;
2948 dev
->release
= tty_device_create_release
;
2949 dev_set_name(dev
, "%s", name
);
2950 dev
->groups
= attr_grp
;
2951 dev_set_drvdata(dev
, drvdata
);
2953 dev_set_uevent_suppress(dev
, 1);
2955 retval
= device_register(dev
);
2959 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
)) {
2961 * Free any saved termios data so that the termios state is
2962 * reset when reusing a minor number.
2964 tp
= driver
->termios
[index
];
2966 driver
->termios
[index
] = NULL
;
2970 retval
= tty_cdev_add(driver
, devt
, index
, 1);
2975 dev_set_uevent_suppress(dev
, 0);
2976 kobject_uevent(&dev
->kobj
, KOBJ_ADD
);
2985 return ERR_PTR(retval
);
2987 EXPORT_SYMBOL_GPL(tty_register_device_attr
);
2990 * tty_unregister_device - unregister a tty device
2991 * @driver: the tty driver that describes the tty device
2992 * @index: the index in the tty driver for this tty device
2994 * If a tty device is registered with a call to tty_register_device() then
2995 * this function must be called when the tty device is gone.
3000 void tty_unregister_device(struct tty_driver
*driver
, unsigned index
)
3002 device_destroy(tty_class
,
3003 MKDEV(driver
->major
, driver
->minor_start
) + index
);
3004 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
)) {
3005 cdev_del(driver
->cdevs
[index
]);
3006 driver
->cdevs
[index
] = NULL
;
3009 EXPORT_SYMBOL(tty_unregister_device
);
3012 * __tty_alloc_driver -- allocate tty driver
3013 * @lines: count of lines this driver can handle at most
3014 * @owner: module which is responsible for this driver
3015 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3017 * This should not be called directly, some of the provided macros should be
3018 * used instead. Use IS_ERR and friends on @retval.
3020 struct tty_driver
*__tty_alloc_driver(unsigned int lines
, struct module
*owner
,
3021 unsigned long flags
)
3023 struct tty_driver
*driver
;
3024 unsigned int cdevs
= 1;
3027 if (!lines
|| (flags
& TTY_DRIVER_UNNUMBERED_NODE
&& lines
> 1))
3028 return ERR_PTR(-EINVAL
);
3030 driver
= kzalloc(sizeof(struct tty_driver
), GFP_KERNEL
);
3032 return ERR_PTR(-ENOMEM
);
3034 kref_init(&driver
->kref
);
3035 driver
->magic
= TTY_DRIVER_MAGIC
;
3036 driver
->num
= lines
;
3037 driver
->owner
= owner
;
3038 driver
->flags
= flags
;
3040 if (!(flags
& TTY_DRIVER_DEVPTS_MEM
)) {
3041 driver
->ttys
= kcalloc(lines
, sizeof(*driver
->ttys
),
3043 driver
->termios
= kcalloc(lines
, sizeof(*driver
->termios
),
3045 if (!driver
->ttys
|| !driver
->termios
) {
3051 if (!(flags
& TTY_DRIVER_DYNAMIC_ALLOC
)) {
3052 driver
->ports
= kcalloc(lines
, sizeof(*driver
->ports
),
3054 if (!driver
->ports
) {
3061 driver
->cdevs
= kcalloc(cdevs
, sizeof(*driver
->cdevs
), GFP_KERNEL
);
3062 if (!driver
->cdevs
) {
3069 kfree(driver
->ports
);
3070 kfree(driver
->ttys
);
3071 kfree(driver
->termios
);
3072 kfree(driver
->cdevs
);
3074 return ERR_PTR(err
);
3076 EXPORT_SYMBOL(__tty_alloc_driver
);
3078 static void destruct_tty_driver(struct kref
*kref
)
3080 struct tty_driver
*driver
= container_of(kref
, struct tty_driver
, kref
);
3082 struct ktermios
*tp
;
3084 if (driver
->flags
& TTY_DRIVER_INSTALLED
) {
3085 for (i
= 0; i
< driver
->num
; i
++) {
3086 tp
= driver
->termios
[i
];
3088 driver
->termios
[i
] = NULL
;
3091 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
))
3092 tty_unregister_device(driver
, i
);
3094 proc_tty_unregister_driver(driver
);
3095 if (driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
)
3096 cdev_del(driver
->cdevs
[0]);
3098 kfree(driver
->cdevs
);
3099 kfree(driver
->ports
);
3100 kfree(driver
->termios
);
3101 kfree(driver
->ttys
);
3105 void tty_driver_kref_put(struct tty_driver
*driver
)
3107 kref_put(&driver
->kref
, destruct_tty_driver
);
3109 EXPORT_SYMBOL(tty_driver_kref_put
);
3111 void tty_set_operations(struct tty_driver
*driver
,
3112 const struct tty_operations
*op
)
3116 EXPORT_SYMBOL(tty_set_operations
);
3118 void put_tty_driver(struct tty_driver
*d
)
3120 tty_driver_kref_put(d
);
3122 EXPORT_SYMBOL(put_tty_driver
);
3125 * Called by a tty driver to register itself.
3127 int tty_register_driver(struct tty_driver
*driver
)
3134 if (!driver
->major
) {
3135 error
= alloc_chrdev_region(&dev
, driver
->minor_start
,
3136 driver
->num
, driver
->name
);
3138 driver
->major
= MAJOR(dev
);
3139 driver
->minor_start
= MINOR(dev
);
3142 dev
= MKDEV(driver
->major
, driver
->minor_start
);
3143 error
= register_chrdev_region(dev
, driver
->num
, driver
->name
);
3148 if (driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
) {
3149 error
= tty_cdev_add(driver
, dev
, 0, driver
->num
);
3151 goto err_unreg_char
;
3154 mutex_lock(&tty_mutex
);
3155 list_add(&driver
->tty_drivers
, &tty_drivers
);
3156 mutex_unlock(&tty_mutex
);
3158 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
)) {
3159 for (i
= 0; i
< driver
->num
; i
++) {
3160 d
= tty_register_device(driver
, i
, NULL
);
3163 goto err_unreg_devs
;
3167 proc_tty_register_driver(driver
);
3168 driver
->flags
|= TTY_DRIVER_INSTALLED
;
3172 for (i
--; i
>= 0; i
--)
3173 tty_unregister_device(driver
, i
);
3175 mutex_lock(&tty_mutex
);
3176 list_del(&driver
->tty_drivers
);
3177 mutex_unlock(&tty_mutex
);
3180 unregister_chrdev_region(dev
, driver
->num
);
3184 EXPORT_SYMBOL(tty_register_driver
);
3187 * Called by a tty driver to unregister itself.
3189 int tty_unregister_driver(struct tty_driver
*driver
)
3193 if (driver
->refcount
)
3196 unregister_chrdev_region(MKDEV(driver
->major
, driver
->minor_start
),
3198 mutex_lock(&tty_mutex
);
3199 list_del(&driver
->tty_drivers
);
3200 mutex_unlock(&tty_mutex
);
3204 EXPORT_SYMBOL(tty_unregister_driver
);
3206 dev_t
tty_devnum(struct tty_struct
*tty
)
3208 return MKDEV(tty
->driver
->major
, tty
->driver
->minor_start
) + tty
->index
;
3210 EXPORT_SYMBOL(tty_devnum
);
3212 void tty_default_fops(struct file_operations
*fops
)
3217 static char *tty_devnode(struct device
*dev
, umode_t
*mode
)
3221 if (dev
->devt
== MKDEV(TTYAUX_MAJOR
, 0) ||
3222 dev
->devt
== MKDEV(TTYAUX_MAJOR
, 2))
3227 static int __init
tty_class_init(void)
3229 tty_class
= class_create(THIS_MODULE
, "tty");
3230 if (IS_ERR(tty_class
))
3231 return PTR_ERR(tty_class
);
3232 tty_class
->devnode
= tty_devnode
;
3236 postcore_initcall(tty_class_init
);
3238 /* 3/2004 jmc: why do these devices exist? */
3239 static struct cdev tty_cdev
, console_cdev
;
3241 static ssize_t
show_cons_active(struct device
*dev
,
3242 struct device_attribute
*attr
, char *buf
)
3244 struct console
*cs
[16];
3250 for_each_console(c
) {
3255 if ((c
->flags
& CON_ENABLED
) == 0)
3258 if (i
>= ARRAY_SIZE(cs
))
3262 int index
= cs
[i
]->index
;
3263 struct tty_driver
*drv
= cs
[i
]->device(cs
[i
], &index
);
3265 /* don't resolve tty0 as some programs depend on it */
3266 if (drv
&& (cs
[i
]->index
> 0 || drv
->major
!= TTY_MAJOR
))
3267 count
+= tty_line_name(drv
, index
, buf
+ count
);
3269 count
+= sprintf(buf
+ count
, "%s%d",
3270 cs
[i
]->name
, cs
[i
]->index
);
3272 count
+= sprintf(buf
+ count
, "%c", i
? ' ':'\n');
3278 static DEVICE_ATTR(active
, S_IRUGO
, show_cons_active
, NULL
);
3280 static struct attribute
*cons_dev_attrs
[] = {
3281 &dev_attr_active
.attr
,
3285 ATTRIBUTE_GROUPS(cons_dev
);
3287 static struct device
*consdev
;
3289 void console_sysfs_notify(void)
3292 sysfs_notify(&consdev
->kobj
, NULL
, "active");
3296 * Ok, now we can initialize the rest of the tty devices and can count
3297 * on memory allocations, interrupts etc..
3299 int __init
tty_init(void)
3301 cdev_init(&tty_cdev
, &tty_fops
);
3302 if (cdev_add(&tty_cdev
, MKDEV(TTYAUX_MAJOR
, 0), 1) ||
3303 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 0), 1, "/dev/tty") < 0)
3304 panic("Couldn't register /dev/tty driver\n");
3305 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 0), NULL
, "tty");
3307 cdev_init(&console_cdev
, &console_fops
);
3308 if (cdev_add(&console_cdev
, MKDEV(TTYAUX_MAJOR
, 1), 1) ||
3309 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 1), 1, "/dev/console") < 0)
3310 panic("Couldn't register /dev/console driver\n");
3311 consdev
= device_create_with_groups(tty_class
, NULL
,
3312 MKDEV(TTYAUX_MAJOR
, 1), NULL
,
3313 cons_dev_groups
, "console");
3314 if (IS_ERR(consdev
))
3318 vty_init(&console_fops
);