1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 1991, 1992 Linus Torvalds
7 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
8 * or rs-channels. It also implements echoing, cooked mode etc.
10 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
12 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
13 * tty_struct and tty_queue structures. Previously there was an array
14 * of 256 tty_struct's which was statically allocated, and the
15 * tty_queue structures were allocated at boot time. Both are now
16 * dynamically allocated only when the tty is open.
18 * Also restructured routines so that there is more of a separation
19 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
20 * the low-level tty routines (serial.c, pty.c, console.c). This
21 * makes for cleaner and more compact code. -TYT, 9/17/92
23 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
24 * which can be dynamically activated and de-activated by the line
25 * discipline handling modules (like SLIP).
27 * NOTE: pay no attention to the line discipline code (yet); its
28 * interface is still subject to change in this version...
31 * Added functionality to the OPOST tty handling. No delays, but all
32 * other bits should be there.
33 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
35 * Rewrote canonical mode and added more termios flags.
36 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
38 * Reorganized FASYNC support so mouse code can share it.
39 * -- ctm@ardi.com, 9Sep95
41 * New TIOCLINUX variants added.
42 * -- mj@k332.feld.cvut.cz, 19-Nov-95
44 * Restrict vt switching via ioctl()
45 * -- grif@cs.ucr.edu, 5-Dec-95
47 * Move console and virtual terminal code to more appropriate files,
48 * implement CONFIG_VT and generalize console device interface.
49 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
51 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
52 * -- Bill Hawes <whawes@star.net>, June 97
54 * Added devfs support.
55 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
57 * Added support for a Unix98-style ptmx device.
58 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
60 * Reduced memory usage for older ARM systems
61 * -- Russell King <rmk@arm.linux.org.uk>
63 * Move do_SAK() into process context. Less stack use in devfs functions.
64 * alloc_tty_struct() always uses kmalloc()
65 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
68 #include <linux/types.h>
69 #include <linux/major.h>
70 #include <linux/errno.h>
71 #include <linux/signal.h>
72 #include <linux/fcntl.h>
73 #include <linux/sched/signal.h>
74 #include <linux/sched/task.h>
75 #include <linux/interrupt.h>
76 #include <linux/tty.h>
77 #include <linux/tty_driver.h>
78 #include <linux/tty_flip.h>
79 #include <linux/devpts_fs.h>
80 #include <linux/file.h>
81 #include <linux/fdtable.h>
82 #include <linux/console.h>
83 #include <linux/timer.h>
84 #include <linux/ctype.h>
87 #include <linux/string.h>
88 #include <linux/slab.h>
89 #include <linux/poll.h>
90 #include <linux/proc_fs.h>
91 #include <linux/init.h>
92 #include <linux/module.h>
93 #include <linux/device.h>
94 #include <linux/wait.h>
95 #include <linux/bitops.h>
96 #include <linux/delay.h>
97 #include <linux/seq_file.h>
98 #include <linux/serial.h>
99 #include <linux/ratelimit.h>
101 #include <linux/uaccess.h>
103 #include <linux/kbd_kern.h>
104 #include <linux/vt_kern.h>
105 #include <linux/selection.h>
107 #include <linux/kmod.h>
108 #include <linux/nsproxy.h>
110 #undef TTY_DEBUG_HANGUP
111 #ifdef TTY_DEBUG_HANGUP
112 # define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args)
114 # define tty_debug_hangup(tty, f, args...) do { } while (0)
117 #define TTY_PARANOIA_CHECK 1
118 #define CHECK_TTY_COUNT 1
120 struct ktermios tty_std_termios
= { /* for the benefit of tty drivers */
121 .c_iflag
= ICRNL
| IXON
,
122 .c_oflag
= OPOST
| ONLCR
,
123 .c_cflag
= B38400
| CS8
| CREAD
| HUPCL
,
124 .c_lflag
= ISIG
| ICANON
| ECHO
| ECHOE
| ECHOK
|
125 ECHOCTL
| ECHOKE
| IEXTEN
,
129 /* .c_line = N_TTY, */
132 EXPORT_SYMBOL(tty_std_termios
);
134 /* This list gets poked at by procfs and various bits of boot up code. This
135 could do with some rationalisation such as pulling the tty proc function
138 LIST_HEAD(tty_drivers
); /* linked list of tty drivers */
140 /* Mutex to protect creating and releasing a tty */
141 DEFINE_MUTEX(tty_mutex
);
143 static ssize_t
tty_read(struct file
*, char __user
*, size_t, loff_t
*);
144 static ssize_t
tty_write(struct file
*, const char __user
*, size_t, loff_t
*);
145 ssize_t
redirected_tty_write(struct file
*, const char __user
*,
147 static unsigned int tty_poll(struct file
*, poll_table
*);
148 static int tty_open(struct inode
*, struct file
*);
149 long tty_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
);
151 static long tty_compat_ioctl(struct file
*file
, unsigned int cmd
,
154 #define tty_compat_ioctl NULL
156 static int __tty_fasync(int fd
, struct file
*filp
, int on
);
157 static int tty_fasync(int fd
, struct file
*filp
, int on
);
158 static void release_tty(struct tty_struct
*tty
, int idx
);
161 * free_tty_struct - free a disused tty
162 * @tty: tty struct to free
164 * Free the write buffers, tty queue and tty memory itself.
166 * Locking: none. Must be called after tty is definitely unused
169 static void free_tty_struct(struct tty_struct
*tty
)
171 tty_ldisc_deinit(tty
);
172 put_device(tty
->dev
);
173 kfree(tty
->write_buf
);
174 tty
->magic
= 0xDEADDEAD;
178 static inline struct tty_struct
*file_tty(struct file
*file
)
180 return ((struct tty_file_private
*)file
->private_data
)->tty
;
183 int tty_alloc_file(struct file
*file
)
185 struct tty_file_private
*priv
;
187 priv
= kmalloc(sizeof(*priv
), GFP_KERNEL
);
191 file
->private_data
= priv
;
196 /* Associate a new file with the tty structure */
197 void tty_add_file(struct tty_struct
*tty
, struct file
*file
)
199 struct tty_file_private
*priv
= file
->private_data
;
204 spin_lock(&tty
->files_lock
);
205 list_add(&priv
->list
, &tty
->tty_files
);
206 spin_unlock(&tty
->files_lock
);
210 * tty_free_file - free file->private_data
212 * This shall be used only for fail path handling when tty_add_file was not
215 void tty_free_file(struct file
*file
)
217 struct tty_file_private
*priv
= file
->private_data
;
219 file
->private_data
= NULL
;
223 /* Delete file from its tty */
224 static void tty_del_file(struct file
*file
)
226 struct tty_file_private
*priv
= file
->private_data
;
227 struct tty_struct
*tty
= priv
->tty
;
229 spin_lock(&tty
->files_lock
);
230 list_del(&priv
->list
);
231 spin_unlock(&tty
->files_lock
);
236 * tty_name - return tty naming
237 * @tty: tty structure
239 * Convert a tty structure into a name. The name reflects the kernel
240 * naming policy and if udev is in use may not reflect user space
245 const char *tty_name(const struct tty_struct
*tty
)
247 if (!tty
) /* Hmm. NULL pointer. That's fun. */
252 EXPORT_SYMBOL(tty_name
);
254 const char *tty_driver_name(const struct tty_struct
*tty
)
256 if (!tty
|| !tty
->driver
)
258 return tty
->driver
->name
;
261 static int tty_paranoia_check(struct tty_struct
*tty
, struct inode
*inode
,
264 #ifdef TTY_PARANOIA_CHECK
266 pr_warn("(%d:%d): %s: NULL tty\n",
267 imajor(inode
), iminor(inode
), routine
);
270 if (tty
->magic
!= TTY_MAGIC
) {
271 pr_warn("(%d:%d): %s: bad magic number\n",
272 imajor(inode
), iminor(inode
), routine
);
279 /* Caller must hold tty_lock */
280 static int check_tty_count(struct tty_struct
*tty
, const char *routine
)
282 #ifdef CHECK_TTY_COUNT
284 int count
= 0, kopen_count
= 0;
286 spin_lock(&tty
->files_lock
);
287 list_for_each(p
, &tty
->tty_files
) {
290 spin_unlock(&tty
->files_lock
);
291 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
292 tty
->driver
->subtype
== PTY_TYPE_SLAVE
&&
293 tty
->link
&& tty
->link
->count
)
295 if (tty_port_kopened(tty
->port
))
297 if (tty
->count
!= (count
+ kopen_count
)) {
298 tty_warn(tty
, "%s: tty->count(%d) != (#fd's(%d) + #kopen's(%d))\n",
299 routine
, tty
->count
, count
, kopen_count
);
300 return (count
+ kopen_count
);
307 * get_tty_driver - find device of a tty
308 * @dev_t: device identifier
309 * @index: returns the index of the tty
311 * This routine returns a tty driver structure, given a device number
312 * and also passes back the index number.
314 * Locking: caller must hold tty_mutex
317 static struct tty_driver
*get_tty_driver(dev_t device
, int *index
)
319 struct tty_driver
*p
;
321 list_for_each_entry(p
, &tty_drivers
, tty_drivers
) {
322 dev_t base
= MKDEV(p
->major
, p
->minor_start
);
323 if (device
< base
|| device
>= base
+ p
->num
)
325 *index
= device
- base
;
326 return tty_driver_kref_get(p
);
332 * tty_dev_name_to_number - return dev_t for device name
333 * @name: user space name of device under /dev
334 * @number: pointer to dev_t that this function will populate
336 * This function converts device names like ttyS0 or ttyUSB1 into dev_t
337 * like (4, 64) or (188, 1). If no corresponding driver is registered then
338 * the function returns -ENODEV.
340 * Locking: this acquires tty_mutex to protect the tty_drivers list from
341 * being modified while we are traversing it, and makes sure to
342 * release it before exiting.
344 int tty_dev_name_to_number(const char *name
, dev_t
*number
)
346 struct tty_driver
*p
;
348 int index
, prefix_length
= 0;
351 for (str
= name
; *str
&& !isdigit(*str
); str
++)
357 ret
= kstrtoint(str
, 10, &index
);
361 prefix_length
= str
- name
;
362 mutex_lock(&tty_mutex
);
364 list_for_each_entry(p
, &tty_drivers
, tty_drivers
)
365 if (prefix_length
== strlen(p
->name
) && strncmp(name
,
366 p
->name
, prefix_length
) == 0) {
367 if (index
< p
->num
) {
368 *number
= MKDEV(p
->major
, p
->minor_start
+ index
);
373 /* if here then driver wasn't found */
376 mutex_unlock(&tty_mutex
);
379 EXPORT_SYMBOL_GPL(tty_dev_name_to_number
);
381 #ifdef CONFIG_CONSOLE_POLL
384 * tty_find_polling_driver - find device of a polled tty
385 * @name: name string to match
386 * @line: pointer to resulting tty line nr
388 * This routine returns a tty driver structure, given a name
389 * and the condition that the tty driver is capable of polled
392 struct tty_driver
*tty_find_polling_driver(char *name
, int *line
)
394 struct tty_driver
*p
, *res
= NULL
;
399 for (str
= name
; *str
; str
++)
400 if ((*str
>= '0' && *str
<= '9') || *str
== ',')
406 tty_line
= simple_strtoul(str
, &str
, 10);
408 mutex_lock(&tty_mutex
);
409 /* Search through the tty devices to look for a match */
410 list_for_each_entry(p
, &tty_drivers
, tty_drivers
) {
411 if (strncmp(name
, p
->name
, len
) != 0)
419 if (tty_line
>= 0 && tty_line
< p
->num
&& p
->ops
&&
420 p
->ops
->poll_init
&& !p
->ops
->poll_init(p
, tty_line
, stp
)) {
421 res
= tty_driver_kref_get(p
);
426 mutex_unlock(&tty_mutex
);
430 EXPORT_SYMBOL_GPL(tty_find_polling_driver
);
433 static ssize_t
hung_up_tty_read(struct file
*file
, char __user
*buf
,
434 size_t count
, loff_t
*ppos
)
439 static ssize_t
hung_up_tty_write(struct file
*file
, const char __user
*buf
,
440 size_t count
, loff_t
*ppos
)
445 /* No kernel lock held - none needed ;) */
446 static unsigned int hung_up_tty_poll(struct file
*filp
, poll_table
*wait
)
448 return POLLIN
| POLLOUT
| POLLERR
| POLLHUP
| POLLRDNORM
| POLLWRNORM
;
451 static long hung_up_tty_ioctl(struct file
*file
, unsigned int cmd
,
454 return cmd
== TIOCSPGRP
? -ENOTTY
: -EIO
;
457 static long hung_up_tty_compat_ioctl(struct file
*file
,
458 unsigned int cmd
, unsigned long arg
)
460 return cmd
== TIOCSPGRP
? -ENOTTY
: -EIO
;
463 static int hung_up_tty_fasync(int fd
, struct file
*file
, int on
)
468 static void tty_show_fdinfo(struct seq_file
*m
, struct file
*file
)
470 struct tty_struct
*tty
= file_tty(file
);
472 if (tty
&& tty
->ops
&& tty
->ops
->show_fdinfo
)
473 tty
->ops
->show_fdinfo(tty
, m
);
476 static const struct file_operations tty_fops
= {
481 .unlocked_ioctl
= tty_ioctl
,
482 .compat_ioctl
= tty_compat_ioctl
,
484 .release
= tty_release
,
485 .fasync
= tty_fasync
,
486 .show_fdinfo
= tty_show_fdinfo
,
489 static const struct file_operations console_fops
= {
492 .write
= redirected_tty_write
,
494 .unlocked_ioctl
= tty_ioctl
,
495 .compat_ioctl
= tty_compat_ioctl
,
497 .release
= tty_release
,
498 .fasync
= tty_fasync
,
501 static const struct file_operations hung_up_tty_fops
= {
503 .read
= hung_up_tty_read
,
504 .write
= hung_up_tty_write
,
505 .poll
= hung_up_tty_poll
,
506 .unlocked_ioctl
= hung_up_tty_ioctl
,
507 .compat_ioctl
= hung_up_tty_compat_ioctl
,
508 .release
= tty_release
,
509 .fasync
= hung_up_tty_fasync
,
512 static DEFINE_SPINLOCK(redirect_lock
);
513 static struct file
*redirect
;
516 * tty_wakeup - request more data
519 * Internal and external helper for wakeups of tty. This function
520 * informs the line discipline if present that the driver is ready
521 * to receive more output data.
524 void tty_wakeup(struct tty_struct
*tty
)
526 struct tty_ldisc
*ld
;
528 if (test_bit(TTY_DO_WRITE_WAKEUP
, &tty
->flags
)) {
529 ld
= tty_ldisc_ref(tty
);
531 if (ld
->ops
->write_wakeup
)
532 ld
->ops
->write_wakeup(tty
);
536 wake_up_interruptible_poll(&tty
->write_wait
, POLLOUT
);
539 EXPORT_SYMBOL_GPL(tty_wakeup
);
542 * __tty_hangup - actual handler for hangup events
545 * This can be called by a "kworker" kernel thread. That is process
546 * synchronous but doesn't hold any locks, so we need to make sure we
547 * have the appropriate locks for what we're doing.
549 * The hangup event clears any pending redirections onto the hung up
550 * device. It ensures future writes will error and it does the needed
551 * line discipline hangup and signal delivery. The tty object itself
556 * redirect lock for undoing redirection
557 * file list lock for manipulating list of ttys
558 * tty_ldiscs_lock from called functions
559 * termios_rwsem resetting termios data
560 * tasklist_lock to walk task list for hangup event
561 * ->siglock to protect ->signal/->sighand
563 static void __tty_hangup(struct tty_struct
*tty
, int exit_session
)
565 struct file
*cons_filp
= NULL
;
566 struct file
*filp
, *f
= NULL
;
567 struct tty_file_private
*priv
;
568 int closecount
= 0, n
;
575 spin_lock(&redirect_lock
);
576 if (redirect
&& file_tty(redirect
) == tty
) {
580 spin_unlock(&redirect_lock
);
584 if (test_bit(TTY_HUPPED
, &tty
->flags
)) {
589 /* inuse_filps is protected by the single tty lock,
590 this really needs to change if we want to flush the
591 workqueue with the lock held */
592 check_tty_count(tty
, "tty_hangup");
594 spin_lock(&tty
->files_lock
);
595 /* This breaks for file handles being sent over AF_UNIX sockets ? */
596 list_for_each_entry(priv
, &tty
->tty_files
, list
) {
598 if (filp
->f_op
->write
== redirected_tty_write
)
600 if (filp
->f_op
->write
!= tty_write
)
603 __tty_fasync(-1, filp
, 0); /* can't block */
604 filp
->f_op
= &hung_up_tty_fops
;
606 spin_unlock(&tty
->files_lock
);
608 refs
= tty_signal_session_leader(tty
, exit_session
);
609 /* Account for the p->signal references we killed */
613 tty_ldisc_hangup(tty
, cons_filp
!= NULL
);
615 spin_lock_irq(&tty
->ctrl_lock
);
616 clear_bit(TTY_THROTTLED
, &tty
->flags
);
617 clear_bit(TTY_DO_WRITE_WAKEUP
, &tty
->flags
);
618 put_pid(tty
->session
);
622 tty
->ctrl_status
= 0;
623 spin_unlock_irq(&tty
->ctrl_lock
);
626 * If one of the devices matches a console pointer, we
627 * cannot just call hangup() because that will cause
628 * tty->count and state->count to go out of sync.
629 * So we just call close() the right number of times.
633 for (n
= 0; n
< closecount
; n
++)
634 tty
->ops
->close(tty
, cons_filp
);
635 } else if (tty
->ops
->hangup
)
636 tty
->ops
->hangup(tty
);
638 * We don't want to have driver/ldisc interactions beyond the ones
639 * we did here. The driver layer expects no calls after ->hangup()
640 * from the ldisc side, which is now guaranteed.
642 set_bit(TTY_HUPPED
, &tty
->flags
);
649 static void do_tty_hangup(struct work_struct
*work
)
651 struct tty_struct
*tty
=
652 container_of(work
, struct tty_struct
, hangup_work
);
654 __tty_hangup(tty
, 0);
658 * tty_hangup - trigger a hangup event
659 * @tty: tty to hangup
661 * A carrier loss (virtual or otherwise) has occurred on this like
662 * schedule a hangup sequence to run after this event.
665 void tty_hangup(struct tty_struct
*tty
)
667 tty_debug_hangup(tty
, "hangup\n");
668 schedule_work(&tty
->hangup_work
);
671 EXPORT_SYMBOL(tty_hangup
);
674 * tty_vhangup - process vhangup
675 * @tty: tty to hangup
677 * The user has asked via system call for the terminal to be hung up.
678 * We do this synchronously so that when the syscall returns the process
679 * is complete. That guarantee is necessary for security reasons.
682 void tty_vhangup(struct tty_struct
*tty
)
684 tty_debug_hangup(tty
, "vhangup\n");
685 __tty_hangup(tty
, 0);
688 EXPORT_SYMBOL(tty_vhangup
);
692 * tty_vhangup_self - process vhangup for own ctty
694 * Perform a vhangup on the current controlling tty
697 void tty_vhangup_self(void)
699 struct tty_struct
*tty
;
701 tty
= get_current_tty();
709 * tty_vhangup_session - hangup session leader exit
710 * @tty: tty to hangup
712 * The session leader is exiting and hanging up its controlling terminal.
713 * Every process in the foreground process group is signalled SIGHUP.
715 * We do this synchronously so that when the syscall returns the process
716 * is complete. That guarantee is necessary for security reasons.
719 void tty_vhangup_session(struct tty_struct
*tty
)
721 tty_debug_hangup(tty
, "session hangup\n");
722 __tty_hangup(tty
, 1);
726 * tty_hung_up_p - was tty hung up
727 * @filp: file pointer of tty
729 * Return true if the tty has been subject to a vhangup or a carrier
733 int tty_hung_up_p(struct file
*filp
)
735 return (filp
&& filp
->f_op
== &hung_up_tty_fops
);
738 EXPORT_SYMBOL(tty_hung_up_p
);
741 * stop_tty - propagate flow control
744 * Perform flow control to the driver. May be called
745 * on an already stopped device and will not re-call the driver
748 * This functionality is used by both the line disciplines for
749 * halting incoming flow and by the driver. It may therefore be
750 * called from any context, may be under the tty atomic_write_lock
757 void __stop_tty(struct tty_struct
*tty
)
766 void stop_tty(struct tty_struct
*tty
)
770 spin_lock_irqsave(&tty
->flow_lock
, flags
);
772 spin_unlock_irqrestore(&tty
->flow_lock
, flags
);
774 EXPORT_SYMBOL(stop_tty
);
777 * start_tty - propagate flow control
780 * Start a tty that has been stopped if at all possible. If this
781 * tty was previous stopped and is now being started, the driver
782 * start method is invoked and the line discipline woken.
788 void __start_tty(struct tty_struct
*tty
)
790 if (!tty
->stopped
|| tty
->flow_stopped
)
794 tty
->ops
->start(tty
);
798 void start_tty(struct tty_struct
*tty
)
802 spin_lock_irqsave(&tty
->flow_lock
, flags
);
804 spin_unlock_irqrestore(&tty
->flow_lock
, flags
);
806 EXPORT_SYMBOL(start_tty
);
808 static void tty_update_time(struct timespec
*time
)
810 unsigned long sec
= get_seconds();
813 * We only care if the two values differ in anything other than the
814 * lower three bits (i.e every 8 seconds). If so, then we can update
815 * the time of the tty device, otherwise it could be construded as a
816 * security leak to let userspace know the exact timing of the tty.
818 if ((sec
^ time
->tv_sec
) & ~7)
823 * tty_read - read method for tty device files
824 * @file: pointer to tty file
826 * @count: size of user buffer
829 * Perform the read system call function on this terminal device. Checks
830 * for hung up devices before calling the line discipline method.
833 * Locks the line discipline internally while needed. Multiple
834 * read calls may be outstanding in parallel.
837 static ssize_t
tty_read(struct file
*file
, char __user
*buf
, size_t count
,
841 struct inode
*inode
= file_inode(file
);
842 struct tty_struct
*tty
= file_tty(file
);
843 struct tty_ldisc
*ld
;
845 if (tty_paranoia_check(tty
, inode
, "tty_read"))
847 if (!tty
|| tty_io_error(tty
))
850 /* We want to wait for the line discipline to sort out in this
852 ld
= tty_ldisc_ref_wait(tty
);
854 return hung_up_tty_read(file
, buf
, count
, ppos
);
856 i
= ld
->ops
->read(tty
, file
, buf
, count
);
862 tty_update_time(&inode
->i_atime
);
867 static void tty_write_unlock(struct tty_struct
*tty
)
869 mutex_unlock(&tty
->atomic_write_lock
);
870 wake_up_interruptible_poll(&tty
->write_wait
, POLLOUT
);
873 static int tty_write_lock(struct tty_struct
*tty
, int ndelay
)
875 if (!mutex_trylock(&tty
->atomic_write_lock
)) {
878 if (mutex_lock_interruptible(&tty
->atomic_write_lock
))
885 * Split writes up in sane blocksizes to avoid
886 * denial-of-service type attacks
888 static inline ssize_t
do_tty_write(
889 ssize_t (*write
)(struct tty_struct
*, struct file
*, const unsigned char *, size_t),
890 struct tty_struct
*tty
,
892 const char __user
*buf
,
895 ssize_t ret
, written
= 0;
898 ret
= tty_write_lock(tty
, file
->f_flags
& O_NDELAY
);
903 * We chunk up writes into a temporary buffer. This
904 * simplifies low-level drivers immensely, since they
905 * don't have locking issues and user mode accesses.
907 * But if TTY_NO_WRITE_SPLIT is set, we should use a
910 * The default chunk-size is 2kB, because the NTTY
911 * layer has problems with bigger chunks. It will
912 * claim to be able to handle more characters than
915 * FIXME: This can probably go away now except that 64K chunks
916 * are too likely to fail unless switched to vmalloc...
919 if (test_bit(TTY_NO_WRITE_SPLIT
, &tty
->flags
))
924 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
925 if (tty
->write_cnt
< chunk
) {
926 unsigned char *buf_chunk
;
931 buf_chunk
= kmalloc(chunk
, GFP_KERNEL
);
936 kfree(tty
->write_buf
);
937 tty
->write_cnt
= chunk
;
938 tty
->write_buf
= buf_chunk
;
941 /* Do the write .. */
947 if (copy_from_user(tty
->write_buf
, buf
, size
))
949 ret
= write(tty
, file
, tty
->write_buf
, size
);
958 if (signal_pending(current
))
963 tty_update_time(&file_inode(file
)->i_mtime
);
967 tty_write_unlock(tty
);
972 * tty_write_message - write a message to a certain tty, not just the console.
973 * @tty: the destination tty_struct
974 * @msg: the message to write
976 * This is used for messages that need to be redirected to a specific tty.
977 * We don't put it into the syslog queue right now maybe in the future if
980 * We must still hold the BTM and test the CLOSING flag for the moment.
983 void tty_write_message(struct tty_struct
*tty
, char *msg
)
986 mutex_lock(&tty
->atomic_write_lock
);
988 if (tty
->ops
->write
&& tty
->count
> 0)
989 tty
->ops
->write(tty
, msg
, strlen(msg
));
991 tty_write_unlock(tty
);
998 * tty_write - write method for tty device file
999 * @file: tty file pointer
1000 * @buf: user data to write
1001 * @count: bytes to write
1004 * Write data to a tty device via the line discipline.
1007 * Locks the line discipline as required
1008 * Writes to the tty driver are serialized by the atomic_write_lock
1009 * and are then processed in chunks to the device. The line discipline
1010 * write method will not be invoked in parallel for each device.
1013 static ssize_t
tty_write(struct file
*file
, const char __user
*buf
,
1014 size_t count
, loff_t
*ppos
)
1016 struct tty_struct
*tty
= file_tty(file
);
1017 struct tty_ldisc
*ld
;
1020 if (tty_paranoia_check(tty
, file_inode(file
), "tty_write"))
1022 if (!tty
|| !tty
->ops
->write
|| tty_io_error(tty
))
1024 /* Short term debug to catch buggy drivers */
1025 if (tty
->ops
->write_room
== NULL
)
1026 tty_err(tty
, "missing write_room method\n");
1027 ld
= tty_ldisc_ref_wait(tty
);
1029 return hung_up_tty_write(file
, buf
, count
, ppos
);
1030 if (!ld
->ops
->write
)
1033 ret
= do_tty_write(ld
->ops
->write
, tty
, file
, buf
, count
);
1034 tty_ldisc_deref(ld
);
1038 ssize_t
redirected_tty_write(struct file
*file
, const char __user
*buf
,
1039 size_t count
, loff_t
*ppos
)
1041 struct file
*p
= NULL
;
1043 spin_lock(&redirect_lock
);
1045 p
= get_file(redirect
);
1046 spin_unlock(&redirect_lock
);
1050 res
= vfs_write(p
, buf
, count
, &p
->f_pos
);
1054 return tty_write(file
, buf
, count
, ppos
);
1058 * tty_send_xchar - send priority character
1060 * Send a high priority character to the tty even if stopped
1062 * Locking: none for xchar method, write ordering for write method.
1065 int tty_send_xchar(struct tty_struct
*tty
, char ch
)
1067 int was_stopped
= tty
->stopped
;
1069 if (tty
->ops
->send_xchar
) {
1070 down_read(&tty
->termios_rwsem
);
1071 tty
->ops
->send_xchar(tty
, ch
);
1072 up_read(&tty
->termios_rwsem
);
1076 if (tty_write_lock(tty
, 0) < 0)
1077 return -ERESTARTSYS
;
1079 down_read(&tty
->termios_rwsem
);
1082 tty
->ops
->write(tty
, &ch
, 1);
1085 up_read(&tty
->termios_rwsem
);
1086 tty_write_unlock(tty
);
1090 static char ptychar
[] = "pqrstuvwxyzabcde";
1093 * pty_line_name - generate name for a pty
1094 * @driver: the tty driver in use
1095 * @index: the minor number
1096 * @p: output buffer of at least 6 bytes
1098 * Generate a name from a driver reference and write it to the output
1103 static void pty_line_name(struct tty_driver
*driver
, int index
, char *p
)
1105 int i
= index
+ driver
->name_base
;
1106 /* ->name is initialized to "ttyp", but "tty" is expected */
1107 sprintf(p
, "%s%c%x",
1108 driver
->subtype
== PTY_TYPE_SLAVE
? "tty" : driver
->name
,
1109 ptychar
[i
>> 4 & 0xf], i
& 0xf);
1113 * tty_line_name - generate name for a tty
1114 * @driver: the tty driver in use
1115 * @index: the minor number
1116 * @p: output buffer of at least 7 bytes
1118 * Generate a name from a driver reference and write it to the output
1123 static ssize_t
tty_line_name(struct tty_driver
*driver
, int index
, char *p
)
1125 if (driver
->flags
& TTY_DRIVER_UNNUMBERED_NODE
)
1126 return sprintf(p
, "%s", driver
->name
);
1128 return sprintf(p
, "%s%d", driver
->name
,
1129 index
+ driver
->name_base
);
1133 * tty_driver_lookup_tty() - find an existing tty, if any
1134 * @driver: the driver for the tty
1135 * @idx: the minor number
1137 * Return the tty, if found. If not found, return NULL or ERR_PTR() if the
1138 * driver lookup() method returns an error.
1140 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1142 static struct tty_struct
*tty_driver_lookup_tty(struct tty_driver
*driver
,
1143 struct file
*file
, int idx
)
1145 struct tty_struct
*tty
;
1147 if (driver
->ops
->lookup
)
1149 tty
= ERR_PTR(-EIO
);
1151 tty
= driver
->ops
->lookup(driver
, file
, idx
);
1153 tty
= driver
->ttys
[idx
];
1161 * tty_init_termios - helper for termios setup
1162 * @tty: the tty to set up
1164 * Initialise the termios structures for this tty. Thus runs under
1165 * the tty_mutex currently so we can be relaxed about ordering.
1168 void tty_init_termios(struct tty_struct
*tty
)
1170 struct ktermios
*tp
;
1171 int idx
= tty
->index
;
1173 if (tty
->driver
->flags
& TTY_DRIVER_RESET_TERMIOS
)
1174 tty
->termios
= tty
->driver
->init_termios
;
1176 /* Check for lazy saved data */
1177 tp
= tty
->driver
->termios
[idx
];
1180 tty
->termios
.c_line
= tty
->driver
->init_termios
.c_line
;
1182 tty
->termios
= tty
->driver
->init_termios
;
1184 /* Compatibility until drivers always set this */
1185 tty
->termios
.c_ispeed
= tty_termios_input_baud_rate(&tty
->termios
);
1186 tty
->termios
.c_ospeed
= tty_termios_baud_rate(&tty
->termios
);
1188 EXPORT_SYMBOL_GPL(tty_init_termios
);
1190 int tty_standard_install(struct tty_driver
*driver
, struct tty_struct
*tty
)
1192 tty_init_termios(tty
);
1193 tty_driver_kref_get(driver
);
1195 driver
->ttys
[tty
->index
] = tty
;
1198 EXPORT_SYMBOL_GPL(tty_standard_install
);
1201 * tty_driver_install_tty() - install a tty entry in the driver
1202 * @driver: the driver for the tty
1205 * Install a tty object into the driver tables. The tty->index field
1206 * will be set by the time this is called. This method is responsible
1207 * for ensuring any need additional structures are allocated and
1210 * Locking: tty_mutex for now
1212 static int tty_driver_install_tty(struct tty_driver
*driver
,
1213 struct tty_struct
*tty
)
1215 return driver
->ops
->install
? driver
->ops
->install(driver
, tty
) :
1216 tty_standard_install(driver
, tty
);
1220 * tty_driver_remove_tty() - remove a tty from the driver tables
1221 * @driver: the driver for the tty
1222 * @idx: the minor number
1224 * Remvoe a tty object from the driver tables. The tty->index field
1225 * will be set by the time this is called.
1227 * Locking: tty_mutex for now
1229 static void tty_driver_remove_tty(struct tty_driver
*driver
, struct tty_struct
*tty
)
1231 if (driver
->ops
->remove
)
1232 driver
->ops
->remove(driver
, tty
);
1234 driver
->ttys
[tty
->index
] = NULL
;
1238 * tty_reopen() - fast re-open of an open tty
1239 * @tty - the tty to open
1241 * Return 0 on success, -errno on error.
1242 * Re-opens on master ptys are not allowed and return -EIO.
1244 * Locking: Caller must hold tty_lock
1246 static int tty_reopen(struct tty_struct
*tty
)
1248 struct tty_driver
*driver
= tty
->driver
;
1250 if (driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1251 driver
->subtype
== PTY_TYPE_MASTER
)
1257 if (test_bit(TTY_EXCLUSIVE
, &tty
->flags
) && !capable(CAP_SYS_ADMIN
))
1263 return tty_ldisc_reinit(tty
, tty
->termios
.c_line
);
1269 * tty_init_dev - initialise a tty device
1270 * @driver: tty driver we are opening a device on
1271 * @idx: device index
1272 * @ret_tty: returned tty structure
1274 * Prepare a tty device. This may not be a "new" clean device but
1275 * could also be an active device. The pty drivers require special
1276 * handling because of this.
1279 * The function is called under the tty_mutex, which
1280 * protects us from the tty struct or driver itself going away.
1282 * On exit the tty device has the line discipline attached and
1283 * a reference count of 1. If a pair was created for pty/tty use
1284 * and the other was a pty master then it too has a reference count of 1.
1286 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1287 * failed open. The new code protects the open with a mutex, so it's
1288 * really quite straightforward. The mutex locking can probably be
1289 * relaxed for the (most common) case of reopening a tty.
1292 struct tty_struct
*tty_init_dev(struct tty_driver
*driver
, int idx
)
1294 struct tty_struct
*tty
;
1298 * First time open is complex, especially for PTY devices.
1299 * This code guarantees that either everything succeeds and the
1300 * TTY is ready for operation, or else the table slots are vacated
1301 * and the allocated memory released. (Except that the termios
1305 if (!try_module_get(driver
->owner
))
1306 return ERR_PTR(-ENODEV
);
1308 tty
= alloc_tty_struct(driver
, idx
);
1311 goto err_module_put
;
1315 retval
= tty_driver_install_tty(driver
, tty
);
1320 tty
->port
= driver
->ports
[idx
];
1322 WARN_RATELIMIT(!tty
->port
,
1323 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1324 __func__
, tty
->driver
->name
);
1326 retval
= tty_ldisc_lock(tty
, 5 * HZ
);
1328 goto err_release_lock
;
1329 tty
->port
->itty
= tty
;
1332 * Structures all installed ... call the ldisc open routines.
1333 * If we fail here just call release_tty to clean up. No need
1334 * to decrement the use counts, as release_tty doesn't care.
1336 retval
= tty_ldisc_setup(tty
, tty
->link
);
1338 goto err_release_tty
;
1339 tty_ldisc_unlock(tty
);
1340 /* Return the tty locked so that it cannot vanish under the caller */
1345 free_tty_struct(tty
);
1347 module_put(driver
->owner
);
1348 return ERR_PTR(retval
);
1350 /* call the tty release_tty routine to clean out this slot */
1352 tty_ldisc_unlock(tty
);
1353 tty_info_ratelimited(tty
, "ldisc open failed (%d), clearing slot %d\n",
1357 release_tty(tty
, idx
);
1358 return ERR_PTR(retval
);
1361 static void tty_free_termios(struct tty_struct
*tty
)
1363 struct ktermios
*tp
;
1364 int idx
= tty
->index
;
1366 /* If the port is going to reset then it has no termios to save */
1367 if (tty
->driver
->flags
& TTY_DRIVER_RESET_TERMIOS
)
1370 /* Stash the termios data */
1371 tp
= tty
->driver
->termios
[idx
];
1373 tp
= kmalloc(sizeof(struct ktermios
), GFP_KERNEL
);
1376 tty
->driver
->termios
[idx
] = tp
;
1382 * tty_flush_works - flush all works of a tty/pty pair
1383 * @tty: tty device to flush works for (or either end of a pty pair)
1385 * Sync flush all works belonging to @tty (and the 'other' tty).
1387 static void tty_flush_works(struct tty_struct
*tty
)
1389 flush_work(&tty
->SAK_work
);
1390 flush_work(&tty
->hangup_work
);
1392 flush_work(&tty
->link
->SAK_work
);
1393 flush_work(&tty
->link
->hangup_work
);
1398 * release_one_tty - release tty structure memory
1399 * @kref: kref of tty we are obliterating
1401 * Releases memory associated with a tty structure, and clears out the
1402 * driver table slots. This function is called when a device is no longer
1403 * in use. It also gets called when setup of a device fails.
1406 * takes the file list lock internally when working on the list
1407 * of ttys that the driver keeps.
1409 * This method gets called from a work queue so that the driver private
1410 * cleanup ops can sleep (needed for USB at least)
1412 static void release_one_tty(struct work_struct
*work
)
1414 struct tty_struct
*tty
=
1415 container_of(work
, struct tty_struct
, hangup_work
);
1416 struct tty_driver
*driver
= tty
->driver
;
1417 struct module
*owner
= driver
->owner
;
1419 if (tty
->ops
->cleanup
)
1420 tty
->ops
->cleanup(tty
);
1423 tty_driver_kref_put(driver
);
1426 spin_lock(&tty
->files_lock
);
1427 list_del_init(&tty
->tty_files
);
1428 spin_unlock(&tty
->files_lock
);
1431 put_pid(tty
->session
);
1432 free_tty_struct(tty
);
1435 static void queue_release_one_tty(struct kref
*kref
)
1437 struct tty_struct
*tty
= container_of(kref
, struct tty_struct
, kref
);
1439 /* The hangup queue is now free so we can reuse it rather than
1440 waste a chunk of memory for each port */
1441 INIT_WORK(&tty
->hangup_work
, release_one_tty
);
1442 schedule_work(&tty
->hangup_work
);
1446 * tty_kref_put - release a tty kref
1449 * Release a reference to a tty device and if need be let the kref
1450 * layer destruct the object for us
1453 void tty_kref_put(struct tty_struct
*tty
)
1456 kref_put(&tty
->kref
, queue_release_one_tty
);
1458 EXPORT_SYMBOL(tty_kref_put
);
1461 * release_tty - release tty structure memory
1463 * Release both @tty and a possible linked partner (think pty pair),
1464 * and decrement the refcount of the backing module.
1468 * takes the file list lock internally when working on the list
1469 * of ttys that the driver keeps.
1472 static void release_tty(struct tty_struct
*tty
, int idx
)
1474 /* This should always be true but check for the moment */
1475 WARN_ON(tty
->index
!= idx
);
1476 WARN_ON(!mutex_is_locked(&tty_mutex
));
1477 if (tty
->ops
->shutdown
)
1478 tty
->ops
->shutdown(tty
);
1479 tty_free_termios(tty
);
1480 tty_driver_remove_tty(tty
->driver
, tty
);
1481 tty
->port
->itty
= NULL
;
1483 tty
->link
->port
->itty
= NULL
;
1484 tty_buffer_cancel_work(tty
->port
);
1486 tty_kref_put(tty
->link
);
1491 * tty_release_checks - check a tty before real release
1492 * @tty: tty to check
1493 * @o_tty: link of @tty (if any)
1494 * @idx: index of the tty
1496 * Performs some paranoid checking before true release of the @tty.
1497 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1499 static int tty_release_checks(struct tty_struct
*tty
, int idx
)
1501 #ifdef TTY_PARANOIA_CHECK
1502 if (idx
< 0 || idx
>= tty
->driver
->num
) {
1503 tty_debug(tty
, "bad idx %d\n", idx
);
1507 /* not much to check for devpts */
1508 if (tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
)
1511 if (tty
!= tty
->driver
->ttys
[idx
]) {
1512 tty_debug(tty
, "bad driver table[%d] = %p\n",
1513 idx
, tty
->driver
->ttys
[idx
]);
1516 if (tty
->driver
->other
) {
1517 struct tty_struct
*o_tty
= tty
->link
;
1519 if (o_tty
!= tty
->driver
->other
->ttys
[idx
]) {
1520 tty_debug(tty
, "bad other table[%d] = %p\n",
1521 idx
, tty
->driver
->other
->ttys
[idx
]);
1524 if (o_tty
->link
!= tty
) {
1525 tty_debug(tty
, "bad link = %p\n", o_tty
->link
);
1534 * tty_kclose - closes tty opened by tty_kopen
1537 * Performs the final steps to release and free a tty device. It is the
1538 * same as tty_release_struct except that it also resets TTY_PORT_KOPENED
1539 * flag on tty->port.
1541 void tty_kclose(struct tty_struct
*tty
)
1544 * Ask the line discipline code to release its structures
1546 tty_ldisc_release(tty
);
1548 /* Wait for pending work before tty destruction commmences */
1549 tty_flush_works(tty
);
1551 tty_debug_hangup(tty
, "freeing structure\n");
1553 * The release_tty function takes care of the details of clearing
1554 * the slots and preserving the termios structure. The tty_unlock_pair
1555 * should be safe as we keep a kref while the tty is locked (so the
1556 * unlock never unlocks a freed tty).
1558 mutex_lock(&tty_mutex
);
1559 tty_port_set_kopened(tty
->port
, 0);
1560 release_tty(tty
, tty
->index
);
1561 mutex_unlock(&tty_mutex
);
1563 EXPORT_SYMBOL_GPL(tty_kclose
);
1566 * tty_release_struct - release a tty struct
1568 * @idx: index of the tty
1570 * Performs the final steps to release and free a tty device. It is
1571 * roughly the reverse of tty_init_dev.
1573 void tty_release_struct(struct tty_struct
*tty
, int idx
)
1576 * Ask the line discipline code to release its structures
1578 tty_ldisc_release(tty
);
1580 /* Wait for pending work before tty destruction commmences */
1581 tty_flush_works(tty
);
1583 tty_debug_hangup(tty
, "freeing structure\n");
1585 * The release_tty function takes care of the details of clearing
1586 * the slots and preserving the termios structure. The tty_unlock_pair
1587 * should be safe as we keep a kref while the tty is locked (so the
1588 * unlock never unlocks a freed tty).
1590 mutex_lock(&tty_mutex
);
1591 release_tty(tty
, idx
);
1592 mutex_unlock(&tty_mutex
);
1594 EXPORT_SYMBOL_GPL(tty_release_struct
);
1597 * tty_release - vfs callback for close
1598 * @inode: inode of tty
1599 * @filp: file pointer for handle to tty
1601 * Called the last time each file handle is closed that references
1602 * this tty. There may however be several such references.
1605 * Takes bkl. See tty_release_dev
1607 * Even releasing the tty structures is a tricky business.. We have
1608 * to be very careful that the structures are all released at the
1609 * same time, as interrupts might otherwise get the wrong pointers.
1611 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1612 * lead to double frees or releasing memory still in use.
1615 int tty_release(struct inode
*inode
, struct file
*filp
)
1617 struct tty_struct
*tty
= file_tty(filp
);
1618 struct tty_struct
*o_tty
= NULL
;
1619 int do_sleep
, final
;
1624 if (tty_paranoia_check(tty
, inode
, __func__
))
1628 check_tty_count(tty
, __func__
);
1630 __tty_fasync(-1, filp
, 0);
1633 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1634 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
1637 if (tty_release_checks(tty
, idx
)) {
1642 tty_debug_hangup(tty
, "releasing (count=%d)\n", tty
->count
);
1644 if (tty
->ops
->close
)
1645 tty
->ops
->close(tty
, filp
);
1647 /* If tty is pty master, lock the slave pty (stable lock order) */
1648 tty_lock_slave(o_tty
);
1651 * Sanity check: if tty->count is going to zero, there shouldn't be
1652 * any waiters on tty->read_wait or tty->write_wait. We test the
1653 * wait queues and kick everyone out _before_ actually starting to
1654 * close. This ensures that we won't block while releasing the tty
1657 * The test for the o_tty closing is necessary, since the master and
1658 * slave sides may close in any order. If the slave side closes out
1659 * first, its count will be one, since the master side holds an open.
1660 * Thus this test wouldn't be triggered at the time the slave closed,
1666 if (tty
->count
<= 1) {
1667 if (waitqueue_active(&tty
->read_wait
)) {
1668 wake_up_poll(&tty
->read_wait
, POLLIN
);
1671 if (waitqueue_active(&tty
->write_wait
)) {
1672 wake_up_poll(&tty
->write_wait
, POLLOUT
);
1676 if (o_tty
&& o_tty
->count
<= 1) {
1677 if (waitqueue_active(&o_tty
->read_wait
)) {
1678 wake_up_poll(&o_tty
->read_wait
, POLLIN
);
1681 if (waitqueue_active(&o_tty
->write_wait
)) {
1682 wake_up_poll(&o_tty
->write_wait
, POLLOUT
);
1691 tty_warn(tty
, "read/write wait queue active!\n");
1693 schedule_timeout_killable(timeout
);
1694 if (timeout
< 120 * HZ
)
1695 timeout
= 2 * timeout
+ 1;
1697 timeout
= MAX_SCHEDULE_TIMEOUT
;
1701 if (--o_tty
->count
< 0) {
1702 tty_warn(tty
, "bad slave count (%d)\n", o_tty
->count
);
1706 if (--tty
->count
< 0) {
1707 tty_warn(tty
, "bad tty->count (%d)\n", tty
->count
);
1712 * We've decremented tty->count, so we need to remove this file
1713 * descriptor off the tty->tty_files list; this serves two
1715 * - check_tty_count sees the correct number of file descriptors
1716 * associated with this tty.
1717 * - do_tty_hangup no longer sees this file descriptor as
1718 * something that needs to be handled for hangups.
1723 * Perform some housekeeping before deciding whether to return.
1725 * If _either_ side is closing, make sure there aren't any
1726 * processes that still think tty or o_tty is their controlling
1730 read_lock(&tasklist_lock
);
1731 session_clear_tty(tty
->session
);
1733 session_clear_tty(o_tty
->session
);
1734 read_unlock(&tasklist_lock
);
1737 /* check whether both sides are closing ... */
1738 final
= !tty
->count
&& !(o_tty
&& o_tty
->count
);
1740 tty_unlock_slave(o_tty
);
1743 /* At this point, the tty->count == 0 should ensure a dead tty
1744 cannot be re-opened by a racing opener */
1749 tty_debug_hangup(tty
, "final close\n");
1751 tty_release_struct(tty
, idx
);
1756 * tty_open_current_tty - get locked tty of current task
1757 * @device: device number
1758 * @filp: file pointer to tty
1759 * @return: locked tty of the current task iff @device is /dev/tty
1761 * Performs a re-open of the current task's controlling tty.
1763 * We cannot return driver and index like for the other nodes because
1764 * devpts will not work then. It expects inodes to be from devpts FS.
1766 static struct tty_struct
*tty_open_current_tty(dev_t device
, struct file
*filp
)
1768 struct tty_struct
*tty
;
1771 if (device
!= MKDEV(TTYAUX_MAJOR
, 0))
1774 tty
= get_current_tty();
1776 return ERR_PTR(-ENXIO
);
1778 filp
->f_flags
|= O_NONBLOCK
; /* Don't let /dev/tty block */
1781 tty_kref_put(tty
); /* safe to drop the kref now */
1783 retval
= tty_reopen(tty
);
1786 tty
= ERR_PTR(retval
);
1792 * tty_lookup_driver - lookup a tty driver for a given device file
1793 * @device: device number
1794 * @filp: file pointer to tty
1795 * @index: index for the device in the @return driver
1796 * @return: driver for this inode (with increased refcount)
1798 * If @return is not erroneous, the caller is responsible to decrement the
1799 * refcount by tty_driver_kref_put.
1801 * Locking: tty_mutex protects get_tty_driver
1803 static struct tty_driver
*tty_lookup_driver(dev_t device
, struct file
*filp
,
1806 struct tty_driver
*driver
;
1810 case MKDEV(TTY_MAJOR
, 0): {
1811 extern struct tty_driver
*console_driver
;
1812 driver
= tty_driver_kref_get(console_driver
);
1813 *index
= fg_console
;
1817 case MKDEV(TTYAUX_MAJOR
, 1): {
1818 struct tty_driver
*console_driver
= console_device(index
);
1819 if (console_driver
) {
1820 driver
= tty_driver_kref_get(console_driver
);
1821 if (driver
&& filp
) {
1822 /* Don't let /dev/console block */
1823 filp
->f_flags
|= O_NONBLOCK
;
1827 return ERR_PTR(-ENODEV
);
1830 driver
= get_tty_driver(device
, index
);
1832 return ERR_PTR(-ENODEV
);
1839 * tty_kopen - open a tty device for kernel
1840 * @device: dev_t of device to open
1842 * Opens tty exclusively for kernel. Performs the driver lookup,
1843 * makes sure it's not already opened and performs the first-time
1844 * tty initialization.
1846 * Returns the locked initialized &tty_struct
1848 * Claims the global tty_mutex to serialize:
1849 * - concurrent first-time tty initialization
1850 * - concurrent tty driver removal w/ lookup
1851 * - concurrent tty removal from driver table
1853 struct tty_struct
*tty_kopen(dev_t device
)
1855 struct tty_struct
*tty
;
1856 struct tty_driver
*driver
= NULL
;
1859 mutex_lock(&tty_mutex
);
1860 driver
= tty_lookup_driver(device
, NULL
, &index
);
1861 if (IS_ERR(driver
)) {
1862 mutex_unlock(&tty_mutex
);
1863 return ERR_CAST(driver
);
1866 /* check whether we're reopening an existing tty */
1867 tty
= tty_driver_lookup_tty(driver
, NULL
, index
);
1872 /* drop kref from tty_driver_lookup_tty() */
1874 tty
= ERR_PTR(-EBUSY
);
1875 } else { /* tty_init_dev returns tty with the tty_lock held */
1876 tty
= tty_init_dev(driver
, index
);
1879 tty_port_set_kopened(tty
->port
, 1);
1882 mutex_unlock(&tty_mutex
);
1883 tty_driver_kref_put(driver
);
1886 EXPORT_SYMBOL_GPL(tty_kopen
);
1889 * tty_open_by_driver - open a tty device
1890 * @device: dev_t of device to open
1891 * @inode: inode of device file
1892 * @filp: file pointer to tty
1894 * Performs the driver lookup, checks for a reopen, or otherwise
1895 * performs the first-time tty initialization.
1897 * Returns the locked initialized or re-opened &tty_struct
1899 * Claims the global tty_mutex to serialize:
1900 * - concurrent first-time tty initialization
1901 * - concurrent tty driver removal w/ lookup
1902 * - concurrent tty removal from driver table
1904 static struct tty_struct
*tty_open_by_driver(dev_t device
, struct inode
*inode
,
1907 struct tty_struct
*tty
;
1908 struct tty_driver
*driver
= NULL
;
1912 mutex_lock(&tty_mutex
);
1913 driver
= tty_lookup_driver(device
, filp
, &index
);
1914 if (IS_ERR(driver
)) {
1915 mutex_unlock(&tty_mutex
);
1916 return ERR_CAST(driver
);
1919 /* check whether we're reopening an existing tty */
1920 tty
= tty_driver_lookup_tty(driver
, filp
, index
);
1922 mutex_unlock(&tty_mutex
);
1927 if (tty_port_kopened(tty
->port
)) {
1929 mutex_unlock(&tty_mutex
);
1930 tty
= ERR_PTR(-EBUSY
);
1933 mutex_unlock(&tty_mutex
);
1934 retval
= tty_lock_interruptible(tty
);
1935 tty_kref_put(tty
); /* drop kref from tty_driver_lookup_tty() */
1937 if (retval
== -EINTR
)
1938 retval
= -ERESTARTSYS
;
1939 tty
= ERR_PTR(retval
);
1942 retval
= tty_reopen(tty
);
1945 tty
= ERR_PTR(retval
);
1947 } else { /* Returns with the tty_lock held for now */
1948 tty
= tty_init_dev(driver
, index
);
1949 mutex_unlock(&tty_mutex
);
1952 tty_driver_kref_put(driver
);
1957 * tty_open - open a tty device
1958 * @inode: inode of device file
1959 * @filp: file pointer to tty
1961 * tty_open and tty_release keep up the tty count that contains the
1962 * number of opens done on a tty. We cannot use the inode-count, as
1963 * different inodes might point to the same tty.
1965 * Open-counting is needed for pty masters, as well as for keeping
1966 * track of serial lines: DTR is dropped when the last close happens.
1967 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1969 * The termios state of a pty is reset on first open so that
1970 * settings don't persist across reuse.
1972 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
1973 * tty->count should protect the rest.
1974 * ->siglock protects ->signal/->sighand
1976 * Note: the tty_unlock/lock cases without a ref are only safe due to
1980 static int tty_open(struct inode
*inode
, struct file
*filp
)
1982 struct tty_struct
*tty
;
1984 dev_t device
= inode
->i_rdev
;
1985 unsigned saved_flags
= filp
->f_flags
;
1987 nonseekable_open(inode
, filp
);
1990 retval
= tty_alloc_file(filp
);
1994 tty
= tty_open_current_tty(device
, filp
);
1996 tty
= tty_open_by_driver(device
, inode
, filp
);
1999 tty_free_file(filp
);
2000 retval
= PTR_ERR(tty
);
2001 if (retval
!= -EAGAIN
|| signal_pending(current
))
2007 tty_add_file(tty
, filp
);
2009 check_tty_count(tty
, __func__
);
2010 tty_debug_hangup(tty
, "opening (count=%d)\n", tty
->count
);
2013 retval
= tty
->ops
->open(tty
, filp
);
2016 filp
->f_flags
= saved_flags
;
2019 tty_debug_hangup(tty
, "open error %d, releasing\n", retval
);
2021 tty_unlock(tty
); /* need to call tty_release without BTM */
2022 tty_release(inode
, filp
);
2023 if (retval
!= -ERESTARTSYS
)
2026 if (signal_pending(current
))
2031 * Need to reset f_op in case a hangup happened.
2033 if (tty_hung_up_p(filp
))
2034 filp
->f_op
= &tty_fops
;
2037 clear_bit(TTY_HUPPED
, &tty
->flags
);
2039 noctty
= (filp
->f_flags
& O_NOCTTY
) ||
2040 (IS_ENABLED(CONFIG_VT
) && device
== MKDEV(TTY_MAJOR
, 0)) ||
2041 device
== MKDEV(TTYAUX_MAJOR
, 1) ||
2042 (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2043 tty
->driver
->subtype
== PTY_TYPE_MASTER
);
2045 tty_open_proc_set_tty(filp
, tty
);
2053 * tty_poll - check tty status
2054 * @filp: file being polled
2055 * @wait: poll wait structures to update
2057 * Call the line discipline polling method to obtain the poll
2058 * status of the device.
2060 * Locking: locks called line discipline but ldisc poll method
2061 * may be re-entered freely by other callers.
2064 static unsigned int tty_poll(struct file
*filp
, poll_table
*wait
)
2066 struct tty_struct
*tty
= file_tty(filp
);
2067 struct tty_ldisc
*ld
;
2070 if (tty_paranoia_check(tty
, file_inode(filp
), "tty_poll"))
2073 ld
= tty_ldisc_ref_wait(tty
);
2075 return hung_up_tty_poll(filp
, wait
);
2077 ret
= ld
->ops
->poll(tty
, filp
, wait
);
2078 tty_ldisc_deref(ld
);
2082 static int __tty_fasync(int fd
, struct file
*filp
, int on
)
2084 struct tty_struct
*tty
= file_tty(filp
);
2085 unsigned long flags
;
2088 if (tty_paranoia_check(tty
, file_inode(filp
), "tty_fasync"))
2091 retval
= fasync_helper(fd
, filp
, on
, &tty
->fasync
);
2099 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2102 type
= PIDTYPE_PGID
;
2104 pid
= task_pid(current
);
2108 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2109 __f_setown(filp
, pid
, type
, 0);
2117 static int tty_fasync(int fd
, struct file
*filp
, int on
)
2119 struct tty_struct
*tty
= file_tty(filp
);
2120 int retval
= -ENOTTY
;
2123 if (!tty_hung_up_p(filp
))
2124 retval
= __tty_fasync(fd
, filp
, on
);
2131 * tiocsti - fake input character
2132 * @tty: tty to fake input into
2133 * @p: pointer to character
2135 * Fake input to a tty device. Does the necessary locking and
2138 * FIXME: does not honour flow control ??
2141 * Called functions take tty_ldiscs_lock
2142 * current->signal->tty check is safe without locks
2144 * FIXME: may race normal receive processing
2147 static int tiocsti(struct tty_struct
*tty
, char __user
*p
)
2150 struct tty_ldisc
*ld
;
2152 if ((current
->signal
->tty
!= tty
) && !capable(CAP_SYS_ADMIN
))
2154 if (get_user(ch
, p
))
2156 tty_audit_tiocsti(tty
, ch
);
2157 ld
= tty_ldisc_ref_wait(tty
);
2160 ld
->ops
->receive_buf(tty
, &ch
, &mbz
, 1);
2161 tty_ldisc_deref(ld
);
2166 * tiocgwinsz - implement window query ioctl
2168 * @arg: user buffer for result
2170 * Copies the kernel idea of the window size into the user buffer.
2172 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2176 static int tiocgwinsz(struct tty_struct
*tty
, struct winsize __user
*arg
)
2180 mutex_lock(&tty
->winsize_mutex
);
2181 err
= copy_to_user(arg
, &tty
->winsize
, sizeof(*arg
));
2182 mutex_unlock(&tty
->winsize_mutex
);
2184 return err
? -EFAULT
: 0;
2188 * tty_do_resize - resize event
2189 * @tty: tty being resized
2190 * @rows: rows (character)
2191 * @cols: cols (character)
2193 * Update the termios variables and send the necessary signals to
2194 * peform a terminal resize correctly
2197 int tty_do_resize(struct tty_struct
*tty
, struct winsize
*ws
)
2202 mutex_lock(&tty
->winsize_mutex
);
2203 if (!memcmp(ws
, &tty
->winsize
, sizeof(*ws
)))
2206 /* Signal the foreground process group */
2207 pgrp
= tty_get_pgrp(tty
);
2209 kill_pgrp(pgrp
, SIGWINCH
, 1);
2214 mutex_unlock(&tty
->winsize_mutex
);
2217 EXPORT_SYMBOL(tty_do_resize
);
2220 * tiocswinsz - implement window size set ioctl
2221 * @tty; tty side of tty
2222 * @arg: user buffer for result
2224 * Copies the user idea of the window size to the kernel. Traditionally
2225 * this is just advisory information but for the Linux console it
2226 * actually has driver level meaning and triggers a VC resize.
2229 * Driver dependent. The default do_resize method takes the
2230 * tty termios mutex and ctrl_lock. The console takes its own lock
2231 * then calls into the default method.
2234 static int tiocswinsz(struct tty_struct
*tty
, struct winsize __user
*arg
)
2236 struct winsize tmp_ws
;
2237 if (copy_from_user(&tmp_ws
, arg
, sizeof(*arg
)))
2240 if (tty
->ops
->resize
)
2241 return tty
->ops
->resize(tty
, &tmp_ws
);
2243 return tty_do_resize(tty
, &tmp_ws
);
2247 * tioccons - allow admin to move logical console
2248 * @file: the file to become console
2250 * Allow the administrator to move the redirected console device
2252 * Locking: uses redirect_lock to guard the redirect information
2255 static int tioccons(struct file
*file
)
2257 if (!capable(CAP_SYS_ADMIN
))
2259 if (file
->f_op
->write
== redirected_tty_write
) {
2261 spin_lock(&redirect_lock
);
2264 spin_unlock(&redirect_lock
);
2269 spin_lock(&redirect_lock
);
2271 spin_unlock(&redirect_lock
);
2274 redirect
= get_file(file
);
2275 spin_unlock(&redirect_lock
);
2280 * fionbio - non blocking ioctl
2281 * @file: file to set blocking value
2282 * @p: user parameter
2284 * Historical tty interfaces had a blocking control ioctl before
2285 * the generic functionality existed. This piece of history is preserved
2286 * in the expected tty API of posix OS's.
2288 * Locking: none, the open file handle ensures it won't go away.
2291 static int fionbio(struct file
*file
, int __user
*p
)
2295 if (get_user(nonblock
, p
))
2298 spin_lock(&file
->f_lock
);
2300 file
->f_flags
|= O_NONBLOCK
;
2302 file
->f_flags
&= ~O_NONBLOCK
;
2303 spin_unlock(&file
->f_lock
);
2308 * tiocsetd - set line discipline
2310 * @p: pointer to user data
2312 * Set the line discipline according to user request.
2314 * Locking: see tty_set_ldisc, this function is just a helper
2317 static int tiocsetd(struct tty_struct
*tty
, int __user
*p
)
2322 if (get_user(disc
, p
))
2325 ret
= tty_set_ldisc(tty
, disc
);
2331 * tiocgetd - get line discipline
2333 * @p: pointer to user data
2335 * Retrieves the line discipline id directly from the ldisc.
2337 * Locking: waits for ldisc reference (in case the line discipline
2338 * is changing or the tty is being hungup)
2341 static int tiocgetd(struct tty_struct
*tty
, int __user
*p
)
2343 struct tty_ldisc
*ld
;
2346 ld
= tty_ldisc_ref_wait(tty
);
2349 ret
= put_user(ld
->ops
->num
, p
);
2350 tty_ldisc_deref(ld
);
2355 * send_break - performed time break
2356 * @tty: device to break on
2357 * @duration: timeout in mS
2359 * Perform a timed break on hardware that lacks its own driver level
2360 * timed break functionality.
2363 * atomic_write_lock serializes
2367 static int send_break(struct tty_struct
*tty
, unsigned int duration
)
2371 if (tty
->ops
->break_ctl
== NULL
)
2374 if (tty
->driver
->flags
& TTY_DRIVER_HARDWARE_BREAK
)
2375 retval
= tty
->ops
->break_ctl(tty
, duration
);
2377 /* Do the work ourselves */
2378 if (tty_write_lock(tty
, 0) < 0)
2380 retval
= tty
->ops
->break_ctl(tty
, -1);
2383 if (!signal_pending(current
))
2384 msleep_interruptible(duration
);
2385 retval
= tty
->ops
->break_ctl(tty
, 0);
2387 tty_write_unlock(tty
);
2388 if (signal_pending(current
))
2395 * tty_tiocmget - get modem status
2397 * @file: user file pointer
2398 * @p: pointer to result
2400 * Obtain the modem status bits from the tty driver if the feature
2401 * is supported. Return -EINVAL if it is not available.
2403 * Locking: none (up to the driver)
2406 static int tty_tiocmget(struct tty_struct
*tty
, int __user
*p
)
2408 int retval
= -EINVAL
;
2410 if (tty
->ops
->tiocmget
) {
2411 retval
= tty
->ops
->tiocmget(tty
);
2414 retval
= put_user(retval
, p
);
2420 * tty_tiocmset - set modem status
2422 * @cmd: command - clear bits, set bits or set all
2423 * @p: pointer to desired bits
2425 * Set the modem status bits from the tty driver if the feature
2426 * is supported. Return -EINVAL if it is not available.
2428 * Locking: none (up to the driver)
2431 static int tty_tiocmset(struct tty_struct
*tty
, unsigned int cmd
,
2435 unsigned int set
, clear
, val
;
2437 if (tty
->ops
->tiocmset
== NULL
)
2440 retval
= get_user(val
, p
);
2456 set
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
2457 clear
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
2458 return tty
->ops
->tiocmset(tty
, set
, clear
);
2461 static int tty_tiocgicount(struct tty_struct
*tty
, void __user
*arg
)
2463 int retval
= -EINVAL
;
2464 struct serial_icounter_struct icount
;
2465 memset(&icount
, 0, sizeof(icount
));
2466 if (tty
->ops
->get_icount
)
2467 retval
= tty
->ops
->get_icount(tty
, &icount
);
2470 if (copy_to_user(arg
, &icount
, sizeof(icount
)))
2475 static void tty_warn_deprecated_flags(struct serial_struct __user
*ss
)
2477 static DEFINE_RATELIMIT_STATE(depr_flags
,
2478 DEFAULT_RATELIMIT_INTERVAL
,
2479 DEFAULT_RATELIMIT_BURST
);
2480 char comm
[TASK_COMM_LEN
];
2483 if (get_user(flags
, &ss
->flags
))
2486 flags
&= ASYNC_DEPRECATED
;
2488 if (flags
&& __ratelimit(&depr_flags
))
2489 pr_warn("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2490 __func__
, get_task_comm(comm
, current
), flags
);
2494 * if pty, return the slave side (real_tty)
2495 * otherwise, return self
2497 static struct tty_struct
*tty_pair_get_tty(struct tty_struct
*tty
)
2499 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2500 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
2506 * Split this up, as gcc can choke on it otherwise..
2508 long tty_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
2510 struct tty_struct
*tty
= file_tty(file
);
2511 struct tty_struct
*real_tty
;
2512 void __user
*p
= (void __user
*)arg
;
2514 struct tty_ldisc
*ld
;
2516 if (tty_paranoia_check(tty
, file_inode(file
), "tty_ioctl"))
2519 real_tty
= tty_pair_get_tty(tty
);
2522 * Factor out some common prep work
2530 retval
= tty_check_change(tty
);
2533 if (cmd
!= TIOCCBRK
) {
2534 tty_wait_until_sent(tty
, 0);
2535 if (signal_pending(current
))
2546 return tiocsti(tty
, p
);
2548 return tiocgwinsz(real_tty
, p
);
2550 return tiocswinsz(real_tty
, p
);
2552 return real_tty
!= tty
? -EINVAL
: tioccons(file
);
2554 return fionbio(file
, p
);
2556 set_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2559 clear_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2563 int excl
= test_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2564 return put_user(excl
, (int __user
*)p
);
2567 return tiocgetd(tty
, p
);
2569 return tiocsetd(tty
, p
);
2571 if (!capable(CAP_SYS_ADMIN
))
2577 unsigned int ret
= new_encode_dev(tty_devnum(real_tty
));
2578 return put_user(ret
, (unsigned int __user
*)p
);
2583 case TIOCSBRK
: /* Turn break on, unconditionally */
2584 if (tty
->ops
->break_ctl
)
2585 return tty
->ops
->break_ctl(tty
, -1);
2587 case TIOCCBRK
: /* Turn break off, unconditionally */
2588 if (tty
->ops
->break_ctl
)
2589 return tty
->ops
->break_ctl(tty
, 0);
2591 case TCSBRK
: /* SVID version: non-zero arg --> no break */
2592 /* non-zero arg means wait for all output data
2593 * to be sent (performed above) but don't send break.
2594 * This is used by the tcdrain() termios function.
2597 return send_break(tty
, 250);
2599 case TCSBRKP
: /* support for POSIX tcsendbreak() */
2600 return send_break(tty
, arg
? arg
*100 : 250);
2603 return tty_tiocmget(tty
, p
);
2607 return tty_tiocmset(tty
, cmd
, p
);
2609 retval
= tty_tiocgicount(tty
, p
);
2610 /* For the moment allow fall through to the old method */
2611 if (retval
!= -EINVAL
)
2618 /* flush tty buffer and allow ldisc to process ioctl */
2619 tty_buffer_flush(tty
, NULL
);
2624 tty_warn_deprecated_flags(p
);
2627 /* Special because the struct file is needed */
2628 return ptm_open_peer(file
, tty
, (int)arg
);
2630 retval
= tty_jobctrl_ioctl(tty
, real_tty
, file
, cmd
, arg
);
2631 if (retval
!= -ENOIOCTLCMD
)
2634 if (tty
->ops
->ioctl
) {
2635 retval
= tty
->ops
->ioctl(tty
, cmd
, arg
);
2636 if (retval
!= -ENOIOCTLCMD
)
2639 ld
= tty_ldisc_ref_wait(tty
);
2641 return hung_up_tty_ioctl(file
, cmd
, arg
);
2643 if (ld
->ops
->ioctl
) {
2644 retval
= ld
->ops
->ioctl(tty
, file
, cmd
, arg
);
2645 if (retval
== -ENOIOCTLCMD
)
2648 tty_ldisc_deref(ld
);
2652 #ifdef CONFIG_COMPAT
2653 static long tty_compat_ioctl(struct file
*file
, unsigned int cmd
,
2656 struct tty_struct
*tty
= file_tty(file
);
2657 struct tty_ldisc
*ld
;
2658 int retval
= -ENOIOCTLCMD
;
2660 if (tty_paranoia_check(tty
, file_inode(file
), "tty_ioctl"))
2663 if (tty
->ops
->compat_ioctl
) {
2664 retval
= tty
->ops
->compat_ioctl(tty
, cmd
, arg
);
2665 if (retval
!= -ENOIOCTLCMD
)
2669 ld
= tty_ldisc_ref_wait(tty
);
2671 return hung_up_tty_compat_ioctl(file
, cmd
, arg
);
2672 if (ld
->ops
->compat_ioctl
)
2673 retval
= ld
->ops
->compat_ioctl(tty
, file
, cmd
, arg
);
2675 retval
= n_tty_compat_ioctl_helper(tty
, file
, cmd
, arg
);
2676 tty_ldisc_deref(ld
);
2682 static int this_tty(const void *t
, struct file
*file
, unsigned fd
)
2684 if (likely(file
->f_op
->read
!= tty_read
))
2686 return file_tty(file
) != t
? 0 : fd
+ 1;
2690 * This implements the "Secure Attention Key" --- the idea is to
2691 * prevent trojan horses by killing all processes associated with this
2692 * tty when the user hits the "Secure Attention Key". Required for
2693 * super-paranoid applications --- see the Orange Book for more details.
2695 * This code could be nicer; ideally it should send a HUP, wait a few
2696 * seconds, then send a INT, and then a KILL signal. But you then
2697 * have to coordinate with the init process, since all processes associated
2698 * with the current tty must be dead before the new getty is allowed
2701 * Now, if it would be correct ;-/ The current code has a nasty hole -
2702 * it doesn't catch files in flight. We may send the descriptor to ourselves
2703 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2705 * Nasty bug: do_SAK is being called in interrupt context. This can
2706 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2708 void __do_SAK(struct tty_struct
*tty
)
2713 struct task_struct
*g
, *p
;
2714 struct pid
*session
;
2719 session
= tty
->session
;
2721 tty_ldisc_flush(tty
);
2723 tty_driver_flush_buffer(tty
);
2725 read_lock(&tasklist_lock
);
2726 /* Kill the entire session */
2727 do_each_pid_task(session
, PIDTYPE_SID
, p
) {
2728 tty_notice(tty
, "SAK: killed process %d (%s): by session\n",
2729 task_pid_nr(p
), p
->comm
);
2730 send_sig(SIGKILL
, p
, 1);
2731 } while_each_pid_task(session
, PIDTYPE_SID
, p
);
2733 /* Now kill any processes that happen to have the tty open */
2734 do_each_thread(g
, p
) {
2735 if (p
->signal
->tty
== tty
) {
2736 tty_notice(tty
, "SAK: killed process %d (%s): by controlling tty\n",
2737 task_pid_nr(p
), p
->comm
);
2738 send_sig(SIGKILL
, p
, 1);
2742 i
= iterate_fd(p
->files
, 0, this_tty
, tty
);
2744 tty_notice(tty
, "SAK: killed process %d (%s): by fd#%d\n",
2745 task_pid_nr(p
), p
->comm
, i
- 1);
2746 force_sig(SIGKILL
, p
);
2749 } while_each_thread(g
, p
);
2750 read_unlock(&tasklist_lock
);
2754 static void do_SAK_work(struct work_struct
*work
)
2756 struct tty_struct
*tty
=
2757 container_of(work
, struct tty_struct
, SAK_work
);
2762 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2763 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2764 * the values which we write to it will be identical to the values which it
2765 * already has. --akpm
2767 void do_SAK(struct tty_struct
*tty
)
2771 schedule_work(&tty
->SAK_work
);
2774 EXPORT_SYMBOL(do_SAK
);
2776 static int dev_match_devt(struct device
*dev
, const void *data
)
2778 const dev_t
*devt
= data
;
2779 return dev
->devt
== *devt
;
2782 /* Must put_device() after it's unused! */
2783 static struct device
*tty_get_device(struct tty_struct
*tty
)
2785 dev_t devt
= tty_devnum(tty
);
2786 return class_find_device(tty_class
, NULL
, &devt
, dev_match_devt
);
2793 * This subroutine allocates and initializes a tty structure.
2795 * Locking: none - tty in question is not exposed at this point
2798 struct tty_struct
*alloc_tty_struct(struct tty_driver
*driver
, int idx
)
2800 struct tty_struct
*tty
;
2802 tty
= kzalloc(sizeof(*tty
), GFP_KERNEL
);
2806 kref_init(&tty
->kref
);
2807 tty
->magic
= TTY_MAGIC
;
2808 tty_ldisc_init(tty
);
2809 tty
->session
= NULL
;
2811 mutex_init(&tty
->legacy_mutex
);
2812 mutex_init(&tty
->throttle_mutex
);
2813 init_rwsem(&tty
->termios_rwsem
);
2814 mutex_init(&tty
->winsize_mutex
);
2815 init_ldsem(&tty
->ldisc_sem
);
2816 init_waitqueue_head(&tty
->write_wait
);
2817 init_waitqueue_head(&tty
->read_wait
);
2818 INIT_WORK(&tty
->hangup_work
, do_tty_hangup
);
2819 mutex_init(&tty
->atomic_write_lock
);
2820 spin_lock_init(&tty
->ctrl_lock
);
2821 spin_lock_init(&tty
->flow_lock
);
2822 spin_lock_init(&tty
->files_lock
);
2823 INIT_LIST_HEAD(&tty
->tty_files
);
2824 INIT_WORK(&tty
->SAK_work
, do_SAK_work
);
2826 tty
->driver
= driver
;
2827 tty
->ops
= driver
->ops
;
2829 tty_line_name(driver
, idx
, tty
->name
);
2830 tty
->dev
= tty_get_device(tty
);
2836 * tty_put_char - write one character to a tty
2840 * Write one byte to the tty using the provided put_char method
2841 * if present. Returns the number of characters successfully output.
2843 * Note: the specific put_char operation in the driver layer may go
2844 * away soon. Don't call it directly, use this method
2847 int tty_put_char(struct tty_struct
*tty
, unsigned char ch
)
2849 if (tty
->ops
->put_char
)
2850 return tty
->ops
->put_char(tty
, ch
);
2851 return tty
->ops
->write(tty
, &ch
, 1);
2853 EXPORT_SYMBOL_GPL(tty_put_char
);
2855 struct class *tty_class
;
2857 static int tty_cdev_add(struct tty_driver
*driver
, dev_t dev
,
2858 unsigned int index
, unsigned int count
)
2862 /* init here, since reused cdevs cause crashes */
2863 driver
->cdevs
[index
] = cdev_alloc();
2864 if (!driver
->cdevs
[index
])
2866 driver
->cdevs
[index
]->ops
= &tty_fops
;
2867 driver
->cdevs
[index
]->owner
= driver
->owner
;
2868 err
= cdev_add(driver
->cdevs
[index
], dev
, count
);
2870 kobject_put(&driver
->cdevs
[index
]->kobj
);
2875 * tty_register_device - register a tty device
2876 * @driver: the tty driver that describes the tty device
2877 * @index: the index in the tty driver for this tty device
2878 * @device: a struct device that is associated with this tty device.
2879 * This field is optional, if there is no known struct device
2880 * for this tty device it can be set to NULL safely.
2882 * Returns a pointer to the struct device for this tty device
2883 * (or ERR_PTR(-EFOO) on error).
2885 * This call is required to be made to register an individual tty device
2886 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2887 * that bit is not set, this function should not be called by a tty
2893 struct device
*tty_register_device(struct tty_driver
*driver
, unsigned index
,
2894 struct device
*device
)
2896 return tty_register_device_attr(driver
, index
, device
, NULL
, NULL
);
2898 EXPORT_SYMBOL(tty_register_device
);
2900 static void tty_device_create_release(struct device
*dev
)
2902 dev_dbg(dev
, "releasing...\n");
2907 * tty_register_device_attr - register a tty device
2908 * @driver: the tty driver that describes the tty device
2909 * @index: the index in the tty driver for this tty device
2910 * @device: a struct device that is associated with this tty device.
2911 * This field is optional, if there is no known struct device
2912 * for this tty device it can be set to NULL safely.
2913 * @drvdata: Driver data to be set to device.
2914 * @attr_grp: Attribute group to be set on device.
2916 * Returns a pointer to the struct device for this tty device
2917 * (or ERR_PTR(-EFOO) on error).
2919 * This call is required to be made to register an individual tty device
2920 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2921 * that bit is not set, this function should not be called by a tty
2926 struct device
*tty_register_device_attr(struct tty_driver
*driver
,
2927 unsigned index
, struct device
*device
,
2929 const struct attribute_group
**attr_grp
)
2932 dev_t devt
= MKDEV(driver
->major
, driver
->minor_start
) + index
;
2933 struct ktermios
*tp
;
2937 if (index
>= driver
->num
) {
2938 pr_err("%s: Attempt to register invalid tty line number (%d)\n",
2939 driver
->name
, index
);
2940 return ERR_PTR(-EINVAL
);
2943 if (driver
->type
== TTY_DRIVER_TYPE_PTY
)
2944 pty_line_name(driver
, index
, name
);
2946 tty_line_name(driver
, index
, name
);
2948 dev
= kzalloc(sizeof(*dev
), GFP_KERNEL
);
2950 return ERR_PTR(-ENOMEM
);
2953 dev
->class = tty_class
;
2954 dev
->parent
= device
;
2955 dev
->release
= tty_device_create_release
;
2956 dev_set_name(dev
, "%s", name
);
2957 dev
->groups
= attr_grp
;
2958 dev_set_drvdata(dev
, drvdata
);
2960 dev_set_uevent_suppress(dev
, 1);
2962 retval
= device_register(dev
);
2966 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
)) {
2968 * Free any saved termios data so that the termios state is
2969 * reset when reusing a minor number.
2971 tp
= driver
->termios
[index
];
2973 driver
->termios
[index
] = NULL
;
2977 retval
= tty_cdev_add(driver
, devt
, index
, 1);
2982 dev_set_uevent_suppress(dev
, 0);
2983 kobject_uevent(&dev
->kobj
, KOBJ_ADD
);
2992 return ERR_PTR(retval
);
2994 EXPORT_SYMBOL_GPL(tty_register_device_attr
);
2997 * tty_unregister_device - unregister a tty device
2998 * @driver: the tty driver that describes the tty device
2999 * @index: the index in the tty driver for this tty device
3001 * If a tty device is registered with a call to tty_register_device() then
3002 * this function must be called when the tty device is gone.
3007 void tty_unregister_device(struct tty_driver
*driver
, unsigned index
)
3009 device_destroy(tty_class
,
3010 MKDEV(driver
->major
, driver
->minor_start
) + index
);
3011 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
)) {
3012 cdev_del(driver
->cdevs
[index
]);
3013 driver
->cdevs
[index
] = NULL
;
3016 EXPORT_SYMBOL(tty_unregister_device
);
3019 * __tty_alloc_driver -- allocate tty driver
3020 * @lines: count of lines this driver can handle at most
3021 * @owner: module which is responsible for this driver
3022 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3024 * This should not be called directly, some of the provided macros should be
3025 * used instead. Use IS_ERR and friends on @retval.
3027 struct tty_driver
*__tty_alloc_driver(unsigned int lines
, struct module
*owner
,
3028 unsigned long flags
)
3030 struct tty_driver
*driver
;
3031 unsigned int cdevs
= 1;
3034 if (!lines
|| (flags
& TTY_DRIVER_UNNUMBERED_NODE
&& lines
> 1))
3035 return ERR_PTR(-EINVAL
);
3037 driver
= kzalloc(sizeof(struct tty_driver
), GFP_KERNEL
);
3039 return ERR_PTR(-ENOMEM
);
3041 kref_init(&driver
->kref
);
3042 driver
->magic
= TTY_DRIVER_MAGIC
;
3043 driver
->num
= lines
;
3044 driver
->owner
= owner
;
3045 driver
->flags
= flags
;
3047 if (!(flags
& TTY_DRIVER_DEVPTS_MEM
)) {
3048 driver
->ttys
= kcalloc(lines
, sizeof(*driver
->ttys
),
3050 driver
->termios
= kcalloc(lines
, sizeof(*driver
->termios
),
3052 if (!driver
->ttys
|| !driver
->termios
) {
3058 if (!(flags
& TTY_DRIVER_DYNAMIC_ALLOC
)) {
3059 driver
->ports
= kcalloc(lines
, sizeof(*driver
->ports
),
3061 if (!driver
->ports
) {
3068 driver
->cdevs
= kcalloc(cdevs
, sizeof(*driver
->cdevs
), GFP_KERNEL
);
3069 if (!driver
->cdevs
) {
3076 kfree(driver
->ports
);
3077 kfree(driver
->ttys
);
3078 kfree(driver
->termios
);
3079 kfree(driver
->cdevs
);
3081 return ERR_PTR(err
);
3083 EXPORT_SYMBOL(__tty_alloc_driver
);
3085 static void destruct_tty_driver(struct kref
*kref
)
3087 struct tty_driver
*driver
= container_of(kref
, struct tty_driver
, kref
);
3089 struct ktermios
*tp
;
3091 if (driver
->flags
& TTY_DRIVER_INSTALLED
) {
3092 for (i
= 0; i
< driver
->num
; i
++) {
3093 tp
= driver
->termios
[i
];
3095 driver
->termios
[i
] = NULL
;
3098 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
))
3099 tty_unregister_device(driver
, i
);
3101 proc_tty_unregister_driver(driver
);
3102 if (driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
)
3103 cdev_del(driver
->cdevs
[0]);
3105 kfree(driver
->cdevs
);
3106 kfree(driver
->ports
);
3107 kfree(driver
->termios
);
3108 kfree(driver
->ttys
);
3112 void tty_driver_kref_put(struct tty_driver
*driver
)
3114 kref_put(&driver
->kref
, destruct_tty_driver
);
3116 EXPORT_SYMBOL(tty_driver_kref_put
);
3118 void tty_set_operations(struct tty_driver
*driver
,
3119 const struct tty_operations
*op
)
3123 EXPORT_SYMBOL(tty_set_operations
);
3125 void put_tty_driver(struct tty_driver
*d
)
3127 tty_driver_kref_put(d
);
3129 EXPORT_SYMBOL(put_tty_driver
);
3132 * Called by a tty driver to register itself.
3134 int tty_register_driver(struct tty_driver
*driver
)
3141 if (!driver
->major
) {
3142 error
= alloc_chrdev_region(&dev
, driver
->minor_start
,
3143 driver
->num
, driver
->name
);
3145 driver
->major
= MAJOR(dev
);
3146 driver
->minor_start
= MINOR(dev
);
3149 dev
= MKDEV(driver
->major
, driver
->minor_start
);
3150 error
= register_chrdev_region(dev
, driver
->num
, driver
->name
);
3155 if (driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
) {
3156 error
= tty_cdev_add(driver
, dev
, 0, driver
->num
);
3158 goto err_unreg_char
;
3161 mutex_lock(&tty_mutex
);
3162 list_add(&driver
->tty_drivers
, &tty_drivers
);
3163 mutex_unlock(&tty_mutex
);
3165 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
)) {
3166 for (i
= 0; i
< driver
->num
; i
++) {
3167 d
= tty_register_device(driver
, i
, NULL
);
3170 goto err_unreg_devs
;
3174 proc_tty_register_driver(driver
);
3175 driver
->flags
|= TTY_DRIVER_INSTALLED
;
3179 for (i
--; i
>= 0; i
--)
3180 tty_unregister_device(driver
, i
);
3182 mutex_lock(&tty_mutex
);
3183 list_del(&driver
->tty_drivers
);
3184 mutex_unlock(&tty_mutex
);
3187 unregister_chrdev_region(dev
, driver
->num
);
3191 EXPORT_SYMBOL(tty_register_driver
);
3194 * Called by a tty driver to unregister itself.
3196 int tty_unregister_driver(struct tty_driver
*driver
)
3200 if (driver
->refcount
)
3203 unregister_chrdev_region(MKDEV(driver
->major
, driver
->minor_start
),
3205 mutex_lock(&tty_mutex
);
3206 list_del(&driver
->tty_drivers
);
3207 mutex_unlock(&tty_mutex
);
3211 EXPORT_SYMBOL(tty_unregister_driver
);
3213 dev_t
tty_devnum(struct tty_struct
*tty
)
3215 return MKDEV(tty
->driver
->major
, tty
->driver
->minor_start
) + tty
->index
;
3217 EXPORT_SYMBOL(tty_devnum
);
3219 void tty_default_fops(struct file_operations
*fops
)
3224 static char *tty_devnode(struct device
*dev
, umode_t
*mode
)
3228 if (dev
->devt
== MKDEV(TTYAUX_MAJOR
, 0) ||
3229 dev
->devt
== MKDEV(TTYAUX_MAJOR
, 2))
3234 static int __init
tty_class_init(void)
3236 tty_class
= class_create(THIS_MODULE
, "tty");
3237 if (IS_ERR(tty_class
))
3238 return PTR_ERR(tty_class
);
3239 tty_class
->devnode
= tty_devnode
;
3243 postcore_initcall(tty_class_init
);
3245 /* 3/2004 jmc: why do these devices exist? */
3246 static struct cdev tty_cdev
, console_cdev
;
3248 static ssize_t
show_cons_active(struct device
*dev
,
3249 struct device_attribute
*attr
, char *buf
)
3251 struct console
*cs
[16];
3257 for_each_console(c
) {
3262 if ((c
->flags
& CON_ENABLED
) == 0)
3265 if (i
>= ARRAY_SIZE(cs
))
3269 int index
= cs
[i
]->index
;
3270 struct tty_driver
*drv
= cs
[i
]->device(cs
[i
], &index
);
3272 /* don't resolve tty0 as some programs depend on it */
3273 if (drv
&& (cs
[i
]->index
> 0 || drv
->major
!= TTY_MAJOR
))
3274 count
+= tty_line_name(drv
, index
, buf
+ count
);
3276 count
+= sprintf(buf
+ count
, "%s%d",
3277 cs
[i
]->name
, cs
[i
]->index
);
3279 count
+= sprintf(buf
+ count
, "%c", i
? ' ':'\n');
3285 static DEVICE_ATTR(active
, S_IRUGO
, show_cons_active
, NULL
);
3287 static struct attribute
*cons_dev_attrs
[] = {
3288 &dev_attr_active
.attr
,
3292 ATTRIBUTE_GROUPS(cons_dev
);
3294 static struct device
*consdev
;
3296 void console_sysfs_notify(void)
3299 sysfs_notify(&consdev
->kobj
, NULL
, "active");
3303 * Ok, now we can initialize the rest of the tty devices and can count
3304 * on memory allocations, interrupts etc..
3306 int __init
tty_init(void)
3308 cdev_init(&tty_cdev
, &tty_fops
);
3309 if (cdev_add(&tty_cdev
, MKDEV(TTYAUX_MAJOR
, 0), 1) ||
3310 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 0), 1, "/dev/tty") < 0)
3311 panic("Couldn't register /dev/tty driver\n");
3312 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 0), NULL
, "tty");
3314 cdev_init(&console_cdev
, &console_fops
);
3315 if (cdev_add(&console_cdev
, MKDEV(TTYAUX_MAJOR
, 1), 1) ||
3316 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 1), 1, "/dev/console") < 0)
3317 panic("Couldn't register /dev/console driver\n");
3318 consdev
= device_create_with_groups(tty_class
, NULL
,
3319 MKDEV(TTYAUX_MAJOR
, 1), NULL
,
3320 cons_dev_groups
, "console");
3321 if (IS_ERR(consdev
))
3325 vty_init(&console_fops
);