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 tty
->port
->itty
= tty
;
1329 * Structures all installed ... call the ldisc open routines.
1330 * If we fail here just call release_tty to clean up. No need
1331 * to decrement the use counts, as release_tty doesn't care.
1333 retval
= tty_ldisc_setup(tty
, tty
->link
);
1335 goto err_release_tty
;
1336 /* Return the tty locked so that it cannot vanish under the caller */
1341 free_tty_struct(tty
);
1343 module_put(driver
->owner
);
1344 return ERR_PTR(retval
);
1346 /* call the tty release_tty routine to clean out this slot */
1349 tty_info_ratelimited(tty
, "ldisc open failed (%d), clearing slot %d\n",
1351 release_tty(tty
, idx
);
1352 return ERR_PTR(retval
);
1355 static void tty_free_termios(struct tty_struct
*tty
)
1357 struct ktermios
*tp
;
1358 int idx
= tty
->index
;
1360 /* If the port is going to reset then it has no termios to save */
1361 if (tty
->driver
->flags
& TTY_DRIVER_RESET_TERMIOS
)
1364 /* Stash the termios data */
1365 tp
= tty
->driver
->termios
[idx
];
1367 tp
= kmalloc(sizeof(struct ktermios
), GFP_KERNEL
);
1370 tty
->driver
->termios
[idx
] = tp
;
1376 * tty_flush_works - flush all works of a tty/pty pair
1377 * @tty: tty device to flush works for (or either end of a pty pair)
1379 * Sync flush all works belonging to @tty (and the 'other' tty).
1381 static void tty_flush_works(struct tty_struct
*tty
)
1383 flush_work(&tty
->SAK_work
);
1384 flush_work(&tty
->hangup_work
);
1386 flush_work(&tty
->link
->SAK_work
);
1387 flush_work(&tty
->link
->hangup_work
);
1392 * release_one_tty - release tty structure memory
1393 * @kref: kref of tty we are obliterating
1395 * Releases memory associated with a tty structure, and clears out the
1396 * driver table slots. This function is called when a device is no longer
1397 * in use. It also gets called when setup of a device fails.
1400 * takes the file list lock internally when working on the list
1401 * of ttys that the driver keeps.
1403 * This method gets called from a work queue so that the driver private
1404 * cleanup ops can sleep (needed for USB at least)
1406 static void release_one_tty(struct work_struct
*work
)
1408 struct tty_struct
*tty
=
1409 container_of(work
, struct tty_struct
, hangup_work
);
1410 struct tty_driver
*driver
= tty
->driver
;
1411 struct module
*owner
= driver
->owner
;
1413 if (tty
->ops
->cleanup
)
1414 tty
->ops
->cleanup(tty
);
1417 tty_driver_kref_put(driver
);
1420 spin_lock(&tty
->files_lock
);
1421 list_del_init(&tty
->tty_files
);
1422 spin_unlock(&tty
->files_lock
);
1425 put_pid(tty
->session
);
1426 free_tty_struct(tty
);
1429 static void queue_release_one_tty(struct kref
*kref
)
1431 struct tty_struct
*tty
= container_of(kref
, struct tty_struct
, kref
);
1433 /* The hangup queue is now free so we can reuse it rather than
1434 waste a chunk of memory for each port */
1435 INIT_WORK(&tty
->hangup_work
, release_one_tty
);
1436 schedule_work(&tty
->hangup_work
);
1440 * tty_kref_put - release a tty kref
1443 * Release a reference to a tty device and if need be let the kref
1444 * layer destruct the object for us
1447 void tty_kref_put(struct tty_struct
*tty
)
1450 kref_put(&tty
->kref
, queue_release_one_tty
);
1452 EXPORT_SYMBOL(tty_kref_put
);
1455 * release_tty - release tty structure memory
1457 * Release both @tty and a possible linked partner (think pty pair),
1458 * and decrement the refcount of the backing module.
1462 * takes the file list lock internally when working on the list
1463 * of ttys that the driver keeps.
1466 static void release_tty(struct tty_struct
*tty
, int idx
)
1468 /* This should always be true but check for the moment */
1469 WARN_ON(tty
->index
!= idx
);
1470 WARN_ON(!mutex_is_locked(&tty_mutex
));
1471 if (tty
->ops
->shutdown
)
1472 tty
->ops
->shutdown(tty
);
1473 tty_free_termios(tty
);
1474 tty_driver_remove_tty(tty
->driver
, tty
);
1475 tty
->port
->itty
= NULL
;
1477 tty
->link
->port
->itty
= NULL
;
1478 tty_buffer_cancel_work(tty
->port
);
1480 tty_kref_put(tty
->link
);
1485 * tty_release_checks - check a tty before real release
1486 * @tty: tty to check
1487 * @o_tty: link of @tty (if any)
1488 * @idx: index of the tty
1490 * Performs some paranoid checking before true release of the @tty.
1491 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1493 static int tty_release_checks(struct tty_struct
*tty
, int idx
)
1495 #ifdef TTY_PARANOIA_CHECK
1496 if (idx
< 0 || idx
>= tty
->driver
->num
) {
1497 tty_debug(tty
, "bad idx %d\n", idx
);
1501 /* not much to check for devpts */
1502 if (tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
)
1505 if (tty
!= tty
->driver
->ttys
[idx
]) {
1506 tty_debug(tty
, "bad driver table[%d] = %p\n",
1507 idx
, tty
->driver
->ttys
[idx
]);
1510 if (tty
->driver
->other
) {
1511 struct tty_struct
*o_tty
= tty
->link
;
1513 if (o_tty
!= tty
->driver
->other
->ttys
[idx
]) {
1514 tty_debug(tty
, "bad other table[%d] = %p\n",
1515 idx
, tty
->driver
->other
->ttys
[idx
]);
1518 if (o_tty
->link
!= tty
) {
1519 tty_debug(tty
, "bad link = %p\n", o_tty
->link
);
1528 * tty_kclose - closes tty opened by tty_kopen
1531 * Performs the final steps to release and free a tty device. It is the
1532 * same as tty_release_struct except that it also resets TTY_PORT_KOPENED
1533 * flag on tty->port.
1535 void tty_kclose(struct tty_struct
*tty
)
1538 * Ask the line discipline code to release its structures
1540 tty_ldisc_release(tty
);
1542 /* Wait for pending work before tty destruction commmences */
1543 tty_flush_works(tty
);
1545 tty_debug_hangup(tty
, "freeing structure\n");
1547 * The release_tty function takes care of the details of clearing
1548 * the slots and preserving the termios structure. The tty_unlock_pair
1549 * should be safe as we keep a kref while the tty is locked (so the
1550 * unlock never unlocks a freed tty).
1552 mutex_lock(&tty_mutex
);
1553 tty_port_set_kopened(tty
->port
, 0);
1554 release_tty(tty
, tty
->index
);
1555 mutex_unlock(&tty_mutex
);
1557 EXPORT_SYMBOL_GPL(tty_kclose
);
1560 * tty_release_struct - release a tty struct
1562 * @idx: index of the tty
1564 * Performs the final steps to release and free a tty device. It is
1565 * roughly the reverse of tty_init_dev.
1567 void tty_release_struct(struct tty_struct
*tty
, int idx
)
1570 * Ask the line discipline code to release its structures
1572 tty_ldisc_release(tty
);
1574 /* Wait for pending work before tty destruction commmences */
1575 tty_flush_works(tty
);
1577 tty_debug_hangup(tty
, "freeing structure\n");
1579 * The release_tty function takes care of the details of clearing
1580 * the slots and preserving the termios structure. The tty_unlock_pair
1581 * should be safe as we keep a kref while the tty is locked (so the
1582 * unlock never unlocks a freed tty).
1584 mutex_lock(&tty_mutex
);
1585 release_tty(tty
, idx
);
1586 mutex_unlock(&tty_mutex
);
1588 EXPORT_SYMBOL_GPL(tty_release_struct
);
1591 * tty_release - vfs callback for close
1592 * @inode: inode of tty
1593 * @filp: file pointer for handle to tty
1595 * Called the last time each file handle is closed that references
1596 * this tty. There may however be several such references.
1599 * Takes bkl. See tty_release_dev
1601 * Even releasing the tty structures is a tricky business.. We have
1602 * to be very careful that the structures are all released at the
1603 * same time, as interrupts might otherwise get the wrong pointers.
1605 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1606 * lead to double frees or releasing memory still in use.
1609 int tty_release(struct inode
*inode
, struct file
*filp
)
1611 struct tty_struct
*tty
= file_tty(filp
);
1612 struct tty_struct
*o_tty
= NULL
;
1613 int do_sleep
, final
;
1618 if (tty_paranoia_check(tty
, inode
, __func__
))
1622 check_tty_count(tty
, __func__
);
1624 __tty_fasync(-1, filp
, 0);
1627 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1628 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
1631 if (tty_release_checks(tty
, idx
)) {
1636 tty_debug_hangup(tty
, "releasing (count=%d)\n", tty
->count
);
1638 if (tty
->ops
->close
)
1639 tty
->ops
->close(tty
, filp
);
1641 /* If tty is pty master, lock the slave pty (stable lock order) */
1642 tty_lock_slave(o_tty
);
1645 * Sanity check: if tty->count is going to zero, there shouldn't be
1646 * any waiters on tty->read_wait or tty->write_wait. We test the
1647 * wait queues and kick everyone out _before_ actually starting to
1648 * close. This ensures that we won't block while releasing the tty
1651 * The test for the o_tty closing is necessary, since the master and
1652 * slave sides may close in any order. If the slave side closes out
1653 * first, its count will be one, since the master side holds an open.
1654 * Thus this test wouldn't be triggered at the time the slave closed,
1660 if (tty
->count
<= 1) {
1661 if (waitqueue_active(&tty
->read_wait
)) {
1662 wake_up_poll(&tty
->read_wait
, POLLIN
);
1665 if (waitqueue_active(&tty
->write_wait
)) {
1666 wake_up_poll(&tty
->write_wait
, POLLOUT
);
1670 if (o_tty
&& o_tty
->count
<= 1) {
1671 if (waitqueue_active(&o_tty
->read_wait
)) {
1672 wake_up_poll(&o_tty
->read_wait
, POLLIN
);
1675 if (waitqueue_active(&o_tty
->write_wait
)) {
1676 wake_up_poll(&o_tty
->write_wait
, POLLOUT
);
1685 tty_warn(tty
, "read/write wait queue active!\n");
1687 schedule_timeout_killable(timeout
);
1688 if (timeout
< 120 * HZ
)
1689 timeout
= 2 * timeout
+ 1;
1691 timeout
= MAX_SCHEDULE_TIMEOUT
;
1695 if (--o_tty
->count
< 0) {
1696 tty_warn(tty
, "bad slave count (%d)\n", o_tty
->count
);
1700 if (--tty
->count
< 0) {
1701 tty_warn(tty
, "bad tty->count (%d)\n", tty
->count
);
1706 * We've decremented tty->count, so we need to remove this file
1707 * descriptor off the tty->tty_files list; this serves two
1709 * - check_tty_count sees the correct number of file descriptors
1710 * associated with this tty.
1711 * - do_tty_hangup no longer sees this file descriptor as
1712 * something that needs to be handled for hangups.
1717 * Perform some housekeeping before deciding whether to return.
1719 * If _either_ side is closing, make sure there aren't any
1720 * processes that still think tty or o_tty is their controlling
1724 read_lock(&tasklist_lock
);
1725 session_clear_tty(tty
->session
);
1727 session_clear_tty(o_tty
->session
);
1728 read_unlock(&tasklist_lock
);
1731 /* check whether both sides are closing ... */
1732 final
= !tty
->count
&& !(o_tty
&& o_tty
->count
);
1734 tty_unlock_slave(o_tty
);
1737 /* At this point, the tty->count == 0 should ensure a dead tty
1738 cannot be re-opened by a racing opener */
1743 tty_debug_hangup(tty
, "final close\n");
1745 tty_release_struct(tty
, idx
);
1750 * tty_open_current_tty - get locked tty of current task
1751 * @device: device number
1752 * @filp: file pointer to tty
1753 * @return: locked tty of the current task iff @device is /dev/tty
1755 * Performs a re-open of the current task's controlling tty.
1757 * We cannot return driver and index like for the other nodes because
1758 * devpts will not work then. It expects inodes to be from devpts FS.
1760 static struct tty_struct
*tty_open_current_tty(dev_t device
, struct file
*filp
)
1762 struct tty_struct
*tty
;
1765 if (device
!= MKDEV(TTYAUX_MAJOR
, 0))
1768 tty
= get_current_tty();
1770 return ERR_PTR(-ENXIO
);
1772 filp
->f_flags
|= O_NONBLOCK
; /* Don't let /dev/tty block */
1775 tty_kref_put(tty
); /* safe to drop the kref now */
1777 retval
= tty_reopen(tty
);
1780 tty
= ERR_PTR(retval
);
1786 * tty_lookup_driver - lookup a tty driver for a given device file
1787 * @device: device number
1788 * @filp: file pointer to tty
1789 * @index: index for the device in the @return driver
1790 * @return: driver for this inode (with increased refcount)
1792 * If @return is not erroneous, the caller is responsible to decrement the
1793 * refcount by tty_driver_kref_put.
1795 * Locking: tty_mutex protects get_tty_driver
1797 static struct tty_driver
*tty_lookup_driver(dev_t device
, struct file
*filp
,
1800 struct tty_driver
*driver
;
1804 case MKDEV(TTY_MAJOR
, 0): {
1805 extern struct tty_driver
*console_driver
;
1806 driver
= tty_driver_kref_get(console_driver
);
1807 *index
= fg_console
;
1811 case MKDEV(TTYAUX_MAJOR
, 1): {
1812 struct tty_driver
*console_driver
= console_device(index
);
1813 if (console_driver
) {
1814 driver
= tty_driver_kref_get(console_driver
);
1815 if (driver
&& filp
) {
1816 /* Don't let /dev/console block */
1817 filp
->f_flags
|= O_NONBLOCK
;
1821 return ERR_PTR(-ENODEV
);
1824 driver
= get_tty_driver(device
, index
);
1826 return ERR_PTR(-ENODEV
);
1833 * tty_kopen - open a tty device for kernel
1834 * @device: dev_t of device to open
1836 * Opens tty exclusively for kernel. Performs the driver lookup,
1837 * makes sure it's not already opened and performs the first-time
1838 * tty initialization.
1840 * Returns the locked initialized &tty_struct
1842 * Claims the global tty_mutex to serialize:
1843 * - concurrent first-time tty initialization
1844 * - concurrent tty driver removal w/ lookup
1845 * - concurrent tty removal from driver table
1847 struct tty_struct
*tty_kopen(dev_t device
)
1849 struct tty_struct
*tty
;
1850 struct tty_driver
*driver
= NULL
;
1853 mutex_lock(&tty_mutex
);
1854 driver
= tty_lookup_driver(device
, NULL
, &index
);
1855 if (IS_ERR(driver
)) {
1856 mutex_unlock(&tty_mutex
);
1857 return ERR_CAST(driver
);
1860 /* check whether we're reopening an existing tty */
1861 tty
= tty_driver_lookup_tty(driver
, NULL
, index
);
1866 /* drop kref from tty_driver_lookup_tty() */
1868 tty
= ERR_PTR(-EBUSY
);
1869 } else { /* tty_init_dev returns tty with the tty_lock held */
1870 tty
= tty_init_dev(driver
, index
);
1873 tty_port_set_kopened(tty
->port
, 1);
1876 mutex_unlock(&tty_mutex
);
1877 tty_driver_kref_put(driver
);
1880 EXPORT_SYMBOL_GPL(tty_kopen
);
1883 * tty_open_by_driver - open a tty device
1884 * @device: dev_t of device to open
1885 * @inode: inode of device file
1886 * @filp: file pointer to tty
1888 * Performs the driver lookup, checks for a reopen, or otherwise
1889 * performs the first-time tty initialization.
1891 * Returns the locked initialized or re-opened &tty_struct
1893 * Claims the global tty_mutex to serialize:
1894 * - concurrent first-time tty initialization
1895 * - concurrent tty driver removal w/ lookup
1896 * - concurrent tty removal from driver table
1898 static struct tty_struct
*tty_open_by_driver(dev_t device
, struct inode
*inode
,
1901 struct tty_struct
*tty
;
1902 struct tty_driver
*driver
= NULL
;
1906 mutex_lock(&tty_mutex
);
1907 driver
= tty_lookup_driver(device
, filp
, &index
);
1908 if (IS_ERR(driver
)) {
1909 mutex_unlock(&tty_mutex
);
1910 return ERR_CAST(driver
);
1913 /* check whether we're reopening an existing tty */
1914 tty
= tty_driver_lookup_tty(driver
, filp
, index
);
1916 mutex_unlock(&tty_mutex
);
1921 if (tty_port_kopened(tty
->port
)) {
1923 mutex_unlock(&tty_mutex
);
1924 tty
= ERR_PTR(-EBUSY
);
1927 mutex_unlock(&tty_mutex
);
1928 retval
= tty_lock_interruptible(tty
);
1929 tty_kref_put(tty
); /* drop kref from tty_driver_lookup_tty() */
1931 if (retval
== -EINTR
)
1932 retval
= -ERESTARTSYS
;
1933 tty
= ERR_PTR(retval
);
1936 retval
= tty_reopen(tty
);
1939 tty
= ERR_PTR(retval
);
1941 } else { /* Returns with the tty_lock held for now */
1942 tty
= tty_init_dev(driver
, index
);
1943 mutex_unlock(&tty_mutex
);
1946 tty_driver_kref_put(driver
);
1951 * tty_open - open a tty device
1952 * @inode: inode of device file
1953 * @filp: file pointer to tty
1955 * tty_open and tty_release keep up the tty count that contains the
1956 * number of opens done on a tty. We cannot use the inode-count, as
1957 * different inodes might point to the same tty.
1959 * Open-counting is needed for pty masters, as well as for keeping
1960 * track of serial lines: DTR is dropped when the last close happens.
1961 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1963 * The termios state of a pty is reset on first open so that
1964 * settings don't persist across reuse.
1966 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
1967 * tty->count should protect the rest.
1968 * ->siglock protects ->signal/->sighand
1970 * Note: the tty_unlock/lock cases without a ref are only safe due to
1974 static int tty_open(struct inode
*inode
, struct file
*filp
)
1976 struct tty_struct
*tty
;
1978 dev_t device
= inode
->i_rdev
;
1979 unsigned saved_flags
= filp
->f_flags
;
1981 nonseekable_open(inode
, filp
);
1984 retval
= tty_alloc_file(filp
);
1988 tty
= tty_open_current_tty(device
, filp
);
1990 tty
= tty_open_by_driver(device
, inode
, filp
);
1993 tty_free_file(filp
);
1994 retval
= PTR_ERR(tty
);
1995 if (retval
!= -EAGAIN
|| signal_pending(current
))
2001 tty_add_file(tty
, filp
);
2003 check_tty_count(tty
, __func__
);
2004 tty_debug_hangup(tty
, "opening (count=%d)\n", tty
->count
);
2007 retval
= tty
->ops
->open(tty
, filp
);
2010 filp
->f_flags
= saved_flags
;
2013 tty_debug_hangup(tty
, "open error %d, releasing\n", retval
);
2015 tty_unlock(tty
); /* need to call tty_release without BTM */
2016 tty_release(inode
, filp
);
2017 if (retval
!= -ERESTARTSYS
)
2020 if (signal_pending(current
))
2025 * Need to reset f_op in case a hangup happened.
2027 if (tty_hung_up_p(filp
))
2028 filp
->f_op
= &tty_fops
;
2031 clear_bit(TTY_HUPPED
, &tty
->flags
);
2033 noctty
= (filp
->f_flags
& O_NOCTTY
) ||
2034 (IS_ENABLED(CONFIG_VT
) && device
== MKDEV(TTY_MAJOR
, 0)) ||
2035 device
== MKDEV(TTYAUX_MAJOR
, 1) ||
2036 (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2037 tty
->driver
->subtype
== PTY_TYPE_MASTER
);
2039 tty_open_proc_set_tty(filp
, tty
);
2047 * tty_poll - check tty status
2048 * @filp: file being polled
2049 * @wait: poll wait structures to update
2051 * Call the line discipline polling method to obtain the poll
2052 * status of the device.
2054 * Locking: locks called line discipline but ldisc poll method
2055 * may be re-entered freely by other callers.
2058 static unsigned int tty_poll(struct file
*filp
, poll_table
*wait
)
2060 struct tty_struct
*tty
= file_tty(filp
);
2061 struct tty_ldisc
*ld
;
2064 if (tty_paranoia_check(tty
, file_inode(filp
), "tty_poll"))
2067 ld
= tty_ldisc_ref_wait(tty
);
2069 return hung_up_tty_poll(filp
, wait
);
2071 ret
= ld
->ops
->poll(tty
, filp
, wait
);
2072 tty_ldisc_deref(ld
);
2076 static int __tty_fasync(int fd
, struct file
*filp
, int on
)
2078 struct tty_struct
*tty
= file_tty(filp
);
2079 unsigned long flags
;
2082 if (tty_paranoia_check(tty
, file_inode(filp
), "tty_fasync"))
2085 retval
= fasync_helper(fd
, filp
, on
, &tty
->fasync
);
2093 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2096 type
= PIDTYPE_PGID
;
2098 pid
= task_pid(current
);
2102 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2103 __f_setown(filp
, pid
, type
, 0);
2111 static int tty_fasync(int fd
, struct file
*filp
, int on
)
2113 struct tty_struct
*tty
= file_tty(filp
);
2114 int retval
= -ENOTTY
;
2117 if (!tty_hung_up_p(filp
))
2118 retval
= __tty_fasync(fd
, filp
, on
);
2125 * tiocsti - fake input character
2126 * @tty: tty to fake input into
2127 * @p: pointer to character
2129 * Fake input to a tty device. Does the necessary locking and
2132 * FIXME: does not honour flow control ??
2135 * Called functions take tty_ldiscs_lock
2136 * current->signal->tty check is safe without locks
2138 * FIXME: may race normal receive processing
2141 static int tiocsti(struct tty_struct
*tty
, char __user
*p
)
2144 struct tty_ldisc
*ld
;
2146 if ((current
->signal
->tty
!= tty
) && !capable(CAP_SYS_ADMIN
))
2148 if (get_user(ch
, p
))
2150 tty_audit_tiocsti(tty
, ch
);
2151 ld
= tty_ldisc_ref_wait(tty
);
2154 ld
->ops
->receive_buf(tty
, &ch
, &mbz
, 1);
2155 tty_ldisc_deref(ld
);
2160 * tiocgwinsz - implement window query ioctl
2162 * @arg: user buffer for result
2164 * Copies the kernel idea of the window size into the user buffer.
2166 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2170 static int tiocgwinsz(struct tty_struct
*tty
, struct winsize __user
*arg
)
2174 mutex_lock(&tty
->winsize_mutex
);
2175 err
= copy_to_user(arg
, &tty
->winsize
, sizeof(*arg
));
2176 mutex_unlock(&tty
->winsize_mutex
);
2178 return err
? -EFAULT
: 0;
2182 * tty_do_resize - resize event
2183 * @tty: tty being resized
2184 * @rows: rows (character)
2185 * @cols: cols (character)
2187 * Update the termios variables and send the necessary signals to
2188 * peform a terminal resize correctly
2191 int tty_do_resize(struct tty_struct
*tty
, struct winsize
*ws
)
2196 mutex_lock(&tty
->winsize_mutex
);
2197 if (!memcmp(ws
, &tty
->winsize
, sizeof(*ws
)))
2200 /* Signal the foreground process group */
2201 pgrp
= tty_get_pgrp(tty
);
2203 kill_pgrp(pgrp
, SIGWINCH
, 1);
2208 mutex_unlock(&tty
->winsize_mutex
);
2211 EXPORT_SYMBOL(tty_do_resize
);
2214 * tiocswinsz - implement window size set ioctl
2215 * @tty; tty side of tty
2216 * @arg: user buffer for result
2218 * Copies the user idea of the window size to the kernel. Traditionally
2219 * this is just advisory information but for the Linux console it
2220 * actually has driver level meaning and triggers a VC resize.
2223 * Driver dependent. The default do_resize method takes the
2224 * tty termios mutex and ctrl_lock. The console takes its own lock
2225 * then calls into the default method.
2228 static int tiocswinsz(struct tty_struct
*tty
, struct winsize __user
*arg
)
2230 struct winsize tmp_ws
;
2231 if (copy_from_user(&tmp_ws
, arg
, sizeof(*arg
)))
2234 if (tty
->ops
->resize
)
2235 return tty
->ops
->resize(tty
, &tmp_ws
);
2237 return tty_do_resize(tty
, &tmp_ws
);
2241 * tioccons - allow admin to move logical console
2242 * @file: the file to become console
2244 * Allow the administrator to move the redirected console device
2246 * Locking: uses redirect_lock to guard the redirect information
2249 static int tioccons(struct file
*file
)
2251 if (!capable(CAP_SYS_ADMIN
))
2253 if (file
->f_op
->write
== redirected_tty_write
) {
2255 spin_lock(&redirect_lock
);
2258 spin_unlock(&redirect_lock
);
2263 spin_lock(&redirect_lock
);
2265 spin_unlock(&redirect_lock
);
2268 redirect
= get_file(file
);
2269 spin_unlock(&redirect_lock
);
2274 * fionbio - non blocking ioctl
2275 * @file: file to set blocking value
2276 * @p: user parameter
2278 * Historical tty interfaces had a blocking control ioctl before
2279 * the generic functionality existed. This piece of history is preserved
2280 * in the expected tty API of posix OS's.
2282 * Locking: none, the open file handle ensures it won't go away.
2285 static int fionbio(struct file
*file
, int __user
*p
)
2289 if (get_user(nonblock
, p
))
2292 spin_lock(&file
->f_lock
);
2294 file
->f_flags
|= O_NONBLOCK
;
2296 file
->f_flags
&= ~O_NONBLOCK
;
2297 spin_unlock(&file
->f_lock
);
2302 * tiocsetd - set line discipline
2304 * @p: pointer to user data
2306 * Set the line discipline according to user request.
2308 * Locking: see tty_set_ldisc, this function is just a helper
2311 static int tiocsetd(struct tty_struct
*tty
, int __user
*p
)
2316 if (get_user(disc
, p
))
2319 ret
= tty_set_ldisc(tty
, disc
);
2325 * tiocgetd - get line discipline
2327 * @p: pointer to user data
2329 * Retrieves the line discipline id directly from the ldisc.
2331 * Locking: waits for ldisc reference (in case the line discipline
2332 * is changing or the tty is being hungup)
2335 static int tiocgetd(struct tty_struct
*tty
, int __user
*p
)
2337 struct tty_ldisc
*ld
;
2340 ld
= tty_ldisc_ref_wait(tty
);
2343 ret
= put_user(ld
->ops
->num
, p
);
2344 tty_ldisc_deref(ld
);
2349 * send_break - performed time break
2350 * @tty: device to break on
2351 * @duration: timeout in mS
2353 * Perform a timed break on hardware that lacks its own driver level
2354 * timed break functionality.
2357 * atomic_write_lock serializes
2361 static int send_break(struct tty_struct
*tty
, unsigned int duration
)
2365 if (tty
->ops
->break_ctl
== NULL
)
2368 if (tty
->driver
->flags
& TTY_DRIVER_HARDWARE_BREAK
)
2369 retval
= tty
->ops
->break_ctl(tty
, duration
);
2371 /* Do the work ourselves */
2372 if (tty_write_lock(tty
, 0) < 0)
2374 retval
= tty
->ops
->break_ctl(tty
, -1);
2377 if (!signal_pending(current
))
2378 msleep_interruptible(duration
);
2379 retval
= tty
->ops
->break_ctl(tty
, 0);
2381 tty_write_unlock(tty
);
2382 if (signal_pending(current
))
2389 * tty_tiocmget - get modem status
2391 * @file: user file pointer
2392 * @p: pointer to result
2394 * Obtain the modem status bits from the tty driver if the feature
2395 * is supported. Return -EINVAL if it is not available.
2397 * Locking: none (up to the driver)
2400 static int tty_tiocmget(struct tty_struct
*tty
, int __user
*p
)
2402 int retval
= -EINVAL
;
2404 if (tty
->ops
->tiocmget
) {
2405 retval
= tty
->ops
->tiocmget(tty
);
2408 retval
= put_user(retval
, p
);
2414 * tty_tiocmset - set modem status
2416 * @cmd: command - clear bits, set bits or set all
2417 * @p: pointer to desired bits
2419 * Set the modem status bits from the tty driver if the feature
2420 * is supported. Return -EINVAL if it is not available.
2422 * Locking: none (up to the driver)
2425 static int tty_tiocmset(struct tty_struct
*tty
, unsigned int cmd
,
2429 unsigned int set
, clear
, val
;
2431 if (tty
->ops
->tiocmset
== NULL
)
2434 retval
= get_user(val
, p
);
2450 set
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
2451 clear
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
2452 return tty
->ops
->tiocmset(tty
, set
, clear
);
2455 static int tty_tiocgicount(struct tty_struct
*tty
, void __user
*arg
)
2457 int retval
= -EINVAL
;
2458 struct serial_icounter_struct icount
;
2459 memset(&icount
, 0, sizeof(icount
));
2460 if (tty
->ops
->get_icount
)
2461 retval
= tty
->ops
->get_icount(tty
, &icount
);
2464 if (copy_to_user(arg
, &icount
, sizeof(icount
)))
2469 static void tty_warn_deprecated_flags(struct serial_struct __user
*ss
)
2471 static DEFINE_RATELIMIT_STATE(depr_flags
,
2472 DEFAULT_RATELIMIT_INTERVAL
,
2473 DEFAULT_RATELIMIT_BURST
);
2474 char comm
[TASK_COMM_LEN
];
2477 if (get_user(flags
, &ss
->flags
))
2480 flags
&= ASYNC_DEPRECATED
;
2482 if (flags
&& __ratelimit(&depr_flags
))
2483 pr_warn("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2484 __func__
, get_task_comm(comm
, current
), flags
);
2488 * if pty, return the slave side (real_tty)
2489 * otherwise, return self
2491 static struct tty_struct
*tty_pair_get_tty(struct tty_struct
*tty
)
2493 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2494 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
2500 * Split this up, as gcc can choke on it otherwise..
2502 long tty_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
2504 struct tty_struct
*tty
= file_tty(file
);
2505 struct tty_struct
*real_tty
;
2506 void __user
*p
= (void __user
*)arg
;
2508 struct tty_ldisc
*ld
;
2510 if (tty_paranoia_check(tty
, file_inode(file
), "tty_ioctl"))
2513 real_tty
= tty_pair_get_tty(tty
);
2516 * Factor out some common prep work
2524 retval
= tty_check_change(tty
);
2527 if (cmd
!= TIOCCBRK
) {
2528 tty_wait_until_sent(tty
, 0);
2529 if (signal_pending(current
))
2540 return tiocsti(tty
, p
);
2542 return tiocgwinsz(real_tty
, p
);
2544 return tiocswinsz(real_tty
, p
);
2546 return real_tty
!= tty
? -EINVAL
: tioccons(file
);
2548 return fionbio(file
, p
);
2550 set_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2553 clear_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2557 int excl
= test_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2558 return put_user(excl
, (int __user
*)p
);
2561 return tiocgetd(tty
, p
);
2563 return tiocsetd(tty
, p
);
2565 if (!capable(CAP_SYS_ADMIN
))
2571 unsigned int ret
= new_encode_dev(tty_devnum(real_tty
));
2572 return put_user(ret
, (unsigned int __user
*)p
);
2577 case TIOCSBRK
: /* Turn break on, unconditionally */
2578 if (tty
->ops
->break_ctl
)
2579 return tty
->ops
->break_ctl(tty
, -1);
2581 case TIOCCBRK
: /* Turn break off, unconditionally */
2582 if (tty
->ops
->break_ctl
)
2583 return tty
->ops
->break_ctl(tty
, 0);
2585 case TCSBRK
: /* SVID version: non-zero arg --> no break */
2586 /* non-zero arg means wait for all output data
2587 * to be sent (performed above) but don't send break.
2588 * This is used by the tcdrain() termios function.
2591 return send_break(tty
, 250);
2593 case TCSBRKP
: /* support for POSIX tcsendbreak() */
2594 return send_break(tty
, arg
? arg
*100 : 250);
2597 return tty_tiocmget(tty
, p
);
2601 return tty_tiocmset(tty
, cmd
, p
);
2603 retval
= tty_tiocgicount(tty
, p
);
2604 /* For the moment allow fall through to the old method */
2605 if (retval
!= -EINVAL
)
2612 /* flush tty buffer and allow ldisc to process ioctl */
2613 tty_buffer_flush(tty
, NULL
);
2618 tty_warn_deprecated_flags(p
);
2621 /* Special because the struct file is needed */
2622 return ptm_open_peer(file
, tty
, (int)arg
);
2624 retval
= tty_jobctrl_ioctl(tty
, real_tty
, file
, cmd
, arg
);
2625 if (retval
!= -ENOIOCTLCMD
)
2628 if (tty
->ops
->ioctl
) {
2629 retval
= tty
->ops
->ioctl(tty
, cmd
, arg
);
2630 if (retval
!= -ENOIOCTLCMD
)
2633 ld
= tty_ldisc_ref_wait(tty
);
2635 return hung_up_tty_ioctl(file
, cmd
, arg
);
2637 if (ld
->ops
->ioctl
) {
2638 retval
= ld
->ops
->ioctl(tty
, file
, cmd
, arg
);
2639 if (retval
== -ENOIOCTLCMD
)
2642 tty_ldisc_deref(ld
);
2646 #ifdef CONFIG_COMPAT
2647 static long tty_compat_ioctl(struct file
*file
, unsigned int cmd
,
2650 struct tty_struct
*tty
= file_tty(file
);
2651 struct tty_ldisc
*ld
;
2652 int retval
= -ENOIOCTLCMD
;
2654 if (tty_paranoia_check(tty
, file_inode(file
), "tty_ioctl"))
2657 if (tty
->ops
->compat_ioctl
) {
2658 retval
= tty
->ops
->compat_ioctl(tty
, cmd
, arg
);
2659 if (retval
!= -ENOIOCTLCMD
)
2663 ld
= tty_ldisc_ref_wait(tty
);
2665 return hung_up_tty_compat_ioctl(file
, cmd
, arg
);
2666 if (ld
->ops
->compat_ioctl
)
2667 retval
= ld
->ops
->compat_ioctl(tty
, file
, cmd
, arg
);
2669 retval
= n_tty_compat_ioctl_helper(tty
, file
, cmd
, arg
);
2670 tty_ldisc_deref(ld
);
2676 static int this_tty(const void *t
, struct file
*file
, unsigned fd
)
2678 if (likely(file
->f_op
->read
!= tty_read
))
2680 return file_tty(file
) != t
? 0 : fd
+ 1;
2684 * This implements the "Secure Attention Key" --- the idea is to
2685 * prevent trojan horses by killing all processes associated with this
2686 * tty when the user hits the "Secure Attention Key". Required for
2687 * super-paranoid applications --- see the Orange Book for more details.
2689 * This code could be nicer; ideally it should send a HUP, wait a few
2690 * seconds, then send a INT, and then a KILL signal. But you then
2691 * have to coordinate with the init process, since all processes associated
2692 * with the current tty must be dead before the new getty is allowed
2695 * Now, if it would be correct ;-/ The current code has a nasty hole -
2696 * it doesn't catch files in flight. We may send the descriptor to ourselves
2697 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2699 * Nasty bug: do_SAK is being called in interrupt context. This can
2700 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2702 void __do_SAK(struct tty_struct
*tty
)
2707 struct task_struct
*g
, *p
;
2708 struct pid
*session
;
2713 session
= tty
->session
;
2715 tty_ldisc_flush(tty
);
2717 tty_driver_flush_buffer(tty
);
2719 read_lock(&tasklist_lock
);
2720 /* Kill the entire session */
2721 do_each_pid_task(session
, PIDTYPE_SID
, p
) {
2722 tty_notice(tty
, "SAK: killed process %d (%s): by session\n",
2723 task_pid_nr(p
), p
->comm
);
2724 send_sig(SIGKILL
, p
, 1);
2725 } while_each_pid_task(session
, PIDTYPE_SID
, p
);
2727 /* Now kill any processes that happen to have the tty open */
2728 do_each_thread(g
, p
) {
2729 if (p
->signal
->tty
== tty
) {
2730 tty_notice(tty
, "SAK: killed process %d (%s): by controlling tty\n",
2731 task_pid_nr(p
), p
->comm
);
2732 send_sig(SIGKILL
, p
, 1);
2736 i
= iterate_fd(p
->files
, 0, this_tty
, tty
);
2738 tty_notice(tty
, "SAK: killed process %d (%s): by fd#%d\n",
2739 task_pid_nr(p
), p
->comm
, i
- 1);
2740 force_sig(SIGKILL
, p
);
2743 } while_each_thread(g
, p
);
2744 read_unlock(&tasklist_lock
);
2748 static void do_SAK_work(struct work_struct
*work
)
2750 struct tty_struct
*tty
=
2751 container_of(work
, struct tty_struct
, SAK_work
);
2756 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2757 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2758 * the values which we write to it will be identical to the values which it
2759 * already has. --akpm
2761 void do_SAK(struct tty_struct
*tty
)
2765 schedule_work(&tty
->SAK_work
);
2768 EXPORT_SYMBOL(do_SAK
);
2770 static int dev_match_devt(struct device
*dev
, const void *data
)
2772 const dev_t
*devt
= data
;
2773 return dev
->devt
== *devt
;
2776 /* Must put_device() after it's unused! */
2777 static struct device
*tty_get_device(struct tty_struct
*tty
)
2779 dev_t devt
= tty_devnum(tty
);
2780 return class_find_device(tty_class
, NULL
, &devt
, dev_match_devt
);
2787 * This subroutine allocates and initializes a tty structure.
2789 * Locking: none - tty in question is not exposed at this point
2792 struct tty_struct
*alloc_tty_struct(struct tty_driver
*driver
, int idx
)
2794 struct tty_struct
*tty
;
2796 tty
= kzalloc(sizeof(*tty
), GFP_KERNEL
);
2800 kref_init(&tty
->kref
);
2801 tty
->magic
= TTY_MAGIC
;
2802 tty_ldisc_init(tty
);
2803 tty
->session
= NULL
;
2805 mutex_init(&tty
->legacy_mutex
);
2806 mutex_init(&tty
->throttle_mutex
);
2807 init_rwsem(&tty
->termios_rwsem
);
2808 mutex_init(&tty
->winsize_mutex
);
2809 init_ldsem(&tty
->ldisc_sem
);
2810 init_waitqueue_head(&tty
->write_wait
);
2811 init_waitqueue_head(&tty
->read_wait
);
2812 INIT_WORK(&tty
->hangup_work
, do_tty_hangup
);
2813 mutex_init(&tty
->atomic_write_lock
);
2814 spin_lock_init(&tty
->ctrl_lock
);
2815 spin_lock_init(&tty
->flow_lock
);
2816 spin_lock_init(&tty
->files_lock
);
2817 INIT_LIST_HEAD(&tty
->tty_files
);
2818 INIT_WORK(&tty
->SAK_work
, do_SAK_work
);
2820 tty
->driver
= driver
;
2821 tty
->ops
= driver
->ops
;
2823 tty_line_name(driver
, idx
, tty
->name
);
2824 tty
->dev
= tty_get_device(tty
);
2830 * tty_put_char - write one character to a tty
2834 * Write one byte to the tty using the provided put_char method
2835 * if present. Returns the number of characters successfully output.
2837 * Note: the specific put_char operation in the driver layer may go
2838 * away soon. Don't call it directly, use this method
2841 int tty_put_char(struct tty_struct
*tty
, unsigned char ch
)
2843 if (tty
->ops
->put_char
)
2844 return tty
->ops
->put_char(tty
, ch
);
2845 return tty
->ops
->write(tty
, &ch
, 1);
2847 EXPORT_SYMBOL_GPL(tty_put_char
);
2849 struct class *tty_class
;
2851 static int tty_cdev_add(struct tty_driver
*driver
, dev_t dev
,
2852 unsigned int index
, unsigned int count
)
2856 /* init here, since reused cdevs cause crashes */
2857 driver
->cdevs
[index
] = cdev_alloc();
2858 if (!driver
->cdevs
[index
])
2860 driver
->cdevs
[index
]->ops
= &tty_fops
;
2861 driver
->cdevs
[index
]->owner
= driver
->owner
;
2862 err
= cdev_add(driver
->cdevs
[index
], dev
, count
);
2864 kobject_put(&driver
->cdevs
[index
]->kobj
);
2869 * tty_register_device - register a tty device
2870 * @driver: the tty driver that describes the tty device
2871 * @index: the index in the tty driver for this tty device
2872 * @device: a struct device that is associated with this tty device.
2873 * This field is optional, if there is no known struct device
2874 * for this tty device it can be set to NULL safely.
2876 * Returns a pointer to the struct device for this tty device
2877 * (or ERR_PTR(-EFOO) on error).
2879 * This call is required to be made to register an individual tty device
2880 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2881 * that bit is not set, this function should not be called by a tty
2887 struct device
*tty_register_device(struct tty_driver
*driver
, unsigned index
,
2888 struct device
*device
)
2890 return tty_register_device_attr(driver
, index
, device
, NULL
, NULL
);
2892 EXPORT_SYMBOL(tty_register_device
);
2894 static void tty_device_create_release(struct device
*dev
)
2896 dev_dbg(dev
, "releasing...\n");
2901 * tty_register_device_attr - register a tty device
2902 * @driver: the tty driver that describes the tty device
2903 * @index: the index in the tty driver for this tty device
2904 * @device: a struct device that is associated with this tty device.
2905 * This field is optional, if there is no known struct device
2906 * for this tty device it can be set to NULL safely.
2907 * @drvdata: Driver data to be set to device.
2908 * @attr_grp: Attribute group to be set on device.
2910 * Returns a pointer to the struct device for this tty device
2911 * (or ERR_PTR(-EFOO) on error).
2913 * This call is required to be made to register an individual tty device
2914 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2915 * that bit is not set, this function should not be called by a tty
2920 struct device
*tty_register_device_attr(struct tty_driver
*driver
,
2921 unsigned index
, struct device
*device
,
2923 const struct attribute_group
**attr_grp
)
2926 dev_t devt
= MKDEV(driver
->major
, driver
->minor_start
) + index
;
2927 struct ktermios
*tp
;
2931 if (index
>= driver
->num
) {
2932 pr_err("%s: Attempt to register invalid tty line number (%d)\n",
2933 driver
->name
, index
);
2934 return ERR_PTR(-EINVAL
);
2937 if (driver
->type
== TTY_DRIVER_TYPE_PTY
)
2938 pty_line_name(driver
, index
, name
);
2940 tty_line_name(driver
, index
, name
);
2942 dev
= kzalloc(sizeof(*dev
), GFP_KERNEL
);
2944 return ERR_PTR(-ENOMEM
);
2947 dev
->class = tty_class
;
2948 dev
->parent
= device
;
2949 dev
->release
= tty_device_create_release
;
2950 dev_set_name(dev
, "%s", name
);
2951 dev
->groups
= attr_grp
;
2952 dev_set_drvdata(dev
, drvdata
);
2954 dev_set_uevent_suppress(dev
, 1);
2956 retval
= device_register(dev
);
2960 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
)) {
2962 * Free any saved termios data so that the termios state is
2963 * reset when reusing a minor number.
2965 tp
= driver
->termios
[index
];
2967 driver
->termios
[index
] = NULL
;
2971 retval
= tty_cdev_add(driver
, devt
, index
, 1);
2976 dev_set_uevent_suppress(dev
, 0);
2977 kobject_uevent(&dev
->kobj
, KOBJ_ADD
);
2986 return ERR_PTR(retval
);
2988 EXPORT_SYMBOL_GPL(tty_register_device_attr
);
2991 * tty_unregister_device - unregister a tty device
2992 * @driver: the tty driver that describes the tty device
2993 * @index: the index in the tty driver for this tty device
2995 * If a tty device is registered with a call to tty_register_device() then
2996 * this function must be called when the tty device is gone.
3001 void tty_unregister_device(struct tty_driver
*driver
, unsigned index
)
3003 device_destroy(tty_class
,
3004 MKDEV(driver
->major
, driver
->minor_start
) + index
);
3005 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
)) {
3006 cdev_del(driver
->cdevs
[index
]);
3007 driver
->cdevs
[index
] = NULL
;
3010 EXPORT_SYMBOL(tty_unregister_device
);
3013 * __tty_alloc_driver -- allocate tty driver
3014 * @lines: count of lines this driver can handle at most
3015 * @owner: module which is responsible for this driver
3016 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3018 * This should not be called directly, some of the provided macros should be
3019 * used instead. Use IS_ERR and friends on @retval.
3021 struct tty_driver
*__tty_alloc_driver(unsigned int lines
, struct module
*owner
,
3022 unsigned long flags
)
3024 struct tty_driver
*driver
;
3025 unsigned int cdevs
= 1;
3028 if (!lines
|| (flags
& TTY_DRIVER_UNNUMBERED_NODE
&& lines
> 1))
3029 return ERR_PTR(-EINVAL
);
3031 driver
= kzalloc(sizeof(struct tty_driver
), GFP_KERNEL
);
3033 return ERR_PTR(-ENOMEM
);
3035 kref_init(&driver
->kref
);
3036 driver
->magic
= TTY_DRIVER_MAGIC
;
3037 driver
->num
= lines
;
3038 driver
->owner
= owner
;
3039 driver
->flags
= flags
;
3041 if (!(flags
& TTY_DRIVER_DEVPTS_MEM
)) {
3042 driver
->ttys
= kcalloc(lines
, sizeof(*driver
->ttys
),
3044 driver
->termios
= kcalloc(lines
, sizeof(*driver
->termios
),
3046 if (!driver
->ttys
|| !driver
->termios
) {
3052 if (!(flags
& TTY_DRIVER_DYNAMIC_ALLOC
)) {
3053 driver
->ports
= kcalloc(lines
, sizeof(*driver
->ports
),
3055 if (!driver
->ports
) {
3062 driver
->cdevs
= kcalloc(cdevs
, sizeof(*driver
->cdevs
), GFP_KERNEL
);
3063 if (!driver
->cdevs
) {
3070 kfree(driver
->ports
);
3071 kfree(driver
->ttys
);
3072 kfree(driver
->termios
);
3073 kfree(driver
->cdevs
);
3075 return ERR_PTR(err
);
3077 EXPORT_SYMBOL(__tty_alloc_driver
);
3079 static void destruct_tty_driver(struct kref
*kref
)
3081 struct tty_driver
*driver
= container_of(kref
, struct tty_driver
, kref
);
3083 struct ktermios
*tp
;
3085 if (driver
->flags
& TTY_DRIVER_INSTALLED
) {
3086 for (i
= 0; i
< driver
->num
; i
++) {
3087 tp
= driver
->termios
[i
];
3089 driver
->termios
[i
] = NULL
;
3092 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
))
3093 tty_unregister_device(driver
, i
);
3095 proc_tty_unregister_driver(driver
);
3096 if (driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
)
3097 cdev_del(driver
->cdevs
[0]);
3099 kfree(driver
->cdevs
);
3100 kfree(driver
->ports
);
3101 kfree(driver
->termios
);
3102 kfree(driver
->ttys
);
3106 void tty_driver_kref_put(struct tty_driver
*driver
)
3108 kref_put(&driver
->kref
, destruct_tty_driver
);
3110 EXPORT_SYMBOL(tty_driver_kref_put
);
3112 void tty_set_operations(struct tty_driver
*driver
,
3113 const struct tty_operations
*op
)
3117 EXPORT_SYMBOL(tty_set_operations
);
3119 void put_tty_driver(struct tty_driver
*d
)
3121 tty_driver_kref_put(d
);
3123 EXPORT_SYMBOL(put_tty_driver
);
3126 * Called by a tty driver to register itself.
3128 int tty_register_driver(struct tty_driver
*driver
)
3135 if (!driver
->major
) {
3136 error
= alloc_chrdev_region(&dev
, driver
->minor_start
,
3137 driver
->num
, driver
->name
);
3139 driver
->major
= MAJOR(dev
);
3140 driver
->minor_start
= MINOR(dev
);
3143 dev
= MKDEV(driver
->major
, driver
->minor_start
);
3144 error
= register_chrdev_region(dev
, driver
->num
, driver
->name
);
3149 if (driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
) {
3150 error
= tty_cdev_add(driver
, dev
, 0, driver
->num
);
3152 goto err_unreg_char
;
3155 mutex_lock(&tty_mutex
);
3156 list_add(&driver
->tty_drivers
, &tty_drivers
);
3157 mutex_unlock(&tty_mutex
);
3159 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
)) {
3160 for (i
= 0; i
< driver
->num
; i
++) {
3161 d
= tty_register_device(driver
, i
, NULL
);
3164 goto err_unreg_devs
;
3168 proc_tty_register_driver(driver
);
3169 driver
->flags
|= TTY_DRIVER_INSTALLED
;
3173 for (i
--; i
>= 0; i
--)
3174 tty_unregister_device(driver
, i
);
3176 mutex_lock(&tty_mutex
);
3177 list_del(&driver
->tty_drivers
);
3178 mutex_unlock(&tty_mutex
);
3181 unregister_chrdev_region(dev
, driver
->num
);
3185 EXPORT_SYMBOL(tty_register_driver
);
3188 * Called by a tty driver to unregister itself.
3190 int tty_unregister_driver(struct tty_driver
*driver
)
3194 if (driver
->refcount
)
3197 unregister_chrdev_region(MKDEV(driver
->major
, driver
->minor_start
),
3199 mutex_lock(&tty_mutex
);
3200 list_del(&driver
->tty_drivers
);
3201 mutex_unlock(&tty_mutex
);
3205 EXPORT_SYMBOL(tty_unregister_driver
);
3207 dev_t
tty_devnum(struct tty_struct
*tty
)
3209 return MKDEV(tty
->driver
->major
, tty
->driver
->minor_start
) + tty
->index
;
3211 EXPORT_SYMBOL(tty_devnum
);
3213 void tty_default_fops(struct file_operations
*fops
)
3218 static char *tty_devnode(struct device
*dev
, umode_t
*mode
)
3222 if (dev
->devt
== MKDEV(TTYAUX_MAJOR
, 0) ||
3223 dev
->devt
== MKDEV(TTYAUX_MAJOR
, 2))
3228 static int __init
tty_class_init(void)
3230 tty_class
= class_create(THIS_MODULE
, "tty");
3231 if (IS_ERR(tty_class
))
3232 return PTR_ERR(tty_class
);
3233 tty_class
->devnode
= tty_devnode
;
3237 postcore_initcall(tty_class_init
);
3239 /* 3/2004 jmc: why do these devices exist? */
3240 static struct cdev tty_cdev
, console_cdev
;
3242 static ssize_t
show_cons_active(struct device
*dev
,
3243 struct device_attribute
*attr
, char *buf
)
3245 struct console
*cs
[16];
3251 for_each_console(c
) {
3256 if ((c
->flags
& CON_ENABLED
) == 0)
3259 if (i
>= ARRAY_SIZE(cs
))
3263 int index
= cs
[i
]->index
;
3264 struct tty_driver
*drv
= cs
[i
]->device(cs
[i
], &index
);
3266 /* don't resolve tty0 as some programs depend on it */
3267 if (drv
&& (cs
[i
]->index
> 0 || drv
->major
!= TTY_MAJOR
))
3268 count
+= tty_line_name(drv
, index
, buf
+ count
);
3270 count
+= sprintf(buf
+ count
, "%s%d",
3271 cs
[i
]->name
, cs
[i
]->index
);
3273 count
+= sprintf(buf
+ count
, "%c", i
? ' ':'\n');
3279 static DEVICE_ATTR(active
, S_IRUGO
, show_cons_active
, NULL
);
3281 static struct attribute
*cons_dev_attrs
[] = {
3282 &dev_attr_active
.attr
,
3286 ATTRIBUTE_GROUPS(cons_dev
);
3288 static struct device
*consdev
;
3290 void console_sysfs_notify(void)
3293 sysfs_notify(&consdev
->kobj
, NULL
, "active");
3297 * Ok, now we can initialize the rest of the tty devices and can count
3298 * on memory allocations, interrupts etc..
3300 int __init
tty_init(void)
3302 cdev_init(&tty_cdev
, &tty_fops
);
3303 if (cdev_add(&tty_cdev
, MKDEV(TTYAUX_MAJOR
, 0), 1) ||
3304 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 0), 1, "/dev/tty") < 0)
3305 panic("Couldn't register /dev/tty driver\n");
3306 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 0), NULL
, "tty");
3308 cdev_init(&console_cdev
, &console_fops
);
3309 if (cdev_add(&console_cdev
, MKDEV(TTYAUX_MAJOR
, 1), 1) ||
3310 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 1), 1, "/dev/console") < 0)
3311 panic("Couldn't register /dev/console driver\n");
3312 consdev
= device_create_with_groups(tty_class
, NULL
,
3313 MKDEV(TTYAUX_MAJOR
, 1), NULL
,
3314 cons_dev_groups
, "console");
3315 if (IS_ERR(consdev
))
3319 vty_init(&console_fops
);