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 (!len
|| 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
)) {
590 * Some console devices aren't actually hung up for technical and
591 * historical reasons, which can lead to indefinite interruptible
592 * sleep in n_tty_read(). The following explicitly tells
593 * n_tty_read() to abort readers.
595 set_bit(TTY_HUPPING
, &tty
->flags
);
597 /* inuse_filps is protected by the single tty lock,
598 this really needs to change if we want to flush the
599 workqueue with the lock held */
600 check_tty_count(tty
, "tty_hangup");
602 spin_lock(&tty
->files_lock
);
603 /* This breaks for file handles being sent over AF_UNIX sockets ? */
604 list_for_each_entry(priv
, &tty
->tty_files
, list
) {
606 if (filp
->f_op
->write
== redirected_tty_write
)
608 if (filp
->f_op
->write
!= tty_write
)
611 __tty_fasync(-1, filp
, 0); /* can't block */
612 filp
->f_op
= &hung_up_tty_fops
;
614 spin_unlock(&tty
->files_lock
);
616 refs
= tty_signal_session_leader(tty
, exit_session
);
617 /* Account for the p->signal references we killed */
621 tty_ldisc_hangup(tty
, cons_filp
!= NULL
);
623 spin_lock_irq(&tty
->ctrl_lock
);
624 clear_bit(TTY_THROTTLED
, &tty
->flags
);
625 clear_bit(TTY_DO_WRITE_WAKEUP
, &tty
->flags
);
626 put_pid(tty
->session
);
630 tty
->ctrl_status
= 0;
631 spin_unlock_irq(&tty
->ctrl_lock
);
634 * If one of the devices matches a console pointer, we
635 * cannot just call hangup() because that will cause
636 * tty->count and state->count to go out of sync.
637 * So we just call close() the right number of times.
641 for (n
= 0; n
< closecount
; n
++)
642 tty
->ops
->close(tty
, cons_filp
);
643 } else if (tty
->ops
->hangup
)
644 tty
->ops
->hangup(tty
);
646 * We don't want to have driver/ldisc interactions beyond the ones
647 * we did here. The driver layer expects no calls after ->hangup()
648 * from the ldisc side, which is now guaranteed.
650 set_bit(TTY_HUPPED
, &tty
->flags
);
651 clear_bit(TTY_HUPPING
, &tty
->flags
);
658 static void do_tty_hangup(struct work_struct
*work
)
660 struct tty_struct
*tty
=
661 container_of(work
, struct tty_struct
, hangup_work
);
663 __tty_hangup(tty
, 0);
667 * tty_hangup - trigger a hangup event
668 * @tty: tty to hangup
670 * A carrier loss (virtual or otherwise) has occurred on this like
671 * schedule a hangup sequence to run after this event.
674 void tty_hangup(struct tty_struct
*tty
)
676 tty_debug_hangup(tty
, "hangup\n");
677 schedule_work(&tty
->hangup_work
);
680 EXPORT_SYMBOL(tty_hangup
);
683 * tty_vhangup - process vhangup
684 * @tty: tty to hangup
686 * The user has asked via system call for the terminal to be hung up.
687 * We do this synchronously so that when the syscall returns the process
688 * is complete. That guarantee is necessary for security reasons.
691 void tty_vhangup(struct tty_struct
*tty
)
693 tty_debug_hangup(tty
, "vhangup\n");
694 __tty_hangup(tty
, 0);
697 EXPORT_SYMBOL(tty_vhangup
);
701 * tty_vhangup_self - process vhangup for own ctty
703 * Perform a vhangup on the current controlling tty
706 void tty_vhangup_self(void)
708 struct tty_struct
*tty
;
710 tty
= get_current_tty();
718 * tty_vhangup_session - hangup session leader exit
719 * @tty: tty to hangup
721 * The session leader is exiting and hanging up its controlling terminal.
722 * Every process in the foreground process group is signalled SIGHUP.
724 * We do this synchronously so that when the syscall returns the process
725 * is complete. That guarantee is necessary for security reasons.
728 void tty_vhangup_session(struct tty_struct
*tty
)
730 tty_debug_hangup(tty
, "session hangup\n");
731 __tty_hangup(tty
, 1);
735 * tty_hung_up_p - was tty hung up
736 * @filp: file pointer of tty
738 * Return true if the tty has been subject to a vhangup or a carrier
742 int tty_hung_up_p(struct file
*filp
)
744 return (filp
&& filp
->f_op
== &hung_up_tty_fops
);
747 EXPORT_SYMBOL(tty_hung_up_p
);
750 * stop_tty - propagate flow control
753 * Perform flow control to the driver. May be called
754 * on an already stopped device and will not re-call the driver
757 * This functionality is used by both the line disciplines for
758 * halting incoming flow and by the driver. It may therefore be
759 * called from any context, may be under the tty atomic_write_lock
766 void __stop_tty(struct tty_struct
*tty
)
775 void stop_tty(struct tty_struct
*tty
)
779 spin_lock_irqsave(&tty
->flow_lock
, flags
);
781 spin_unlock_irqrestore(&tty
->flow_lock
, flags
);
783 EXPORT_SYMBOL(stop_tty
);
786 * start_tty - propagate flow control
789 * Start a tty that has been stopped if at all possible. If this
790 * tty was previous stopped and is now being started, the driver
791 * start method is invoked and the line discipline woken.
797 void __start_tty(struct tty_struct
*tty
)
799 if (!tty
->stopped
|| tty
->flow_stopped
)
803 tty
->ops
->start(tty
);
807 void start_tty(struct tty_struct
*tty
)
811 spin_lock_irqsave(&tty
->flow_lock
, flags
);
813 spin_unlock_irqrestore(&tty
->flow_lock
, flags
);
815 EXPORT_SYMBOL(start_tty
);
817 static void tty_update_time(struct timespec
*time
)
819 unsigned long sec
= get_seconds();
822 * We only care if the two values differ in anything other than the
823 * lower three bits (i.e every 8 seconds). If so, then we can update
824 * the time of the tty device, otherwise it could be construded as a
825 * security leak to let userspace know the exact timing of the tty.
827 if ((sec
^ time
->tv_sec
) & ~7)
832 * tty_read - read method for tty device files
833 * @file: pointer to tty file
835 * @count: size of user buffer
838 * Perform the read system call function on this terminal device. Checks
839 * for hung up devices before calling the line discipline method.
842 * Locks the line discipline internally while needed. Multiple
843 * read calls may be outstanding in parallel.
846 static ssize_t
tty_read(struct file
*file
, char __user
*buf
, size_t count
,
850 struct inode
*inode
= file_inode(file
);
851 struct tty_struct
*tty
= file_tty(file
);
852 struct tty_ldisc
*ld
;
854 if (tty_paranoia_check(tty
, inode
, "tty_read"))
856 if (!tty
|| tty_io_error(tty
))
859 /* We want to wait for the line discipline to sort out in this
861 ld
= tty_ldisc_ref_wait(tty
);
863 return hung_up_tty_read(file
, buf
, count
, ppos
);
865 i
= ld
->ops
->read(tty
, file
, buf
, count
);
871 tty_update_time(&inode
->i_atime
);
876 static void tty_write_unlock(struct tty_struct
*tty
)
878 mutex_unlock(&tty
->atomic_write_lock
);
879 wake_up_interruptible_poll(&tty
->write_wait
, POLLOUT
);
882 static int tty_write_lock(struct tty_struct
*tty
, int ndelay
)
884 if (!mutex_trylock(&tty
->atomic_write_lock
)) {
887 if (mutex_lock_interruptible(&tty
->atomic_write_lock
))
894 * Split writes up in sane blocksizes to avoid
895 * denial-of-service type attacks
897 static inline ssize_t
do_tty_write(
898 ssize_t (*write
)(struct tty_struct
*, struct file
*, const unsigned char *, size_t),
899 struct tty_struct
*tty
,
901 const char __user
*buf
,
904 ssize_t ret
, written
= 0;
907 ret
= tty_write_lock(tty
, file
->f_flags
& O_NDELAY
);
912 * We chunk up writes into a temporary buffer. This
913 * simplifies low-level drivers immensely, since they
914 * don't have locking issues and user mode accesses.
916 * But if TTY_NO_WRITE_SPLIT is set, we should use a
919 * The default chunk-size is 2kB, because the NTTY
920 * layer has problems with bigger chunks. It will
921 * claim to be able to handle more characters than
924 * FIXME: This can probably go away now except that 64K chunks
925 * are too likely to fail unless switched to vmalloc...
928 if (test_bit(TTY_NO_WRITE_SPLIT
, &tty
->flags
))
933 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
934 if (tty
->write_cnt
< chunk
) {
935 unsigned char *buf_chunk
;
940 buf_chunk
= kmalloc(chunk
, GFP_KERNEL
);
945 kfree(tty
->write_buf
);
946 tty
->write_cnt
= chunk
;
947 tty
->write_buf
= buf_chunk
;
950 /* Do the write .. */
956 if (copy_from_user(tty
->write_buf
, buf
, size
))
958 ret
= write(tty
, file
, tty
->write_buf
, size
);
967 if (signal_pending(current
))
972 tty_update_time(&file_inode(file
)->i_mtime
);
976 tty_write_unlock(tty
);
981 * tty_write_message - write a message to a certain tty, not just the console.
982 * @tty: the destination tty_struct
983 * @msg: the message to write
985 * This is used for messages that need to be redirected to a specific tty.
986 * We don't put it into the syslog queue right now maybe in the future if
989 * We must still hold the BTM and test the CLOSING flag for the moment.
992 void tty_write_message(struct tty_struct
*tty
, char *msg
)
995 mutex_lock(&tty
->atomic_write_lock
);
997 if (tty
->ops
->write
&& tty
->count
> 0)
998 tty
->ops
->write(tty
, msg
, strlen(msg
));
1000 tty_write_unlock(tty
);
1007 * tty_write - write method for tty device file
1008 * @file: tty file pointer
1009 * @buf: user data to write
1010 * @count: bytes to write
1013 * Write data to a tty device via the line discipline.
1016 * Locks the line discipline as required
1017 * Writes to the tty driver are serialized by the atomic_write_lock
1018 * and are then processed in chunks to the device. The line discipline
1019 * write method will not be invoked in parallel for each device.
1022 static ssize_t
tty_write(struct file
*file
, const char __user
*buf
,
1023 size_t count
, loff_t
*ppos
)
1025 struct tty_struct
*tty
= file_tty(file
);
1026 struct tty_ldisc
*ld
;
1029 if (tty_paranoia_check(tty
, file_inode(file
), "tty_write"))
1031 if (!tty
|| !tty
->ops
->write
|| tty_io_error(tty
))
1033 /* Short term debug to catch buggy drivers */
1034 if (tty
->ops
->write_room
== NULL
)
1035 tty_err(tty
, "missing write_room method\n");
1036 ld
= tty_ldisc_ref_wait(tty
);
1038 return hung_up_tty_write(file
, buf
, count
, ppos
);
1039 if (!ld
->ops
->write
)
1042 ret
= do_tty_write(ld
->ops
->write
, tty
, file
, buf
, count
);
1043 tty_ldisc_deref(ld
);
1047 ssize_t
redirected_tty_write(struct file
*file
, const char __user
*buf
,
1048 size_t count
, loff_t
*ppos
)
1050 struct file
*p
= NULL
;
1052 spin_lock(&redirect_lock
);
1054 p
= get_file(redirect
);
1055 spin_unlock(&redirect_lock
);
1059 res
= vfs_write(p
, buf
, count
, &p
->f_pos
);
1063 return tty_write(file
, buf
, count
, ppos
);
1067 * tty_send_xchar - send priority character
1069 * Send a high priority character to the tty even if stopped
1071 * Locking: none for xchar method, write ordering for write method.
1074 int tty_send_xchar(struct tty_struct
*tty
, char ch
)
1076 int was_stopped
= tty
->stopped
;
1078 if (tty
->ops
->send_xchar
) {
1079 down_read(&tty
->termios_rwsem
);
1080 tty
->ops
->send_xchar(tty
, ch
);
1081 up_read(&tty
->termios_rwsem
);
1085 if (tty_write_lock(tty
, 0) < 0)
1086 return -ERESTARTSYS
;
1088 down_read(&tty
->termios_rwsem
);
1091 tty
->ops
->write(tty
, &ch
, 1);
1094 up_read(&tty
->termios_rwsem
);
1095 tty_write_unlock(tty
);
1099 static char ptychar
[] = "pqrstuvwxyzabcde";
1102 * pty_line_name - generate name for a pty
1103 * @driver: the tty driver in use
1104 * @index: the minor number
1105 * @p: output buffer of at least 6 bytes
1107 * Generate a name from a driver reference and write it to the output
1112 static void pty_line_name(struct tty_driver
*driver
, int index
, char *p
)
1114 int i
= index
+ driver
->name_base
;
1115 /* ->name is initialized to "ttyp", but "tty" is expected */
1116 sprintf(p
, "%s%c%x",
1117 driver
->subtype
== PTY_TYPE_SLAVE
? "tty" : driver
->name
,
1118 ptychar
[i
>> 4 & 0xf], i
& 0xf);
1122 * tty_line_name - generate name for a tty
1123 * @driver: the tty driver in use
1124 * @index: the minor number
1125 * @p: output buffer of at least 7 bytes
1127 * Generate a name from a driver reference and write it to the output
1132 static ssize_t
tty_line_name(struct tty_driver
*driver
, int index
, char *p
)
1134 if (driver
->flags
& TTY_DRIVER_UNNUMBERED_NODE
)
1135 return sprintf(p
, "%s", driver
->name
);
1137 return sprintf(p
, "%s%d", driver
->name
,
1138 index
+ driver
->name_base
);
1142 * tty_driver_lookup_tty() - find an existing tty, if any
1143 * @driver: the driver for the tty
1144 * @idx: the minor number
1146 * Return the tty, if found. If not found, return NULL or ERR_PTR() if the
1147 * driver lookup() method returns an error.
1149 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1151 static struct tty_struct
*tty_driver_lookup_tty(struct tty_driver
*driver
,
1152 struct file
*file
, int idx
)
1154 struct tty_struct
*tty
;
1156 if (driver
->ops
->lookup
)
1158 tty
= ERR_PTR(-EIO
);
1160 tty
= driver
->ops
->lookup(driver
, file
, idx
);
1162 tty
= driver
->ttys
[idx
];
1170 * tty_init_termios - helper for termios setup
1171 * @tty: the tty to set up
1173 * Initialise the termios structures for this tty. Thus runs under
1174 * the tty_mutex currently so we can be relaxed about ordering.
1177 void tty_init_termios(struct tty_struct
*tty
)
1179 struct ktermios
*tp
;
1180 int idx
= tty
->index
;
1182 if (tty
->driver
->flags
& TTY_DRIVER_RESET_TERMIOS
)
1183 tty
->termios
= tty
->driver
->init_termios
;
1185 /* Check for lazy saved data */
1186 tp
= tty
->driver
->termios
[idx
];
1189 tty
->termios
.c_line
= tty
->driver
->init_termios
.c_line
;
1191 tty
->termios
= tty
->driver
->init_termios
;
1193 /* Compatibility until drivers always set this */
1194 tty
->termios
.c_ispeed
= tty_termios_input_baud_rate(&tty
->termios
);
1195 tty
->termios
.c_ospeed
= tty_termios_baud_rate(&tty
->termios
);
1197 EXPORT_SYMBOL_GPL(tty_init_termios
);
1199 int tty_standard_install(struct tty_driver
*driver
, struct tty_struct
*tty
)
1201 tty_init_termios(tty
);
1202 tty_driver_kref_get(driver
);
1204 driver
->ttys
[tty
->index
] = tty
;
1207 EXPORT_SYMBOL_GPL(tty_standard_install
);
1210 * tty_driver_install_tty() - install a tty entry in the driver
1211 * @driver: the driver for the tty
1214 * Install a tty object into the driver tables. The tty->index field
1215 * will be set by the time this is called. This method is responsible
1216 * for ensuring any need additional structures are allocated and
1219 * Locking: tty_mutex for now
1221 static int tty_driver_install_tty(struct tty_driver
*driver
,
1222 struct tty_struct
*tty
)
1224 return driver
->ops
->install
? driver
->ops
->install(driver
, tty
) :
1225 tty_standard_install(driver
, tty
);
1229 * tty_driver_remove_tty() - remove a tty from the driver tables
1230 * @driver: the driver for the tty
1231 * @idx: the minor number
1233 * Remvoe a tty object from the driver tables. The tty->index field
1234 * will be set by the time this is called.
1236 * Locking: tty_mutex for now
1238 static void tty_driver_remove_tty(struct tty_driver
*driver
, struct tty_struct
*tty
)
1240 if (driver
->ops
->remove
)
1241 driver
->ops
->remove(driver
, tty
);
1243 driver
->ttys
[tty
->index
] = NULL
;
1247 * tty_reopen() - fast re-open of an open tty
1248 * @tty - the tty to open
1250 * Return 0 on success, -errno on error.
1251 * Re-opens on master ptys are not allowed and return -EIO.
1253 * Locking: Caller must hold tty_lock
1255 static int tty_reopen(struct tty_struct
*tty
)
1257 struct tty_driver
*driver
= tty
->driver
;
1258 struct tty_ldisc
*ld
;
1261 if (driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1262 driver
->subtype
== PTY_TYPE_MASTER
)
1268 if (test_bit(TTY_EXCLUSIVE
, &tty
->flags
) && !capable(CAP_SYS_ADMIN
))
1271 ld
= tty_ldisc_ref_wait(tty
);
1273 tty_ldisc_deref(ld
);
1275 retval
= tty_ldisc_lock(tty
, 5 * HZ
);
1280 retval
= tty_ldisc_reinit(tty
, tty
->termios
.c_line
);
1281 tty_ldisc_unlock(tty
);
1291 * tty_init_dev - initialise a tty device
1292 * @driver: tty driver we are opening a device on
1293 * @idx: device index
1294 * @ret_tty: returned tty structure
1296 * Prepare a tty device. This may not be a "new" clean device but
1297 * could also be an active device. The pty drivers require special
1298 * handling because of this.
1301 * The function is called under the tty_mutex, which
1302 * protects us from the tty struct or driver itself going away.
1304 * On exit the tty device has the line discipline attached and
1305 * a reference count of 1. If a pair was created for pty/tty use
1306 * and the other was a pty master then it too has a reference count of 1.
1308 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1309 * failed open. The new code protects the open with a mutex, so it's
1310 * really quite straightforward. The mutex locking can probably be
1311 * relaxed for the (most common) case of reopening a tty.
1314 struct tty_struct
*tty_init_dev(struct tty_driver
*driver
, int idx
)
1316 struct tty_struct
*tty
;
1320 * First time open is complex, especially for PTY devices.
1321 * This code guarantees that either everything succeeds and the
1322 * TTY is ready for operation, or else the table slots are vacated
1323 * and the allocated memory released. (Except that the termios
1327 if (!try_module_get(driver
->owner
))
1328 return ERR_PTR(-ENODEV
);
1330 tty
= alloc_tty_struct(driver
, idx
);
1333 goto err_module_put
;
1337 retval
= tty_driver_install_tty(driver
, tty
);
1342 tty
->port
= driver
->ports
[idx
];
1344 WARN_RATELIMIT(!tty
->port
,
1345 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1346 __func__
, tty
->driver
->name
);
1348 retval
= tty_ldisc_lock(tty
, 5 * HZ
);
1350 goto err_release_lock
;
1351 tty
->port
->itty
= tty
;
1354 * Structures all installed ... call the ldisc open routines.
1355 * If we fail here just call release_tty to clean up. No need
1356 * to decrement the use counts, as release_tty doesn't care.
1358 retval
= tty_ldisc_setup(tty
, tty
->link
);
1360 goto err_release_tty
;
1361 tty_ldisc_unlock(tty
);
1362 /* Return the tty locked so that it cannot vanish under the caller */
1367 free_tty_struct(tty
);
1369 module_put(driver
->owner
);
1370 return ERR_PTR(retval
);
1372 /* call the tty release_tty routine to clean out this slot */
1374 tty_ldisc_unlock(tty
);
1375 tty_info_ratelimited(tty
, "ldisc open failed (%d), clearing slot %d\n",
1379 release_tty(tty
, idx
);
1380 return ERR_PTR(retval
);
1384 * tty_save_termios() - save tty termios data in driver table
1385 * @tty: tty whose termios data to save
1387 * Locking: Caller guarantees serialisation with tty_init_termios().
1389 void tty_save_termios(struct tty_struct
*tty
)
1391 struct ktermios
*tp
;
1392 int idx
= tty
->index
;
1394 /* If the port is going to reset then it has no termios to save */
1395 if (tty
->driver
->flags
& TTY_DRIVER_RESET_TERMIOS
)
1398 /* Stash the termios data */
1399 tp
= tty
->driver
->termios
[idx
];
1401 tp
= kmalloc(sizeof(struct ktermios
), GFP_KERNEL
);
1404 tty
->driver
->termios
[idx
] = tp
;
1408 EXPORT_SYMBOL_GPL(tty_save_termios
);
1411 * tty_flush_works - flush all works of a tty/pty pair
1412 * @tty: tty device to flush works for (or either end of a pty pair)
1414 * Sync flush all works belonging to @tty (and the 'other' tty).
1416 static void tty_flush_works(struct tty_struct
*tty
)
1418 flush_work(&tty
->SAK_work
);
1419 flush_work(&tty
->hangup_work
);
1421 flush_work(&tty
->link
->SAK_work
);
1422 flush_work(&tty
->link
->hangup_work
);
1427 * release_one_tty - release tty structure memory
1428 * @kref: kref of tty we are obliterating
1430 * Releases memory associated with a tty structure, and clears out the
1431 * driver table slots. This function is called when a device is no longer
1432 * in use. It also gets called when setup of a device fails.
1435 * takes the file list lock internally when working on the list
1436 * of ttys that the driver keeps.
1438 * This method gets called from a work queue so that the driver private
1439 * cleanup ops can sleep (needed for USB at least)
1441 static void release_one_tty(struct work_struct
*work
)
1443 struct tty_struct
*tty
=
1444 container_of(work
, struct tty_struct
, hangup_work
);
1445 struct tty_driver
*driver
= tty
->driver
;
1446 struct module
*owner
= driver
->owner
;
1448 if (tty
->ops
->cleanup
)
1449 tty
->ops
->cleanup(tty
);
1452 tty_driver_kref_put(driver
);
1455 spin_lock(&tty
->files_lock
);
1456 list_del_init(&tty
->tty_files
);
1457 spin_unlock(&tty
->files_lock
);
1460 put_pid(tty
->session
);
1461 free_tty_struct(tty
);
1464 static void queue_release_one_tty(struct kref
*kref
)
1466 struct tty_struct
*tty
= container_of(kref
, struct tty_struct
, kref
);
1468 /* The hangup queue is now free so we can reuse it rather than
1469 waste a chunk of memory for each port */
1470 INIT_WORK(&tty
->hangup_work
, release_one_tty
);
1471 schedule_work(&tty
->hangup_work
);
1475 * tty_kref_put - release a tty kref
1478 * Release a reference to a tty device and if need be let the kref
1479 * layer destruct the object for us
1482 void tty_kref_put(struct tty_struct
*tty
)
1485 kref_put(&tty
->kref
, queue_release_one_tty
);
1487 EXPORT_SYMBOL(tty_kref_put
);
1490 * release_tty - release tty structure memory
1492 * Release both @tty and a possible linked partner (think pty pair),
1493 * and decrement the refcount of the backing module.
1497 * takes the file list lock internally when working on the list
1498 * of ttys that the driver keeps.
1501 static void release_tty(struct tty_struct
*tty
, int idx
)
1503 /* This should always be true but check for the moment */
1504 WARN_ON(tty
->index
!= idx
);
1505 WARN_ON(!mutex_is_locked(&tty_mutex
));
1506 if (tty
->ops
->shutdown
)
1507 tty
->ops
->shutdown(tty
);
1508 tty_save_termios(tty
);
1509 tty_driver_remove_tty(tty
->driver
, tty
);
1510 tty
->port
->itty
= NULL
;
1512 tty
->link
->port
->itty
= NULL
;
1513 tty_buffer_cancel_work(tty
->port
);
1515 tty_buffer_cancel_work(tty
->link
->port
);
1517 tty_kref_put(tty
->link
);
1522 * tty_release_checks - check a tty before real release
1523 * @tty: tty to check
1524 * @o_tty: link of @tty (if any)
1525 * @idx: index of the tty
1527 * Performs some paranoid checking before true release of the @tty.
1528 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1530 static int tty_release_checks(struct tty_struct
*tty
, int idx
)
1532 #ifdef TTY_PARANOIA_CHECK
1533 if (idx
< 0 || idx
>= tty
->driver
->num
) {
1534 tty_debug(tty
, "bad idx %d\n", idx
);
1538 /* not much to check for devpts */
1539 if (tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
)
1542 if (tty
!= tty
->driver
->ttys
[idx
]) {
1543 tty_debug(tty
, "bad driver table[%d] = %p\n",
1544 idx
, tty
->driver
->ttys
[idx
]);
1547 if (tty
->driver
->other
) {
1548 struct tty_struct
*o_tty
= tty
->link
;
1550 if (o_tty
!= tty
->driver
->other
->ttys
[idx
]) {
1551 tty_debug(tty
, "bad other table[%d] = %p\n",
1552 idx
, tty
->driver
->other
->ttys
[idx
]);
1555 if (o_tty
->link
!= tty
) {
1556 tty_debug(tty
, "bad link = %p\n", o_tty
->link
);
1565 * tty_kclose - closes tty opened by tty_kopen
1568 * Performs the final steps to release and free a tty device. It is the
1569 * same as tty_release_struct except that it also resets TTY_PORT_KOPENED
1570 * flag on tty->port.
1572 void tty_kclose(struct tty_struct
*tty
)
1575 * Ask the line discipline code to release its structures
1577 tty_ldisc_release(tty
);
1579 /* Wait for pending work before tty destruction commmences */
1580 tty_flush_works(tty
);
1582 tty_debug_hangup(tty
, "freeing structure\n");
1584 * The release_tty function takes care of the details of clearing
1585 * the slots and preserving the termios structure. The tty_unlock_pair
1586 * should be safe as we keep a kref while the tty is locked (so the
1587 * unlock never unlocks a freed tty).
1589 mutex_lock(&tty_mutex
);
1590 tty_port_set_kopened(tty
->port
, 0);
1591 release_tty(tty
, tty
->index
);
1592 mutex_unlock(&tty_mutex
);
1594 EXPORT_SYMBOL_GPL(tty_kclose
);
1597 * tty_release_struct - release a tty struct
1599 * @idx: index of the tty
1601 * Performs the final steps to release and free a tty device. It is
1602 * roughly the reverse of tty_init_dev.
1604 void tty_release_struct(struct tty_struct
*tty
, int idx
)
1607 * Ask the line discipline code to release its structures
1609 tty_ldisc_release(tty
);
1611 /* Wait for pending work before tty destruction commmences */
1612 tty_flush_works(tty
);
1614 tty_debug_hangup(tty
, "freeing structure\n");
1616 * The release_tty function takes care of the details of clearing
1617 * the slots and preserving the termios structure. The tty_unlock_pair
1618 * should be safe as we keep a kref while the tty is locked (so the
1619 * unlock never unlocks a freed tty).
1621 mutex_lock(&tty_mutex
);
1622 release_tty(tty
, idx
);
1623 mutex_unlock(&tty_mutex
);
1625 EXPORT_SYMBOL_GPL(tty_release_struct
);
1628 * tty_release - vfs callback for close
1629 * @inode: inode of tty
1630 * @filp: file pointer for handle to tty
1632 * Called the last time each file handle is closed that references
1633 * this tty. There may however be several such references.
1636 * Takes bkl. See tty_release_dev
1638 * Even releasing the tty structures is a tricky business.. We have
1639 * to be very careful that the structures are all released at the
1640 * same time, as interrupts might otherwise get the wrong pointers.
1642 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1643 * lead to double frees or releasing memory still in use.
1646 int tty_release(struct inode
*inode
, struct file
*filp
)
1648 struct tty_struct
*tty
= file_tty(filp
);
1649 struct tty_struct
*o_tty
= NULL
;
1650 int do_sleep
, final
;
1655 if (tty_paranoia_check(tty
, inode
, __func__
))
1659 check_tty_count(tty
, __func__
);
1661 __tty_fasync(-1, filp
, 0);
1664 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1665 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
1668 if (tty_release_checks(tty
, idx
)) {
1673 tty_debug_hangup(tty
, "releasing (count=%d)\n", tty
->count
);
1675 if (tty
->ops
->close
)
1676 tty
->ops
->close(tty
, filp
);
1678 /* If tty is pty master, lock the slave pty (stable lock order) */
1679 tty_lock_slave(o_tty
);
1682 * Sanity check: if tty->count is going to zero, there shouldn't be
1683 * any waiters on tty->read_wait or tty->write_wait. We test the
1684 * wait queues and kick everyone out _before_ actually starting to
1685 * close. This ensures that we won't block while releasing the tty
1688 * The test for the o_tty closing is necessary, since the master and
1689 * slave sides may close in any order. If the slave side closes out
1690 * first, its count will be one, since the master side holds an open.
1691 * Thus this test wouldn't be triggered at the time the slave closed,
1697 if (tty
->count
<= 1) {
1698 if (waitqueue_active(&tty
->read_wait
)) {
1699 wake_up_poll(&tty
->read_wait
, POLLIN
);
1702 if (waitqueue_active(&tty
->write_wait
)) {
1703 wake_up_poll(&tty
->write_wait
, POLLOUT
);
1707 if (o_tty
&& o_tty
->count
<= 1) {
1708 if (waitqueue_active(&o_tty
->read_wait
)) {
1709 wake_up_poll(&o_tty
->read_wait
, POLLIN
);
1712 if (waitqueue_active(&o_tty
->write_wait
)) {
1713 wake_up_poll(&o_tty
->write_wait
, POLLOUT
);
1722 tty_warn(tty
, "read/write wait queue active!\n");
1724 schedule_timeout_killable(timeout
);
1725 if (timeout
< 120 * HZ
)
1726 timeout
= 2 * timeout
+ 1;
1728 timeout
= MAX_SCHEDULE_TIMEOUT
;
1732 if (--o_tty
->count
< 0) {
1733 tty_warn(tty
, "bad slave count (%d)\n", o_tty
->count
);
1737 if (--tty
->count
< 0) {
1738 tty_warn(tty
, "bad tty->count (%d)\n", tty
->count
);
1743 * We've decremented tty->count, so we need to remove this file
1744 * descriptor off the tty->tty_files list; this serves two
1746 * - check_tty_count sees the correct number of file descriptors
1747 * associated with this tty.
1748 * - do_tty_hangup no longer sees this file descriptor as
1749 * something that needs to be handled for hangups.
1754 * Perform some housekeeping before deciding whether to return.
1756 * If _either_ side is closing, make sure there aren't any
1757 * processes that still think tty or o_tty is their controlling
1761 read_lock(&tasklist_lock
);
1762 session_clear_tty(tty
->session
);
1764 session_clear_tty(o_tty
->session
);
1765 read_unlock(&tasklist_lock
);
1768 /* check whether both sides are closing ... */
1769 final
= !tty
->count
&& !(o_tty
&& o_tty
->count
);
1771 tty_unlock_slave(o_tty
);
1774 /* At this point, the tty->count == 0 should ensure a dead tty
1775 cannot be re-opened by a racing opener */
1780 tty_debug_hangup(tty
, "final close\n");
1782 tty_release_struct(tty
, idx
);
1787 * tty_open_current_tty - get locked tty of current task
1788 * @device: device number
1789 * @filp: file pointer to tty
1790 * @return: locked tty of the current task iff @device is /dev/tty
1792 * Performs a re-open of the current task's controlling tty.
1794 * We cannot return driver and index like for the other nodes because
1795 * devpts will not work then. It expects inodes to be from devpts FS.
1797 static struct tty_struct
*tty_open_current_tty(dev_t device
, struct file
*filp
)
1799 struct tty_struct
*tty
;
1802 if (device
!= MKDEV(TTYAUX_MAJOR
, 0))
1805 tty
= get_current_tty();
1807 return ERR_PTR(-ENXIO
);
1809 filp
->f_flags
|= O_NONBLOCK
; /* Don't let /dev/tty block */
1812 tty_kref_put(tty
); /* safe to drop the kref now */
1814 retval
= tty_reopen(tty
);
1817 tty
= ERR_PTR(retval
);
1823 * tty_lookup_driver - lookup a tty driver for a given device file
1824 * @device: device number
1825 * @filp: file pointer to tty
1826 * @index: index for the device in the @return driver
1827 * @return: driver for this inode (with increased refcount)
1829 * If @return is not erroneous, the caller is responsible to decrement the
1830 * refcount by tty_driver_kref_put.
1832 * Locking: tty_mutex protects get_tty_driver
1834 static struct tty_driver
*tty_lookup_driver(dev_t device
, struct file
*filp
,
1837 struct tty_driver
*driver
;
1841 case MKDEV(TTY_MAJOR
, 0): {
1842 extern struct tty_driver
*console_driver
;
1843 driver
= tty_driver_kref_get(console_driver
);
1844 *index
= fg_console
;
1848 case MKDEV(TTYAUX_MAJOR
, 1): {
1849 struct tty_driver
*console_driver
= console_device(index
);
1850 if (console_driver
) {
1851 driver
= tty_driver_kref_get(console_driver
);
1852 if (driver
&& filp
) {
1853 /* Don't let /dev/console block */
1854 filp
->f_flags
|= O_NONBLOCK
;
1858 return ERR_PTR(-ENODEV
);
1861 driver
= get_tty_driver(device
, index
);
1863 return ERR_PTR(-ENODEV
);
1870 * tty_kopen - open a tty device for kernel
1871 * @device: dev_t of device to open
1873 * Opens tty exclusively for kernel. Performs the driver lookup,
1874 * makes sure it's not already opened and performs the first-time
1875 * tty initialization.
1877 * Returns the locked initialized &tty_struct
1879 * Claims the global tty_mutex to serialize:
1880 * - concurrent first-time tty initialization
1881 * - concurrent tty driver removal w/ lookup
1882 * - concurrent tty removal from driver table
1884 struct tty_struct
*tty_kopen(dev_t device
)
1886 struct tty_struct
*tty
;
1887 struct tty_driver
*driver
= NULL
;
1890 mutex_lock(&tty_mutex
);
1891 driver
= tty_lookup_driver(device
, NULL
, &index
);
1892 if (IS_ERR(driver
)) {
1893 mutex_unlock(&tty_mutex
);
1894 return ERR_CAST(driver
);
1897 /* check whether we're reopening an existing tty */
1898 tty
= tty_driver_lookup_tty(driver
, NULL
, index
);
1903 /* drop kref from tty_driver_lookup_tty() */
1905 tty
= ERR_PTR(-EBUSY
);
1906 } else { /* tty_init_dev returns tty with the tty_lock held */
1907 tty
= tty_init_dev(driver
, index
);
1910 tty_port_set_kopened(tty
->port
, 1);
1913 mutex_unlock(&tty_mutex
);
1914 tty_driver_kref_put(driver
);
1917 EXPORT_SYMBOL_GPL(tty_kopen
);
1920 * tty_open_by_driver - open a tty device
1921 * @device: dev_t of device to open
1922 * @inode: inode of device file
1923 * @filp: file pointer to tty
1925 * Performs the driver lookup, checks for a reopen, or otherwise
1926 * performs the first-time tty initialization.
1928 * Returns the locked initialized or re-opened &tty_struct
1930 * Claims the global tty_mutex to serialize:
1931 * - concurrent first-time tty initialization
1932 * - concurrent tty driver removal w/ lookup
1933 * - concurrent tty removal from driver table
1935 static struct tty_struct
*tty_open_by_driver(dev_t device
, struct inode
*inode
,
1938 struct tty_struct
*tty
;
1939 struct tty_driver
*driver
= NULL
;
1943 mutex_lock(&tty_mutex
);
1944 driver
= tty_lookup_driver(device
, filp
, &index
);
1945 if (IS_ERR(driver
)) {
1946 mutex_unlock(&tty_mutex
);
1947 return ERR_CAST(driver
);
1950 /* check whether we're reopening an existing tty */
1951 tty
= tty_driver_lookup_tty(driver
, filp
, index
);
1953 mutex_unlock(&tty_mutex
);
1958 if (tty_port_kopened(tty
->port
)) {
1960 mutex_unlock(&tty_mutex
);
1961 tty
= ERR_PTR(-EBUSY
);
1964 mutex_unlock(&tty_mutex
);
1965 retval
= tty_lock_interruptible(tty
);
1966 tty_kref_put(tty
); /* drop kref from tty_driver_lookup_tty() */
1968 if (retval
== -EINTR
)
1969 retval
= -ERESTARTSYS
;
1970 tty
= ERR_PTR(retval
);
1973 retval
= tty_reopen(tty
);
1976 tty
= ERR_PTR(retval
);
1978 } else { /* Returns with the tty_lock held for now */
1979 tty
= tty_init_dev(driver
, index
);
1980 mutex_unlock(&tty_mutex
);
1983 tty_driver_kref_put(driver
);
1988 * tty_open - open a tty device
1989 * @inode: inode of device file
1990 * @filp: file pointer to tty
1992 * tty_open and tty_release keep up the tty count that contains the
1993 * number of opens done on a tty. We cannot use the inode-count, as
1994 * different inodes might point to the same tty.
1996 * Open-counting is needed for pty masters, as well as for keeping
1997 * track of serial lines: DTR is dropped when the last close happens.
1998 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2000 * The termios state of a pty is reset on first open so that
2001 * settings don't persist across reuse.
2003 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
2004 * tty->count should protect the rest.
2005 * ->siglock protects ->signal/->sighand
2007 * Note: the tty_unlock/lock cases without a ref are only safe due to
2011 static int tty_open(struct inode
*inode
, struct file
*filp
)
2013 struct tty_struct
*tty
;
2015 dev_t device
= inode
->i_rdev
;
2016 unsigned saved_flags
= filp
->f_flags
;
2018 nonseekable_open(inode
, filp
);
2021 retval
= tty_alloc_file(filp
);
2025 tty
= tty_open_current_tty(device
, filp
);
2027 tty
= tty_open_by_driver(device
, inode
, filp
);
2030 tty_free_file(filp
);
2031 retval
= PTR_ERR(tty
);
2032 if (retval
!= -EAGAIN
|| signal_pending(current
))
2038 tty_add_file(tty
, filp
);
2040 check_tty_count(tty
, __func__
);
2041 tty_debug_hangup(tty
, "opening (count=%d)\n", tty
->count
);
2044 retval
= tty
->ops
->open(tty
, filp
);
2047 filp
->f_flags
= saved_flags
;
2050 tty_debug_hangup(tty
, "open error %d, releasing\n", retval
);
2052 tty_unlock(tty
); /* need to call tty_release without BTM */
2053 tty_release(inode
, filp
);
2054 if (retval
!= -ERESTARTSYS
)
2057 if (signal_pending(current
))
2062 * Need to reset f_op in case a hangup happened.
2064 if (tty_hung_up_p(filp
))
2065 filp
->f_op
= &tty_fops
;
2068 clear_bit(TTY_HUPPED
, &tty
->flags
);
2070 noctty
= (filp
->f_flags
& O_NOCTTY
) ||
2071 (IS_ENABLED(CONFIG_VT
) && device
== MKDEV(TTY_MAJOR
, 0)) ||
2072 device
== MKDEV(TTYAUX_MAJOR
, 1) ||
2073 (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2074 tty
->driver
->subtype
== PTY_TYPE_MASTER
);
2076 tty_open_proc_set_tty(filp
, tty
);
2084 * tty_poll - check tty status
2085 * @filp: file being polled
2086 * @wait: poll wait structures to update
2088 * Call the line discipline polling method to obtain the poll
2089 * status of the device.
2091 * Locking: locks called line discipline but ldisc poll method
2092 * may be re-entered freely by other callers.
2095 static unsigned int tty_poll(struct file
*filp
, poll_table
*wait
)
2097 struct tty_struct
*tty
= file_tty(filp
);
2098 struct tty_ldisc
*ld
;
2101 if (tty_paranoia_check(tty
, file_inode(filp
), "tty_poll"))
2104 ld
= tty_ldisc_ref_wait(tty
);
2106 return hung_up_tty_poll(filp
, wait
);
2108 ret
= ld
->ops
->poll(tty
, filp
, wait
);
2109 tty_ldisc_deref(ld
);
2113 static int __tty_fasync(int fd
, struct file
*filp
, int on
)
2115 struct tty_struct
*tty
= file_tty(filp
);
2116 unsigned long flags
;
2119 if (tty_paranoia_check(tty
, file_inode(filp
), "tty_fasync"))
2122 retval
= fasync_helper(fd
, filp
, on
, &tty
->fasync
);
2130 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2133 type
= PIDTYPE_PGID
;
2135 pid
= task_pid(current
);
2139 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2140 __f_setown(filp
, pid
, type
, 0);
2148 static int tty_fasync(int fd
, struct file
*filp
, int on
)
2150 struct tty_struct
*tty
= file_tty(filp
);
2151 int retval
= -ENOTTY
;
2154 if (!tty_hung_up_p(filp
))
2155 retval
= __tty_fasync(fd
, filp
, on
);
2162 * tiocsti - fake input character
2163 * @tty: tty to fake input into
2164 * @p: pointer to character
2166 * Fake input to a tty device. Does the necessary locking and
2169 * FIXME: does not honour flow control ??
2172 * Called functions take tty_ldiscs_lock
2173 * current->signal->tty check is safe without locks
2175 * FIXME: may race normal receive processing
2178 static int tiocsti(struct tty_struct
*tty
, char __user
*p
)
2181 struct tty_ldisc
*ld
;
2183 if ((current
->signal
->tty
!= tty
) && !capable(CAP_SYS_ADMIN
))
2185 if (get_user(ch
, p
))
2187 tty_audit_tiocsti(tty
, ch
);
2188 ld
= tty_ldisc_ref_wait(tty
);
2191 ld
->ops
->receive_buf(tty
, &ch
, &mbz
, 1);
2192 tty_ldisc_deref(ld
);
2197 * tiocgwinsz - implement window query ioctl
2199 * @arg: user buffer for result
2201 * Copies the kernel idea of the window size into the user buffer.
2203 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2207 static int tiocgwinsz(struct tty_struct
*tty
, struct winsize __user
*arg
)
2211 mutex_lock(&tty
->winsize_mutex
);
2212 err
= copy_to_user(arg
, &tty
->winsize
, sizeof(*arg
));
2213 mutex_unlock(&tty
->winsize_mutex
);
2215 return err
? -EFAULT
: 0;
2219 * tty_do_resize - resize event
2220 * @tty: tty being resized
2221 * @rows: rows (character)
2222 * @cols: cols (character)
2224 * Update the termios variables and send the necessary signals to
2225 * peform a terminal resize correctly
2228 int tty_do_resize(struct tty_struct
*tty
, struct winsize
*ws
)
2233 mutex_lock(&tty
->winsize_mutex
);
2234 if (!memcmp(ws
, &tty
->winsize
, sizeof(*ws
)))
2237 /* Signal the foreground process group */
2238 pgrp
= tty_get_pgrp(tty
);
2240 kill_pgrp(pgrp
, SIGWINCH
, 1);
2245 mutex_unlock(&tty
->winsize_mutex
);
2248 EXPORT_SYMBOL(tty_do_resize
);
2251 * tiocswinsz - implement window size set ioctl
2252 * @tty; tty side of tty
2253 * @arg: user buffer for result
2255 * Copies the user idea of the window size to the kernel. Traditionally
2256 * this is just advisory information but for the Linux console it
2257 * actually has driver level meaning and triggers a VC resize.
2260 * Driver dependent. The default do_resize method takes the
2261 * tty termios mutex and ctrl_lock. The console takes its own lock
2262 * then calls into the default method.
2265 static int tiocswinsz(struct tty_struct
*tty
, struct winsize __user
*arg
)
2267 struct winsize tmp_ws
;
2268 if (copy_from_user(&tmp_ws
, arg
, sizeof(*arg
)))
2271 if (tty
->ops
->resize
)
2272 return tty
->ops
->resize(tty
, &tmp_ws
);
2274 return tty_do_resize(tty
, &tmp_ws
);
2278 * tioccons - allow admin to move logical console
2279 * @file: the file to become console
2281 * Allow the administrator to move the redirected console device
2283 * Locking: uses redirect_lock to guard the redirect information
2286 static int tioccons(struct file
*file
)
2288 if (!capable(CAP_SYS_ADMIN
))
2290 if (file
->f_op
->write
== redirected_tty_write
) {
2292 spin_lock(&redirect_lock
);
2295 spin_unlock(&redirect_lock
);
2300 spin_lock(&redirect_lock
);
2302 spin_unlock(&redirect_lock
);
2305 redirect
= get_file(file
);
2306 spin_unlock(&redirect_lock
);
2311 * fionbio - non blocking ioctl
2312 * @file: file to set blocking value
2313 * @p: user parameter
2315 * Historical tty interfaces had a blocking control ioctl before
2316 * the generic functionality existed. This piece of history is preserved
2317 * in the expected tty API of posix OS's.
2319 * Locking: none, the open file handle ensures it won't go away.
2322 static int fionbio(struct file
*file
, int __user
*p
)
2326 if (get_user(nonblock
, p
))
2329 spin_lock(&file
->f_lock
);
2331 file
->f_flags
|= O_NONBLOCK
;
2333 file
->f_flags
&= ~O_NONBLOCK
;
2334 spin_unlock(&file
->f_lock
);
2339 * tiocsetd - set line discipline
2341 * @p: pointer to user data
2343 * Set the line discipline according to user request.
2345 * Locking: see tty_set_ldisc, this function is just a helper
2348 static int tiocsetd(struct tty_struct
*tty
, int __user
*p
)
2353 if (get_user(disc
, p
))
2356 ret
= tty_set_ldisc(tty
, disc
);
2362 * tiocgetd - get line discipline
2364 * @p: pointer to user data
2366 * Retrieves the line discipline id directly from the ldisc.
2368 * Locking: waits for ldisc reference (in case the line discipline
2369 * is changing or the tty is being hungup)
2372 static int tiocgetd(struct tty_struct
*tty
, int __user
*p
)
2374 struct tty_ldisc
*ld
;
2377 ld
= tty_ldisc_ref_wait(tty
);
2380 ret
= put_user(ld
->ops
->num
, p
);
2381 tty_ldisc_deref(ld
);
2386 * send_break - performed time break
2387 * @tty: device to break on
2388 * @duration: timeout in mS
2390 * Perform a timed break on hardware that lacks its own driver level
2391 * timed break functionality.
2394 * atomic_write_lock serializes
2398 static int send_break(struct tty_struct
*tty
, unsigned int duration
)
2402 if (tty
->ops
->break_ctl
== NULL
)
2405 if (tty
->driver
->flags
& TTY_DRIVER_HARDWARE_BREAK
)
2406 retval
= tty
->ops
->break_ctl(tty
, duration
);
2408 /* Do the work ourselves */
2409 if (tty_write_lock(tty
, 0) < 0)
2411 retval
= tty
->ops
->break_ctl(tty
, -1);
2414 if (!signal_pending(current
))
2415 msleep_interruptible(duration
);
2416 retval
= tty
->ops
->break_ctl(tty
, 0);
2418 tty_write_unlock(tty
);
2419 if (signal_pending(current
))
2426 * tty_tiocmget - get modem status
2428 * @file: user file pointer
2429 * @p: pointer to result
2431 * Obtain the modem status bits from the tty driver if the feature
2432 * is supported. Return -EINVAL if it is not available.
2434 * Locking: none (up to the driver)
2437 static int tty_tiocmget(struct tty_struct
*tty
, int __user
*p
)
2439 int retval
= -EINVAL
;
2441 if (tty
->ops
->tiocmget
) {
2442 retval
= tty
->ops
->tiocmget(tty
);
2445 retval
= put_user(retval
, p
);
2451 * tty_tiocmset - set modem status
2453 * @cmd: command - clear bits, set bits or set all
2454 * @p: pointer to desired bits
2456 * Set the modem status bits from the tty driver if the feature
2457 * is supported. Return -EINVAL if it is not available.
2459 * Locking: none (up to the driver)
2462 static int tty_tiocmset(struct tty_struct
*tty
, unsigned int cmd
,
2466 unsigned int set
, clear
, val
;
2468 if (tty
->ops
->tiocmset
== NULL
)
2471 retval
= get_user(val
, p
);
2487 set
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
2488 clear
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
2489 return tty
->ops
->tiocmset(tty
, set
, clear
);
2492 static int tty_tiocgicount(struct tty_struct
*tty
, void __user
*arg
)
2494 int retval
= -EINVAL
;
2495 struct serial_icounter_struct icount
;
2496 memset(&icount
, 0, sizeof(icount
));
2497 if (tty
->ops
->get_icount
)
2498 retval
= tty
->ops
->get_icount(tty
, &icount
);
2501 if (copy_to_user(arg
, &icount
, sizeof(icount
)))
2506 static void tty_warn_deprecated_flags(struct serial_struct __user
*ss
)
2508 static DEFINE_RATELIMIT_STATE(depr_flags
,
2509 DEFAULT_RATELIMIT_INTERVAL
,
2510 DEFAULT_RATELIMIT_BURST
);
2511 char comm
[TASK_COMM_LEN
];
2514 if (get_user(flags
, &ss
->flags
))
2517 flags
&= ASYNC_DEPRECATED
;
2519 if (flags
&& __ratelimit(&depr_flags
))
2520 pr_warn("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2521 __func__
, get_task_comm(comm
, current
), flags
);
2525 * if pty, return the slave side (real_tty)
2526 * otherwise, return self
2528 static struct tty_struct
*tty_pair_get_tty(struct tty_struct
*tty
)
2530 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2531 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
2537 * Split this up, as gcc can choke on it otherwise..
2539 long tty_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
2541 struct tty_struct
*tty
= file_tty(file
);
2542 struct tty_struct
*real_tty
;
2543 void __user
*p
= (void __user
*)arg
;
2545 struct tty_ldisc
*ld
;
2547 if (tty_paranoia_check(tty
, file_inode(file
), "tty_ioctl"))
2550 real_tty
= tty_pair_get_tty(tty
);
2553 * Factor out some common prep work
2561 retval
= tty_check_change(tty
);
2564 if (cmd
!= TIOCCBRK
) {
2565 tty_wait_until_sent(tty
, 0);
2566 if (signal_pending(current
))
2577 return tiocsti(tty
, p
);
2579 return tiocgwinsz(real_tty
, p
);
2581 return tiocswinsz(real_tty
, p
);
2583 return real_tty
!= tty
? -EINVAL
: tioccons(file
);
2585 return fionbio(file
, p
);
2587 set_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2590 clear_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2594 int excl
= test_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2595 return put_user(excl
, (int __user
*)p
);
2598 return tiocgetd(tty
, p
);
2600 return tiocsetd(tty
, p
);
2602 if (!capable(CAP_SYS_ADMIN
))
2608 unsigned int ret
= new_encode_dev(tty_devnum(real_tty
));
2609 return put_user(ret
, (unsigned int __user
*)p
);
2614 case TIOCSBRK
: /* Turn break on, unconditionally */
2615 if (tty
->ops
->break_ctl
)
2616 return tty
->ops
->break_ctl(tty
, -1);
2618 case TIOCCBRK
: /* Turn break off, unconditionally */
2619 if (tty
->ops
->break_ctl
)
2620 return tty
->ops
->break_ctl(tty
, 0);
2622 case TCSBRK
: /* SVID version: non-zero arg --> no break */
2623 /* non-zero arg means wait for all output data
2624 * to be sent (performed above) but don't send break.
2625 * This is used by the tcdrain() termios function.
2628 return send_break(tty
, 250);
2630 case TCSBRKP
: /* support for POSIX tcsendbreak() */
2631 return send_break(tty
, arg
? arg
*100 : 250);
2634 return tty_tiocmget(tty
, p
);
2638 return tty_tiocmset(tty
, cmd
, p
);
2640 retval
= tty_tiocgicount(tty
, p
);
2641 /* For the moment allow fall through to the old method */
2642 if (retval
!= -EINVAL
)
2649 /* flush tty buffer and allow ldisc to process ioctl */
2650 tty_buffer_flush(tty
, NULL
);
2655 tty_warn_deprecated_flags(p
);
2658 /* Special because the struct file is needed */
2659 return ptm_open_peer(file
, tty
, (int)arg
);
2661 retval
= tty_jobctrl_ioctl(tty
, real_tty
, file
, cmd
, arg
);
2662 if (retval
!= -ENOIOCTLCMD
)
2665 if (tty
->ops
->ioctl
) {
2666 retval
= tty
->ops
->ioctl(tty
, cmd
, arg
);
2667 if (retval
!= -ENOIOCTLCMD
)
2670 ld
= tty_ldisc_ref_wait(tty
);
2672 return hung_up_tty_ioctl(file
, cmd
, arg
);
2674 if (ld
->ops
->ioctl
) {
2675 retval
= ld
->ops
->ioctl(tty
, file
, cmd
, arg
);
2676 if (retval
== -ENOIOCTLCMD
)
2679 tty_ldisc_deref(ld
);
2683 #ifdef CONFIG_COMPAT
2684 static long tty_compat_ioctl(struct file
*file
, unsigned int cmd
,
2687 struct tty_struct
*tty
= file_tty(file
);
2688 struct tty_ldisc
*ld
;
2689 int retval
= -ENOIOCTLCMD
;
2691 if (tty_paranoia_check(tty
, file_inode(file
), "tty_ioctl"))
2694 if (tty
->ops
->compat_ioctl
) {
2695 retval
= tty
->ops
->compat_ioctl(tty
, cmd
, arg
);
2696 if (retval
!= -ENOIOCTLCMD
)
2700 ld
= tty_ldisc_ref_wait(tty
);
2702 return hung_up_tty_compat_ioctl(file
, cmd
, arg
);
2703 if (ld
->ops
->compat_ioctl
)
2704 retval
= ld
->ops
->compat_ioctl(tty
, file
, cmd
, arg
);
2706 retval
= n_tty_compat_ioctl_helper(tty
, file
, cmd
, arg
);
2707 tty_ldisc_deref(ld
);
2713 static int this_tty(const void *t
, struct file
*file
, unsigned fd
)
2715 if (likely(file
->f_op
->read
!= tty_read
))
2717 return file_tty(file
) != t
? 0 : fd
+ 1;
2721 * This implements the "Secure Attention Key" --- the idea is to
2722 * prevent trojan horses by killing all processes associated with this
2723 * tty when the user hits the "Secure Attention Key". Required for
2724 * super-paranoid applications --- see the Orange Book for more details.
2726 * This code could be nicer; ideally it should send a HUP, wait a few
2727 * seconds, then send a INT, and then a KILL signal. But you then
2728 * have to coordinate with the init process, since all processes associated
2729 * with the current tty must be dead before the new getty is allowed
2732 * Now, if it would be correct ;-/ The current code has a nasty hole -
2733 * it doesn't catch files in flight. We may send the descriptor to ourselves
2734 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2736 * Nasty bug: do_SAK is being called in interrupt context. This can
2737 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2739 void __do_SAK(struct tty_struct
*tty
)
2744 struct task_struct
*g
, *p
;
2745 struct pid
*session
;
2750 session
= tty
->session
;
2752 tty_ldisc_flush(tty
);
2754 tty_driver_flush_buffer(tty
);
2756 read_lock(&tasklist_lock
);
2757 /* Kill the entire session */
2758 do_each_pid_task(session
, PIDTYPE_SID
, p
) {
2759 tty_notice(tty
, "SAK: killed process %d (%s): by session\n",
2760 task_pid_nr(p
), p
->comm
);
2761 send_sig(SIGKILL
, p
, 1);
2762 } while_each_pid_task(session
, PIDTYPE_SID
, p
);
2764 /* Now kill any processes that happen to have the tty open */
2765 do_each_thread(g
, p
) {
2766 if (p
->signal
->tty
== tty
) {
2767 tty_notice(tty
, "SAK: killed process %d (%s): by controlling tty\n",
2768 task_pid_nr(p
), p
->comm
);
2769 send_sig(SIGKILL
, p
, 1);
2773 i
= iterate_fd(p
->files
, 0, this_tty
, tty
);
2775 tty_notice(tty
, "SAK: killed process %d (%s): by fd#%d\n",
2776 task_pid_nr(p
), p
->comm
, i
- 1);
2777 force_sig(SIGKILL
, p
);
2780 } while_each_thread(g
, p
);
2781 read_unlock(&tasklist_lock
);
2785 static void do_SAK_work(struct work_struct
*work
)
2787 struct tty_struct
*tty
=
2788 container_of(work
, struct tty_struct
, SAK_work
);
2793 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2794 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2795 * the values which we write to it will be identical to the values which it
2796 * already has. --akpm
2798 void do_SAK(struct tty_struct
*tty
)
2802 schedule_work(&tty
->SAK_work
);
2805 EXPORT_SYMBOL(do_SAK
);
2807 static int dev_match_devt(struct device
*dev
, const void *data
)
2809 const dev_t
*devt
= data
;
2810 return dev
->devt
== *devt
;
2813 /* Must put_device() after it's unused! */
2814 static struct device
*tty_get_device(struct tty_struct
*tty
)
2816 dev_t devt
= tty_devnum(tty
);
2817 return class_find_device(tty_class
, NULL
, &devt
, dev_match_devt
);
2824 * This subroutine allocates and initializes a tty structure.
2826 * Locking: none - tty in question is not exposed at this point
2829 struct tty_struct
*alloc_tty_struct(struct tty_driver
*driver
, int idx
)
2831 struct tty_struct
*tty
;
2833 tty
= kzalloc(sizeof(*tty
), GFP_KERNEL
);
2837 kref_init(&tty
->kref
);
2838 tty
->magic
= TTY_MAGIC
;
2839 if (tty_ldisc_init(tty
)) {
2843 tty
->session
= NULL
;
2845 mutex_init(&tty
->legacy_mutex
);
2846 mutex_init(&tty
->throttle_mutex
);
2847 init_rwsem(&tty
->termios_rwsem
);
2848 mutex_init(&tty
->winsize_mutex
);
2849 init_ldsem(&tty
->ldisc_sem
);
2850 init_waitqueue_head(&tty
->write_wait
);
2851 init_waitqueue_head(&tty
->read_wait
);
2852 INIT_WORK(&tty
->hangup_work
, do_tty_hangup
);
2853 mutex_init(&tty
->atomic_write_lock
);
2854 spin_lock_init(&tty
->ctrl_lock
);
2855 spin_lock_init(&tty
->flow_lock
);
2856 spin_lock_init(&tty
->files_lock
);
2857 INIT_LIST_HEAD(&tty
->tty_files
);
2858 INIT_WORK(&tty
->SAK_work
, do_SAK_work
);
2860 tty
->driver
= driver
;
2861 tty
->ops
= driver
->ops
;
2863 tty_line_name(driver
, idx
, tty
->name
);
2864 tty
->dev
= tty_get_device(tty
);
2870 * tty_put_char - write one character to a tty
2874 * Write one byte to the tty using the provided put_char method
2875 * if present. Returns the number of characters successfully output.
2877 * Note: the specific put_char operation in the driver layer may go
2878 * away soon. Don't call it directly, use this method
2881 int tty_put_char(struct tty_struct
*tty
, unsigned char ch
)
2883 if (tty
->ops
->put_char
)
2884 return tty
->ops
->put_char(tty
, ch
);
2885 return tty
->ops
->write(tty
, &ch
, 1);
2887 EXPORT_SYMBOL_GPL(tty_put_char
);
2889 struct class *tty_class
;
2891 static int tty_cdev_add(struct tty_driver
*driver
, dev_t dev
,
2892 unsigned int index
, unsigned int count
)
2896 /* init here, since reused cdevs cause crashes */
2897 driver
->cdevs
[index
] = cdev_alloc();
2898 if (!driver
->cdevs
[index
])
2900 driver
->cdevs
[index
]->ops
= &tty_fops
;
2901 driver
->cdevs
[index
]->owner
= driver
->owner
;
2902 err
= cdev_add(driver
->cdevs
[index
], dev
, count
);
2904 kobject_put(&driver
->cdevs
[index
]->kobj
);
2909 * tty_register_device - register a tty device
2910 * @driver: the tty driver that describes the tty device
2911 * @index: the index in the tty driver for this tty device
2912 * @device: a struct device that is associated with this tty device.
2913 * This field is optional, if there is no known struct device
2914 * for this tty device it can be set to NULL safely.
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
2927 struct device
*tty_register_device(struct tty_driver
*driver
, unsigned index
,
2928 struct device
*device
)
2930 return tty_register_device_attr(driver
, index
, device
, NULL
, NULL
);
2932 EXPORT_SYMBOL(tty_register_device
);
2934 static void tty_device_create_release(struct device
*dev
)
2936 dev_dbg(dev
, "releasing...\n");
2941 * tty_register_device_attr - register a tty device
2942 * @driver: the tty driver that describes the tty device
2943 * @index: the index in the tty driver for this tty device
2944 * @device: a struct device that is associated with this tty device.
2945 * This field is optional, if there is no known struct device
2946 * for this tty device it can be set to NULL safely.
2947 * @drvdata: Driver data to be set to device.
2948 * @attr_grp: Attribute group to be set on device.
2950 * Returns a pointer to the struct device for this tty device
2951 * (or ERR_PTR(-EFOO) on error).
2953 * This call is required to be made to register an individual tty device
2954 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2955 * that bit is not set, this function should not be called by a tty
2960 struct device
*tty_register_device_attr(struct tty_driver
*driver
,
2961 unsigned index
, struct device
*device
,
2963 const struct attribute_group
**attr_grp
)
2966 dev_t devt
= MKDEV(driver
->major
, driver
->minor_start
) + index
;
2967 struct ktermios
*tp
;
2971 if (index
>= driver
->num
) {
2972 pr_err("%s: Attempt to register invalid tty line number (%d)\n",
2973 driver
->name
, index
);
2974 return ERR_PTR(-EINVAL
);
2977 if (driver
->type
== TTY_DRIVER_TYPE_PTY
)
2978 pty_line_name(driver
, index
, name
);
2980 tty_line_name(driver
, index
, name
);
2982 dev
= kzalloc(sizeof(*dev
), GFP_KERNEL
);
2984 return ERR_PTR(-ENOMEM
);
2987 dev
->class = tty_class
;
2988 dev
->parent
= device
;
2989 dev
->release
= tty_device_create_release
;
2990 dev_set_name(dev
, "%s", name
);
2991 dev
->groups
= attr_grp
;
2992 dev_set_drvdata(dev
, drvdata
);
2994 dev_set_uevent_suppress(dev
, 1);
2996 retval
= device_register(dev
);
3000 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
)) {
3002 * Free any saved termios data so that the termios state is
3003 * reset when reusing a minor number.
3005 tp
= driver
->termios
[index
];
3007 driver
->termios
[index
] = NULL
;
3011 retval
= tty_cdev_add(driver
, devt
, index
, 1);
3016 dev_set_uevent_suppress(dev
, 0);
3017 kobject_uevent(&dev
->kobj
, KOBJ_ADD
);
3026 return ERR_PTR(retval
);
3028 EXPORT_SYMBOL_GPL(tty_register_device_attr
);
3031 * tty_unregister_device - unregister a tty device
3032 * @driver: the tty driver that describes the tty device
3033 * @index: the index in the tty driver for this tty device
3035 * If a tty device is registered with a call to tty_register_device() then
3036 * this function must be called when the tty device is gone.
3041 void tty_unregister_device(struct tty_driver
*driver
, unsigned index
)
3043 device_destroy(tty_class
,
3044 MKDEV(driver
->major
, driver
->minor_start
) + index
);
3045 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
)) {
3046 cdev_del(driver
->cdevs
[index
]);
3047 driver
->cdevs
[index
] = NULL
;
3050 EXPORT_SYMBOL(tty_unregister_device
);
3053 * __tty_alloc_driver -- allocate tty driver
3054 * @lines: count of lines this driver can handle at most
3055 * @owner: module which is responsible for this driver
3056 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3058 * This should not be called directly, some of the provided macros should be
3059 * used instead. Use IS_ERR and friends on @retval.
3061 struct tty_driver
*__tty_alloc_driver(unsigned int lines
, struct module
*owner
,
3062 unsigned long flags
)
3064 struct tty_driver
*driver
;
3065 unsigned int cdevs
= 1;
3068 if (!lines
|| (flags
& TTY_DRIVER_UNNUMBERED_NODE
&& lines
> 1))
3069 return ERR_PTR(-EINVAL
);
3071 driver
= kzalloc(sizeof(struct tty_driver
), GFP_KERNEL
);
3073 return ERR_PTR(-ENOMEM
);
3075 kref_init(&driver
->kref
);
3076 driver
->magic
= TTY_DRIVER_MAGIC
;
3077 driver
->num
= lines
;
3078 driver
->owner
= owner
;
3079 driver
->flags
= flags
;
3081 if (!(flags
& TTY_DRIVER_DEVPTS_MEM
)) {
3082 driver
->ttys
= kcalloc(lines
, sizeof(*driver
->ttys
),
3084 driver
->termios
= kcalloc(lines
, sizeof(*driver
->termios
),
3086 if (!driver
->ttys
|| !driver
->termios
) {
3092 if (!(flags
& TTY_DRIVER_DYNAMIC_ALLOC
)) {
3093 driver
->ports
= kcalloc(lines
, sizeof(*driver
->ports
),
3095 if (!driver
->ports
) {
3102 driver
->cdevs
= kcalloc(cdevs
, sizeof(*driver
->cdevs
), GFP_KERNEL
);
3103 if (!driver
->cdevs
) {
3110 kfree(driver
->ports
);
3111 kfree(driver
->ttys
);
3112 kfree(driver
->termios
);
3113 kfree(driver
->cdevs
);
3115 return ERR_PTR(err
);
3117 EXPORT_SYMBOL(__tty_alloc_driver
);
3119 static void destruct_tty_driver(struct kref
*kref
)
3121 struct tty_driver
*driver
= container_of(kref
, struct tty_driver
, kref
);
3123 struct ktermios
*tp
;
3125 if (driver
->flags
& TTY_DRIVER_INSTALLED
) {
3126 for (i
= 0; i
< driver
->num
; i
++) {
3127 tp
= driver
->termios
[i
];
3129 driver
->termios
[i
] = NULL
;
3132 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
))
3133 tty_unregister_device(driver
, i
);
3135 proc_tty_unregister_driver(driver
);
3136 if (driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
)
3137 cdev_del(driver
->cdevs
[0]);
3139 kfree(driver
->cdevs
);
3140 kfree(driver
->ports
);
3141 kfree(driver
->termios
);
3142 kfree(driver
->ttys
);
3146 void tty_driver_kref_put(struct tty_driver
*driver
)
3148 kref_put(&driver
->kref
, destruct_tty_driver
);
3150 EXPORT_SYMBOL(tty_driver_kref_put
);
3152 void tty_set_operations(struct tty_driver
*driver
,
3153 const struct tty_operations
*op
)
3157 EXPORT_SYMBOL(tty_set_operations
);
3159 void put_tty_driver(struct tty_driver
*d
)
3161 tty_driver_kref_put(d
);
3163 EXPORT_SYMBOL(put_tty_driver
);
3166 * Called by a tty driver to register itself.
3168 int tty_register_driver(struct tty_driver
*driver
)
3175 if (!driver
->major
) {
3176 error
= alloc_chrdev_region(&dev
, driver
->minor_start
,
3177 driver
->num
, driver
->name
);
3179 driver
->major
= MAJOR(dev
);
3180 driver
->minor_start
= MINOR(dev
);
3183 dev
= MKDEV(driver
->major
, driver
->minor_start
);
3184 error
= register_chrdev_region(dev
, driver
->num
, driver
->name
);
3189 if (driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
) {
3190 error
= tty_cdev_add(driver
, dev
, 0, driver
->num
);
3192 goto err_unreg_char
;
3195 mutex_lock(&tty_mutex
);
3196 list_add(&driver
->tty_drivers
, &tty_drivers
);
3197 mutex_unlock(&tty_mutex
);
3199 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
)) {
3200 for (i
= 0; i
< driver
->num
; i
++) {
3201 d
= tty_register_device(driver
, i
, NULL
);
3204 goto err_unreg_devs
;
3208 proc_tty_register_driver(driver
);
3209 driver
->flags
|= TTY_DRIVER_INSTALLED
;
3213 for (i
--; i
>= 0; i
--)
3214 tty_unregister_device(driver
, i
);
3216 mutex_lock(&tty_mutex
);
3217 list_del(&driver
->tty_drivers
);
3218 mutex_unlock(&tty_mutex
);
3221 unregister_chrdev_region(dev
, driver
->num
);
3225 EXPORT_SYMBOL(tty_register_driver
);
3228 * Called by a tty driver to unregister itself.
3230 int tty_unregister_driver(struct tty_driver
*driver
)
3234 if (driver
->refcount
)
3237 unregister_chrdev_region(MKDEV(driver
->major
, driver
->minor_start
),
3239 mutex_lock(&tty_mutex
);
3240 list_del(&driver
->tty_drivers
);
3241 mutex_unlock(&tty_mutex
);
3245 EXPORT_SYMBOL(tty_unregister_driver
);
3247 dev_t
tty_devnum(struct tty_struct
*tty
)
3249 return MKDEV(tty
->driver
->major
, tty
->driver
->minor_start
) + tty
->index
;
3251 EXPORT_SYMBOL(tty_devnum
);
3253 void tty_default_fops(struct file_operations
*fops
)
3258 static char *tty_devnode(struct device
*dev
, umode_t
*mode
)
3262 if (dev
->devt
== MKDEV(TTYAUX_MAJOR
, 0) ||
3263 dev
->devt
== MKDEV(TTYAUX_MAJOR
, 2))
3268 static int __init
tty_class_init(void)
3270 tty_class
= class_create(THIS_MODULE
, "tty");
3271 if (IS_ERR(tty_class
))
3272 return PTR_ERR(tty_class
);
3273 tty_class
->devnode
= tty_devnode
;
3277 postcore_initcall(tty_class_init
);
3279 /* 3/2004 jmc: why do these devices exist? */
3280 static struct cdev tty_cdev
, console_cdev
;
3282 static ssize_t
show_cons_active(struct device
*dev
,
3283 struct device_attribute
*attr
, char *buf
)
3285 struct console
*cs
[16];
3291 for_each_console(c
) {
3296 if ((c
->flags
& CON_ENABLED
) == 0)
3299 if (i
>= ARRAY_SIZE(cs
))
3303 int index
= cs
[i
]->index
;
3304 struct tty_driver
*drv
= cs
[i
]->device(cs
[i
], &index
);
3306 /* don't resolve tty0 as some programs depend on it */
3307 if (drv
&& (cs
[i
]->index
> 0 || drv
->major
!= TTY_MAJOR
))
3308 count
+= tty_line_name(drv
, index
, buf
+ count
);
3310 count
+= sprintf(buf
+ count
, "%s%d",
3311 cs
[i
]->name
, cs
[i
]->index
);
3313 count
+= sprintf(buf
+ count
, "%c", i
? ' ':'\n');
3319 static DEVICE_ATTR(active
, S_IRUGO
, show_cons_active
, NULL
);
3321 static struct attribute
*cons_dev_attrs
[] = {
3322 &dev_attr_active
.attr
,
3326 ATTRIBUTE_GROUPS(cons_dev
);
3328 static struct device
*consdev
;
3330 void console_sysfs_notify(void)
3333 sysfs_notify(&consdev
->kobj
, NULL
, "active");
3337 * Ok, now we can initialize the rest of the tty devices and can count
3338 * on memory allocations, interrupts etc..
3340 int __init
tty_init(void)
3342 cdev_init(&tty_cdev
, &tty_fops
);
3343 if (cdev_add(&tty_cdev
, MKDEV(TTYAUX_MAJOR
, 0), 1) ||
3344 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 0), 1, "/dev/tty") < 0)
3345 panic("Couldn't register /dev/tty driver\n");
3346 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 0), NULL
, "tty");
3348 cdev_init(&console_cdev
, &console_fops
);
3349 if (cdev_add(&console_cdev
, MKDEV(TTYAUX_MAJOR
, 1), 1) ||
3350 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 1), 1, "/dev/console") < 0)
3351 panic("Couldn't register /dev/console driver\n");
3352 consdev
= device_create_with_groups(tty_class
, NULL
,
3353 MKDEV(TTYAUX_MAJOR
, 1), NULL
,
3354 cons_dev_groups
, "console");
3355 if (IS_ERR(consdev
))
3359 vty_init(&console_fops
);