2 * Copyright (C) 1991, 1992 Linus Torvalds
6 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
7 * or rs-channels. It also implements echoing, cooked mode etc.
9 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
11 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
12 * tty_struct and tty_queue structures. Previously there was an array
13 * of 256 tty_struct's which was statically allocated, and the
14 * tty_queue structures were allocated at boot time. Both are now
15 * dynamically allocated only when the tty is open.
17 * Also restructured routines so that there is more of a separation
18 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
19 * the low-level tty routines (serial.c, pty.c, console.c). This
20 * makes for cleaner and more compact code. -TYT, 9/17/92
22 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
23 * which can be dynamically activated and de-activated by the line
24 * discipline handling modules (like SLIP).
26 * NOTE: pay no attention to the line discipline code (yet); its
27 * interface is still subject to change in this version...
30 * Added functionality to the OPOST tty handling. No delays, but all
31 * other bits should be there.
32 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
34 * Rewrote canonical mode and added more termios flags.
35 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
37 * Reorganized FASYNC support so mouse code can share it.
38 * -- ctm@ardi.com, 9Sep95
40 * New TIOCLINUX variants added.
41 * -- mj@k332.feld.cvut.cz, 19-Nov-95
43 * Restrict vt switching via ioctl()
44 * -- grif@cs.ucr.edu, 5-Dec-95
46 * Move console and virtual terminal code to more appropriate files,
47 * implement CONFIG_VT and generalize console device interface.
48 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
50 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
51 * -- Bill Hawes <whawes@star.net>, June 97
53 * Added devfs support.
54 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
56 * Added support for a Unix98-style ptmx device.
57 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
59 * Reduced memory usage for older ARM systems
60 * -- Russell King <rmk@arm.linux.org.uk>
62 * Move do_SAK() into process context. Less stack use in devfs functions.
63 * alloc_tty_struct() always uses kmalloc()
64 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
67 #include <linux/types.h>
68 #include <linux/major.h>
69 #include <linux/errno.h>
70 #include <linux/signal.h>
71 #include <linux/fcntl.h>
72 #include <linux/sched.h>
73 #include <linux/interrupt.h>
74 #include <linux/tty.h>
75 #include <linux/tty_driver.h>
76 #include <linux/tty_flip.h>
77 #include <linux/devpts_fs.h>
78 #include <linux/file.h>
79 #include <linux/fdtable.h>
80 #include <linux/console.h>
81 #include <linux/timer.h>
82 #include <linux/ctype.h>
85 #include <linux/string.h>
86 #include <linux/slab.h>
87 #include <linux/poll.h>
88 #include <linux/proc_fs.h>
89 #include <linux/init.h>
90 #include <linux/module.h>
91 #include <linux/device.h>
92 #include <linux/wait.h>
93 #include <linux/bitops.h>
94 #include <linux/delay.h>
95 #include <linux/seq_file.h>
96 #include <linux/serial.h>
97 #include <linux/ratelimit.h>
99 #include <linux/uaccess.h>
101 #include <linux/kbd_kern.h>
102 #include <linux/vt_kern.h>
103 #include <linux/selection.h>
105 #include <linux/kmod.h>
106 #include <linux/nsproxy.h>
108 #undef TTY_DEBUG_HANGUP
110 #define TTY_PARANOIA_CHECK 1
111 #define CHECK_TTY_COUNT 1
113 struct ktermios tty_std_termios
= { /* for the benefit of tty drivers */
114 .c_iflag
= ICRNL
| IXON
,
115 .c_oflag
= OPOST
| ONLCR
,
116 .c_cflag
= B38400
| CS8
| CREAD
| HUPCL
,
117 .c_lflag
= ISIG
| ICANON
| ECHO
| ECHOE
| ECHOK
|
118 ECHOCTL
| ECHOKE
| IEXTEN
,
124 EXPORT_SYMBOL(tty_std_termios
);
126 /* This list gets poked at by procfs and various bits of boot up code. This
127 could do with some rationalisation such as pulling the tty proc function
130 LIST_HEAD(tty_drivers
); /* linked list of tty drivers */
132 /* Mutex to protect creating and releasing a tty. This is shared with
133 vt.c for deeply disgusting hack reasons */
134 DEFINE_MUTEX(tty_mutex
);
135 EXPORT_SYMBOL(tty_mutex
);
137 /* Spinlock to protect the tty->tty_files list */
138 DEFINE_SPINLOCK(tty_files_lock
);
140 static ssize_t
tty_read(struct file
*, char __user
*, size_t, loff_t
*);
141 static ssize_t
tty_write(struct file
*, const char __user
*, size_t, loff_t
*);
142 ssize_t
redirected_tty_write(struct file
*, const char __user
*,
144 static unsigned int tty_poll(struct file
*, poll_table
*);
145 static int tty_open(struct inode
*, struct file
*);
146 long tty_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
);
148 static long tty_compat_ioctl(struct file
*file
, unsigned int cmd
,
151 #define tty_compat_ioctl NULL
153 static int __tty_fasync(int fd
, struct file
*filp
, int on
);
154 static int tty_fasync(int fd
, struct file
*filp
, int on
);
155 static void release_tty(struct tty_struct
*tty
, int idx
);
156 static void __proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
);
157 static void proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
);
160 * alloc_tty_struct - allocate a tty object
162 * Return a new empty tty structure. The data fields have not
163 * been initialized in any way but has been zeroed
168 struct tty_struct
*alloc_tty_struct(void)
170 return kzalloc(sizeof(struct tty_struct
), GFP_KERNEL
);
174 * free_tty_struct - free a disused tty
175 * @tty: tty struct to free
177 * Free the write buffers, tty queue and tty memory itself.
179 * Locking: none. Must be called after tty is definitely unused
182 void free_tty_struct(struct tty_struct
*tty
)
187 put_device(tty
->dev
);
188 kfree(tty
->write_buf
);
189 tty
->magic
= 0xDEADDEAD;
193 static inline struct tty_struct
*file_tty(struct file
*file
)
195 return ((struct tty_file_private
*)file
->private_data
)->tty
;
198 int tty_alloc_file(struct file
*file
)
200 struct tty_file_private
*priv
;
202 priv
= kmalloc(sizeof(*priv
), GFP_KERNEL
);
206 file
->private_data
= priv
;
211 /* Associate a new file with the tty structure */
212 void tty_add_file(struct tty_struct
*tty
, struct file
*file
)
214 struct tty_file_private
*priv
= file
->private_data
;
219 spin_lock(&tty_files_lock
);
220 list_add(&priv
->list
, &tty
->tty_files
);
221 spin_unlock(&tty_files_lock
);
225 * tty_free_file - free file->private_data
227 * This shall be used only for fail path handling when tty_add_file was not
230 void tty_free_file(struct file
*file
)
232 struct tty_file_private
*priv
= file
->private_data
;
234 file
->private_data
= NULL
;
238 /* Delete file from its tty */
239 static void tty_del_file(struct file
*file
)
241 struct tty_file_private
*priv
= file
->private_data
;
243 spin_lock(&tty_files_lock
);
244 list_del(&priv
->list
);
245 spin_unlock(&tty_files_lock
);
250 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
253 * tty_name - return tty naming
254 * @tty: tty structure
255 * @buf: buffer for output
257 * Convert a tty structure into a name. The name reflects the kernel
258 * naming policy and if udev is in use may not reflect user space
263 char *tty_name(struct tty_struct
*tty
, char *buf
)
265 if (!tty
) /* Hmm. NULL pointer. That's fun. */
266 strcpy(buf
, "NULL tty");
268 strcpy(buf
, tty
->name
);
272 EXPORT_SYMBOL(tty_name
);
274 int tty_paranoia_check(struct tty_struct
*tty
, struct inode
*inode
,
277 #ifdef TTY_PARANOIA_CHECK
280 "null TTY for (%d:%d) in %s\n",
281 imajor(inode
), iminor(inode
), routine
);
284 if (tty
->magic
!= TTY_MAGIC
) {
286 "bad magic number for tty struct (%d:%d) in %s\n",
287 imajor(inode
), iminor(inode
), routine
);
294 static int check_tty_count(struct tty_struct
*tty
, const char *routine
)
296 #ifdef CHECK_TTY_COUNT
300 spin_lock(&tty_files_lock
);
301 list_for_each(p
, &tty
->tty_files
) {
304 spin_unlock(&tty_files_lock
);
305 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
306 tty
->driver
->subtype
== PTY_TYPE_SLAVE
&&
307 tty
->link
&& tty
->link
->count
)
309 if (tty
->count
!= count
) {
310 printk(KERN_WARNING
"Warning: dev (%s) tty->count(%d) "
311 "!= #fd's(%d) in %s\n",
312 tty
->name
, tty
->count
, count
, routine
);
320 * get_tty_driver - find device of a tty
321 * @dev_t: device identifier
322 * @index: returns the index of the tty
324 * This routine returns a tty driver structure, given a device number
325 * and also passes back the index number.
327 * Locking: caller must hold tty_mutex
330 static struct tty_driver
*get_tty_driver(dev_t device
, int *index
)
332 struct tty_driver
*p
;
334 list_for_each_entry(p
, &tty_drivers
, tty_drivers
) {
335 dev_t base
= MKDEV(p
->major
, p
->minor_start
);
336 if (device
< base
|| device
>= base
+ p
->num
)
338 *index
= device
- base
;
339 return tty_driver_kref_get(p
);
344 #ifdef CONFIG_CONSOLE_POLL
347 * tty_find_polling_driver - find device of a polled tty
348 * @name: name string to match
349 * @line: pointer to resulting tty line nr
351 * This routine returns a tty driver structure, given a name
352 * and the condition that the tty driver is capable of polled
355 struct tty_driver
*tty_find_polling_driver(char *name
, int *line
)
357 struct tty_driver
*p
, *res
= NULL
;
362 for (str
= name
; *str
; str
++)
363 if ((*str
>= '0' && *str
<= '9') || *str
== ',')
369 tty_line
= simple_strtoul(str
, &str
, 10);
371 mutex_lock(&tty_mutex
);
372 /* Search through the tty devices to look for a match */
373 list_for_each_entry(p
, &tty_drivers
, tty_drivers
) {
374 if (strncmp(name
, p
->name
, len
) != 0)
382 if (tty_line
>= 0 && tty_line
< p
->num
&& p
->ops
&&
383 p
->ops
->poll_init
&& !p
->ops
->poll_init(p
, tty_line
, stp
)) {
384 res
= tty_driver_kref_get(p
);
389 mutex_unlock(&tty_mutex
);
393 EXPORT_SYMBOL_GPL(tty_find_polling_driver
);
397 * tty_check_change - check for POSIX terminal changes
400 * If we try to write to, or set the state of, a terminal and we're
401 * not in the foreground, send a SIGTTOU. If the signal is blocked or
402 * ignored, go ahead and perform the operation. (POSIX 7.2)
407 int tty_check_change(struct tty_struct
*tty
)
412 if (current
->signal
->tty
!= tty
)
415 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
418 printk(KERN_WARNING
"tty_check_change: tty->pgrp == NULL!\n");
421 if (task_pgrp(current
) == tty
->pgrp
)
423 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
424 if (is_ignored(SIGTTOU
))
426 if (is_current_pgrp_orphaned()) {
430 kill_pgrp(task_pgrp(current
), SIGTTOU
, 1);
431 set_thread_flag(TIF_SIGPENDING
);
436 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
440 EXPORT_SYMBOL(tty_check_change
);
442 static ssize_t
hung_up_tty_read(struct file
*file
, char __user
*buf
,
443 size_t count
, loff_t
*ppos
)
448 static ssize_t
hung_up_tty_write(struct file
*file
, const char __user
*buf
,
449 size_t count
, loff_t
*ppos
)
454 /* No kernel lock held - none needed ;) */
455 static unsigned int hung_up_tty_poll(struct file
*filp
, poll_table
*wait
)
457 return POLLIN
| POLLOUT
| POLLERR
| POLLHUP
| POLLRDNORM
| POLLWRNORM
;
460 static long hung_up_tty_ioctl(struct file
*file
, unsigned int cmd
,
463 return cmd
== TIOCSPGRP
? -ENOTTY
: -EIO
;
466 static long hung_up_tty_compat_ioctl(struct file
*file
,
467 unsigned int cmd
, unsigned long arg
)
469 return cmd
== TIOCSPGRP
? -ENOTTY
: -EIO
;
472 static const struct file_operations tty_fops
= {
477 .unlocked_ioctl
= tty_ioctl
,
478 .compat_ioctl
= tty_compat_ioctl
,
480 .release
= tty_release
,
481 .fasync
= tty_fasync
,
484 static const struct file_operations console_fops
= {
487 .write
= redirected_tty_write
,
489 .unlocked_ioctl
= tty_ioctl
,
490 .compat_ioctl
= tty_compat_ioctl
,
492 .release
= tty_release
,
493 .fasync
= tty_fasync
,
496 static const struct file_operations hung_up_tty_fops
= {
498 .read
= hung_up_tty_read
,
499 .write
= hung_up_tty_write
,
500 .poll
= hung_up_tty_poll
,
501 .unlocked_ioctl
= hung_up_tty_ioctl
,
502 .compat_ioctl
= hung_up_tty_compat_ioctl
,
503 .release
= tty_release
,
506 static DEFINE_SPINLOCK(redirect_lock
);
507 static struct file
*redirect
;
510 * tty_wakeup - request more data
513 * Internal and external helper for wakeups of tty. This function
514 * informs the line discipline if present that the driver is ready
515 * to receive more output data.
518 void tty_wakeup(struct tty_struct
*tty
)
520 struct tty_ldisc
*ld
;
522 if (test_bit(TTY_DO_WRITE_WAKEUP
, &tty
->flags
)) {
523 ld
= tty_ldisc_ref(tty
);
525 if (ld
->ops
->write_wakeup
)
526 ld
->ops
->write_wakeup(tty
);
530 wake_up_interruptible_poll(&tty
->write_wait
, POLLOUT
);
533 EXPORT_SYMBOL_GPL(tty_wakeup
);
536 * __tty_hangup - actual handler for hangup events
539 * This can be called by the "eventd" kernel thread. That is process
540 * synchronous but doesn't hold any locks, so we need to make sure we
541 * have the appropriate locks for what we're doing.
543 * The hangup event clears any pending redirections onto the hung up
544 * device. It ensures future writes will error and it does the needed
545 * line discipline hangup and signal delivery. The tty object itself
550 * redirect lock for undoing redirection
551 * file list lock for manipulating list of ttys
552 * tty_ldisc_lock from called functions
553 * termios_mutex resetting termios data
554 * tasklist_lock to walk task list for hangup event
555 * ->siglock to protect ->signal/->sighand
557 static void __tty_hangup(struct tty_struct
*tty
)
559 struct file
*cons_filp
= NULL
;
560 struct file
*filp
, *f
= NULL
;
561 struct task_struct
*p
;
562 struct tty_file_private
*priv
;
563 int closecount
= 0, n
;
571 spin_lock(&redirect_lock
);
572 if (redirect
&& file_tty(redirect
) == tty
) {
576 spin_unlock(&redirect_lock
);
580 /* some functions below drop BTM, so we need this bit */
581 set_bit(TTY_HUPPING
, &tty
->flags
);
583 /* inuse_filps is protected by the single tty lock,
584 this really needs to change if we want to flush the
585 workqueue with the lock held */
586 check_tty_count(tty
, "tty_hangup");
588 spin_lock(&tty_files_lock
);
589 /* This breaks for file handles being sent over AF_UNIX sockets ? */
590 list_for_each_entry(priv
, &tty
->tty_files
, list
) {
592 if (filp
->f_op
->write
== redirected_tty_write
)
594 if (filp
->f_op
->write
!= tty_write
)
597 __tty_fasync(-1, filp
, 0); /* can't block */
598 filp
->f_op
= &hung_up_tty_fops
;
600 spin_unlock(&tty_files_lock
);
603 * it drops BTM and thus races with reopen
604 * we protect the race by TTY_HUPPING
606 tty_ldisc_hangup(tty
);
608 read_lock(&tasklist_lock
);
610 do_each_pid_task(tty
->session
, PIDTYPE_SID
, p
) {
611 spin_lock_irq(&p
->sighand
->siglock
);
612 if (p
->signal
->tty
== tty
) {
613 p
->signal
->tty
= NULL
;
614 /* We defer the dereferences outside fo
618 if (!p
->signal
->leader
) {
619 spin_unlock_irq(&p
->sighand
->siglock
);
622 __group_send_sig_info(SIGHUP
, SEND_SIG_PRIV
, p
);
623 __group_send_sig_info(SIGCONT
, SEND_SIG_PRIV
, p
);
624 put_pid(p
->signal
->tty_old_pgrp
); /* A noop */
625 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
627 p
->signal
->tty_old_pgrp
= get_pid(tty
->pgrp
);
628 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
629 spin_unlock_irq(&p
->sighand
->siglock
);
630 } while_each_pid_task(tty
->session
, PIDTYPE_SID
, p
);
632 read_unlock(&tasklist_lock
);
634 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
635 clear_bit(TTY_THROTTLED
, &tty
->flags
);
636 clear_bit(TTY_PUSH
, &tty
->flags
);
637 clear_bit(TTY_DO_WRITE_WAKEUP
, &tty
->flags
);
638 put_pid(tty
->session
);
642 tty
->ctrl_status
= 0;
643 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
645 /* Account for the p->signal references we killed */
650 * If one of the devices matches a console pointer, we
651 * cannot just call hangup() because that will cause
652 * tty->count and state->count to go out of sync.
653 * So we just call close() the right number of times.
657 for (n
= 0; n
< closecount
; n
++)
658 tty
->ops
->close(tty
, cons_filp
);
659 } else if (tty
->ops
->hangup
)
660 (tty
->ops
->hangup
)(tty
);
662 * We don't want to have driver/ldisc interactions beyond
663 * the ones we did here. The driver layer expects no
664 * calls after ->hangup() from the ldisc side. However we
665 * can't yet guarantee all that.
667 set_bit(TTY_HUPPED
, &tty
->flags
);
668 clear_bit(TTY_HUPPING
, &tty
->flags
);
669 tty_ldisc_enable(tty
);
677 static void do_tty_hangup(struct work_struct
*work
)
679 struct tty_struct
*tty
=
680 container_of(work
, struct tty_struct
, hangup_work
);
686 * tty_hangup - trigger a hangup event
687 * @tty: tty to hangup
689 * A carrier loss (virtual or otherwise) has occurred on this like
690 * schedule a hangup sequence to run after this event.
693 void tty_hangup(struct tty_struct
*tty
)
695 #ifdef TTY_DEBUG_HANGUP
697 printk(KERN_DEBUG
"%s hangup...\n", tty_name(tty
, buf
));
699 schedule_work(&tty
->hangup_work
);
702 EXPORT_SYMBOL(tty_hangup
);
705 * tty_vhangup - process vhangup
706 * @tty: tty to hangup
708 * The user has asked via system call for the terminal to be hung up.
709 * We do this synchronously so that when the syscall returns the process
710 * is complete. That guarantee is necessary for security reasons.
713 void tty_vhangup(struct tty_struct
*tty
)
715 #ifdef TTY_DEBUG_HANGUP
718 printk(KERN_DEBUG
"%s vhangup...\n", tty_name(tty
, buf
));
723 EXPORT_SYMBOL(tty_vhangup
);
727 * tty_vhangup_self - process vhangup for own ctty
729 * Perform a vhangup on the current controlling tty
732 void tty_vhangup_self(void)
734 struct tty_struct
*tty
;
736 tty
= get_current_tty();
744 * tty_hung_up_p - was tty hung up
745 * @filp: file pointer of tty
747 * Return true if the tty has been subject to a vhangup or a carrier
751 int tty_hung_up_p(struct file
*filp
)
753 return (filp
->f_op
== &hung_up_tty_fops
);
756 EXPORT_SYMBOL(tty_hung_up_p
);
758 static void session_clear_tty(struct pid
*session
)
760 struct task_struct
*p
;
761 do_each_pid_task(session
, PIDTYPE_SID
, p
) {
763 } while_each_pid_task(session
, PIDTYPE_SID
, p
);
767 * disassociate_ctty - disconnect controlling tty
768 * @on_exit: true if exiting so need to "hang up" the session
770 * This function is typically called only by the session leader, when
771 * it wants to disassociate itself from its controlling tty.
773 * It performs the following functions:
774 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
775 * (2) Clears the tty from being controlling the session
776 * (3) Clears the controlling tty for all processes in the
779 * The argument on_exit is set to 1 if called when a process is
780 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
783 * BTM is taken for hysterical raisins, and held when
784 * called from no_tty().
785 * tty_mutex is taken to protect tty
786 * ->siglock is taken to protect ->signal/->sighand
787 * tasklist_lock is taken to walk process list for sessions
788 * ->siglock is taken to protect ->signal/->sighand
791 void disassociate_ctty(int on_exit
)
793 struct tty_struct
*tty
;
795 if (!current
->signal
->leader
)
798 tty
= get_current_tty();
800 struct pid
*tty_pgrp
= get_pid(tty
->pgrp
);
802 if (tty
->driver
->type
!= TTY_DRIVER_TYPE_PTY
)
807 kill_pgrp(tty_pgrp
, SIGHUP
, on_exit
);
809 kill_pgrp(tty_pgrp
, SIGCONT
, on_exit
);
812 } else if (on_exit
) {
813 struct pid
*old_pgrp
;
814 spin_lock_irq(¤t
->sighand
->siglock
);
815 old_pgrp
= current
->signal
->tty_old_pgrp
;
816 current
->signal
->tty_old_pgrp
= NULL
;
817 spin_unlock_irq(¤t
->sighand
->siglock
);
819 kill_pgrp(old_pgrp
, SIGHUP
, on_exit
);
820 kill_pgrp(old_pgrp
, SIGCONT
, on_exit
);
826 spin_lock_irq(¤t
->sighand
->siglock
);
827 put_pid(current
->signal
->tty_old_pgrp
);
828 current
->signal
->tty_old_pgrp
= NULL
;
829 spin_unlock_irq(¤t
->sighand
->siglock
);
831 tty
= get_current_tty();
834 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
835 put_pid(tty
->session
);
839 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
842 #ifdef TTY_DEBUG_HANGUP
843 printk(KERN_DEBUG
"error attempted to write to tty [0x%p]"
848 /* Now clear signal->tty under the lock */
849 read_lock(&tasklist_lock
);
850 session_clear_tty(task_session(current
));
851 read_unlock(&tasklist_lock
);
856 * no_tty - Ensure the current process does not have a controlling tty
860 /* FIXME: Review locking here. The tty_lock never covered any race
861 between a new association and proc_clear_tty but possible we need
862 to protect against this anyway */
863 struct task_struct
*tsk
= current
;
864 disassociate_ctty(0);
870 * stop_tty - propagate flow control
873 * Perform flow control to the driver. For PTY/TTY pairs we
874 * must also propagate the TIOCKPKT status. May be called
875 * on an already stopped device and will not re-call the driver
878 * This functionality is used by both the line disciplines for
879 * halting incoming flow and by the driver. It may therefore be
880 * called from any context, may be under the tty atomic_write_lock
884 * Uses the tty control lock internally
887 void stop_tty(struct tty_struct
*tty
)
890 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
892 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
896 if (tty
->link
&& tty
->link
->packet
) {
897 tty
->ctrl_status
&= ~TIOCPKT_START
;
898 tty
->ctrl_status
|= TIOCPKT_STOP
;
899 wake_up_interruptible_poll(&tty
->link
->read_wait
, POLLIN
);
901 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
903 (tty
->ops
->stop
)(tty
);
906 EXPORT_SYMBOL(stop_tty
);
909 * start_tty - propagate flow control
912 * Start a tty that has been stopped if at all possible. Perform
913 * any necessary wakeups and propagate the TIOCPKT status. If this
914 * is the tty was previous stopped and is being started then the
915 * driver start method is invoked and the line discipline woken.
921 void start_tty(struct tty_struct
*tty
)
924 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
925 if (!tty
->stopped
|| tty
->flow_stopped
) {
926 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
930 if (tty
->link
&& tty
->link
->packet
) {
931 tty
->ctrl_status
&= ~TIOCPKT_STOP
;
932 tty
->ctrl_status
|= TIOCPKT_START
;
933 wake_up_interruptible_poll(&tty
->link
->read_wait
, POLLIN
);
935 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
937 (tty
->ops
->start
)(tty
);
938 /* If we have a running line discipline it may need kicking */
942 EXPORT_SYMBOL(start_tty
);
945 * tty_read - read method for tty device files
946 * @file: pointer to tty file
948 * @count: size of user buffer
951 * Perform the read system call function on this terminal device. Checks
952 * for hung up devices before calling the line discipline method.
955 * Locks the line discipline internally while needed. Multiple
956 * read calls may be outstanding in parallel.
959 static ssize_t
tty_read(struct file
*file
, char __user
*buf
, size_t count
,
963 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
964 struct tty_struct
*tty
= file_tty(file
);
965 struct tty_ldisc
*ld
;
967 if (tty_paranoia_check(tty
, inode
, "tty_read"))
969 if (!tty
|| (test_bit(TTY_IO_ERROR
, &tty
->flags
)))
972 /* We want to wait for the line discipline to sort out in this
974 ld
= tty_ldisc_ref_wait(tty
);
976 i
= (ld
->ops
->read
)(tty
, file
, buf
, count
);
981 inode
->i_atime
= current_fs_time(inode
->i_sb
);
985 void tty_write_unlock(struct tty_struct
*tty
)
986 __releases(&tty
->atomic_write_lock
)
988 mutex_unlock(&tty
->atomic_write_lock
);
989 wake_up_interruptible_poll(&tty
->write_wait
, POLLOUT
);
992 int tty_write_lock(struct tty_struct
*tty
, int ndelay
)
993 __acquires(&tty
->atomic_write_lock
)
995 if (!mutex_trylock(&tty
->atomic_write_lock
)) {
998 if (mutex_lock_interruptible(&tty
->atomic_write_lock
))
1005 * Split writes up in sane blocksizes to avoid
1006 * denial-of-service type attacks
1008 static inline ssize_t
do_tty_write(
1009 ssize_t (*write
)(struct tty_struct
*, struct file
*, const unsigned char *, size_t),
1010 struct tty_struct
*tty
,
1012 const char __user
*buf
,
1015 ssize_t ret
, written
= 0;
1018 ret
= tty_write_lock(tty
, file
->f_flags
& O_NDELAY
);
1023 * We chunk up writes into a temporary buffer. This
1024 * simplifies low-level drivers immensely, since they
1025 * don't have locking issues and user mode accesses.
1027 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1030 * The default chunk-size is 2kB, because the NTTY
1031 * layer has problems with bigger chunks. It will
1032 * claim to be able to handle more characters than
1035 * FIXME: This can probably go away now except that 64K chunks
1036 * are too likely to fail unless switched to vmalloc...
1039 if (test_bit(TTY_NO_WRITE_SPLIT
, &tty
->flags
))
1044 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1045 if (tty
->write_cnt
< chunk
) {
1046 unsigned char *buf_chunk
;
1051 buf_chunk
= kmalloc(chunk
, GFP_KERNEL
);
1056 kfree(tty
->write_buf
);
1057 tty
->write_cnt
= chunk
;
1058 tty
->write_buf
= buf_chunk
;
1061 /* Do the write .. */
1063 size_t size
= count
;
1067 if (copy_from_user(tty
->write_buf
, buf
, size
))
1069 ret
= write(tty
, file
, tty
->write_buf
, size
);
1078 if (signal_pending(current
))
1083 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
1084 inode
->i_mtime
= current_fs_time(inode
->i_sb
);
1088 tty_write_unlock(tty
);
1093 * tty_write_message - write a message to a certain tty, not just the console.
1094 * @tty: the destination tty_struct
1095 * @msg: the message to write
1097 * This is used for messages that need to be redirected to a specific tty.
1098 * We don't put it into the syslog queue right now maybe in the future if
1101 * We must still hold the BTM and test the CLOSING flag for the moment.
1104 void tty_write_message(struct tty_struct
*tty
, char *msg
)
1107 mutex_lock(&tty
->atomic_write_lock
);
1109 if (tty
->ops
->write
&& !test_bit(TTY_CLOSING
, &tty
->flags
)) {
1111 tty
->ops
->write(tty
, msg
, strlen(msg
));
1114 tty_write_unlock(tty
);
1121 * tty_write - write method for tty device file
1122 * @file: tty file pointer
1123 * @buf: user data to write
1124 * @count: bytes to write
1127 * Write data to a tty device via the line discipline.
1130 * Locks the line discipline as required
1131 * Writes to the tty driver are serialized by the atomic_write_lock
1132 * and are then processed in chunks to the device. The line discipline
1133 * write method will not be invoked in parallel for each device.
1136 static ssize_t
tty_write(struct file
*file
, const char __user
*buf
,
1137 size_t count
, loff_t
*ppos
)
1139 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
1140 struct tty_struct
*tty
= file_tty(file
);
1141 struct tty_ldisc
*ld
;
1144 if (tty_paranoia_check(tty
, inode
, "tty_write"))
1146 if (!tty
|| !tty
->ops
->write
||
1147 (test_bit(TTY_IO_ERROR
, &tty
->flags
)))
1149 /* Short term debug to catch buggy drivers */
1150 if (tty
->ops
->write_room
== NULL
)
1151 printk(KERN_ERR
"tty driver %s lacks a write_room method.\n",
1153 ld
= tty_ldisc_ref_wait(tty
);
1154 if (!ld
->ops
->write
)
1157 ret
= do_tty_write(ld
->ops
->write
, tty
, file
, buf
, count
);
1158 tty_ldisc_deref(ld
);
1162 ssize_t
redirected_tty_write(struct file
*file
, const char __user
*buf
,
1163 size_t count
, loff_t
*ppos
)
1165 struct file
*p
= NULL
;
1167 spin_lock(&redirect_lock
);
1169 p
= get_file(redirect
);
1170 spin_unlock(&redirect_lock
);
1174 res
= vfs_write(p
, buf
, count
, &p
->f_pos
);
1178 return tty_write(file
, buf
, count
, ppos
);
1181 static char ptychar
[] = "pqrstuvwxyzabcde";
1184 * pty_line_name - generate name for a pty
1185 * @driver: the tty driver in use
1186 * @index: the minor number
1187 * @p: output buffer of at least 6 bytes
1189 * Generate a name from a driver reference and write it to the output
1194 static void pty_line_name(struct tty_driver
*driver
, int index
, char *p
)
1196 int i
= index
+ driver
->name_base
;
1197 /* ->name is initialized to "ttyp", but "tty" is expected */
1198 sprintf(p
, "%s%c%x",
1199 driver
->subtype
== PTY_TYPE_SLAVE
? "tty" : driver
->name
,
1200 ptychar
[i
>> 4 & 0xf], i
& 0xf);
1204 * tty_line_name - generate name for a tty
1205 * @driver: the tty driver in use
1206 * @index: the minor number
1207 * @p: output buffer of at least 7 bytes
1209 * Generate a name from a driver reference and write it to the output
1214 static void tty_line_name(struct tty_driver
*driver
, int index
, char *p
)
1216 if (driver
->flags
& TTY_DRIVER_UNNUMBERED_NODE
)
1217 strcpy(p
, driver
->name
);
1219 sprintf(p
, "%s%d", driver
->name
, index
+ driver
->name_base
);
1223 * tty_driver_lookup_tty() - find an existing tty, if any
1224 * @driver: the driver for the tty
1225 * @idx: the minor number
1227 * Return the tty, if found or ERR_PTR() otherwise.
1229 * Locking: tty_mutex must be held. If tty is found, the mutex must
1230 * be held until the 'fast-open' is also done. Will change once we
1231 * have refcounting in the driver and per driver locking
1233 static struct tty_struct
*tty_driver_lookup_tty(struct tty_driver
*driver
,
1234 struct inode
*inode
, int idx
)
1236 if (driver
->ops
->lookup
)
1237 return driver
->ops
->lookup(driver
, inode
, idx
);
1239 return driver
->ttys
[idx
];
1243 * tty_init_termios - helper for termios setup
1244 * @tty: the tty to set up
1246 * Initialise the termios structures for this tty. Thus runs under
1247 * the tty_mutex currently so we can be relaxed about ordering.
1250 int tty_init_termios(struct tty_struct
*tty
)
1252 struct ktermios
*tp
;
1253 int idx
= tty
->index
;
1255 if (tty
->driver
->flags
& TTY_DRIVER_RESET_TERMIOS
)
1256 tty
->termios
= tty
->driver
->init_termios
;
1258 /* Check for lazy saved data */
1259 tp
= tty
->driver
->termios
[idx
];
1263 tty
->termios
= tty
->driver
->init_termios
;
1265 /* Compatibility until drivers always set this */
1266 tty
->termios
.c_ispeed
= tty_termios_input_baud_rate(&tty
->termios
);
1267 tty
->termios
.c_ospeed
= tty_termios_baud_rate(&tty
->termios
);
1270 EXPORT_SYMBOL_GPL(tty_init_termios
);
1272 int tty_standard_install(struct tty_driver
*driver
, struct tty_struct
*tty
)
1274 int ret
= tty_init_termios(tty
);
1278 tty_driver_kref_get(driver
);
1280 driver
->ttys
[tty
->index
] = tty
;
1283 EXPORT_SYMBOL_GPL(tty_standard_install
);
1286 * tty_driver_install_tty() - install a tty entry in the driver
1287 * @driver: the driver for the tty
1290 * Install a tty object into the driver tables. The tty->index field
1291 * will be set by the time this is called. This method is responsible
1292 * for ensuring any need additional structures are allocated and
1295 * Locking: tty_mutex for now
1297 static int tty_driver_install_tty(struct tty_driver
*driver
,
1298 struct tty_struct
*tty
)
1300 return driver
->ops
->install
? driver
->ops
->install(driver
, tty
) :
1301 tty_standard_install(driver
, tty
);
1305 * tty_driver_remove_tty() - remove a tty from the driver tables
1306 * @driver: the driver for the tty
1307 * @idx: the minor number
1309 * Remvoe a tty object from the driver tables. The tty->index field
1310 * will be set by the time this is called.
1312 * Locking: tty_mutex for now
1314 void tty_driver_remove_tty(struct tty_driver
*driver
, struct tty_struct
*tty
)
1316 if (driver
->ops
->remove
)
1317 driver
->ops
->remove(driver
, tty
);
1319 driver
->ttys
[tty
->index
] = NULL
;
1323 * tty_reopen() - fast re-open of an open tty
1324 * @tty - the tty to open
1326 * Return 0 on success, -errno on error.
1328 * Locking: tty_mutex must be held from the time the tty was found
1329 * till this open completes.
1331 static int tty_reopen(struct tty_struct
*tty
)
1333 struct tty_driver
*driver
= tty
->driver
;
1335 if (test_bit(TTY_CLOSING
, &tty
->flags
) ||
1336 test_bit(TTY_HUPPING
, &tty
->flags
) ||
1337 test_bit(TTY_LDISC_CHANGING
, &tty
->flags
))
1340 if (driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1341 driver
->subtype
== PTY_TYPE_MASTER
) {
1343 * special case for PTY masters: only one open permitted,
1344 * and the slave side open count is incremented as well.
1353 mutex_lock(&tty
->ldisc_mutex
);
1354 WARN_ON(!test_bit(TTY_LDISC
, &tty
->flags
));
1355 mutex_unlock(&tty
->ldisc_mutex
);
1361 * tty_init_dev - initialise a tty device
1362 * @driver: tty driver we are opening a device on
1363 * @idx: device index
1364 * @ret_tty: returned tty structure
1366 * Prepare a tty device. This may not be a "new" clean device but
1367 * could also be an active device. The pty drivers require special
1368 * handling because of this.
1371 * The function is called under the tty_mutex, which
1372 * protects us from the tty struct or driver itself going away.
1374 * On exit the tty device has the line discipline attached and
1375 * a reference count of 1. If a pair was created for pty/tty use
1376 * and the other was a pty master then it too has a reference count of 1.
1378 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1379 * failed open. The new code protects the open with a mutex, so it's
1380 * really quite straightforward. The mutex locking can probably be
1381 * relaxed for the (most common) case of reopening a tty.
1384 struct tty_struct
*tty_init_dev(struct tty_driver
*driver
, int idx
)
1386 struct tty_struct
*tty
;
1390 * First time open is complex, especially for PTY devices.
1391 * This code guarantees that either everything succeeds and the
1392 * TTY is ready for operation, or else the table slots are vacated
1393 * and the allocated memory released. (Except that the termios
1394 * and locked termios may be retained.)
1397 if (!try_module_get(driver
->owner
))
1398 return ERR_PTR(-ENODEV
);
1400 tty
= alloc_tty_struct();
1403 goto err_module_put
;
1405 initialize_tty_struct(tty
, driver
, idx
);
1408 retval
= tty_driver_install_tty(driver
, tty
);
1410 goto err_deinit_tty
;
1413 tty
->port
= driver
->ports
[idx
];
1415 WARN_RATELIMIT(!tty
->port
,
1416 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1417 __func__
, tty
->driver
->name
);
1419 tty
->port
->itty
= tty
;
1422 * Structures all installed ... call the ldisc open routines.
1423 * If we fail here just call release_tty to clean up. No need
1424 * to decrement the use counts, as release_tty doesn't care.
1426 retval
= tty_ldisc_setup(tty
, tty
->link
);
1428 goto err_release_tty
;
1429 /* Return the tty locked so that it cannot vanish under the caller */
1434 deinitialize_tty_struct(tty
);
1435 free_tty_struct(tty
);
1437 module_put(driver
->owner
);
1438 return ERR_PTR(retval
);
1440 /* call the tty release_tty routine to clean out this slot */
1443 printk_ratelimited(KERN_INFO
"tty_init_dev: ldisc open failed, "
1444 "clearing slot %d\n", idx
);
1445 release_tty(tty
, idx
);
1446 return ERR_PTR(retval
);
1449 void tty_free_termios(struct tty_struct
*tty
)
1451 struct ktermios
*tp
;
1452 int idx
= tty
->index
;
1454 /* If the port is going to reset then it has no termios to save */
1455 if (tty
->driver
->flags
& TTY_DRIVER_RESET_TERMIOS
)
1458 /* Stash the termios data */
1459 tp
= tty
->driver
->termios
[idx
];
1461 tp
= kmalloc(sizeof(struct ktermios
), GFP_KERNEL
);
1463 pr_warn("tty: no memory to save termios state.\n");
1466 tty
->driver
->termios
[idx
] = tp
;
1470 EXPORT_SYMBOL(tty_free_termios
);
1474 * release_one_tty - release tty structure memory
1475 * @kref: kref of tty we are obliterating
1477 * Releases memory associated with a tty structure, and clears out the
1478 * driver table slots. This function is called when a device is no longer
1479 * in use. It also gets called when setup of a device fails.
1482 * takes the file list lock internally when working on the list
1483 * of ttys that the driver keeps.
1485 * This method gets called from a work queue so that the driver private
1486 * cleanup ops can sleep (needed for USB at least)
1488 static void release_one_tty(struct work_struct
*work
)
1490 struct tty_struct
*tty
=
1491 container_of(work
, struct tty_struct
, hangup_work
);
1492 struct tty_driver
*driver
= tty
->driver
;
1494 if (tty
->ops
->cleanup
)
1495 tty
->ops
->cleanup(tty
);
1498 tty_driver_kref_put(driver
);
1499 module_put(driver
->owner
);
1501 spin_lock(&tty_files_lock
);
1502 list_del_init(&tty
->tty_files
);
1503 spin_unlock(&tty_files_lock
);
1506 put_pid(tty
->session
);
1507 free_tty_struct(tty
);
1510 static void queue_release_one_tty(struct kref
*kref
)
1512 struct tty_struct
*tty
= container_of(kref
, struct tty_struct
, kref
);
1514 /* The hangup queue is now free so we can reuse it rather than
1515 waste a chunk of memory for each port */
1516 INIT_WORK(&tty
->hangup_work
, release_one_tty
);
1517 schedule_work(&tty
->hangup_work
);
1521 * tty_kref_put - release a tty kref
1524 * Release a reference to a tty device and if need be let the kref
1525 * layer destruct the object for us
1528 void tty_kref_put(struct tty_struct
*tty
)
1531 kref_put(&tty
->kref
, queue_release_one_tty
);
1533 EXPORT_SYMBOL(tty_kref_put
);
1536 * release_tty - release tty structure memory
1538 * Release both @tty and a possible linked partner (think pty pair),
1539 * and decrement the refcount of the backing module.
1543 * takes the file list lock internally when working on the list
1544 * of ttys that the driver keeps.
1547 static void release_tty(struct tty_struct
*tty
, int idx
)
1549 /* This should always be true but check for the moment */
1550 WARN_ON(tty
->index
!= idx
);
1551 WARN_ON(!mutex_is_locked(&tty_mutex
));
1552 if (tty
->ops
->shutdown
)
1553 tty
->ops
->shutdown(tty
);
1554 tty_free_termios(tty
);
1555 tty_driver_remove_tty(tty
->driver
, tty
);
1556 tty
->port
->itty
= NULL
;
1559 tty_kref_put(tty
->link
);
1564 * tty_release_checks - check a tty before real release
1565 * @tty: tty to check
1566 * @o_tty: link of @tty (if any)
1567 * @idx: index of the tty
1569 * Performs some paranoid checking before true release of the @tty.
1570 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1572 static int tty_release_checks(struct tty_struct
*tty
, struct tty_struct
*o_tty
,
1575 #ifdef TTY_PARANOIA_CHECK
1576 if (idx
< 0 || idx
>= tty
->driver
->num
) {
1577 printk(KERN_DEBUG
"%s: bad idx when trying to free (%s)\n",
1578 __func__
, tty
->name
);
1582 /* not much to check for devpts */
1583 if (tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
)
1586 if (tty
!= tty
->driver
->ttys
[idx
]) {
1587 printk(KERN_DEBUG
"%s: driver.table[%d] not tty for (%s)\n",
1588 __func__
, idx
, tty
->name
);
1591 if (tty
->driver
->other
) {
1592 if (o_tty
!= tty
->driver
->other
->ttys
[idx
]) {
1593 printk(KERN_DEBUG
"%s: other->table[%d] not o_tty for (%s)\n",
1594 __func__
, idx
, tty
->name
);
1597 if (o_tty
->link
!= tty
) {
1598 printk(KERN_DEBUG
"%s: bad pty pointers\n", __func__
);
1607 * tty_release - vfs callback for close
1608 * @inode: inode of tty
1609 * @filp: file pointer for handle to tty
1611 * Called the last time each file handle is closed that references
1612 * this tty. There may however be several such references.
1615 * Takes bkl. See tty_release_dev
1617 * Even releasing the tty structures is a tricky business.. We have
1618 * to be very careful that the structures are all released at the
1619 * same time, as interrupts might otherwise get the wrong pointers.
1621 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1622 * lead to double frees or releasing memory still in use.
1625 int tty_release(struct inode
*inode
, struct file
*filp
)
1627 struct tty_struct
*tty
= file_tty(filp
);
1628 struct tty_struct
*o_tty
;
1629 int pty_master
, tty_closing
, o_tty_closing
, do_sleep
;
1633 if (tty_paranoia_check(tty
, inode
, __func__
))
1637 check_tty_count(tty
, __func__
);
1639 __tty_fasync(-1, filp
, 0);
1642 pty_master
= (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1643 tty
->driver
->subtype
== PTY_TYPE_MASTER
);
1644 /* Review: parallel close */
1647 if (tty_release_checks(tty
, o_tty
, idx
)) {
1652 #ifdef TTY_DEBUG_HANGUP
1653 printk(KERN_DEBUG
"%s: %s (tty count=%d)...\n", __func__
,
1654 tty_name(tty
, buf
), tty
->count
);
1657 if (tty
->ops
->close
)
1658 tty
->ops
->close(tty
, filp
);
1662 * Sanity check: if tty->count is going to zero, there shouldn't be
1663 * any waiters on tty->read_wait or tty->write_wait. We test the
1664 * wait queues and kick everyone out _before_ actually starting to
1665 * close. This ensures that we won't block while releasing the tty
1668 * The test for the o_tty closing is necessary, since the master and
1669 * slave sides may close in any order. If the slave side closes out
1670 * first, its count will be one, since the master side holds an open.
1671 * Thus this test wouldn't be triggered at the time the slave closes,
1674 * Note that it's possible for the tty to be opened again while we're
1675 * flushing out waiters. By recalculating the closing flags before
1676 * each iteration we avoid any problems.
1679 /* Guard against races with tty->count changes elsewhere and
1680 opens on /dev/tty */
1682 mutex_lock(&tty_mutex
);
1683 tty_lock_pair(tty
, o_tty
);
1684 tty_closing
= tty
->count
<= 1;
1685 o_tty_closing
= o_tty
&&
1686 (o_tty
->count
<= (pty_master
? 1 : 0));
1690 if (waitqueue_active(&tty
->read_wait
)) {
1691 wake_up_poll(&tty
->read_wait
, POLLIN
);
1694 if (waitqueue_active(&tty
->write_wait
)) {
1695 wake_up_poll(&tty
->write_wait
, POLLOUT
);
1699 if (o_tty_closing
) {
1700 if (waitqueue_active(&o_tty
->read_wait
)) {
1701 wake_up_poll(&o_tty
->read_wait
, POLLIN
);
1704 if (waitqueue_active(&o_tty
->write_wait
)) {
1705 wake_up_poll(&o_tty
->write_wait
, POLLOUT
);
1712 printk(KERN_WARNING
"%s: %s: read/write wait queue active!\n",
1713 __func__
, tty_name(tty
, buf
));
1714 tty_unlock_pair(tty
, o_tty
);
1715 mutex_unlock(&tty_mutex
);
1720 * The closing flags are now consistent with the open counts on
1721 * both sides, and we've completed the last operation that could
1722 * block, so it's safe to proceed with closing.
1724 * We must *not* drop the tty_mutex until we ensure that a further
1725 * entry into tty_open can not pick up this tty.
1728 if (--o_tty
->count
< 0) {
1729 printk(KERN_WARNING
"%s: bad pty slave count (%d) for %s\n",
1730 __func__
, o_tty
->count
, tty_name(o_tty
, buf
));
1734 if (--tty
->count
< 0) {
1735 printk(KERN_WARNING
"%s: bad tty->count (%d) for %s\n",
1736 __func__
, tty
->count
, tty_name(tty
, buf
));
1741 * We've decremented tty->count, so we need to remove this file
1742 * descriptor off the tty->tty_files list; this serves two
1744 * - check_tty_count sees the correct number of file descriptors
1745 * associated with this tty.
1746 * - do_tty_hangup no longer sees this file descriptor as
1747 * something that needs to be handled for hangups.
1752 * Perform some housekeeping before deciding whether to return.
1754 * Set the TTY_CLOSING flag if this was the last open. In the
1755 * case of a pty we may have to wait around for the other side
1756 * to close, and TTY_CLOSING makes sure we can't be reopened.
1759 set_bit(TTY_CLOSING
, &tty
->flags
);
1761 set_bit(TTY_CLOSING
, &o_tty
->flags
);
1764 * If _either_ side is closing, make sure there aren't any
1765 * processes that still think tty or o_tty is their controlling
1768 if (tty_closing
|| o_tty_closing
) {
1769 read_lock(&tasklist_lock
);
1770 session_clear_tty(tty
->session
);
1772 session_clear_tty(o_tty
->session
);
1773 read_unlock(&tasklist_lock
);
1776 mutex_unlock(&tty_mutex
);
1777 tty_unlock_pair(tty
, o_tty
);
1778 /* At this point the TTY_CLOSING flag should ensure a dead tty
1779 cannot be re-opened by a racing opener */
1781 /* check whether both sides are closing ... */
1782 if (!tty_closing
|| (o_tty
&& !o_tty_closing
))
1785 #ifdef TTY_DEBUG_HANGUP
1786 printk(KERN_DEBUG
"%s: freeing tty structure...\n", __func__
);
1789 * Ask the line discipline code to release its structures
1791 tty_ldisc_release(tty
, o_tty
);
1793 * The release_tty function takes care of the details of clearing
1794 * the slots and preserving the termios structure. The tty_unlock_pair
1795 * should be safe as we keep a kref while the tty is locked (so the
1796 * unlock never unlocks a freed tty).
1798 mutex_lock(&tty_mutex
);
1799 release_tty(tty
, idx
);
1800 mutex_unlock(&tty_mutex
);
1806 * tty_open_current_tty - get tty of current task for open
1807 * @device: device number
1808 * @filp: file pointer to tty
1809 * @return: tty of the current task iff @device is /dev/tty
1811 * We cannot return driver and index like for the other nodes because
1812 * devpts will not work then. It expects inodes to be from devpts FS.
1814 * We need to move to returning a refcounted object from all the lookup
1815 * paths including this one.
1817 static struct tty_struct
*tty_open_current_tty(dev_t device
, struct file
*filp
)
1819 struct tty_struct
*tty
;
1821 if (device
!= MKDEV(TTYAUX_MAJOR
, 0))
1824 tty
= get_current_tty();
1826 return ERR_PTR(-ENXIO
);
1828 filp
->f_flags
|= O_NONBLOCK
; /* Don't let /dev/tty block */
1831 /* FIXME: we put a reference and return a TTY! */
1832 /* This is only safe because the caller holds tty_mutex */
1837 * tty_lookup_driver - lookup a tty driver for a given device file
1838 * @device: device number
1839 * @filp: file pointer to tty
1840 * @noctty: set if the device should not become a controlling tty
1841 * @index: index for the device in the @return driver
1842 * @return: driver for this inode (with increased refcount)
1844 * If @return is not erroneous, the caller is responsible to decrement the
1845 * refcount by tty_driver_kref_put.
1847 * Locking: tty_mutex protects get_tty_driver
1849 static struct tty_driver
*tty_lookup_driver(dev_t device
, struct file
*filp
,
1850 int *noctty
, int *index
)
1852 struct tty_driver
*driver
;
1856 case MKDEV(TTY_MAJOR
, 0): {
1857 extern struct tty_driver
*console_driver
;
1858 driver
= tty_driver_kref_get(console_driver
);
1859 *index
= fg_console
;
1864 case MKDEV(TTYAUX_MAJOR
, 1): {
1865 struct tty_driver
*console_driver
= console_device(index
);
1866 if (console_driver
) {
1867 driver
= tty_driver_kref_get(console_driver
);
1869 /* Don't let /dev/console block */
1870 filp
->f_flags
|= O_NONBLOCK
;
1875 return ERR_PTR(-ENODEV
);
1878 driver
= get_tty_driver(device
, index
);
1880 return ERR_PTR(-ENODEV
);
1887 * tty_open - open a tty device
1888 * @inode: inode of device file
1889 * @filp: file pointer to tty
1891 * tty_open and tty_release keep up the tty count that contains the
1892 * number of opens done on a tty. We cannot use the inode-count, as
1893 * different inodes might point to the same tty.
1895 * Open-counting is needed for pty masters, as well as for keeping
1896 * track of serial lines: DTR is dropped when the last close happens.
1897 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1899 * The termios state of a pty is reset on first open so that
1900 * settings don't persist across reuse.
1902 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
1903 * tty->count should protect the rest.
1904 * ->siglock protects ->signal/->sighand
1906 * Note: the tty_unlock/lock cases without a ref are only safe due to
1910 static int tty_open(struct inode
*inode
, struct file
*filp
)
1912 struct tty_struct
*tty
;
1914 struct tty_driver
*driver
= NULL
;
1916 dev_t device
= inode
->i_rdev
;
1917 unsigned saved_flags
= filp
->f_flags
;
1919 nonseekable_open(inode
, filp
);
1922 retval
= tty_alloc_file(filp
);
1926 noctty
= filp
->f_flags
& O_NOCTTY
;
1930 mutex_lock(&tty_mutex
);
1931 /* This is protected by the tty_mutex */
1932 tty
= tty_open_current_tty(device
, filp
);
1934 retval
= PTR_ERR(tty
);
1937 driver
= tty_lookup_driver(device
, filp
, &noctty
, &index
);
1938 if (IS_ERR(driver
)) {
1939 retval
= PTR_ERR(driver
);
1943 /* check whether we're reopening an existing tty */
1944 tty
= tty_driver_lookup_tty(driver
, inode
, index
);
1946 retval
= PTR_ERR(tty
);
1953 retval
= tty_reopen(tty
);
1956 tty
= ERR_PTR(retval
);
1958 } else /* Returns with the tty_lock held for now */
1959 tty
= tty_init_dev(driver
, index
);
1961 mutex_unlock(&tty_mutex
);
1963 tty_driver_kref_put(driver
);
1965 retval
= PTR_ERR(tty
);
1969 tty_add_file(tty
, filp
);
1971 check_tty_count(tty
, __func__
);
1972 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1973 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
1975 #ifdef TTY_DEBUG_HANGUP
1976 printk(KERN_DEBUG
"%s: opening %s...\n", __func__
, tty
->name
);
1979 retval
= tty
->ops
->open(tty
, filp
);
1982 filp
->f_flags
= saved_flags
;
1984 if (!retval
&& test_bit(TTY_EXCLUSIVE
, &tty
->flags
) &&
1985 !capable(CAP_SYS_ADMIN
))
1989 #ifdef TTY_DEBUG_HANGUP
1990 printk(KERN_DEBUG
"%s: error %d in opening %s...\n", __func__
,
1993 tty_unlock(tty
); /* need to call tty_release without BTM */
1994 tty_release(inode
, filp
);
1995 if (retval
!= -ERESTARTSYS
)
1998 if (signal_pending(current
))
2003 * Need to reset f_op in case a hangup happened.
2005 if (filp
->f_op
== &hung_up_tty_fops
)
2006 filp
->f_op
= &tty_fops
;
2012 mutex_lock(&tty_mutex
);
2014 spin_lock_irq(¤t
->sighand
->siglock
);
2016 current
->signal
->leader
&&
2017 !current
->signal
->tty
&&
2018 tty
->session
== NULL
)
2019 __proc_set_tty(current
, tty
);
2020 spin_unlock_irq(¤t
->sighand
->siglock
);
2022 mutex_unlock(&tty_mutex
);
2025 mutex_unlock(&tty_mutex
);
2026 /* after locks to avoid deadlock */
2027 if (!IS_ERR_OR_NULL(driver
))
2028 tty_driver_kref_put(driver
);
2030 tty_free_file(filp
);
2037 * tty_poll - check tty status
2038 * @filp: file being polled
2039 * @wait: poll wait structures to update
2041 * Call the line discipline polling method to obtain the poll
2042 * status of the device.
2044 * Locking: locks called line discipline but ldisc poll method
2045 * may be re-entered freely by other callers.
2048 static unsigned int tty_poll(struct file
*filp
, poll_table
*wait
)
2050 struct tty_struct
*tty
= file_tty(filp
);
2051 struct tty_ldisc
*ld
;
2054 if (tty_paranoia_check(tty
, filp
->f_path
.dentry
->d_inode
, "tty_poll"))
2057 ld
= tty_ldisc_ref_wait(tty
);
2059 ret
= (ld
->ops
->poll
)(tty
, filp
, wait
);
2060 tty_ldisc_deref(ld
);
2064 static int __tty_fasync(int fd
, struct file
*filp
, int on
)
2066 struct tty_struct
*tty
= file_tty(filp
);
2067 unsigned long flags
;
2070 if (tty_paranoia_check(tty
, filp
->f_path
.dentry
->d_inode
, "tty_fasync"))
2073 retval
= fasync_helper(fd
, filp
, on
, &tty
->fasync
);
2080 if (!waitqueue_active(&tty
->read_wait
))
2081 tty
->minimum_to_wake
= 1;
2082 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2085 type
= PIDTYPE_PGID
;
2087 pid
= task_pid(current
);
2091 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2092 retval
= __f_setown(filp
, pid
, type
, 0);
2097 if (!tty
->fasync
&& !waitqueue_active(&tty
->read_wait
))
2098 tty
->minimum_to_wake
= N_TTY_BUF_SIZE
;
2105 static int tty_fasync(int fd
, struct file
*filp
, int on
)
2107 struct tty_struct
*tty
= file_tty(filp
);
2111 retval
= __tty_fasync(fd
, filp
, on
);
2118 * tiocsti - fake input character
2119 * @tty: tty to fake input into
2120 * @p: pointer to character
2122 * Fake input to a tty device. Does the necessary locking and
2125 * FIXME: does not honour flow control ??
2128 * Called functions take tty_ldisc_lock
2129 * current->signal->tty check is safe without locks
2131 * FIXME: may race normal receive processing
2134 static int tiocsti(struct tty_struct
*tty
, char __user
*p
)
2137 struct tty_ldisc
*ld
;
2139 if ((current
->signal
->tty
!= tty
) && !capable(CAP_SYS_ADMIN
))
2141 if (get_user(ch
, p
))
2143 tty_audit_tiocsti(tty
, ch
);
2144 ld
= tty_ldisc_ref_wait(tty
);
2145 ld
->ops
->receive_buf(tty
, &ch
, &mbz
, 1);
2146 tty_ldisc_deref(ld
);
2151 * tiocgwinsz - implement window query ioctl
2153 * @arg: user buffer for result
2155 * Copies the kernel idea of the window size into the user buffer.
2157 * Locking: tty->termios_mutex is taken to ensure the winsize data
2161 static int tiocgwinsz(struct tty_struct
*tty
, struct winsize __user
*arg
)
2165 mutex_lock(&tty
->termios_mutex
);
2166 err
= copy_to_user(arg
, &tty
->winsize
, sizeof(*arg
));
2167 mutex_unlock(&tty
->termios_mutex
);
2169 return err
? -EFAULT
: 0;
2173 * tty_do_resize - resize event
2174 * @tty: tty being resized
2175 * @rows: rows (character)
2176 * @cols: cols (character)
2178 * Update the termios variables and send the necessary signals to
2179 * peform a terminal resize correctly
2182 int tty_do_resize(struct tty_struct
*tty
, struct winsize
*ws
)
2185 unsigned long flags
;
2188 mutex_lock(&tty
->termios_mutex
);
2189 if (!memcmp(ws
, &tty
->winsize
, sizeof(*ws
)))
2191 /* Get the PID values and reference them so we can
2192 avoid holding the tty ctrl lock while sending signals */
2193 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2194 pgrp
= get_pid(tty
->pgrp
);
2195 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2198 kill_pgrp(pgrp
, SIGWINCH
, 1);
2203 mutex_unlock(&tty
->termios_mutex
);
2208 * tiocswinsz - implement window size set ioctl
2209 * @tty; tty side of tty
2210 * @arg: user buffer for result
2212 * Copies the user idea of the window size to the kernel. Traditionally
2213 * this is just advisory information but for the Linux console it
2214 * actually has driver level meaning and triggers a VC resize.
2217 * Driver dependent. The default do_resize method takes the
2218 * tty termios mutex and ctrl_lock. The console takes its own lock
2219 * then calls into the default method.
2222 static int tiocswinsz(struct tty_struct
*tty
, struct winsize __user
*arg
)
2224 struct winsize tmp_ws
;
2225 if (copy_from_user(&tmp_ws
, arg
, sizeof(*arg
)))
2228 if (tty
->ops
->resize
)
2229 return tty
->ops
->resize(tty
, &tmp_ws
);
2231 return tty_do_resize(tty
, &tmp_ws
);
2235 * tioccons - allow admin to move logical console
2236 * @file: the file to become console
2238 * Allow the administrator to move the redirected console device
2240 * Locking: uses redirect_lock to guard the redirect information
2243 static int tioccons(struct file
*file
)
2245 if (!capable(CAP_SYS_ADMIN
))
2247 if (file
->f_op
->write
== redirected_tty_write
) {
2249 spin_lock(&redirect_lock
);
2252 spin_unlock(&redirect_lock
);
2257 spin_lock(&redirect_lock
);
2259 spin_unlock(&redirect_lock
);
2262 redirect
= get_file(file
);
2263 spin_unlock(&redirect_lock
);
2268 * fionbio - non blocking ioctl
2269 * @file: file to set blocking value
2270 * @p: user parameter
2272 * Historical tty interfaces had a blocking control ioctl before
2273 * the generic functionality existed. This piece of history is preserved
2274 * in the expected tty API of posix OS's.
2276 * Locking: none, the open file handle ensures it won't go away.
2279 static int fionbio(struct file
*file
, int __user
*p
)
2283 if (get_user(nonblock
, p
))
2286 spin_lock(&file
->f_lock
);
2288 file
->f_flags
|= O_NONBLOCK
;
2290 file
->f_flags
&= ~O_NONBLOCK
;
2291 spin_unlock(&file
->f_lock
);
2296 * tiocsctty - set controlling tty
2297 * @tty: tty structure
2298 * @arg: user argument
2300 * This ioctl is used to manage job control. It permits a session
2301 * leader to set this tty as the controlling tty for the session.
2304 * Takes tty_mutex() to protect tty instance
2305 * Takes tasklist_lock internally to walk sessions
2306 * Takes ->siglock() when updating signal->tty
2309 static int tiocsctty(struct tty_struct
*tty
, int arg
)
2312 if (current
->signal
->leader
&& (task_session(current
) == tty
->session
))
2315 mutex_lock(&tty_mutex
);
2317 * The process must be a session leader and
2318 * not have a controlling tty already.
2320 if (!current
->signal
->leader
|| current
->signal
->tty
) {
2327 * This tty is already the controlling
2328 * tty for another session group!
2330 if (arg
== 1 && capable(CAP_SYS_ADMIN
)) {
2334 read_lock(&tasklist_lock
);
2335 session_clear_tty(tty
->session
);
2336 read_unlock(&tasklist_lock
);
2342 proc_set_tty(current
, tty
);
2344 mutex_unlock(&tty_mutex
);
2349 * tty_get_pgrp - return a ref counted pgrp pid
2352 * Returns a refcounted instance of the pid struct for the process
2353 * group controlling the tty.
2356 struct pid
*tty_get_pgrp(struct tty_struct
*tty
)
2358 unsigned long flags
;
2361 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2362 pgrp
= get_pid(tty
->pgrp
);
2363 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2367 EXPORT_SYMBOL_GPL(tty_get_pgrp
);
2370 * tiocgpgrp - get process group
2371 * @tty: tty passed by user
2372 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2375 * Obtain the process group of the tty. If there is no process group
2378 * Locking: none. Reference to current->signal->tty is safe.
2381 static int tiocgpgrp(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
2386 * (tty == real_tty) is a cheap way of
2387 * testing if the tty is NOT a master pty.
2389 if (tty
== real_tty
&& current
->signal
->tty
!= real_tty
)
2391 pid
= tty_get_pgrp(real_tty
);
2392 ret
= put_user(pid_vnr(pid
), p
);
2398 * tiocspgrp - attempt to set process group
2399 * @tty: tty passed by user
2400 * @real_tty: tty side device matching tty passed by user
2403 * Set the process group of the tty to the session passed. Only
2404 * permitted where the tty session is our session.
2406 * Locking: RCU, ctrl lock
2409 static int tiocspgrp(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
2413 int retval
= tty_check_change(real_tty
);
2414 unsigned long flags
;
2420 if (!current
->signal
->tty
||
2421 (current
->signal
->tty
!= real_tty
) ||
2422 (real_tty
->session
!= task_session(current
)))
2424 if (get_user(pgrp_nr
, p
))
2429 pgrp
= find_vpid(pgrp_nr
);
2434 if (session_of_pgrp(pgrp
) != task_session(current
))
2437 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2438 put_pid(real_tty
->pgrp
);
2439 real_tty
->pgrp
= get_pid(pgrp
);
2440 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2447 * tiocgsid - get session id
2448 * @tty: tty passed by user
2449 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2450 * @p: pointer to returned session id
2452 * Obtain the session id of the tty. If there is no session
2455 * Locking: none. Reference to current->signal->tty is safe.
2458 static int tiocgsid(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
2461 * (tty == real_tty) is a cheap way of
2462 * testing if the tty is NOT a master pty.
2464 if (tty
== real_tty
&& current
->signal
->tty
!= real_tty
)
2466 if (!real_tty
->session
)
2468 return put_user(pid_vnr(real_tty
->session
), p
);
2472 * tiocsetd - set line discipline
2474 * @p: pointer to user data
2476 * Set the line discipline according to user request.
2478 * Locking: see tty_set_ldisc, this function is just a helper
2481 static int tiocsetd(struct tty_struct
*tty
, int __user
*p
)
2486 if (get_user(ldisc
, p
))
2489 ret
= tty_set_ldisc(tty
, ldisc
);
2495 * send_break - performed time break
2496 * @tty: device to break on
2497 * @duration: timeout in mS
2499 * Perform a timed break on hardware that lacks its own driver level
2500 * timed break functionality.
2503 * atomic_write_lock serializes
2507 static int send_break(struct tty_struct
*tty
, unsigned int duration
)
2511 if (tty
->ops
->break_ctl
== NULL
)
2514 if (tty
->driver
->flags
& TTY_DRIVER_HARDWARE_BREAK
)
2515 retval
= tty
->ops
->break_ctl(tty
, duration
);
2517 /* Do the work ourselves */
2518 if (tty_write_lock(tty
, 0) < 0)
2520 retval
= tty
->ops
->break_ctl(tty
, -1);
2523 if (!signal_pending(current
))
2524 msleep_interruptible(duration
);
2525 retval
= tty
->ops
->break_ctl(tty
, 0);
2527 tty_write_unlock(tty
);
2528 if (signal_pending(current
))
2535 * tty_tiocmget - get modem status
2537 * @file: user file pointer
2538 * @p: pointer to result
2540 * Obtain the modem status bits from the tty driver if the feature
2541 * is supported. Return -EINVAL if it is not available.
2543 * Locking: none (up to the driver)
2546 static int tty_tiocmget(struct tty_struct
*tty
, int __user
*p
)
2548 int retval
= -EINVAL
;
2550 if (tty
->ops
->tiocmget
) {
2551 retval
= tty
->ops
->tiocmget(tty
);
2554 retval
= put_user(retval
, p
);
2560 * tty_tiocmset - set modem status
2562 * @cmd: command - clear bits, set bits or set all
2563 * @p: pointer to desired bits
2565 * Set the modem status bits from the tty driver if the feature
2566 * is supported. Return -EINVAL if it is not available.
2568 * Locking: none (up to the driver)
2571 static int tty_tiocmset(struct tty_struct
*tty
, unsigned int cmd
,
2575 unsigned int set
, clear
, val
;
2577 if (tty
->ops
->tiocmset
== NULL
)
2580 retval
= get_user(val
, p
);
2596 set
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
2597 clear
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
2598 return tty
->ops
->tiocmset(tty
, set
, clear
);
2601 static int tty_tiocgicount(struct tty_struct
*tty
, void __user
*arg
)
2603 int retval
= -EINVAL
;
2604 struct serial_icounter_struct icount
;
2605 memset(&icount
, 0, sizeof(icount
));
2606 if (tty
->ops
->get_icount
)
2607 retval
= tty
->ops
->get_icount(tty
, &icount
);
2610 if (copy_to_user(arg
, &icount
, sizeof(icount
)))
2615 struct tty_struct
*tty_pair_get_tty(struct tty_struct
*tty
)
2617 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2618 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
2622 EXPORT_SYMBOL(tty_pair_get_tty
);
2624 struct tty_struct
*tty_pair_get_pty(struct tty_struct
*tty
)
2626 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2627 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
2631 EXPORT_SYMBOL(tty_pair_get_pty
);
2634 * Split this up, as gcc can choke on it otherwise..
2636 long tty_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
2638 struct tty_struct
*tty
= file_tty(file
);
2639 struct tty_struct
*real_tty
;
2640 void __user
*p
= (void __user
*)arg
;
2642 struct tty_ldisc
*ld
;
2643 struct inode
*inode
= file
->f_dentry
->d_inode
;
2645 if (tty_paranoia_check(tty
, inode
, "tty_ioctl"))
2648 real_tty
= tty_pair_get_tty(tty
);
2651 * Factor out some common prep work
2659 retval
= tty_check_change(tty
);
2662 if (cmd
!= TIOCCBRK
) {
2663 tty_wait_until_sent(tty
, 0);
2664 if (signal_pending(current
))
2675 return tiocsti(tty
, p
);
2677 return tiocgwinsz(real_tty
, p
);
2679 return tiocswinsz(real_tty
, p
);
2681 return real_tty
!= tty
? -EINVAL
: tioccons(file
);
2683 return fionbio(file
, p
);
2685 set_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2688 clear_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2692 int excl
= test_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2693 return put_user(excl
, (int __user
*)p
);
2696 if (current
->signal
->tty
!= tty
)
2701 return tiocsctty(tty
, arg
);
2703 return tiocgpgrp(tty
, real_tty
, p
);
2705 return tiocspgrp(tty
, real_tty
, p
);
2707 return tiocgsid(tty
, real_tty
, p
);
2709 return put_user(tty
->ldisc
->ops
->num
, (int __user
*)p
);
2711 return tiocsetd(tty
, p
);
2713 if (!capable(CAP_SYS_ADMIN
))
2719 unsigned int ret
= new_encode_dev(tty_devnum(real_tty
));
2720 return put_user(ret
, (unsigned int __user
*)p
);
2725 case TIOCSBRK
: /* Turn break on, unconditionally */
2726 if (tty
->ops
->break_ctl
)
2727 return tty
->ops
->break_ctl(tty
, -1);
2729 case TIOCCBRK
: /* Turn break off, unconditionally */
2730 if (tty
->ops
->break_ctl
)
2731 return tty
->ops
->break_ctl(tty
, 0);
2733 case TCSBRK
: /* SVID version: non-zero arg --> no break */
2734 /* non-zero arg means wait for all output data
2735 * to be sent (performed above) but don't send break.
2736 * This is used by the tcdrain() termios function.
2739 return send_break(tty
, 250);
2741 case TCSBRKP
: /* support for POSIX tcsendbreak() */
2742 return send_break(tty
, arg
? arg
*100 : 250);
2745 return tty_tiocmget(tty
, p
);
2749 return tty_tiocmset(tty
, cmd
, p
);
2751 retval
= tty_tiocgicount(tty
, p
);
2752 /* For the moment allow fall through to the old method */
2753 if (retval
!= -EINVAL
)
2760 /* flush tty buffer and allow ldisc to process ioctl */
2761 tty_buffer_flush(tty
);
2766 if (tty
->ops
->ioctl
) {
2767 retval
= (tty
->ops
->ioctl
)(tty
, cmd
, arg
);
2768 if (retval
!= -ENOIOCTLCMD
)
2771 ld
= tty_ldisc_ref_wait(tty
);
2773 if (ld
->ops
->ioctl
) {
2774 retval
= ld
->ops
->ioctl(tty
, file
, cmd
, arg
);
2775 if (retval
== -ENOIOCTLCMD
)
2778 tty_ldisc_deref(ld
);
2782 #ifdef CONFIG_COMPAT
2783 static long tty_compat_ioctl(struct file
*file
, unsigned int cmd
,
2786 struct inode
*inode
= file
->f_dentry
->d_inode
;
2787 struct tty_struct
*tty
= file_tty(file
);
2788 struct tty_ldisc
*ld
;
2789 int retval
= -ENOIOCTLCMD
;
2791 if (tty_paranoia_check(tty
, inode
, "tty_ioctl"))
2794 if (tty
->ops
->compat_ioctl
) {
2795 retval
= (tty
->ops
->compat_ioctl
)(tty
, cmd
, arg
);
2796 if (retval
!= -ENOIOCTLCMD
)
2800 ld
= tty_ldisc_ref_wait(tty
);
2801 if (ld
->ops
->compat_ioctl
)
2802 retval
= ld
->ops
->compat_ioctl(tty
, file
, cmd
, arg
);
2804 retval
= n_tty_compat_ioctl_helper(tty
, file
, cmd
, arg
);
2805 tty_ldisc_deref(ld
);
2811 static int this_tty(const void *t
, struct file
*file
, unsigned fd
)
2813 if (likely(file
->f_op
->read
!= tty_read
))
2815 return file_tty(file
) != t
? 0 : fd
+ 1;
2819 * This implements the "Secure Attention Key" --- the idea is to
2820 * prevent trojan horses by killing all processes associated with this
2821 * tty when the user hits the "Secure Attention Key". Required for
2822 * super-paranoid applications --- see the Orange Book for more details.
2824 * This code could be nicer; ideally it should send a HUP, wait a few
2825 * seconds, then send a INT, and then a KILL signal. But you then
2826 * have to coordinate with the init process, since all processes associated
2827 * with the current tty must be dead before the new getty is allowed
2830 * Now, if it would be correct ;-/ The current code has a nasty hole -
2831 * it doesn't catch files in flight. We may send the descriptor to ourselves
2832 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2834 * Nasty bug: do_SAK is being called in interrupt context. This can
2835 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2837 void __do_SAK(struct tty_struct
*tty
)
2842 struct task_struct
*g
, *p
;
2843 struct pid
*session
;
2848 session
= tty
->session
;
2850 tty_ldisc_flush(tty
);
2852 tty_driver_flush_buffer(tty
);
2854 read_lock(&tasklist_lock
);
2855 /* Kill the entire session */
2856 do_each_pid_task(session
, PIDTYPE_SID
, p
) {
2857 printk(KERN_NOTICE
"SAK: killed process %d"
2858 " (%s): task_session(p)==tty->session\n",
2859 task_pid_nr(p
), p
->comm
);
2860 send_sig(SIGKILL
, p
, 1);
2861 } while_each_pid_task(session
, PIDTYPE_SID
, p
);
2862 /* Now kill any processes that happen to have the
2865 do_each_thread(g
, p
) {
2866 if (p
->signal
->tty
== tty
) {
2867 printk(KERN_NOTICE
"SAK: killed process %d"
2868 " (%s): task_session(p)==tty->session\n",
2869 task_pid_nr(p
), p
->comm
);
2870 send_sig(SIGKILL
, p
, 1);
2874 i
= iterate_fd(p
->files
, 0, this_tty
, tty
);
2876 printk(KERN_NOTICE
"SAK: killed process %d"
2877 " (%s): fd#%d opened to the tty\n",
2878 task_pid_nr(p
), p
->comm
, i
- 1);
2879 force_sig(SIGKILL
, p
);
2882 } while_each_thread(g
, p
);
2883 read_unlock(&tasklist_lock
);
2887 static void do_SAK_work(struct work_struct
*work
)
2889 struct tty_struct
*tty
=
2890 container_of(work
, struct tty_struct
, SAK_work
);
2895 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2896 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2897 * the values which we write to it will be identical to the values which it
2898 * already has. --akpm
2900 void do_SAK(struct tty_struct
*tty
)
2904 schedule_work(&tty
->SAK_work
);
2907 EXPORT_SYMBOL(do_SAK
);
2909 static int dev_match_devt(struct device
*dev
, void *data
)
2912 return dev
->devt
== *devt
;
2915 /* Must put_device() after it's unused! */
2916 static struct device
*tty_get_device(struct tty_struct
*tty
)
2918 dev_t devt
= tty_devnum(tty
);
2919 return class_find_device(tty_class
, NULL
, &devt
, dev_match_devt
);
2924 * initialize_tty_struct
2925 * @tty: tty to initialize
2927 * This subroutine initializes a tty structure that has been newly
2930 * Locking: none - tty in question must not be exposed at this point
2933 void initialize_tty_struct(struct tty_struct
*tty
,
2934 struct tty_driver
*driver
, int idx
)
2936 memset(tty
, 0, sizeof(struct tty_struct
));
2937 kref_init(&tty
->kref
);
2938 tty
->magic
= TTY_MAGIC
;
2939 tty_ldisc_init(tty
);
2940 tty
->session
= NULL
;
2942 mutex_init(&tty
->legacy_mutex
);
2943 mutex_init(&tty
->termios_mutex
);
2944 mutex_init(&tty
->ldisc_mutex
);
2945 init_waitqueue_head(&tty
->write_wait
);
2946 init_waitqueue_head(&tty
->read_wait
);
2947 INIT_WORK(&tty
->hangup_work
, do_tty_hangup
);
2948 mutex_init(&tty
->atomic_write_lock
);
2949 spin_lock_init(&tty
->ctrl_lock
);
2950 INIT_LIST_HEAD(&tty
->tty_files
);
2951 INIT_WORK(&tty
->SAK_work
, do_SAK_work
);
2953 tty
->driver
= driver
;
2954 tty
->ops
= driver
->ops
;
2956 tty_line_name(driver
, idx
, tty
->name
);
2957 tty
->dev
= tty_get_device(tty
);
2961 * deinitialize_tty_struct
2962 * @tty: tty to deinitialize
2964 * This subroutine deinitializes a tty structure that has been newly
2965 * allocated but tty_release cannot be called on that yet.
2967 * Locking: none - tty in question must not be exposed at this point
2969 void deinitialize_tty_struct(struct tty_struct
*tty
)
2971 tty_ldisc_deinit(tty
);
2975 * tty_put_char - write one character to a tty
2979 * Write one byte to the tty using the provided put_char method
2980 * if present. Returns the number of characters successfully output.
2982 * Note: the specific put_char operation in the driver layer may go
2983 * away soon. Don't call it directly, use this method
2986 int tty_put_char(struct tty_struct
*tty
, unsigned char ch
)
2988 if (tty
->ops
->put_char
)
2989 return tty
->ops
->put_char(tty
, ch
);
2990 return tty
->ops
->write(tty
, &ch
, 1);
2992 EXPORT_SYMBOL_GPL(tty_put_char
);
2994 struct class *tty_class
;
2996 static int tty_cdev_add(struct tty_driver
*driver
, dev_t dev
,
2997 unsigned int index
, unsigned int count
)
2999 /* init here, since reused cdevs cause crashes */
3000 cdev_init(&driver
->cdevs
[index
], &tty_fops
);
3001 driver
->cdevs
[index
].owner
= driver
->owner
;
3002 return cdev_add(&driver
->cdevs
[index
], dev
, count
);
3006 * tty_register_device - register a tty device
3007 * @driver: the tty driver that describes the tty device
3008 * @index: the index in the tty driver for this tty device
3009 * @device: a struct device that is associated with this tty device.
3010 * This field is optional, if there is no known struct device
3011 * for this tty device it can be set to NULL safely.
3013 * Returns a pointer to the struct device for this tty device
3014 * (or ERR_PTR(-EFOO) on error).
3016 * This call is required to be made to register an individual tty device
3017 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3018 * that bit is not set, this function should not be called by a tty
3024 struct device
*tty_register_device(struct tty_driver
*driver
, unsigned index
,
3025 struct device
*device
)
3027 return tty_register_device_attr(driver
, index
, device
, NULL
, NULL
);
3029 EXPORT_SYMBOL(tty_register_device
);
3031 static void tty_device_create_release(struct device
*dev
)
3033 pr_debug("device: '%s': %s\n", dev_name(dev
), __func__
);
3038 * tty_register_device_attr - register a tty device
3039 * @driver: the tty driver that describes the tty device
3040 * @index: the index in the tty driver for this tty device
3041 * @device: a struct device that is associated with this tty device.
3042 * This field is optional, if there is no known struct device
3043 * for this tty device it can be set to NULL safely.
3044 * @drvdata: Driver data to be set to device.
3045 * @attr_grp: Attribute group to be set on device.
3047 * Returns a pointer to the struct device for this tty device
3048 * (or ERR_PTR(-EFOO) on error).
3050 * This call is required to be made to register an individual tty device
3051 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3052 * that bit is not set, this function should not be called by a tty
3057 struct device
*tty_register_device_attr(struct tty_driver
*driver
,
3058 unsigned index
, struct device
*device
,
3060 const struct attribute_group
**attr_grp
)
3063 dev_t devt
= MKDEV(driver
->major
, driver
->minor_start
) + index
;
3064 struct device
*dev
= NULL
;
3065 int retval
= -ENODEV
;
3068 if (index
>= driver
->num
) {
3069 printk(KERN_ERR
"Attempt to register invalid tty line number "
3071 return ERR_PTR(-EINVAL
);
3074 if (driver
->type
== TTY_DRIVER_TYPE_PTY
)
3075 pty_line_name(driver
, index
, name
);
3077 tty_line_name(driver
, index
, name
);
3079 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
)) {
3080 retval
= tty_cdev_add(driver
, devt
, index
, 1);
3086 dev
= kzalloc(sizeof(*dev
), GFP_KERNEL
);
3093 dev
->class = tty_class
;
3094 dev
->parent
= device
;
3095 dev
->release
= tty_device_create_release
;
3096 dev_set_name(dev
, "%s", name
);
3097 dev
->groups
= attr_grp
;
3098 dev_set_drvdata(dev
, drvdata
);
3100 retval
= device_register(dev
);
3109 cdev_del(&driver
->cdevs
[index
]);
3110 return ERR_PTR(retval
);
3112 EXPORT_SYMBOL_GPL(tty_register_device_attr
);
3115 * tty_unregister_device - unregister a tty device
3116 * @driver: the tty driver that describes the tty device
3117 * @index: the index in the tty driver for this tty device
3119 * If a tty device is registered with a call to tty_register_device() then
3120 * this function must be called when the tty device is gone.
3125 void tty_unregister_device(struct tty_driver
*driver
, unsigned index
)
3127 device_destroy(tty_class
,
3128 MKDEV(driver
->major
, driver
->minor_start
) + index
);
3129 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
))
3130 cdev_del(&driver
->cdevs
[index
]);
3132 EXPORT_SYMBOL(tty_unregister_device
);
3135 * __tty_alloc_driver -- allocate tty driver
3136 * @lines: count of lines this driver can handle at most
3137 * @owner: module which is repsonsible for this driver
3138 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3140 * This should not be called directly, some of the provided macros should be
3141 * used instead. Use IS_ERR and friends on @retval.
3143 struct tty_driver
*__tty_alloc_driver(unsigned int lines
, struct module
*owner
,
3144 unsigned long flags
)
3146 struct tty_driver
*driver
;
3147 unsigned int cdevs
= 1;
3150 if (!lines
|| (flags
& TTY_DRIVER_UNNUMBERED_NODE
&& lines
> 1))
3151 return ERR_PTR(-EINVAL
);
3153 driver
= kzalloc(sizeof(struct tty_driver
), GFP_KERNEL
);
3155 return ERR_PTR(-ENOMEM
);
3157 kref_init(&driver
->kref
);
3158 driver
->magic
= TTY_DRIVER_MAGIC
;
3159 driver
->num
= lines
;
3160 driver
->owner
= owner
;
3161 driver
->flags
= flags
;
3163 if (!(flags
& TTY_DRIVER_DEVPTS_MEM
)) {
3164 driver
->ttys
= kcalloc(lines
, sizeof(*driver
->ttys
),
3166 driver
->termios
= kcalloc(lines
, sizeof(*driver
->termios
),
3168 if (!driver
->ttys
|| !driver
->termios
) {
3174 if (!(flags
& TTY_DRIVER_DYNAMIC_ALLOC
)) {
3175 driver
->ports
= kcalloc(lines
, sizeof(*driver
->ports
),
3177 if (!driver
->ports
) {
3184 driver
->cdevs
= kcalloc(cdevs
, sizeof(*driver
->cdevs
), GFP_KERNEL
);
3185 if (!driver
->cdevs
) {
3192 kfree(driver
->ports
);
3193 kfree(driver
->ttys
);
3194 kfree(driver
->termios
);
3196 return ERR_PTR(err
);
3198 EXPORT_SYMBOL(__tty_alloc_driver
);
3200 static void destruct_tty_driver(struct kref
*kref
)
3202 struct tty_driver
*driver
= container_of(kref
, struct tty_driver
, kref
);
3204 struct ktermios
*tp
;
3206 if (driver
->flags
& TTY_DRIVER_INSTALLED
) {
3208 * Free the termios and termios_locked structures because
3209 * we don't want to get memory leaks when modular tty
3210 * drivers are removed from the kernel.
3212 for (i
= 0; i
< driver
->num
; i
++) {
3213 tp
= driver
->termios
[i
];
3215 driver
->termios
[i
] = NULL
;
3218 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
))
3219 tty_unregister_device(driver
, i
);
3221 proc_tty_unregister_driver(driver
);
3222 if (driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
)
3223 cdev_del(&driver
->cdevs
[0]);
3225 kfree(driver
->cdevs
);
3226 kfree(driver
->ports
);
3227 kfree(driver
->termios
);
3228 kfree(driver
->ttys
);
3232 void tty_driver_kref_put(struct tty_driver
*driver
)
3234 kref_put(&driver
->kref
, destruct_tty_driver
);
3236 EXPORT_SYMBOL(tty_driver_kref_put
);
3238 void tty_set_operations(struct tty_driver
*driver
,
3239 const struct tty_operations
*op
)
3243 EXPORT_SYMBOL(tty_set_operations
);
3245 void put_tty_driver(struct tty_driver
*d
)
3247 tty_driver_kref_put(d
);
3249 EXPORT_SYMBOL(put_tty_driver
);
3252 * Called by a tty driver to register itself.
3254 int tty_register_driver(struct tty_driver
*driver
)
3261 if (!driver
->major
) {
3262 error
= alloc_chrdev_region(&dev
, driver
->minor_start
,
3263 driver
->num
, driver
->name
);
3265 driver
->major
= MAJOR(dev
);
3266 driver
->minor_start
= MINOR(dev
);
3269 dev
= MKDEV(driver
->major
, driver
->minor_start
);
3270 error
= register_chrdev_region(dev
, driver
->num
, driver
->name
);
3275 if (driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
) {
3276 error
= tty_cdev_add(driver
, dev
, 0, driver
->num
);
3278 goto err_unreg_char
;
3281 mutex_lock(&tty_mutex
);
3282 list_add(&driver
->tty_drivers
, &tty_drivers
);
3283 mutex_unlock(&tty_mutex
);
3285 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
)) {
3286 for (i
= 0; i
< driver
->num
; i
++) {
3287 d
= tty_register_device(driver
, i
, NULL
);
3290 goto err_unreg_devs
;
3294 proc_tty_register_driver(driver
);
3295 driver
->flags
|= TTY_DRIVER_INSTALLED
;
3299 for (i
--; i
>= 0; i
--)
3300 tty_unregister_device(driver
, i
);
3302 mutex_lock(&tty_mutex
);
3303 list_del(&driver
->tty_drivers
);
3304 mutex_unlock(&tty_mutex
);
3307 unregister_chrdev_region(dev
, driver
->num
);
3311 EXPORT_SYMBOL(tty_register_driver
);
3314 * Called by a tty driver to unregister itself.
3316 int tty_unregister_driver(struct tty_driver
*driver
)
3320 if (driver
->refcount
)
3323 unregister_chrdev_region(MKDEV(driver
->major
, driver
->minor_start
),
3325 mutex_lock(&tty_mutex
);
3326 list_del(&driver
->tty_drivers
);
3327 mutex_unlock(&tty_mutex
);
3331 EXPORT_SYMBOL(tty_unregister_driver
);
3333 dev_t
tty_devnum(struct tty_struct
*tty
)
3335 return MKDEV(tty
->driver
->major
, tty
->driver
->minor_start
) + tty
->index
;
3337 EXPORT_SYMBOL(tty_devnum
);
3339 void proc_clear_tty(struct task_struct
*p
)
3341 unsigned long flags
;
3342 struct tty_struct
*tty
;
3343 spin_lock_irqsave(&p
->sighand
->siglock
, flags
);
3344 tty
= p
->signal
->tty
;
3345 p
->signal
->tty
= NULL
;
3346 spin_unlock_irqrestore(&p
->sighand
->siglock
, flags
);
3350 /* Called under the sighand lock */
3352 static void __proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
)
3355 unsigned long flags
;
3356 /* We should not have a session or pgrp to put here but.... */
3357 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
3358 put_pid(tty
->session
);
3360 tty
->pgrp
= get_pid(task_pgrp(tsk
));
3361 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
3362 tty
->session
= get_pid(task_session(tsk
));
3363 if (tsk
->signal
->tty
) {
3364 printk(KERN_DEBUG
"tty not NULL!!\n");
3365 tty_kref_put(tsk
->signal
->tty
);
3368 put_pid(tsk
->signal
->tty_old_pgrp
);
3369 tsk
->signal
->tty
= tty_kref_get(tty
);
3370 tsk
->signal
->tty_old_pgrp
= NULL
;
3373 static void proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
)
3375 spin_lock_irq(&tsk
->sighand
->siglock
);
3376 __proc_set_tty(tsk
, tty
);
3377 spin_unlock_irq(&tsk
->sighand
->siglock
);
3380 struct tty_struct
*get_current_tty(void)
3382 struct tty_struct
*tty
;
3383 unsigned long flags
;
3385 spin_lock_irqsave(¤t
->sighand
->siglock
, flags
);
3386 tty
= tty_kref_get(current
->signal
->tty
);
3387 spin_unlock_irqrestore(¤t
->sighand
->siglock
, flags
);
3390 EXPORT_SYMBOL_GPL(get_current_tty
);
3392 void tty_default_fops(struct file_operations
*fops
)
3398 * Initialize the console device. This is called *early*, so
3399 * we can't necessarily depend on lots of kernel help here.
3400 * Just do some early initializations, and do the complex setup
3403 void __init
console_init(void)
3407 /* Setup the default TTY line discipline. */
3411 * set up the console device so that later boot sequences can
3412 * inform about problems etc..
3414 call
= __con_initcall_start
;
3415 while (call
< __con_initcall_end
) {
3421 static char *tty_devnode(struct device
*dev
, umode_t
*mode
)
3425 if (dev
->devt
== MKDEV(TTYAUX_MAJOR
, 0) ||
3426 dev
->devt
== MKDEV(TTYAUX_MAJOR
, 2))
3431 static int __init
tty_class_init(void)
3433 tty_class
= class_create(THIS_MODULE
, "tty");
3434 if (IS_ERR(tty_class
))
3435 return PTR_ERR(tty_class
);
3436 tty_class
->devnode
= tty_devnode
;
3440 postcore_initcall(tty_class_init
);
3442 /* 3/2004 jmc: why do these devices exist? */
3443 static struct cdev tty_cdev
, console_cdev
;
3445 static ssize_t
show_cons_active(struct device
*dev
,
3446 struct device_attribute
*attr
, char *buf
)
3448 struct console
*cs
[16];
3454 for_each_console(c
) {
3459 if ((c
->flags
& CON_ENABLED
) == 0)
3462 if (i
>= ARRAY_SIZE(cs
))
3466 count
+= sprintf(buf
+ count
, "%s%d%c",
3467 cs
[i
]->name
, cs
[i
]->index
, i
? ' ':'\n');
3472 static DEVICE_ATTR(active
, S_IRUGO
, show_cons_active
, NULL
);
3474 static struct device
*consdev
;
3476 void console_sysfs_notify(void)
3479 sysfs_notify(&consdev
->kobj
, NULL
, "active");
3483 * Ok, now we can initialize the rest of the tty devices and can count
3484 * on memory allocations, interrupts etc..
3486 int __init
tty_init(void)
3488 cdev_init(&tty_cdev
, &tty_fops
);
3489 if (cdev_add(&tty_cdev
, MKDEV(TTYAUX_MAJOR
, 0), 1) ||
3490 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 0), 1, "/dev/tty") < 0)
3491 panic("Couldn't register /dev/tty driver\n");
3492 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 0), NULL
, "tty");
3494 cdev_init(&console_cdev
, &console_fops
);
3495 if (cdev_add(&console_cdev
, MKDEV(TTYAUX_MAJOR
, 1), 1) ||
3496 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 1), 1, "/dev/console") < 0)
3497 panic("Couldn't register /dev/console driver\n");
3498 consdev
= device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 1), NULL
,
3500 if (IS_ERR(consdev
))
3503 WARN_ON(device_create_file(consdev
, &dev_attr_active
) < 0);
3506 vty_init(&console_fops
);