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 a "kworker" 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
);
984 void tty_write_unlock(struct tty_struct
*tty
)
985 __releases(&tty
->atomic_write_lock
)
987 mutex_unlock(&tty
->atomic_write_lock
);
988 wake_up_interruptible_poll(&tty
->write_wait
, POLLOUT
);
991 int tty_write_lock(struct tty_struct
*tty
, int ndelay
)
992 __acquires(&tty
->atomic_write_lock
)
994 if (!mutex_trylock(&tty
->atomic_write_lock
)) {
997 if (mutex_lock_interruptible(&tty
->atomic_write_lock
))
1004 * Split writes up in sane blocksizes to avoid
1005 * denial-of-service type attacks
1007 static inline ssize_t
do_tty_write(
1008 ssize_t (*write
)(struct tty_struct
*, struct file
*, const unsigned char *, size_t),
1009 struct tty_struct
*tty
,
1011 const char __user
*buf
,
1014 ssize_t ret
, written
= 0;
1017 ret
= tty_write_lock(tty
, file
->f_flags
& O_NDELAY
);
1022 * We chunk up writes into a temporary buffer. This
1023 * simplifies low-level drivers immensely, since they
1024 * don't have locking issues and user mode accesses.
1026 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1029 * The default chunk-size is 2kB, because the NTTY
1030 * layer has problems with bigger chunks. It will
1031 * claim to be able to handle more characters than
1034 * FIXME: This can probably go away now except that 64K chunks
1035 * are too likely to fail unless switched to vmalloc...
1038 if (test_bit(TTY_NO_WRITE_SPLIT
, &tty
->flags
))
1043 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1044 if (tty
->write_cnt
< chunk
) {
1045 unsigned char *buf_chunk
;
1050 buf_chunk
= kmalloc(chunk
, GFP_KERNEL
);
1055 kfree(tty
->write_buf
);
1056 tty
->write_cnt
= chunk
;
1057 tty
->write_buf
= buf_chunk
;
1060 /* Do the write .. */
1062 size_t size
= count
;
1066 if (copy_from_user(tty
->write_buf
, buf
, size
))
1068 ret
= write(tty
, file
, tty
->write_buf
, size
);
1077 if (signal_pending(current
))
1084 tty_write_unlock(tty
);
1089 * tty_write_message - write a message to a certain tty, not just the console.
1090 * @tty: the destination tty_struct
1091 * @msg: the message to write
1093 * This is used for messages that need to be redirected to a specific tty.
1094 * We don't put it into the syslog queue right now maybe in the future if
1097 * We must still hold the BTM and test the CLOSING flag for the moment.
1100 void tty_write_message(struct tty_struct
*tty
, char *msg
)
1103 mutex_lock(&tty
->atomic_write_lock
);
1105 if (tty
->ops
->write
&& !test_bit(TTY_CLOSING
, &tty
->flags
)) {
1107 tty
->ops
->write(tty
, msg
, strlen(msg
));
1110 tty_write_unlock(tty
);
1117 * tty_write - write method for tty device file
1118 * @file: tty file pointer
1119 * @buf: user data to write
1120 * @count: bytes to write
1123 * Write data to a tty device via the line discipline.
1126 * Locks the line discipline as required
1127 * Writes to the tty driver are serialized by the atomic_write_lock
1128 * and are then processed in chunks to the device. The line discipline
1129 * write method will not be invoked in parallel for each device.
1132 static ssize_t
tty_write(struct file
*file
, const char __user
*buf
,
1133 size_t count
, loff_t
*ppos
)
1135 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
1136 struct tty_struct
*tty
= file_tty(file
);
1137 struct tty_ldisc
*ld
;
1140 if (tty_paranoia_check(tty
, inode
, "tty_write"))
1142 if (!tty
|| !tty
->ops
->write
||
1143 (test_bit(TTY_IO_ERROR
, &tty
->flags
)))
1145 /* Short term debug to catch buggy drivers */
1146 if (tty
->ops
->write_room
== NULL
)
1147 printk(KERN_ERR
"tty driver %s lacks a write_room method.\n",
1149 ld
= tty_ldisc_ref_wait(tty
);
1150 if (!ld
->ops
->write
)
1153 ret
= do_tty_write(ld
->ops
->write
, tty
, file
, buf
, count
);
1154 tty_ldisc_deref(ld
);
1158 ssize_t
redirected_tty_write(struct file
*file
, const char __user
*buf
,
1159 size_t count
, loff_t
*ppos
)
1161 struct file
*p
= NULL
;
1163 spin_lock(&redirect_lock
);
1165 p
= get_file(redirect
);
1166 spin_unlock(&redirect_lock
);
1170 res
= vfs_write(p
, buf
, count
, &p
->f_pos
);
1174 return tty_write(file
, buf
, count
, ppos
);
1177 static char ptychar
[] = "pqrstuvwxyzabcde";
1180 * pty_line_name - generate name for a pty
1181 * @driver: the tty driver in use
1182 * @index: the minor number
1183 * @p: output buffer of at least 6 bytes
1185 * Generate a name from a driver reference and write it to the output
1190 static void pty_line_name(struct tty_driver
*driver
, int index
, char *p
)
1192 int i
= index
+ driver
->name_base
;
1193 /* ->name is initialized to "ttyp", but "tty" is expected */
1194 sprintf(p
, "%s%c%x",
1195 driver
->subtype
== PTY_TYPE_SLAVE
? "tty" : driver
->name
,
1196 ptychar
[i
>> 4 & 0xf], i
& 0xf);
1200 * tty_line_name - generate name for a tty
1201 * @driver: the tty driver in use
1202 * @index: the minor number
1203 * @p: output buffer of at least 7 bytes
1205 * Generate a name from a driver reference and write it to the output
1210 static void tty_line_name(struct tty_driver
*driver
, int index
, char *p
)
1212 if (driver
->flags
& TTY_DRIVER_UNNUMBERED_NODE
)
1213 strcpy(p
, driver
->name
);
1215 sprintf(p
, "%s%d", driver
->name
, index
+ driver
->name_base
);
1219 * tty_driver_lookup_tty() - find an existing tty, if any
1220 * @driver: the driver for the tty
1221 * @idx: the minor number
1223 * Return the tty, if found or ERR_PTR() otherwise.
1225 * Locking: tty_mutex must be held. If tty is found, the mutex must
1226 * be held until the 'fast-open' is also done. Will change once we
1227 * have refcounting in the driver and per driver locking
1229 static struct tty_struct
*tty_driver_lookup_tty(struct tty_driver
*driver
,
1230 struct inode
*inode
, int idx
)
1232 if (driver
->ops
->lookup
)
1233 return driver
->ops
->lookup(driver
, inode
, idx
);
1235 return driver
->ttys
[idx
];
1239 * tty_init_termios - helper for termios setup
1240 * @tty: the tty to set up
1242 * Initialise the termios structures for this tty. Thus runs under
1243 * the tty_mutex currently so we can be relaxed about ordering.
1246 int tty_init_termios(struct tty_struct
*tty
)
1248 struct ktermios
*tp
;
1249 int idx
= tty
->index
;
1251 if (tty
->driver
->flags
& TTY_DRIVER_RESET_TERMIOS
)
1252 tty
->termios
= tty
->driver
->init_termios
;
1254 /* Check for lazy saved data */
1255 tp
= tty
->driver
->termios
[idx
];
1259 tty
->termios
= tty
->driver
->init_termios
;
1261 /* Compatibility until drivers always set this */
1262 tty
->termios
.c_ispeed
= tty_termios_input_baud_rate(&tty
->termios
);
1263 tty
->termios
.c_ospeed
= tty_termios_baud_rate(&tty
->termios
);
1266 EXPORT_SYMBOL_GPL(tty_init_termios
);
1268 int tty_standard_install(struct tty_driver
*driver
, struct tty_struct
*tty
)
1270 int ret
= tty_init_termios(tty
);
1274 tty_driver_kref_get(driver
);
1276 driver
->ttys
[tty
->index
] = tty
;
1279 EXPORT_SYMBOL_GPL(tty_standard_install
);
1282 * tty_driver_install_tty() - install a tty entry in the driver
1283 * @driver: the driver for the tty
1286 * Install a tty object into the driver tables. The tty->index field
1287 * will be set by the time this is called. This method is responsible
1288 * for ensuring any need additional structures are allocated and
1291 * Locking: tty_mutex for now
1293 static int tty_driver_install_tty(struct tty_driver
*driver
,
1294 struct tty_struct
*tty
)
1296 return driver
->ops
->install
? driver
->ops
->install(driver
, tty
) :
1297 tty_standard_install(driver
, tty
);
1301 * tty_driver_remove_tty() - remove a tty from the driver tables
1302 * @driver: the driver for the tty
1303 * @idx: the minor number
1305 * Remvoe a tty object from the driver tables. The tty->index field
1306 * will be set by the time this is called.
1308 * Locking: tty_mutex for now
1310 void tty_driver_remove_tty(struct tty_driver
*driver
, struct tty_struct
*tty
)
1312 if (driver
->ops
->remove
)
1313 driver
->ops
->remove(driver
, tty
);
1315 driver
->ttys
[tty
->index
] = NULL
;
1319 * tty_reopen() - fast re-open of an open tty
1320 * @tty - the tty to open
1322 * Return 0 on success, -errno on error.
1324 * Locking: tty_mutex must be held from the time the tty was found
1325 * till this open completes.
1327 static int tty_reopen(struct tty_struct
*tty
)
1329 struct tty_driver
*driver
= tty
->driver
;
1331 if (test_bit(TTY_CLOSING
, &tty
->flags
) ||
1332 test_bit(TTY_HUPPING
, &tty
->flags
) ||
1333 test_bit(TTY_LDISC_CHANGING
, &tty
->flags
))
1336 if (driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1337 driver
->subtype
== PTY_TYPE_MASTER
) {
1339 * special case for PTY masters: only one open permitted,
1340 * and the slave side open count is incremented as well.
1349 mutex_lock(&tty
->ldisc_mutex
);
1350 WARN_ON(!test_bit(TTY_LDISC
, &tty
->flags
));
1351 mutex_unlock(&tty
->ldisc_mutex
);
1357 * tty_init_dev - initialise a tty device
1358 * @driver: tty driver we are opening a device on
1359 * @idx: device index
1360 * @ret_tty: returned tty structure
1362 * Prepare a tty device. This may not be a "new" clean device but
1363 * could also be an active device. The pty drivers require special
1364 * handling because of this.
1367 * The function is called under the tty_mutex, which
1368 * protects us from the tty struct or driver itself going away.
1370 * On exit the tty device has the line discipline attached and
1371 * a reference count of 1. If a pair was created for pty/tty use
1372 * and the other was a pty master then it too has a reference count of 1.
1374 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1375 * failed open. The new code protects the open with a mutex, so it's
1376 * really quite straightforward. The mutex locking can probably be
1377 * relaxed for the (most common) case of reopening a tty.
1380 struct tty_struct
*tty_init_dev(struct tty_driver
*driver
, int idx
)
1382 struct tty_struct
*tty
;
1386 * First time open is complex, especially for PTY devices.
1387 * This code guarantees that either everything succeeds and the
1388 * TTY is ready for operation, or else the table slots are vacated
1389 * and the allocated memory released. (Except that the termios
1390 * and locked termios may be retained.)
1393 if (!try_module_get(driver
->owner
))
1394 return ERR_PTR(-ENODEV
);
1396 tty
= alloc_tty_struct();
1399 goto err_module_put
;
1401 initialize_tty_struct(tty
, driver
, idx
);
1404 retval
= tty_driver_install_tty(driver
, tty
);
1406 goto err_deinit_tty
;
1409 tty
->port
= driver
->ports
[idx
];
1411 WARN_RATELIMIT(!tty
->port
,
1412 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1413 __func__
, tty
->driver
->name
);
1415 tty
->port
->itty
= tty
;
1418 * Structures all installed ... call the ldisc open routines.
1419 * If we fail here just call release_tty to clean up. No need
1420 * to decrement the use counts, as release_tty doesn't care.
1422 retval
= tty_ldisc_setup(tty
, tty
->link
);
1424 goto err_release_tty
;
1425 /* Return the tty locked so that it cannot vanish under the caller */
1430 deinitialize_tty_struct(tty
);
1431 free_tty_struct(tty
);
1433 module_put(driver
->owner
);
1434 return ERR_PTR(retval
);
1436 /* call the tty release_tty routine to clean out this slot */
1439 printk_ratelimited(KERN_INFO
"tty_init_dev: ldisc open failed, "
1440 "clearing slot %d\n", idx
);
1441 release_tty(tty
, idx
);
1442 return ERR_PTR(retval
);
1445 void tty_free_termios(struct tty_struct
*tty
)
1447 struct ktermios
*tp
;
1448 int idx
= tty
->index
;
1450 /* If the port is going to reset then it has no termios to save */
1451 if (tty
->driver
->flags
& TTY_DRIVER_RESET_TERMIOS
)
1454 /* Stash the termios data */
1455 tp
= tty
->driver
->termios
[idx
];
1457 tp
= kmalloc(sizeof(struct ktermios
), GFP_KERNEL
);
1459 pr_warn("tty: no memory to save termios state.\n");
1462 tty
->driver
->termios
[idx
] = tp
;
1466 EXPORT_SYMBOL(tty_free_termios
);
1470 * release_one_tty - release tty structure memory
1471 * @kref: kref of tty we are obliterating
1473 * Releases memory associated with a tty structure, and clears out the
1474 * driver table slots. This function is called when a device is no longer
1475 * in use. It also gets called when setup of a device fails.
1478 * takes the file list lock internally when working on the list
1479 * of ttys that the driver keeps.
1481 * This method gets called from a work queue so that the driver private
1482 * cleanup ops can sleep (needed for USB at least)
1484 static void release_one_tty(struct work_struct
*work
)
1486 struct tty_struct
*tty
=
1487 container_of(work
, struct tty_struct
, hangup_work
);
1488 struct tty_driver
*driver
= tty
->driver
;
1490 if (tty
->ops
->cleanup
)
1491 tty
->ops
->cleanup(tty
);
1494 tty_driver_kref_put(driver
);
1495 module_put(driver
->owner
);
1497 spin_lock(&tty_files_lock
);
1498 list_del_init(&tty
->tty_files
);
1499 spin_unlock(&tty_files_lock
);
1502 put_pid(tty
->session
);
1503 free_tty_struct(tty
);
1506 static void queue_release_one_tty(struct kref
*kref
)
1508 struct tty_struct
*tty
= container_of(kref
, struct tty_struct
, kref
);
1510 /* The hangup queue is now free so we can reuse it rather than
1511 waste a chunk of memory for each port */
1512 INIT_WORK(&tty
->hangup_work
, release_one_tty
);
1513 schedule_work(&tty
->hangup_work
);
1517 * tty_kref_put - release a tty kref
1520 * Release a reference to a tty device and if need be let the kref
1521 * layer destruct the object for us
1524 void tty_kref_put(struct tty_struct
*tty
)
1527 kref_put(&tty
->kref
, queue_release_one_tty
);
1529 EXPORT_SYMBOL(tty_kref_put
);
1532 * release_tty - release tty structure memory
1534 * Release both @tty and a possible linked partner (think pty pair),
1535 * and decrement the refcount of the backing module.
1539 * takes the file list lock internally when working on the list
1540 * of ttys that the driver keeps.
1543 static void release_tty(struct tty_struct
*tty
, int idx
)
1545 /* This should always be true but check for the moment */
1546 WARN_ON(tty
->index
!= idx
);
1547 WARN_ON(!mutex_is_locked(&tty_mutex
));
1548 if (tty
->ops
->shutdown
)
1549 tty
->ops
->shutdown(tty
);
1550 tty_free_termios(tty
);
1551 tty_driver_remove_tty(tty
->driver
, tty
);
1552 tty
->port
->itty
= NULL
;
1555 tty_kref_put(tty
->link
);
1560 * tty_release_checks - check a tty before real release
1561 * @tty: tty to check
1562 * @o_tty: link of @tty (if any)
1563 * @idx: index of the tty
1565 * Performs some paranoid checking before true release of the @tty.
1566 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1568 static int tty_release_checks(struct tty_struct
*tty
, struct tty_struct
*o_tty
,
1571 #ifdef TTY_PARANOIA_CHECK
1572 if (idx
< 0 || idx
>= tty
->driver
->num
) {
1573 printk(KERN_DEBUG
"%s: bad idx when trying to free (%s)\n",
1574 __func__
, tty
->name
);
1578 /* not much to check for devpts */
1579 if (tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
)
1582 if (tty
!= tty
->driver
->ttys
[idx
]) {
1583 printk(KERN_DEBUG
"%s: driver.table[%d] not tty for (%s)\n",
1584 __func__
, idx
, tty
->name
);
1587 if (tty
->driver
->other
) {
1588 if (o_tty
!= tty
->driver
->other
->ttys
[idx
]) {
1589 printk(KERN_DEBUG
"%s: other->table[%d] not o_tty for (%s)\n",
1590 __func__
, idx
, tty
->name
);
1593 if (o_tty
->link
!= tty
) {
1594 printk(KERN_DEBUG
"%s: bad pty pointers\n", __func__
);
1603 * tty_release - vfs callback for close
1604 * @inode: inode of tty
1605 * @filp: file pointer for handle to tty
1607 * Called the last time each file handle is closed that references
1608 * this tty. There may however be several such references.
1611 * Takes bkl. See tty_release_dev
1613 * Even releasing the tty structures is a tricky business.. We have
1614 * to be very careful that the structures are all released at the
1615 * same time, as interrupts might otherwise get the wrong pointers.
1617 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1618 * lead to double frees or releasing memory still in use.
1621 int tty_release(struct inode
*inode
, struct file
*filp
)
1623 struct tty_struct
*tty
= file_tty(filp
);
1624 struct tty_struct
*o_tty
;
1625 int pty_master
, tty_closing
, o_tty_closing
, do_sleep
;
1629 if (tty_paranoia_check(tty
, inode
, __func__
))
1633 check_tty_count(tty
, __func__
);
1635 __tty_fasync(-1, filp
, 0);
1638 pty_master
= (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1639 tty
->driver
->subtype
== PTY_TYPE_MASTER
);
1640 /* Review: parallel close */
1643 if (tty_release_checks(tty
, o_tty
, idx
)) {
1648 #ifdef TTY_DEBUG_HANGUP
1649 printk(KERN_DEBUG
"%s: %s (tty count=%d)...\n", __func__
,
1650 tty_name(tty
, buf
), tty
->count
);
1653 if (tty
->ops
->close
)
1654 tty
->ops
->close(tty
, filp
);
1658 * Sanity check: if tty->count is going to zero, there shouldn't be
1659 * any waiters on tty->read_wait or tty->write_wait. We test the
1660 * wait queues and kick everyone out _before_ actually starting to
1661 * close. This ensures that we won't block while releasing the tty
1664 * The test for the o_tty closing is necessary, since the master and
1665 * slave sides may close in any order. If the slave side closes out
1666 * first, its count will be one, since the master side holds an open.
1667 * Thus this test wouldn't be triggered at the time the slave closes,
1670 * Note that it's possible for the tty to be opened again while we're
1671 * flushing out waiters. By recalculating the closing flags before
1672 * each iteration we avoid any problems.
1675 /* Guard against races with tty->count changes elsewhere and
1676 opens on /dev/tty */
1678 mutex_lock(&tty_mutex
);
1679 tty_lock_pair(tty
, o_tty
);
1680 tty_closing
= tty
->count
<= 1;
1681 o_tty_closing
= o_tty
&&
1682 (o_tty
->count
<= (pty_master
? 1 : 0));
1686 if (waitqueue_active(&tty
->read_wait
)) {
1687 wake_up_poll(&tty
->read_wait
, POLLIN
);
1690 if (waitqueue_active(&tty
->write_wait
)) {
1691 wake_up_poll(&tty
->write_wait
, POLLOUT
);
1695 if (o_tty_closing
) {
1696 if (waitqueue_active(&o_tty
->read_wait
)) {
1697 wake_up_poll(&o_tty
->read_wait
, POLLIN
);
1700 if (waitqueue_active(&o_tty
->write_wait
)) {
1701 wake_up_poll(&o_tty
->write_wait
, POLLOUT
);
1708 printk(KERN_WARNING
"%s: %s: read/write wait queue active!\n",
1709 __func__
, tty_name(tty
, buf
));
1710 tty_unlock_pair(tty
, o_tty
);
1711 mutex_unlock(&tty_mutex
);
1716 * The closing flags are now consistent with the open counts on
1717 * both sides, and we've completed the last operation that could
1718 * block, so it's safe to proceed with closing.
1720 * We must *not* drop the tty_mutex until we ensure that a further
1721 * entry into tty_open can not pick up this tty.
1724 if (--o_tty
->count
< 0) {
1725 printk(KERN_WARNING
"%s: bad pty slave count (%d) for %s\n",
1726 __func__
, o_tty
->count
, tty_name(o_tty
, buf
));
1730 if (--tty
->count
< 0) {
1731 printk(KERN_WARNING
"%s: bad tty->count (%d) for %s\n",
1732 __func__
, tty
->count
, tty_name(tty
, buf
));
1737 * We've decremented tty->count, so we need to remove this file
1738 * descriptor off the tty->tty_files list; this serves two
1740 * - check_tty_count sees the correct number of file descriptors
1741 * associated with this tty.
1742 * - do_tty_hangup no longer sees this file descriptor as
1743 * something that needs to be handled for hangups.
1748 * Perform some housekeeping before deciding whether to return.
1750 * Set the TTY_CLOSING flag if this was the last open. In the
1751 * case of a pty we may have to wait around for the other side
1752 * to close, and TTY_CLOSING makes sure we can't be reopened.
1755 set_bit(TTY_CLOSING
, &tty
->flags
);
1757 set_bit(TTY_CLOSING
, &o_tty
->flags
);
1760 * If _either_ side is closing, make sure there aren't any
1761 * processes that still think tty or o_tty is their controlling
1764 if (tty_closing
|| o_tty_closing
) {
1765 read_lock(&tasklist_lock
);
1766 session_clear_tty(tty
->session
);
1768 session_clear_tty(o_tty
->session
);
1769 read_unlock(&tasklist_lock
);
1772 mutex_unlock(&tty_mutex
);
1773 tty_unlock_pair(tty
, o_tty
);
1774 /* At this point the TTY_CLOSING flag should ensure a dead tty
1775 cannot be re-opened by a racing opener */
1777 /* check whether both sides are closing ... */
1778 if (!tty_closing
|| (o_tty
&& !o_tty_closing
))
1781 #ifdef TTY_DEBUG_HANGUP
1782 printk(KERN_DEBUG
"%s: freeing tty structure...\n", __func__
);
1785 * Ask the line discipline code to release its structures
1787 tty_ldisc_release(tty
, o_tty
);
1789 * The release_tty function takes care of the details of clearing
1790 * the slots and preserving the termios structure. The tty_unlock_pair
1791 * should be safe as we keep a kref while the tty is locked (so the
1792 * unlock never unlocks a freed tty).
1794 mutex_lock(&tty_mutex
);
1795 release_tty(tty
, idx
);
1796 mutex_unlock(&tty_mutex
);
1802 * tty_open_current_tty - get tty of current task for open
1803 * @device: device number
1804 * @filp: file pointer to tty
1805 * @return: tty of the current task iff @device is /dev/tty
1807 * We cannot return driver and index like for the other nodes because
1808 * devpts will not work then. It expects inodes to be from devpts FS.
1810 * We need to move to returning a refcounted object from all the lookup
1811 * paths including this one.
1813 static struct tty_struct
*tty_open_current_tty(dev_t device
, struct file
*filp
)
1815 struct tty_struct
*tty
;
1817 if (device
!= MKDEV(TTYAUX_MAJOR
, 0))
1820 tty
= get_current_tty();
1822 return ERR_PTR(-ENXIO
);
1824 filp
->f_flags
|= O_NONBLOCK
; /* Don't let /dev/tty block */
1827 /* FIXME: we put a reference and return a TTY! */
1828 /* This is only safe because the caller holds tty_mutex */
1833 * tty_lookup_driver - lookup a tty driver for a given device file
1834 * @device: device number
1835 * @filp: file pointer to tty
1836 * @noctty: set if the device should not become a controlling tty
1837 * @index: index for the device in the @return driver
1838 * @return: driver for this inode (with increased refcount)
1840 * If @return is not erroneous, the caller is responsible to decrement the
1841 * refcount by tty_driver_kref_put.
1843 * Locking: tty_mutex protects get_tty_driver
1845 static struct tty_driver
*tty_lookup_driver(dev_t device
, struct file
*filp
,
1846 int *noctty
, int *index
)
1848 struct tty_driver
*driver
;
1852 case MKDEV(TTY_MAJOR
, 0): {
1853 extern struct tty_driver
*console_driver
;
1854 driver
= tty_driver_kref_get(console_driver
);
1855 *index
= fg_console
;
1860 case MKDEV(TTYAUX_MAJOR
, 1): {
1861 struct tty_driver
*console_driver
= console_device(index
);
1862 if (console_driver
) {
1863 driver
= tty_driver_kref_get(console_driver
);
1865 /* Don't let /dev/console block */
1866 filp
->f_flags
|= O_NONBLOCK
;
1871 return ERR_PTR(-ENODEV
);
1874 driver
= get_tty_driver(device
, index
);
1876 return ERR_PTR(-ENODEV
);
1883 * tty_open - open a tty device
1884 * @inode: inode of device file
1885 * @filp: file pointer to tty
1887 * tty_open and tty_release keep up the tty count that contains the
1888 * number of opens done on a tty. We cannot use the inode-count, as
1889 * different inodes might point to the same tty.
1891 * Open-counting is needed for pty masters, as well as for keeping
1892 * track of serial lines: DTR is dropped when the last close happens.
1893 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1895 * The termios state of a pty is reset on first open so that
1896 * settings don't persist across reuse.
1898 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
1899 * tty->count should protect the rest.
1900 * ->siglock protects ->signal/->sighand
1902 * Note: the tty_unlock/lock cases without a ref are only safe due to
1906 static int tty_open(struct inode
*inode
, struct file
*filp
)
1908 struct tty_struct
*tty
;
1910 struct tty_driver
*driver
= NULL
;
1912 dev_t device
= inode
->i_rdev
;
1913 unsigned saved_flags
= filp
->f_flags
;
1915 nonseekable_open(inode
, filp
);
1918 retval
= tty_alloc_file(filp
);
1922 noctty
= filp
->f_flags
& O_NOCTTY
;
1926 mutex_lock(&tty_mutex
);
1927 /* This is protected by the tty_mutex */
1928 tty
= tty_open_current_tty(device
, filp
);
1930 retval
= PTR_ERR(tty
);
1933 driver
= tty_lookup_driver(device
, filp
, &noctty
, &index
);
1934 if (IS_ERR(driver
)) {
1935 retval
= PTR_ERR(driver
);
1939 /* check whether we're reopening an existing tty */
1940 tty
= tty_driver_lookup_tty(driver
, inode
, index
);
1942 retval
= PTR_ERR(tty
);
1949 retval
= tty_reopen(tty
);
1952 tty
= ERR_PTR(retval
);
1954 } else /* Returns with the tty_lock held for now */
1955 tty
= tty_init_dev(driver
, index
);
1957 mutex_unlock(&tty_mutex
);
1959 tty_driver_kref_put(driver
);
1961 retval
= PTR_ERR(tty
);
1965 tty_add_file(tty
, filp
);
1967 check_tty_count(tty
, __func__
);
1968 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1969 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
1971 #ifdef TTY_DEBUG_HANGUP
1972 printk(KERN_DEBUG
"%s: opening %s...\n", __func__
, tty
->name
);
1975 retval
= tty
->ops
->open(tty
, filp
);
1978 filp
->f_flags
= saved_flags
;
1980 if (!retval
&& test_bit(TTY_EXCLUSIVE
, &tty
->flags
) &&
1981 !capable(CAP_SYS_ADMIN
))
1985 #ifdef TTY_DEBUG_HANGUP
1986 printk(KERN_DEBUG
"%s: error %d in opening %s...\n", __func__
,
1989 tty_unlock(tty
); /* need to call tty_release without BTM */
1990 tty_release(inode
, filp
);
1991 if (retval
!= -ERESTARTSYS
)
1994 if (signal_pending(current
))
1999 * Need to reset f_op in case a hangup happened.
2001 if (filp
->f_op
== &hung_up_tty_fops
)
2002 filp
->f_op
= &tty_fops
;
2008 mutex_lock(&tty_mutex
);
2010 spin_lock_irq(¤t
->sighand
->siglock
);
2012 current
->signal
->leader
&&
2013 !current
->signal
->tty
&&
2014 tty
->session
== NULL
)
2015 __proc_set_tty(current
, tty
);
2016 spin_unlock_irq(¤t
->sighand
->siglock
);
2018 mutex_unlock(&tty_mutex
);
2021 mutex_unlock(&tty_mutex
);
2022 /* after locks to avoid deadlock */
2023 if (!IS_ERR_OR_NULL(driver
))
2024 tty_driver_kref_put(driver
);
2026 tty_free_file(filp
);
2033 * tty_poll - check tty status
2034 * @filp: file being polled
2035 * @wait: poll wait structures to update
2037 * Call the line discipline polling method to obtain the poll
2038 * status of the device.
2040 * Locking: locks called line discipline but ldisc poll method
2041 * may be re-entered freely by other callers.
2044 static unsigned int tty_poll(struct file
*filp
, poll_table
*wait
)
2046 struct tty_struct
*tty
= file_tty(filp
);
2047 struct tty_ldisc
*ld
;
2050 if (tty_paranoia_check(tty
, filp
->f_path
.dentry
->d_inode
, "tty_poll"))
2053 ld
= tty_ldisc_ref_wait(tty
);
2055 ret
= (ld
->ops
->poll
)(tty
, filp
, wait
);
2056 tty_ldisc_deref(ld
);
2060 static int __tty_fasync(int fd
, struct file
*filp
, int on
)
2062 struct tty_struct
*tty
= file_tty(filp
);
2063 unsigned long flags
;
2066 if (tty_paranoia_check(tty
, filp
->f_path
.dentry
->d_inode
, "tty_fasync"))
2069 retval
= fasync_helper(fd
, filp
, on
, &tty
->fasync
);
2076 if (!waitqueue_active(&tty
->read_wait
))
2077 tty
->minimum_to_wake
= 1;
2078 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2081 type
= PIDTYPE_PGID
;
2083 pid
= task_pid(current
);
2087 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2088 retval
= __f_setown(filp
, pid
, type
, 0);
2093 if (!tty
->fasync
&& !waitqueue_active(&tty
->read_wait
))
2094 tty
->minimum_to_wake
= N_TTY_BUF_SIZE
;
2101 static int tty_fasync(int fd
, struct file
*filp
, int on
)
2103 struct tty_struct
*tty
= file_tty(filp
);
2107 retval
= __tty_fasync(fd
, filp
, on
);
2114 * tiocsti - fake input character
2115 * @tty: tty to fake input into
2116 * @p: pointer to character
2118 * Fake input to a tty device. Does the necessary locking and
2121 * FIXME: does not honour flow control ??
2124 * Called functions take tty_ldisc_lock
2125 * current->signal->tty check is safe without locks
2127 * FIXME: may race normal receive processing
2130 static int tiocsti(struct tty_struct
*tty
, char __user
*p
)
2133 struct tty_ldisc
*ld
;
2135 if ((current
->signal
->tty
!= tty
) && !capable(CAP_SYS_ADMIN
))
2137 if (get_user(ch
, p
))
2139 tty_audit_tiocsti(tty
, ch
);
2140 ld
= tty_ldisc_ref_wait(tty
);
2141 ld
->ops
->receive_buf(tty
, &ch
, &mbz
, 1);
2142 tty_ldisc_deref(ld
);
2147 * tiocgwinsz - implement window query ioctl
2149 * @arg: user buffer for result
2151 * Copies the kernel idea of the window size into the user buffer.
2153 * Locking: tty->termios_mutex is taken to ensure the winsize data
2157 static int tiocgwinsz(struct tty_struct
*tty
, struct winsize __user
*arg
)
2161 mutex_lock(&tty
->termios_mutex
);
2162 err
= copy_to_user(arg
, &tty
->winsize
, sizeof(*arg
));
2163 mutex_unlock(&tty
->termios_mutex
);
2165 return err
? -EFAULT
: 0;
2169 * tty_do_resize - resize event
2170 * @tty: tty being resized
2171 * @rows: rows (character)
2172 * @cols: cols (character)
2174 * Update the termios variables and send the necessary signals to
2175 * peform a terminal resize correctly
2178 int tty_do_resize(struct tty_struct
*tty
, struct winsize
*ws
)
2181 unsigned long flags
;
2184 mutex_lock(&tty
->termios_mutex
);
2185 if (!memcmp(ws
, &tty
->winsize
, sizeof(*ws
)))
2187 /* Get the PID values and reference them so we can
2188 avoid holding the tty ctrl lock while sending signals */
2189 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2190 pgrp
= get_pid(tty
->pgrp
);
2191 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2194 kill_pgrp(pgrp
, SIGWINCH
, 1);
2199 mutex_unlock(&tty
->termios_mutex
);
2202 EXPORT_SYMBOL(tty_do_resize
);
2205 * tiocswinsz - implement window size set ioctl
2206 * @tty; tty side of tty
2207 * @arg: user buffer for result
2209 * Copies the user idea of the window size to the kernel. Traditionally
2210 * this is just advisory information but for the Linux console it
2211 * actually has driver level meaning and triggers a VC resize.
2214 * Driver dependent. The default do_resize method takes the
2215 * tty termios mutex and ctrl_lock. The console takes its own lock
2216 * then calls into the default method.
2219 static int tiocswinsz(struct tty_struct
*tty
, struct winsize __user
*arg
)
2221 struct winsize tmp_ws
;
2222 if (copy_from_user(&tmp_ws
, arg
, sizeof(*arg
)))
2225 if (tty
->ops
->resize
)
2226 return tty
->ops
->resize(tty
, &tmp_ws
);
2228 return tty_do_resize(tty
, &tmp_ws
);
2232 * tioccons - allow admin to move logical console
2233 * @file: the file to become console
2235 * Allow the administrator to move the redirected console device
2237 * Locking: uses redirect_lock to guard the redirect information
2240 static int tioccons(struct file
*file
)
2242 if (!capable(CAP_SYS_ADMIN
))
2244 if (file
->f_op
->write
== redirected_tty_write
) {
2246 spin_lock(&redirect_lock
);
2249 spin_unlock(&redirect_lock
);
2254 spin_lock(&redirect_lock
);
2256 spin_unlock(&redirect_lock
);
2259 redirect
= get_file(file
);
2260 spin_unlock(&redirect_lock
);
2265 * fionbio - non blocking ioctl
2266 * @file: file to set blocking value
2267 * @p: user parameter
2269 * Historical tty interfaces had a blocking control ioctl before
2270 * the generic functionality existed. This piece of history is preserved
2271 * in the expected tty API of posix OS's.
2273 * Locking: none, the open file handle ensures it won't go away.
2276 static int fionbio(struct file
*file
, int __user
*p
)
2280 if (get_user(nonblock
, p
))
2283 spin_lock(&file
->f_lock
);
2285 file
->f_flags
|= O_NONBLOCK
;
2287 file
->f_flags
&= ~O_NONBLOCK
;
2288 spin_unlock(&file
->f_lock
);
2293 * tiocsctty - set controlling tty
2294 * @tty: tty structure
2295 * @arg: user argument
2297 * This ioctl is used to manage job control. It permits a session
2298 * leader to set this tty as the controlling tty for the session.
2301 * Takes tty_mutex() to protect tty instance
2302 * Takes tasklist_lock internally to walk sessions
2303 * Takes ->siglock() when updating signal->tty
2306 static int tiocsctty(struct tty_struct
*tty
, int arg
)
2309 if (current
->signal
->leader
&& (task_session(current
) == tty
->session
))
2312 mutex_lock(&tty_mutex
);
2314 * The process must be a session leader and
2315 * not have a controlling tty already.
2317 if (!current
->signal
->leader
|| current
->signal
->tty
) {
2324 * This tty is already the controlling
2325 * tty for another session group!
2327 if (arg
== 1 && capable(CAP_SYS_ADMIN
)) {
2331 read_lock(&tasklist_lock
);
2332 session_clear_tty(tty
->session
);
2333 read_unlock(&tasklist_lock
);
2339 proc_set_tty(current
, tty
);
2341 mutex_unlock(&tty_mutex
);
2346 * tty_get_pgrp - return a ref counted pgrp pid
2349 * Returns a refcounted instance of the pid struct for the process
2350 * group controlling the tty.
2353 struct pid
*tty_get_pgrp(struct tty_struct
*tty
)
2355 unsigned long flags
;
2358 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2359 pgrp
= get_pid(tty
->pgrp
);
2360 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2364 EXPORT_SYMBOL_GPL(tty_get_pgrp
);
2367 * tiocgpgrp - get process group
2368 * @tty: tty passed by user
2369 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2372 * Obtain the process group of the tty. If there is no process group
2375 * Locking: none. Reference to current->signal->tty is safe.
2378 static int tiocgpgrp(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
2383 * (tty == real_tty) is a cheap way of
2384 * testing if the tty is NOT a master pty.
2386 if (tty
== real_tty
&& current
->signal
->tty
!= real_tty
)
2388 pid
= tty_get_pgrp(real_tty
);
2389 ret
= put_user(pid_vnr(pid
), p
);
2395 * tiocspgrp - attempt to set process group
2396 * @tty: tty passed by user
2397 * @real_tty: tty side device matching tty passed by user
2400 * Set the process group of the tty to the session passed. Only
2401 * permitted where the tty session is our session.
2403 * Locking: RCU, ctrl lock
2406 static int tiocspgrp(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
2410 int retval
= tty_check_change(real_tty
);
2411 unsigned long flags
;
2417 if (!current
->signal
->tty
||
2418 (current
->signal
->tty
!= real_tty
) ||
2419 (real_tty
->session
!= task_session(current
)))
2421 if (get_user(pgrp_nr
, p
))
2426 pgrp
= find_vpid(pgrp_nr
);
2431 if (session_of_pgrp(pgrp
) != task_session(current
))
2434 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2435 put_pid(real_tty
->pgrp
);
2436 real_tty
->pgrp
= get_pid(pgrp
);
2437 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2444 * tiocgsid - get session id
2445 * @tty: tty passed by user
2446 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2447 * @p: pointer to returned session id
2449 * Obtain the session id of the tty. If there is no session
2452 * Locking: none. Reference to current->signal->tty is safe.
2455 static int tiocgsid(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
2458 * (tty == real_tty) is a cheap way of
2459 * testing if the tty is NOT a master pty.
2461 if (tty
== real_tty
&& current
->signal
->tty
!= real_tty
)
2463 if (!real_tty
->session
)
2465 return put_user(pid_vnr(real_tty
->session
), p
);
2469 * tiocsetd - set line discipline
2471 * @p: pointer to user data
2473 * Set the line discipline according to user request.
2475 * Locking: see tty_set_ldisc, this function is just a helper
2478 static int tiocsetd(struct tty_struct
*tty
, int __user
*p
)
2483 if (get_user(ldisc
, p
))
2486 ret
= tty_set_ldisc(tty
, ldisc
);
2492 * send_break - performed time break
2493 * @tty: device to break on
2494 * @duration: timeout in mS
2496 * Perform a timed break on hardware that lacks its own driver level
2497 * timed break functionality.
2500 * atomic_write_lock serializes
2504 static int send_break(struct tty_struct
*tty
, unsigned int duration
)
2508 if (tty
->ops
->break_ctl
== NULL
)
2511 if (tty
->driver
->flags
& TTY_DRIVER_HARDWARE_BREAK
)
2512 retval
= tty
->ops
->break_ctl(tty
, duration
);
2514 /* Do the work ourselves */
2515 if (tty_write_lock(tty
, 0) < 0)
2517 retval
= tty
->ops
->break_ctl(tty
, -1);
2520 if (!signal_pending(current
))
2521 msleep_interruptible(duration
);
2522 retval
= tty
->ops
->break_ctl(tty
, 0);
2524 tty_write_unlock(tty
);
2525 if (signal_pending(current
))
2532 * tty_tiocmget - get modem status
2534 * @file: user file pointer
2535 * @p: pointer to result
2537 * Obtain the modem status bits from the tty driver if the feature
2538 * is supported. Return -EINVAL if it is not available.
2540 * Locking: none (up to the driver)
2543 static int tty_tiocmget(struct tty_struct
*tty
, int __user
*p
)
2545 int retval
= -EINVAL
;
2547 if (tty
->ops
->tiocmget
) {
2548 retval
= tty
->ops
->tiocmget(tty
);
2551 retval
= put_user(retval
, p
);
2557 * tty_tiocmset - set modem status
2559 * @cmd: command - clear bits, set bits or set all
2560 * @p: pointer to desired bits
2562 * Set the modem status bits from the tty driver if the feature
2563 * is supported. Return -EINVAL if it is not available.
2565 * Locking: none (up to the driver)
2568 static int tty_tiocmset(struct tty_struct
*tty
, unsigned int cmd
,
2572 unsigned int set
, clear
, val
;
2574 if (tty
->ops
->tiocmset
== NULL
)
2577 retval
= get_user(val
, p
);
2593 set
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
2594 clear
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
2595 return tty
->ops
->tiocmset(tty
, set
, clear
);
2598 static int tty_tiocgicount(struct tty_struct
*tty
, void __user
*arg
)
2600 int retval
= -EINVAL
;
2601 struct serial_icounter_struct icount
;
2602 memset(&icount
, 0, sizeof(icount
));
2603 if (tty
->ops
->get_icount
)
2604 retval
= tty
->ops
->get_icount(tty
, &icount
);
2607 if (copy_to_user(arg
, &icount
, sizeof(icount
)))
2612 struct tty_struct
*tty_pair_get_tty(struct tty_struct
*tty
)
2614 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2615 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
2619 EXPORT_SYMBOL(tty_pair_get_tty
);
2621 struct tty_struct
*tty_pair_get_pty(struct tty_struct
*tty
)
2623 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2624 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
2628 EXPORT_SYMBOL(tty_pair_get_pty
);
2631 * Split this up, as gcc can choke on it otherwise..
2633 long tty_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
2635 struct tty_struct
*tty
= file_tty(file
);
2636 struct tty_struct
*real_tty
;
2637 void __user
*p
= (void __user
*)arg
;
2639 struct tty_ldisc
*ld
;
2640 struct inode
*inode
= file
->f_dentry
->d_inode
;
2642 if (tty_paranoia_check(tty
, inode
, "tty_ioctl"))
2645 real_tty
= tty_pair_get_tty(tty
);
2648 * Factor out some common prep work
2656 retval
= tty_check_change(tty
);
2659 if (cmd
!= TIOCCBRK
) {
2660 tty_wait_until_sent(tty
, 0);
2661 if (signal_pending(current
))
2672 return tiocsti(tty
, p
);
2674 return tiocgwinsz(real_tty
, p
);
2676 return tiocswinsz(real_tty
, p
);
2678 return real_tty
!= tty
? -EINVAL
: tioccons(file
);
2680 return fionbio(file
, p
);
2682 set_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2685 clear_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2689 int excl
= test_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2690 return put_user(excl
, (int __user
*)p
);
2693 if (current
->signal
->tty
!= tty
)
2698 return tiocsctty(tty
, arg
);
2700 return tiocgpgrp(tty
, real_tty
, p
);
2702 return tiocspgrp(tty
, real_tty
, p
);
2704 return tiocgsid(tty
, real_tty
, p
);
2706 return put_user(tty
->ldisc
->ops
->num
, (int __user
*)p
);
2708 return tiocsetd(tty
, p
);
2710 if (!capable(CAP_SYS_ADMIN
))
2716 unsigned int ret
= new_encode_dev(tty_devnum(real_tty
));
2717 return put_user(ret
, (unsigned int __user
*)p
);
2722 case TIOCSBRK
: /* Turn break on, unconditionally */
2723 if (tty
->ops
->break_ctl
)
2724 return tty
->ops
->break_ctl(tty
, -1);
2726 case TIOCCBRK
: /* Turn break off, unconditionally */
2727 if (tty
->ops
->break_ctl
)
2728 return tty
->ops
->break_ctl(tty
, 0);
2730 case TCSBRK
: /* SVID version: non-zero arg --> no break */
2731 /* non-zero arg means wait for all output data
2732 * to be sent (performed above) but don't send break.
2733 * This is used by the tcdrain() termios function.
2736 return send_break(tty
, 250);
2738 case TCSBRKP
: /* support for POSIX tcsendbreak() */
2739 return send_break(tty
, arg
? arg
*100 : 250);
2742 return tty_tiocmget(tty
, p
);
2746 return tty_tiocmset(tty
, cmd
, p
);
2748 retval
= tty_tiocgicount(tty
, p
);
2749 /* For the moment allow fall through to the old method */
2750 if (retval
!= -EINVAL
)
2757 /* flush tty buffer and allow ldisc to process ioctl */
2758 tty_buffer_flush(tty
);
2763 if (tty
->ops
->ioctl
) {
2764 retval
= (tty
->ops
->ioctl
)(tty
, cmd
, arg
);
2765 if (retval
!= -ENOIOCTLCMD
)
2768 ld
= tty_ldisc_ref_wait(tty
);
2770 if (ld
->ops
->ioctl
) {
2771 retval
= ld
->ops
->ioctl(tty
, file
, cmd
, arg
);
2772 if (retval
== -ENOIOCTLCMD
)
2775 tty_ldisc_deref(ld
);
2779 #ifdef CONFIG_COMPAT
2780 static long tty_compat_ioctl(struct file
*file
, unsigned int cmd
,
2783 struct inode
*inode
= file
->f_dentry
->d_inode
;
2784 struct tty_struct
*tty
= file_tty(file
);
2785 struct tty_ldisc
*ld
;
2786 int retval
= -ENOIOCTLCMD
;
2788 if (tty_paranoia_check(tty
, inode
, "tty_ioctl"))
2791 if (tty
->ops
->compat_ioctl
) {
2792 retval
= (tty
->ops
->compat_ioctl
)(tty
, cmd
, arg
);
2793 if (retval
!= -ENOIOCTLCMD
)
2797 ld
= tty_ldisc_ref_wait(tty
);
2798 if (ld
->ops
->compat_ioctl
)
2799 retval
= ld
->ops
->compat_ioctl(tty
, file
, cmd
, arg
);
2801 retval
= n_tty_compat_ioctl_helper(tty
, file
, cmd
, arg
);
2802 tty_ldisc_deref(ld
);
2808 static int this_tty(const void *t
, struct file
*file
, unsigned fd
)
2810 if (likely(file
->f_op
->read
!= tty_read
))
2812 return file_tty(file
) != t
? 0 : fd
+ 1;
2816 * This implements the "Secure Attention Key" --- the idea is to
2817 * prevent trojan horses by killing all processes associated with this
2818 * tty when the user hits the "Secure Attention Key". Required for
2819 * super-paranoid applications --- see the Orange Book for more details.
2821 * This code could be nicer; ideally it should send a HUP, wait a few
2822 * seconds, then send a INT, and then a KILL signal. But you then
2823 * have to coordinate with the init process, since all processes associated
2824 * with the current tty must be dead before the new getty is allowed
2827 * Now, if it would be correct ;-/ The current code has a nasty hole -
2828 * it doesn't catch files in flight. We may send the descriptor to ourselves
2829 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2831 * Nasty bug: do_SAK is being called in interrupt context. This can
2832 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2834 void __do_SAK(struct tty_struct
*tty
)
2839 struct task_struct
*g
, *p
;
2840 struct pid
*session
;
2845 session
= tty
->session
;
2847 tty_ldisc_flush(tty
);
2849 tty_driver_flush_buffer(tty
);
2851 read_lock(&tasklist_lock
);
2852 /* Kill the entire session */
2853 do_each_pid_task(session
, PIDTYPE_SID
, p
) {
2854 printk(KERN_NOTICE
"SAK: killed process %d"
2855 " (%s): task_session(p)==tty->session\n",
2856 task_pid_nr(p
), p
->comm
);
2857 send_sig(SIGKILL
, p
, 1);
2858 } while_each_pid_task(session
, PIDTYPE_SID
, p
);
2859 /* Now kill any processes that happen to have the
2862 do_each_thread(g
, p
) {
2863 if (p
->signal
->tty
== tty
) {
2864 printk(KERN_NOTICE
"SAK: killed process %d"
2865 " (%s): task_session(p)==tty->session\n",
2866 task_pid_nr(p
), p
->comm
);
2867 send_sig(SIGKILL
, p
, 1);
2871 i
= iterate_fd(p
->files
, 0, this_tty
, tty
);
2873 printk(KERN_NOTICE
"SAK: killed process %d"
2874 " (%s): fd#%d opened to the tty\n",
2875 task_pid_nr(p
), p
->comm
, i
- 1);
2876 force_sig(SIGKILL
, p
);
2879 } while_each_thread(g
, p
);
2880 read_unlock(&tasklist_lock
);
2884 static void do_SAK_work(struct work_struct
*work
)
2886 struct tty_struct
*tty
=
2887 container_of(work
, struct tty_struct
, SAK_work
);
2892 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2893 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2894 * the values which we write to it will be identical to the values which it
2895 * already has. --akpm
2897 void do_SAK(struct tty_struct
*tty
)
2901 schedule_work(&tty
->SAK_work
);
2904 EXPORT_SYMBOL(do_SAK
);
2906 static int dev_match_devt(struct device
*dev
, const void *data
)
2908 const dev_t
*devt
= data
;
2909 return dev
->devt
== *devt
;
2912 /* Must put_device() after it's unused! */
2913 static struct device
*tty_get_device(struct tty_struct
*tty
)
2915 dev_t devt
= tty_devnum(tty
);
2916 return class_find_device(tty_class
, NULL
, &devt
, dev_match_devt
);
2921 * initialize_tty_struct
2922 * @tty: tty to initialize
2924 * This subroutine initializes a tty structure that has been newly
2927 * Locking: none - tty in question must not be exposed at this point
2930 void initialize_tty_struct(struct tty_struct
*tty
,
2931 struct tty_driver
*driver
, int idx
)
2933 memset(tty
, 0, sizeof(struct tty_struct
));
2934 kref_init(&tty
->kref
);
2935 tty
->magic
= TTY_MAGIC
;
2936 tty_ldisc_init(tty
);
2937 tty
->session
= NULL
;
2939 mutex_init(&tty
->legacy_mutex
);
2940 mutex_init(&tty
->termios_mutex
);
2941 mutex_init(&tty
->ldisc_mutex
);
2942 init_waitqueue_head(&tty
->write_wait
);
2943 init_waitqueue_head(&tty
->read_wait
);
2944 INIT_WORK(&tty
->hangup_work
, do_tty_hangup
);
2945 mutex_init(&tty
->atomic_write_lock
);
2946 spin_lock_init(&tty
->ctrl_lock
);
2947 INIT_LIST_HEAD(&tty
->tty_files
);
2948 INIT_WORK(&tty
->SAK_work
, do_SAK_work
);
2950 tty
->driver
= driver
;
2951 tty
->ops
= driver
->ops
;
2953 tty_line_name(driver
, idx
, tty
->name
);
2954 tty
->dev
= tty_get_device(tty
);
2958 * deinitialize_tty_struct
2959 * @tty: tty to deinitialize
2961 * This subroutine deinitializes a tty structure that has been newly
2962 * allocated but tty_release cannot be called on that yet.
2964 * Locking: none - tty in question must not be exposed at this point
2966 void deinitialize_tty_struct(struct tty_struct
*tty
)
2968 tty_ldisc_deinit(tty
);
2972 * tty_put_char - write one character to a tty
2976 * Write one byte to the tty using the provided put_char method
2977 * if present. Returns the number of characters successfully output.
2979 * Note: the specific put_char operation in the driver layer may go
2980 * away soon. Don't call it directly, use this method
2983 int tty_put_char(struct tty_struct
*tty
, unsigned char ch
)
2985 if (tty
->ops
->put_char
)
2986 return tty
->ops
->put_char(tty
, ch
);
2987 return tty
->ops
->write(tty
, &ch
, 1);
2989 EXPORT_SYMBOL_GPL(tty_put_char
);
2991 struct class *tty_class
;
2993 static int tty_cdev_add(struct tty_driver
*driver
, dev_t dev
,
2994 unsigned int index
, unsigned int count
)
2996 /* init here, since reused cdevs cause crashes */
2997 cdev_init(&driver
->cdevs
[index
], &tty_fops
);
2998 driver
->cdevs
[index
].owner
= driver
->owner
;
2999 return cdev_add(&driver
->cdevs
[index
], dev
, count
);
3003 * tty_register_device - register a tty device
3004 * @driver: the tty driver that describes the tty device
3005 * @index: the index in the tty driver for this tty device
3006 * @device: a struct device that is associated with this tty device.
3007 * This field is optional, if there is no known struct device
3008 * for this tty device it can be set to NULL safely.
3010 * Returns a pointer to the struct device for this tty device
3011 * (or ERR_PTR(-EFOO) on error).
3013 * This call is required to be made to register an individual tty device
3014 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3015 * that bit is not set, this function should not be called by a tty
3021 struct device
*tty_register_device(struct tty_driver
*driver
, unsigned index
,
3022 struct device
*device
)
3024 return tty_register_device_attr(driver
, index
, device
, NULL
, NULL
);
3026 EXPORT_SYMBOL(tty_register_device
);
3028 static void tty_device_create_release(struct device
*dev
)
3030 pr_debug("device: '%s': %s\n", dev_name(dev
), __func__
);
3035 * tty_register_device_attr - register a tty device
3036 * @driver: the tty driver that describes the tty device
3037 * @index: the index in the tty driver for this tty device
3038 * @device: a struct device that is associated with this tty device.
3039 * This field is optional, if there is no known struct device
3040 * for this tty device it can be set to NULL safely.
3041 * @drvdata: Driver data to be set to device.
3042 * @attr_grp: Attribute group to be set on device.
3044 * Returns a pointer to the struct device for this tty device
3045 * (or ERR_PTR(-EFOO) on error).
3047 * This call is required to be made to register an individual tty device
3048 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3049 * that bit is not set, this function should not be called by a tty
3054 struct device
*tty_register_device_attr(struct tty_driver
*driver
,
3055 unsigned index
, struct device
*device
,
3057 const struct attribute_group
**attr_grp
)
3060 dev_t devt
= MKDEV(driver
->major
, driver
->minor_start
) + index
;
3061 struct device
*dev
= NULL
;
3062 int retval
= -ENODEV
;
3065 if (index
>= driver
->num
) {
3066 printk(KERN_ERR
"Attempt to register invalid tty line number "
3068 return ERR_PTR(-EINVAL
);
3071 if (driver
->type
== TTY_DRIVER_TYPE_PTY
)
3072 pty_line_name(driver
, index
, name
);
3074 tty_line_name(driver
, index
, name
);
3076 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
)) {
3077 retval
= tty_cdev_add(driver
, devt
, index
, 1);
3083 dev
= kzalloc(sizeof(*dev
), GFP_KERNEL
);
3090 dev
->class = tty_class
;
3091 dev
->parent
= device
;
3092 dev
->release
= tty_device_create_release
;
3093 dev_set_name(dev
, "%s", name
);
3094 dev
->groups
= attr_grp
;
3095 dev_set_drvdata(dev
, drvdata
);
3097 retval
= device_register(dev
);
3106 cdev_del(&driver
->cdevs
[index
]);
3107 return ERR_PTR(retval
);
3109 EXPORT_SYMBOL_GPL(tty_register_device_attr
);
3112 * tty_unregister_device - unregister a tty device
3113 * @driver: the tty driver that describes the tty device
3114 * @index: the index in the tty driver for this tty device
3116 * If a tty device is registered with a call to tty_register_device() then
3117 * this function must be called when the tty device is gone.
3122 void tty_unregister_device(struct tty_driver
*driver
, unsigned index
)
3124 device_destroy(tty_class
,
3125 MKDEV(driver
->major
, driver
->minor_start
) + index
);
3126 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
))
3127 cdev_del(&driver
->cdevs
[index
]);
3129 EXPORT_SYMBOL(tty_unregister_device
);
3132 * __tty_alloc_driver -- allocate tty driver
3133 * @lines: count of lines this driver can handle at most
3134 * @owner: module which is repsonsible for this driver
3135 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3137 * This should not be called directly, some of the provided macros should be
3138 * used instead. Use IS_ERR and friends on @retval.
3140 struct tty_driver
*__tty_alloc_driver(unsigned int lines
, struct module
*owner
,
3141 unsigned long flags
)
3143 struct tty_driver
*driver
;
3144 unsigned int cdevs
= 1;
3147 if (!lines
|| (flags
& TTY_DRIVER_UNNUMBERED_NODE
&& lines
> 1))
3148 return ERR_PTR(-EINVAL
);
3150 driver
= kzalloc(sizeof(struct tty_driver
), GFP_KERNEL
);
3152 return ERR_PTR(-ENOMEM
);
3154 kref_init(&driver
->kref
);
3155 driver
->magic
= TTY_DRIVER_MAGIC
;
3156 driver
->num
= lines
;
3157 driver
->owner
= owner
;
3158 driver
->flags
= flags
;
3160 if (!(flags
& TTY_DRIVER_DEVPTS_MEM
)) {
3161 driver
->ttys
= kcalloc(lines
, sizeof(*driver
->ttys
),
3163 driver
->termios
= kcalloc(lines
, sizeof(*driver
->termios
),
3165 if (!driver
->ttys
|| !driver
->termios
) {
3171 if (!(flags
& TTY_DRIVER_DYNAMIC_ALLOC
)) {
3172 driver
->ports
= kcalloc(lines
, sizeof(*driver
->ports
),
3174 if (!driver
->ports
) {
3181 driver
->cdevs
= kcalloc(cdevs
, sizeof(*driver
->cdevs
), GFP_KERNEL
);
3182 if (!driver
->cdevs
) {
3189 kfree(driver
->ports
);
3190 kfree(driver
->ttys
);
3191 kfree(driver
->termios
);
3193 return ERR_PTR(err
);
3195 EXPORT_SYMBOL(__tty_alloc_driver
);
3197 static void destruct_tty_driver(struct kref
*kref
)
3199 struct tty_driver
*driver
= container_of(kref
, struct tty_driver
, kref
);
3201 struct ktermios
*tp
;
3203 if (driver
->flags
& TTY_DRIVER_INSTALLED
) {
3205 * Free the termios and termios_locked structures because
3206 * we don't want to get memory leaks when modular tty
3207 * drivers are removed from the kernel.
3209 for (i
= 0; i
< driver
->num
; i
++) {
3210 tp
= driver
->termios
[i
];
3212 driver
->termios
[i
] = NULL
;
3215 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
))
3216 tty_unregister_device(driver
, i
);
3218 proc_tty_unregister_driver(driver
);
3219 if (driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
)
3220 cdev_del(&driver
->cdevs
[0]);
3222 kfree(driver
->cdevs
);
3223 kfree(driver
->ports
);
3224 kfree(driver
->termios
);
3225 kfree(driver
->ttys
);
3229 void tty_driver_kref_put(struct tty_driver
*driver
)
3231 kref_put(&driver
->kref
, destruct_tty_driver
);
3233 EXPORT_SYMBOL(tty_driver_kref_put
);
3235 void tty_set_operations(struct tty_driver
*driver
,
3236 const struct tty_operations
*op
)
3240 EXPORT_SYMBOL(tty_set_operations
);
3242 void put_tty_driver(struct tty_driver
*d
)
3244 tty_driver_kref_put(d
);
3246 EXPORT_SYMBOL(put_tty_driver
);
3249 * Called by a tty driver to register itself.
3251 int tty_register_driver(struct tty_driver
*driver
)
3258 if (!driver
->major
) {
3259 error
= alloc_chrdev_region(&dev
, driver
->minor_start
,
3260 driver
->num
, driver
->name
);
3262 driver
->major
= MAJOR(dev
);
3263 driver
->minor_start
= MINOR(dev
);
3266 dev
= MKDEV(driver
->major
, driver
->minor_start
);
3267 error
= register_chrdev_region(dev
, driver
->num
, driver
->name
);
3272 if (driver
->flags
& TTY_DRIVER_DYNAMIC_ALLOC
) {
3273 error
= tty_cdev_add(driver
, dev
, 0, driver
->num
);
3275 goto err_unreg_char
;
3278 mutex_lock(&tty_mutex
);
3279 list_add(&driver
->tty_drivers
, &tty_drivers
);
3280 mutex_unlock(&tty_mutex
);
3282 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
)) {
3283 for (i
= 0; i
< driver
->num
; i
++) {
3284 d
= tty_register_device(driver
, i
, NULL
);
3287 goto err_unreg_devs
;
3291 proc_tty_register_driver(driver
);
3292 driver
->flags
|= TTY_DRIVER_INSTALLED
;
3296 for (i
--; i
>= 0; i
--)
3297 tty_unregister_device(driver
, i
);
3299 mutex_lock(&tty_mutex
);
3300 list_del(&driver
->tty_drivers
);
3301 mutex_unlock(&tty_mutex
);
3304 unregister_chrdev_region(dev
, driver
->num
);
3308 EXPORT_SYMBOL(tty_register_driver
);
3311 * Called by a tty driver to unregister itself.
3313 int tty_unregister_driver(struct tty_driver
*driver
)
3317 if (driver
->refcount
)
3320 unregister_chrdev_region(MKDEV(driver
->major
, driver
->minor_start
),
3322 mutex_lock(&tty_mutex
);
3323 list_del(&driver
->tty_drivers
);
3324 mutex_unlock(&tty_mutex
);
3328 EXPORT_SYMBOL(tty_unregister_driver
);
3330 dev_t
tty_devnum(struct tty_struct
*tty
)
3332 return MKDEV(tty
->driver
->major
, tty
->driver
->minor_start
) + tty
->index
;
3334 EXPORT_SYMBOL(tty_devnum
);
3336 void proc_clear_tty(struct task_struct
*p
)
3338 unsigned long flags
;
3339 struct tty_struct
*tty
;
3340 spin_lock_irqsave(&p
->sighand
->siglock
, flags
);
3341 tty
= p
->signal
->tty
;
3342 p
->signal
->tty
= NULL
;
3343 spin_unlock_irqrestore(&p
->sighand
->siglock
, flags
);
3347 /* Called under the sighand lock */
3349 static void __proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
)
3352 unsigned long flags
;
3353 /* We should not have a session or pgrp to put here but.... */
3354 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
3355 put_pid(tty
->session
);
3357 tty
->pgrp
= get_pid(task_pgrp(tsk
));
3358 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
3359 tty
->session
= get_pid(task_session(tsk
));
3360 if (tsk
->signal
->tty
) {
3361 printk(KERN_DEBUG
"tty not NULL!!\n");
3362 tty_kref_put(tsk
->signal
->tty
);
3365 put_pid(tsk
->signal
->tty_old_pgrp
);
3366 tsk
->signal
->tty
= tty_kref_get(tty
);
3367 tsk
->signal
->tty_old_pgrp
= NULL
;
3370 static void proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
)
3372 spin_lock_irq(&tsk
->sighand
->siglock
);
3373 __proc_set_tty(tsk
, tty
);
3374 spin_unlock_irq(&tsk
->sighand
->siglock
);
3377 struct tty_struct
*get_current_tty(void)
3379 struct tty_struct
*tty
;
3380 unsigned long flags
;
3382 spin_lock_irqsave(¤t
->sighand
->siglock
, flags
);
3383 tty
= tty_kref_get(current
->signal
->tty
);
3384 spin_unlock_irqrestore(¤t
->sighand
->siglock
, flags
);
3387 EXPORT_SYMBOL_GPL(get_current_tty
);
3389 void tty_default_fops(struct file_operations
*fops
)
3395 * Initialize the console device. This is called *early*, so
3396 * we can't necessarily depend on lots of kernel help here.
3397 * Just do some early initializations, and do the complex setup
3400 void __init
console_init(void)
3404 /* Setup the default TTY line discipline. */
3408 * set up the console device so that later boot sequences can
3409 * inform about problems etc..
3411 call
= __con_initcall_start
;
3412 while (call
< __con_initcall_end
) {
3418 static char *tty_devnode(struct device
*dev
, umode_t
*mode
)
3422 if (dev
->devt
== MKDEV(TTYAUX_MAJOR
, 0) ||
3423 dev
->devt
== MKDEV(TTYAUX_MAJOR
, 2))
3428 static int __init
tty_class_init(void)
3430 tty_class
= class_create(THIS_MODULE
, "tty");
3431 if (IS_ERR(tty_class
))
3432 return PTR_ERR(tty_class
);
3433 tty_class
->devnode
= tty_devnode
;
3437 postcore_initcall(tty_class_init
);
3439 /* 3/2004 jmc: why do these devices exist? */
3440 static struct cdev tty_cdev
, console_cdev
;
3442 static ssize_t
show_cons_active(struct device
*dev
,
3443 struct device_attribute
*attr
, char *buf
)
3445 struct console
*cs
[16];
3451 for_each_console(c
) {
3456 if ((c
->flags
& CON_ENABLED
) == 0)
3459 if (i
>= ARRAY_SIZE(cs
))
3463 count
+= sprintf(buf
+ count
, "%s%d%c",
3464 cs
[i
]->name
, cs
[i
]->index
, i
? ' ':'\n');
3469 static DEVICE_ATTR(active
, S_IRUGO
, show_cons_active
, NULL
);
3471 static struct device
*consdev
;
3473 void console_sysfs_notify(void)
3476 sysfs_notify(&consdev
->kobj
, NULL
, "active");
3480 * Ok, now we can initialize the rest of the tty devices and can count
3481 * on memory allocations, interrupts etc..
3483 int __init
tty_init(void)
3485 cdev_init(&tty_cdev
, &tty_fops
);
3486 if (cdev_add(&tty_cdev
, MKDEV(TTYAUX_MAJOR
, 0), 1) ||
3487 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 0), 1, "/dev/tty") < 0)
3488 panic("Couldn't register /dev/tty driver\n");
3489 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 0), NULL
, "tty");
3491 cdev_init(&console_cdev
, &console_fops
);
3492 if (cdev_add(&console_cdev
, MKDEV(TTYAUX_MAJOR
, 1), 1) ||
3493 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 1), 1, "/dev/console") < 0)
3494 panic("Couldn't register /dev/console driver\n");
3495 consdev
= device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 1), NULL
,
3497 if (IS_ERR(consdev
))
3500 WARN_ON(device_create_file(consdev
, &dev_attr_active
) < 0);
3503 vty_init(&console_fops
);