2 * linux/drivers/char/tty_io.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
8 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
9 * or rs-channels. It also implements echoing, cooked mode etc.
11 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
13 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
14 * tty_struct and tty_queue structures. Previously there was an array
15 * of 256 tty_struct's which was statically allocated, and the
16 * tty_queue structures were allocated at boot time. Both are now
17 * dynamically allocated only when the tty is open.
19 * Also restructured routines so that there is more of a separation
20 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
21 * the low-level tty routines (serial.c, pty.c, console.c). This
22 * makes for cleaner and more compact code. -TYT, 9/17/92
24 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
25 * which can be dynamically activated and de-activated by the line
26 * discipline handling modules (like SLIP).
28 * NOTE: pay no attention to the line discipline code (yet); its
29 * interface is still subject to change in this version...
32 * Added functionality to the OPOST tty handling. No delays, but all
33 * other bits should be there.
34 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
36 * Rewrote canonical mode and added more termios flags.
37 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
39 * Reorganized FASYNC support so mouse code can share it.
40 * -- ctm@ardi.com, 9Sep95
42 * New TIOCLINUX variants added.
43 * -- mj@k332.feld.cvut.cz, 19-Nov-95
45 * Restrict vt switching via ioctl()
46 * -- grif@cs.ucr.edu, 5-Dec-95
48 * Move console and virtual terminal code to more appropriate files,
49 * implement CONFIG_VT and generalize console device interface.
50 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
52 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
53 * -- Bill Hawes <whawes@star.net>, June 97
55 * Added devfs support.
56 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
58 * Added support for a Unix98-style ptmx device.
59 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
61 * Reduced memory usage for older ARM systems
62 * -- Russell King <rmk@arm.linux.org.uk>
64 * Move do_SAK() into process context. Less stack use in devfs functions.
65 * alloc_tty_struct() always uses kmalloc()
66 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
69 #include <linux/types.h>
70 #include <linux/major.h>
71 #include <linux/errno.h>
72 #include <linux/signal.h>
73 #include <linux/fcntl.h>
74 #include <linux/sched.h>
75 #include <linux/interrupt.h>
76 #include <linux/tty.h>
77 #include <linux/tty_driver.h>
78 #include <linux/tty_flip.h>
79 #include <linux/devpts_fs.h>
80 #include <linux/file.h>
81 #include <linux/fdtable.h>
82 #include <linux/console.h>
83 #include <linux/timer.h>
84 #include <linux/ctype.h>
87 #include <linux/string.h>
88 #include <linux/slab.h>
89 #include <linux/poll.h>
90 #include <linux/proc_fs.h>
91 #include <linux/init.h>
92 #include <linux/module.h>
93 #include <linux/smp_lock.h>
94 #include <linux/device.h>
95 #include <linux/wait.h>
96 #include <linux/bitops.h>
97 #include <linux/delay.h>
98 #include <linux/seq_file.h>
100 #include <linux/uaccess.h>
101 #include <asm/system.h>
103 #include <linux/kbd_kern.h>
104 #include <linux/vt_kern.h>
105 #include <linux/selection.h>
107 #include <linux/kmod.h>
108 #include <linux/nsproxy.h>
110 #undef TTY_DEBUG_HANGUP
112 #define TTY_PARANOIA_CHECK 1
113 #define CHECK_TTY_COUNT 1
115 struct ktermios tty_std_termios
= { /* for the benefit of tty drivers */
116 .c_iflag
= ICRNL
| IXON
,
117 .c_oflag
= OPOST
| ONLCR
,
118 .c_cflag
= B38400
| CS8
| CREAD
| HUPCL
,
119 .c_lflag
= ISIG
| ICANON
| ECHO
| ECHOE
| ECHOK
|
120 ECHOCTL
| ECHOKE
| IEXTEN
,
126 EXPORT_SYMBOL(tty_std_termios
);
128 /* This list gets poked at by procfs and various bits of boot up code. This
129 could do with some rationalisation such as pulling the tty proc function
132 LIST_HEAD(tty_drivers
); /* linked list of tty drivers */
134 /* Mutex to protect creating and releasing a tty. This is shared with
135 vt.c for deeply disgusting hack reasons */
136 DEFINE_MUTEX(tty_mutex
);
137 EXPORT_SYMBOL(tty_mutex
);
139 static ssize_t
tty_read(struct file
*, char __user
*, size_t, loff_t
*);
140 static ssize_t
tty_write(struct file
*, const char __user
*, size_t, loff_t
*);
141 ssize_t
redirected_tty_write(struct file
*, const char __user
*,
143 static unsigned int tty_poll(struct file
*, poll_table
*);
144 static int tty_open(struct inode
*, struct file
*);
145 static int tty_release(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 void release_tty(struct tty_struct
*tty
, int idx
);
155 static void __proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
);
156 static void proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
);
159 * alloc_tty_struct - allocate a tty object
161 * Return a new empty tty structure. The data fields have not
162 * been initialized in any way but has been zeroed
167 struct tty_struct
*alloc_tty_struct(void)
169 return kzalloc(sizeof(struct tty_struct
), GFP_KERNEL
);
173 * free_tty_struct - free a disused tty
174 * @tty: tty struct to free
176 * Free the write buffers, tty queue and tty memory itself.
178 * Locking: none. Must be called after tty is definitely unused
181 void free_tty_struct(struct tty_struct
*tty
)
183 kfree(tty
->write_buf
);
184 tty_buffer_free_all(tty
);
188 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
191 * tty_name - return tty naming
192 * @tty: tty structure
193 * @buf: buffer for output
195 * Convert a tty structure into a name. The name reflects the kernel
196 * naming policy and if udev is in use may not reflect user space
201 char *tty_name(struct tty_struct
*tty
, char *buf
)
203 if (!tty
) /* Hmm. NULL pointer. That's fun. */
204 strcpy(buf
, "NULL tty");
206 strcpy(buf
, tty
->name
);
210 EXPORT_SYMBOL(tty_name
);
212 int tty_paranoia_check(struct tty_struct
*tty
, struct inode
*inode
,
215 #ifdef TTY_PARANOIA_CHECK
218 "null TTY for (%d:%d) in %s\n",
219 imajor(inode
), iminor(inode
), routine
);
222 if (tty
->magic
!= TTY_MAGIC
) {
224 "bad magic number for tty struct (%d:%d) in %s\n",
225 imajor(inode
), iminor(inode
), routine
);
232 static int check_tty_count(struct tty_struct
*tty
, const char *routine
)
234 #ifdef CHECK_TTY_COUNT
239 list_for_each(p
, &tty
->tty_files
) {
243 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
244 tty
->driver
->subtype
== PTY_TYPE_SLAVE
&&
245 tty
->link
&& tty
->link
->count
)
247 if (tty
->count
!= count
) {
248 printk(KERN_WARNING
"Warning: dev (%s) tty->count(%d) "
249 "!= #fd's(%d) in %s\n",
250 tty
->name
, tty
->count
, count
, routine
);
258 * get_tty_driver - find device of a tty
259 * @dev_t: device identifier
260 * @index: returns the index of the tty
262 * This routine returns a tty driver structure, given a device number
263 * and also passes back the index number.
265 * Locking: caller must hold tty_mutex
268 static struct tty_driver
*get_tty_driver(dev_t device
, int *index
)
270 struct tty_driver
*p
;
272 list_for_each_entry(p
, &tty_drivers
, tty_drivers
) {
273 dev_t base
= MKDEV(p
->major
, p
->minor_start
);
274 if (device
< base
|| device
>= base
+ p
->num
)
276 *index
= device
- base
;
277 return tty_driver_kref_get(p
);
282 #ifdef CONFIG_CONSOLE_POLL
285 * tty_find_polling_driver - find device of a polled tty
286 * @name: name string to match
287 * @line: pointer to resulting tty line nr
289 * This routine returns a tty driver structure, given a name
290 * and the condition that the tty driver is capable of polled
293 struct tty_driver
*tty_find_polling_driver(char *name
, int *line
)
295 struct tty_driver
*p
, *res
= NULL
;
300 for (str
= name
; *str
; str
++)
301 if ((*str
>= '0' && *str
<= '9') || *str
== ',')
307 tty_line
= simple_strtoul(str
, &str
, 10);
309 mutex_lock(&tty_mutex
);
310 /* Search through the tty devices to look for a match */
311 list_for_each_entry(p
, &tty_drivers
, tty_drivers
) {
312 if (strncmp(name
, p
->name
, len
) != 0)
320 if (tty_line
>= 0 && tty_line
<= p
->num
&& p
->ops
&&
321 p
->ops
->poll_init
&& !p
->ops
->poll_init(p
, tty_line
, stp
)) {
322 res
= tty_driver_kref_get(p
);
327 mutex_unlock(&tty_mutex
);
331 EXPORT_SYMBOL_GPL(tty_find_polling_driver
);
335 * tty_check_change - check for POSIX terminal changes
338 * If we try to write to, or set the state of, a terminal and we're
339 * not in the foreground, send a SIGTTOU. If the signal is blocked or
340 * ignored, go ahead and perform the operation. (POSIX 7.2)
345 int tty_check_change(struct tty_struct
*tty
)
350 if (current
->signal
->tty
!= tty
)
353 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
356 printk(KERN_WARNING
"tty_check_change: tty->pgrp == NULL!\n");
359 if (task_pgrp(current
) == tty
->pgrp
)
361 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
362 if (is_ignored(SIGTTOU
))
364 if (is_current_pgrp_orphaned()) {
368 kill_pgrp(task_pgrp(current
), SIGTTOU
, 1);
369 set_thread_flag(TIF_SIGPENDING
);
374 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
378 EXPORT_SYMBOL(tty_check_change
);
380 static ssize_t
hung_up_tty_read(struct file
*file
, char __user
*buf
,
381 size_t count
, loff_t
*ppos
)
386 static ssize_t
hung_up_tty_write(struct file
*file
, const char __user
*buf
,
387 size_t count
, loff_t
*ppos
)
392 /* No kernel lock held - none needed ;) */
393 static unsigned int hung_up_tty_poll(struct file
*filp
, poll_table
*wait
)
395 return POLLIN
| POLLOUT
| POLLERR
| POLLHUP
| POLLRDNORM
| POLLWRNORM
;
398 static long hung_up_tty_ioctl(struct file
*file
, unsigned int cmd
,
401 return cmd
== TIOCSPGRP
? -ENOTTY
: -EIO
;
404 static long hung_up_tty_compat_ioctl(struct file
*file
,
405 unsigned int cmd
, unsigned long arg
)
407 return cmd
== TIOCSPGRP
? -ENOTTY
: -EIO
;
410 static const struct file_operations tty_fops
= {
415 .unlocked_ioctl
= tty_ioctl
,
416 .compat_ioctl
= tty_compat_ioctl
,
418 .release
= tty_release
,
419 .fasync
= tty_fasync
,
422 static const struct file_operations console_fops
= {
425 .write
= redirected_tty_write
,
427 .unlocked_ioctl
= tty_ioctl
,
428 .compat_ioctl
= tty_compat_ioctl
,
430 .release
= tty_release
,
431 .fasync
= tty_fasync
,
434 static const struct file_operations hung_up_tty_fops
= {
436 .read
= hung_up_tty_read
,
437 .write
= hung_up_tty_write
,
438 .poll
= hung_up_tty_poll
,
439 .unlocked_ioctl
= hung_up_tty_ioctl
,
440 .compat_ioctl
= hung_up_tty_compat_ioctl
,
441 .release
= tty_release
,
444 static DEFINE_SPINLOCK(redirect_lock
);
445 static struct file
*redirect
;
448 * tty_wakeup - request more data
451 * Internal and external helper for wakeups of tty. This function
452 * informs the line discipline if present that the driver is ready
453 * to receive more output data.
456 void tty_wakeup(struct tty_struct
*tty
)
458 struct tty_ldisc
*ld
;
460 if (test_bit(TTY_DO_WRITE_WAKEUP
, &tty
->flags
)) {
461 ld
= tty_ldisc_ref(tty
);
463 if (ld
->ops
->write_wakeup
)
464 ld
->ops
->write_wakeup(tty
);
468 wake_up_interruptible_poll(&tty
->write_wait
, POLLOUT
);
471 EXPORT_SYMBOL_GPL(tty_wakeup
);
474 * do_tty_hangup - actual handler for hangup events
477 * This can be called by the "eventd" kernel thread. That is process
478 * synchronous but doesn't hold any locks, so we need to make sure we
479 * have the appropriate locks for what we're doing.
481 * The hangup event clears any pending redirections onto the hung up
482 * device. It ensures future writes will error and it does the needed
483 * line discipline hangup and signal delivery. The tty object itself
488 * redirect lock for undoing redirection
489 * file list lock for manipulating list of ttys
490 * tty_ldisc_lock from called functions
491 * termios_mutex resetting termios data
492 * tasklist_lock to walk task list for hangup event
493 * ->siglock to protect ->signal/->sighand
495 static void do_tty_hangup(struct work_struct
*work
)
497 struct tty_struct
*tty
=
498 container_of(work
, struct tty_struct
, hangup_work
);
499 struct file
*cons_filp
= NULL
;
500 struct file
*filp
, *f
= NULL
;
501 struct task_struct
*p
;
502 int closecount
= 0, n
;
509 /* inuse_filps is protected by the single kernel lock */
512 spin_lock(&redirect_lock
);
513 if (redirect
&& redirect
->private_data
== tty
) {
517 spin_unlock(&redirect_lock
);
519 check_tty_count(tty
, "do_tty_hangup");
521 /* This breaks for file handles being sent over AF_UNIX sockets ? */
522 list_for_each_entry(filp
, &tty
->tty_files
, f_u
.fu_list
) {
523 if (filp
->f_op
->write
== redirected_tty_write
)
525 if (filp
->f_op
->write
!= tty_write
)
528 tty_fasync(-1, filp
, 0); /* can't block */
529 filp
->f_op
= &hung_up_tty_fops
;
533 tty_ldisc_hangup(tty
);
535 read_lock(&tasklist_lock
);
537 do_each_pid_task(tty
->session
, PIDTYPE_SID
, p
) {
538 spin_lock_irq(&p
->sighand
->siglock
);
539 if (p
->signal
->tty
== tty
) {
540 p
->signal
->tty
= NULL
;
541 /* We defer the dereferences outside fo
545 if (!p
->signal
->leader
) {
546 spin_unlock_irq(&p
->sighand
->siglock
);
549 __group_send_sig_info(SIGHUP
, SEND_SIG_PRIV
, p
);
550 __group_send_sig_info(SIGCONT
, SEND_SIG_PRIV
, p
);
551 put_pid(p
->signal
->tty_old_pgrp
); /* A noop */
552 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
554 p
->signal
->tty_old_pgrp
= get_pid(tty
->pgrp
);
555 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
556 spin_unlock_irq(&p
->sighand
->siglock
);
557 } while_each_pid_task(tty
->session
, PIDTYPE_SID
, p
);
559 read_unlock(&tasklist_lock
);
561 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
562 clear_bit(TTY_THROTTLED
, &tty
->flags
);
563 clear_bit(TTY_PUSH
, &tty
->flags
);
564 clear_bit(TTY_DO_WRITE_WAKEUP
, &tty
->flags
);
565 put_pid(tty
->session
);
569 tty
->ctrl_status
= 0;
570 set_bit(TTY_HUPPED
, &tty
->flags
);
571 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
573 /* Account for the p->signal references we killed */
578 * If one of the devices matches a console pointer, we
579 * cannot just call hangup() because that will cause
580 * tty->count and state->count to go out of sync.
581 * So we just call close() the right number of times.
585 for (n
= 0; n
< closecount
; n
++)
586 tty
->ops
->close(tty
, cons_filp
);
587 } else if (tty
->ops
->hangup
)
588 (tty
->ops
->hangup
)(tty
);
590 * We don't want to have driver/ldisc interactions beyond
591 * the ones we did here. The driver layer expects no
592 * calls after ->hangup() from the ldisc side. However we
593 * can't yet guarantee all that.
595 set_bit(TTY_HUPPED
, &tty
->flags
);
596 tty_ldisc_enable(tty
);
603 * tty_hangup - trigger a hangup event
604 * @tty: tty to hangup
606 * A carrier loss (virtual or otherwise) has occurred on this like
607 * schedule a hangup sequence to run after this event.
610 void tty_hangup(struct tty_struct
*tty
)
612 #ifdef TTY_DEBUG_HANGUP
614 printk(KERN_DEBUG
"%s hangup...\n", tty_name(tty
, buf
));
616 schedule_work(&tty
->hangup_work
);
619 EXPORT_SYMBOL(tty_hangup
);
622 * tty_vhangup - process vhangup
623 * @tty: tty to hangup
625 * The user has asked via system call for the terminal to be hung up.
626 * We do this synchronously so that when the syscall returns the process
627 * is complete. That guarantee is necessary for security reasons.
630 void tty_vhangup(struct tty_struct
*tty
)
632 #ifdef TTY_DEBUG_HANGUP
635 printk(KERN_DEBUG
"%s vhangup...\n", tty_name(tty
, buf
));
637 do_tty_hangup(&tty
->hangup_work
);
640 EXPORT_SYMBOL(tty_vhangup
);
643 * tty_vhangup_self - process vhangup for own ctty
645 * Perform a vhangup on the current controlling tty
648 void tty_vhangup_self(void)
650 struct tty_struct
*tty
;
652 tty
= get_current_tty();
660 * tty_hung_up_p - was tty hung up
661 * @filp: file pointer of tty
663 * Return true if the tty has been subject to a vhangup or a carrier
667 int tty_hung_up_p(struct file
*filp
)
669 return (filp
->f_op
== &hung_up_tty_fops
);
672 EXPORT_SYMBOL(tty_hung_up_p
);
674 static void session_clear_tty(struct pid
*session
)
676 struct task_struct
*p
;
677 do_each_pid_task(session
, PIDTYPE_SID
, p
) {
679 } while_each_pid_task(session
, PIDTYPE_SID
, p
);
683 * disassociate_ctty - disconnect controlling tty
684 * @on_exit: true if exiting so need to "hang up" the session
686 * This function is typically called only by the session leader, when
687 * it wants to disassociate itself from its controlling tty.
689 * It performs the following functions:
690 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
691 * (2) Clears the tty from being controlling the session
692 * (3) Clears the controlling tty for all processes in the
695 * The argument on_exit is set to 1 if called when a process is
696 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
699 * BKL is taken for hysterical raisins
700 * tty_mutex is taken to protect tty
701 * ->siglock is taken to protect ->signal/->sighand
702 * tasklist_lock is taken to walk process list for sessions
703 * ->siglock is taken to protect ->signal/->sighand
706 void disassociate_ctty(int on_exit
)
708 struct tty_struct
*tty
;
709 struct pid
*tty_pgrp
= NULL
;
712 tty
= get_current_tty();
714 tty_pgrp
= get_pid(tty
->pgrp
);
716 if (on_exit
&& tty
->driver
->type
!= TTY_DRIVER_TYPE_PTY
)
720 } else if (on_exit
) {
721 struct pid
*old_pgrp
;
722 spin_lock_irq(¤t
->sighand
->siglock
);
723 old_pgrp
= current
->signal
->tty_old_pgrp
;
724 current
->signal
->tty_old_pgrp
= NULL
;
725 spin_unlock_irq(¤t
->sighand
->siglock
);
727 kill_pgrp(old_pgrp
, SIGHUP
, on_exit
);
728 kill_pgrp(old_pgrp
, SIGCONT
, on_exit
);
734 kill_pgrp(tty_pgrp
, SIGHUP
, on_exit
);
736 kill_pgrp(tty_pgrp
, SIGCONT
, on_exit
);
740 spin_lock_irq(¤t
->sighand
->siglock
);
741 put_pid(current
->signal
->tty_old_pgrp
);
742 current
->signal
->tty_old_pgrp
= NULL
;
743 spin_unlock_irq(¤t
->sighand
->siglock
);
745 tty
= get_current_tty();
748 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
749 put_pid(tty
->session
);
753 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
756 #ifdef TTY_DEBUG_HANGUP
757 printk(KERN_DEBUG
"error attempted to write to tty [0x%p]"
762 /* Now clear signal->tty under the lock */
763 read_lock(&tasklist_lock
);
764 session_clear_tty(task_session(current
));
765 read_unlock(&tasklist_lock
);
770 * no_tty - Ensure the current process does not have a controlling tty
774 struct task_struct
*tsk
= current
;
776 if (tsk
->signal
->leader
)
777 disassociate_ctty(0);
784 * stop_tty - propagate flow control
787 * Perform flow control to the driver. For PTY/TTY pairs we
788 * must also propagate the TIOCKPKT status. May be called
789 * on an already stopped device and will not re-call the driver
792 * This functionality is used by both the line disciplines for
793 * halting incoming flow and by the driver. It may therefore be
794 * called from any context, may be under the tty atomic_write_lock
798 * Uses the tty control lock internally
801 void stop_tty(struct tty_struct
*tty
)
804 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
806 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
810 if (tty
->link
&& tty
->link
->packet
) {
811 tty
->ctrl_status
&= ~TIOCPKT_START
;
812 tty
->ctrl_status
|= TIOCPKT_STOP
;
813 wake_up_interruptible_poll(&tty
->link
->read_wait
, POLLIN
);
815 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
817 (tty
->ops
->stop
)(tty
);
820 EXPORT_SYMBOL(stop_tty
);
823 * start_tty - propagate flow control
826 * Start a tty that has been stopped if at all possible. Perform
827 * any necessary wakeups and propagate the TIOCPKT status. If this
828 * is the tty was previous stopped and is being started then the
829 * driver start method is invoked and the line discipline woken.
835 void start_tty(struct tty_struct
*tty
)
838 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
839 if (!tty
->stopped
|| tty
->flow_stopped
) {
840 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
844 if (tty
->link
&& tty
->link
->packet
) {
845 tty
->ctrl_status
&= ~TIOCPKT_STOP
;
846 tty
->ctrl_status
|= TIOCPKT_START
;
847 wake_up_interruptible_poll(&tty
->link
->read_wait
, POLLIN
);
849 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
851 (tty
->ops
->start
)(tty
);
852 /* If we have a running line discipline it may need kicking */
856 EXPORT_SYMBOL(start_tty
);
859 * tty_read - read method for tty device files
860 * @file: pointer to tty file
862 * @count: size of user buffer
865 * Perform the read system call function on this terminal device. Checks
866 * for hung up devices before calling the line discipline method.
869 * Locks the line discipline internally while needed. Multiple
870 * read calls may be outstanding in parallel.
873 static ssize_t
tty_read(struct file
*file
, char __user
*buf
, size_t count
,
877 struct tty_struct
*tty
;
879 struct tty_ldisc
*ld
;
881 tty
= (struct tty_struct
*)file
->private_data
;
882 inode
= file
->f_path
.dentry
->d_inode
;
883 if (tty_paranoia_check(tty
, inode
, "tty_read"))
885 if (!tty
|| (test_bit(TTY_IO_ERROR
, &tty
->flags
)))
888 /* We want to wait for the line discipline to sort out in this
890 ld
= tty_ldisc_ref_wait(tty
);
892 i
= (ld
->ops
->read
)(tty
, file
, buf
, count
);
897 inode
->i_atime
= current_fs_time(inode
->i_sb
);
901 void tty_write_unlock(struct tty_struct
*tty
)
903 mutex_unlock(&tty
->atomic_write_lock
);
904 wake_up_interruptible_poll(&tty
->write_wait
, POLLOUT
);
907 int tty_write_lock(struct tty_struct
*tty
, int ndelay
)
909 if (!mutex_trylock(&tty
->atomic_write_lock
)) {
912 if (mutex_lock_interruptible(&tty
->atomic_write_lock
))
919 * Split writes up in sane blocksizes to avoid
920 * denial-of-service type attacks
922 static inline ssize_t
do_tty_write(
923 ssize_t (*write
)(struct tty_struct
*, struct file
*, const unsigned char *, size_t),
924 struct tty_struct
*tty
,
926 const char __user
*buf
,
929 ssize_t ret
, written
= 0;
932 ret
= tty_write_lock(tty
, file
->f_flags
& O_NDELAY
);
937 * We chunk up writes into a temporary buffer. This
938 * simplifies low-level drivers immensely, since they
939 * don't have locking issues and user mode accesses.
941 * But if TTY_NO_WRITE_SPLIT is set, we should use a
944 * The default chunk-size is 2kB, because the NTTY
945 * layer has problems with bigger chunks. It will
946 * claim to be able to handle more characters than
949 * FIXME: This can probably go away now except that 64K chunks
950 * are too likely to fail unless switched to vmalloc...
953 if (test_bit(TTY_NO_WRITE_SPLIT
, &tty
->flags
))
958 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
959 if (tty
->write_cnt
< chunk
) {
960 unsigned char *buf_chunk
;
965 buf_chunk
= kmalloc(chunk
, GFP_KERNEL
);
970 kfree(tty
->write_buf
);
971 tty
->write_cnt
= chunk
;
972 tty
->write_buf
= buf_chunk
;
975 /* Do the write .. */
981 if (copy_from_user(tty
->write_buf
, buf
, size
))
983 ret
= write(tty
, file
, tty
->write_buf
, size
);
992 if (signal_pending(current
))
997 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
998 inode
->i_mtime
= current_fs_time(inode
->i_sb
);
1002 tty_write_unlock(tty
);
1007 * tty_write_message - write a message to a certain tty, not just the console.
1008 * @tty: the destination tty_struct
1009 * @msg: the message to write
1011 * This is used for messages that need to be redirected to a specific tty.
1012 * We don't put it into the syslog queue right now maybe in the future if
1015 * We must still hold the BKL and test the CLOSING flag for the moment.
1018 void tty_write_message(struct tty_struct
*tty
, char *msg
)
1022 mutex_lock(&tty
->atomic_write_lock
);
1023 if (tty
->ops
->write
&& !test_bit(TTY_CLOSING
, &tty
->flags
))
1024 tty
->ops
->write(tty
, msg
, strlen(msg
));
1025 tty_write_unlock(tty
);
1033 * tty_write - write method for tty device file
1034 * @file: tty file pointer
1035 * @buf: user data to write
1036 * @count: bytes to write
1039 * Write data to a tty device via the line discipline.
1042 * Locks the line discipline as required
1043 * Writes to the tty driver are serialized by the atomic_write_lock
1044 * and are then processed in chunks to the device. The line discipline
1045 * write method will not be invoked in parallel for each device.
1048 static ssize_t
tty_write(struct file
*file
, const char __user
*buf
,
1049 size_t count
, loff_t
*ppos
)
1051 struct tty_struct
*tty
;
1052 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
1054 struct tty_ldisc
*ld
;
1056 tty
= (struct tty_struct
*)file
->private_data
;
1057 if (tty_paranoia_check(tty
, inode
, "tty_write"))
1059 if (!tty
|| !tty
->ops
->write
||
1060 (test_bit(TTY_IO_ERROR
, &tty
->flags
)))
1062 /* Short term debug to catch buggy drivers */
1063 if (tty
->ops
->write_room
== NULL
)
1064 printk(KERN_ERR
"tty driver %s lacks a write_room method.\n",
1066 ld
= tty_ldisc_ref_wait(tty
);
1067 if (!ld
->ops
->write
)
1070 ret
= do_tty_write(ld
->ops
->write
, tty
, file
, buf
, count
);
1071 tty_ldisc_deref(ld
);
1075 ssize_t
redirected_tty_write(struct file
*file
, const char __user
*buf
,
1076 size_t count
, loff_t
*ppos
)
1078 struct file
*p
= NULL
;
1080 spin_lock(&redirect_lock
);
1085 spin_unlock(&redirect_lock
);
1089 res
= vfs_write(p
, buf
, count
, &p
->f_pos
);
1093 return tty_write(file
, buf
, count
, ppos
);
1096 static char ptychar
[] = "pqrstuvwxyzabcde";
1099 * pty_line_name - generate name for a pty
1100 * @driver: the tty driver in use
1101 * @index: the minor number
1102 * @p: output buffer of at least 6 bytes
1104 * Generate a name from a driver reference and write it to the output
1109 static void pty_line_name(struct tty_driver
*driver
, int index
, char *p
)
1111 int i
= index
+ driver
->name_base
;
1112 /* ->name is initialized to "ttyp", but "tty" is expected */
1113 sprintf(p
, "%s%c%x",
1114 driver
->subtype
== PTY_TYPE_SLAVE
? "tty" : driver
->name
,
1115 ptychar
[i
>> 4 & 0xf], i
& 0xf);
1119 * tty_line_name - generate name for a tty
1120 * @driver: the tty driver in use
1121 * @index: the minor number
1122 * @p: output buffer of at least 7 bytes
1124 * Generate a name from a driver reference and write it to the output
1129 static void tty_line_name(struct tty_driver
*driver
, int index
, char *p
)
1131 sprintf(p
, "%s%d", driver
->name
, index
+ driver
->name_base
);
1135 * tty_driver_lookup_tty() - find an existing tty, if any
1136 * @driver: the driver for the tty
1137 * @idx: the minor number
1139 * Return the tty, if found or ERR_PTR() otherwise.
1141 * Locking: tty_mutex must be held. If tty is found, the mutex must
1142 * be held until the 'fast-open' is also done. Will change once we
1143 * have refcounting in the driver and per driver locking
1145 static struct tty_struct
*tty_driver_lookup_tty(struct tty_driver
*driver
,
1146 struct inode
*inode
, int idx
)
1148 struct tty_struct
*tty
;
1150 if (driver
->ops
->lookup
)
1151 return driver
->ops
->lookup(driver
, inode
, idx
);
1153 tty
= driver
->ttys
[idx
];
1158 * tty_init_termios - helper for termios setup
1159 * @tty: the tty to set up
1161 * Initialise the termios structures for this tty. Thus runs under
1162 * the tty_mutex currently so we can be relaxed about ordering.
1165 int tty_init_termios(struct tty_struct
*tty
)
1167 struct ktermios
*tp
;
1168 int idx
= tty
->index
;
1170 tp
= tty
->driver
->termios
[idx
];
1172 tp
= kzalloc(sizeof(struct ktermios
[2]), GFP_KERNEL
);
1175 memcpy(tp
, &tty
->driver
->init_termios
,
1176 sizeof(struct ktermios
));
1177 tty
->driver
->termios
[idx
] = tp
;
1180 tty
->termios_locked
= tp
+ 1;
1182 /* Compatibility until drivers always set this */
1183 tty
->termios
->c_ispeed
= tty_termios_input_baud_rate(tty
->termios
);
1184 tty
->termios
->c_ospeed
= tty_termios_baud_rate(tty
->termios
);
1189 * tty_driver_install_tty() - install a tty entry in the driver
1190 * @driver: the driver for the tty
1193 * Install a tty object into the driver tables. The tty->index field
1194 * will be set by the time this is called. This method is responsible
1195 * for ensuring any need additional structures are allocated and
1198 * Locking: tty_mutex for now
1200 static int tty_driver_install_tty(struct tty_driver
*driver
,
1201 struct tty_struct
*tty
)
1203 int idx
= tty
->index
;
1205 if (driver
->ops
->install
)
1206 return driver
->ops
->install(driver
, tty
);
1208 if (tty_init_termios(tty
) == 0) {
1209 tty_driver_kref_get(driver
);
1211 driver
->ttys
[idx
] = tty
;
1218 * tty_driver_remove_tty() - remove a tty from the driver tables
1219 * @driver: the driver for the tty
1220 * @idx: the minor number
1222 * Remvoe a tty object from the driver tables. The tty->index field
1223 * will be set by the time this is called.
1225 * Locking: tty_mutex for now
1227 static void tty_driver_remove_tty(struct tty_driver
*driver
,
1228 struct tty_struct
*tty
)
1230 if (driver
->ops
->remove
)
1231 driver
->ops
->remove(driver
, tty
);
1233 driver
->ttys
[tty
->index
] = NULL
;
1237 * tty_reopen() - fast re-open of an open tty
1238 * @tty - the tty to open
1240 * Return 0 on success, -errno on error.
1242 * Locking: tty_mutex must be held from the time the tty was found
1243 * till this open completes.
1245 static int tty_reopen(struct tty_struct
*tty
)
1247 struct tty_driver
*driver
= tty
->driver
;
1249 if (test_bit(TTY_CLOSING
, &tty
->flags
))
1252 if (driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1253 driver
->subtype
== PTY_TYPE_MASTER
) {
1255 * special case for PTY masters: only one open permitted,
1256 * and the slave side open count is incremented as well.
1264 tty
->driver
= driver
; /* N.B. why do this every time?? */
1266 WARN_ON(!test_bit(TTY_LDISC
, &tty
->flags
));
1272 * tty_init_dev - initialise a tty device
1273 * @driver: tty driver we are opening a device on
1274 * @idx: device index
1275 * @ret_tty: returned tty structure
1276 * @first_ok: ok to open a new device (used by ptmx)
1278 * Prepare a tty device. This may not be a "new" clean device but
1279 * could also be an active device. The pty drivers require special
1280 * handling because of this.
1283 * The function is called under the tty_mutex, which
1284 * protects us from the tty struct or driver itself going away.
1286 * On exit the tty device has the line discipline attached and
1287 * a reference count of 1. If a pair was created for pty/tty use
1288 * and the other was a pty master then it too has a reference count of 1.
1290 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1291 * failed open. The new code protects the open with a mutex, so it's
1292 * really quite straightforward. The mutex locking can probably be
1293 * relaxed for the (most common) case of reopening a tty.
1296 struct tty_struct
*tty_init_dev(struct tty_driver
*driver
, int idx
,
1299 struct tty_struct
*tty
;
1302 /* Check if pty master is being opened multiple times */
1303 if (driver
->subtype
== PTY_TYPE_MASTER
&&
1304 (driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) && !first_ok
)
1305 return ERR_PTR(-EIO
);
1308 * First time open is complex, especially for PTY devices.
1309 * This code guarantees that either everything succeeds and the
1310 * TTY is ready for operation, or else the table slots are vacated
1311 * and the allocated memory released. (Except that the termios
1312 * and locked termios may be retained.)
1315 if (!try_module_get(driver
->owner
))
1316 return ERR_PTR(-ENODEV
);
1318 tty
= alloc_tty_struct();
1321 initialize_tty_struct(tty
, driver
, idx
);
1323 retval
= tty_driver_install_tty(driver
, tty
);
1325 free_tty_struct(tty
);
1326 module_put(driver
->owner
);
1327 return ERR_PTR(retval
);
1331 * Structures all installed ... call the ldisc open routines.
1332 * If we fail here just call release_tty to clean up. No need
1333 * to decrement the use counts, as release_tty doesn't care.
1336 retval
= tty_ldisc_setup(tty
, tty
->link
);
1338 goto release_mem_out
;
1342 module_put(driver
->owner
);
1343 return ERR_PTR(-ENOMEM
);
1345 /* call the tty release_tty routine to clean out this slot */
1347 if (printk_ratelimit())
1348 printk(KERN_INFO
"tty_init_dev: ldisc open failed, "
1349 "clearing slot %d\n", idx
);
1350 release_tty(tty
, idx
);
1351 return ERR_PTR(retval
);
1354 void tty_free_termios(struct tty_struct
*tty
)
1356 struct ktermios
*tp
;
1357 int idx
= tty
->index
;
1358 /* Kill this flag and push into drivers for locking etc */
1359 if (tty
->driver
->flags
& TTY_DRIVER_RESET_TERMIOS
) {
1360 /* FIXME: Locking on ->termios array */
1362 tty
->driver
->termios
[idx
] = NULL
;
1366 EXPORT_SYMBOL(tty_free_termios
);
1368 void tty_shutdown(struct tty_struct
*tty
)
1370 tty_driver_remove_tty(tty
->driver
, tty
);
1371 tty_free_termios(tty
);
1373 EXPORT_SYMBOL(tty_shutdown
);
1376 * release_one_tty - release tty structure memory
1377 * @kref: kref of tty we are obliterating
1379 * Releases memory associated with a tty structure, and clears out the
1380 * driver table slots. This function is called when a device is no longer
1381 * in use. It also gets called when setup of a device fails.
1384 * tty_mutex - sometimes only
1385 * takes the file list lock internally when working on the list
1386 * of ttys that the driver keeps.
1388 static void release_one_tty(struct kref
*kref
)
1390 struct tty_struct
*tty
= container_of(kref
, struct tty_struct
, kref
);
1391 struct tty_driver
*driver
= tty
->driver
;
1393 if (tty
->ops
->shutdown
)
1394 tty
->ops
->shutdown(tty
);
1398 tty_driver_kref_put(driver
);
1399 module_put(driver
->owner
);
1402 list_del_init(&tty
->tty_files
);
1405 free_tty_struct(tty
);
1409 * tty_kref_put - release a tty kref
1412 * Release a reference to a tty device and if need be let the kref
1413 * layer destruct the object for us
1416 void tty_kref_put(struct tty_struct
*tty
)
1419 kref_put(&tty
->kref
, release_one_tty
);
1421 EXPORT_SYMBOL(tty_kref_put
);
1424 * release_tty - release tty structure memory
1426 * Release both @tty and a possible linked partner (think pty pair),
1427 * and decrement the refcount of the backing module.
1430 * tty_mutex - sometimes only
1431 * takes the file list lock internally when working on the list
1432 * of ttys that the driver keeps.
1433 * FIXME: should we require tty_mutex is held here ??
1436 static void release_tty(struct tty_struct
*tty
, int idx
)
1438 /* This should always be true but check for the moment */
1439 WARN_ON(tty
->index
!= idx
);
1442 tty_kref_put(tty
->link
);
1447 * Even releasing the tty structures is a tricky business.. We have
1448 * to be very careful that the structures are all released at the
1449 * same time, as interrupts might otherwise get the wrong pointers.
1451 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1452 * lead to double frees or releasing memory still in use.
1454 void tty_release_dev(struct file
*filp
)
1456 struct tty_struct
*tty
, *o_tty
;
1457 int pty_master
, tty_closing
, o_tty_closing
, do_sleep
;
1461 struct inode
*inode
;
1463 inode
= filp
->f_path
.dentry
->d_inode
;
1464 tty
= (struct tty_struct
*)filp
->private_data
;
1465 if (tty_paranoia_check(tty
, inode
, "tty_release_dev"))
1468 check_tty_count(tty
, "tty_release_dev");
1470 tty_fasync(-1, filp
, 0);
1473 pty_master
= (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1474 tty
->driver
->subtype
== PTY_TYPE_MASTER
);
1475 devpts
= (tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) != 0;
1478 #ifdef TTY_PARANOIA_CHECK
1479 if (idx
< 0 || idx
>= tty
->driver
->num
) {
1480 printk(KERN_DEBUG
"tty_release_dev: bad idx when trying to "
1481 "free (%s)\n", tty
->name
);
1485 if (tty
!= tty
->driver
->ttys
[idx
]) {
1486 printk(KERN_DEBUG
"tty_release_dev: driver.table[%d] not tty "
1487 "for (%s)\n", idx
, tty
->name
);
1490 if (tty
->termios
!= tty
->driver
->termios
[idx
]) {
1491 printk(KERN_DEBUG
"tty_release_dev: driver.termios[%d] not termios "
1499 #ifdef TTY_DEBUG_HANGUP
1500 printk(KERN_DEBUG
"tty_release_dev of %s (tty count=%d)...",
1501 tty_name(tty
, buf
), tty
->count
);
1504 #ifdef TTY_PARANOIA_CHECK
1505 if (tty
->driver
->other
&&
1506 !(tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
)) {
1507 if (o_tty
!= tty
->driver
->other
->ttys
[idx
]) {
1508 printk(KERN_DEBUG
"tty_release_dev: other->table[%d] "
1509 "not o_tty for (%s)\n",
1513 if (o_tty
->termios
!= tty
->driver
->other
->termios
[idx
]) {
1514 printk(KERN_DEBUG
"tty_release_dev: other->termios[%d] "
1515 "not o_termios for (%s)\n",
1519 if (o_tty
->link
!= tty
) {
1520 printk(KERN_DEBUG
"tty_release_dev: bad pty pointers\n");
1525 if (tty
->ops
->close
)
1526 tty
->ops
->close(tty
, filp
);
1529 * Sanity check: if tty->count is going to zero, there shouldn't be
1530 * any waiters on tty->read_wait or tty->write_wait. We test the
1531 * wait queues and kick everyone out _before_ actually starting to
1532 * close. This ensures that we won't block while releasing the tty
1535 * The test for the o_tty closing is necessary, since the master and
1536 * slave sides may close in any order. If the slave side closes out
1537 * first, its count will be one, since the master side holds an open.
1538 * Thus this test wouldn't be triggered at the time the slave closes,
1541 * Note that it's possible for the tty to be opened again while we're
1542 * flushing out waiters. By recalculating the closing flags before
1543 * each iteration we avoid any problems.
1546 /* Guard against races with tty->count changes elsewhere and
1547 opens on /dev/tty */
1549 mutex_lock(&tty_mutex
);
1550 tty_closing
= tty
->count
<= 1;
1551 o_tty_closing
= o_tty
&&
1552 (o_tty
->count
<= (pty_master
? 1 : 0));
1556 if (waitqueue_active(&tty
->read_wait
)) {
1557 wake_up_poll(&tty
->read_wait
, POLLIN
);
1560 if (waitqueue_active(&tty
->write_wait
)) {
1561 wake_up_poll(&tty
->write_wait
, POLLOUT
);
1565 if (o_tty_closing
) {
1566 if (waitqueue_active(&o_tty
->read_wait
)) {
1567 wake_up_poll(&o_tty
->read_wait
, POLLIN
);
1570 if (waitqueue_active(&o_tty
->write_wait
)) {
1571 wake_up_poll(&o_tty
->write_wait
, POLLOUT
);
1578 printk(KERN_WARNING
"tty_release_dev: %s: read/write wait queue "
1579 "active!\n", tty_name(tty
, buf
));
1580 mutex_unlock(&tty_mutex
);
1585 * The closing flags are now consistent with the open counts on
1586 * both sides, and we've completed the last operation that could
1587 * block, so it's safe to proceed with closing.
1590 if (--o_tty
->count
< 0) {
1591 printk(KERN_WARNING
"tty_release_dev: bad pty slave count "
1593 o_tty
->count
, tty_name(o_tty
, buf
));
1597 if (--tty
->count
< 0) {
1598 printk(KERN_WARNING
"tty_release_dev: bad tty->count (%d) for %s\n",
1599 tty
->count
, tty_name(tty
, buf
));
1604 * We've decremented tty->count, so we need to remove this file
1605 * descriptor off the tty->tty_files list; this serves two
1607 * - check_tty_count sees the correct number of file descriptors
1608 * associated with this tty.
1609 * - do_tty_hangup no longer sees this file descriptor as
1610 * something that needs to be handled for hangups.
1613 filp
->private_data
= NULL
;
1616 * Perform some housekeeping before deciding whether to return.
1618 * Set the TTY_CLOSING flag if this was the last open. In the
1619 * case of a pty we may have to wait around for the other side
1620 * to close, and TTY_CLOSING makes sure we can't be reopened.
1623 set_bit(TTY_CLOSING
, &tty
->flags
);
1625 set_bit(TTY_CLOSING
, &o_tty
->flags
);
1628 * If _either_ side is closing, make sure there aren't any
1629 * processes that still think tty or o_tty is their controlling
1632 if (tty_closing
|| o_tty_closing
) {
1633 read_lock(&tasklist_lock
);
1634 session_clear_tty(tty
->session
);
1636 session_clear_tty(o_tty
->session
);
1637 read_unlock(&tasklist_lock
);
1640 mutex_unlock(&tty_mutex
);
1642 /* check whether both sides are closing ... */
1643 if (!tty_closing
|| (o_tty
&& !o_tty_closing
))
1646 #ifdef TTY_DEBUG_HANGUP
1647 printk(KERN_DEBUG
"freeing tty structure...");
1650 * Ask the line discipline code to release its structures
1652 tty_ldisc_release(tty
, o_tty
);
1654 * The release_tty function takes care of the details of clearing
1655 * the slots and preserving the termios structure.
1657 release_tty(tty
, idx
);
1659 /* Make this pty number available for reallocation */
1661 devpts_kill_index(inode
, idx
);
1665 * __tty_open - open a tty device
1666 * @inode: inode of device file
1667 * @filp: file pointer to tty
1669 * tty_open and tty_release keep up the tty count that contains the
1670 * number of opens done on a tty. We cannot use the inode-count, as
1671 * different inodes might point to the same tty.
1673 * Open-counting is needed for pty masters, as well as for keeping
1674 * track of serial lines: DTR is dropped when the last close happens.
1675 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1677 * The termios state of a pty is reset on first open so that
1678 * settings don't persist across reuse.
1680 * Locking: tty_mutex protects tty, get_tty_driver and tty_init_dev work.
1681 * tty->count should protect the rest.
1682 * ->siglock protects ->signal/->sighand
1685 static int __tty_open(struct inode
*inode
, struct file
*filp
)
1687 struct tty_struct
*tty
= NULL
;
1689 struct tty_driver
*driver
;
1691 dev_t device
= inode
->i_rdev
;
1692 unsigned saved_flags
= filp
->f_flags
;
1694 nonseekable_open(inode
, filp
);
1697 noctty
= filp
->f_flags
& O_NOCTTY
;
1701 mutex_lock(&tty_mutex
);
1703 if (device
== MKDEV(TTYAUX_MAJOR
, 0)) {
1704 tty
= get_current_tty();
1706 mutex_unlock(&tty_mutex
);
1709 driver
= tty_driver_kref_get(tty
->driver
);
1711 filp
->f_flags
|= O_NONBLOCK
; /* Don't let /dev/tty block */
1713 /* FIXME: Should we take a driver reference ? */
1718 if (device
== MKDEV(TTY_MAJOR
, 0)) {
1719 extern struct tty_driver
*console_driver
;
1720 driver
= tty_driver_kref_get(console_driver
);
1726 if (device
== MKDEV(TTYAUX_MAJOR
, 1)) {
1727 struct tty_driver
*console_driver
= console_device(&index
);
1728 if (console_driver
) {
1729 driver
= tty_driver_kref_get(console_driver
);
1731 /* Don't let /dev/console block */
1732 filp
->f_flags
|= O_NONBLOCK
;
1737 mutex_unlock(&tty_mutex
);
1741 driver
= get_tty_driver(device
, &index
);
1743 mutex_unlock(&tty_mutex
);
1748 /* check whether we're reopening an existing tty */
1749 tty
= tty_driver_lookup_tty(driver
, inode
, index
);
1752 mutex_unlock(&tty_mutex
);
1753 return PTR_ERR(tty
);
1758 retval
= tty_reopen(tty
);
1760 tty
= ERR_PTR(retval
);
1762 tty
= tty_init_dev(driver
, index
, 0);
1764 mutex_unlock(&tty_mutex
);
1765 tty_driver_kref_put(driver
);
1767 return PTR_ERR(tty
);
1769 filp
->private_data
= tty
;
1770 file_move(filp
, &tty
->tty_files
);
1771 check_tty_count(tty
, "tty_open");
1772 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1773 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
1775 #ifdef TTY_DEBUG_HANGUP
1776 printk(KERN_DEBUG
"opening %s...", tty
->name
);
1780 retval
= tty
->ops
->open(tty
, filp
);
1784 filp
->f_flags
= saved_flags
;
1786 if (!retval
&& test_bit(TTY_EXCLUSIVE
, &tty
->flags
) &&
1787 !capable(CAP_SYS_ADMIN
))
1791 #ifdef TTY_DEBUG_HANGUP
1792 printk(KERN_DEBUG
"error %d in opening %s...", retval
,
1795 tty_release_dev(filp
);
1796 if (retval
!= -ERESTARTSYS
)
1798 if (signal_pending(current
))
1802 * Need to reset f_op in case a hangup happened.
1804 if (filp
->f_op
== &hung_up_tty_fops
)
1805 filp
->f_op
= &tty_fops
;
1809 mutex_lock(&tty_mutex
);
1810 spin_lock_irq(¤t
->sighand
->siglock
);
1812 current
->signal
->leader
&&
1813 !current
->signal
->tty
&&
1814 tty
->session
== NULL
)
1815 __proc_set_tty(current
, tty
);
1816 spin_unlock_irq(¤t
->sighand
->siglock
);
1817 mutex_unlock(&tty_mutex
);
1821 /* BKL pushdown: scary code avoidance wrapper */
1822 static int tty_open(struct inode
*inode
, struct file
*filp
)
1827 ret
= __tty_open(inode
, filp
);
1836 * tty_release - vfs callback for close
1837 * @inode: inode of tty
1838 * @filp: file pointer for handle to tty
1840 * Called the last time each file handle is closed that references
1841 * this tty. There may however be several such references.
1844 * Takes bkl. See tty_release_dev
1847 static int tty_release(struct inode
*inode
, struct file
*filp
)
1850 tty_release_dev(filp
);
1856 * tty_poll - check tty status
1857 * @filp: file being polled
1858 * @wait: poll wait structures to update
1860 * Call the line discipline polling method to obtain the poll
1861 * status of the device.
1863 * Locking: locks called line discipline but ldisc poll method
1864 * may be re-entered freely by other callers.
1867 static unsigned int tty_poll(struct file
*filp
, poll_table
*wait
)
1869 struct tty_struct
*tty
;
1870 struct tty_ldisc
*ld
;
1873 tty
= (struct tty_struct
*)filp
->private_data
;
1874 if (tty_paranoia_check(tty
, filp
->f_path
.dentry
->d_inode
, "tty_poll"))
1877 ld
= tty_ldisc_ref_wait(tty
);
1879 ret
= (ld
->ops
->poll
)(tty
, filp
, wait
);
1880 tty_ldisc_deref(ld
);
1884 static int tty_fasync(int fd
, struct file
*filp
, int on
)
1886 struct tty_struct
*tty
;
1887 unsigned long flags
;
1891 tty
= (struct tty_struct
*)filp
->private_data
;
1892 if (tty_paranoia_check(tty
, filp
->f_path
.dentry
->d_inode
, "tty_fasync"))
1895 retval
= fasync_helper(fd
, filp
, on
, &tty
->fasync
);
1902 if (!waitqueue_active(&tty
->read_wait
))
1903 tty
->minimum_to_wake
= 1;
1904 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
1907 type
= PIDTYPE_PGID
;
1909 pid
= task_pid(current
);
1912 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
1913 retval
= __f_setown(filp
, pid
, type
, 0);
1917 if (!tty
->fasync
&& !waitqueue_active(&tty
->read_wait
))
1918 tty
->minimum_to_wake
= N_TTY_BUF_SIZE
;
1927 * tiocsti - fake input character
1928 * @tty: tty to fake input into
1929 * @p: pointer to character
1931 * Fake input to a tty device. Does the necessary locking and
1934 * FIXME: does not honour flow control ??
1937 * Called functions take tty_ldisc_lock
1938 * current->signal->tty check is safe without locks
1940 * FIXME: may race normal receive processing
1943 static int tiocsti(struct tty_struct
*tty
, char __user
*p
)
1946 struct tty_ldisc
*ld
;
1948 if ((current
->signal
->tty
!= tty
) && !capable(CAP_SYS_ADMIN
))
1950 if (get_user(ch
, p
))
1952 tty_audit_tiocsti(tty
, ch
);
1953 ld
= tty_ldisc_ref_wait(tty
);
1954 ld
->ops
->receive_buf(tty
, &ch
, &mbz
, 1);
1955 tty_ldisc_deref(ld
);
1960 * tiocgwinsz - implement window query ioctl
1962 * @arg: user buffer for result
1964 * Copies the kernel idea of the window size into the user buffer.
1966 * Locking: tty->termios_mutex is taken to ensure the winsize data
1970 static int tiocgwinsz(struct tty_struct
*tty
, struct winsize __user
*arg
)
1974 mutex_lock(&tty
->termios_mutex
);
1975 err
= copy_to_user(arg
, &tty
->winsize
, sizeof(*arg
));
1976 mutex_unlock(&tty
->termios_mutex
);
1978 return err
? -EFAULT
: 0;
1982 * tty_do_resize - resize event
1983 * @tty: tty being resized
1984 * @rows: rows (character)
1985 * @cols: cols (character)
1987 * Update the termios variables and send the neccessary signals to
1988 * peform a terminal resize correctly
1991 int tty_do_resize(struct tty_struct
*tty
, struct winsize
*ws
)
1994 unsigned long flags
;
1997 mutex_lock(&tty
->termios_mutex
);
1998 if (!memcmp(ws
, &tty
->winsize
, sizeof(*ws
)))
2000 /* Get the PID values and reference them so we can
2001 avoid holding the tty ctrl lock while sending signals */
2002 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2003 pgrp
= get_pid(tty
->pgrp
);
2004 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2007 kill_pgrp(pgrp
, SIGWINCH
, 1);
2012 mutex_unlock(&tty
->termios_mutex
);
2017 * tiocswinsz - implement window size set ioctl
2018 * @tty; tty side of tty
2019 * @arg: user buffer for result
2021 * Copies the user idea of the window size to the kernel. Traditionally
2022 * this is just advisory information but for the Linux console it
2023 * actually has driver level meaning and triggers a VC resize.
2026 * Driver dependant. The default do_resize method takes the
2027 * tty termios mutex and ctrl_lock. The console takes its own lock
2028 * then calls into the default method.
2031 static int tiocswinsz(struct tty_struct
*tty
, struct winsize __user
*arg
)
2033 struct winsize tmp_ws
;
2034 if (copy_from_user(&tmp_ws
, arg
, sizeof(*arg
)))
2037 if (tty
->ops
->resize
)
2038 return tty
->ops
->resize(tty
, &tmp_ws
);
2040 return tty_do_resize(tty
, &tmp_ws
);
2044 * tioccons - allow admin to move logical console
2045 * @file: the file to become console
2047 * Allow the adminstrator to move the redirected console device
2049 * Locking: uses redirect_lock to guard the redirect information
2052 static int tioccons(struct file
*file
)
2054 if (!capable(CAP_SYS_ADMIN
))
2056 if (file
->f_op
->write
== redirected_tty_write
) {
2058 spin_lock(&redirect_lock
);
2061 spin_unlock(&redirect_lock
);
2066 spin_lock(&redirect_lock
);
2068 spin_unlock(&redirect_lock
);
2073 spin_unlock(&redirect_lock
);
2078 * fionbio - non blocking ioctl
2079 * @file: file to set blocking value
2080 * @p: user parameter
2082 * Historical tty interfaces had a blocking control ioctl before
2083 * the generic functionality existed. This piece of history is preserved
2084 * in the expected tty API of posix OS's.
2086 * Locking: none, the open fle handle ensures it won't go away.
2089 static int fionbio(struct file
*file
, int __user
*p
)
2093 if (get_user(nonblock
, p
))
2096 spin_lock(&file
->f_lock
);
2098 file
->f_flags
|= O_NONBLOCK
;
2100 file
->f_flags
&= ~O_NONBLOCK
;
2101 spin_unlock(&file
->f_lock
);
2106 * tiocsctty - set controlling tty
2107 * @tty: tty structure
2108 * @arg: user argument
2110 * This ioctl is used to manage job control. It permits a session
2111 * leader to set this tty as the controlling tty for the session.
2114 * Takes tty_mutex() to protect tty instance
2115 * Takes tasklist_lock internally to walk sessions
2116 * Takes ->siglock() when updating signal->tty
2119 static int tiocsctty(struct tty_struct
*tty
, int arg
)
2122 if (current
->signal
->leader
&& (task_session(current
) == tty
->session
))
2125 mutex_lock(&tty_mutex
);
2127 * The process must be a session leader and
2128 * not have a controlling tty already.
2130 if (!current
->signal
->leader
|| current
->signal
->tty
) {
2137 * This tty is already the controlling
2138 * tty for another session group!
2140 if (arg
== 1 && capable(CAP_SYS_ADMIN
)) {
2144 read_lock(&tasklist_lock
);
2145 session_clear_tty(tty
->session
);
2146 read_unlock(&tasklist_lock
);
2152 proc_set_tty(current
, tty
);
2154 mutex_unlock(&tty_mutex
);
2159 * tty_get_pgrp - return a ref counted pgrp pid
2162 * Returns a refcounted instance of the pid struct for the process
2163 * group controlling the tty.
2166 struct pid
*tty_get_pgrp(struct tty_struct
*tty
)
2168 unsigned long flags
;
2171 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2172 pgrp
= get_pid(tty
->pgrp
);
2173 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2177 EXPORT_SYMBOL_GPL(tty_get_pgrp
);
2180 * tiocgpgrp - get process group
2181 * @tty: tty passed by user
2182 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2185 * Obtain the process group of the tty. If there is no process group
2188 * Locking: none. Reference to current->signal->tty is safe.
2191 static int tiocgpgrp(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
2196 * (tty == real_tty) is a cheap way of
2197 * testing if the tty is NOT a master pty.
2199 if (tty
== real_tty
&& current
->signal
->tty
!= real_tty
)
2201 pid
= tty_get_pgrp(real_tty
);
2202 ret
= put_user(pid_vnr(pid
), p
);
2208 * tiocspgrp - attempt to set process group
2209 * @tty: tty passed by user
2210 * @real_tty: tty side device matching tty passed by user
2213 * Set the process group of the tty to the session passed. Only
2214 * permitted where the tty session is our session.
2216 * Locking: RCU, ctrl lock
2219 static int tiocspgrp(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
2223 int retval
= tty_check_change(real_tty
);
2224 unsigned long flags
;
2230 if (!current
->signal
->tty
||
2231 (current
->signal
->tty
!= real_tty
) ||
2232 (real_tty
->session
!= task_session(current
)))
2234 if (get_user(pgrp_nr
, p
))
2239 pgrp
= find_vpid(pgrp_nr
);
2244 if (session_of_pgrp(pgrp
) != task_session(current
))
2247 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2248 put_pid(real_tty
->pgrp
);
2249 real_tty
->pgrp
= get_pid(pgrp
);
2250 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2257 * tiocgsid - get session id
2258 * @tty: tty passed by user
2259 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2260 * @p: pointer to returned session id
2262 * Obtain the session id of the tty. If there is no session
2265 * Locking: none. Reference to current->signal->tty is safe.
2268 static int tiocgsid(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
2271 * (tty == real_tty) is a cheap way of
2272 * testing if the tty is NOT a master pty.
2274 if (tty
== real_tty
&& current
->signal
->tty
!= real_tty
)
2276 if (!real_tty
->session
)
2278 return put_user(pid_vnr(real_tty
->session
), p
);
2282 * tiocsetd - set line discipline
2284 * @p: pointer to user data
2286 * Set the line discipline according to user request.
2288 * Locking: see tty_set_ldisc, this function is just a helper
2291 static int tiocsetd(struct tty_struct
*tty
, int __user
*p
)
2296 if (get_user(ldisc
, p
))
2300 ret
= tty_set_ldisc(tty
, ldisc
);
2307 * send_break - performed time break
2308 * @tty: device to break on
2309 * @duration: timeout in mS
2311 * Perform a timed break on hardware that lacks its own driver level
2312 * timed break functionality.
2315 * atomic_write_lock serializes
2319 static int send_break(struct tty_struct
*tty
, unsigned int duration
)
2323 if (tty
->ops
->break_ctl
== NULL
)
2326 if (tty
->driver
->flags
& TTY_DRIVER_HARDWARE_BREAK
)
2327 retval
= tty
->ops
->break_ctl(tty
, duration
);
2329 /* Do the work ourselves */
2330 if (tty_write_lock(tty
, 0) < 0)
2332 retval
= tty
->ops
->break_ctl(tty
, -1);
2335 if (!signal_pending(current
))
2336 msleep_interruptible(duration
);
2337 retval
= tty
->ops
->break_ctl(tty
, 0);
2339 tty_write_unlock(tty
);
2340 if (signal_pending(current
))
2347 * tty_tiocmget - get modem status
2349 * @file: user file pointer
2350 * @p: pointer to result
2352 * Obtain the modem status bits from the tty driver if the feature
2353 * is supported. Return -EINVAL if it is not available.
2355 * Locking: none (up to the driver)
2358 static int tty_tiocmget(struct tty_struct
*tty
, struct file
*file
, int __user
*p
)
2360 int retval
= -EINVAL
;
2362 if (tty
->ops
->tiocmget
) {
2363 retval
= tty
->ops
->tiocmget(tty
, file
);
2366 retval
= put_user(retval
, p
);
2372 * tty_tiocmset - set modem status
2374 * @file: user file pointer
2375 * @cmd: command - clear bits, set bits or set all
2376 * @p: pointer to desired bits
2378 * Set the modem status bits from the tty driver if the feature
2379 * is supported. Return -EINVAL if it is not available.
2381 * Locking: none (up to the driver)
2384 static int tty_tiocmset(struct tty_struct
*tty
, struct file
*file
, unsigned int cmd
,
2388 unsigned int set
, clear
, val
;
2390 if (tty
->ops
->tiocmset
== NULL
)
2393 retval
= get_user(val
, p
);
2409 set
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
2410 clear
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
2411 return tty
->ops
->tiocmset(tty
, file
, set
, clear
);
2414 struct tty_struct
*tty_pair_get_tty(struct tty_struct
*tty
)
2416 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2417 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
2421 EXPORT_SYMBOL(tty_pair_get_tty
);
2423 struct tty_struct
*tty_pair_get_pty(struct tty_struct
*tty
)
2425 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2426 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
2430 EXPORT_SYMBOL(tty_pair_get_pty
);
2433 * Split this up, as gcc can choke on it otherwise..
2435 long tty_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
2437 struct tty_struct
*tty
, *real_tty
;
2438 void __user
*p
= (void __user
*)arg
;
2440 struct tty_ldisc
*ld
;
2441 struct inode
*inode
= file
->f_dentry
->d_inode
;
2443 tty
= (struct tty_struct
*)file
->private_data
;
2444 if (tty_paranoia_check(tty
, inode
, "tty_ioctl"))
2447 real_tty
= tty_pair_get_tty(tty
);
2450 * Factor out some common prep work
2458 retval
= tty_check_change(tty
);
2461 if (cmd
!= TIOCCBRK
) {
2462 tty_wait_until_sent(tty
, 0);
2463 if (signal_pending(current
))
2474 return tiocsti(tty
, p
);
2476 return tiocgwinsz(real_tty
, p
);
2478 return tiocswinsz(real_tty
, p
);
2480 return real_tty
!= tty
? -EINVAL
: tioccons(file
);
2482 return fionbio(file
, p
);
2484 set_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2487 clear_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2490 if (current
->signal
->tty
!= tty
)
2495 return tiocsctty(tty
, arg
);
2497 return tiocgpgrp(tty
, real_tty
, p
);
2499 return tiocspgrp(tty
, real_tty
, p
);
2501 return tiocgsid(tty
, real_tty
, p
);
2503 return put_user(tty
->ldisc
->ops
->num
, (int __user
*)p
);
2505 return tiocsetd(tty
, p
);
2509 case TIOCSBRK
: /* Turn break on, unconditionally */
2510 if (tty
->ops
->break_ctl
)
2511 return tty
->ops
->break_ctl(tty
, -1);
2513 case TIOCCBRK
: /* Turn break off, unconditionally */
2514 if (tty
->ops
->break_ctl
)
2515 return tty
->ops
->break_ctl(tty
, 0);
2517 case TCSBRK
: /* SVID version: non-zero arg --> no break */
2518 /* non-zero arg means wait for all output data
2519 * to be sent (performed above) but don't send break.
2520 * This is used by the tcdrain() termios function.
2523 return send_break(tty
, 250);
2525 case TCSBRKP
: /* support for POSIX tcsendbreak() */
2526 return send_break(tty
, arg
? arg
*100 : 250);
2529 return tty_tiocmget(tty
, file
, p
);
2533 return tty_tiocmset(tty
, file
, cmd
, p
);
2538 /* flush tty buffer and allow ldisc to process ioctl */
2539 tty_buffer_flush(tty
);
2544 if (tty
->ops
->ioctl
) {
2545 retval
= (tty
->ops
->ioctl
)(tty
, file
, cmd
, arg
);
2546 if (retval
!= -ENOIOCTLCMD
)
2549 ld
= tty_ldisc_ref_wait(tty
);
2551 if (ld
->ops
->ioctl
) {
2552 retval
= ld
->ops
->ioctl(tty
, file
, cmd
, arg
);
2553 if (retval
== -ENOIOCTLCMD
)
2556 tty_ldisc_deref(ld
);
2560 #ifdef CONFIG_COMPAT
2561 static long tty_compat_ioctl(struct file
*file
, unsigned int cmd
,
2564 struct inode
*inode
= file
->f_dentry
->d_inode
;
2565 struct tty_struct
*tty
= file
->private_data
;
2566 struct tty_ldisc
*ld
;
2567 int retval
= -ENOIOCTLCMD
;
2569 if (tty_paranoia_check(tty
, inode
, "tty_ioctl"))
2572 if (tty
->ops
->compat_ioctl
) {
2573 retval
= (tty
->ops
->compat_ioctl
)(tty
, file
, cmd
, arg
);
2574 if (retval
!= -ENOIOCTLCMD
)
2578 ld
= tty_ldisc_ref_wait(tty
);
2579 if (ld
->ops
->compat_ioctl
)
2580 retval
= ld
->ops
->compat_ioctl(tty
, file
, cmd
, arg
);
2581 tty_ldisc_deref(ld
);
2588 * This implements the "Secure Attention Key" --- the idea is to
2589 * prevent trojan horses by killing all processes associated with this
2590 * tty when the user hits the "Secure Attention Key". Required for
2591 * super-paranoid applications --- see the Orange Book for more details.
2593 * This code could be nicer; ideally it should send a HUP, wait a few
2594 * seconds, then send a INT, and then a KILL signal. But you then
2595 * have to coordinate with the init process, since all processes associated
2596 * with the current tty must be dead before the new getty is allowed
2599 * Now, if it would be correct ;-/ The current code has a nasty hole -
2600 * it doesn't catch files in flight. We may send the descriptor to ourselves
2601 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2603 * Nasty bug: do_SAK is being called in interrupt context. This can
2604 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2606 void __do_SAK(struct tty_struct
*tty
)
2611 struct task_struct
*g
, *p
;
2612 struct pid
*session
;
2615 struct fdtable
*fdt
;
2619 session
= tty
->session
;
2621 tty_ldisc_flush(tty
);
2623 tty_driver_flush_buffer(tty
);
2625 read_lock(&tasklist_lock
);
2626 /* Kill the entire session */
2627 do_each_pid_task(session
, PIDTYPE_SID
, p
) {
2628 printk(KERN_NOTICE
"SAK: killed process %d"
2629 " (%s): task_session(p)==tty->session\n",
2630 task_pid_nr(p
), p
->comm
);
2631 send_sig(SIGKILL
, p
, 1);
2632 } while_each_pid_task(session
, PIDTYPE_SID
, p
);
2633 /* Now kill any processes that happen to have the
2636 do_each_thread(g
, p
) {
2637 if (p
->signal
->tty
== tty
) {
2638 printk(KERN_NOTICE
"SAK: killed process %d"
2639 " (%s): task_session(p)==tty->session\n",
2640 task_pid_nr(p
), p
->comm
);
2641 send_sig(SIGKILL
, p
, 1);
2647 * We don't take a ref to the file, so we must
2648 * hold ->file_lock instead.
2650 spin_lock(&p
->files
->file_lock
);
2651 fdt
= files_fdtable(p
->files
);
2652 for (i
= 0; i
< fdt
->max_fds
; i
++) {
2653 filp
= fcheck_files(p
->files
, i
);
2656 if (filp
->f_op
->read
== tty_read
&&
2657 filp
->private_data
== tty
) {
2658 printk(KERN_NOTICE
"SAK: killed process %d"
2659 " (%s): fd#%d opened to the tty\n",
2660 task_pid_nr(p
), p
->comm
, i
);
2661 force_sig(SIGKILL
, p
);
2665 spin_unlock(&p
->files
->file_lock
);
2668 } while_each_thread(g
, p
);
2669 read_unlock(&tasklist_lock
);
2673 static void do_SAK_work(struct work_struct
*work
)
2675 struct tty_struct
*tty
=
2676 container_of(work
, struct tty_struct
, SAK_work
);
2681 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2682 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2683 * the values which we write to it will be identical to the values which it
2684 * already has. --akpm
2686 void do_SAK(struct tty_struct
*tty
)
2690 schedule_work(&tty
->SAK_work
);
2693 EXPORT_SYMBOL(do_SAK
);
2696 * initialize_tty_struct
2697 * @tty: tty to initialize
2699 * This subroutine initializes a tty structure that has been newly
2702 * Locking: none - tty in question must not be exposed at this point
2705 void initialize_tty_struct(struct tty_struct
*tty
,
2706 struct tty_driver
*driver
, int idx
)
2708 memset(tty
, 0, sizeof(struct tty_struct
));
2709 kref_init(&tty
->kref
);
2710 tty
->magic
= TTY_MAGIC
;
2711 tty_ldisc_init(tty
);
2712 tty
->session
= NULL
;
2714 tty
->overrun_time
= jiffies
;
2715 tty
->buf
.head
= tty
->buf
.tail
= NULL
;
2716 tty_buffer_init(tty
);
2717 mutex_init(&tty
->termios_mutex
);
2718 mutex_init(&tty
->ldisc_mutex
);
2719 init_waitqueue_head(&tty
->write_wait
);
2720 init_waitqueue_head(&tty
->read_wait
);
2721 INIT_WORK(&tty
->hangup_work
, do_tty_hangup
);
2722 mutex_init(&tty
->atomic_read_lock
);
2723 mutex_init(&tty
->atomic_write_lock
);
2724 mutex_init(&tty
->output_lock
);
2725 mutex_init(&tty
->echo_lock
);
2726 spin_lock_init(&tty
->read_lock
);
2727 spin_lock_init(&tty
->ctrl_lock
);
2728 INIT_LIST_HEAD(&tty
->tty_files
);
2729 INIT_WORK(&tty
->SAK_work
, do_SAK_work
);
2731 tty
->driver
= driver
;
2732 tty
->ops
= driver
->ops
;
2734 tty_line_name(driver
, idx
, tty
->name
);
2738 * tty_put_char - write one character to a tty
2742 * Write one byte to the tty using the provided put_char method
2743 * if present. Returns the number of characters successfully output.
2745 * Note: the specific put_char operation in the driver layer may go
2746 * away soon. Don't call it directly, use this method
2749 int tty_put_char(struct tty_struct
*tty
, unsigned char ch
)
2751 if (tty
->ops
->put_char
)
2752 return tty
->ops
->put_char(tty
, ch
);
2753 return tty
->ops
->write(tty
, &ch
, 1);
2755 EXPORT_SYMBOL_GPL(tty_put_char
);
2757 struct class *tty_class
;
2760 * tty_register_device - register a tty device
2761 * @driver: the tty driver that describes the tty device
2762 * @index: the index in the tty driver for this tty device
2763 * @device: a struct device that is associated with this tty device.
2764 * This field is optional, if there is no known struct device
2765 * for this tty device it can be set to NULL safely.
2767 * Returns a pointer to the struct device for this tty device
2768 * (or ERR_PTR(-EFOO) on error).
2770 * This call is required to be made to register an individual tty device
2771 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2772 * that bit is not set, this function should not be called by a tty
2778 struct device
*tty_register_device(struct tty_driver
*driver
, unsigned index
,
2779 struct device
*device
)
2782 dev_t dev
= MKDEV(driver
->major
, driver
->minor_start
) + index
;
2784 if (index
>= driver
->num
) {
2785 printk(KERN_ERR
"Attempt to register invalid tty line number "
2787 return ERR_PTR(-EINVAL
);
2790 if (driver
->type
== TTY_DRIVER_TYPE_PTY
)
2791 pty_line_name(driver
, index
, name
);
2793 tty_line_name(driver
, index
, name
);
2795 return device_create(tty_class
, device
, dev
, NULL
, name
);
2797 EXPORT_SYMBOL(tty_register_device
);
2800 * tty_unregister_device - unregister a tty device
2801 * @driver: the tty driver that describes the tty device
2802 * @index: the index in the tty driver for this tty device
2804 * If a tty device is registered with a call to tty_register_device() then
2805 * this function must be called when the tty device is gone.
2810 void tty_unregister_device(struct tty_driver
*driver
, unsigned index
)
2812 device_destroy(tty_class
,
2813 MKDEV(driver
->major
, driver
->minor_start
) + index
);
2815 EXPORT_SYMBOL(tty_unregister_device
);
2817 struct tty_driver
*alloc_tty_driver(int lines
)
2819 struct tty_driver
*driver
;
2821 driver
= kzalloc(sizeof(struct tty_driver
), GFP_KERNEL
);
2823 kref_init(&driver
->kref
);
2824 driver
->magic
= TTY_DRIVER_MAGIC
;
2825 driver
->num
= lines
;
2826 /* later we'll move allocation of tables here */
2830 EXPORT_SYMBOL(alloc_tty_driver
);
2832 static void destruct_tty_driver(struct kref
*kref
)
2834 struct tty_driver
*driver
= container_of(kref
, struct tty_driver
, kref
);
2836 struct ktermios
*tp
;
2839 if (driver
->flags
& TTY_DRIVER_INSTALLED
) {
2841 * Free the termios and termios_locked structures because
2842 * we don't want to get memory leaks when modular tty
2843 * drivers are removed from the kernel.
2845 for (i
= 0; i
< driver
->num
; i
++) {
2846 tp
= driver
->termios
[i
];
2848 driver
->termios
[i
] = NULL
;
2851 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
))
2852 tty_unregister_device(driver
, i
);
2855 proc_tty_unregister_driver(driver
);
2856 driver
->ttys
= NULL
;
2857 driver
->termios
= NULL
;
2859 cdev_del(&driver
->cdev
);
2864 void tty_driver_kref_put(struct tty_driver
*driver
)
2866 kref_put(&driver
->kref
, destruct_tty_driver
);
2868 EXPORT_SYMBOL(tty_driver_kref_put
);
2870 void tty_set_operations(struct tty_driver
*driver
,
2871 const struct tty_operations
*op
)
2875 EXPORT_SYMBOL(tty_set_operations
);
2877 void put_tty_driver(struct tty_driver
*d
)
2879 tty_driver_kref_put(d
);
2881 EXPORT_SYMBOL(put_tty_driver
);
2884 * Called by a tty driver to register itself.
2886 int tty_register_driver(struct tty_driver
*driver
)
2893 if (!(driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) && driver
->num
) {
2894 p
= kzalloc(driver
->num
* 2 * sizeof(void *), GFP_KERNEL
);
2899 if (!driver
->major
) {
2900 error
= alloc_chrdev_region(&dev
, driver
->minor_start
,
2901 driver
->num
, driver
->name
);
2903 driver
->major
= MAJOR(dev
);
2904 driver
->minor_start
= MINOR(dev
);
2907 dev
= MKDEV(driver
->major
, driver
->minor_start
);
2908 error
= register_chrdev_region(dev
, driver
->num
, driver
->name
);
2916 driver
->ttys
= (struct tty_struct
**)p
;
2917 driver
->termios
= (struct ktermios
**)(p
+ driver
->num
);
2919 driver
->ttys
= NULL
;
2920 driver
->termios
= NULL
;
2923 cdev_init(&driver
->cdev
, &tty_fops
);
2924 driver
->cdev
.owner
= driver
->owner
;
2925 error
= cdev_add(&driver
->cdev
, dev
, driver
->num
);
2927 unregister_chrdev_region(dev
, driver
->num
);
2928 driver
->ttys
= NULL
;
2929 driver
->termios
= NULL
;
2934 mutex_lock(&tty_mutex
);
2935 list_add(&driver
->tty_drivers
, &tty_drivers
);
2936 mutex_unlock(&tty_mutex
);
2938 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
)) {
2939 for (i
= 0; i
< driver
->num
; i
++)
2940 tty_register_device(driver
, i
, NULL
);
2942 proc_tty_register_driver(driver
);
2943 driver
->flags
|= TTY_DRIVER_INSTALLED
;
2947 EXPORT_SYMBOL(tty_register_driver
);
2950 * Called by a tty driver to unregister itself.
2952 int tty_unregister_driver(struct tty_driver
*driver
)
2956 if (driver
->refcount
)
2959 unregister_chrdev_region(MKDEV(driver
->major
, driver
->minor_start
),
2961 mutex_lock(&tty_mutex
);
2962 list_del(&driver
->tty_drivers
);
2963 mutex_unlock(&tty_mutex
);
2967 EXPORT_SYMBOL(tty_unregister_driver
);
2969 dev_t
tty_devnum(struct tty_struct
*tty
)
2971 return MKDEV(tty
->driver
->major
, tty
->driver
->minor_start
) + tty
->index
;
2973 EXPORT_SYMBOL(tty_devnum
);
2975 void proc_clear_tty(struct task_struct
*p
)
2977 unsigned long flags
;
2978 struct tty_struct
*tty
;
2979 spin_lock_irqsave(&p
->sighand
->siglock
, flags
);
2980 tty
= p
->signal
->tty
;
2981 p
->signal
->tty
= NULL
;
2982 spin_unlock_irqrestore(&p
->sighand
->siglock
, flags
);
2986 /* Called under the sighand lock */
2988 static void __proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
)
2991 unsigned long flags
;
2992 /* We should not have a session or pgrp to put here but.... */
2993 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2994 put_pid(tty
->session
);
2996 tty
->pgrp
= get_pid(task_pgrp(tsk
));
2997 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2998 tty
->session
= get_pid(task_session(tsk
));
2999 if (tsk
->signal
->tty
) {
3000 printk(KERN_DEBUG
"tty not NULL!!\n");
3001 tty_kref_put(tsk
->signal
->tty
);
3004 put_pid(tsk
->signal
->tty_old_pgrp
);
3005 tsk
->signal
->tty
= tty_kref_get(tty
);
3006 tsk
->signal
->tty_old_pgrp
= NULL
;
3009 static void proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
)
3011 spin_lock_irq(&tsk
->sighand
->siglock
);
3012 __proc_set_tty(tsk
, tty
);
3013 spin_unlock_irq(&tsk
->sighand
->siglock
);
3016 struct tty_struct
*get_current_tty(void)
3018 struct tty_struct
*tty
;
3019 unsigned long flags
;
3021 spin_lock_irqsave(¤t
->sighand
->siglock
, flags
);
3022 tty
= tty_kref_get(current
->signal
->tty
);
3023 spin_unlock_irqrestore(¤t
->sighand
->siglock
, flags
);
3026 EXPORT_SYMBOL_GPL(get_current_tty
);
3028 void tty_default_fops(struct file_operations
*fops
)
3034 * Initialize the console device. This is called *early*, so
3035 * we can't necessarily depend on lots of kernel help here.
3036 * Just do some early initializations, and do the complex setup
3039 void __init
console_init(void)
3043 /* Setup the default TTY line discipline. */
3047 * set up the console device so that later boot sequences can
3048 * inform about problems etc..
3050 call
= __con_initcall_start
;
3051 while (call
< __con_initcall_end
) {
3057 static int __init
tty_class_init(void)
3059 tty_class
= class_create(THIS_MODULE
, "tty");
3060 if (IS_ERR(tty_class
))
3061 return PTR_ERR(tty_class
);
3065 postcore_initcall(tty_class_init
);
3067 /* 3/2004 jmc: why do these devices exist? */
3069 static struct cdev tty_cdev
, console_cdev
;
3072 * Ok, now we can initialize the rest of the tty devices and can count
3073 * on memory allocations, interrupts etc..
3075 static int __init
tty_init(void)
3077 cdev_init(&tty_cdev
, &tty_fops
);
3078 if (cdev_add(&tty_cdev
, MKDEV(TTYAUX_MAJOR
, 0), 1) ||
3079 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 0), 1, "/dev/tty") < 0)
3080 panic("Couldn't register /dev/tty driver\n");
3081 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 0), NULL
,
3084 cdev_init(&console_cdev
, &console_fops
);
3085 if (cdev_add(&console_cdev
, MKDEV(TTYAUX_MAJOR
, 1), 1) ||
3086 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 1), 1, "/dev/console") < 0)
3087 panic("Couldn't register /dev/console driver\n");
3088 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 1), NULL
,
3092 vty_init(&console_fops
);
3096 module_init(tty_init
);